I am cutting Baltic Birch plywood, and I have been cutting BB for a long time. I have two machines, and one of them cuts just fine at 165/full, but the other one burns the back of the plywood and flares up quite a bit (small flames inside the GF).
Here are examples of the backs of the same material, the same file, but one was done this summer, and one was done last week. Same settings, same wood.
What could be the problem? It seems unsafe at this point with the amount of flames. Is my laser getting old or the fan system?