Small hole drilling in polycarbonate

[StephenK]

Haven't been around for some time and it's great to be back.
I'm having a problem drilling a .025 hole at .475 depth in a polycarbonate part. I tried different speeds and tried to vary the depths to no avail. Still can't get a straight hole.
Help with this subject would be appreciates.

Stephen K.

[squirrel]

Your drill might be broken, look at the point under a microscope. A solid carbide drill will run straight, and a HSS should work fine.

[Forrest Addy]

Polycarbonate melts easy and acts gummy. Use water with a little soap in it as a coolant.

Feed slow using a good drill you've inspected under 10x magnification.

Peck drill, clearing the chips frequently. Blow the hole and the drill clean before re-entering.

That's a deep hole for the diameter. Make sure the drill is spotted correctly. If the drill starts off center, it will follow and exaggerate the error.

[Black_Moons]

while nature/drill size tells you to run at high rpm, Molten plastic will tell you to run low rpm.

Expect to have to use feed rates similar to glaciers ice flows.

[George_Race]

I have had good luck drilling all kinds of plastics using a carbide 2 flute center cutting end mill. Run it very slow, around 500 RPM's and you can go quite deep if you peck drill it as well.

George

[Black_Moons]

George makes a good point, Anything solid carbide will be MUCH more rigid then anything HSS, And at 0.025" it will even be affordable! maybe..

[StephenK]

My thanks to the tips that I received from the guys on the forum. A combination of ideas payed off. I was able to drill nice clean straight holes .025 by .475d without a problem. Slow speed, about 130rpm, pecking and cleaning and for the lubricate I used mineral oil. I tried water and soap and that caused it to bind. Thanks again for your help.

StephenK (NJ)