Homebrew PCBs

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Malcolm


 
I don't suffer from insanity I enjoy it!
Mene, mene, tekel, upharsin
The writing is on the wall.


________________________________
 From: DJ Delorie <dj@...>
To: Homebrew_PCBs@yahoogroups.com 
Sent: Sunday, November 25, 2012 10:22 PM
Subject: Re: [Homebrew_PCBs] Need comparing methods for smaller IC's (0.35mm pads and 0.15mm interpads area)
 

  

I have no problem doing 0.5mm pitch ICs with UV films and an Epson R280
(2880 dpi) inkjet printer, although I use the jetstar films and custom
printing software for the densest artwork.

0.5mm is 20 mil (12px for 600 dpi), and the pads are 13mil with 7mil
gap.  You might be able to do get away with 8/4 pixels (8 pixel lines, 4
pixel spaces) on a 600 dpi laser printer, if you've practiced enough :)

The DPI of the laser printer isn't as important as how accurately it can
place the toner without the toner being "fuzzy" around the edges.  Most
of the time, the copper edges aren't straight - they're "lumpy" as the
toner is sort of "thrown" at the paper and doesn't always land exactly
where you expect it.  The "lumpyness" depends on your technique,
printer, paper, etc.

For reference, though, here's 6/6 done with toner:
http://www.delorie.com/pcb/lab/66-0.jpg
Compared to 6/6 done with UV film:
http://www.delorie.com/pcb/lab/6mil-front.jpg

Here's a sample 0.5mm pitch part done with UV films:
http://www.delorie.com/pcb/lab/6mil-0.5mm.jpg

 

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