Deep hole drilling on Polycarbonate\lexan

[Tamir Alon]

Hi there

Hello everyone.
I run into a serious problem when I try to drill small diameter deep holes in polycarbonate. Drills with a diameter of 1-2 mm at depths of 40-60 mm. The diameter of the hole is not uniform, and the surface finishe quality is not satisfactory.

what can be done? I would appreciate advice from the experts.

what extra lengh drills are reccomended?

feeds and speeds? pecking??

thanks!!

post Scriptum. It is about both CNC milling and CNC turning

[Leon82]

It's probably welding to the drill causing it to enlarge parts of the hole.

I would think something uncoated would be best. I would Try cutting the spindle speed and increase the chip with a small peck. Maybe a parabolic drill 

[#Rekd™]

Make sure the coolant is blasting the on the tool or use through spindle coolant if you have it. Peck drilling cycle with the pecks set to 1/2 the diameter of the drill.

 

[cruzila]

Heat is your enemy. SFPM can be too high, or the chip is not flowing up the flute of the drill. peck of 50% or even less depending on the drill. Carbide might work better for a smaller drill. Some coolants can cause Polycarb to craze so use caution there as well. Maybe air blast instead.