Well, I finally got the diffuser cap assembly home from the printer. Washed off the alkali solution, dried if off and went for a test fit on the flashlight head.
POW! Just a tad too small and wouldn't fit! No! Where did I go wrong? I had measured until the cows came home and compensated for shrinkage of the ABS. Come on!
Then it occurred to me to heat the parts up in hopes of gaining that extra millimeter that might allow me to slip the parts onto the flashlight. So after about 5 to 10 minutes in very hot water I tried again.
I say success-'ish' as while the parts fit after being heated, the little snaps I had engineered to hold the two parts together were as fragile as old bird bones. Unfortunately since I printed the half of the cap that held the clips, with it's long axis vertical, the clips were printed such that the ABS was extruded across the clip's width. It was as though they were perforated and broke right off, with the slightest of pressure.
I was going to stamp this with 'back to the drawing board' but frankly the cap fits so tight, that it should be relatively toddler resistant and hold the lens material just fine.
Speaking of lens material, I built the cap to accept three circles of plastic from a plastic Chinese soup container, sandwiched together. Cheap, but I had it laying around and wouldn't have to source something. I might get around to posting a pic of the cap with the lens installed. Not tonight, though. I'm sick with a cold and just want to call it a day.
What I would do different next time.
- The clips were too small. I think I would have fewer of them around the bezel (say, 4 instead of 6) and make each one a bit bigger/more robust.
- More importantly, I would build the cap and the clips separately, such that after being printed the clips would be glued to their host. This would allow me to orient the clips in the printer such that the print striation goes along the length of the clip, hopefully making it much less likely to just snap off.