plastic

[vvv_contractor]

Hello machinists,

 

what is a good plastic to machine on a small mill?

 

i have tried uhmw and nylon, results are very bad. i have tried pvc, it good, but i am looking for enomical plastic to practice my machining skill.

 

thank for any help in advance.

 

vvv_contractor

[DrewG]

Try Delrin. It is great to machine, always breaks the chip. I'm not sure what you consider expensive, but Delrin is considerably more than UMHW, but alot less than Teflon. You'll probably pay about 6.00 a foot for a 1.750 bar. It is the best, least expensive plastic to machine I've ever tried. It also looks like it's been molded when machined. Very little tool marks. Try it, I bet you'll be amazed.

[Fig sign]

+1 for Delrin .Also try technical wax

 

Delrin:

Used it a lot and like it .

I used it once many years ago for testing complex programs (and technical wax also and it is splendid to practice your technical skills )

It is like to cut butter.

 

Use 2 flutes mills or one -tooth special solid mill for plastics .

Well wax you can mill with any tool at all !

[crazy^millman]

Well you could also try Ren-Shape it machines easy holds the shape well and allows high feeds and speeds so you dont spend more time making soemthing than needed. Delrin is a good choice but UHMW is the cheap route of having problems machining UHMW use highspeed steel and very veyr postive sharp tools to cut it and shoudl see better results.

 

Crazy Millman

[Harryman]

Delrin is good stuff but ABS is cheaper, and also makes nice chips. If you're just looking to practice, I'd say go ABS. Nylon and polyethylene are soft and stringy. If you are going to be machining lots of plastics, it's good to know how these behave, but they aren't the most fun to work with. The best plastic I ever machined was polysulfone. They were small parts for a medical tool. The stuff held size nice, and made good manageable chips. I don't have any idea what it costs.

[Harryman]

Delrin is good stuff but ABS is cheaper, and also makes nice chips. If you're just looking to practice, I'd say go ABS. Nylon and polyethylene are soft and stringy. If you are going to be machining lots of plastics, it's good to know how these behave, but they aren't the most fun to work with. The best plastic I ever machined was polysulfone. They were small parts for a medical tool. The stuff held size nice, and made good manageable chips. I don't have any idea what it costs.

[Rekd™]

quote:

---

i have tried uhmw and nylon, results are very bad. i have tried pvc, it good, but i am looking for enomical plastic to practice my machining skill.

---

UHMW, (Ultra High Molecular Weight) is not so bad to machine. Moves around a lot.

 

Nylon isn't too bad either.. It's hairy around edges if you dont cut 'into' edges where ever possible. Use INSANELY HIGH speeds/feeds, or it will melt, making it even worse.

 

PVC is nice, but expensive.

 

Acrylics are nice, pretty results. Cheap when bought in small peices, very expensive when it gets thickerer.

 

Delrin is nice, but moves around, and seems a bit more 'slippery' than others, thus making workingholding more of an issue.

 

If you want to 'hone' your skills, you need to machine some tough stuff. Get used to the controls on something cheap and easy, (like my ex g/f ), then get yourself some alum, then some carbon steel, then some stainless.

 

While plastics are sometimes cheaper, they are not always easier to machine than some metals, like alum etc.

 

'Rekd

[MATT Q]

ABS is good stuff to practice on I don't know the price differences but that RENSHAPE material is the best I think but it is pricey. Depends on what you want.

[MetalMarvels]

The most important part is SHARP tools - carbide is usually too "blunt" and tends to "push" the plastic rather than cut it cleanly. HSS does nicely with most plastics but can wear quickly. Depending on the plastic, I usually climb cut the roughing and conventional mill the finish.

[Rekd™]

+1 Gary. Also keep in mind that a higher rake angle is good. Prevents chipping. i.e. use drills with a 135° tip angle vs 118°

 

'Rekd