Think and tinker has step by step directions for an excellent
exposure setup. Not expensive either.
Calibration is easy inexpensive, and also described.
Ballendo
--- In
Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...>
wrote:
>
> Les, I agree that that is the ultimate method of making PCBs
> but...you forgot to mention follwing problems:
> 1. You must have a good UV exposure box-- let's not start another
> dicussioon today what that means. It is not a trivial issue
although
> for some it might be. The issue here is the resolution because I
have
> seen a keproo UV box for $500 failing to give a good resolution on
> TSOP- it was all FUXXY! On quality PCB material, too.I will only
> state that depending what you are building, the uv light may or
may
> not work for some or many applications. And let's not expose to
sun
> light for a while either :)
>
> 2. Once you have the box you need to calibrate the bloody box and
> depending what light it uses the timing might be all over the map,
> depending on the preheated condition of the lamp. Depending on
what
> you are using. Calibration alone is not for weak people either.
>
> 3. PCB material: buy ready made (expensive), use negative or
positive
> (explain it to a nenwcomer), apply film, make your own secret
> emulsion, dry, spray, develop (how long, oops, lets strip it and
do
> it again, and again... what teh hell is that today...). Then
finally
> comes etching which is trivial..
>
> Now, I am waiting for someone to say that he is happy with scratch
> and etch or printing directly on copper!
>
> Overall, I know that UV is best, and I know it works fine because
I
> have the whole process prepared when... when I get tired of TT-ing
> PCBs. So far I don't foresee it. Stick a secret Staples paper in
the
> laser printer, hit 'print' and pull the paper out of the printer.
> etch it and remove the paper. Then you drill. No adjustment
process,
> no secret uv boxes. Mike
>