What machines better HDPE or UHMW?

R

RJT

Titanium

Joined

Aug 24, 2006

Location

greensboro,northcarolina

• Jun 4, 2019

• #1

My customer says either will work for this application, basically just a cradle to hold a part for assembly, but it has a tremendous amount of milling on it. I've machined UHMW but don't think I have ever machined HDPE. Which would you rather?

 

4GSR

Diamond

Joined

Jan 25, 2005

Location

Victoria, Texas, USA

• Jun 4, 2019

• #2

Me, neither. I think Delrin is a better choice, but what do I know.

 

A

adh2000

Titanium

Joined

Dec 21, 2005

Location

Waukesha, WI

• Jun 4, 2019

• #3

Anything is better than UHMW. HDPE will machine better, better finish, better dimensional control. Teflon is even better if that is an option. Might be too expensive.

 

P

pops2004

Plastic

Joined

Aug 17, 2015

Location

Alvin Texas USA

• Jun 4, 2019

• #4

I machine a lot of plastic for customers. Some of it I get a friend with some CNC machines to help. I like Acetal Copolomer. Really get a nice finish. Works great on CNC lathes too. I buy it on amazon.


Sent from my iPhone using Tapatalk

 

L

Limy Sami

Diamond

Joined

Jan 7, 2007

Location

Norfolk, UK

• Jun 4, 2019

• #5

I've never noticed that much (if any???) difference between the 2 PE's

 

RC Mech

Stainless

Joined

Jul 21, 2014

Location

Ontario, Canada

• Jun 4, 2019

• #6

As above, HDPE machines nicer. UHMW is marginally more gummy, longer polymer chains, higher shear strength, tears.

Delrin is easy to machine. Over-specified by those who don’t care to appreciate other polymers IMO.

 

G

guest

Guest

• Jun 4, 2019

• #7

Limy Sami said:

I've never noticed that much (if any???) difference between the 2 PE's

Click to expand...

Same here. The machine doesn't even know it's there. I'd be very surprised if someone could distinguish between the two based only on machinability...

 

4GSR

Diamond

Joined

Jan 25, 2005

Location

Victoria, Texas, USA

• Jun 4, 2019

• #8

Used to use Nylon 101 as bushings to hold and support long steel tubes and held up fairly good. IT's cheap, probably does not hold up in comparison to HDPE. They all will fail from cold flow under dynamic or static loading if the loads are high.

Delrin is from the Acetal family of polymers. They machine nice as HDPE, but I suspect they are little bit more expensive. Haven't priced it in many years.

 

L

Limy Sami

Diamond

Joined

Jan 7, 2007

Location

Norfolk, UK

• Jun 4, 2019

• #9

FWIW Acetal is getting on for 1.5 x the price of HDPE


Ref (these are just guide prices from a supplier who posts their prices - you can do much better) Acetal Rod - Direct Plastics Limited & Acetal Rod - Direct Plastics Limited

 

J

jrmach

Titanium

Joined

Jun 9, 2012

Location

Boise,Idaho USA

• Jun 4, 2019

• #10

Delrin is just some fun and a pleasure to machine

 

C

coyoinu

Aluminum

Joined

Oct 6, 2012

Location

Orange county, CA

• Jun 4, 2019

• #11

uhmw isn't so bad. high feed, low speed, positive rake cutter

 

P

petersen

Cast Iron

Joined

Dec 13, 2008

Location

minnesota

• Jun 4, 2019

• #12

UHMW and HDPE are quite similar to machine; however on thick sections and

deep machining, the UHMW will warp much much more than HDPE.

Chose HDPESR (stress relieved) for those conditions.

It is also generally cheaper than UHMWPE.


petersen