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Subject: Re: [Homebrew_PCBs] Re: Alternate Masking Materials (CO2 Laser)

From: Andrew Villeneuve <andrewmv@...>
Date: 2010-12-30

I've heard that the diode lasers in consumer DVD-R drives can pop
balloons...I'm not an expert, but it seems feasible that it could evaporate
a thin layer of paint with a slow enough pass.

In fact, it'd already be mounted on a single axis of movement with
absolutely overkill resolution, with a fairly sophisticated dynamically
adjustable lens assembly. Hmmm...

-Andrew

On Wed, Dec 29, 2010 at 11:33 AM, Mark Lerman <mlerman@...> wrote:

>
>
>
> I don't know a whole lot about lasers, so forgive my ignorance. Is
> there another type of laser than CO2 that will work for this purpose?
> These CO2 lasers seem mostly to be for engraving whereas just cutting
> through a very thin layer of paint wouldn't seem to require so much
> power, especially since the time isn't critical. I have a cnc mill
> that I'd like to mount a laser on, but I'd really prefer a small
> solid state laser if possible.
>
>
> Mark
>
> At 09:00 AM 12/29/2010, you wrote:
> >We've been using the paint method to do boards for a few months now,
> >and it's been working pretty well. If you need top-notch detail,
> >then you need to go with a photoresist solution. 10mil/10mil is
> >pretty easy to do repeatably.
> >
> >The key thing to remember that the laser is about 8mil wide. This
> >will affect the width of the traces and isolation that you lay out,
> >because you'd end up with less and more, respectively.
> >
> >We have noticed the re-adhesion behavior mentioned below, but if you
> >reduce the paint to the minimum needed for coverage, the amount of
> >airborne burnt-off paint will be correspondingly reduced. Burning
> >from the far side of the board probably couldn't hurt. We clean
> >lasered boards gently with IPA and a cotton ball before etching.
> >
> >We've gone from bare copper clad board to etched-undrilled in about
> >30 minutes with fresh etchant (FeCl). Assuming that you have access
> >to a laser printer, the ease+cost can't be beat (you might be able
> >to do cheaper by hand-drawing or plotting with a resist pen
> >though). But you won't be running two traces in between
> >0.1"-centered holes either, so there's still a place for photoresist
> >in the world.
> >
> >We haven't done any soldermasking, but if you find something that
> >works well for you, let us all know.
> >
> >-eric
> >
> >
> >
> >
> >------------------------------------
>
> >
> >Be sure to visit the group home and check for new Links, Files, and
> Photos:
> >http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
>
>
>


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