Drilling holes in plastic? CNC?

11/16/18, 2:00 PM #1

Barry Irby
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Drilling holes in plastic? CNC?

Barry Irby

A friend got a little CNC machine to play with and learn on The bed on it looks like it will receive a piece about the size of a sheet of paper and the chuck appears to be a 1/8" collet.

He was trying to drill a grid of about a thousand 1/8" holes in a piece of 1/4" plastic to make a vacuum hold down. At about a hundred the bit over heated and melted a glob of it onto the tip and he did an "emergency stop".

I don't know exactly what type of plastic. It's clear is about all I know and was salvaged from some other project.

The bit was an ordinary twist drill bought from Home Depot.

There are many variables he can adjust, RPM, plunge rate, pause between holes, Etc.

Any advice on type of drill bit, speed, Etc. would be appreciated. How about Air pickup for debris and to cool the bit?

Re: Drilling holes in plastic? CNC?

11/16/18, 2:10 PM #2

JohnV
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Re: Drilling holes in plastic? CNC?

JohnV

air blowing would have more cooling effect than suction. Think an arrangement like a jig saw.

Re: Drilling holes in plastic? CNC?

11/16/18, 3:38 PM #3

Dick Coers
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Re: Drilling holes in plastic? CNC? *LINK*

Dick Coers

Get a plastic drill bit. Greatest invention ever! Sharper point angle, but ground like a scraper. Also tell him to use a pecking drill cycle in the program. Usually those little machines use Dremels or similar and that means way too fast of rpm.

https://www.eplastics.com/accessories/plastic-tools/drill-bits

Re: Drilling holes in plastic? CNC?

11/16/18, 6:53 PM #4

Tony - Memphis
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Re: Drilling holes in plastic? CNC?

Tony - Memphis

Don't know about his machine, but drill bits are a no no on my machine. I use end mills for drilling. What is the RPM of the spindle? You might look at that and compare to the rated RPM for a twist bit.

I just finished a small vac table (mdf though). Lots of tiny holes! Seems to work pretty well though. I use a shop vac with it!

Re: Drilling holes in plastic? CNC?

11/17/18, 1:00 AM #5

Barry Irby
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Barry Irby

He managed to get it done. the first 100 holes of so were done with a Ryobi bit and that gave him a fit. It tended to melt the plastic and left a little volcano around the opening. He tried air and vacuum and even spritzed it with a spray bottle. Then he switched to a Milwaukee bit and it worked significantly better. Little or no rim around the holes, no more melting.

I don't have any comparison data on the two bits so I have no information on why one worked better than the other.

Drilling holes in plastic? CNC?

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