Material guide
UHMW vs HDPE: Which Polyethylene Do You Need?
UHMW and HDPE are both polyethylene, but they behave very differently in wear, impact, welding and cost. Here's how to pick the right one for wear strips, cutting boards, liners and marine parts.
Choose UHMW for anything that slides, scrapes or gets hit: wear strips, chain guides, chute and hopper liners, bumpers. Choose HDPE when you need to weld or thermoform it, want a lower price, or the part doesn't see much wear: cutting boards, tanks, marine panels, signs and fabricated assemblies.
The short version
UHMW (ultra-high-molecular-weight polyethylene) and HDPE (high-density polyethylene) look and feel almost identical on the shelf. The difference is the length of the polymer chains. UHMW's are roughly ten times longer, which makes it dramatically tougher and more wear resistant, but also harder to process. HDPE is the more versatile, lower-cost workhorse.
| UHMW | HDPE | |
|---|---|---|
| Abrasion resistance | Excellent (among the best of any plastic) | Good |
| Impact resistance | Excellent, even when cold | Good |
| Coefficient of friction | Very low, self-lubricating | Low |
| Stiffness | Lower | Slightly higher |
| Weldable / thermoformable | No (not practically) | Yes, both |
| Max service temp | ~180°F (82°C) | ~180°F (82°C) |
| Chemical resistance | Excellent | Excellent |
| Density | ~0.93 g/cm³ (floats) | ~0.95 g/cm³ (floats) |
| Relative cost | $$ | $ |
Typical values. Grades, fillers and suppliers vary; confirm with the datasheet for your grade.
Wear and impact: UHMW's whole reason to exist
UHMW is the material of choice anywhere something rubs, slides or gets battered: conveyor wear strips and chain guides, chute and truck-bed liners, dock fenders, star wheels and scraper blades. It outlasts HDPE by a wide margin in abrasion and keeps its toughness in freezing temperatures, where many plastics turn brittle.
Its slippery, self-lubricating surface also means bulk materials like grain, coal, wood chips and wet sludge flow off it instead of sticking.
Fabrication: where HDPE wins
HDPE melts and flows, so it can be extrusion-welded, butt-fused, thermoformed and injection molded. That makes it the go-to for tanks, sumps, ducting, boxes, and any fabricated assembly with welded seams. UHMW essentially doesn't flow when melted, so it's machined or cut from sheet and rod and assembled with fasteners.
Both machine and route easily, and both are sold in sheet, rod and cut-to-size blanks. See plastic welding shops for welded HDPE work and cut-to-size suppliers for blanks.
Heat and thermal expansion
Both top out around 180°F for continuous use and both expand a lot with temperature, roughly 10 to 15 times as much as steel. On long wear strips and liners, use slotted holes and leave expansion gaps, or the part will buckle on a hot day.
Cost
HDPE is generally the cheaper of the two and is widely available in colors, textured cutting-board grades and marine-board (UV-stabilized) grades. UHMW costs more, but in a wear application it usually pays for itself through longer life.
When to choose each
Choose UHMW for
- Wear strips, chain and belt guides
- Chute, hopper and truck-bed liners
- Bumpers, fenders and impact pads
- Star wheels, scrapers and guides on food lines
- Cold-weather and outdoor impact parts
Choose HDPE for
- Cutting boards and food-prep surfaces
- Welded tanks, sumps and duct
- Marine panels and outdoor furniture (UV grades)
- Signs, playground panels and machine guards
- Lower-cost parts with light or no wear
Tip from the counter: if a customer is replacing worn-out HDPE wear strips every few months, switching to UHMW (or a filled, self-lubricating UHMW grade) is one of the easiest upgrades in the plant.
Common questions
Which is stronger, HDPE or UHMW?
It depends on what you mean by strong. HDPE is slightly stiffer and has similar or slightly higher tensile strength. UHMW is far tougher: it has much better impact resistance (standard notched Izod tests don't break it) and several times the abrasion resistance. For parts that get hit, scraped or slid against, UHMW is the stronger choice.
What is the difference between UHMW and HDPE?
Molecular weight. Both are polyethylene, but UHMW's molecular chains are roughly 10 times longer (typically 3 to 6 million g/mol vs. a few hundred thousand for HDPE). Those long chains give UHMW its wear and impact resistance, but they also mean it can't be injection molded or easily welded.
Can you weld UHMW?
Not reliably with standard plastic welding. UHMW doesn't flow when melted, so hot-air and extrusion welds are weak. Join UHMW mechanically (countersunk screws, slotted holes) instead. HDPE welds very well, which is why tanks, ducts and fabricated assemblies use HDPE.
What is the disadvantage of HDPE?
HDPE wears faster than UHMW and is less impact resistant, especially in the cold. Like all polyethylene it has high thermal expansion, a modest heat limit (around 180°F), low stiffness compared with engineering plastics, and it's hard to bond with adhesives.
Is UHMW food safe?
Natural (white) UHMW and HDPE are both available in FDA-compliant grades and are widely used in food processing. Colored and reprocessed grades may not be. Ask your supplier for a compliance letter for the specific grade.
Values in this guide are typical figures for common unfilled grades, for general comparison only. Properties vary by manufacturer, grade, filler, and shape. Before you specify, buy or machine a material for an application, check the manufacturer's datasheet and the material certifications for the exact grade you're getting, and confirm suitability with your supplier.
Who stocks and machines it
Distributors that stock these materials and shops that machine or fabricate them, from the Stock & Shape directory.
UHMW
- Calsak Plastics – Tucson Tucson, AZ
- Laird Plastics – Detroit Shelby Township, MI
- Piedmont Plastics – Dallas Grand Prairie, TX
- Total Plastics – Indianapolis Indianapolis, IN
- CGR Products – Greensboro Greensboro, NC
- Hi Rel Plastics & Molding Riverside, CA
- K&E Plastics Bennington, VT
- Portland Precision Manufacturing Portland, OR
HDPE
- Curbell Plastics – Dallas-Fort Worth Arlington, TX
- Laird Plastics – Columbus Columbus, OH
- Multi-Craft Plastics – Portland Tigard, OR
- Piedmont Plastics – Westchester Thornwood, NY
- Alpha Plastics Solutions Muskego, WI
- H&S Machine Salt Lake City, UT
- Insulfab Plastics – Spartanburg Spartanburg, SC
- Zober Industries Croydon, PA