On Jun 21, 2019, Jon Elson wrote
(in ):

On Fri, 21 Jun 2019 04:51:28 -0700, wrote:

I am trying to help a guy who is opening a machine shop. Which is kind
of comical since I have no experience in commercial machining.

He has a job machining peek plastic. And has a problem with long
strings of the plastic jamming the chip conveyor. Now I am a novice
but do know enough when confronted with a problem the first thing to do
is find out what others have done. So how do you deal with strings of
plastic?


The stuff is PLASTIC, of course, and therefore will just curl around
anything like that. Some plastics also produce a HUGE static charge when
cut, so the chips stick to everything.

The key is to use SHARP HSS tools intended for plastic, and to keep the
plastic from melting and gumming everything up. Even plain water used as a
coolant will prevent melting, and will drain the static electric charge away.
To keep corrosion of the machine tool surfaces down, it is traditional to
dissolve some bicarbonate of soda in the water. Do not use any kind of fat or
oil, as it will degrade the plastic.

As for chip breaking, the usual approach is to arrange for the chip to be
pulled away as fast as it is generated.

Joe Gwinn