Coolant thru drills in plastic

[Tim Johnson]

Is anybody doing this? I'm looking for speeds/feeds. The drill manufacturers appear to be guessing at what the they are. (also for copper) Today it's for PEEK, though most of our plastics are DELRIN, ULTEM and PVC. The coppers I run are 110 and 145.

[Thee Cutterman]

Tim

I used to drill a lot of delrin at my last job and i don,t miss the stuff one bit. We also had a lot of problems with speed/feed. I ended up going with Iscars chamdrill jet with a IDN grade insert.

from memory we were running a 10mm drill at 180M/Min ,0.25 -0.6MM. I,ve never tryed them on copper so i,m not sure how they would go.

 

Darren

[Joels]

i machine delerin everyday on a fadal vmc. one example is we drill using a guhring 7/16 drill at 20 inches a minute at 1500 rpm. the biggest problem is the chips breaking up so they dont wrap on the drill so we have to use a peck cycle which takes more time.

[kinglouie V]

through coolant drills ALWAYS seem to help in this

situation. the plastic wants to melt (weld) to tool so for sure more pecks but the coolant will help to minimize the pecks. I got a job coming up using peek but will probably get to it after your done. one thing I know well about it though is having a 'very keen' edge on your tool. thin those webs out on those drills too.

[Lucky]

We drill Delrin dry with a heavy chip load and pecking very successfully. The thick chips do not wrap around the drill to cause problems.

[Tim Johnson]

Thanks for the info guys.

quote:

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through coolant drills ALWAYS seem to help in this

situation. the plastic wants to melt (weld) to tool so for sure more pecks but the coolant will help to minimize the pecks.

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So I take it that you can't drill the holes without pecking? What speeds/feeds do you use for the coolant drills? I just used a HSS drill for this job (prototype) but was curious as to if a coolant drill would eliminate pecking. Typically I feed plastic hard (1/4" at s6876 f101.12 for DELRIN with hss) but to get rid of pecking really knocks off a lot of time.

[Joels]

i searched for special drills to break up the chips but i could not find any. I even asked the vendors at Westec last year and they didnt have any so i asked the Fadal rep at the show and he said to set the machine to peck to break up the chips. I run 4 parts on a pallet and if i dont peck by the time the drill gets to the last part it may have enought chips on the shank to rub and burn the 4th part. It is slower but i need good parts and i cant stand at the machine to watch it. I run a Fadal 4020 with thru the spindle coolant and it worked great but it keeps leaking in the housing thru the seals and ruins the belts so we dont us it and we have had Fadal out twice for this and they cant fix it so we dont use it.

[Surface]

If it is peek that you are drilling, then I would not try to push it. That material is EXPENSIVE. 1x1x24 costs around $300. It cuts easy, but unless you can afford the loss, slow it down and take your time. It may prove more profitable than screwing up a part. jm2c

[Tim Johnson]

What I don't like about PEEK (other than deburring that crap) is if you're machining tighter tolerances (+/-.001) the material will grow on you if you try to cut it too hard. Not as bad as teflon but that can ruin your day.

[35K chipper]

Try glass bead blasting your PEEK part at 20 psi. bead diameter .005>.010 to remove burrs. The material has glass in it so use carbide circuit board drills ane diamond coated endmills from harvey tools. There is a design and fab guide from DSM engineering plastics with feeds and speeds for many engineering plastics. Use a peice of polycarbonate for a setup peice it will save you $$$.

 

35k