Terry Mickelson wrote:
> Firstly, thanks to everyone who replied and a special thanks to those
> that also supplied URLs.
> I'm basically screwed. My toner transfer isn't working a hundred
> percent and several papers were tried along with times and temperatures
> in a press and each had their own peculiar problem. The number 1
> problem is board cleaning followed by toner line edges that "wobble".
> It'll work, eventually. (See "Three Foot Rule", below.)
> The UV lamp question was sort of answered but I still don't know
> whether to get a bulb or a tube...
As long as the ink on the film is tight against the resist, close
tubes are ok. The celophane plastic on dry film resist is about 0.4mil
thick, so undercutting due to light coming in at 45degrees still
doesn't affect an 8mil track much.
The effect of this undercutting light is that where edges end up
after etching is highly variable on the various degrees of exposure,
developing, and etching used.
With a collimated light source and decent film printout, you could
expose for 30secs or 5mins and still get tracks with little width
variation.
HID lamps need 2-3mins to warm up, and once switched off, won't
switch on again until after cooling for 5mins. Tubes are instant.
HID lamps are higher power in a small space, so they're more like
a point source and are much easier to use with a decent large
reflector. You can use one tube and a large reflector, but a
24" tube is only 20 watts. So: close tubes and consistant
timing to get good results, or a distant and focused HID globe
to get good consistent results with non critical timing.
I can also use films with the ink away from the copper (a film
printed without mirroring by mistake) and still get sharp traces.
Close tubes give very blurry traces.
My 125W HID box doesn't have enough power to do spray-on PRP
resist in 10-15mins, so i need to use the 4-tube fluoro box
for that. I haven't used prp for a while.