Homebrew PCBs

Hi guys!

I''ve seen this: http://c4r0.skrzynka.org/_hv/index.php?page=lasers/cnc2

I was thinking: why don't use this kind of laser to burn the
photoresist board. After you develop it and ready for the etch. I
knoww the CO2 laser but it's more expensive than a simple burn laser
from a DVD burner.

Any idea? 

Bye!

Juan EA7FNJ wrote:
> Hi guys!
> I''ve seen this: http://c4r0.skrzynka.org/_hv/index.php?page=lasers/cnc2
> 
> I was thinking: why don't use this kind of laser to burn the
> photoresist board. After you develop it and ready for the etch. I
> knoww the CO2 laser but it's more expensive than a simple burn laser
> from a DVD burner.

A laser from a DVD burner should be quite adequate to expose photoresist.

I played around with large argon lasers and scanners as a means of resist 
exposure rather a long time ago.

It was difficult to keep things square, the right size and in focus but the 
results were still rather acceptable.

A x-y plotter rig like those used with CO2 laser engravers would be a much 
better option and a great deal cheaper.

You'd probably want to use a considerably longer focal length lense.

X-Y CO2 laser engravers usually have the collimated laser statically mounted 
and shining along one axis hitting a travelling 45 degree mirror which 
redirects the beam up the other axis to another travelling 45 degree mirror 
which in turn directs the beam down onto the work through a focusing optic.


DVD laser diodes are probably best mounted on the gantry aimed directly at the 
work.

Thanks for the answer.

Well, a CO2 laser can engrave the copper directly (I think). But It's
so much more expensive than a DVD-RW laser.

How does a CO2 laser tube cost? I saw How it works and it' so impresive.
 

--- In Homebrew_PCBs@yahoogroups.com, Mark Robinson
<mark.robinson@...> wrote:
> 
> A laser from a DVD burner should be quite adequate to expose
photoresist.
> 
> I played around with large argon lasers and scanners as a means of
resist 
> exposure rather a long time ago.
> 
> It was difficult to keep things square, the right size and in focus
but the 
> results were still rather acceptable.
> 
> A x-y plotter rig like those used with CO2 laser engravers would be
a much 
> better option and a great deal cheaper.
> 
> You'd probably want to use a considerably longer focal length lense.
> 
> X-Y CO2 laser engravers usually have the collimated laser statically
mounted 
> and shining along one axis hitting a travelling 45 degree mirror which 
> redirects the beam up the other axis to another travelling 45 degree
mirror 
> which in turn directs the beam down onto the work through a focusing
optic.
> 
> 
> DVD laser diodes are probably best mounted on the gantry aimed
directly at the 
> work.
>

It cannot burn copper because of reflection, laser is light and copper is
shiny. I have seen some people trying to paint the copper with black heat
conductive paint, but I never saw the result. You would need quite a
powerful laser anyhow...

________________________________________

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Juan EA7FNJ
Sent: lundi 19 janvier 2009 19:24
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: Burning Laser CNC

Thanks for the answer.

Well, a CO2 laser can engrave the copper directly (I think). But It's
so much more expensive than a DVD-RW laser.

How does a CO2 laser tube cost? I saw How it works and it' so impresive.

2009/1/19 Mark Robinson <mark.robinson@...>:
> Juan EA7FNJ wrote:
>> Hi guys!
>> I''ve seen this: http://c4r0.skrzynka.org/_hv/index.php?page=lasers/cnc2
>>
>> I was thinking: why don't use this kind of laser to burn the
>> photoresist board. After you develop it and ready for the etch. I
>> knoww the CO2 laser but it's more expensive than a simple burn laser
>> from a DVD burner.
>
> A laser from a DVD burner should be quite adequate to expose photoresist.

I think Juan's contemplating burning the resist off, rather than exposing it.
I've got a 25W CO2 laser marker, (google synrad fenix) but no etching
gear here. If anyone wants to send me a bit of photoresist board, I'll
blast a few test images onto it at varying powers and send it back to
you for etching. Working area is credit card size, spot size is 180uM.
It'll almost certainly burn away the etch resist - but I don't know if
it will do odd thermal stuff to the remaining areas, and what the
effective resolution will be. It'll definitely not burn the copper,
with a puny 25W.

('Here' is Cambridge, England)

Steve

Yes, that's right. 

That is my idea: use the DVD laser to expose or burn the resist off. I
don't know if I paint with some black ink a copper board and try to
get off the ink burning it with the laser.

A CO2 laser is very expensive for a student hi hi

--- In Homebrew_PCBs@yahoogroups.com, Steve Wiseman <sjwiseman@...> wrote:
> 
> I think Juan's contemplating burning the resist off, rather than
exposing it.

> I've got a 25W CO2 laser marker, (google synrad fenix) but no etching
> gear here. If anyone wants to send me a bit of photoresist board, I'll
> blast a few test images onto it at varying powers and send it back to
> you for etching. Working area is credit card size, spot size is 180uM.
> It'll almost certainly burn away the etch resist - but I don't know if
> it will do odd thermal stuff to the remaining areas, and what the
> effective resolution will be. It'll definitely not burn the copper,
> with a puny 25W.
> 
> ('Here' is Cambridge, England)
> 
> Steve
>

Steve Wiseman <sjwiseman@...> writes:
> I've got a 25W CO2 laser marker, (google synrad fenix) but no etching

It would be interesting to see how the laser interacts with various
types of spray paint - lacquer, enamel, acrylic, etc - both with
respect to burnability and the resulting resolution.  A thin coat of
flat black laquer, burn off the pattern, etch...

2009/1/19 DJ Delorie <dj@...>:
>
> Steve Wiseman <sjwiseman@...> writes:
>> I've got a 25W CO2 laser marker, (google synrad fenix) but no etching
>
> It would be interesting to see how the laser interacts with various
> types of spray paint - lacquer, enamel, acrylic, etc - both with
> respect to burnability and the resulting resolution. A thin coat of
> flat black laquer, burn off the pattern, etch...

Indeed, I'd like to have a play, but can't quite face the yellow
fingers of etching. Problem is, these days, it's too easy for me to
just mail the gerbers to my local PCB shop and pick up PTH, 6-thou
boards later that day :)
Any PCB homebrewers in Cambridge want to combine efforts for a day,
find out what works and what doesn't? I'll do the lasering (with an
implied promise that I'll do more for you if this works), and you can
do the wet stuff.

Steve

Steve Wiseman wrote:
> 2009/1/19 Mark Robinson <mark.robinson@...>:
>> Juan EA7FNJ wrote:
>>> Hi guys!
>>> I''ve seen this: http://c4r0.skrzynka.org/_hv/index.php?page=lasers/cnc2
>>>
>>> I was thinking: why don't use this kind of laser to burn the
>>> photoresist board. After you develop it and ready for the etch. I
>>> knoww the CO2 laser but it's more expensive than a simple burn laser
>>> from a DVD burner.
>> A laser from a DVD burner should be quite adequate to expose photoresist.
> 
> I think Juan's contemplating burning the resist off, rather than exposing it.
> I've got a 25W CO2 laser marker, (google synrad fenix) but no etching
> gear here. If anyone wants to send me a bit of photoresist board, I'll
> blast a few test images onto it at varying powers and send it back to
> you for etching. Working area is credit card size, spot size is 180uM.
> It'll almost certainly burn away the etch resist - but I don't know if
> it will do odd thermal stuff to the remaining areas, and what the
> effective resolution will be. It'll definitely not burn the copper,
> with a puny 25W.
> 
> ('Here' is Cambridge, England)

Hi,
What precautions are needed for eye protection against stray reflections?

Jerome Decock wrote:
> It cannot burn copper because of reflection, laser is light and copper is
> shiny. I have seen some people trying to paint the copper with black heat
> conductive paint, but I never saw the result. You would need quite a
> powerful laser anyhow...

There's a black coating resist that's designed to be coated on pcb and burnt off
with a laser. It's designed for the laser engravers commonly seen on ebay.

2009/1/20 Russell Shaw <rjshaw@...>:

> Hi,
> What precautions are needed for eye protection against stray reflections?

Closing eyes and looking away does the trick. In any environment where
there was anyone other than me, I'd be rather more rigorous. This is
(obviously) enough power to do serious eye damage.

Steve

I think that is why the Epilogue and such 'boxed lasers' do well.  The 
safety interlocks limit the amount of 'stupid human tricks' that can be 
easily accomplished.

Steve Wiseman wrote:

> 2009/1/20 Russell Shaw <rjshaw@...>:
>
>   
>> Hi,
>> What precautions are needed for eye protection against stray reflections?
>>     
>
> Closing eyes and looking away does the trick. In any environment where
> there was anyone other than me, I'd be rather more rigorous. This is
> (obviously) enough power to do serious eye damage.
>
> Steve
>
>

>
> Hi,
> What precautions are needed for eye protection against stray reflections?

 Not that it's likely to be a problem with low power lasers, but I had
heard (perhaps wrongly) that the vaporized copper can also be VERY
hazardous to the lungs. You just want to be careful.


-- 
carl
--------------------------------------------------------
Henry Carl Ott   N2RVQ    hcarlott@...

Hi guys!

Well, all the videos I'v seen the laser burns black platic or vinyl.
Maybe it's a good point to start the experiments. 

My idea is expose the board using a low cost laser, I think the laser
is better than a UV exposed to get more accuracy.

jmachuca@... / ea7fnj@...

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:

>
> 
> Steve Wiseman <sjwiseman@...> writes:
> > I've got a 25W CO2 laser marker, (google synrad fenix) but no etching
> 
> It would be interesting to see how the laser interacts with various
> types of spray paint - lacquer, enamel, acrylic, etc - both with
> respect to burnability and the resulting resolution.  A thin coat of
> flat black laquer, burn off the pattern, etch...
>

I have tried painting the pcb with different types of paint and burning off 
with a laser, the results are OK, fine lines dont etch well, the burnt off 
paint leaves a transparent residue that needs a good scrubbing with a 
cleaning agent to remove which  affects the painted areas. I prefer the blue 
paper more than any other process,  Couple of bucks per sheet and works all 
the time.

Kim

----- Original Message ----- 

From: "Juan EA7FNJ" <ea7fnj@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, January 19, 2009 10:45 AM
Subject: [Homebrew_PCBs] Re: Burning Laser CNC


> Yes, that's right.
>
> That is my idea: use the DVD laser to expose or burn the resist off. I
> don't know if I paint with some black ink a copper board and try to
> get off the ink burning it with the laser.
>
> A CO2 laser is very expensive for a student hi hi
>
> --- In Homebrew_PCBs@yahoogroups.com, Steve Wiseman <sjwiseman@...> wrote:
>>
>> I think Juan's contemplating burning the resist off, rather than
> exposing it.
>> I've got a 25W CO2 laser marker, (google synrad fenix) but no etching
>> gear here. If anyone wants to send me a bit of photoresist board, I'll
>> blast a few test images onto it at varying powers and send it back to
>> you for etching. Working area is credit card size, spot size is 180uM.
>> It'll almost certainly burn away the etch resist - but I don't know if
>> it will do odd thermal stuff to the remaining areas, and what the
>> effective resolution will be. It'll definitely not burn the copper,
>> with a puny 25W.
>>
>> ('Here' is Cambridge, England)
>>
>> Steve
>>
>
>

--- In Homebrew_PCBs@yahoogroups.com, "Juan EA7FNJ" <ea7fnj@...> wrote:
>
> Hi guys!
> 
> I''ve seen this: http://c4r0.skrzynka.org/_hv/index.php?page=lasers/cnc2
> 
> I was thinking: why don't use this kind of laser to burn the
> photoresist board. After you develop it and ready for the etch. I
> knoww the CO2 laser but it's more expensive than a simple burn laser
> from a DVD burner.
> 
> Any idea? 
> 
> Bye!
>
Hi guys interesting thread,

   For my 2c I use a 40W CO2 Laser (Chinese Engraving one)(2nd Hand
off ebay) to burn of matt black spray paint off brass to make stencils
(ie solder and screen print) and gobos for Theatre lighting bonus of
using spray paint is its not delicate like some of the other coatings
I've tried on brass and copper, you can really scrub the residue off
then hit it with Acid/H2O2 etchant. 
     The thing is the cheap (less than $3000AU) Laser engravers are
Raster devices so to burn the "resist" off a complete board would mean
scanning the entire board too remove the "resist" and experience has
shown me that you need to do it twice to get the best removal, this is
a down side as the laser tubes have a finite life in the low thousands
of hours and are expensive and anything that scans a raster image 1
dot/line at a time is sloooow (I offset the projected cost by making
engraved name tags when I'm not indulging in the hobby)
   On the subject of using CO2 Lasers to "cut" copper as I understand
it the actual mirrors in a CO2 Laser are coated polished copper as the
radiation is in the infrared range so anything strong enough to cut
copper would also burn the mirrors up in the process. I believe that
to cut copper you need to use a YAG Laser and a air/gas jet to blow
the cut material out of the cut.
   I hope this helps
   Regards
   Stephen

At 02:37 PM 1/20/2009, you wrote:

>There's a black coating resist that's designed to be coated on pcb 
>and burnt off
>with a laser. It's designed for the laser engravers commonly seen on ebay.

Give me a link, please.
Cristian 

[Non-text portions of this message have been removed]

2009/1/20 sjlanejan760 <sjlane60@...>:
>Laser engravers are
> Raster devices so to burn the "resist" off a complete board would mean
> scanning the entire board too remove the "resist"

Not all of them - mine's vector, and only kicks down to raster when
it's doing bitmap stuff.

> (I offset the projected cost by making
> engraved name tags when I'm not indulging in the hobby)

Yeah - anodised aluminium marks superbly - I use it for product tags /
serial numbers. It's also handy for burning serial numbers onto the
edges of PCBs...

> On the subject of using CO2 Lasers to "cut" copper as I understand
> it the actual mirrors in a CO2 Laser are coated polished copper as the
> radiation is in the infrared range so anything strong enough to cut
> copper would also burn the mirrors up in the process.

Sort of - but the beam when it goes through the steering optics is
rather wider (and lower power density)  than it is when it finally
hits the target (or, at least, it is in my setup, I don't know about
the gantry systems).

>I believe that
> to cut copper you need to use a YAG Laser and a air/gas jet to blow
> the cut material out of the cut.

That seems to be what the laser-drill PCB shops use.

Steve

--- In Homebrew_PCBs@yahoogroups.com, "sjlanejan760" <sjlane60@...> wrote:
> >
> Hi guys interesting thread,
> 
>    For my 2c I use a 40W CO2 Laser (Chinese Engraving one)(2nd Hand
> off ebay) to burn of matt black spray paint off brass to make stencils

I have seen those chinese laser engravers on ebay and have wondered if
they were worth getting. How well has it worked for you.

Stephen Lane wrote:
   The cheap chinese ones only do raster(something to do with the
built in firmware I've been told) but the more expensive ones do
vector and raster but if the Laser was capable of cutting copper the
cut wouldn't be big enough to get electrical isolation with out some
extra work (at least of multiple offset passes) also I don't think it
would make a wide enough break in a resist to give good access to the
surface by an etchant but what the heck its worth a try thats what
this groups for.
  Good idea that about using the engraver to do serial nos. on the
board, take that to the next level instead of screen printing a
component overlay why not engrave it I'm certainly going to give it a try.

Stephen

Stephen Lane wrote:
    I realize this is off topic slightly but here goes for those that
are thinking of going down this path for making boards etc.
    The one I got had been imported by an Australian Engraving/Screen
Printing Firm and the engraver who owned it before me couldn't get it
to work properly (he said he wasn't a computer literate as he needed
to be) so I got it for a good price I repaired the 10 turn power
control pot and it worked nicely.
    The things you need to watch out for is the packaging as the tube
is fragile and I have heard of them arriving broken and the mirrors
not being aligned also all the connectors in mine were hot glued also
due to a transport issue earlier on in the distributors history.
    CNCZone has a long thread that's worth a read as it follows some
of the trials a tribulations of several of the different versions of
the Chinese Laser instruments.
    Like most of these things you get what you pay for but if you know
what you are doing or are prepared to learn you can tweak it to make
it work quite well.
   One thing to be aware of is there are very few if any safety
interlocks on the cheap ones so you use it with care and don't let
children loose unsupervised the tubes are also water cooled so there
is an added complication of a bucket of water with a modified water
feature pump involved in the proceedings
    When buying one 2nd hand you need to make sure you get all the
bits, mine included the Ventilation Fan, Water pump, software and MOST
IMPORTANT the USB dongle to make it work and a power board and some
sample items (essentially it was complete) I was very pleased for the
$1500AU I paid it was less than 6 months old and new at the time it
should have cost nearly $3000.
    Anyone needing more info can contact me off group unless the
Moderators think this is still close enough to being on topic.

Regards
Stephen
--- In Homebrew_PCBs@yahoogroups.com, "javaguy11111"
<javaguy11111@...> wrote:

>
> --- In Homebrew_PCBs@yahoogroups.com, "sjlanejan760" <sjlane60@> wrote:
> > >
> > Hi guys interesting thread,
> > 
> >    For my 2c I use a 40W CO2 Laser (Chinese Engraving one)(2nd Hand
> > off ebay) to burn of matt black spray paint off brass to make stencils
> 
> I have seen those chinese laser engravers on ebay and have wondered if
> they were worth getting. How well has it worked for you.
>