Drilling micro holes in delrin .0125

[LexLuthier]

Hello, I am getting ready to drill .0125 holes (#82 drill) in delrin and would like some recommendations on rpm,feedrate, and peck size. Hole depth is .1875. I am doing 5 parts with 100 holes each. I ordered some carbide circuit board drills that have .216 flute. My mill has a max rpm of 8000 and has flood coolant. If anyone has experience doing this sort of thing I would appreciate some recommendations.
Thanksmuch
Jay

[DSIF]

Wow. You have a real challenge on you hands. I have done small holes in plastic,but not that small. Keep in mind that you are attempting to drill with a piece of wire.
Delrin (acetal) was made to machine,it's a pretty hard plastic and should not try to melt on you.
If you have ER collets,use a .5mm and chuck up on the drill as far as possible. Rap the spindle up to 8000 and see if the drill spins straight. If not,you will have to find the "sweet" RPM. Turn your coolant pressure way down. The force of the water pressure will make the drill deflect and not spin true.
Try 8000 RPM,.003-.005 peck, 1.0-1.5 IPM feed to start. Adjust to get desired results. Good Luck!
Dan

[leggazoid]

These drills are good.


#82 CAR MICRO DRILL :: Solid Carbide Micro Drills | Travers Tool

[LexLuthier]

It wasn't as bad as I thought. I used 3500 rpm, f4, .03 peck with a carbide circuit board drill .I had to hit feed hold a few times to blow chip wrap off the drill. I need to stop psyching myself out.

[neilw20]

You just have to scale down your brain. It is just like big stuff, except you can't see it properly (at my age)
I just pecked drilled some 1.5mm deep slots 4mm long x 0.6mm wide in plastic, with air blast.
Didn't even break the carbide PCB drill and it was 8mm long.
Interesting watching the drill bendies under good CNC control.
Once through, I went down 5mm and used it as a milling cutter, even though a drill has little or no clearance, but maybe the PCB drills for plated through high surface finish holes have some clearance.??

I can't measure that good.

Just held the 1/8" end if the shank in the big chuck, and got it centered after a few goes.