Homebrew PCBs

"Larry Battraw" <lbattraw@...> writes:
> Do you have a detailed description of your process, end-to-end?

Not really.

> How do you make your transparencies?  You mentioned you use Silkjet
> but what type of printer do you use at what DPI?  Do you use the
> manufacturer's ink or refilled/third-party ink?

It's an Epson R280 at 2880x2880 dpi.  It goes to 5760x2880 but the
software prefers a 1:1 aspect ratio.  I'm using the Epson "claria"
ink, black.  I haven't tried the other colors yet.

So far, I've used Silkjet and Jetstar regular with equal results.  I
just got some Jetstar Premium but haven't had a chance to test it yet.

You have to use the correct side of the paper, too.

> I've also tried a Epson Stylus 860 which is amazingly good at
> solid, perfectly black printouts with the density in Gutenprint set to
> 4.0 like you detail on your web page.

Yup, the 4.0 setting pretty much forces each image pixel to become an
ink drop, giving you a really dark image.  You need the special paper
for that, else it bleeds all over the place.

> How do you laminate your boards?

I'm using Adam's wet-lamination technique:
http://members.optusnet.com.au/~eseychell/PCB/photoresist/index.html

My laminator is too hot for the film I've got.

The only thing I do different is, when I've got the transparency over
everything, I hold it firmly with one hand and squeegue *hard* with
the other, which pretty much removes all the water.  Then I just need
to squeegee it a little during heating to avoid bubbles.

> How do you expose your boards?

I've built a UV exposure box using LEDs:
http://www.delorie.com/pcb/uvled/

I put the board in the center and balance a pane of glass on it, seems
to be sufficient.  I also have a Stouffer step gauge to ensure I'm
exposing it for the right time.

> It takes about 6-8 minutes to expose this way.

My setup is 5.5 minutes.

> I understand you use the HCl+H2O2+Cu method to etch your boardds.  I
> use the same although I've been meaning to try and find some way to
> circulate the etchant across the board to speed etching and reduce
> undercut.

I got a kit with the tank, heater, air bubbler, and board holder all
pre-gathered.  The air bubbler keeps the solution moving.
http://www.delorie.com/pcb/lab/img_0213.jpg