Drilling medical grade Peek

[mike561h]

Hi Friends,

 

Just wondering if anyone has drilled 1/32 holes .500 DP in peek. I cannot use coolant.

I was ordering a cold air nozzle to tackle the .035 drilled holes on the parts. I don't want to spray ionized water while drilling cause the machine will rust and the 5c collet holder. I'm running max 4000 rpm at 1.2 IPM peck .02.

I have been there before where the plastic melts while drilling. The drill snaps. you know the scnerio. I hate it.

 

Thanks

[Philcott]

Hi Mike,

 

We have drilled peek before but we have been able to use coolant and the holes were .165 dia.

 

As you know you need to keep the tool cool or the chips will melt. (good application for the expression "Keep a cool tool")

 

I would think if you use air, keep the RPM down and retract the drill all the way out of the hole you should be ok even with out coolant. If you have problems maybe you can drill each holes .1 deep then come back and go another .1 repeating the process until you get to full depth. This might allow the material to not get too hot.

 

Good luck and let us know what works.

 

Phil

[dolphin1]

this is where i would start 3820 rpm 1.67 feed and .007-.0105 for peck.

hth

[TR Mfg.]

RPM's sound high? I would start at 2100rpm and 2ipm .025 pecks.

[Paul Felger]

why cant you use coolant with a mister? good coolant wont allow rust. A good sharp new drill and a little mist of coolant will do fine, even with the 4000rpm, just retract more to cool it down and get the shavings off. If it is not production why not use a spray bottle with light oil? not sure about oil properties with peek, but I have turned a sh%t load of it and some times I use diluted degreaser in a spay bottle.

but it was never production, hope I helped.

[Philcott]

Paul,

 

quote:

---

why cant you use coolant with a mister?

---

I would guess it's because of contaminating the part with oils. Mike called it Medical grade Peek so this would be my guess.

 

Phil

[Jaz]

Plain de-ionized water in a mister would help and not be as bad as flooding for rust.

 

Look into some kind of oil or fluid that would be acceptable as a contaminant or see if there might be an acceptable method of cleaning parts after machining.

[Leigh @ Kodiak]

One thing to watch out for if you use air. On a 1/32 drill, too high of a presure air can easilly bend the drill.

[RDub]

I have drilled many a holes in peek, without the allowance of contaminants down to .016" diameter. Not fun, the cold air gun really helped us, until it gets there, I would typically use a higher reference plane to allow a little more time for chips to come off the drill. When the chips were persistant we would actually have the operator sit there with a soft brush and rub it against the drill on the up movement to remove the chip, of course we had to override the rapid to about 25%. We only moved the brush parallel to the table rather than with the spindle to make sure it didnt get sucked into the hole.

Also, PhilCott's method of going .100 deep in each hole before returning to the first hole to allow the material to cool can be really helpful as well.

[mike561h]

I have been running at 2000 rpm and 1.4 ipm with cold air. .020 peck so far so good. when I was running higher rpm you could see the drill getting hot. 20 more parts to go.

 

Thanks guys.

 

implant parts cannot be used with coolant.