IBM 1620

Chuck Guzis cclist at
Sun Aug 30 17:09:56 CDT 2015

On 08/30/2015 02:00 PM, Jon Elson wrote:

> I hacked a fiber optic light pen onto a Calcomp plotter and made some
>  artwork directly onto film, and then in 1996 I built a laser
> photoplotter that cranks out 1000x1000 DPI images on red-sensitive
> film at 0.6 inches/minute.  It can do up to 20 x 24" films, but I've
> never gone over about one foot square.  The trick is, it has to be
> VERY accurate to line up with existing PC boards.  I mostly use it to
> make solder paste stencils, now, but originally made it for PC board
> master artwork.

That's pretty impressive, Jon.

I do remember the headaches with registration of early multi-layer PCBs. 
  Lots of rejects.


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