Material Focus: UHMW-PE

Ultra High Molecular Weight Polyethylene aka UHMW is one of the most commonly used thermoplastics materials in the world. There are many reasons for this, but most engineers love UHMW for its excellent abrasion resistance, low coefficient of friction and it's tremendous impact resistance.

What does ultra high molecular weight mean?

Standard High Density Polyethylene has a molecular weight of between 10,000 and 100,000. UHMW has a molecular weight of between 3,000,000 - 6,000,000. The extra molecular weight of UHMW give it special properties that allow the UHMW materials to perform well where lower molecular weights fail. Abrasion, chemical, and impact resistance are all areas that the higher molecular weight flexes it muscles.

Where is UHMW used?

UHMW has an extremely wide array of uses, and is found in nearly every industry. To list just a few, UHMW is found in body joint replacements, gears, packaging machines, dump truck liners, bearings, and synthetic ice.

Is UHMW FDA approved?

UHMW is widely used in the food industry, and in general comes with FDA approval. It is important to note, though, that not all UHMW is FDA approved. Be sure and check with your plastic dealer or material manufacture before putting it to use in food applications.

Is UHMW weldable?

Yes and no. In general UHMW is not weldable, but there are a number a UHMW materials on the market that can be welded. Make sure to ask for weldable UHMW specifically when looking to order it from your plastics dealer.

What colors does UHMW come in?

UHMW can be found in nearly any color! Most commonly you will find UHMW stocked in virgin natural (white) and black, but material manufactures have many other colors available purchase.

Typical Properties

The typical properties of UHMW can be found here. It is important to note that these are generic properties and you should request to see that material manufacturer's data sheet to verify any given property.

Material Focus: Acetal

Before we dig into talking about Acetal, an important thing to note is that although Delrin and Acetal are similar materials, they are not the same! Delrin is a DuPont trade name for acetal homopolymer, while the name "acetal" is most commonly referring to acetal copolymer. The difference between them is slim, but worthy of mention. 

Where are acetals used?

The acetal resins are among the strongest and stiffest of all thermoplastics, and are known to have great fatigue life, low moisture absorption, high solvent and chemical resistance, and excellent electrical properties. Because of these properties, acetals often compete with nylons for many of the same applications. Bushings, gears, bearings, rollers, and wear strips are just a few common examples of how acetals are used. 

Are acetals FDA approved?

This is a tricky question to answer, mainly because there are a number of manufactures of acetal.  Some manufactures have their acetals FDA approved, and others do not. For this reason alone, its important to ask your plastic dealer or material manufacture for a data sheet on the material. 

What colors does acetal come in?

Typically acetals are found in natural and black colors, but are also available in blue.

Typical Properties

The typical properties of acetal can be found here. It is important to note that these are generic properties and you should request to see that material manufacture's data sheet to verify any given property.