[sci.electronics] Printed Circuit Boards

bauer@procase.UUCP (Jerry Bauer) (01/26/89)

The plot thickens...

I used to make a mask (for each side) at 2x, have it photographically
reduced and copied to film (at a local printshop) and do the
photoresist/expose/rinse/etch routine. 

I made the masks using the Bishop Graphics (or whomever) pads, edge
connectors, etc. and tape.

The first IDEA occurred when I decided to write a p.c.  board drafting
program for my Apple //e.  I figured it would be easier to draw it there
than with the tape and stuff, and run it off on my plotter.  From there,
it would be back to the copy-to-film/photoresist/expose/rinse/etch routine. 

The second IDEA (and this is where it is today) was to make an adapter
for a resist pen to fit in the plotter and draw directly to the board. 
This works great - even for two-sided boards (accurate registration is
important, of course).  The processing consists of draw/plot/etch.

Well, that's it.  The computer is an Apple //e, the plotter is a
Mannesman-Tally PIXY-3.  The code is home-grown. 

So, does anybody have a quick, cheap way to do plated-through holes?



-- 
JRBauer (Jerry) ...!tolerant!procase!bauer
                ...!hpda!procase!bauer
                ...!cae780!procase!bauer

rlf@mtgzy.att.com (r.l.fletcher) (01/27/89)

In article <4115a910.14dd6@c>, bauer@procase.UUCP (Jerry Bauer) writes:
> 
> The second IDEA (and this is where it is today) was to make an adapter
> for a resist pen to fit in the plotter and draw directly to the board. 

This is the second time I've seen references to "resist pens" in this
group. In my experience special resist pens are just permanent ink
magic markers. I stopped buying special pens years ago when I discovered
that five and dime magic markers worked just fine.
Is there something special in the resist pens?

					
					Ron Fletcher
					AT&T Bell Laboratories
					Middletown NJ
					att!mtuxo!mtgzy!rlf

gordonl@microsoft.UUCP (Gordon Letwin) (01/27/89)

In article <4115a910.14dd6@c>, bauer@procase.UUCP (Jerry Bauer) writes:
> 
> The first IDEA occurred when I decided to write a p.c.  board drafting
> program for my Apple //e.  I figured it would be easier to draw it there
> than with the tape and stuff, and run it off on my plotter.  

If you have a 300 DPI laser printer you can do a good job direct to it.
My boards are sufficienly simple that I don't need auto layout, I just
need the drafting services of a simple program to generate the patterns
on an HP LaserJet II

> So, does anybody have a quick, cheap way to do plated-through holes?

Sintek electronics sells a hand operated gizmo that takes a "belt" of
little plated pieces of metal.  When you operate it it "injects" a
metal rod into a PCB hole.  Bottom line is that it's a fast and easy
way to do Z-wires.  The studs supposedly hold themselves in by mechanical
pressure, so although they have to be soldered it should be a simple
and reliable operation.  Not as nice as plate through, especially since
plate through makes component soldering so much more reliable, but
it sounds a step up from z-wires.  I ordered one of these, If anyone is 
interested, email and I'll report on it's value after it arrives.

Naturally, I'm also very interested in real plated through holes.  Does
anyone have any pointers or advice on what it might cost to have this
done, in small batches, presumably by a PCB service company?

	Gordon Letwin

kevinro@microsoft.UUCP (Kevin Ross) (01/28/89)

I have found that a page printed by an HP laserjet can be transfered 
directly too a copper clad board using a household iron set at a very
high temperature. This worked VERY well, even for fine detail work. 
I was routing traces between DIP pins, and they worked great. Just for
kicks, I transfered part of a printed page to a board, and etched it.

As an experiment, I tried using several different plain paper copiers
to do the same trick. I found that the toner in the copiers did not 
transfer nearly as well as the others. I imagine that copiers are all
slightly different. I tried this trick using a Toshiba and a Canon copier,
with very poor results.