[Devastator]

I'm having trouble cutting clean slots in cardboard tubing on my DIY CNC without the endmill causing ragged edges or fuzzing at the edges of the cuts. Any suggestions on tooling and feedrates/rpm invited.

[Dylwad]

How thick is the cardboard, how big are the slots, and whats your max rpm?

Pcb routers come to mind.

[Devastator]

How thick is the cardboard, how big are the slots, and whats your max rpm?

Pcb routers come to mind.

Tubing is .050" wall, slots are .1875" wide. Max RPM is 25,000. Thanks!

[neilw20]

Use smaller cutter and make a pass along the middle, then a cleanup pass climb milling to finish. Cutter must be really sharp, and watch how quick it wears.
To make it last longer, on the finish pass use Z ramping down or up move to even the wear on the cutter. Down is probably better.
Keep the speed down, and feed up bit so there is a positive cutting action.
If it is not climb milling it will just push the stuff out of the way, hence the first pass to rough out the slot.

[Devastator]

Use smaller cutter and make a pass along the middle, then a cleanup pass climb milling to finish. Cutter must be really sharp, and watch how quick it wears.
To make it last longer, on the finish pass use Z ramping down or up move to even the wear on the cutter. Down is probably better.
Keep the speed down, and feed up bit so there is a positive cutting action.
If it is not climb milling it will just push the stuff out of the way, hence the first pass to rough out the slot.

Thanks for such a detailed response. I'm getting ready to order tooling. Do you suggest upcut or downcut bits?

[neilw20]

Ideally, low helix, downcut can leave burr below. upcut burr above.

[Devastator]

Ideally, low helix, downcut can leave burr below. upcut burr above.

Perfect. Burr below is fine, so I'll go downcut. Thanks for your help!

[keebler303]

HSS cutters will cut better when new (they are sharper), but carbide will maintain its performance for a longer time.

Matt