Burnt bit slotting MDF

[JAZZCNC]

I've since bought some straight flute bits from toolstation (coming tomorrow) & some 2 flute carbide and 2 flute HSS bits which will take a while to arrive.

Don't waste money on HSS if cutting MDF because they wear out far too quickly.

Am I right in thinking that of the 3 different cutters I've ordered, the straight flutes would be good for this job?

They'll work but you'd be better with spriral up cut because they eject chips better. You'll need good vacuum with straight flute.

How would I know if the machine (chinese 6040) is up to the task? Would the motors stall if it's too fast? Cutter break? Or worse?

If not up too it then could and probably will do both.? The spindle will Bog down and stop cutting causing the steppers to stall, hopefully before cutter snaps. If they don't stall then the cutter will most likely snap.

Shouldn't damage anything on machine really as they won't have power enough to break anything, worst case you'll knock spindle out of tram.

Also, for slotting, the toolpath is plunging at an angle like a ramp as it gets deeper towards the DOC. This plunge feed setting by default is around 300mm/min.. should this be upped a lot? This seems slow for the shallow angle it's doing until it gets to depth.

Yes it's very slow and if shallow angle with multiple passes to DOC then you should be able to cut just little slower than cutting feed.