UHMW is difficult to pick out in a pile of HDPE plastics, but it is a totally different thermoplastic.
In this article, we'll explore:
- What UHMW stands for
- Its unique qualities, and
- What makes it different from HDPE
Let's dive in.
What is UHMW?
Ultra-High Molecular Weight (UHMW) is the highest quality polyethylene (PE) available, engineered for extreme performance and a wide range of applications.
Because UHMW plastics are highly resistant to wear and tear, we use it for machining plastic components and chain guides destined for high-wear operations such as commercial and industrial conveyor systems.
Why is UHMW so resistant to wear?
Ultra High Molecular Weight is the secret of this polymer’s unique properties. Its high-density polyethylene resin has a molecular weight range of 3 to 6 million, compared to 300,000 to 500,000 for high molecular weight (HDPE) resins. That difference ensures that this material is strong enough to withstand abrasion and impact better than lower level plastics.
UHMW-PE cannot be transformed and molded by conventional plastic processing techniques (injection molding, blow molding or thermoforming). Instead, it is shaped using techniques more commonly used for metals. Compression molding and extrusion are the most common conversion process used with this resin because it produces a stronger, more consistent product.
5 unique qualities of ultra-high-molecular-weight polyethylene
All types of UHMW plastic used in our custom-fabricated parts offer the following five key characteristics:
1. Noise reduction
UHMW compounds interact as moving parts in such a way as to generate less noise through friction and contact with other components.
The unique molecular structure of UHMW polymers results in a self-lubricating material which exhibits excellent wear and abrasion properties as well as adding extremely high impact strength.
3. Corrosion resistance
UHMW polymers resist corrosion, making them ideal for applications that put them in contact with corrosive chemicals, such as acids.
4. Low friction
UHMW polymers feature a low coefficient of friction, well-suited for manufacturing chain channel, wear strips, belt scrapers, guides, and rollers. According to research, the co-efficient of dynamic friction of ultra high density polyethylene under dry conditions is around 0.1 (on average, which is low).
5. Low moisture absorption
UHMW has an absorption rate of less than 0.01%, making it popular for a wide range of marine and other applications that require exposure to high levels of humidity and moisture.
The high molecular weight a UHMW material is what gives it a unique combination of high-impact strength, low co-efficient of friction and abrasion resistance that outwears carbon steel 10 to 1. That’s why UHMW-PE is more suitable for many applications where lower density grades fail.
A plastic material worthy of mention that's frequently named next to UHMW is HDPE.
UHMW vs HDPE: Which is better?
HDPE stands for high-density polyethylene, and it is a petroleum thermoplastic used widely because of its appreciable moisture resistance, cost-effectiveness, and strength against chemical solvents. It's commonly used in building and construction since its short-polymer-chain molecular structure makes it a lightweight yet solid, durable plastic.
You'll find it in pipe fittings, containers for liquids like milk and alcohols, and plastic shopping bags. They even used it during World War II to shield high-frequency radar cables.
UHMW plastics' molecular structure, on the other hand, is made up of long polymer chains and a higher molecular weight than HDPE. Compared to HDPE, it doesn't absorb water at all and is a tougher, low-friction, and crack-resistant option.
This makes it ideal for sliding plates, screws, gears, and rollers. And that's why UHMW is a material of choice for custom fabrication of machining plastic components and chain guides at Slideways.
Interested in learning more about UHMW plastics?
To learn more about UHMW-PE and its uses, contact the UHMW polymer professionals at Slideways. We can help you select just the right UHMW product for your product and application.