Cutting wood

[outsider787]

I just started using a CNC, and decided to cut some shapes into a piece of wood. (pocketing).

The outside edge of the pocket ended up being very rough, with lots of splinters and loose fibers.

I also tried doing some pocketing in MDF, and similar results. The outside edge is not clean (like when cutting metal or plastic), but rough and frayed.

What am I doing wrong? Feed or spindle speeds too fast or too slow?
I was using a regular metal 3/8 endmill at about 3000rpm.

[jm82792]

Try slowing your feedrate down and increasing spindle RPMs. End-mills will leave a poor finish if you go too fast. Make sure your cutting depth isn't too much. I'm rather new to this but that should help you get started.

[Stewey]

Maybe the endmill or cutter is blunt?
Maybe the feed speed it too fast and the rpm too slow?

Since timber has a grain, you will tend to get varying edge finished depending on whether you go across or with the grain, and depending on whether you rout against the grain (conventional) or with the grain (climb cutting).

[Stewey]

Maybe the endmill or cutter is blunt?
Maybe the feed speed it too fast and the rpm too slow?

Since timber has a grain, you will tend to get varying edge finishes, depending on whether you go across or with the grain, and depending on whether you rout against the grain (conventional) or with the grain (climb cutting).

[cjsamples]

Could it be the feed direction of the cutter? Some materials need to be fed in a certain direction.

[outsider787]

I bought a few straight flute routing bits (for a router) and the results in wood are considerably nicer. pretty much eliminated the problem.

MDF is still problematic. Edges still fray like crazy. Maybe need a down-cut end mill... or faster spindle speed (which won't happen anytime soon)