Posting this here in case we have a plastic guru incognito...
I have a customer who bought a machine back in '05. Since day #1, they have
been trilling this material they call "Torlon PEI" with a. 0.029" drill at
around 10,000 RPM
The material is 3/8" thick and they have no problems making the hole itself.
I thought they would have to peck drill it, but apparently not...
The drill rapids up to the surface, takes a controlled feed rate from 1/16"
prior to the end of stroke (clean through) and retracts at rapid speed.
Much like a CNC would but with a simple, but highly controllable hydraulic
feed control doing the dirty work.
Now that every penny counts more, they found that the process leaves a burr
on the product that they have been removing since day #1 by hand. They want
to try and drill without getting that burr..
Here's the kicker... The burr is at the entry side, not the break through
My first thought was that they were controlling the feed rate too late and
that the drill was entering the material fast, then slowing down and
completing the stroke. They claim that is not the case and that the feed is
100% controlled from entry to breakthrough. They also claim that the burr
shows up when entry happens and not during the process.
Anyone have any tips, thoughts or misc. ramblings on what might be causing
RPM or other suggestions, thoughts? Etc... Can't really go above around
11-12,000 RPM on this application due to machine limitations.
My next suggestion to them was to try and get a small countersink bit but
they are using a drill bushing to make sure accuracy is held very tight.
Can't use a drill bushing in that case...
Joe Agro, Jr.
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com