PDA

View Full Version : MAKING RING FORM, PROCEDURE



INTERPOLATE
02-21-2004, 04:31 PM
Greetings group. I must first send out a thank you to all who post helpful info here. I look forward everyday to firing up my computer and reading the days active topics. Learn something new here everyday. I have literally sat and read the archives till my eyes were dry and red.

Job is this:
I must make a bunch of rings from Nylon like plastic. The available material is in rod form.
The rings will have dimensions like: 1.613 X 2.192 x .390 in. Some smaller some larger. Typically IDs don't fall on any "standard" drill size.
They are used as spacers.
Tolerances are +/- .003"
Quantities are from 20 to 50 pcs. Might be as much as a few hundred sometimes.
Equipment available: CNC lathe/no turret just QC post. W/ collet closer and 8" 3 JAW.
Bandsaw.
I been just tubing them out using six in inch lengths> chucked up. Punching out with drill> boring> boring> and finish boring to size> Turn OD>. Parting off.
Chip control(or lack of chips,strings instead) is difficult with the plastic, so doing a 5-6" length is difficult to do any boring cycle since you really have to stay on top of whats going on in case of a clog.
Whats the most efficent way to go about these projects. Some clever tricks anyone?
Thanks!
JD



[This message has been edited by INTERPOLATE (edited 02-21-2004).]

winchman
02-21-2004, 06:51 PM
By working from both ends, you could get to the middle of a 3.5" long blank with a deep-cutting hole saw. That would reduce the amount of stringy chips you're having to deal with in the drilling/boring operations.

Roger

Evan
02-21-2004, 07:02 PM
Program it to back the tool out every rev or so and the string chip will break.

Rustybolt
02-21-2004, 07:22 PM
Since you've got CNC capabilities. After you've bored out the ID go back in with a boring bar shaped like a threading tool and back champher where you're going to cut off. It will save a hand champhering step and look a lot better.
It's a shame you don't have a collet set up, because you could rig a simple bar feed.

winchman
02-22-2004, 01:21 AM
Could you apply compressed air to the other end of the spindle to blow the stringy chips out of the hole?

Or, position the nozzle from a large shop vac near the tool to suck them out?

Part of the problem with the plastic chips may be the static electricity charge developed as they are being cut. I've noticed they stick to things, especially the chuck.

Roger

Dr. Rob
02-22-2004, 09:33 AM
FWIW, somebody gave me a general tip on turning plastic... Before you start, score the piece lengthwise, with a knife. That way the swarf tends to break off more easily. Doesn't help much when you're CNCing internally though.