Now that most of my issues with the x carve are resolved beyond some fine tuning, I thought I would start trying to do a real project. I didn’t want to jump in with a complex cut in 1/8" aluminum plate, so I started with machinable wax. I had some in 75mmx150mmx3.5mm plates. One issue right off the bat is the thickness varies a lot in this material, in the piece I started with it went from about 2.9 to 3.5. You have to be careful when you zero the bit to the top of the surface that you are not on one of the thin parts.
I bumped up the feed rates and cutting thickness from aluminum, after all the point is to test out parts without waiting all the time it would take to do the cut in aluminum. I did 400 mm/sec with .5mm cut thickness. That turned out to be conservative, I probably could have gone a lot farther. The material machines beautifully. There is no grain or anything, it cuts perfectly without cracking or chipping. The chips are kind of like snow, and are mostly blown out by the air current coming from the air cooled spindle. It looks like you can have a wall thickness of only .1 mm and it will not chip out. It is delicate so if you make any fine details, you have to be carful not to damage them with your hands. I didn’t use tabs, but instead tried to leave about .2 mm of material at the bottom like an onion skin. This worked OK, but was difficult to dial in due to the variation in thickness.
Anyway here is the finished construct, a pair of linked elliptical gears that will turn against each other. This is based on a similar part I saw on thingiverse for 3D printing. I made a new version from first principals, using autocad and cambam. Each gear is about 60mm on the long axis.
