Originally Posted by
awerby
Hopefully you meant to say your set screws are staying in. Loose screws on a coupler could certainly cause the problems evident in your photos. Try running the pattern again, and see if it works better now. Just because it works when you're cutting air, it may not work when confronted with the resistance of plywood. If your program is trying to cut the plywood in small increments, then it would make duplicate cuts at progressively lower Z levels; they are supposed to stay in the same place, though.