kicad-developers team mailing list archive

[Vesa Solonen <vsolonen@...>]

On Fri, 26 Jun 2009, Lorenzo wrote:

> Said that, I found that most laser toner today are not opaque enough and paper transport isn't
> exactly linear in printers (traction is 'wavvy'). I won't recommend doing <25 mil work on home
> printers :P

Going a bit OT here, but anyway... For one layer UV-mask one should use 
full green from inkjet (cyan and yellow). Some experimentation for ink 
brand may be needed (try searching web first ;). I've seen 5 mils stuff 
done that way. Stuff that is opaque to UV is not necessarily opaque to VIS 
range.

For toner transfer the largest error comes from paper shrinkage during 
hot lamination step. That may be about half to one percent or so. Drying 
the peper before printing is of help as is low work area humidity. If wave 
amplitude is low enough and has not a cumulative efect, it's possible to 
stay in tolerances I think ;P. The old LaserJet 4000 TN does fine for 
TSSOP and, while not exactly home printer is cheap enough :). Newer colour 
HP at ¤JOB is more than good enough, 6 mils works too. It might be priced 
around 2 k¤ or so though. Proper temperature control for the transfer step 
is also a must, as is enough pressure and cooling. Old GBC four roll (hot 
+ cold rolls) laminators are great, but home made one is good enough most 
of the time. While shopping, try to find one with magical L-405 (hyphen 
may be elsewhere too) on it. Various brands with those numbers have a good 
design and are cheap. Pic of the guts here:

http://thomaspfeifer.net/laminator_temperatur_regelung.htm

One has to make temperature control for it and PD-controller with P(D/W)M 
power stage is easily made around a dual opamp. Oh, I should probably put 
that on the Wiki...

-Vesa