I’ve tried twice now to carve this aluminum and both times it has cut super rough. The first time I’m pretty sure I damaged the bit when I tried probing the surface of the metal and jammed the bit into the metal…whoops. This second time was smoother with a new bit, but still quite rough.
Feed speed: 100 in/min
Bit: 1/8th Fishtail Upcut (Teal from the starter bits)
The 100 in/min seems fast but I saw it recommended here on the forums that going fast with a shallow DoC to keep the chip load higher, about 0.003. The machine cuts wood, mdf and acrylic very well.
The chowdered aluminum (I tried with two bits, that’s why it has cuts in different directions.)
I don’t work aluminum, but that seems to have the hallmarks of an off-axis mill, because you’re getting hills/valleys. Have you confirmed that your tram is true (as Haldor mentioned) and that your all squared up? Are you squaring the surface with a flat-bottom bit before carving (or is that what you’re trying to do here?)
I thought so too, but I’ve checked everything I can think to. Though I haven’t flattened my waste board yet as my machine doesn’t have a permanent home yet. Would that be able to cause this kind of result though? Wouldn’t the result just be out of square?
Since making this post I tried doing a run at 0.005 DOC and 50ipm and it was nearly as bad.
If your Z axis have any flex in tilt or elevation (even minute) the bit will end up being tilted and wanting to dig in. This isnt a good combination. A poor bit for the job may also compound to this.
I do a bit of aluminium (but not on Xcarve) and for a 1/8" 2F bit on a unknown system I would start with:
35ipm @ 17k RPM
DoC 0.004" (Increase this value if previous work out okay)
My first DIY CNC I would have no problem going 0.004" at 20IPM per tooth but 0.008" would cause issues do to lack of rigidity on my Z axis. I have the same machine today but its upgraded with stiffer gantry, mass damping and a very stiff Z-slider and I can now go way beyond my initial capacity.