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

[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.