Tapping small holes in polycarbonate

[gromit68]

I have a job where I tap 15 holes 0-80 in polycarbonate, drilled and tapped thru .125" thick. I have always drilled the holes in a cnc vert mill and hand tapped them using hand tap in a tapper in a drill press. I'm curious if anyone has any advice for doing this in a VF-1 with rigid tapping? This run will be 15 holes per part in 250 parts.

[Geof]

I have tapped plastics including polycarbonate althoug not that small. You should have no problems except watch for chips curling around the tap and getting in the way on the next hole. Probably when you are hand tapping you have had to brush the curly chips off between holes. How you can do this in the machine I don't really know; clamp a toohbrush somewhere and have the machine move over and brush the tap off between holes ?

[axis]

use a form thead tap or a roll form tap there are no chips

[ltmquik]

Use a roll form tap. For 0-80 use 1400 RPM and 17.50 IPM and coolant on. Applying a bit of stick lubricant or applying some cutting oil to the holes prior to tapping will help also.

[Surfacefeet]

You should have no problem doing them with the Rigid Tap on your machine.