cutting phenolic??

[myxpykalix]

I got a PM from someone with this question and I don't have enough experience to answer knowledgably so let me ask here:


I have a local ShopBot owner willing to cut a router insert into a sheet of canvas phenolic but he's never done it before. Can you recommend the feeds and speeds and the specific cutter that you would use?

Can you give some answers here since i don't have enough experience with plastic to give him proper advice? :D

[garyb]

Onsrud 67-200 series, three flute SC Phenolic cutter
available in 3/8 or 1/2", up or downcut.

sorry don't have my book with me to give the feeds & speed
Gary

[jlholu]

Gary,

Thank you for the quick reply!

Is this a roughing or finishing cutter? What is the significance of up or down cut other than how the shavings are removed? Should I use a down cutter if I have a blind groove or hole?

Jim

[myxpykalix]

Jim,
I tried to reply to your PM but the system wouldn't let me. I figured more people would have experience here.:)

[garyb]

finish tool - 3 flute 10° helix (almost a straight cutter)
120ipm, 10-11k rpm (.002-.01 chipload)

In general
Upcut will clear the chip = less heat longer tool live, may lift part from table with poor holddown (but as heavy as phenolic is i doubt it) May also chip top edge of material.
Downcut, is obliviously the opposite, chips are forced down into the cut generating more heat at the tool, forces material down to the table so helps with hold down, cleaner top edge.

phenolic is a hard and heavy composite material, I have not experienced top edge chip out using an upcut which is my preference (have snapped a couple of points of 22° v-bit though)

[br928]

When you say "canvas phenolic" is that a brown colored micarta material? If so, I have used a 'good for everything' Super O single flute upcut with good results.