Homebrew PCBs

Quoth Mike at 2008-05-05 07:38...

> Hint: make several copies of the design or of other PCB layouts, 
> print them out using the inkjet printer, cut the inkjet PCB layouts 
> out and glue them to another piece of paper.  Have the laser copier 
> transfer all the layouts to the toner transfer paper.  Cut out the 
> PCB layout from the TT paper and make the board.  This approach 
> reduces the wasted TT paper.

Good tip, especially for those of us on a tight-ish budget.

The same hint also applies to the very pricey 'Laserstar' film (looks 
like tracing paper with a big price tag) that I use.  Don't use just one 
sheet per board unless 1) you are actually producing A4 sized boards or 
b) you are very rich.

I create my layouts in Eagle.  When I create the PostScript file in the 
CAM processor, I keep changing the X/Y offsets of each design so that I 
can fill a whole sheet of paper.  As my printer is actually a PCL type 
rather than PostScript, I convert PostScript to PDF and print the 
designs using Acrobat Reader, feeding the same sheet of paper back in 
each time.  To make sure that I have calculated the correct offsets, I 
first perform this procedure using a sheet of plain copier paper.  Once 
I am satisfied that I have no designs overlapping or too close together, 
I then print all the PDFs again onto the Laserstar film.

Note - after about the third pass through the printer, the Laserstar 
film starts to curl a little; I have found that gently rolling it up in 
the opposite direction to the curl seems to get things straight again.

The one thing that would make my process easier is if I had a tool that 
could merge my PostScript or PDF files.  Tried it using an art package 
(the Gimp), without success.  I also tried a bit of raw PostScript 
programming a year or so back, but that just gave me a headache ;-)

Cheers

M


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Matthew Smith
Smiffytech - Technology Consulting & Web Application Development
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