Homebrew PCBs

Hi guys,

I am looking for some ideas on work holding for PCBs.  I plan to do 
drilling and probably some isolation milling with my CNC machine.  
So far I have made good progress on most apsects of the machine's 
design, but the one thing that continues to elude me is the work 
holding.

I would think that there should be a waste or spoil board under the 
PCB that is being machined - this is normal in other similar 
applications.  So, I figure I would use masonite or other similar 
and cheap material.

Of the very few photos I have seen for workholding, the only two 
methods I have seen so far are

1) Basic toe clamps which clamp the work down to the table. Simple 
and effective, but would prefer something more elegant

2) Some sort of clamping system that comes in from the edges.  This 
is appealing as it can be made for short in height.  

Both examples have limitations and such so I am looking for any and 
all ideas. If you have any suggestions or know of any photos showing 
PCB clamping, I sure would appreciate a link to the photos.

Chris

magnets or vacuum can work well.
I can expand this answer if you are interested.
AGSC

On 2006-Aug 28, at 06:01hrs AM, lcdpublishing wrote:

Hi guys,

I am looking for some ideas on work holding for PCBs. I plan to do
drilling and probably some isolation milling with my CNC machine.
So far I have made good progress on most apsects of the machine's
design, but the one thing that continues to elude me is the work
holding.

I would think that there should be a waste or spoil board under the
PCB that is being machined - this is normal in other similar
applications. So, I figure I would use masonite or other similar
and cheap material.

Of the very few photos I have seen for workholding, the only two
methods I have seen so far are

1) Basic toe clamps which clamp the work down to the table. Simple
and effective, but would prefer something more elegant

2) Some sort of clamping system that comes in from the edges. This
is appealing as it can be made for short in height.

Both examples have limitations and such so I am looking for any and
all ideas. If you have any suggestions or know of any photos showing
PCB clamping, I sure would appreciate a link to the photos.

Chris




^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AGSC  Augustus Gustavius Salvatore Calabrese
4337 Raleigh Street
Denver, CO
720 222 1309     303 908 7716 cell
adding " spam2006 " bypasses my spam blocker.  Please place in the  
text or at the END of the subject line.
( i am hard to reach by phone )
All ideas, text, drawings and audio , that are originated by me,  and  
included with this signature text are to be deemed to be released to  
the public domain as of the date of this communication .  AGSC
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^




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

Hi Gus,

I sure am interested!  Vacuum could be a problem on this machines as 
I don't have room though.  However, magnets is an interesting idea I 
have not seen used - that one has my interest!  Please expand on it 
if you don't mind.

Chris



--- In Homebrew_PCBs@yahoogroups.com, Gus S Calabrese <gsc@...> 
wrote:
>
> magnets or vacuum can work well.
> I can expand this answer if you are interested.
> AGSC
> 
> On 2006-Aug 28, at 06:01hrs AM, lcdpublishing wrote:
> 
> Hi guys,
> 
> I am looking for some ideas on work holding for PCBs. I plan to do
> drilling and probably some isolation milling with my CNC machine.
> So far I have made good progress on most apsects of the machine's
> design, but the one thing that continues to elude me is the work
> holding.
> 
> I would think that there should be a waste or spoil board under the
> PCB that is being machined - this is normal in other similar
> applications. So, I figure I would use masonite or other similar
> and cheap material.
> 
> Of the very few photos I have seen for workholding, the only two
> methods I have seen so far are
> 
> 1) Basic toe clamps which clamp the work down to the table. Simple
> and effective, but would prefer something more elegant
> 
> 2) Some sort of clamping system that comes in from the edges. This
> is appealing as it can be made for short in height.
> 
> Both examples have limitations and such so I am looking for any and
> all ideas. If you have any suggestions or know of any photos 
showing
> PCB clamping, I sure would appreciate a link to the photos.
> 
> Chris
> 
> 
> 
> 
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> AGSC  Augustus Gustavius Salvatore Calabrese
> 4337 Raleigh Street
> Denver, CO
> 720 222 1309     303 908 7716 cell
> adding " spam2006 " bypasses my spam blocker.  Please place in 
the  
> text or at the END of the subject line.
> ( i am hard to reach by phone )
> All ideas, text, drawings and audio , that are originated by me,  
and  
> included with this signature text are to be deemed to be released 
to  

> the public domain as of the date of this communication .  AGSC
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>

> -----Message d'origine-----
> De : Homebrew_PCBs@yahoogroups.com 
> [mailto:Homebrew_PCBs@yahoogroups.com] De la part de lcdpublishing
> Envoyé : août 28 2006 08:35
> À : Homebrew_PCBs@yahoogroups.com
> Objet : [Homebrew_PCBs] Re: Looking for ideas - Work holding 
> for PCB drilling/routing?
> 
> 
> Hi Gus,
> 
> I sure am interested!  Vacuum could be a problem on this machines as 
> I don't have room though.  However, magnets is an interesting idea I 
> have not seen used - that one has my interest!  Please expand on it 
> if you don't mind.
> 
> Chris


Does the copper on the PCB remained magnetized like iron?  That would not be
a good thing when you start putting ICs on it.

What about drilling the mounting holes manually and using wood screws to
mount the PCB on MDF?  Or maybe have bolts mounted through the MDF like
alignment pins, and then put a nut to hold the PCB down?  Cut the bolts so
they stick out just enough for the nut to fasten securely.

Robert
:)

On Mon, 28 Aug 2006 15:30:49 +0200, Robert Hedan  
<robert.hedan@...> wrote:

>
> Does the copper on the PCB remained magnetized like iron?  That would  
> not be
> a good thing when you start putting ICs on it.


lol! good one ;-)

ST

In a message dated 8/28/2006 7:02:09 A.M. Central Daylight Time,  
lcdpublishing@... writes:

Both  examples have limitations and such so I am looking for any and 
all ideas.  If you have any suggestions or know of any photos showing 
PCB clamping, I  sure would appreciate a link to the photos.



It's not "elegant" but it WORKS!  It takes up (almost) NO  space, does not 
interfere in ANY way with the drilling nor quill-stuff, is  acceptably cheap, 
quick, leaves no non-removeable muss, etc:  Scotch  double-sided "Poster Tape" 
aka "Wall Saver" removeable clear tape.  I buy  it in cartons!
 
But you gotta use either waste PCB stock or "Formica" for  backing, also held 
down to your drilling-machine's surface with GOOD  double-stick tape, cause 
that won't stick to "Masonite" very well.   Relative to PCB stock, scraps of 
"Formica" ("Resopal" in other lands, I think?)  is very cheap.  Find a good 
"Kitchen-cabinet shop" and see if they don't  just THROW OUT lots of that!        
Jan  Rowland


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

On Mon, 28 Aug 2006 20:26:28 +0200, <JanRwl@...> wrote:

> "Resopal" in other lands, I think?


Yes indeed, and as you say it is plentiful and often free.

Only complaint i have is sometimes it is bent and will not stay flat  
whatever you do.
Had this problem with the inkjet carrier, had to make a new one the other  
side up.

BTW i got the dial indicator today i wanted to use to adjust the inkjet  
head height precisely the same both ends, but so far i don't have much  
luck with using it...

ST

To start with, it is possible to build or buy a magnetic clamp that
moves the magnet into contact with metal mag feed routers or moves
the magnet away so the piece is released.

I have purchased neodymium magnets which are awesome for size
and holding power.  I will mail you one if you would like to play  
with it.


It is also possible to use an electromagnet to hold parts down.  That  
sucks power
however.

Here are some photos from Harborfreight.com that may help

 5645-0VGA
Cen-Tech 	MULTI-POSITION MAGNETIC BASE WITH FINE ADJUSTMENT
$18


 5646-4VGA
Cen-Tech 	MULTI-POSITION MAGNETIC BASE
$13

 33487-2VGA
	MAGNETIC CHUCK   $100

 90504-0VGA
	8'' x 4'' MAGNETIC CHUCK
$60






On 2006-Aug 28, at 06:34hrs AM, lcdpublishing wrote:

Hi Gus,

I sure am interested! Vacuum could be a problem on this machines as
I don't have room though. However, magnets is an interesting idea I
have not seen used - that one has my interest! Please expand on it
if you don't mind.

Chris

--- In Homebrew_PCBs@yahoogroups.com, Gus S Calabrese <gsc@...>
wrote:
 >
 > magnets or vacuum can work well.
 > I can expand this answer if you are interested.
 > AGSC
 >
 > On 2006-Aug 28, at 06:01hrs AM, lcdpublishing wrote:
 >
 > Hi guys,
 >
 > I am looking for some ideas on work holding for PCBs. I plan to do
 > drilling and probably some isolation milling with my CNC machine.
 > So far I have made good progress on most apsects of the machine's
 > design, but the one thing that continues to elude me is the work
 > holding.
 >
 > I would think that there should be a waste or spoil board under the
 > PCB that is being machined - this is normal in other similar
 > applications. So, I figure I would use masonite or other similar
 > and cheap material.
 >
 > Of the very few photos I have seen for workholding, the only two
 > methods I have seen so far are
 >
 > 1) Basic toe clamps which clamp the work down to the table. Simple
 > and effective, but would prefer something more elegant
 >
 > 2) Some sort of clamping system that comes in from the edges. This
 > is appealing as it can be made for short in height.
 >
 > Both examples have limitations and such so I am looking for any and
 > all ideas. If you have any suggestions or know of any photos
showing
 > PCB clamping, I sure would appreciate a link to the photos.
 >
 > Chris
 >
 >
 >
 >
 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 > AGSC Augustus Gustavius Salvatore Calabrese
 > 4337 Raleigh Street
 > Denver, CO
 > 720 222 1309 303 908 7716 cell
 > adding " spam2006 " bypasses my spam blocker. Please place in
the
 > text or at the END of the subject line.
 > ( i am hard to reach by phone )
 > All ideas, text, drawings and audio , that are originated by me,
and
 > included with this signature text are to be deemed to be released
to
 > the public domain as of the date of this communication . AGSC
 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 >
 >
 >
 >
 > [Non-text portions of this message have been removed]
 >




^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AGSC  Augustus Gustavius Salvatore Calabrese
4337 Raleigh Street
Denver, CO
720 222 1309     303 908 7716 cell
adding " spam2006 " bypasses my spam blocker.  Please place in the  
text or at the END of the subject line.
( i am hard to reach by phone )
All ideas, text, drawings and audio , that are originated by me,  and  
included with this signature text are to be deemed to be released to  
the public domain as of the date of this communication .  AGSC
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^




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

> LCD PUB wrote:
>
> I am looking for some ideas on work holding
> for PCBs.  I plan to do drilling and probably
> some isolation milling with my CNC machine.  
> So far I have made good progress on most
> apsects of the machine's design, but the one
> thing that continues to elude me is the work 
> holding.

Thick double sided tape

Something else that is used for holding down
metal parts is a mixture of wax and crushed
up beatles (shellac).  It is used kinda like
hot melt glue but much stronger.

Or if you are only ever planing on doing one
sized board it would be easy to make up a jig
with finger clamps built onto the sides.

>If you have any suggestions or know of any photos showing
>PCB clamping, I sure would appreciate a link to the photos.

This photo was taken over a year ago. Since then I've dispensed with 
the square jig and use the T-slot/bolt/washer combo on both sides of 
the MDF. Cheap 3/4" masking tape around the edges holds the PCB to the 
MDF. Originally, it was intended to be just a temporary solution but 
it worked so well that I couldn't be bothered with anything more 
elaborate.

http://www.pbase.com/eldata/image/65932023

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing" 
<lcdpublishing@...> wrote:
>

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing" 
<lcdpublishing@...> wrote:
>
> Hi guys,
> 
> I am looking for some ideas on work holding for PCBs.  I plan to do 
> drilling and probably some isolation milling with my CNC machine.  
> 
> Chris
>


Chris,

I can't advise you right off, but you MIGHT want to check in at 
the "PCB-Gcode" group, 
[http://groups.yahoo.com/group/pcb-gcode/?yguid=219383207]
or [http://www.cnczone.com/] try the "Forums" for Lots of CNC answers.

Thanks for all the suggestions guys!

Tape is something I have used on my big CNC wood router and it has 
worked very good there.  While I do have vacuum clamping on it, 
sometimes you can use a vacuum (too many holes etc.). I have found 
that carpet tape (double sided) works really good and I have also used 
regular masking tape along the edges.

Could it be that plain ole tape is the elegant solution I am seeking ;-
)

Thanks again!

Chris

On Tue, 29 Aug 2006 14:18:05 +0200, lcdpublishing  
<lcdpublishing@...> wrote:

> Thanks for all the suggestions guys!
> Tape is something I have used on my big CNC wood router and it has
> worked very good there.  While I do have vacuum clamping on it,
> sometimes you can use a vacuum (too many holes etc.). I have found
> that carpet tape (double sided) works really good and I have also used
> regular masking tape along the edges.
> Could it be that plain ole tape is the elegant solution I am seeking ;-
> )
> Thanks again!
> Chris


Tape is great for trying something, but if you are going to do many a  
clamp is more convenient.

For the PCB printer i had to make a very low in height clamping mechanism  
so it will fit under the head.
Also, it had to allow any size PCB.

Luckily the clamping requirements are not high, and it is sufficient to  
hold the PCB from the sides (although it would be easily possible to add a  
bit of thin material tricking over the edge so it prevents the PCB from  
lifting).

Anyway, i just used glued a strip of PCB along the front edge, and a  
second wider strip had a slot cut along the center but not all the way to  
the ends. This slot is used to screw the strip down with a screw with a  
very flat head, just enough so i can just slide the strip with some good  
resistance. The thing is used by simply dropping in the PCB against the  
front guide, and then sliding the other srtip against the other edge of  
the PCB.
Works very well, and is a whole lot more convenient than the tape i  
previously used.


You may be able to use a similar setup using steel strips slightly thicker  
than the PCB and grinding the edge so it slopes backwards and securely  
holds the PCB in place and down at the same time.

ST