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Thread
2006-01-22 by roel_cnc
i like the idea of making me own laserplotter. tested: a pointerlaser (some cheap thing) with an extra focus lense, a red sensible film gave me super fine lines (close to a single cloth fiber). did any of us fouling around with this idea !! tips and suggestions always welcome:) gr Roel (holland)
2006-01-22 by Adam Seychell
roel_cnc wrote: > i like the idea of making me own laserplotter. > > tested: a pointerlaser (some cheap thing) with an extra focus lense, a > red sensible film gave me super fine lines (close to a single cloth > fiber). > > did any of us fouling around with this idea !! > > tips and suggestions always welcome:) > > gr Roel (holland) > > Are you talking a rotating drum laser photoplotter ? Any idea of suitable low cost (<$5 A3 sheet) red light photosensitive film ? There is also the problem of developing red light sensitive films! Alternative is green, blue or even UV laser diodes. Choice depends on photofilm and laser diode availability. Maybe the best approach is to look at traditional black&white photographic films, and then decide on suitable laser diode wavelength. Use common B&W films that are processed with a standard red safe lights. At say 20um wide pixel, that gives 15000 drum revolutions to scan a length of 300mm. If drum spins at 1000 RPM, thats 15 minutes to complete, which is acceptable. Regarding film mounting, it is ideal to have the film placed on the inside of a drum cylinder. The drawback with this approach is building single sided bearing mount system for the drum. I guess thats all up to degree of mechanical balancing. Would be interesting hearing ideas too. Adam
2006-01-23 by roel_cnc
--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell <a_seychell@y...> wrote: > > roel_cnc wrote: > > i like the idea of making me own laserplotter. > > > > tested: a pointerlaser (some cheap thing) with an extra focus lense, a > > red sensible film gave me super fine lines (close to a single cloth > > fiber). > > > > did any of us fouling around with this idea !! > > > > tips and suggestions always welcome:) > > > > gr Roel (holland) > > > > > > Are you talking a rotating drum laser photoplotter ? > > Any idea of suitable low cost (<$5 A3 sheet) red light photosensitive film ? > > There is also the problem of developing red light sensitive films! > > Alternative is green, blue or even UV laser diodes. Choice depends on > photofilm and laser diode availability. Maybe the best approach is to > look at traditional black&white photographic films, and then decide on > suitable laser diode wavelength. Use common B&W films that are processed > with a standard red safe lights. > > At say 20um wide pixel, that gives 15000 drum revolutions to scan a > length of 300mm. If drum spins at 1000 RPM, thats 15 minutes to > complete, which is acceptable. > Regarding film mounting, it is ideal to have the film placed on the > inside of a drum cylinder. The drawback with this approach is building > single sided bearing mount system for the drum. I guess thats all up to > degree of mechanical balancing. > > Would be interesting hearing ideas too. > > Adam > hi Adam, Drum type would be nice but controlling and software tooks a great deal of time to create i think ! must be somthing like a tv set creating a image on the screen with sync goto next line :) lol gr. Roel
2006-01-23 by Adam Seychell
roel_cnc wrote: > > hi Adam, > > Drum type would be nice but controlling and software tooks a great > deal of time to create i think ! > must be somthing like a tv set creating a image on the screen with > sync goto next line :) lol > > > gr. Roel I'd be interested what you have discovered about photofilms for a home made plotter. Let us know anything that converts your cheap laser into raster scanning 20um beam projection. I think more brain power would be required to devise software to compensate fringing of the projected beam as would to the accurate and well predicted spiral mapping in a drum plotter. If one were to build a < 50um resolution photoplotter then the only feasible method is with a rotating drum. I'd be interested any anyone's thoughts.
2006-01-23 by Leon Heller
----- Original Message -----
From: "Adam Seychell" <a_seychell@...> To: <Homebrew_PCBs@yahoogroups.com> Sent: Monday, January 23, 2006 2:40 AM Subject: Re: [Homebrew_PCBs] Re: homebrew laser plotter > roel_cnc wrote: > >> >> hi Adam, >> >> Drum type would be nice but controlling and software tooks a great >> deal of time to create i think ! >> must be somthing like a tv set creating a image on the screen with >> sync goto next line :) lol >> >> >> gr. Roel > > > I'd be interested what you have discovered about photofilms for a home > made plotter. Let us know anything that converts your cheap laser into > raster scanning 20um beam projection. I think more brain power would be > required to devise software to compensate fringing of the projected beam > as would to the accurate and well predicted spiral mapping in a drum > plotter. If one were to build a < 50um resolution photoplotter then the > only feasible method is with a rotating drum. I'd be interested any > anyone's thoughts. Mega Electronics sells film for use with their laser plotter (it uses a drum). Leon -- Leon Heller, G1HSM leon.heller@... http://www.geocities.com/leon_heller
2006-01-23 by Yngve Dahlstrom
Leon Heller <leon.heller@...> wrote: ----- Original Message -----
From: "Adam Seychell" <a_seychell@...> To: <Homebrew_PCBs@yahoogroups.com> Sent: Monday, January 23, 2006 2:40 AM Subject: Re: [Homebrew_PCBs] Re: homebrew laser plotter > roel_cnc wrote: > >> >> hi Adam, >> >> Drum type would be nice but controlling and software tooks a great >> deal of time to create i think ! >> must be somthing like a tv set creating a image on the screen with >> sync goto next line :) lol >> >> >> gr. Roel > > > I'd be interested what you have discovered about photofilms for a home > made plotter. Let us know anything that converts your cheap laser into > raster scanning 20um beam projection. I think more brain power would be > required to devise software to compensate fringing of the projected beam > as would to the accurate and well predicted spiral mapping in a drum > plotter. If one were to build a < 50um resolution photoplotter then the > only feasible method is with a rotating drum. I'd be interested any > anyone's thoughts. Mega Electronics sells film for use with their laser plotter (it uses a drum). Might be possible to hack an old HP LJ engine if you substitute the IR laser with something the film is sensitive to. Still sounds like a project more for self-education/entertainment than of practical value. - YD. --------------------------------- Yahoo! Autos. Looking for a sweet ride? Get pricing, reviews, & more on new and used cars. [Non-text portions of this message have been removed]
2006-04-28 by cunningfellow
>> roel_cnc wrote: >> i like the idea of making me own laserplotter. <SNIP> I like the idea too - so am going to try recreate something half way between the pico-systems one and the one bungard are selling. > Adam Seychell wrote > Are you talking a rotating drum laser photoplotter ? Only sensible way to do it. > Any idea of suitable low cost (<$5 A3 sheet) red > light photosensitive film ? Have just found out I can get some red sensitve film for about <$3 AUD an A4 sheet. (<$6AUD for A3 if that is close enough to the mark for you Adam) <SNIP stuff about other colours> > At say 20um wide pixel, that gives 15000 drum > revolutions to scan a length of 300mm. If drum > spins at 1000 RPM, thats 15 minutes to complete, > which is acceptable. I can't remember the last time I did a board 300mm wide. So at 1000 RPM I reckon I would only be waiting 5 minutes. Still - I would be happy at 1 hour to get a decent density to my blacks. In fact having it take an hour would be an avantage to me - it would make me check for mistakes more thouroughly :D <SNIP stuff about mechanics> > Would be interesting hearing ideas too. I have started having a go at it. Have put together a board with a 74HCT4046 Phase Lock Loop and some other stuff to multiply the encoder wheel from a servo motor. (and an ATMEL - apparently its against the law these days to build something without either a PIC or an Atmel on it) Worked out my 7x10 minilathe isn't big enough to turn up the drum. Going to have to steal a mates lathe for that. Have speced/thought out an interface to dump a BMP file from a PC out to a laser (synced to the PLL above) Two parts I have not thought through yet are the laser diode driver circuit and the carraige for the laser. Laser diode driver might end end up being an off the peg solution so should not be too hard. The carraige however I am undecided on. A belt, a coach screw or a ball nut. The $1000 for a ballnut/ screw does not scare me too much. However if any of the other homebrew guys out there want to make one it might be a silly choice. Whats everyone elses idea ? Also do people want to see what I have done so far ?
2006-04-28 by Lez
Yes, pics please! I am intersted in how your going to get the bmp out to a laser diode etc. Reminds me of a paintjet (a real one, with paint, and an airbrush using a jet of air) that was built in about 1990 on an amiga, did very very large prints 2 metres etc and drum was turned by something odd like a bicycle chain and a drill.....
2006-04-28 by cunningfellow
> Lez wrote: > Yes, pics please! Your wish is my command. Check the files section. "Laser Plotter" I didn't take a photo of the bottom side to avoid the merciless piss taking and cold solder joint counting that seems to accompany solder photos in here :D > I am intersted in how your going to get the bmp out > to a laser diode etc. Will start a new thread for details on what I have done so far. To be honest, I didn't realy want to build anything at all. I just felt someone had to build/do something to affect the signal to noise ratio in the "My mothers inkjet ink can resist etching better than your mothers inkjet ink" saga. It would almost be worth starting a "Macs suck - Amiga Forever" flame war to have a post that didn't mention toner transfer or MIS inks :D andrewm
2006-04-28 by Lez
Like the blue circuit board pic, whats it done with?
2006-04-28 by cunningfellow
--- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@...> wrote: > > Like the blue circuit board pic, whats it done with? > Alt-PrintScreen and a bit of elbow grease.
2006-04-28 by Lez
Thats where I'm going wrong, I'm using time and diptrace. On 28/04/06, cunningfellow <andrewm1973@...> wrote: > --- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@...> wrote: > > > > Like the blue circuit board pic, whats it done with? > > > > Alt-PrintScreen and a bit of elbow grease. > > > > > > > Be sure to visit the group home and check for new Links, Files, and Photos: > http://groups.yahoo.com/group/Homebrew_PCBs > > If Files or Photos are running short of space, post them here: > http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ > Yahoo! Groups Links > > > > > > > -- Lez - Looking for early starwars (episode 4, original starwars) recordings, even pirate - - I dont need your originals just some information about running time - and scene cut points - - - also looking for a car, silver or white, 4 doors - - diesel with a bosch pump, abs and pas - - aircon would be nice, and not a ford -
2006-04-28 by cunningfellow
> > > Lez Wrote: > > > Like the blue circuit board pic, whats it done with? > > > > > Andrew wrote: > > Alt-PrintScreen and a bit of elbow grease. > > > Lez wrote: > Thats where I'm going wrong, I'm using time and diptrace. The actual software I use is Easytrax an old freeware version of protel for DOS. To get the blue PNG of the PCB I go to windows, load the PCB file into a cripple-ware demo version of protel for windows. Then I zoom in to about 4x screen size. Cut-n- paste into paint 4 times. Stitch them together. The cripple-ness on the protel for windows demo is that the save function is disabled. I'm glad they did that rather than having a 30 day timed trial. I don't want to save from it - I much prefer to do my layup in the DOS version. I have tried the newer version of Protel and have not liked the loss of simplicity from the DOS version. PLUS living in Australia if I used any CAD software from another company, I would have the anti-protel police come around to my house, beat me up and rape my dog. andrewm
2006-04-28 by roger lucas
>--- cunningfellow <andrewm1973@...> wrote:
>
>Have speced/thought out an interface to dump a BMP
>file from a PC out to a laser (synced to the PLL
>above)
>
>Whats everyone elses idea ?
>
>Also do people want to see what I have done so far ?
I am just starting to try to figure out BMP to raster
for the PCB EDM MILL for which I have just finished
the drive electronics,and xyz's. Because there are no
significant forces involved I have been able to use
the lightest of mechanisms.
Would be interested in your approach, the only
significant difference between our machines is that I
am essentially driving the spark generator whereas you
are driving the laser. Are you dumping the BMP file to
a separate micro or driving an interface direcly from
the PC? PC's are not my strong point, but PIC's and
Atmel are ok.
Yes, I would like to see what you have done so far,
PLEASE.
To all who are interested in the progress of the PCB
EDM MILL, I have produced a very simple clone of the
Garden of Edm circuit, modified with some hints from
Curt Richards (Curt are you still out there?).
Just got to figure out BMP to Raster scan
interpolation. If anybody else has any ideas please
say.
Roger
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Introducing the new Yahoo! Answers Beta \ufffd A new place to get answers to your questions \ufffd Try it http://uk.answers.yahoo.com2006-04-28 by cunningfellow
> >andrewm1973@ wrote: > >Have speced/thought out an interface to dump a BMP > >file from a PC out to a laser > Roger Lucas wrote: > I am just starting to try to figure out BMP to raster > for the PCB EDM MILL for which I have just finished > the drive electronics <SNIP> > Would be interested in your approach <SNIP> > Are you dumping the BMP file to > a separate micro or driving an interface direcly from > the PC? <SNIP> > To all who are interested in the progress of the PCB > EDM MILL, I have produced a very simple clone of the > Garden of Edm circuit, modified with some hints from > Curt Richards (Curt are you still out there?). > Just got to figure out BMP to Raster scan > interpolation. If anybody else has any ideas please > say. Roger - Will you marry me :D I so want to build an EDM for my machine shop. I can't bring myself to build a spark-oscillator one for moral reasons (it doesn't have an Atmel in it). Also the garden_of_EDM looked too "thesis" project for me (here is the idea, I am sure it would have worked if we had more time to finish it) It is another one of those "I will do it when I have spare time" projects. If someone else is going to iron out the bugs in Garden_of_EDM and give me an RTFM idiots guide I will be so happy. I will also be able to start my experiments to see if using stray cats as a new form of dilectric has any merit :D BUT to answer your questions. I am dumping the BMP file to a seperate Micro. There is going to be an ATMega in the laser plotter to run the whole show. I am going to try make it as universal as possible, not stuck on Wintel machines. This is so people with other computers like *nix, Amigas, RiscOS and VZ200s can use it. Even people that dont have computers and only use macs could try it. (wonder if that flame bait will work) The idea is to have the ATMEL sit on a seriel port, then you run some terminal software on the PC and xmodem transfer the file to it. The Atmel then turns the BMP file into a series of dots. I guess it would be easy enough for you to adapt it to burn holes with a spark rather than pulse out a laser. I was going to use TIFF file format with G3 fax compression instead of BMP. On most PCB files you will get about a 10:1 compression ratio with G3. This might be important if I do manage to get 2000 dpi out of the laser. The 1 megabaud limit of the FT232 chip I will use and a BMP would be a bottle neck. I know I could use an AT90USB128 but that would defeat the purpose of being free from writing any PC software :D The ATMega at 16Mhz should have pleanty 'nuff balls to XModem, CRC, drive stepper, driver servo, drive laser and decode G3-Fax without working up a sweat. Worst case senario and I can't get an atmel to decode G3 fax - I will hang my head in shame, do my own RLE compression in software on the PC side and admit to the world in general that pop-up-toasters do in fact need 1 gighertz embeded Power-PCs.
2006-04-28 by Jan Kok
On 1/22/06, Adam Seychell <a_seychell@...> wrote: > Regarding film mounting, it is ideal to have the film placed on the > inside of a drum cylinder. Maybe - there might be a problem at the edges of the film (that are parallel to the axis of the cylinder), where the film might become flat and not press against the inside of the cylinder. Also, might have to tape the film inside, to avoid it sliding around. > The drawback with this approach is building > single sided bearing mount system for the drum. I guess thats all up to > degree of mechanical balancing. Could have a conical plug that goes in one end of the cylinder. The plug would have a bearing, and the plug/bearing assembly could be mounted with a hinge to the baseplate. That allows the plug to be removed from the cylinder so you can get at the inside of the cylinder. But that doesn't sound like it is worth the trouble. For good, cheap small ball bearings, check out the bearings for rollerblades. Cheers, - Jan
2006-05-02 by Andrew
> > Roger Lucas wrote: > > I am just starting to try to figure out BMP to raster > > for the PCB EDM MILL for which I have just finished > > the drive electronics <SNIP> > > > > Are you dumping the BMP file to > > a separate micro or driving an interface direcly from > > the PC? <SNIP> > Andrewm with the goat blood on his hands wrote: > <Snip marraige proposals> > I am dumping the BMP file to a seperate Micro. > <Snip> > The idea is to have the ATMEL sit on a seriel port, > then you run some terminal software on the PC and > xmodem transfer the file to it. > <Snip> > I was going to use TIFF file format with G3 fax > compression instead of BMP. On most PCB files you will > get about a 10:1 compression ratio with G3. > <snip> > Worst case senario and I can't get an atmel to decode > G3 fax - I will hang my head in shame, do my own > RLE compression in software on the PC side and admit > to the world in general that pop-up-toasters do in > fact need 1 gighertz embeded Power-PCs. I am surprised no one quiped that a 1 Ghz CPU in a toaster could be the heating element. ANYWAYS - point of the post. Mr Roger Lucas, I have finished reading the TIFF specifications carefully and also looked at some TIFF/G3 files in a hex editor. It is very doable from a seriel stream as long as the saving application does not put the segments of the picture out of order. Most of the apps I have looked at so far have saved the TIFF in a suitable format. I will over the next few weeks cut-paste/write atmel code to: - Act as a terminal - Accept an X-Modem-CRC/128 file transfer - Decode the TIFF header info and report if the file is suitable - Decompress the RLE/Huffman data into a stream of black and white pixels If your EDM hardware uses an ATMEL you are more than welcome to the code. Even if you use another micro you might like to look at the flow/logic/ pseudo/comments to see if you want to convert the thing to run on your micro.
2006-05-02 by Herbert E. Plett
I am already looking forward to it... --- Andrew <andrewm1973@...> wrote: ... > I will over the next few weeks cut-paste/write > atmel code to: > > - Act as a terminal > - Accept an X-Modem-CRC/128 file transfer > - Decode the TIFF header info and report if the > file is suitable > - Decompress the RLE/Huffman data into a stream > of black and white pixels > > If your EDM hardware uses an ATMEL you are more > than welcome to the code. Even if you use another > micro you might like to look at the flow/logic/ > pseudo/comments to see if you want to convert the > thing to run on your micro. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
2006-05-02 by Andrew
> Me wrote: > > I have finished reading the TIFF specifications > carefully and also looked at some TIFF/G3 files in > a hex editor. It is very doable from a seriel > stream as long as the saving application does not > put the segments of the picture out of order. > > Most of the apps I have looked at so far have saved > the TIFF in a suitable format. Well - The good news and bad news. The good news is I wrote a quick and dirty TIFF file decoding application in C on the PC this afternoon. The bad news is - MANY TIFF files have the image description AFTER the pixel data. This puts a spanner in my plans to just X-Modem the file to the Plotter/EDM machine. Does Roger or anyone else that may have wanted to use this code have a preference for either of the below options 1, Write some PC code the re-saves the TIFF with the image descriptor at the start of the file Then send this re-saved TIFF via X-Modem. 2, Write some code on the PC that just reads a BMP or TIFF and sends it straight to the target system byte by byte. Option one is probably my preference. I can still just use X-Modem. The re-saved TIFF is still a valid TIFF. If your application saves in that format anyways - there is no extra step. Option two means I have to write more PC code than I normally like too - lazy lazy andrew.
2006-05-02 by roger lucas
Andrew,
I am very interested in your approach, code etc etc,
although I will probably use a PIC for the raster
handling since I already have a PIC controlling the 3
axes and the spark control. I never thought of the
TIFF format. Please post anything you develop, all
will be gratefully received.
Roger
--- Andrew <andrewm1973@...> wrote:
> Andrewm with the goat blood on his hands wrote:
> <Snip marraige proposals>
> I am dumping the BMP file to a seperate Micro.
> <Snip>
> The idea is to have the ATMEL sit on a seriel port,
> then you run some terminal software on the PC and
> xmodem transfer the file to it.
> <Snip>
> I was going to use TIFF file format with G3 fax
> compression instead of BMP. On most PCB files you
will
> get about a 10:1 compression ratio with G3.
> <snip>
> Worst case senario and I can't get an atmel to
decode
> G3 fax - I will hang my head in shame, do my own
> RLE compression in software on the PC side and admit
> to the world in general that pop-up-toasters do in
> fact need 1 gighertz embeded Power-PCs.
I am surprised no one quiped that a 1 Ghz CPU in a
toaster could be the heating element.
ANYWAYS - point of the post.
Mr Roger Lucas,
I have finished reading the TIFF specifications
carefully and also looked at some TIFF/G3 files in
a hex editor. It is very doable from a seriel
stream as long as the saving application does not
put the segments of the picture out of order.
Most of the apps I have looked at so far have saved
the TIFF in a suitable format.
I will over the next few weeks cut-paste/write
atmel code to:
- Act as a terminal
- Accept an X-Modem-CRC/128 file transfer
- Decode the TIFF header info and report if the
file is suitable
- Decompress the RLE/Huffman data into a stream
of black and white pixels
If your EDM hardware uses an ATMEL you are more
than welcome to the code. Even if you use another
micro you might like to look at the flow/logic/
pseudo/comments to see if you want to convert the
thing to run on your micro.
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Hi Andrew, > The good news is I wrote a quick and dirty TIFF > file decoding application in C on the PC this > afternoon. Just an FYI. I've used the libtiff library (www.libtiff.org) on previous projects and it seems to work quite well. It also has lots of utilities for manipu;ating TIFF files (compressing/uncompressing, resizing, etc). -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/
2006-05-02 by roger lucas
Andrew,
I have just completed some EDM tests (see separate
post), and certain requirements have come to light
which means that ideally I would like to read a BMP
and send it to the target byte by byte, (I need to add
extra commands after certain sequences of OFF pixels
in the target processor).
Sorry if this causes extra work, I know how difficult
it can be in the land of the Amber Nectar to motivate
oneself after lunch. LOL.
Roger
--- Andrew <andrewm1973@...> wrote:
> Me wrote:
>
> I have finished reading the TIFF specifications
> carefully and also looked at some TIFF/G3 files in
> a hex editor. It is very doable from a seriel
> stream as long as the saving application does not
> put the segments of the picture out of order.
>
> Most of the apps I have looked at so far have saved
> the TIFF in a suitable format.
Well - The good news and bad news.
The good news is I wrote a quick and dirty TIFF
file decoding application in C on the PC this
afternoon.
The bad news is - MANY TIFF files have the image
description AFTER the pixel data.
This puts a spanner in my plans to just X-Modem
the file to the Plotter/EDM machine.
Does Roger or anyone else that may have wanted
to use this code have a preference for either of
the below options
1, Write some PC code the re-saves the TIFF with
the image descriptor at the start of the file
Then send this re-saved TIFF via X-Modem.
2, Write some code on the PC that just reads a
BMP or TIFF and sends it straight to the
target system byte by byte.
Option one is probably my preference. I can
still just use X-Modem. The re-saved TIFF is
still a valid TIFF. If your application saves
in that format anyways - there is no extra step.
Option two means I have to write more PC code
than I normally like too - lazy lazy andrew.
Be sure to visit the group home and check for new
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them here:
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Win tickets to the 2006 FIFA World Cup Germany with Yahoo! Messenger. http://advision.webevents.yahoo.com/fifaworldcup_uk/2006-05-02 by roger lucas
Well, I finally motivated myself this holiday weekend to get my PCB EDM lash-up to cut copper, and, YES, it does cut clean lines thru the copper without board burning or marking. Shine a torch through the tracks from the rear of the board and there is a faithful line of light, (no firstborn goats or pentagrams neccessary). With my highest power lens and head magnifier I could see no trace of copper whiskers on the EDM'd track. Interestingly, the copper is blasted away entirely below the cross section of the wire, there is no 'erosion bleeding' into the surrounding copper outside of the wire dia. Have only cut straight lines so far with 26 swg and with a 0.2 mm step increment, (need to modify the stepper gear ratio), and with multiple (continuous) sparking between increments, (no on/off sparks or raster yet). One significant problem has emerged which Curt Richards did not address, (or if he did, he did not mention it). The wire electrode erosion is significant, and will require an active Z axis correction to maintain as consistent a spark gap distance as possible between the electrode and pcb surface. To do this I will insert a routine to 'touch down' the electrode on the copper to zero the gap,(no spark, closure sensed by two PIC output/inputs for voltage present), and then retreat the electrode to a standard clearance before any track eroding is commenced, (Andrew, this is why I need the BMP byte by byte transfer). This will also tend to compensate for any board distortion. Used tapwater as a dielectric with no problems, (the modified Garden of EDM circuit controls the electrolysis with no problems). Curt controlled his spark discharge voltage by dynamically adjusting the electrode gap on the fly. I think that for pcb work this is not the correct approach because of the wire erosion problem, since one needs to KNOW the gap distance AND available discharge energy BEFORE discharge, which is why I am going for the touch down zeroing method, (slower but speed is not significant at the moment). The discharge energy will be set by presetting the voltage level required and capacitor selection, (simple comparator control integrated into the spark control). I think this is the secret of successful pcb edm'ing. This is really looking as if direct raw copper board to finished pcb is going to be possible. Roger ___________________________________________________________ Yahoo! Photos \ufffd NEW, now offering a quality print service from just 7p a photo http://uk.photos.yahoo.com
2006-05-02 by Alan King
>Curt controlled his spark discharge voltage by >dynamically adjusting the electrode gap on the fly. I >think that for pcb work this is not the correct >approach because of the wire erosion problem, since >one needs to KNOW the gap distance AND available >discharge energy BEFORE discharge, which is why I am >going for the touch down zeroing method, (slower but >speed is not significant at the moment). The discharge > > Don't you want to try changing every other variable first, to see if you can eliminate the erosion problem first, then adjust everything else to match? With the same distance everything else could be just as well known with 1/4 the spark energy and 4x the rate for the same total, seems you could simply be too close for the instantanious spark energy you are using or something similar.. Only messed with EDM a few times, but I think I'd try everything under the sun first before living with the electrode eating up, even to the point of feeding blasting caps to the goats in the backyard before giving up.. Keep them away from the back wall unless you want a mess. And keep a camera handy, you will want a pic of the PETA girl's face. Also start thinking now about two electrodes. Could cut both sides with a 2 tooth tip, but independent control would be better. Raise one while traveling to make an intersection. Change the width for different traces or pads etc. And start routing everything with parallel traces and you'll be cutting one edge of two traces at once, should cut the EDM time about in half. Might even be nice for a third or fourth parallel electrode for use while the board is already under control.. Alan
2006-05-02 by lcdpublishing
VERY COOL! ;-) I am glad to hear that no goats were harmed in the production of those EDM cut PCBs :-) Chris --- In Homebrew_PCBs@yahoogroups.com, roger lucas <ralucas4277@...> wrote: > > > Well, I finally motivated myself this holiday weekend > to get my PCB EDM lash-up to cut copper, and, YES, it > does cut clean lines thru the copper without board > burning or marking. Shine a torch through the tracks > from the rear of the board and there is a faithful > line of light, (no firstborn goats or pentagrams > neccessary). > > With my highest power lens and head magnifier I could > see no trace of copper whiskers on the EDM'd track. > Interestingly, the copper is blasted away entirely > below the cross section of the wire, there is no > 'erosion bleeding' into the surrounding copper outside > of the wire dia. > > Have only cut straight lines so far with 26 swg and > with a 0.2 mm step increment, (need to modify the > stepper gear ratio), and with multiple (continuous) > sparking between increments, (no on/off sparks or > raster yet). > > One significant problem has emerged which Curt > Richards did not address, (or if he did, he did not > mention it). The wire electrode erosion is > significant, and will require an active Z axis > correction to maintain as consistent a spark gap > distance as possible between the electrode and pcb > surface. To do this I will insert a routine to 'touch > down' the electrode on the copper to zero the gap,(no > spark, closure sensed by two PIC output/inputs for > voltage present), and then retreat the electrode to a > standard clearance before any track eroding is > commenced, (Andrew, this is why I need the BMP byte by > byte transfer). This will also tend to compensate for > any board distortion. > > Used tapwater as a dielectric with no problems, (the > modified Garden of EDM circuit controls the > electrolysis with no problems). > > Curt controlled his spark discharge voltage by > dynamically adjusting the electrode gap on the fly. I > think that for pcb work this is not the correct > approach because of the wire erosion problem, since > one needs to KNOW the gap distance AND available > discharge energy BEFORE discharge, which is why I am > going for the touch down zeroing method, (slower but > speed is not significant at the moment). The discharge > energy will be set by presetting the voltage level > required and capacitor selection, (simple comparator > control integrated into the spark control). I think > this is the secret of successful pcb edm'ing. > > This is really looking as if direct raw copper board > to finished pcb is going to be possible. > > Roger > > > > > ___________________________________________________________ > Yahoo! Photos NEW, now offering a quality print service from just 7p a photo http://uk.photos.yahoo.com >
2006-05-02 by Stefan Trethan
Good to hear you got such good results. I don't have any specific concerns why it would not work, never had after some manual tests with a simple power supply. But i don't currently have the time to build a CNC, although i have most components set aside for a while now. The electrode erosion thing was discussed back then, if i remember correctly the thinking was that one would advance the electrode until a spark of the correct voltage is occuring. One would need to decide if the energy was sufficient to blast out the pixel or if it must be re-done. But your approach seems a good idea also. Keep us updated, i definitely plan to build the CNC but it will be months for sure. If i use it for drilling of inkjet printed PCBs or if EDM will be an option is to be seen. what material is your electrode wire made of? ST On Tue, 02 May 2006 18:07:19 +0200, roger lucas <ralucas4277@...> wrote:
> Well, I finally motivated myself this holiday weekend > > to get my PCB EDM lash-up to cut copper, and, YES, it > > does cut clean lines thru the copper without board > > burning or marking. Shine a torch through the tracks > > from the rear of the board and there is a faithful > > line of light, (no firstborn goats or pentagrams > > neccessary). > > > With my highest power lens and head magnifier I could > > see no trace of copper whiskers on the EDM'd track. > > Interestingly, the copper is blasted away entirely > > below the cross section of the wire, there is no > > 'erosion bleeding' into the surrounding copper outside > > of the wire dia. > > > Have only cut straight lines so far with 26 swg and > > with a 0.2 mm step increment, (need to modify the > > stepper gear ratio), and with multiple (continuous) > > sparking between increments, (no on/off sparks or > > raster yet). > > > One significant problem has emerged which Curt > > Richards did not address, (or if he did, he did not > > mention it). The wire electrode erosion is > > significant, and will require an active Z axis > > correction to maintain as consistent a spark gap > > distance as possible between the electrode and pcb > > surface. To do this I will insert a routine to 'touch > > down' the electrode on the copper to zero the gap,(no > > spark, closure sensed by two PIC output/inputs for > > voltage present), and then retreat the electrode to a > > standard clearance before any track eroding is > > commenced, (Andrew, this is why I need the BMP byte by > > byte transfer). This will also tend to compensate for > > any board distortion. > > > Used tapwater as a dielectric with no problems, (the > > modified Garden of EDM circuit controls the > > electrolysis with no problems). > > > Curt controlled his spark discharge voltage by > > dynamically adjusting the electrode gap on the fly. I > > think that for pcb work this is not the correct > > approach because of the wire erosion problem, since > > one needs to KNOW the gap distance AND available > > discharge energy BEFORE discharge, which is why I am > > going for the touch down zeroing method, (slower but > > speed is not significant at the moment). The discharge > > energy will be set by presetting the voltage level > > required and capacitor selection, (simple comparator > > control integrated into the spark control). I think > > this is the secret of successful pcb edm'ing. > > > This is really looking as if direct raw copper board > > to finished pcb is going to be possible. > > > Roger
2006-05-02 by roger lucas
Hi Stefan, I know that it should have worked in theory, but I was surprised at how well it actually turned out. I tried with tinned copper wire and a tinned steel sewing needle (purloined from my wife's needlework box), essentially the wear was about the same for both. The eroded pixel diameter is directly related to the electrode dia, as the sewing needle eroded the pixel became larger. I need to try to obtain some half hard or hard 10 mil brass wire for the next trial. The setting of the spark parameters before sparking is essentially to eliminate the uncertainty of whether pixels have been fully eroded or not, especially where electrode wear is high. I might just try some broken carbide drill bits, the tungsten might resist erosion better, trouble is carbide only goes to 0.5mm dia. Will post some sample photos after next revision and trials. Roger --- Stefan Trethan <stefan_trethan@...> wrote: > Good to hear you got such good results. > > I don't have any specific concerns why it would not > work, never had after > some manual tests with a simple power supply. > > But i don't currently have the time to build a CNC, > although i have most > components set aside for a while now. > > The electrode erosion thing was discussed back then, > if i remember > correctly the thinking was that one would advance > the electrode until a > spark of the correct voltage is occuring. One would > need to decide if the > energy was sufficient to blast out the pixel or if > it must be re-done. > But your approach seems a good idea also. > > Keep us updated, i definitely plan to build the CNC > but it will be months > for sure. If i use it for drilling of inkjet printed > PCBs or if EDM will > be an option is to be seen. > > what material is your electrode wire made of? > > ST > > > On Tue, 02 May 2006 18:07:19 +0200, roger lucas > <ralucas4277@...> > wrote: > > > Well, I finally motivated myself this holiday > weekend ___________________________________________________________ Win tickets to the 2006 FIFA World Cup Germany with Yahoo! Messenger. http://advision.webevents.yahoo.com/fifaworldcup_uk/
2006-05-02 by Codesuidae
roger lucas wrote: > I know that it should have worked in theory, but I was > surprised at how well it actually turned out. What is the linear feedrate for this? Or, alternatively, about how many square cm of copper are removed per minute? Dave K
2006-05-02 by Stefan Trethan
We were even considering a rotating electrode and a diamond wheel "automatic sharpening station" back then. Try graphite, they use it for EDM sinkers. Probably a continous feed wire is easier than all that, but it would need to be pretty thin wire to get any decent resolution. ST On Tue, 02 May 2006 19:57:22 +0200, roger lucas <ralucas4277@...> wrote:
> Hi Stefan, > > > I know that it should have worked in theory, but I was > > surprised at how well it actually turned out. > > > I tried with tinned copper wire and a tinned steel > > sewing needle (purloined from my wife's needlework > > box), essentially the wear was about the same for > > both. The eroded pixel diameter is directly related to > > the electrode dia, as the sewing needle eroded the > > pixel became larger. > > I need to try to obtain some half hard or hard 10 mil > > brass wire for the next trial. > > > The setting of the spark parameters before sparking is > > essentially to eliminate the uncertainty of whether > > pixels have been fully eroded or not, especially where > > electrode wear is high. I might just try some broken > > carbide drill bits, the tungsten might resist erosion > > better, trouble is carbide only goes to 0.5mm dia. > > > Will post some sample photos after next revision and > > trials. > > > Roger
2006-05-02 by Stefan Trethan
Electrode erosion is quite normal with EDM, it is not a fault as such that can be eliminated. Probably can be reduced though.. ST
On Tue, 02 May 2006 18:50:19 +0200, Alan King <alan@...> wrote: > Don't you want to try changing every other variable first, to see if > > you can eliminate the erosion problem first, then adjust everything else > > to match? With the same distance everything else could be just as well > > known with 1/4 the spark energy and 4x the rate for the same total, > > seems you could simply be too close for the instantanious spark energy > > you are using or something similar..
2006-05-02 by lcdpublishing
Roger, I am not real familiar with EDM, but I do recall that the two materials used for electrodes were carbon (for sinker types) and Brass for Wire EDMs. In the case of what you are doing, it fits into the realm of a sinker type EDM. I vaguely recall them using a sinker EDM machine to drill some small holes in some very hard metal. I believe they used a carbon electrode for that too. Sorry I can't offer more, it was about 18 years ago I was involved with that company and no longer have any contacts in the EDM field. Chris > Roger > > --- Stefan Trethan <stefan_trethan@...> wrote: > > > Good to hear you got such good results. > > > > I don't have any specific concerns why it would not > > work, never had after > > some manual tests with a simple power supply. > > > > But i don't currently have the time to build a CNC, > > although i have most > > components set aside for a while now. > > > > The electrode erosion thing was discussed back then, > > if i remember > > correctly the thinking was that one would advance > > the electrode until a > > spark of the correct voltage is occuring. One would > > need to decide if the > > energy was sufficient to blast out the pixel or if > > it must be re-done. > > But your approach seems a good idea also. > > > > Keep us updated, i definitely plan to build the CNC > > but it will be months > > for sure. If i use it for drilling of inkjet printed > > PCBs or if EDM will > > be an option is to be seen. > > > > what material is your electrode wire made of? > > > > ST > > > > > > On Tue, 02 May 2006 18:07:19 +0200, roger lucas > > <ralucas4277@...> > > wrote: > > > > > Well, I finally motivated myself this holiday > > weekend > > > > > > > ___________________________________________________________ > Win tickets to the 2006 FIFA World Cup Germany with Yahoo! Messenger. http://advision.webevents.yahoo.com/fifaworldcup_uk/ >
2006-05-02 by javaguy11111
Since some have suggested carbon electrodes you might try .3mm or .5mm mechanical pencil leads. I have no way of knowing if they would be appropriate,but might be worth a try. You should be able to find .3mm leads at an art or architectural supply store. --- In Homebrew_PCBs@yahoogroups.com, roger lucas <ralucas4277@...> wrote: > > Hi Stefan, > > I know that it should have worked in theory, but I was > surprised at how well it actually turned out. > > I tried with tinned copper wire and a tinned steel > sewing needle (purloined from my wife's needlework > box), essentially the wear was about the same for > both. The eroded pixel diameter is directly related to > the electrode dia, as the sewing needle eroded the > pixel became larger. > I need to try to obtain some half hard or hard 10 mil > brass wire for the next trial. > > The setting of the spark parameters before sparking is > essentially to eliminate the uncertainty of whether > pixels have been fully eroded or not, especially where > electrode wear is high. I might just try some broken > carbide drill bits, the tungsten might resist erosion > better, trouble is carbide only goes to 0.5mm dia. > > Will post some sample photos after next revision and > trials. > > Roger > > --- Stefan Trethan <stefan_trethan@...> wrote: > > > Good to hear you got such good results. > > > > I don't have any specific concerns why it would not > > work, never had after > > some manual tests with a simple power supply. > > > > But i don't currently have the time to build a CNC, > > although i have most > > components set aside for a while now. > > > > The electrode erosion thing was discussed back then, > > if i remember > > correctly the thinking was that one would advance > > the electrode until a > > spark of the correct voltage is occuring. One would > > need to decide if the > > energy was sufficient to blast out the pixel or if > > it must be re-done. > > But your approach seems a good idea also. > > > > Keep us updated, i definitely plan to build the CNC > > but it will be months > > for sure. If i use it for drilling of inkjet printed > > PCBs or if EDM will > > be an option is to be seen. > > > > what material is your electrode wire made of? > > > > ST > > > > > > On Tue, 02 May 2006 18:07:19 +0200, roger lucas > > <ralucas4277@...> > > wrote: > > > > > Well, I finally motivated myself this holiday > > weekend > > > > > > > ___________________________________________________________ > Win tickets to the 2006 FIFA World Cup Germany with Yahoo! Messenger. http://advision.webevents.yahoo.com/fifaworldcup_uk/ >
2006-05-02 by Lez
or mallwart >. You should be able to find .3mm > leads at an art or architectural supply store.
2006-05-02 by Alan King
Stefan Trethan wrote: >Electrode erosion is quite normal with EDM, it is not a fault as such that >can be eliminated. > >Probably can be reduced though.. > > > Yep hadn't thought on it in a while, but doesn't look like much you can do beyond having the electrode negative and spark power etc. If only you could keep the electrode very cold and the board very hot for different vaporization energies, but wouldn't be easy. Heck wire is cheap anyway.. Your wheel got me thinking on a disc, a thin copper washer on a Dremel arbor would have much larger edge area. Spin it some and it'd last a long time with little change in gap, a little less precise in the long direction but that's the way of travel. But directional, wire isn't, and again heck it's cheap make a feed system and throw more at it. .2mm pencil lead might be an option too on the graphite end of things.. For this, an HP Plotter may be a good choice too, no real need for CNC power. HPGL is so flexible you may even get to the low feed rates needed just from the language.. Of course I just threw mine away with the older inkjets in the last round. Useful but way too bulky when not using, and easy to replace for $10 or $20 here or there. Didn't even junk them this time, too much work for a few motors. Alan
2006-05-02 by Robert Hedan
A short video would be ever so cool for nerds like me who have never seen this type of machine. I can host it for you for a while too. Robert :) > -----Message d'origine----- > De : Homebrew_PCBs@yahoogroups.com > [mailto:Homebrew_PCBs@yahoogroups.com] De la part de roger lucas > Envoyé : mai 2 2006 13:57 > À : Homebrew_PCBs@yahoogroups.com > Objet : Re: [Homebrew_PCBs] PCB EDM MILL Initial Tests > > ...
> > Will post some sample photos after next revision and > trials. > > Roger >
2006-05-02 by Andrew
> Roger wrote: > I have just completed some EDM tests (see separate > post), and certain requirements have come to light > which means that ideally I would like to read a BMP > and send it to the target byte by byte, (I need to add > extra commands after certain sequences of OFF pixels > in the target processor). > > Sorry if this causes extra work, I know how difficult > it can be in the land of the Amber Nectar to motivate > oneself after lunch. LOL. No problems. BMP files are pretty easy to read. I will have a play around with them in the next few days. For my purposes - I will still need to compress them (G3 my pref) just to get them down to the plotter in under 4 hours. I don't quite understand the "motivate onesself after lunch" comment. Is this "lunch" you refer to something about 1/2 way through the day that we call "Rum o'clock" :D
2006-05-03 by Andrew
> Dave H wrote: > > I've used the libtiff library > (www.libtiff.org) on previous projects and > it seems to work quite well. It also has > lots of utilities for manipu;ating TIFF > files (compressing/uncompressing, resizing, > etc). Thanks - I suspected that there would be 1001 free librarys on the PC to do tiff. I wanted to try decode it myself so I knew I could re-write the code in an Atmel. Now I am going to be reading the TIFF on the PC for the final product - I will have a look at the www.libtiff.org - thanks.
2006-05-03 by Andrew
> roger lucas wrote: <BIG snip> > This is really looking as if direct raw copper board > to finished pcb is going to be possible. YAY
2006-05-03 by Andrew
> lcdpublishing wrote:
>
> VERY COOL! ;-) I am glad to hear that
> no goats were harmed in the production
> of those EDM cut PCBs :-)
AND
> AlanK wrote:
>
> even to the point of feeding blasting
> caps to the goats in the backyard before
> giving up.. Keep them away from the back
> wall unless you want a mess. And keep a
> camera handy, you will want a pic of the
> PETA girl's face.
But what will I do with unused goats if
the wire EDM works sans goats ?
andrewm - I'd rather be nekkid than wear
a thin film of goat blood.2006-05-03 by Andrew
> AlanK wrote: > > Also start thinking now about two > electrodes. Could cut both sides with > a 2 tooth tip, but independent control > would be better. I don't understand why independant control would be advantagous. The EDM was going to be done raster not vector. However - I agree that extra wires would be cool. Make it like a 24 pin dot matrix printer (pins offset so they dont inter-pin-spark) Knock out an EDM in pages per minute rather than minutes per page. I knew there was a reason I wanted 3 phase power in my shed :D
2006-05-03 by Dave Hylands
Hi Andrew, > For my purposes - I will still need to compress them > (G3 my pref) just to get them down to the plotter in > under 4 hours. G4 should give even better compression. It requies a bit more memory to decompress since you need to use the previous line as a reference line. -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/
2006-05-03 by Chris Horne
Roger, how small do you need to go ? probaly smaller than 0.6mm.. pity.. 0.6mm Mig welding wire is cheap stiff and freely available. Mild Steel would be the obvious choice, it also has a nice copper coating for electrical connection, and the design for the feed mechanism used in mig welders could possibly also be used (Two rollers, one with a groove in it, much slower of course) Chris --- In Homebrew_PCBs@yahoogroups.com, roger lucas <ralucas4277@...> wrote:
> > Hi Stefan, > > I know that it should have worked in theory, but I was > surprised at how well it actually turned out. > > I tried with tinned copper wire and a tinned steel > sewing needle (purloined from my wife's needlework > box), essentially the wear was about the same for >
2006-05-03 by Andrew
> Roger wrote: > > I am very interested in your approach, code > etc etc, although I will probably use a PIC > for the raster handling since I already have > a PIC controlling the 3 axes and the spark > control. I never thought of the TIFF format. > Please post anything you develop, all will > be gratefully received. Roger - I missed this part in the TIFF FAQ <Quote from a TIFF faq> Question 7. Can I not stream TIFF? Why does my library need seeking forward and backward in my TIFF file? TIFF is not a streamable format. It is its very nature that all data blocks can be written in any order that is convenient for the particular application and/or TIFF encoding library. </Quote> The first TIFFs I looked at where suitable for streaming. They had the information header in front of the actual picture data. However the main app I use, and I guess a lot of people do, is irfanview. It saves TIFF with the header at the end of the file. Many other apps probably do the same. This just can't work for the plotter (or I guess for your EDM). This is because the ATMEL (or PIC) does not have enough memory to hold the whole file. It has to burn each line as it receives it and then discard that data to buffer the next line. Problem here is that you don't get to find out things like how wide and how long the file is in pixels until you get to the end of it. BMP is a much more strictly organised file structure and always has the picture info in front of the picture. It is an absolute doddle to read. The draw back of BMP is that there is no compression. a 12 inch by 6 inch 2000 DPI black and white BMP will be 35 megabytes. At 115200 baud if you take into account overheads of a UART, X-Modem and the like you end up with a 63 minute transfer. Even at 1 megabaud it takes 7 minutes. 7 minutes IS within the time limit I would like a plot to come out, but receiving at 1 megabaud is going to be a bigger strain on resources of the ATMEL than if it where to be run length compressed. It would be easier for me to receive a 3.5 megabyte file and decompress it on the fly than receiving 35 meg. The EDM requirments are probably not as bad. I would probably guess 500 dpi (0.05mm) would be your highest res. However it would still probably be easier for your PIC to receive and do the CRC of a smaller file and then decompress an easy scheme like G3 or PackBits. Tell me what you think? I am now thinking - Read BMP file in PC software. - Get PC to compress and send to ATMEL or PIC in X-Modem-CRC format. - Atmel decompresses to actual raster data.
2006-05-03 by Andrew
> DaveH wrote: > > G4 should give even better compression. > It requies a bit more memory to > decompress since you need to use the > previous line as a reference line. > Yeah - I looked at G4 - it does about 25% to 50% better compression on pictures that look like PCBs. I was however planning on using an atmel with only 8K of ram. If I had to put any external chips on the thing to make it meet the specs I will probably just say bugger it. Get an ARM, put oddles of RAM run *nix on it and FTP the file stragiht to it. When the cat (or goat) gets too big to skin wih a knife - you resort to high explosives.
2006-05-03 by curt_rxr
--- In Homebrew_PCBs@yahoogroups.com, roger lucas <ralucas4277@...> wr wrote: Well done Roger! > One significant problem has emerged which Curt > Richards did not address, (or if he did, he did not > mention it). The wire electrode erosion is > significant, and will require an active Z axis > correction to maintain as consistent a spark gap > distance as possible between the electrode and pcb > surface. Roger I used brass wire and distilled water and had arranged the servo circuit to feed the wire via a pinch roller and worm screw drive. the servo circuit is as per the NASA / Garden of EDM circuit. > > Curt controlled his spark discharge voltage by > dynamically adjusting the electrode gap on the fly. I > think that for pcb work this is not the correct > approach because of the wire erosion problem, since > one needs to KNOW the gap distance AND available > discharge energy BEFORE discharge, which is why I am > going for the touch down zeroing method, (slower but > speed is not significant at the moment). Roger the gap breakdown voltage controls the gap via the servo. As the electrode ( brass wire ) advances the gap closes until the spark after which the electrode retracts so the system is ready for he next spark. > The discharge > energy will be set by presetting the voltage level > required and capacitor selection, (simple comparator > control integrated into the spark control). I think > this is the secret of successful pcb edm'ing. > > This is really looking as if direct raw copper board > to finished pcb is going to be possible. > > Roger > Hi Roger, I'm glad to see someone making progress. My system is stalled at a pulse repetition rate of 200,000 per second using IGBTs designed for auto igniton system. That rate gives me about an hour and a quarter pocessing time for an 8 inch by 12 inch PCB using .001 inch brass wire as an electrode. It makes a real nice board, but I can use Toner Transfer and CuCl2 bubble etching to make five boards in the same time! I'll be interested in your advances to the art, but right now it looks to me like the direct print inkjet system will replace TT and EDM for homebrew PCB prototyping. Curt Richards
2006-05-03 by Andrew
> Curt AND Roger wrote - lots about EDM.... > Curt then wrote : > > <SNIP> > using IGBTs designed for auto igniton > system. That rate gives me about an > hour and a quarter pocessing time for > an 8 inch by 12 inch PCB using .001 > inch brass wire as an electrode. It > makes a real nice board, but I can use > Toner Transfer and CuCl2 bubble etching > to make five boards in the same time! > > I'll be interested in your advances to > the art, but right now it looks to me > like the direct print inkjet system > will replace TT and EDM for homebrew > PCB prototyping. I was wondering if either Curt or Roger would be willing to shre their circuits with others. Some of us are a little bit lazy and have a little to much other stuff to design. An RTFM build would be greatly appreciated. Even if it was less than optimal. I also don't know how fast the EDM PCB could run. But I did a quick (stupid) test with my fronius magicwave 180 amp tig welder. I couldn't get 6 thou trck spacing - but MY was the copper removal rate fast :D:D:D
2006-05-03 by Russell Shaw
Andrew wrote: >>Roger wrote: >> >>I am very interested in your approach, code >>etc etc, although I will probably use a PIC >>for the raster handling since I already have >>a PIC controlling the 3 axes and the spark >>control. I never thought of the TIFF format. >>Please post anything you develop, all will >>be gratefully received. > > > Roger - I missed this part in the TIFF FAQ > > <Quote from a TIFF faq> > > Question 7. Can I not stream TIFF? Why does my > library need seeking forward and backward in > my TIFF file? > > TIFF is not a streamable format. It is its > very nature that all data blocks can be > written in any order that is convenient for > the particular application and/or TIFF > encoding library. > > </Quote> > > The first TIFFs I looked at where suitable > for streaming. They had the information > header in front of the actual picture data. > > However the main app I use, and I guess a lot > of people do, is irfanview. It saves TIFF > with the header at the end of the file. > Many other apps probably do the same. > > This just can't work for the plotter (or I > guess for your EDM). This is because the > ATMEL (or PIC) does not have enough memory > to hold the whole file. It has to burn each > line as it receives it and then discard that > data to buffer the next line. > > Problem here is that you don't get to find > out things like how wide and how long the > file is in pixels until you get to the end > of it. Just get the PC to re-order the file before sending it. Decent software decomposes the data (in whatever image format) to specialized control instructions for the machine anyway.
2006-05-03 by Andrew
> > andrewm wrote:
> > Problem here is that you don't get to find
> > out things like how wide and how long the
> > file is in pixels until you get to the end
> > of it.
> Russel wrote:
> Just get the PC to re-order the file before
> sending it.
The original plan was to not have to write
ANY software on the PC ('cause we all hate
doing that).
It was just going to be use hyper terminal to
send the TIFF file to the plotter/EDM unit.
(X-Modem-CRC)
Seeing as we can't be sure that a TIFF file
is written in order - I HAVE to write some PC
software.
Either software to read a TIFF and re-order
it so it can be sent OR software to just
read a BMP/TIFF and send it to the plotter
myself (without hyper terminal)
> Decent software decomposes the data (in
> whatever image format) to specialized control
> instructions for the machine anyway.
A Decent machine doesn't need specialised
control instructions. It just reads a native
file from the control source :D
Seeing as my machine does not have enough
memory to read an abitary TIFF or enough
bandwidth to read a BMP. I am going to
have to compromise and only have a 1/2
decent machine that needs some special
control instructions.2006-05-03 by Russell Shaw
Andrew wrote:
>>>andrewm wrote:
>>>Problem here is that you don't get to find
>>>out things like how wide and how long the
>>>file is in pixels until you get to the end
>>>of it.
>
>>Russel wrote:
>>Just get the PC to re-order the file before
>>sending it.
>
>
> The original plan was to not have to write
> ANY software on the PC ('cause we all hate
> doing that).
>
> It was just going to be use hyper terminal to
> send the TIFF file to the plotter/EDM unit.
> (X-Modem-CRC)
>
> Seeing as we can't be sure that a TIFF file
> is written in order - I HAVE to write some PC
> software.
>
> Either software to read a TIFF and re-order
> it so it can be sent OR software to just
> read a BMP/TIFF and send it to the plotter
> myself (without hyper terminal)
>
>
>>Decent software decomposes the data (in
>>whatever image format) to specialized control
>>instructions for the machine anyway.
>
> A Decent machine doesn't need specialised
> control instructions. It just reads a native
> file from the control source :D
Most "real" machines read G-code, that has been
generated from the original CAD data such as DXF
(gerber is G-codes).
By converting all external data types to one format
suited to the machine, machine complexity is minimized.
> Seeing as my machine does not have enough
> memory to read an abitary TIFF or enough
> bandwidth to read a BMP. I am going to
> have to compromise and only have a 1/2
> decent machine that needs some special
> control instructions.
Even if it could read tiff, that would mean that any
other data type would need to be converted to tiff.2006-05-03 by Herbert E. Plett
--- Andrew <andrewm1973@...> wrote:
> The original plan was to not have to write
> ANY software on the PC ('cause we all hate
> doing that).
>
> It was just going to be use hyper terminal to
> send the TIFF file to the plotter/EDM unit.
> (X-Modem-CRC)
>
> Seeing as we can't be sure that a TIFF file
> is written in order - I HAVE to write some PC
> software.
what about using any 'fax' program?
the nasty thing about PC software is it has to be multi-platform these days.
the old days of 'only' M$ are over...
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http://mail.yahoo.com2006-05-03 by Russell Shaw
Herbert E. Plett wrote:
>
> --- Andrew <andrewm1973@...> wrote:
>
>>The original plan was to not have to write
>>ANY software on the PC ('cause we all hate
>>doing that).
>>
>>It was just going to be use hyper terminal to
>>send the TIFF file to the plotter/EDM unit.
>>(X-Modem-CRC)
>>
>>Seeing as we can't be sure that a TIFF file
>>is written in order - I HAVE to write some PC
>>software.
>
> what about using any 'fax' program?
>
> the nasty thing about PC software is it has to be multi-platform these days.
> the old days of 'only' M$ are over...
Multi-platform is easy as long as you exclude M$;)2006-05-03 by Andrew
>>> andrewm wrote:
>>> Seeing as we can't be sure that a
>>> TIFF file is written in order - I
>>> HAVE to write some PC software.
> > Herbert wrote:
> > what about using any 'fax' program?
I think a fax program would have a fit
if you gave it a BMP that was 12000 x
20000 dots. It is normally dealing
with files that are 204x204 DPI not
2000x2000 dpi.
> > the nasty thing about PC software
> > is it has to be multi-platform these
> > days. the old days of 'only' M$ are
> > over...
> Russell wrote:
> Multi-platform is easy as long as you
> exclude M$;)
>
Multi platform is so easy if all you
need a a terminal program someone else
wrote :D
andrewm - Who is wondering if the
russell(dot)AU is from SE Qld.2006-05-03 by Alan King
Andrew wrote: >>AlanK wrote: >> >> Also start thinking now about two >>electrodes. Could cut both sides with >>a 2 tooth tip, but independent control >>would be better. >> >> > >I don't understand why independant control >would be advantagous. The EDM was going >to be done raster not vector. > > > I didn't really read every word of the rest so may have missed something about raster, but raster would take a tremendous amount of time vs vector, and the single wire CNC setup doesn't really have a reason to go over areas that aren't etched, if it's following the cut line and in different directions it's vector regardless of being an XYZ table and keeping most of the paths X or Y.. Raster's more a fixed format scan of everywhere, not really needed for this type of thing normally. Little reason to travel uncut areas with a CNC. And you almost always have to cut the other side of the trace, whether it's an isolated trace or simply the cut between this trace and the next. Wasn't clear, that was independent control of the feed rate of both wires not different XY control, fixed or simple distance relationship. You have to control seperately anyway for different erosion rates, simpler to just back one or the other wire off where you don't want to cut than control the supply too.. Really this would be simple, and do 90% of things well with an easy enough system: o x o All three the same size, x is just the main electrode. 3 seperate feeds, two power supplies, the second attached to both of the secondary wires. Main one cuts and does the tracing, upper cuts the other side of horizontal traces, right one cuts the other side of vertical traces. Keep most of the cuts horizontal and vertical and this will let you isolate both sides of a trace at once without requiring rotation, just a second supply and seperate feed mechanisms for the three wires. Just back one of the two secondaries off or both for curves or diagonals with only the main wire.. Generally double the linear cutting rate of a single wire, with only a second power supply and 3 feeds so still not too complicated. Don't care about the width change and you could do 45 deg diagonals too, they'd just be more narrow with a fixed system. Just two supplies and 3 feeds on a CNC, may just have to try it out myself. If it can be taken down to cutting pads and traces for SOIC pitch devices it'd be great, that'd do enough for most prototyping. The real work will be automatically controlling the feed rate for erosion. With just drilling a hole, you simply look at the spark frequency and when it gets too low you feed, it's in the direction of feed. With this you have needing XY direction feed and erosion away from the board that both reduce the spark rate. No doubt figureable but not as easy.. >However - I agree that extra wires would >be cool. > >Make it like a 24 pin dot matrix printer >(pins offset so they dont inter-pin-spark) > > > Would be nice for other things even. But with differing discharge rates or on or off control that will take either or both of 24 feeds and supplies, depending on how you want to do it. Could probably hack a few motors to do it all, like a vending machine selector, but getting it all to work would probably still be not so easy.. Alan
2006-05-03 by Andrew
> Russell wrote: > Most "real" machines read G-code, that has > been generated from the original CAD data > such as DXF (gerber is G-codes). I Assume "real" means real milling machine / drilling machine or something specific to PCB or engineering. Real plotters use HP/GL Real printers use postscript or PCL Real photo-printers (often) use TIFF My photoplotter will also be used to make photo tools for screen printing. That will be inherently raster stuff rather than bitmaps. Someone else has written the software to convert gerber to bitmaps so I dont have too :D > By converting all external data types to one > format suited to the machine, machine > complexity is minimized. There are lots of different standards out there. I would have liked to use one of them rather than make up my own. > Even if it could read tiff, that would > mean that any other data type would need > to be converted to tiff. Yes - but by some software someone else has written and that is also probably already availabe cross-platform. You do understand the concept and advantages of making the machine just a terminal that accepts a file via x-modem don't you ?
2006-05-03 by Russell Shaw
Andrew wrote: >>>>andrewm wrote: >>>>Seeing as we can't be sure that a >>>>TIFF file is written in order - I >>>>HAVE to write some PC software. > >>>Herbert wrote: >>>what about using any 'fax' program? > > I think a fax program would have a fit > if you gave it a BMP that was 12000 x > 20000 dots. It is normally dealing > with files that are 204x204 DPI not > 2000x2000 dpi. > >>>the nasty thing about PC software >>>is it has to be multi-platform these >>>days. the old days of 'only' M$ are >>>over... > >>Russell wrote: >>Multi-platform is easy as long as you >>exclude M$;) >> > > Multi platform is so easy if all you > need a a terminal program someone else > wrote :D A terminal program just dumps files from the pc into the machine, which is no different if tiff or g-code is used. Another way is to have only a small buffer in the machine and download a few g-codes at a time, which should be doable with a terminal program if flow-control is used. > > andrewm - Who is wondering if the > russell(dot)AU is from SE Qld. I'm near melbourne (never been to Qld). Beware of cane toads;)
2006-05-03 by Andrew
> >andrewm wrote: > >I don't understand why independant control > >would be advantagous. The EDM was going > >to be done raster not vector. > wrote: > I didn't really read every word of the > rest so may have missed something about > raster, but raster would take a tremendous > amount of time vs vector, and the single > wire CNC setup doesn't really have a > reason to go over areas that aren't etched > ><snip> Curt and Roger where doing it raster to avoid problems of isolating copper from the GND electrod clip. If you just used a normal isolation milling CAM file (like you would with a mechanical router) then you might end up with an island of copper in the middle of the board with no ground connection. The EDN wont spark on that any more :(
2006-05-03 by Russell Shaw
Andrew wrote: >>Russell wrote: >>Most "real" machines read G-code, that has >>been generated from the original CAD data >>such as DXF (gerber is G-codes). > > I Assume "real" means real milling machine / > drilling machine or something specific to PCB > or engineering. > > Real plotters use HP/GL > Real printers use postscript or PCL > Real photo-printers (often) use TIFF Printers aren't "real" machines;) I mean milling machines, x-y laser cutters, etc. > My photoplotter will also be used to make photo > tools for screen printing. That will be > inherently raster stuff rather than bitmaps. > > Someone else has written the software to > convert gerber to bitmaps so I dont have too :D > > >>By converting all external data types to one >>format suited to the machine, machine >>complexity is minimized. > > > There are lots of different standards out > there. I would have liked to use one of > them rather than make up my own. > > >>Even if it could read tiff, that would >>mean that any other data type would need >>to be converted to tiff. > > > Yes - but by some software someone else > has written and that is also probably > already availabe cross-platform. > > You do understand the concept and > advantages of making the machine just a > terminal that accepts a file via x-modem > don't you ? Yes, but i'd use a vector format like g-code, gerber, postscript, pcl, or some forth dialect because the file size would be a thousandth of a bitmap file size. For an edm or milling machine, the vector commands can be executed directly. For a raster output device such as a scanner, the machine controller can rasterize the vector output like laser printers do with postscript.
2006-05-03 by Andrew
> The guy from victoria wrote: > > A terminal program just dumps files from > the pc into the machine, which is no > different if tiff or g-code is used. Well - In this application g-code is not suitable. If you remember the start of the thread - I am trying to make a cheap photoplotter anyone can replicate for a few $100 or so. Drum photoplotter means raster. Cheap means that I cant have enough CPU and RAM onboard to convert vector to raster internally. The board is planing on having an ATMEL, a analog PLL and not much else on it. 16 megahertz - 8 bit CPU 128K ROM 16K RAM couple of timers a UART and an SPI port. Call me a masochist I guess :D
2006-05-03 by Andrew
> rshaw wrote: > > Yes, but i'd use a vector format like > g-code, gerber, postscript, pcl, or some > forth dialect because the file size > would be a thousandth of a bitmap file > size. For an edm or milling machine, the > vector commands can be executed directly. > For a raster output device such as a > scanner, the machine controller can > rasterize the vector output like laser > printers do with postscript. Big thumbs up to vector formats. They are GREAT. But not in an ATMega1280 :D hmmmm - I wonder if I could fit it into an AT-Tiny45 ......... NOW there is a challenge for me.
2006-05-03 by Alan King
>If you just used a normal isolation milling >CAM file (like you would with a mechanical >router) then you might end up with an >island of copper in the middle of the board >with no ground connection. > >The EDN wont spark on that any more :( > > Makes sense and easy enough and probably not even that bad with an intelligent skip of uncut areas.. I'd still rather see it draw the traces with electricity, shouldn't be too hard to figure out some type of useable sort and just more fun to watch.
2006-05-03 by Russell Shaw
Andrew wrote: >>The guy from victoria wrote: >> >>A terminal program just dumps files from >>the pc into the machine, which is no >>different if tiff or g-code is used. > > > Well - In this application g-code is not > suitable. If you remember the start of the > thread - I am trying to make a cheap > photoplotter anyone can replicate for a few > $100 or so. > > Drum photoplotter means raster. > > Cheap means that I cant have enough CPU and > RAM onboard to convert vector to raster > internally. > > The board is planing on having an ATMEL, > a analog PLL and not much else on it. > > 16 megahertz - 8 bit CPU > 128K ROM > 16K RAM > couple of timers > a UART > and an SPI port. > > Call me a masochist I guess :D I got slightly confused thinking of EDM machines. At the data rates needed, you'll need to store the whole file in the machine controller. A 300mm drum has a circumference around 1000mm. Assume a pixel size of 0.01mm. If it rotates at 600rpm, the pixel rate is 1Mpixel/sec. A 100mm x 100mm plot will need 1000s or 17mins to scan. The averaged pixel rate will be 100k pixels/sec. The file size will be 100Meg pixels, which is impractical. You'll need to transfer and store the file in a vector format, and progressively rasterize it as the drum scanner needs it. If you rasterize to 1k pixels at a time, you'll only need to do that 100 times per second.
2006-05-03 by Russell Shaw
Andrew wrote: >>The guy from victoria wrote: >> >>A terminal program just dumps files from >>the pc into the machine, which is no >>different if tiff or g-code is used. > > > Well - In this application g-code is not > suitable. If you remember the start of the > thread - I am trying to make a cheap > photoplotter anyone can replicate for a few > $100 or so. > > Drum photoplotter means raster. > > Cheap means that I cant have enough CPU and > RAM onboard to convert vector to raster > internally. > > The board is planing on having an ATMEL, > a analog PLL and not much else on it. > > 16 megahertz - 8 bit CPU > 128K ROM > 16K RAM > couple of timers > a UART > and an SPI port. > > Call me a masochist I guess :D I got slightly confused thinking of EDM machines. At the data rates needed, you'll need to store the whole file in the machine controller. A 300mm drum has a circumference around 1000mm. Assume a pixel size of 0.01mm. If it rotates at 600rpm, the pixel rate is 1Mpixel/sec. A 100mm x 100mm plot will need 1000s or 17mins to scan. The averaged pixel rate will be 100k pixels/sec. The file size will be 100Meg pixels, which is impractical. You'll need to transfer and store the file in a vector format, and progressively rasterize it as the drum scanner needs it. If you rasterize to 1k pixels at a time, you'll only need to do that 100 times per second. The pc could send bitmap data while the machine is running, if the data rate is higher than 100k bits/sec. Fast rs-232, usb, or ethernet could do that.
2006-05-03 by Andrew
> >I wrote: > >If you just used a normal isolation milling > >CAM file (like you would with a mechanical > >router) then you might end up with an > >island of copper in the middle of the board > >with no ground connection. > > > >The EDN wont spark on that any more :( > Alan wrote: > > Makes sense and easy enough and probably > not even that bad with an intelligent skip > of uncut areas.. I'd still rather see it > draw the traces with electricity, shouldn't > be too hard to figure out some type of > useable sort and just more fun to watch. It would be an easy enough algorithm to to get all the vectors from the G-Code and z-sort them to avoid islands. But we are going to get back into the writing PC software argument again if we do :D I think the 24/32 wire EDM printer might win in a race with a vector one at the end of the day anyways.
2006-05-03 by Andrew
> Russell wrote: > > At the data rates needed, you'll need > to store the whole file in the machine > controller. I was only planning on storing 1 row/ scanline of data at a time. > A 300mm drum has a circumference around > 1000mm. Assume a pixel size of 0.01mm. > If it rotates at 600rpm, the pixel rate > is 1Mpixel/sec. A 100mm x 100mm plot > will need 1000s or 17mins to scan. The > averaged pixel rate will be 100k pixels > /sec. The file size will be 100Meg > pixels, which is impractical. > The pc could send bitmap data while the > machine is running, if the data rate is > higher than 100k bits/sec. Fast rs-232, > usb, or ethernet could do that. I was planing on a 16.384 inch active area on a 20 inch or so round drum that is 10 inches long. (no prizes for guessing why I chose the active area to be 16.384 inches) 2000 dpi (about 0.01mm) resolution. It ends up being a file size of 35 megabytes. I think the data rate I worked out I wanted was 800 kilo baud RAW. An FT232 sitting on a USB port can do this. But its going to be a strain on the poor Atmel to keep the throughput. Most PCB files compress better than 10:1 with G3. If I G3 compress it I can get by with much lower baud rates (sub 100 kilobaud) CRC on a 1 megabaud link will take more time than CRC on a 100kilobaud link and G3 decompression together. I think the ATMEL has enough omph for either - but i like the idea of keeping horsepower spare in case I find there is something else I need to do. Worst case senario and I am prting out a bit map for a T-Shirt and I don't get 10:1 compression - it just runs slow. Because the atmel has enough memory to buffer one full scan line - it wont BREAK the thing - it just will mean it has to pause between scanlines. (one hour to print instead of 10 minutes)
2006-05-03 by curt_rxr
--- In Homebrew_PCBs@yahoogroups.com, "Andrew" <andrewm1973@...> wrote: > > > >I wrote: > > >If you just used a normal isolation milling > > >CAM file (like you would with a mechanical > > >router) then you might end up with an > > >island of copper in the middle of the board > > >with no ground connection. > > > > > >The EDN wont spark on that any more :( > > > Alan wrote: > > > > Makes sense and easy enough and probably > > not even that bad with an intelligent skip > > of uncut areas.. I'd still rather see it > > draw the traces with electricity, shouldn't > > be too hard to figure out some type of > > useable sort and just more fun to watch. > > > It would be an easy enough algorithm to to > get all the vectors from the G-Code and > z-sort them to avoid islands. But we are > going to get back into the writing PC > software argument again if we do :D > > I think the 24/32 wire EDM printer might > win in a race with a vector one at the end > of the day anyways. > Hi Alan and Andrew, When I started playing with the idea of EDM ing PCBs a couple of years ago, my thought was to modify a printer and "print" the PCB using most of the PCL code built into the printer so that I could go directly from a jpeg or scan of magazine artwork to copper. Like many "good" ideas there were bumps on the road to realization!! Using vector graphics would be very much faster, especially if combined with multiple size selectable electrodes, but would lose the ability to scan artwork and then "print" it to the PCB. Also a vector approach requires attention to the ground return path. Andrew I believe Stefan did some experiments with burning the copper away as opposed to the spark erosion of EDM. I'm not sure as to his results, but perhaps he could help with your TIG experiments. I've pretty much suspended work on my PCB EDM project until I can figure out a reliable ( and cheap! ) way to get a pulse repetition rate of closer to 1 mHz. Since Volkan's inkjet announcement I'm pretty sure EDM ing PCBs is a thing of the past in any event. Curt Richards
2006-05-03 by roger lucas
Hi Curt,
Good to hear from you again.
>--- curt_rxr <cwrxr@...> wrote:
>
>Roger I used brass wire and distilled water and had
>arranged the servo
>circuit to feed the wire via a pinch roller and worm
>screw drive. the
>servo circuit is as per the NASA / Garden of EDM
>circuit.
I am in the middle of designing an electrode feed
system similar to yours. I have not heard of the NASA
circuit, is it some sort of servo drive?
>Roger the gap breakdown voltage controls the gap via
>the servo. As
>the electrode ( brass wire ) advances the gap closes
>until the spark
>after which the electrode retracts so the system is
>ready for he next
>spark.
If I understand this right you are initiating the
spark by advancing the electrode and retreating it at
each point. How does this keep up with your scanning
speed of approx 20 inches/sec? Or have I totally
misunderstood the operation of the servo?
My early experiments included a solenoid armature
oscillating an electrode at 50 Hz, amplitude about
1mm. This worked very well since the spark always
initiated at the dielectric breakdown point. However,
at the moment I can see no way of integrating the
electrode feed with the solenoid arrangement. If I
could it would answer a lot of problems.
>Hi Roger,
>
>I'm glad to see someone making progress. My system
>is stalled at a
>pulse repetition rate of 200,000 per second using
>IGBTs designed for
.auto igniton system. That rate gives me about an
>hour and a quarter
>processing time for an 8 inch by 12 inch PCB >using
.001 inch brass wire
>as an electrode. It makes a real nice board, but I
>can use Toner
>Transfer and CuCl2 bubble etching to make five boards
>in the same time!
>
>I'll be interested in your advances to the art, but
>right now it looks
>to me like the direct print inkjet system will
>replace TT and EDM for
>homebrew PCB prototyping.
>
>Curt Richards
My boards are all 4 x 3 inches, but the attraction of
EDM is it is the cheapest way to go, and it can be
left on its one to process with virtually no board
preparation, and no ink or etchant costs.
Roger
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NEW - Yahoo! 360 \ufffd Your one place to blog, create, publish and share! http://uk.360.yahoo.com2006-05-03 by roger lucas
--- Andrew <andrewm1973@...> wrote:
>No problems. BMP files are pretty easy to read.
>
>I will have a play around with them in the next few
>days.
Andrew,
Many thanks, will look forward to that.
>
>For my purposes - I will still need to compress them
>(G3 my pref) just to get them down to the plotter in
>under 4 hours.
>
>I don't quite understand the "motivate onesself
>after lunch" comment. Is this "lunch" you refer to
>something about 1/2 way through the day that we call
>"Rum o'clock" :D
What we call "Going for a swift half" I think.
R:
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24 FIFA World Cup tickets to be won with Yahoo! Mail http://uk.mail.yahoo.com2006-05-03 by Alan King
Andrew wrote: > >I think the 24/32 wire EDM printer might >win in a race with a vector one at the end >of the day anyways. > > > 24 things to fail at every step, better start now so it can work by 2012.. :) Alan
2006-05-03 by Herbert E. Plett
--- Russell Shaw <rjshaw@...> wrote: > > Multi-platform is easy as long as you exclude M$;) > I didn't pretend to be thaaat optimistic ... :) __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
2006-05-03 by Herbert E. Plett
--- Andrew <andrewm1973@...> wrote: ... > I think a fax program would have a fit > if you gave it a BMP that was 12000 x > 20000 dots. It is normally dealing > with files that are 204x204 DPI not > 2000x2000 dpi. just don't tell it it's 2000x2000, tell it it's 200x200 but 10x larger... not sure how :( __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
2006-05-03 by Herbert E. Plett
--- Russell Shaw <rjshaw@...> wrote: > Most "real" machines read G-code, that has been > generated from the original CAD data such as DXF > (gerber is G-codes). > > By converting all external data types to one format > suited to the machine, machine complexity is minimized. yes and no G-code is for managing vector movements, not raster patterns __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
2006-05-03 by Alan King
>My boards are all 4 x 3 inches, but the attraction of >EDM is it is the cheapest way to go, and it can be >left on its one to process with virtually no board >preparation, and no ink or etchant costs. > >Roger > > Inkjet is preeminiently reliable, with low costs and little extra work for etching. Far more likely to have to watch the EDM or have more often mechanical problems, plus wire and electricity isn't zero either, even expensive ink will work out very low cost per board when it's only used for PCB. All things considered it's unlikely to actually beat out the inkjet, and even if it did it'd be so marginal for the extra work of setting it up and keeping things running. Doing it for fun is one thing since it'll be very cool, but if you're expecting practicality I doubt it'll work out too well, just hard to see it coming out ahead by enough to make a difference. Alan
2006-05-03 by Stefan Trethan
I agree with you, inkjet may well turn out to be the most efficient overall. EDM would do away with the need for chemical etching. It would go that one step further towards making things easier, but it remains to be seen if the limits and problems do not far outweigh that advantage. Especially resolution and speed are things that i'm not at all confident will work out sufficiently. ST
On Wed, 03 May 2006 19:44:33 +0200, Alan King <alan@...> wrote: > Inkjet is preeminiently reliable, with low costs and little extra work > > for etching. Far more likely to have to watch the EDM or have more > > often mechanical problems, plus wire and electricity isn't zero either, > > even expensive ink will work out very low cost per board when it's only > > used for PCB. All things considered it's unlikely to actually beat out > > the inkjet, and even if it did it'd be so marginal for the extra work of > > setting it up and keeping things running. Doing it for fun is one thing > > since it'll be very cool, but if you're expecting practicality I doubt > > it'll work out too well, just hard to see it coming out ahead by enough > > to make a difference. > > > Alan
2006-05-03 by curt_rxr
Hi Roger, --- In Homebrew_PCBs@yahoogroups.com, roger lucas <ralucas4277@...> wrote: > > Hi Curt, > > Good to hear from you again. > > > I am in the middle of designing an electrode feed > system similar to yours. I have not heard of the NASA > circuit, is it some sort of servo drive? It's the circuit used in the Garden of EDM -- I'll be glad to e mail a PDF of the original NASA Tech brief to you if you like. > > If I understand this right you are initiating the > spark by advancing the electrode and retreating it at > each point. How does this keep up with your scanning > speed of approx 20 inches/sec? Or have I totally > misunderstood the operation of the servo? You've got it exactly right. It's not a problem -- the pinch roller that feeds the wire through the insulating sleeve is driven on the same principal as a voice coil drive in a hard drive and doesn't need to move the electrode very much at all. > > My early experiments included a solenoid armature > oscillating an electrode at 50 Hz, amplitude about > 1mm. This worked very well since the spark always > initiated at the dielectric breakdown point. However, > at the moment I can see no way of integrating the > electrode feed with the solenoid arrangement. If I > could it would answer a lot of problems. There are two ways to implement the servo. One is to use a stepper to control the pinch roller whichs feeds the brass wire through the guide the other is to use a worm drive and dc motor. Your vibrating electrode is the same approach Ben Flemming used in his Ramah Tap Burner design and should work well for PCBs which are *FLAT*. It would simplify the overall design a ton. Well Done!! > My boards are all 4 x 3 inches, but the attraction of > EDM is it is the cheapest way to go, and it can be > left on its one to process with virtually no board > preparation, and no ink or etchant costs. > > Roger Yep!! And if you incorperate a drill head on the back of your gantry you'll be able to drill the boards in water and save on dust collection. Roger, I'm not saying the PCB EDM is a dead end -- just my system is stonewalled! Since my major efforts in the spring and summer are working on various Willys Jeep and Truck restoration projects and I won't be much help in developing the PCB EDM until fall. Good Luck to you Roger and feel free to ask me questions, I'll try to be helpfull. Curt Richards
2006-05-03 by Andrew
> Curt wrote: > > Andrew I believe Stefan did some > experiments with burning the copper away > as opposed to the spark erosion of EDM. > I'm not sure as to his results, but > perhaps he could help with your TIG > experiments. Curt - is wasn't a serious experiment that I thought would lead somewhere - I just wanted to be destructive in a way that didn't involve goats :D
2006-05-03 by Andrew
> Roger wrote: > My boards are all 4 x 3 inches, but the attraction of > EDM is it is the cheapest way to go, and it can be > left on its one to process with virtually no board > preparation, and no ink or etchant costs. Who cares about "cheapest" I think "most automated" might be the winner. And if you include ink drying and curing time - I think it could win for speed as well.
2006-05-03 by Andrew
> >andrewm wrote: > > > >I think the 24/32 wire EDM printer might > >win in a race with a vector one at the end > >of the day anyways. > AlanK wrote: > 24 things to fail at every step, better > start now so it can work by 2012.. :) Them there fandangled ink jet printers have between 48 and 120 nozzels per colour and they don't break down more than 3 times a day :D
2006-05-03 by Andrew
>Alan wrote: > Doing it for fun is one thing since it'll > be very cool, but if you're expecting > practicality I doubt it'll work out too > well, just hard to see it coming out ahead > by enough to make a difference. I will never replace my beloved photo-process never-never I tell you - not over my dead body. However I think the EDM could/maybe/possibly be more attractive than the inkjet if the inkjet stuff is going to have to have all the "steps" Washing Drying Printing Curing Etching EDM would have one step. Like mechanical isolation milling does. Turn it on, go and have a rum, come back an hour later. EDM is meant to be an unattended process. Reliabilty isn't anything I am scared of with the idea either. I would trust a well designed system to keep running a long time. And if it does fail - it should know how to fail gracfully.
2006-05-03 by Stefan Trethan
On Wed, 03 May 2006 22:07:28 +0200, Andrew <andrewm1973@...> wrote: > Them there fandangled ink jet printers have > > between 48 and 120 nozzels per colour and > > they don't break down more than 3 times a > > day > Yea but they were built by some guy over at a garage shop called epson that builds a couple a day, and so he might have had a chance to work out the problems. If i was building a EDM with many electrodes it would be my first, so i think it would be best to start with one electrode instead and actually get it to work. ST
2006-05-03 by Stefan Trethan
On Wed, 03 May 2006 22:16:23 +0200, Andrew <andrewm1973@...> wrote: > > > EDM would have one step. Like mechanical > > isolation milling does. Turn it on, go and > > have a rum, come back an hour later. > > > EDM is meant to be an unattended process. Do you actually do mechanical milling? I don't, but as far as i am aware of it is far from trouble free and working well unattended. You get other stuff with EDM, like changing the water, caring and feeding of electrodes, ... stuff... ST
2006-05-03 by Codesuidae
Stefan Trethan wrote: > On Wed, 03 May 2006 22:16:23 +0200, Andrew <andrewm1973@...> wrote: > >> EDM would have one step. Like mechanical >> isolation milling does. Turn it on, go and >> have a rum, come back an hour later. >> EDM is meant to be an unattended process. >> > > Do you actually do mechanical milling? > I don't, but as far as i am aware of it is far from trouble free and > working well unattended. > I do. If you have some practice getting your setup right it's pretty well unattended, presuming your equipment is reliable. If the equipment isn't suitable to the task or tends to fail you can waste a lot of time and materials whether you are watching it or not. Dave K
2006-05-03 by Andrew
> ST wrote > Do you actually do mechanical milling? > I don't, but as far as i am aware of it is > far from trouble free and working well > unattended. No - I don't do mechanincal milling. I have compared the results of it and the time it takes to photo. I stuck to photo. I have seen a few people that could not get photo to work well and thought "There has to be a better way" and have tried milling. Some milling shops get it to work relaibly some don't. I would guess the ones that don't are probably still looking for that better way The ones that do get it to work probably care for thier machines and know its limits. > You get other stuff with EDM, like > changing the water, caring and feeding > of electrodes, ... stuff... Hopefully the "stuff" is just once a month maintenace like our CuCl etchant. It needs looking after (acid/air/water) but not every single board. Maybe the EDM will need changing a roll of wire once a year and replaceing water/filters once a month. Who knows till its been running a year :D
2006-05-03 by Andrew
> ST wrote: > Yea but they were built by some guy > over at a garage shop called epson > that builds a couple a day, and so > he might have had a chance to work > out the problems. I'm pretty sure from my dealing with epson inkjets those guys are _realy_ yet to sort out the problems :D Canon on the other hand - they might almost be reliable with inkjet. However in terms of reliabilty. Ink jet is a LONG way down the food chain from laser. And laser is a long way down the food chain from impact dot matrix with a tractor feed (if you consider the print head a consumable) > If i was building a EDM with many > electrodes it would be my first, > so i think it would be best to > start with one electrode instead > and actually get it to work. Yep - First class plan. I always learn to walk before I can run. But *IF* one electrode gave good results. Then two electrodes would be faster. And *IF* two electrodes worked - then 32 might be a goal. I am not saying I am competant enough to pull it off. I sometimes have a hard time pouring drinks into LARGE glasses. It would be a miracle if I could make something that was 0.01mm wide and realiable. :D
2006-05-03 by Alan King
Andrew wrote: > >>AlanK wrote: >> 24 things to fail at every step, better >>start now so it can work by 2012.. :) >> >> > >Them there fandangled ink jet printers have >between 48 and 120 nozzels per colour and >they don't break down more than 3 times a >day :D > > > Which inkjet also has 24+ independent complex mechanical systems that have to be maintained? It's a relative PITA to keep 2 or 3 of something like that working well. Heck took them 15 or 20 years to get inkjets even close to right, and even now much of the rightness is simply waste half the ink cleaning the nozzles.. They're reliable because they're simple and fluid instead of mechanical all around.. Make you a deal, get just 6 working well for a week then you can tell me how it is so much better than an inkjet.. :) Again, I'll expect to hear back about it by at least 2012.. Even the 2 or 3 feeds I mentioned is problematic, but the advantage would outweigh the extra complexity and problems of 2 or 3. But the DISC does have the strong advantage of much more edge area for a far lower erosion distance. It might last long enough with a decent multiple to not need feeding over the making of a board. A stack of copper washers on a tube, insulated and with their own supply, just scan back and forth, when the washers have scanned to the next washer's area just move the whole assembly. Spinning at least some to constantly expose fresh edge and get power to each washer through the tube. I can see something like that working far more easily than getting 24 seperate wire feeds to cooperate for any real period of time.. Alan
2006-05-03 by Alan King
Codesuidae wrote: > " > > presuming your equipment is reliable. If the equipment >isn't suitable to the task or tends to fail you can waste a lot of time >and materials whether you are watching it or not." > > Um, isn't that part true of absolutely everything? Getting 24 wire feeds to the point of not having hiccups will take a buttload of over engineering, Jlo would be envious. And it will likely still require an exploding goat here or there too..
2006-05-03 by Andrew
> AK wrote: > Which inkjet also has 24+ independent complex > mechanical systems that have to be maintained? They have 48 complex mechanincal systems. Piezo electric effects are mechanical. And their main problem is you can't maintain them easily - you just throw them away. (which isn't so bad 'cause they are a mass consumer item that costs 80 cents to make the whole cartridge) I shall refer you to the 15 page long thread on amonia/ajax/pumping/syringing to attempt to maintain ink jets to back up that point The complexity of the EDM head would not be TOO much more than an impact dot matrix. EDM has no contact and no force on the tool head like milling. It is not subject to great force like an impact dot matrix even. A spool, a clamp, a voice coil. dirt would probably be your biggest enemy. > It's a relative PITA to keep 2 or 3 of > something like that working well. Heck took > them 15 or 20 years to get inkjets even close > to right, and even now much of the rightness > is simply waste half the ink cleaning the > nozzles.. They're reliable because they're > simple and fluid instead of mechanical all > around.. They also HAVE to be reliable. They have to be open-loop reliable. An ink jet printer does not know if a nozzel is working or not. There is a difference between individual component reliability, over all system reliability and perceived reliabilty (when a system is not smart enough to cope with small failures and fail gracefully) The EDM heads can have closed loop feedback and tell when they are/have failed. If it knows a head has failed the system could accomodate for that failure (and maybe run at a lower speed) I have some good books about reliability I can lend you if you like. > Make you a deal, get just 6 working well > for a week then you can tell me how it is > so much better than an inkjet.. :) Again, > I'll expect to hear back about it by at > least 2012.. I don't think I ever said I wanted to make one myself :S But if you want to make a valid challenge - BET me a bottle of bundy I CAN'T do it by 2012. Much more convincing that a glib "at least 2012" saying touchè under your breath and thinking you've made a point. > AK also wrote: > Getting 24 wire feeds to the point of not > having hiccups will take a buttload of over > engineering Refer to failing gracefully comment above. > And it will likely still require an > exploding goat here or there too.. We can only hope and pray :D (preps the goats and shivers in anticipation)
2006-05-04 by William Carr
On May 3, 2006, at 4:27 PM, Stefan Trethan wrote: > Do you actually do mechanical milling? > I don't, but as far as i am aware of it is far from trouble free and > working well unattended. I have a CNC machine, and the idea of leaving it unattended .... no.
2006-05-04 by cristian
> >Do you actually do mechanical milling? >I don't, but as far as i am aware of it is far from trouble free and >working well unattended. I do, UNATTENDED, with positive results every time. Cristian
2006-05-04 by Andrew
> BillC wrote: > I have a CNC machine, and the idea of > leaving it unattended .... no. > Is that a CNC milling machine for cutting big hunks of metal - or one for cutting little bits of GRP and copper ? I would not leave a CNC milling machine unattended. However the companies that sell some of the PCB mills list that as one of the points about having them.
2006-05-04 by roger lucas
Hi Curt,
Thanks for the info, just a couple of points
--- curt_rxr <cwrxr@...> wrote:
>It's the circuit used in the Garden of EDM -- I'll be
>glad to e mail a
>PDF of the original NASA Tech brief to you if you
>like.
If it is just the Garden of EDM, don't bother to send
at the moment, I have used bits of that but modded to
IPS etc.
>> My early experiments included a solenoid armature
>> oscillating an electrode at 50 Hz, amplitude about
>> 1mm. This worked very well since the spark always
>> initiated at the dielectric breakdown point.
>>However,
>> at the moment I can see no way of integrating the
>> electrode feed with the solenoid arrangement. If I
>> could it would answer a lot of problems.
>There are two ways to implement the servo. One is to
>use a stepper to
>control the pinch roller whichs feeds the brass wire
>through the guide
>the other is to use a worm drive and dc motor.
>Your vibrating electrode is the same approach Ben
>Flemming used in his
>Ramah Tap Burner design and should work well for PCBs
>which are
>*FLAT*. It would simplify the overall design a ton.
>Well Done!!
*BINGO* I have just found an ultra simple way of
integrating the electrode pinch feed with the
vibrating electrode, (without vibrating the pinch feed
mechanism). I will proto this w/e, and if it works,
I'll post a sketch.
BTW, do you have any info on the approx. erosion rate
of your 0.001 electrode. Does your electrode feed run
slowly or relatively fast? Just asking so I can
determine whether to use stepper or dc servo drive
motor.
>Yep!! And if you incorperate a drill head on the
>back of your gantry
>you'll be able to drill the boards in water and save
>on dust collection.
Yes, I intend to. why reload twice.
If this vibrating electrode approach is succesful,
there is no reason why 2 (or more) electrode modules,
(spaced on the X or Y axis), could not be driven
simultaneously to produce two boards of the same
design.
For those interested, the vibrating electrode is
driven by the solenoid arrangement in an aquarium
aeration pump. Simple, cheap and very effective.
However, production item may have to be a lighter
design to increase the oscillation frequency.
Curt, many thanks for your help
Roger
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Send instant messages to your online friends http://uk.messenger.yahoo.com2006-05-04 by Codesuidae
roger lucas wrote: > For those interested, the vibrating electrode is > driven by the solenoid arrangement in an aquarium > aeration pump. Simple, cheap and very effective. > However, production item may have to be a lighter > design to increase the oscillation frequency. Isn't the frequency of an aquarium pump determined by the power line frequency? In the designs I've seen its just a coil driven from the power line pushing a magnet connected to a lever that moves a diaphragm attached to a cavity with holes covered by small rubber flap valves. Dave K
2006-05-04 by roger lucas
>--- Codesuidae <codesuidae@...> wrote:
>
>roger lucas wrote:
>> For those interested, the vibrating electrode is
>> driven by the solenoid arrangement in an aquarium
>> aeration pump. Simple, cheap and very effective.
>> However, production item may have to be a lighter
>> design to increase the oscillation frequency.
>Isn't the frequency of an aquarium pump determined by
>the power line
>frequency? In the designs I've seen its just a coil
>driven from the
>power line pushing a magnet connected to a lever that
>moves a diaphragm
>attached to a cavity with holes covered by small
>rubber flap valves.
>
>Dave K
Yes it is, if you connect it to the mains. However
there is nothing to stop you driving it with a
variable frequency oscillator and a high voltage audio
power module, or just a mosfet and dc. Change the
magnet to a rare earth specimen and it fairly takes
off.
The rubber diaphragm has good damping. Result =
Variable Frequency electrode for less than \ufffd10.
Connect the the EDM PIC control and you can sync the
spark discharge to the 3 axis movement.
Roger
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To help you stay safe and secure online, we've developed the all new Yahoo! Security Centre. http://uk.security.yahoo.com2006-05-04 by William Carr
On May 4, 2006, at 12:37 AM, Andrew wrote: > Is that a CNC milling machine for > cutting big hunks of metal - or one for > cutting little bits of GRP and copper ? It's a CNC machine for making signage, cutting signfoam, wood, even brass if you use the lubricant spray. I don't have an engraver head so I don't think I'll try doing PCB work with it.
2006-06-24 by roel_cnc
--- In Homebrew_PCBs@yahoogroups.com, "roel_cnc" <atmelletje@...> wrote: > > i like the idea of making me own laserplotter. > > tested: a pointerlaser (some cheap thing) with an extra focus lense, a > red sensible film gave me super fine lines (close to a single cloth > fiber). > > did any of us fouling around with this idea !! > > tips and suggestions always welcome:) > > gr Roel (holland) > Hi all, M i started this toppic - got lots of replys on it with ideas :) i gonna use Cunningfellow's pll thing some stepper for the laser and a dma-16 card - high speed dio card up to 250kB/s some code compiled (TPascal)that eats the the 274 (gerber) files and output to the drum gr Roel
2006-06-25 by Andrew
>> Roel CNC wrote: >> >> i like the idea of making me own laserplotter. >> tested: a pointerlaser (some cheap thing) >> with an extra focus lense, a red sensible >> film gave me super fine lines (close to a >> single cloth fiber). >> >> did any of us fouling around with this idea !! >> >> tips and suggestions always welcome:) >> > Roel also wrote: > Hi all, > M i started this toppic - got lots of replys > on it with ideas :) > > i gonna use Cunningfellow's pll thing some > stepper for the laser and a dma-16 card - > high speed dio card up to 250kB/s some code > compiled (TPascal)that eats the the 274 (gerber) > files and output to the drum Roel - I have done a bit more work on the PLL thing. That one posted so far was just a test of concept / prototype. There are a few things un-needed and a few other things that are needed. It was built to do some tinkering with a commercial DC servo motor I had lying around. I finally want to just use a DC brushed motor with some optos ripped out of mice (to make it easier for others to get parts to build) Also - I was planning on getting the data out of a USB port (via an FT232) instead of some custom hardware in the PC (again ease to duplicate). The FT232 can do 4 Mb (which is same ballpark to 250 KB). However if you compress the 1000dpi data even with a simple algo like G3 fax you can fit the data stream down 100 kilo baud (assuming 1000dpi and 10" x 10" board in 10 minutes) I have sourced some toothed belts and linear shafts for moving the laser head. I have also found a source of cheapish lasers that can be focused down to small enough dot size if I can't find a simple repeatable solution for people to do the same with a cheap laser pointer. Very interested in your thoughts on the carraige part. You seem to have a lot more experience than I with CNC things (and PVC etch tanks). Do you think at 1000 (or 2000) DPI that there will be a sticktion problem? Do you think the tooth belt idea is going to be good enough or do you think that I might need to use a very fine pitch leadscrew? I have done some software on the PC to read a BMP file compress it and send it out to my hardware. I was just going to use and external gerber to BMP thing. However - I have no objections to reading geber directly if you would like to work together on the project. The only other though I had from the PC side was to maybe write a GDI driver. That might be a bit out of my league though. andrewm (or cunningfellow to some)
2006-06-26 by Andrew
>>>>> Roel CNC wrote: >>>>> <snip - "laser plotter anyone"> >>>> andrewm wrote: >>>> <snip - "not a bad idea"> >>> lots of other people wrote: >>> <snip - "how about doing it this way"> >> Roel wrote again: >> <snip - "why the hell not"> > andrewm wrote again: > <snip - other thoughts> > The only other though I had from the PC side > was to maybe write a GDI driver. That might be > a bit out of my league though. Have now investigated writing a printer driver for windows. There is a thing called unidrv that is quite easy to do. You don't even realy need to do any programming at all for simple cases. I am going to write/make one of these and make my laser plotter pretend to be a printer. It makes it a bit windows bound - but I guess thats the world we live in. Only problems left now are the carraige and the laser.
2006-06-26 by roel_cnc
--- In Homebrew_PCBs@yahoogroups.com, "Andrew" <andrewm1973@...> wrote: > > >> Roel CNC wrote: > >> > >> i like the idea of making me own laserplotter. > >> tested: a pointerlaser (some cheap thing) > >> with an extra focus lense, a red sensible > >> film gave me super fine lines (close to a > >> single cloth fiber). > >> > >> did any of us fouling around with this idea !! > >> > >> tips and suggestions always welcome:) > >> > > > Roel also wrote: > > Hi all, > > M i started this toppic - got lots of replys > > on it with ideas :) > > > > i gonna use Cunningfellow's pll thing some > > stepper for the laser and a dma-16 card - > > high speed dio card up to 250kB/s some code > > compiled (TPascal)that eats the the 274 (gerber) > > files and output to the drum > > Roel - I have done a bit more work on the PLL > thing. That one posted so far was just a test of > concept / prototype. There are a few things > un-needed and a few other things that are needed. > lots of schematics on the net for pll that can be used i think > It was built to do some tinkering with a > commercial DC servo motor I had lying around. > I finally want to just use a DC brushed motor > with some optos ripped out of mice (to make it > easier for others to get parts to build) > > Also - I was planning on getting the data out of > a USB port (via an FT232) instead of some custom > hardware in the PC (again ease to duplicate). > > The FT232 can do 4 Mb (which is same ballpark to > 250 KB). However if you compress the 1000dpi > data even with a simple algo like G3 fax you can > fit the data stream down 100 kilo baud (assuming > 1000dpi and 10" x 10" board in 10 minutes) > > I have sourced some toothed belts and linear > shafts for moving the laser head. I have also > found a source of cheapish lasers that can be > focused down to small enough dot size if I can't > find a simple repeatable solution for people to > do the same with a cheap laser pointer. i was thinking to use a ldiode from a dvd burner they can trow up to 70mw and with a good lense a super ultra thin line > > Very interested in your thoughts on the carraige > part. You seem to have a lot more experience > than I with CNC things (and PVC etch tanks). > Do you think at 1000 (or 2000) DPI that there will > be a sticktion problem? Do you think the tooth > belt idea is going to be good enough or do you > think that I might need to use a very fine pitch > leadscrew? a lead screw for this job will be expensive i think first touhts was to use a beld but after some thinking a steel wire is super stiff and easy to gear > > I have done some software on the PC to read a > BMP file compress it and send it out to my > hardware. I was just going to use and external > gerber to BMP thing. However - I have no > objections to reading geber directly if you would > like to work together on the project. > > The only other though I had from the PC side > was to maybe write a GDI driver. That might be > a bit out of my league though. > > andrewm (or cunningfellow to some) > email me if you like Andrew or maybe msn its faster hey' gr Roel
2006-06-27 by Andrew
> Roel wreto: > lots of schematics on the net for pll that > can be used i think Yep - I think the only thing there is more schematics of on the net is propeller clocks. > i was thinking to use a ldiode from a dvd > burner they can trow up to 70mw and with a > good lense a super ultra thin line OK - They already have focus optics which is good. But what colour are they ? I thought they where shorter than 630nm. 1mW is pleanty for the comercial film if you find a diode that doesnt do 70mW :D > a lead screw for this job will be expensive Fine pitch brass bolt was my thought. Not a hardend and ground zero backlas ballnut :D > i think first touhts was to use a beld but > after some thinking a steel wire is super > stiff and easy to gear I used some stainless steel rope (from model plain control wires) for something in the past. The multi-stranded-ness of it made it easy to use. It might be an idea again. > email me if you like Andrew or maybe msn > its faster hey' Yeah - MSN works for me. andrewm1973 at hot-whatever
2006-06-29 by loco_labs
Hi, im building a small CNC type machine using steppers and belts to move a dremel in 3 axis, controlled from parallel port. I will use eagle pcb and then create a gcode file for mach3 to route the isolation. for moving a laser diode around you will not need any torque at all, so it would be possible to get away with using a few small stepper motors from printers or using the assembly from flatbed scanners to perform x and y movement. but it will be very slow. if you google up 'orbit picstep' you will find a very nice stepper driver that has step, direction & enable signals. I know of UV sensitive boards, where can i get the red sensitive ones as mentioned before? -Michael --- In Homebrew_PCBs@yahoogroups.com, "roel_cnc" <atmelletje@...> wrote:
> > --- In Homebrew_PCBs@yahoogroups.com, "Andrew" <andrewm1973@> > wrote: > > > > >> Roel CNC wrote: > > >> > > >> i like the idea of making me own laserplotter. > > >> tested: a pointerlaser (some cheap thing) > > >> with an extra focus lense, a red sensible > > >> film gave me super fine lines (close to a > > >> single cloth fiber). > > >> > > >> did any of us fouling around with this idea !! > > >> > > >> tips and suggestions always welcome:) > > >> > > > > > Roel also wrote: > > > Hi all, > > > M i started this toppic - got lots of replys > > > on it with ideas :) > > > > > > i gonna use Cunningfellow's pll thing some > > > stepper for the laser and a dma-16 card - > > > high speed dio card up to 250kB/s some code > > > compiled (TPascal)that eats the the 274 (gerber) > > > files and output to the drum > > > > Roel - I have done a bit more work on the PLL > > thing. That one posted so far was just a test of > > concept / prototype. There are a few things > > un-needed and a few other things that are needed. > > > lots of schematics on the net for pll that can be used i think > > > It was built to do some tinkering with a > > commercial DC servo motor I had lying around. > > I finally want to just use a DC brushed motor > > with some optos ripped out of mice (to make it > > easier for others to get parts to build) > > > > Also - I was planning on getting the data out of > > a USB port (via an FT232) instead of some custom > > hardware in the PC (again ease to duplicate). > > > > The FT232 can do 4 Mb (which is same ballpark to > > 250 KB). However if you compress the 1000dpi > > data even with a simple algo like G3 fax you can > > fit the data stream down 100 kilo baud (assuming > > 1000dpi and 10" x 10" board in 10 minutes) > > > > I have sourced some toothed belts and linear > > shafts for moving the laser head. I have also > > found a source of cheapish lasers that can be > > focused down to small enough dot size if I can't > > find a simple repeatable solution for people to > > do the same with a cheap laser pointer. > > i was thinking to use a ldiode from a dvd burner they > can trow up to 70mw and with a good lense a super ultra thin line > > > > Very interested in your thoughts on the carraige > > part. You seem to have a lot more experience > > than I with CNC things (and PVC etch tanks). > > > Do you think at 1000 (or 2000) DPI that there will > > be a sticktion problem? Do you think the tooth > > belt idea is going to be good enough or do you > > think that I might need to use a very fine pitch > > leadscrew? > > a lead screw for this job will be expensive i think > first touhts was to use a beld but after some thinking > a steel wire is super stiff and easy to gear > > > > I have done some software on the PC to read a > > BMP file compress it and send it out to my > > hardware. I was just going to use and external > > gerber to BMP thing. However - I have no > > objections to reading geber directly if you would > > like to work together on the project. > > > > > The only other though I had from the PC side > > was to maybe write a GDI driver. That might be > > a bit out of my league though. > > > > andrewm (or cunningfellow to some) > > > email me if you like Andrew or maybe msn its faster hey' > > gr Roel >
2006-06-29 by Andrew
>> Roel, Andrew and others wrote: >> <Stuff about a drum plotter> > Loco labs wrote: > > im building a small CNC type machine using > steppers and belts to move a dremel in 3 > axis, controlled from parallel port. I will > use eagle pcb and then create a gcode file > for mach3 to route the isolation. Have you tried the dremel tool to mill fiberglass PCB ? I beleive the speed (20K rpm or so) is a bit slow and that they also have a bit much run out to do a nice job of it. The comercial machines you quite fast (60K) low run out spindles. Post pics when your dont though. We like to see this kinda stuff being done. > for moving a laser diode around you will > not need any torque at all, so it would be > possible to get away with using a few > small stepper motors from printers or > using the assembly from flatbed scanners > to perform x and y movement. but it will > be very slow. We only need a Y axis for the stepper motor. X axis is around the drum as it spins. Yes stepper will only need to be very small as all it needs to move is the carraige for the laser. There is one thing I have no idea about and no one else seems to have posted any thoughts. Am I going to have a problem with sticktion. Sticking-Friction which is the friction that is higher while something is at rest. You can have a problem that you tell the stepper to move one tiny step. The head sticks and does not move. You tell it to do another step. It is still stuck. You keep giving it steps then all of a studden it will jump X steps fwd and stick again. You can get over sticktion by moving the carraige back and FWD each time - but that slows things down a bit. 15 minutes for a print is a bit slow - but not too bad if the quality is good. > if you google up 'orbit > picstep' you will find a very nice stepper > driver that has step, direction & enable > signals. Driving one stepper is pretty trivial so I shall just do it out the main boards AVR (saves people looking at me funny for using a pic as well) > I know of UV sensitive boards, where can > i get the red sensitive ones as mentioned > before? No red sensitive boards - only film. Use red laser to print on to film. Develop film. Use developed film to expose board with UV. BTW - welcome to the group - where in OZ are you (just in case I need to rib you if QLD manages another 30-6 next wed night)
2006-06-30 by loco_labs
Hi, My name is Michael and im from Melbourne. > Have you tried the dremel tool to mill > fiberglass PCB ? I have tried engraving with a 60degree bit into the fibreglass board by hand and if going from the edge its likle butter, but it takes some force to pierce the copper because the bit wasnt intended for drilling. Im hoping the dremel will be good enough for basic smd. as for the sticktion, one idea i had was; you see where on the older carriages of printers/scanners they had bronze guides that slide around a steel rod, what if there were a few holes drilled into the bronze around the diameter and a small pump would supply some oil/air under pressure into the holes. then the fluid should slowly leak out around the rod and hopefully it floats on a pillow of oil. or even pressurised air. I have seen some precision grinders that used air compressor for frictionless bearing. problem is its easier said than done. And when i get some time ill sort out my progress and put it on the internet for all to see. -cheers
2006-07-02 by Andrew
>"loco_labs" wrote: > <snip> > as for the sticktion, one idea i had was; you > see where on the older carriages of printers/ > scanners they had bronze guides that slide > around a steel rod, what if there were a few > holes drilled into the bronze around the > diameter and a small pump would supply some > oil/air under pressure into the holes. then > the fluid should slowly leak out around the > rod and hopefully it floats on a pillow of > oil. or even pressurised air. > <snip> I was considering air bearings for a little while (the big 50 thousand dollar plotters use them) But decided it sounds like a lot of trouble unless I find out a simpler solution won't work.
2006-07-17 by David Cureton
Did i miss something? Are there any links to photos of the results. Thanks, David roger lucas wrote:
> Well, I finally motivated myself this holiday weekend > to get my PCB EDM lash-up to cut copper, and, YES, it > does cut clean lines thru the copper without board > burning or marking. Shine a torch through the tracks > from the rear of the board and there is a faithful > line of light, (no firstborn goats or pentagrams > neccessary). > > With my highest power lens and head magnifier I could > see no trace of copper whiskers on the EDM'd track. > Interestingly, the copper is blasted away entirely > below the cross section of the wire, there is no > 'erosion bleeding' into the surrounding copper outside > of the wire dia. > > Have only cut straight lines so far with 26 swg and > with a 0.2 mm step increment, (need to modify the > stepper gear ratio), and with multiple (continuous) > sparking between increments, (no on/off sparks or > raster yet). > > One significant problem has emerged which Curt > Richards did not address, (or if he did, he did not > mention it). The wire electrode erosion is > significant, and will require an active Z axis > correction to maintain as consistent a spark gap > distance as possible between the electrode and pcb > surface. To do this I will insert a routine to 'touch > down' the electrode on the copper to zero the gap,(no > spark, closure sensed by two PIC output/inputs for > voltage present), and then retreat the electrode to a > standard clearance before any track eroding is > commenced, (Andrew, this is why I need the BMP byte by > byte transfer). This will also tend to compensate for > any board distortion. > > Used tapwater as a dielectric with no problems, (the > modified Garden of EDM circuit controls the > electrolysis with no problems). > > Curt controlled his spark discharge voltage by > dynamically adjusting the electrode gap on the fly. I > think that for pcb work this is not the correct > approach because of the wire erosion problem, since > one needs to KNOW the gap distance AND available > discharge energy BEFORE discharge, which is why I am > going for the touch down zeroing method, (slower but > speed is not significant at the moment). The discharge > energy will be set by presetting the voltage level > required and capacitor selection, (simple comparator > control integrated into the spark control). I think > this is the secret of successful pcb edm'ing. > > This is really looking as if direct raw copper board > to finished pcb is going to be possible. > > Roger > > > > > ___________________________________________________________ > Yahoo! Photos \ufffd NEW, now offering a quality print service from just 7p a photo http://uk.photos.yahoo.com > > > Be sure to visit the group home and check for new Links, Files, and Photos: > http://groups.yahoo.com/group/Homebrew_PCBs > > If Files or Photos are running short of space, post them here: > http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ > Yahoo! Groups Links > > > > > > > > > ** ACCEPT: CRM114 PASS Markovian Matcher ** > CLASSIFY succeeds; success probability: 1.0000 pR: 69.2692 > Best match to file #0 (nonspam.css) prob: 1.0000 pR: 69.2692 > Total features in input file: 5621 > #0 (nonspam.css): features: 1574864, hits: 168951, prob: 1.00e+00, pR: 69.27 > #1 (spam.css): features: 700736, hits: 79657, prob: 5.38e-70, pR: -69.27 > > -=-Extra Stuff-=- > > From sentto-4505361-14046-1146586123-yahoo=dcureton.com@... Wed May 03 02:09:25 2006 > Return-path: <sentto-4505361-14046-1146586123-yahoo=dcureton.com@...> > Envelope-to: yahoo@... > Delivery-date: Wed, 03 May 2006 02:09:25 +1000 > Received: from n16a.bullet.scd.yahoo.com ([66.94.237.45]) > by whitetail with smtp (Exim 4.50) > id 1FaxRE-0001NB-O5 > for yahoo@...; Wed, 03 May 2006 02:09:25 +1000 > Comment: DomainKeys? See http://antispam.yahoo.com/domainkeys > DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=lima; d=yahoogroups.com; > b=Deo1r8Ca+ejr1GQGHFZDSS1S34fOlWbQd4wm9Xos6yJIVm6p8WvXAr2mUZ/RhXmB/a6A/tbLoiQ9VXVaM3t1vHq1Sk+YyfALAKxRt/ePyVI0NAzh37/VGKyftBT/PKTH; > Received: from [66.218.69.5] by n16.bullet.scd.yahoo.com with NNFMP; 02 May 2006 16:08:52 -0000 > Received: from [66.218.66.36] by t5.bullet.scd.yahoo.com with NNFMP; 02 May 2006 16:08:52 -0000 > X-Yahoo-Newman-Property: groups-email > X-Yahoo-Newman-Id: 4505361-m14046 > X-Sender: ralucas4277@... > X-Apparently-To: Homebrew_PCBs@yahoogroups.com > Received: (qmail 5150 invoked from network); 2 May 2006 16:08:23 -0000 > Received: from unknown (66.218.66.166) > by m30.grp.scd.yahoo.com with QMQP; 2 May 2006 16:08:23 -0000 > Received: from unknown (HELO web25911.mail.ukl.yahoo.com) (217.146.176.249) > by mta5.grp.scd.yahoo.com with SMTP; 2 May 2006 16:08:22 -0000 > Received: (qmail 56193 invoked by uid 60001); 2 May 2006 16:07:20 -0000 > Message-ID: <20060502160720.56191.qmail@...> > Received: from [195.93.21.34] by web25911.mail.ukl.yahoo.com via HTTP; Tue, 02 May 2006 17:07:19 BST > To: Homebrew_PCBs@yahoogroups.com > In-Reply-To: <20060502150532.7175.qmail@...> > > X-eGroups-Msg-Info: 1:0:0:0 > From: roger lucas <ralucas4277@...> > X-Yahoo-Profile: ralucas4277 > Sender: Homebrew_PCBs@yahoogroups.com > MIME-Version: 1.0 > Mailing-List: list Homebrew_PCBs@yahoogroups.com; contact Homebrew_PCBs-owner@yahoogroups.com > Delivered-To: mailing list Homebrew_PCBs@yahoogroups.com > List-Id: <Homebrew_PCBs.yahoogroups.com> > Precedence: bulk > List-Unsubscribe: <mailto:Homebrew_PCBs-unsubscribe@yahoogroups.com> > Date: Tue, 2 May 2006 17:07:19 +0100 (BST) > Subject: [Homebrew_PCBs] PCB EDM MILL Initial Tests > Reply-To: Homebrew_PCBs@yahoogroups.com > Content-Type: text/plain; charset=ISO-8859-1 > Content-Transfer-Encoding: 8bit > > > Well, I finally motivated myself this holiday weekend > to get my PCB EDM lash-up to cut copper, and, YES, it > does cut clean lines thru the copper without board > burning or marking. Shine a torch through the tracks > from the rear of the board and there is a faithful > line of light, (no firstborn goats or pentagrams > neccessary). > > With my highest power lens and head magnifier I could > see no trace of copper whiskers on the EDM'd track. > Interestingly, the copper is blasted away entirely > below the cross section of the wire, there is no > 'erosion bleeding' into the surrounding copper outside > of the wire dia. > > Have only cut straight lines so far with 26 swg and > with a 0.2 mm step increment, (need to modify the > stepper gear ratio), and with multiple (continuous) > sparking between increments, (no on/off sparks or > raster yet). > > One significant problem has emerged which Curt > Richards did not address, (or if he did, he did not > mention it). The wire electrode erosion is > significant, and will require an active Z axis > correction to maintain as consistent a spark gap > distance as possible between the electrode and pcb > surface. To do this I will insert a routine to 'touch > down' the electrode on the copper to zero the gap,(no > spark, closure sensed by two PIC output/inputs for > voltage present), and then retreat the electrode to a > standard clearance before any track eroding is > commenced, (Andrew, this is why I need the BMP byte by > byte transfer). This will also tend to compensate for > any board distortion. > > Used tapwater as a dielectric with no problems, (the > modified Garden of EDM circuit controls the > electrolysis with no problems). > > Curt controlled his spark discharge voltage by > dynamic > > > -0-0-0- >
2006-07-17 by Cristian
> . I think > > this is the secret of successful pcb edm'ing. > > > > This is really looking as if direct raw copper board > > to finished pcb is going to be possible. > > > > Roger Roger, it works, for sure at the beginning, when there are enough copper to create the opposite polarity/electrode, but how you manage to fire the last sparks, when there are no more connection to the opposite polarity/electrode? Are you advancing line by line in horizontal lines? Could you explain your bmp to Machine software? Cristian
2006-09-09 by Andrew
An update for anyone interested. First posted in June or there abouts my intent to make a photoplotter along the lines of the one John Elson did. Said at the time I would probably take about six months to get it done. Well - I am about 1/2 way along my time line and in light of other comments around I thought I should give everyone an update. From the outset the plan has been to make the whole thing with simple technology and to do an RTFM build document on it so anyone else can make one. So far I have built a board that has all that was needed to control a servo motor and create a pixel clock. (the prototype shown in the files section). Along with this the CPU that created the pixel stream (not shown in files section yet) has been built. Next step/goal was to get it all comunicating with the computer. Originaly was going to make it terminal driven and to x-modem the plotter a TIFF file. The hope here was to make it platform independant. This turned out to be a stupid idea. The TIFF standard does not guarantee linear files :( After giving up that idea someone pointed me in the direction of windows Miniport drivers. They are very simple to make and I now have the electonics of the photoplotter pretending to be a normal laser printer to any windows machine. if anyone ever needs to do anything similar I recomend that path. Tasks still to complete are 1, Laser driving circuit 2, Mechanics of the drum 3, Mechaincs of the carraige I hope to have these finished some time soon. NB soon is a relative term - I published some of my first RTFM builds well over 10 years ago when I was still a teenager. If you go and look at them on the wayback machine I still am promising to do the NTSC version of one of those projects "soon" :D