[RyanSwiss]

Hello Everyone,I currently work with a Citizen Sliding Head lathe have so far been machining various metals. However would now like to go in the World of PlasticsAware that special and New collets and Guides are needed as you will never get one size of Plastic rod exactly the same as the next. Unless you want the expensive option of grinding it, that's the knowledge found out so far.Some Plastics will absorb water such a nylon, Some will expand and then cool into tolerance.However there seems to be very little Machining Knowledge out there in terms of feeds and speeds? To use coolant or Not to use coolant?Tried Acetal so far which comes of in streams of Ribbon, Wraps itself around everything and the components pop out in a furry mess that take too long to unravel so unproductive. There no way you could go on a production Run.Generally manufacturing Components less than 20mm.Any one there have any experience with working with any Plastics and any info as to how they achieve a good product at the end of it. The worst part is the ribbons of swarf wrapping around the component.Or is this Super protective knowledge that no one will share.Will try and keep this an active post and keep everyone updated on various Plastics out there on machining if people don't mind sharing knowledge.

[z369]

I'd suggest contacting your tooling rep and maybe even Citizen themselves. I've never run plastics in a Swiss before, but I have on conventional lathes and there we had coolant clogging issues and use the sharpest tooling you can. Are you running cutting oil or water soluble? The other issues I can see running plastics in a Swiss are A) Guide bushing shredding the bar B) Bending issues at higher RPM.

[Thunder27]

We use cold air blasters instead of liquid coolant. Something like these https://www.vortec.com/cold-air-guns. This eliminates the problem of chips clogging your coolant. It also gives you the ability to direct a turning chip exactly where you want it. You may need a couple of them, but doing so you can direct the chip into the bottom of the machine and away from your tools. This is how we keep long chips from wrapping up on our part or tools.

[cosmo2000]

What model Citizen?
What grades of plastics are you going to be machining?

[cosmo2000]

Hello Everyone,I currently work with a Citizen Sliding Head lathe have so far been machining various metals. However would now like to go in the World of PlasticsAware that special and New collets and Guides are needed as you will never get one size of Plastic rod exactly the same as the next. Unless you want the expensive option of grinding it, that's the knowledge found out so far.Some Plastics will absorb water such a nylon, Some will expand and then cool into tolerance.However there seems to be very little Machining Knowledge out there in terms of feeds and speeds? To use coolant or Not to use coolant?Tried Acetal so far which comes of in streams of Ribbon, Wraps itself around everything and the components pop out in a furry mess that take too long to unravel so unproductive. There no way you could go on a production Run.Generally manufacturing Components less than 20mm.Any one there have any experience with working with any Plastics and any info as to how they achieve a good product at the end of it. The worst part is the ribbons of swarf wrapping around the component.Or is this Super protective knowledge that no one will share.Will try and keep this an active post and keep everyone updated on various Plastics out there on machining if people don't mind sharing knowledge.

Delrin is a dream on my swiss. I am making some .26"dia by 2.25" long parts and they scream. We do not run coolant at all. The residual oil left from the bar feed is the only oil we need to clean off the part. Delrin parts should be cleaning in pure alcohol because it will absorb water and swell. The only problem with holding .0005 would be that the parts do shrink and grow with the change in temperature from machining. In my experience the shrink about .002 on the diameter from hot off the machine to ambient.

Chip control will be the only problem, use super high feeds and air blasts to clear the chip. Also the cabinet air will make your eyes burn similar to chopping an onion due to the acetic acid that is off gassing from the machined parts.

[cosmo2000]

Delrin is a dream on my swiss. I am making some .26"dia by 2.25" long parts and they scream. We do not run coolant at all. The residual oil left from the bar feed is the only oil we need to clean off the part. Delrin parts should be cleaning in pure alcohol because it will absorb water and swell. The only problem with holding .0005 would be that the parts do shrink and grow with the change in temperature from machining. In my experience the shrink about .002 on the diameter from hot off the machine to ambient.


Chip control will be the only problem, use super high feeds and air blasts to clear the chip. Also the cabinet air will make your eyes burn similar to chopping an onion due to the acetic acid that is off gassing from the machined parts.

Also I would consider the adaptive guide bushing
They are wonderful

http://www.marucit.com/accessories/accessory-bushing.html

https://www.s-mcollets.com/cnc-collet/

http://bpt.com/usr/pdf/collet/2384.pdf

[hfjbuis]

For turning plastics you need very sharp tools. For that, insert tools will probably don't work.
You have to avoid heating up the workpiece, lower spindle speeds will help and avoid rubbing so don't take to thin cuts.
POM is good to start with and i have read PVC can be turned well. I also turned Poly Acrylaat, that hard clear plastic, in small 3 mm diameters.
For turing plastics i use flat (0°) angled tools, the same as for turning bronze.