Turning plastics and controlling the chips

G

garyhlucas

Stainless

Joined

Oct 17, 2013

Location

New Jersey

• Apr 21, 2017

• #1

I did a little PVC turning today on the manual lathe. Chip wrapping drove me nuts! We do most of our round plastic parts on the CNC mill, using a saw on an arbor. Big pile of chips, you can go do something useful while it runs, no problem. So just curious, do you guys that do plastics on a lathe use live tooling for chip control? Seems like roughing ab OD with an endmill would really eliminate the chip wrapping problem. I'm not much of a lathe guy which is why I ask.

 

C

CalG

Diamond

Joined

Dec 30, 2008

Location

Vt USA

• Apr 21, 2017

• #2

Strategic cuts to limit chip length (slotting operation)

Or a good shop vac plumbed thru a 55 gal drum.

Search, this topic has come up before.

 

Ox

Diamond

Joined

Aug 27, 2002

Location

Northwest Ohio

• Apr 21, 2017

• #3

Yes - I don't run much plastic, but with my more recent apps I was running UHMW and decided to try roughing it with a mill, and it werked SUPER!
Only turned the finish pass.


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Think Snow Eh!
Ox

 

H

Hazzert

Stainless

Joined

Dec 21, 2014

• Apr 21, 2017

• #4

I've never needed to do it but if I was having issues I would break the contour into 3/4-1" long sections and rough each individually then take a whole contour finish pass.

If I was aiming for ultimate efficiency I might long hand the roughing and add in micro-dwells; the same idea as disengaging the feed on a manual lathe to break long stringers.

 

Ox

Diamond

Joined

Aug 27, 2002

Location

Northwest Ohio

• Apr 21, 2017

• #5

The live tool is pretty efficient....

... and the pile of chips is nothing compared to that rats nest that you had a 1/2 hour ago!


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Think Snow Eh!
Ox

 

TeachMePlease

Diamond

Joined

Feb 11, 2014

Location

FL

• Apr 21, 2017

• #6

One of the things I learned here on PM is using an endmill to rough a slot close to your finish depth, then turn, in a live tooled lathe. That said, I don't get to deal with this problem much because I do Swiss, and 95% of my plastic work is PEEK, which you can feed just like aluminum with good results, and I also have directed high pressure coolant for every operation I deem it necessary.

 

D

deadlykitten

Banned

Joined

Aug 5, 2016

• Apr 22, 2017

• #7

TeachMePlease said:

One of the things I learned here on PM is using an endmill to rough a slot close to your finish depth, then turn, in a live tooled lathe. That said, I don't get to deal with this problem much because I do Swiss, and 95% of my plastic work is PEEK, which you can feed just like aluminum with good results, and I also have directed high pressure coolant for every operation I deem it necessary.

Click to expand...

hy mr please can you provide more details about the endmill ? rough where, how ? the mill is paralel to Z ? and if the mill is shorter than the part ? just asking

about the PEEK : i craft from time to time some parts called PEEK, and i always wondered who called tham like that now i see, actually the client called them like that because of the material : he was also sending me the material nice once / thx

 

M

MrSteve

Aluminum

Joined

May 26, 2014

Location

Boston/North Shore, MA, USA

• Apr 22, 2017

• #8

End mill a slot (can be narrow) parallel to the rod axis, not quite as deep as the final radius. Turn to final radius. Slot breaks the chip once/revolution.

 

plastikdreams

Diamond

Joined

May 31, 2011

Location

upstate nj

• Apr 22, 2017

• #9

MrSteve said:

End mill a slot (can be narrow) parallel to the rod axis, not quite as deep as the final radius. Turn to final radius. Slot breaks the chip once/revolution.

Click to expand...

This...Also run with your tool upside down and a ton of coolant. PVC is a pain because it basically melts and sticks to anything so if you keep it cool if will stay more solid and break up as it goes...I think the Tg is just above room temperature lol.

 

C

CalG

Diamond

Joined

Dec 30, 2008

Location

Vt USA

• Apr 24, 2017

• #10

Excuse my innocence, but with a NC lathe, would it not be too much trouble to make a "broaching pass" with the spindle stopped, depth to equal the following turning pass?
It might require a custom grind on the tool tip, but hey! It's plastic!

Note:
I've got a 1/2 inch HSS bit with a hole EDM'd in one corner, The edge is honed right up to the hole. The plastic runs through that hole like a rabbit through sticker bush. Not so much for sharp corners, but with a vacuum hose against the dirty end, it's a plastic hog's dream!