gEDA-user: PCB Paneling toner transfer test

[John Griessen <john_g@xxxxxxxxxx>]

Just made a toner transfer to copper clad and it was a partial success.  Next I 
need to check dimension accuracy with a different test pattern and panelization 
and commit to using one of the coarser line sizes like 8 mils or 10 mils and 
maybe later refine this further with photo paper from Staples and maybe a finer 
laser printer.   Each change of laser printer gives different toner and a new 
learning curve though!

To make the layout patterns for my test I used DJ's   pcb --action-script 
panelit suggestion, where file named "panelit" has pcb commands in it with no 
variables, just in line code to step and repeat layouts.  My panel has nine.

http://shop.cottagematic.com/photos/first-etch-700x1150milsx9.jpg

The photo has some arrows and comments about trouble spots with the Laserjet 4Si 
artifacts, toner holes, toner missing and what not.   lj4ps had
problem with the smallest 4 mil set of lines I gave it, so maybe I need a better 
printer to get better fine lined output.  I definitely need better to get less 
holes in the toner.  It seems like I can get decent 6 mil lines with some yield 
losses one 2 square inch boards due to toner holes. 3 x 5 inch boards would need 
bigger traces or low yield as this stands.  My test has them all separated by 
the same space as traces are thick so I can see if shrink or bloat are going to 
be wanted to get accurate sizes after etching.  I'll use more space between for 
a circuit board.

The transferring from photo paper to copper clad was done with a laminator 
roller machine that has a temperature controller, a push in roller, and a pull 
out roller and 2 inch wide top and bottom platen heaters between.  I had it 
"good and hot" -- meaning I didn't put a thermometer to it yet...  I wrapped a 
half inch of the photo printing paper over the edge of my board material, (1/0 
FR-1 1.6mm thick), to avoid buckling as it and the fat FR-1 slid between the 
heaters and as the pull out roller grabbed them.  The pull out roller after the 
heater seems to be the one with the higher pressure squeezing the layers together.

I ran a test with just a small pattern of toner on a transfer sheet first.  Ran 
it in and through and it didn't stick.  Cranked up temp. Repeated and it stuck 
more. Realized preheating the board was a good thing, and wrapped a second board 
in regular paper and ran through twice fast, then put transfer sheet with nine 
layouts on and ran it in and it stuck first pass.  Smelled smoky in my little 
office after that...

The FR-1 was too hot to handle and still hot when I got to the sink, so I cooled 
the board side first with water then dunked it paper up.  The paper separated 
from the edges first and was loose with a light touch after 30 -- 40 seconds.  I 
had thought that was going to be harder.  What's left is a kind of paper coating 
like glue.

Next, I put it in a pyrex dish with soapy water and swirled a natural bristle 
paint brush against it some, then scrubbed one end with powdered cleaner, (Bar 
Keeper's Friend), until some of my toner image details were coming off, whoops! 
 Under a magnifier, that glue was hanging in there enough to cause etch 
resisting, so I got a sponge and more powdered cleaner and gave it an overall 
light scrub  -- that seemed to work well.  There was still some grey on some of 
the toner that I could not get to come off with more time in warm soapy water 
and paint brush action.  You can see it in the scanner photo linked above.

John G

Peroxide HCl etching next





_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user