I need to make up a small camera mounting enclosure using the Lathe and Mill. As I have never machined plastic before my knowledge on this subject wouldn't fill up the back of a postage stamp. I believe I need a peice about 50mm x 50mm x 300mm fairly ridged black plastic. Can anyone point me in the right direction as to what plastic to use?
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Wendelspanswick
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Delrin or Acetal* and Nylon all machine really easily compared to steel and non ferrous metals.
*Trade names for the same thing.
*Trade names for the same thing.
wristpin
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CRB
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Probably too brittle since I would expect it to have slots machined, and not to be treated like an ornament.
Having a look soon.
Oooer, this stuff is a law to itself. It doesn't like my indexable tooling, leaves a finish rougher than desperate Dans chin. It turns nice with a sharp HSS cutter though. I have found if I leave it in the lathe over night and take a light finishing cut in the morning the tolerances are not too far off. Is it best to turn it first or bore it first?
Run you machine as fast as you can but low feed rates, SHARP hss tooling, if you have a way to rig up air blast cooling that helps, or coolant as a not so good option. It expands a lot with machining heat and as youve found getting it near and sneaking up on the final dimension when its cooled helps a lot.
Its best to turn and bore it without taking it out the chuck at all, if thats what you are meaning?
I would always bore a part first by habit as its more awkward to get a hole accurate and measured up than it is a od unless you have some internal micrometers. Not so important now but you have to get in good habits for the future.
Deburring with a razor makes it easy. Delrin however is really nice to work despite the above, nylon, now thats horrid. I like PEEK but my wallet doesnt.
Its best to turn and bore it without taking it out the chuck at all, if thats what you are meaning?
I would always bore a part first by habit as its more awkward to get a hole accurate and measured up than it is a od unless you have some internal micrometers. Not so important now but you have to get in good habits for the future.
Deburring with a razor makes it easy. Delrin however is really nice to work despite the above, nylon, now thats horrid. I like PEEK but my wallet doesnt.
Since nobodys mentioned it, delrin is also quite flammable. Its polymerized formaldehyde, which when heated turns into formaldehyde gas which burns like alcohol with almost no flame. PVC is self extinguishing which is why they use it for electrical wiring insulation.
May not be a huge worry for your camera housing, but if anyones thinking about knocking up some electronics psu projects in delrin boxes, may be worth taking into account.
May not be a huge worry for your camera housing, but if anyones thinking about knocking up some electronics psu projects in delrin boxes, may be worth taking into account.
I find Delrin gives a much nicer finish that Nylon. Delrin can be finished to almost mirror like. Nylon always seems to end up with a satin finish. I just finished making some preload spacers in Nylon this morning. Bored them out to just under 3/4" and then used a 3/4" reamer to finish. I prefer Delrin though and tend to do anything that needs a plastic out of it.
CRB
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Nylon, 6 particularly almost 10%, absorbs water readily. Polycarbonate and ABS are the same, forming them without drying them first, boils the water within forming bubbles.
Machining dry polycarbonate is extremely noisy, brittle sounding, but 'wet' is dull sounding by comparison. None of the machining I have had to do was so close tolerance, that I am able to comment on the difference between wet or dry materials.
I would be interested to know however.
Machining dry polycarbonate is extremely noisy, brittle sounding, but 'wet' is dull sounding by comparison. None of the machining I have had to do was so close tolerance, that I am able to comment on the difference between wet or dry materials.
I would be interested to know however.
DanielW
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Always check out ebay for off cuts with both plastics as its cheaper for the round bar stuff,nice stuff to turn on a lathe.
http://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&_nkw=acetal+bar&_sop=2
http://www.ebay.co.uk/sch/i.html?_o...C0.A0.H0.Xdelrin+bar&_nkw=delrin+bar&_sacat=0
http://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&_nkw=acetal+bar&_sop=2
http://www.ebay.co.uk/sch/i.html?_o...C0.A0.H0.Xdelrin+bar&_nkw=delrin+bar&_sacat=0
