Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uwm.edu!psuvax1!psuvm!jtw106
From: JTW106@PSUVM.BITNET (Jeff Wolfe)
Newsgroups: sci.electronics
Subject: Re: PCB making ?
Message-ID: <89341.162802JTW106@PSUVM.BITNET>
Date: 7 Dec 89 21:28:01 GMT
References: <2652@servax0.essex.ac.uk>
Organization: Penn State University
Lines: 43


In article <2652@servax0.essex.ac.uk>, zotog@SunLab14.essex.ac.uk         (Zotos
G) says:
>I'm new in this news group so forgive me if this has been asked before.
>I recently came to a point where I have to produce a good PCB.
>The easy method of drawing the tracks and the pads with a pen is not very good
>in compicated or/and fast circuits so I'm after a better but easy method of
>doing it.  Some one helped me by given me a book called "PCB made easy" but
>fails to give details of what chemicals and sort of things there exist in the
>market (in U.K.).
>
>The usual photographic method of transfering the layout to a film is very
>undesireable by me as I'm sort of dark-room and equipment.
>Has any one a good solution for my problem?
>
>Is it posible to photocopy the piece of paper with the track layout on a
>clear plastic film used on overhead projectors and use this as the film
>plased on the premade positive photoresist PCB and then to expose that
>in UV light ?

In my old High School, we used A software program for the PC (the name escapes
me at the momnet) that did basic things like Pads and traces, and advanced
stuff like autorouting. it even had a module that contained pinouts and specs
on about 700 chips or so. The pacakge ran in 512K on an XT, so I assume it
would run on an AT or a '386 without any mods.

Our output was a laser printed photo positive ( laser transparency ) which was
then 'burned' onto a silk screen. From there, we screened our PCBs and etched
them with Radio Shack etchant (we found that FFG textile ink worked held up
incredibly well in the acid)  Towards the end of the year, we experimented with
photo etching, but I do not know the exact processes behind it.

 I do know they used 2 Halogen streetlight bulbs for the light source, and some
type of photo-emultion that hardend under the halogen.



-------
                                                     Jeff Wolfe
  JTW106@psuvm.psu.edu                               114 Lake St.
  JTW106@psuvm.BITNET                                Dalton, PA. 18414

"A Computer's efficiency decreases as the urgency of retrieval increases"