Pastics..help machining

[Kool Parts]

Lets talk plastics. The outfit I want to order from has
High, and low density polyethyene,
Natural Nylon 6/6,
Cast Nylon 6 with Molybdenum Disulphide,
All of these are in square bar form. My only need is a nice finish. The cast is black, and that would be prefered, but not a deal breaker.
Gary

[mxtras]

All of these are very, very easy to machine. HDPE is the cheapest, the MD Nylon (Nylatron GS) is more expensive. HDPE machines with a great finish (so does the MD Nylon) but is just a hair more difficult to 'deburr' than the Nylon. Nylons will absorb moisture and so will the HDPE - dimensional stability and UV protection are some of the properties to consider. The MD Nylon is the most stable on the list but is far more expensive.

I have attached a cost comparison between numerous plastics and other materials - this was done a few months ago when I was searching for an inexpensive prototyping/proofing material. THis file may have more info than you need, but here it is.

You may want to look at the Acetals. Very pricey, though.

Scott

[Kool Parts]

Scott,
Thanks, I will keep that for future ref. One of my guys remided me that MSC carries Nylon... Duuuu.
And its in black. They offer a Nylon6/6 and a 6/6 that is MDS filled. They claim better machining a increased lubricity. But its is cheaper?? Sounds like the way to go. Normaly better is not cheaper
Gary

[lakeside]

also for materail Mcmaster Carr has materail property and user info on web site and carries all above

[tobyaxis]

Originally Posted by lakeside also for materail Mcmaster Carr has materail property and user info on web site and carries all above

You can check out www.use-enco.com as well.

[Kool Parts]

Thanks for the replies,
I am going with the nylon. As far as properties go..I just needed a step above wet newspaper..Just really need a nice finish.
Gary