Test pattern for tuning UV
2014-04-14 by James
I rebuilt my UV box with 9 rows of 12 leds covering an A4 area, I had to use a diffuser in the end otherwise because of the fairly wide spacing the led mounting was too critical to get a good even spread (even with the leds 15cm away from the artwork). Anyway, I wanted to dial in the numbers a bit particularly because of the diffuser I was concerned that the resolution wouldn't be there (turns out, nothing to worry about, 8/8 seems just fine, I'm never going to want less than that). I couldn't find a simple small test pattern in a usable (gerber) format, so I made my own, perhaps somebody might find it useful also one day. Lines from 8 to 18mil, separations from 8 to 16mil, holes 0.8mm and 1.1mm with 0.2mm, 0.35mm and 0.5mm rings, 1206,0806,0603 and 0402 pads, and a minimelf for no particular reason. All repeated 5 times for a stepped exposure to home in on the right time (which turned out to be around 3m30s, but there is a massive amount of leeway, probably a minute either side is usable). Anyway, here it is on github, gerber and pdf https://github.com/sleemanj/pcb-test-pattern you can use the Download Zip button on the right side of the page if you just want the files and not mess with git.