Wow! This sh1t gets expensive fast ;)

This sorry saga relates to the part shown in the OP.

Waited a week for the cutters to arrive, first 5mm carbide bit the dust in 30 seconds! The speed calculated at 12000rpm and using my lookup table i set 14500rpm as my speeds are off. The cut started and as soon as the cutter ramped in about 0.5mm of the 2.5mm set the motor bogged down like it was totally powerless and ping went £10 :(

So, back indoors, reprogrammed for about 20,000+ rpm and started again on my reserve tool, all started ok, 1st pass was flinging sizeable chips across the room, ramps down for second pass and even though i set 0.4mm holding tabs in various places, the first part broke free and fell out thus ruining that bit. Thinking the cut was too heavy i backed off the feed a bit in Mach3 and let it go, 75% of the last roughing pass and the part breaks free and takes the cutter to the bin with it. It's irrelevant but thats £25 of bits in 15 minutes, plus another sheet of 5mm Alu in the bin. :( :( Talk about pissed off!

Right, observations...

1 - Is this job actually possible?
2 - is there any point at all at running less than 100% RPM - these spindles seem to have zero power.
3 - It seems to be cutting 0.2mm below the set height - I need to tweak the Z height routine a bit, set the plate thickness a bit off to lift the tool 0.2mm
4 - How thick should holding tabs be - I set 0.4mm but clearly not enough.
5 - I set 2.5mm DOC for the roughing on a 5mm bit, go less, 1mm??

Exceedingly vexed at the moment :(