The replacement mirrors and lens arrived this morning, and I got them installed and working this afternoon. The laser is functional again, maybe even a little better than before. Let the artmaking resume!
I replaced mirror 2 (which might have been OK), mirror 3 (which was trashed), and the focus lens (which was destroyed). Did a full alignment on the optics, and a rough spot-check on the table leveling.
People have noticed that the laser seems weaker on the lower right and works best in the upper left region of the work area. It’s normal for there to be some small differential, because of the longer beam path to reach the lower right, but it was much worse than normal. I think it’s improved now. A cut that worked at speed 17 in the upper left required a speed of 13 in the lower right.
The new lens has a slightly different focus point than the old lens, for whatever reason. I have adjusted the autofocus probe to what seems to be the best focus point for the new lens. If you prefer to measure, you’ll find the new focus point is several millimeters longer than before. That is, the table is a bit lower with respect to the cutting head.
People have had trouble cutting half-inch plywood. I was able to cut a small square out of half-inch plywood today, in a single pass at speed 17 (or 13 in the lower right corner) at 100% power. There was some charring on the edge of the wood, but nothing that wouldn’t sand off. The only trick I used was to focus a bit down into the material, instead of at the surface. The Z axis setting I used was about where the autofocus probe touches the material, but that was just an educated guess. You’ll still need to experiment with settings and focus heights to find a configuration that works with your specific plywood.
I still think we can get better cutting of thick plywood (half-inch and maybe thicker) by getting a stronger air-assist compressor. I’ll look into that soon.
I hope to see you and your laser-cut art at YOUtopia!
For best results cutting plywood, cut solid core poplar plywood. Things like baltic birch (with more thinner plys) have more glue, which cuts much less well than wood.