Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet

[JOGARA]

Cut my product's case rear end.

Not perfect. Some work to do on the CAM but in terms of output it is great.



Really do need a chamfer bit...

[JOGARA]

So I started playing with the 6mm that was included. Worked well at first.
Was getting some nice test cuts with it so decided to give it ago milling out my case.



Working well for a good 45 mins. I had the feed rate at 200% as my stock settings was making quite a fine chip.
Having it at 200% made a much nicer chip that flew straight off.

It got to about 2/3s the way down the 15mm bit of aluminium and the sound frequency changed.
Went to check it out and I went to pause it but suddenly the bit started to get hot so the chips welded onto the bit.

Doh

Obviously can't go that fast when the ali has warmed up and you are doing 2mm cuts.

Was only air cooling though. I found water kept clogging up the chips and well I don't have any proper coolant system or liquid...

[Zeeflyboy]

If you are getting fine chips or dust, rather than upping your feed consider dropping your rpm to keep the material removal rate at a reasonable level... it will help control the heat production and reduce issues with tool deflection/chatter when compared to ramping up the feed rate. You need quite a rigid machine to get away with the high feed rates associated with faster rpm.

Bear in mind of course that these spindles don't really like much below 12k rpm for sustained periods. Coolant allows you to sustain a higher removal rate than dry cutting of course, but it isn't absolutely vital for good results it just makes dialing in those feeds/speeds a bit more critical. Chips do look better in that pic above.

This is where single flute give an advantage as you are effectively running at half the rpm vs a comparable 2 flute bit.