Homebrew PCBs

DJ great results reporting.  In the part

 

Theory: The unevenness of the copper due to the underlying FR4 was causing
uneven pressure and missed spots.

Test: The PCB was sanded to 2000 grit, resulting in a mirror-like surface.

Results: It's hard to see in the photos as the copper was reflects enough
light in the scanner that it appears dark, but there was very poor adhesion
of the toner! This was a very unexpected result - the toner needs a
mechanical bond to transfer. Scuff it!

 

Can you explain what you mean by scuff?  Are you referring to using the
green Scotch Brite pads?

 

Jeff

 

  _____  

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of DJ Delorie
Sent: Sunday, November 20, 2011 3:34 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Testing TT with Transparencies

 

  


To learn about transparencies, temperatures, and techniques for Toner
Transfer, I took the time to run a series of tests with my hacked
laminator:

http://www.delorie.com/pcb/transparencies/

24 different transfers, with comparisons and the original (big) scans
of the results.

Summary (if you don't want to look at all the pictures :)

* no matter how hot the laminator is, you need multiple passes

* there's a fine line between "stuck" and "squished"

* cleaning the board and keeping dust off everything is still critical
(sigh)

* preheat the pcb

* don't put paper between the film and the rollers after the first
pass. You can probably make do without it for the first pass too,
but it helps keep the film in place. Tape would probably do if you
need to accurately align the film.

* you *can* apply a second layer of toner if you need to, if you can
align it sufficiently with the first.

* a mechanical bond is required; if the copper is too shiny the toner
won't stick.





[Non-text portions of this message have been removed]