Thanks Dean,

I ran a couple of jobs yesterday: one was some text in plywood for a sign, which was long but ran fine. The other was a first go in aluminium doing some roughing 3D work (I'm using Vectric 2 and 3D for my toolpaths).

The aluminium didn't do too well and I'm pretty sure I'm being a plank with regards feeds and speeds. Material is 6082 as per previous posts and I was running a Carbide 2Flute End Mill @ 12000rpm and 1200mm/min with 2mm DOC and 30% stepover (maybe a bit aggressive on the DOC?) and was blowing air. Anyway the machine seemed to hold up well i.e. nothing broke but was grumbling a lot so I hit Feedhold and saw that the edges in the pocket were clean, but it was obvious the cutter was trying to erode its way through rather than cut as there was a good "weld" of aluminium on the cutter and a "lip" around the edge of the pocket.

My guess is my feed rate is too low (possibly rpm to high) and I'm re-cutting chips?

What was cut didn't have visible chatter marks on the walls of the pocket, so I'm tentatively confident the rigidity is OK (2 ballscrews does indeed help :) ).

Will have a play later with a less aggressive DOC and high feed rate, but if anyone has their own feeds/speeds I can try then it may save me some time in trial and error.

Chris