Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: "lcdpublishing" <lcdpublishing@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, May 20, 2007 1:31 PM
Subject: [Homebrew_PCBs] Photo-resist etching questions....


> Hi guys,
>
> I have almost given up on direct ink-jet resist and on "plotting"
> with Staedtler pens using the CNC machine, and I am about to abandon
> toner transfer. Only problem with toner transfer is the "scaling"
> issues either through the printer or from the paper not being stable
> which causes problem with CNC drilling.
>
> Anyway, I ordered up some negative type resist chemical, the
> developer, a lamp, and an exposure frame. I am not expecting this
> to go "perfectly" either, but am hoping to have a bit less
> frustration in other areas.
>
> I am thinking the best accuracy I can get when printing is to use an
> ink jet printer (I have Epson R220 and Epson CX6600). I have a PDF
> editor program that allows me to edit trace colors and back ground
> colors so that I can make negatives so that shouldn't be a problem.
>
> The first "problem" I suspect I will run into is getting enough
> density on the transparency to make sure the "black" areas are dense
> enough to block out the UV exposure lamp where needed. Has anyone
> run into this issue and how do you deal with it?
>
> Any other pointers would be greatly appreciated as well as this is
> my first time for "photo-processing".

It depends on the printer and transparency material. I get very good results
with an HP 5940 (quite cheap) and JetStar Premium film from Mega
Electronics. That's the only film I've tried that works properly with that
printer, it's specially made for PCB work. You will probably find that a
positive process is easier.

Leon