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Laser cutting for DIY PCB

Laser cutting for DIY PCB

2011-07-06 by kbshankar2000

I am interested in knowing how many of you have experimented with a
laser cutter for DIY PCB?
Would love to hear what kind of experiences you have had.
This method does away with worrying about a laminiator and laser printer
but in this case too, just like toner and paper's critcal for toner
transfer, the choice of spray is extremely imporant!
For those who have good experiences using a laser cutter, could you
share the details of the spray used?
From what I have read, bad choice of a spray can generate the following
issues in the least:
- melts with the laser and cools over the traces which were just
engraved, ruins everything
- is very difficult to remove using acetone or thinner (even after
etching) in order to solder on the traces; requires to be scrubbed off
(potentially damaging very thin traces)
- evaporates but leaves behind a film/residue on the board that is
resistant to etching (some can be removed with alcohol/acetone) This
last issue has been well documented on this picture set:

http://groups.yahoo.com/group/Homebrew_PCBs/photos/album/540603270/pic/5\
51305033/view?picmode
<http://groups.yahoo.com/group/Homebrew_PCBs/photos/album/540603270/pic/\
551305033/view?picmode>
What vers5d did first was spray the copper clad with some Rustoleum
paint: something like http://www.rustoleum.com/CBGProduct.asp?pid=95
<http://www.rustoleum.com/CBGProduct.asp?pid=95> . The picture
"Before etching" is what he got *after* using the laser cutter to "cut
away" that spray on resist from places that needs to be etched later.
(This is the reverse process of toner transfer/plot. Pretty
timeconsuming I believe. Perhaps making a pattern like that used in
isolation milling would require less time?)
Then he wiped the right hand portion of the PCB with some acetone, thus
clearing away the spray residue.
After this he proceeded to etch the board to get "After etching"
"After cleaned" is what he got after scrubbing the board after it was
etched
I agree with his observation "With the right resist and some adjustment
for the laser's dot size. It should work nicely."
I am interested in taking this further and would entertain exchange from
others who are interested likewise.



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

Re: Laser cutting for DIY PCB

2011-07-07 by hotsnausage

We basically use this process, but we use a different Rustoleum product and it works fine.

Don't forget to take into account the width of the laser beam when laying out your traces. Don't layout any traces less than 16mil, because you'll only have 6-8mil left after lazing. Also, spray on only enough paint to cover the board, otherwise that's more airborne, burnt paint that will land and fuse back on the board.

-e

Show quoted textHide quoted text
--- In Homebrew_PCBs@yahoogroups.com, "kbshankar2000" <kbshankar2000@...> wrote:
>
> I am interested in knowing how many of you have experimented with a
> laser cutter for DIY PCB?
> ...
>

Re: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-07 by Kamal Shankar

> We basically use this process, but we use a different Rustoleum product and it works fine.

Excellent. Could you share the name/picture/link of that product please?

I will buy it myself and try out the product and report back.

> Don't forget to take into account the width of the laser beam when laying out your traces. Don't layout any traces less than 16mil, because you'll only have 6-8mil left after lazing.

I am not sure where to get the width of the laser beam. Do they mention these in the machine's manual?

Show quoted textHide quoted text
> Also, spray on only enough paint to cover the board, otherwise that's more airborne, burnt paint that will land and fuse back on the board.


Don't you use a ventilator? The cutter I use is directly connected to a vacuuming ventilator. Anything that is airborne should be sucked right out?

I was looking forward to such feedback!

Thanks.

Re: Laser cutting for DIY PCB

2011-07-08 by Jeanette

We use a 2.5kW CO2 laser for embossing -- in our application it's very important to use a ventilator -- elsewise the "contrastiness" is impaired -- just as if you were using a camera with a dab of finger grease on the lense.

Show quoted textHide quoted text
--- In Homebrew_PCBs@yahoogroups.com, "hotsnausage" <hotsnausage@...> wrote:
>
> We basically use this process, but we use a different Rustoleum product and it works fine.
>
> Don't forget to take into account the width of the laser beam when laying out your traces. Don't layout any traces less than 16mil, because you'll only have 6-8mil left after lazing. Also, spray on only enough paint to cover the board, otherwise that's more airborne, burnt paint that will land and fuse back on the board.
>
> -e
>
> --- In Homebrew_PCBs@yahoogroups.com, "kbshankar2000" <kbshankar2000@> wrote:
> >
> > I am interested in knowing how many of you have experimented with a
> > laser cutter for DIY PCB?
> > ...
> >
>

Re: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-08 by Mark Mickelsen

2.5kW!!! Wow! Do you shoot down incoming enemy missiles in your spare time?

Show quoted textHide quoted text
On Fri, Jul 8, 2011 at 5:49 AM, Jeanette <jdwalton@...> wrote:

> **
>
>
> We use a 2.5kW CO2 laser for embossing -- in our application it's very
> important to use a ventilator -- elsewise the "contrastiness" is impaired --
> just as if you were using a camera with a dab of finger grease on the lense.
>
> --- In Homebrew_PCBs@yahoogroups.com, "hotsnausage" <hotsnausage@...>
> wrote:
> >
> > We basically use this process, but we use a different Rustoleum product
> and it works fine.
> >
> > Don't forget to take into account the width of the laser beam when laying
> out your traces. Don't layout any traces less than 16mil, because you'll
> only have 6-8mil left after lazing. Also, spray on only enough paint to
> cover the board, otherwise that's more airborne, burnt paint that will land
> and fuse back on the board.
> >
> > -e
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "kbshankar2000" <kbshankar2000@>
> wrote:
> > >
> > > I am interested in knowing how many of you have experimented with a
> > > laser cutter for DIY PCB?
> > > ...
> > >
> >
>
>
>


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

Re: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-08 by Kamal Shankar

Using a 2.5kW CO2 laser you could probably directly cut the copper layer of the PCB without any need to etch it!

What kind of paint do you use as a resist?



Show quoted textHide quoted text
>________________________________
>From: Jeanette <jdwalton@...>
>To: Homebrew_PCBs@yahoogroups.com
>Sent: Friday, July 8, 2011 4:49 AM
>Subject: [Homebrew_PCBs] Re: Laser cutting for DIY PCB
>
>
>
>We use a 2.5kW CO2 laser for embossing -- in our application it's very important to use a ventilator -- elsewise the "contrastiness" is impaired -- just as if you were using a camera with a dab of finger grease on the lense.

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

RE: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-08 by Tony Smith

> Using a 2.5kW CO2 laser you could probably directly cut the copper
> layer of the PCB without any need to etch it!
>
> What kind of paint do you use as a resist?


Copper is quite difficult for a CO2 laser to cut - though 2.5kW should do
it.

FWIW:
http://www.lpkf.com/products/rapid-pcb-prototyping/laser-circuit-structuring
/laser-structuring-printed-circuit-boards.htm

Very very impressive.

That would be a YAG laser, YAG being better for metals than CO2.

No, you can't afford it even accounting for the recent price drop.

Tony

Re: Laser cutting for DIY PCB

2011-07-09 by hotsnausage

> Excellent. Could you share the name/picture/link of that product please?
>
> I will buy it myself and try out the product and report back.

Rustoleum Painter's Touch Ultra Cover 2X - Black

> I am not sure where to get the width of the laser beam. Do they mention these in the machine's manual?

Almost certainly. Our does.

Show quoted textHide quoted text
> Don't you use a ventilator? The cutter I use is directly connected to a vacuuming ventilator. Anything that is airborne should be sucked right out?

Sure, but if you have any control over yours, the more the better.

After you burn the paint off, we use a isopropyl alcohol on a cotton ball to gently remove anything that's loosely stuck to the board, especially over the copper that was burned-off.

And use raster mode, rather than vector mode.

-e

Re: Laser cutting for DIY PCB

2011-07-09 by Jeanette

it's used to cut patterns into wood panels -- so folks can put their trademark or brand identification on before finishing. It's about the size of a refrigerator, and -- doesn't use servo's. Obviously you have to adjust the cutting speed and the removal of debris and smoke to get the kind of resolution you need.


Show quoted textHide quoted text
--- In Homebrew_PCBs@yahoogroups.com, Kamal Shankar <kbshankar2000@...> wrote:
>
> Using a 2.5kW CO2 laser you could probably directly cut the copper layer of the PCB without any need to etch it!
>
> What kind of paint do you use as a resist?
>
>
>
> >________________________________
> >From: Jeanette <jdwalton@...>
> >To: Homebrew_PCBs@yahoogroups.com
> >Sent: Friday, July 8, 2011 4:49 AM
> >Subject: [Homebrew_PCBs] Re: Laser cutting for DIY PCB
> >
> >
> >
> >We use a 2.5kW CO2 laser for embossing -- in our application it's very important to use a ventilator -- elsewise the "contrastiness" is impaired -- just as if you were using a camera with a dab of finger grease on the lense.
>
> [Non-text portions of this message have been removed]
>

Re: Laser cutting for DIY PCB

2011-07-10 by hotsnausage

> I can't find what a kind of laser is used for that? (paint burning)

We happen to be using a 60W CO2 laser cutter, but you may be able to do it very successfully with less power.

Re: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-10 by Slavko Kocjancic

S, hotsnausage piše:
>> I can't find what a kind of laser is used for that? (paint burning)
> We happen to be using a 60W CO2 laser cutter, but you may be able to do it very successfully with less power.
>
Ouch 60W.

I just thinking about 1/4W (DVD or BLURAY) laser. If something can be
done with that. (But probably is just enought for photoresist to develop.)

Re: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-10 by Mark Lerman

You can get a 1-3 watt laser with a fiberoptic
output that does not need a focusing lens if the
fiber is kept close to the pcb for not too much
money - see ebay. Whether it will burn fast enough is another question.

At 02:41 AM 7/10/2011, you wrote:
Show quoted textHide quoted text
>S, hotsnausage piše:
> >> I can't find what a kind of laser is used for that? (paint burning)
> > We happen to be using a 60W CO2 laser cutter,
> but you may be able to do it very successfully with less power.
> >
>Ouch 60W.
>
>I just thinking about 1/4W (DVD or BLURAY) laser. If something can be
>done with that. (But probably is just enought for photoresist to develop.)
>
>
>------------------------------------
>
>Be sure to visit the group home and check for new Links, Files, and Photos:
>http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>

Re: Laser cutting for DIY PCB

2011-07-10 by Stephen

Stephen Lane wrote:
As a by the by a CO2 Laser won't touch copper its not the right wavelength also copper makes such a good heatsink it sucks the heat right out of the beam (CO2 Beam is an infra red one) as to resist I have use plain black matt pressure pack spray paint to create brass stencils by this method it is a little hit and miss in that the paint sometimes does not evaporate cleanly but if you wipe it over with a paint thinner quickly you can tidy it up. Then I etch it with the acid/peroxide etchant the paint is reasonably etch resistant to this & I have also had great results with the persuphate etchant as well.
I use a 40W CO2 Laser for this

Regards
Stephen Lane

Show quoted textHide quoted text
--- In Homebrew_PCBs@yahoogroups.com, Mark Lerman <mlerman@...> wrote:
>
>
> You can get a 1-3 watt laser with a fiberoptic
> output that does not need a focusing lens if the
> fiber is kept close to the pcb for not too much
> money - see ebay. Whether it will burn fast enough is another question.
>
> At 02:41 AM 7/10/2011, you wrote:
> >S, hotsnausage piše:
> > >> I can't find what a kind of laser is used for that? (paint burning)
> > > We happen to be using a 60W CO2 laser cutter,
> > but you may be able to do it very successfully with less power.
> > >
> >Ouch 60W.
> >
> >I just thinking about 1/4W (DVD or BLURAY) laser. If something can be
> >done with that. (But probably is just enought for photoresist to develop.)
> >
> >
> >------------------------------------
> >
> >Be sure to visit the group home and check for new Links, Files, and Photos:
> >http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
>

Re: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-10 by Kamal Shankar

>beam (CO2 Beam is an infra red one) as to resist I have use plain black matt pressure pack spray paint to create brass stencils by this method it is a little hit and miss in that the paint sometimes does not evaporate cleanly but if you wipe it over with a paint thinner quickly you can tidy it up. Then I
>

Hmm.. so it seems that getting a spray paint that does not leave any residue behind after laser cutting is extremely difficult to find!

One member, either here or some other forum, had posted that they had found a paint that left no residue, but I did not get any answer when I asked for a model number.


Show quoted textHide quoted text
> etch it with the acid/peroxide etchant the paint is reasonably etch resistant to this & I have also had great results with the persuphate etchant as well.
>I use a 40W CO2 Laser for this
>

When you say "reasonably etch resistant", does it mean you get pitting on lost thin traces?

Also - I noticed that Home Depot carries "Acetone" and "Paint thinner" as two separate bottles.

Is there a difference between the two regarding using them to clean up residue from a laser cut board?

RE: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-10 by Jeff Heiss

Maybe PVC primer (the purple stuff) would work as an alterative to spray
paint.



Jeff



_____

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Kamal Shankar
Sent: Sunday, July 10, 2011 4:44 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] Re: Laser cutting for DIY PCB






>beam (CO2 Beam is an infra red one) as to resist I have use plain black
matt pressure pack spray paint to create brass stencils by this method it is
a little hit and miss in that the paint sometimes does not evaporate cleanly
but if you wipe it over with a paint thinner quickly you can tidy it up.
Then I
>

Hmm.. so it seems that getting a spray paint that does not leave any residue
behind after laser cutting is extremely difficult to find!

One member, either here or some other forum, had posted that they had found
a paint that left no residue, but I did not get any answer when I asked for
a model number.

> etch it with the acid/peroxide etchant the paint is reasonably etch
resistant to this & I have also had great results with the persuphate
etchant as well.
>I use a 40W CO2 Laser for this
>

When you say "reasonably etch resistant", does it mean you get pitting on
lost thin traces?

Also - I noticed that Home Depot carries "Acetone" and "Paint thinner" as
two separate bottles.

Is there a difference between the two regarding using them to clean up
residue from a laser cut board?





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

RE: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-10 by Tony Smith

> >beam (CO2 Beam is an infra red one) as to resist I have use plain
> black matt pressure pack spray paint to create brass stencils by this
> method it is a little hit and miss in that the paint sometimes does not
> evaporate cleanly but if you wipe it over with a paint thinner quickly
> you can tidy it up. Then I
> >
>
> Hmm.. so it seems that getting a spray paint that does not leave any
> residue behind after laser cutting is extremely difficult to find!
>
> One member, either here or some other forum, had posted that they had
> found a paint that left no residue, but I did not get any answer when I
> asked for a model number.


You need this: http://www.cermarc.com/. There's another spray that brushes
off (this one needs water) or use the tape.. See www.laserbits.com for
prices.

Tony

Re: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-10 by Kamal Shankar

Thanks Tony!

For reference, this is the product page : http://www.laserbits.com/index.php?main_page=product_info&cPath=356_487&products_id=235

The video on the page reminds me of the photoresist method - but a bit easier.

I will try my luck with those $10 Rustoleum spray cans and if the results are very poor, give this $70 can a try.

Show quoted textHide quoted text
>________________________________
>From:Tony Smith <ajsmith1968@...>
>To:Homebrew_PCBs@yahoogroups.com
>Sent:Sunday, July 10, 2011 3:18 PM
>Subject:RE: [Homebrew_PCBs] Re: Laser cutting for DIY PCB
>
>
>You need this: http://www.cermarc.com/. There's another spray that brushes
>off (this one needs water) or use the tape.. See www.laserbits.comfor
>prices.
>
>Tony
>

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

RE: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-11 by Tony Smith

> Also - I noticed that Home Depot carries "Acetone" and "Paint thinner"
> as two separate bottles.
>
> Is there a difference between the two regarding using them to clean up
> residue from a laser cut board?


There are other paint thinners beside acetone, could be turpentine, MEK,
etc.

Acetone should take the paint off, as usual it depends on the type of paint.
Thinners would probably work too. Try it and see, you have an advantage as
the paint is still fresh so it won't take too much effort, especially if you
mask off where the laser won't go.

Paint strippers won't damage the metal, they're solvents, not acids. That
citrus stuff works well.

Tony

Re: Laser cutting for DIY PCB

2011-07-11 by Stephen

Stephen Lane wrote:
Yes it is hard to find a paint that evaporates cleanly, I haven't found one yet but I agree that good extraction or whats called air assist would probably help alot but I haven't been able to make that work on my laser (yet).
By paint thinner I mean what ever is the thinner for the paint you use for most tinned spray paint MEK or Acetone will work the point is if the paint has gone on relativly thick after its been Lased off the residue is very thin so a quick wipe with whatever thinner works usually cleans it off without taking the lot off.

The Cermark paint listed in this thread allows a CO2 Laser to mark metal but I wouldn't bet on the marking being etch resistant but I would love to hear if it is it would make doing this alot easier.

By reasonably etch resistant is as you allude to it will lift easily causing pits etc with the Acid/H2O2 mix but some times depending on the amount to etch off its not in it long enough to matter.

I hope that helps

Regards
Stephen



Show quoted textHide quoted text
--- In Homebrew_PCBs@yahoogroups.com, Kamal Shankar <kbshankar2000@...> wrote:
>
>
> >beam (CO2 Beam is an infra red one) as to resist I have use plain black matt pressure pack spray paint to create brass stencils by this method it is a little hit and miss in that the paint sometimes does not evaporate cleanly but if you wipe it over with a paint thinner quickly you can tidy it up. Then I
> >
>
> Hmm.. so it seems that getting a spray paint that does not leave any residue behind after laser cutting is extremely difficult to find!
>
> One member, either here or some other forum, had posted that they had found a paint that left no residue, but I did not get any answer when I asked for a model number.
>
>
> > etch it with the acid/peroxide etchant the paint is reasonably etch resistant to this & I have also had great results with the persuphate etchant as well.
> >I use a 40W CO2 Laser for this
> >
>
> When you say "reasonably etch resistant", does it mean you get pitting on lost thin traces?
>
> Also - I noticed that Home Depot carries "Acetone" and "Paint thinner" as two separate bottles.
>
> Is there a difference between the two regarding using them to clean up residue from a laser cut board?
>

Re: [Homebrew_PCBs] Re: Laser cutting for DIY PCB

2011-07-11 by Kamal Shankar

>Stephen Lane wrote:

>Yes it is hard to find a paint that evaporates cleanly, I haven't found one yet but I agree that good extraction or whats called air assist would probably help alot but I haven't been able to make that work on my laser (yet).

Eric has been helping me out a lot recently, regarding the paint that works very well for him.

We think it might be this, but he doesn't have the paint at hand yet to verify:

http://www.rustoleum.com/CBGProduct.asp?pid=415


Show quoted textHide quoted text
>By paint thinner I mean what ever is the thinner for the paint you use for most tinned spray paint MEK or Acetone will work the point is if the paint has gone on relativly thick after its been Lased off the residue is very thin so a quick wipe with whatever thinner works usually cleans it off without taking the lot off.
>


Eric also told me that IPA works well to clean off the residue!

I am not very sure about the conc. of the IPA required yet - have read that conc. lower than 99% tends to leave a white reside behind on the copper clad.