Is hdpe melting?

CNC Machines Shapeoko 4
1

I’m trying to drill small holes (.078") in 1/2" HDPE with a 1/16" O- flute. I think the HDPE is melting because I can’t seem to get the nail (.0725") all the way into the hole. The top of the hole is wide enough but gets too narrow less than 1/4" in so the nail only goes in partially. I don’t want to drill much wider for fear of making the hole too big.

any suggestions

Thanks
Jim

2

Try a full retract after every peck.
Keep the peck depth around one diameter.

Just a guess

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3

The bit is probably flexing at that depth. If you are drilling holes frequently enough, you may want to get a bit that is the diameter of the hole you want.

These carbide drills have 0.400" flute length if you aren’t going all the way through the 0.500" material.
https://www.ebay.com/itm/387365476078

This end mill has a 0.590" depth due to the relief cut after the flutes.
https://www.ebay.com/itm/154562209729

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4

Thanks Jim. That really helped

Jim

5

Are you using a regular twist drill? A mill drill would work better on these machines.
And you should have the RPM at the lowest speed you can get.
Air blast, or even mist coolant will help dissipate heat.

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