Homebrew PCBs

Philip Pemberton wrote:
> 
>>I hope to make it cheap and easy enough for
>>anyone to make with mainly parts you could get
>>at places like Jaycar. (cheap and easy are
>>relative terms I know :D)
> 
> 
> The hard part is going to be finding the steppers, and focussing the laser 
> down enough to get a decent amount of resolution out of the film. I haven't 
> seen any laser pointers that can be focussed down below 1mm...
> 

Yes, cheap and easy are the two words I had in mind when pondering on 
the idea of a homebrewed photoplotter. The dedicated photoplotter film 
was a bit pricey from memory, but worse was the $1000 odd minimum order 
quantity for me (in Australia). I didn't shop around  and I cant 
remember who I called, may be it was Kodak ?

http://www.kodak.com/eknec/PageQuerier.jhtml?pq-path=2608/2610/4131&pq-locale=en_US




> Where do you get that stuff from? I've never seen it for sale anywhere...
> How do you develop it anyway (in fact, do you need to develop it at all)? I 
> did a bit of B&W photography a while ago, so I'm thinking of this from a "how 
> is photoplotter film different to B&W film/paper emulsion" perspective...

I believe the film is processed just as B&W film. I don't know what the 
difference is with B&W film and 'photoplotter' film besides the spectral 
sensitivity. Maybe B&W can work in a photoplotter, with appropriate 
laser.  It seems lasers other than red are very expensive so that may be 
their limitation.

The most accurate drive mechanism will be a stepper motor and a toothed 
belt drive combined with a linear optical encoder. Better than 20um 
resolution should be possible.