I made prints on 76ยต (3mil) polyester drawing paper, I bought them 20 years ago to make PCB, using a pen plotter and UV exposure. This paper is very stable with temperature and moist.
Placing one sheet on top of the other (not face to face)give a perfect alignment.
It is not possible to get a good alignment when putting sheet face to face ..
Some via are misaligned by up to 30 mil.
There is only one explanation, the optic inside the printer is not perfect.
Has anyone of you already faced this problem ?
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double sided PCB, accuracy - 2nd part
2008-07-05 by Michel Baguet