Cutting POM/nylon/Delrin ?

I've tried different toolbits to cut some medium hardness POM. (kinda like delrin I think.)
I'm having problems with fringing instea dof cutting on the top edge of the cut making the swarf stick to the workpiece along the cut.
It happens with both standard and climb milling.

I've tried bits with multiple flutes, but have yet to get one with only 2 or 1 flute which I heard will be best.
Am I also right to think that a low helix bit is best (few degrees turn pr distance, almost vertical flutes) to allow cutting of this top unsupported part instead of folding the swarf up and out uncut?

Another thing is sharpness. Can I sharpen the sides of a endmill? If so, how?

Looking for any and all tips here as my results are shaggy!

Yeah, I figured I need a better toolbit.
4-flute with too low helix angle just pushes stuff up on the edge.
It works fairly well if I feed at 900mm/min though but on a homemade machine of MDF board that's kinda insane.

Here's a result from a 4-flute 4mm endmill:

can u run some coolant !
a good sharp high-positive carbide cutter is what u need, if u can't use coolant of some sort, there ain't much hope! -even grinding a piece of carbide, (single flute) as long as u "stone" the edges it should be fine.

try running the program again over what you already ran.
the deep cut may be clogging the flute when taking a small cut.
and as M4MazakUser said, coolant. try WD or some kind
of penetrate. just a little spray on the whole program should help.
Good luck !

The machine is made of MDF so coolant is not possible. It would soak into the parts making them swell.

The cut was programmed as a 1mm clearance roughcut using circular path, 2mm depth and 3mm stepover with a 4mm bit.
Then a zigzag finish was done to 0 tolerance, with 0.5mm stepover.

Turned out the 1mm clearance from rough also left a 1mm edge around the object too making the finish grip the sides when it reached the ends.
Seems like a bug in my app preventing me from using clearances on selected objects. Wierd.

kreature wrote:

The machine is made of MDF so coolant is not possible. It would soak into the parts making them swell.

i've used a paint brush before, that would still be plenty.

The cut was programmed as a 1mm clearance roughcut using circular path, 2mm depth and 3mm stepover with a 4mm bit.
Then a zigzag finish was done to 0 tolerance, with 0.5mm stepover.

i was thinking more like .005" (.12mm) to .01"(.25mm) final cut. the 4mm(.157") should cut that pretty good.
and as John said increase the feed and slow the rmp. you'll have to test different feeds/rpm.

Turned out the 1mm clearance from rough also left a 1mm edge around the object too making the finish grip the sides when it reached the ends.
Seems like a bug in my app preventing me from using clearances on selected objects. Wierd.

a flute(s) (1 or 300) will "grab" the thin edge of the material as i goes around. so you'll need
to leave more along the edge. see how it "grabbed" the two thinner sides.

No, the rough cut didn't rough out to the edges, thus it fubared the finish on the edge too.
The outer edges was not part of the design at all but a result of a bit small workpiece.

Due to how emc2 slows down when encountering slight angles, it is hard to keep up the velocity on the curves.
I am already running it close to peak velocity, but I can reduce rpm to about half.