Actually it wasnt, but that was my fault. I made a big mistake. Or 4.
(a little knowledge is a dangerous thing)
I was helping a school get their 70 watt laser setup. We engraved a couple of little trinkets. Then we did a test grid for scoring/cutting and one for engraving. We engraved and cut a gnome image….but it didnt cut out (we used settings from the test grid. So we designed a ruler and tried to engrave & cut. But they wouldnt cut out. We upped the power for cutting from 50% to 60% to 70%. No change on the cut. Engrave looked fine.
Mistake number 1 —- “well, we didnt focus the mirrors”
Mistake number 2 —- “the manual and this one video says the laser has to hit the center of mirror 1
Mistake number 3 —- we didnt check the existing alignment with tape/pulse method before attempting to re-align
(put a piece of painters tape over the circle frame in front of mirror, send a laser pulse to see where dot is)
Mistake number 4 —- i vaguely remember the minimum power setting was lower than max, but had read that was alright for when the laser has to slow down at corners…maybe this was the only problem. That setting was too low.
Laser doesnt hit center of mirror 1, so I fiddle with the mirror a little, then the tube a little, I dont want to mess with the tube too much. Colleague finds other videos/sites that say “beam does NOT have to hit center of mirror 1”
Move on.
Mirror 1 to 2. Since I fiddled with mirror 1 already, beam is not parallel to axis. So I need to work on mirror 1 to get the near and far dots to line up (near is when mirrors are close to each other (top/left) and far is away from each other (bottom/left)). Finally get it
Mirror 2 to 3. This beam has to be in the center of the mirror and near & far dots must line up. fiddle, fiddle, shift, adjust….aligned but not hitting center. I need to move the mirror frame – but move it parallel. Well that aint gonna happen, it wobbles so much. After much back & forth I think it is good.
Mirror 3 sends beam down the tube to focusing lens
Put the nosecone all the way down on wood, send a pulse. Should get a dot, not a half moon, not a crescent. Also, raise the tube up an inch or two, then again, dots should be on top of each other. Crescent. We are hitting the tube. Fiddle, fiddle, adjust…back & forth back & forth. Not there.
Sleep on it.
Back up and make sure we are truly aligned from Mirror 1 to 2 to 3. Mirror 2 needs adjusted for alignment and moved to hit center. I take the nosecone of the focus tube to get a bigger are to see (also, mirror 3 has adjustment screws all the way lose). Put tape on the end, hit pulse…we are hitting the tube. Use adjustment screws to get “center”. Put the nosecone back and – a little off center (getting crescent). A little more adjustment and we are “good”
I think I finally got it
I hope I finally got it
Ran test grids again, got numbers (slightly different). Used new numbers and things cut out.
Lasered the gnome again, I think it looks better this time (and it cuts out)
(sorry, no pics)
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