Nylon vs Acetal vs PTFE vs UHMWPE: choosing an engineering plastic
Engineering plastics replace metal where friction, weight, corrosion or noise is the problem — but the right grade depends on how the part is loaded and where it runs. This is a practical comparison of the materials we machine and mould most often, to help you specify the right one on your drawing.
At a glance
| Material | Strengths | Choose it when |
|---|---|---|
| Nylon (PA6 / PA66) | Tough, wear-resistant, good strength-to-weight | Load and abrasion together — gears, bushes, rollers. Absorbs moisture, so allow for dimensional change in wet or humid service. |
| Cast Nylon | Higher stiffness and dimensional stability; large sections | Large gears, wear pads and sheaves machined from thick stock. |
| Acetal / POM (Delrin) | Low friction, dimensionally stable, excellent machinability | Precision moving parts that must hold tolerance. Low moisture pickup; avoid strong acids. |
| UHMWPE | Extreme abrasion resistance, low friction, non-stick | Sliding contact or abrasive flow — chute liners, guide rails, wear strips. Low stiffness; not for high heat. |
| HDPE | Food-compatible, chemically inert, cleans readily | Food-contact guides and surfaces where strength demands are modest. |
| PTFE | Lowest friction, widest chemical and temperature range | Sealing and low-friction duty. Soft and creeps under load — often glass-, carbon- or bronze-filled for wear. |
| PEEK | High temperature, high load, chemically aggressive service | The most demanding environments, where cost is justified by performance. |
Nylon (PA6 / PA66) — the general-purpose workhorse
Nylon is tough and wear-resistant with a good strength-to-weight ratio, which makes it the default where load and abrasion occur together — spur gears, bushes and industrial rollers. Its one caveat is moisture: nylon absorbs water and moves dimensionally with it, so in wet or humid duty you either allow for the change or move to a more stable material. Cast nylon adds stiffness and stability and comes in larger sections for big gears and wear pads.
Acetal / POM (Delrin) — precision that holds tolerance
Acetal is dimensionally stable with low friction and excellent machinability, and it barely absorbs moisture — so it holds tolerance in continuously moving parts far better than nylon. Reach for it on precise small gears, cams and snap-fit features. It is not the choice for strong-acid environments.
UHMWPE — abrasion and sliding wear
Ultra-high-molecular-weight polyethylene has outstanding abrasion resistance, a low coefficient of friction and a non-stick surface, so it performs where sliding contact or abrasive flow would wear other materials — chute liners, guide rails and wear strips. It is relatively low in stiffness and not suited to high temperatures.
PTFE and PEEK — chemical, thermal and low-friction duty
PTFE offers the lowest friction and the widest chemical and temperature range of the common polymers, which suits seals and low-friction bearings — but it is soft and creeps under load, so it is frequently filled with glass, carbon or bronze for wear applications. PEEK is the high-performance option for high temperature, high load and chemically aggressive environments, where its cost is justified by the duty. For food-contact parts, HDPE is impact-resistant, chemically inert and cleans readily.
Head-to-head comparisons
Most material decisions come down to two candidates. These are the pairings we are asked about most often.
Acetal vs PTFE
Acetal is the stronger, stiffer material and holds tight tolerance, so it suits gears, bushes and precise moving parts under load. PTFE has far lower friction and survives heat and chemicals that acetal cannot, but it is soft and creeps — choose it for seals, seats and chemical duty, or a filled grade where it must also resist wear. Read the full Acetal vs PTFE comparison →
Acetal vs UHMW
Acetal wins on stiffness and precision; UHMWPE wins on abrasion and impact. For a part that must hold dimension, specify acetal. For a liner, guide or wear strip that product slides or rubs against, specify UHMWPE. Read the full Acetal vs UHMW comparison →
PTFE vs UHMW
Both slide easily. PTFE handles temperature and chemicals that UHMWPE cannot and has the lowest friction of all, but wears quickly unless filled. UHMWPE is far more abrasion- and impact-resistant and costs less, within a service range that tops out at around 80 °C. Read the full PTFE vs UHMW comparison →
Nylon vs Acetal
Nylon is tougher and copes better with shock load and heavier abrasion; acetal is more dimensionally stable because it absorbs very little moisture. In wet or humid service, or where the tolerance is tight, acetal is usually the safer specification. For larger gears and rollers that take knocks, nylon or cast nylon is the usual choice.
Related comparisons
Final material suitability depends on the component drawing, load, speed, operating temperature, chemical exposure, food-contact requirements, wear conditions and validation. Tell us the position the part runs in and we will manufacture to the grade your drawing specifies — or discuss the material if the drawing leaves it open. See the full materials list for designations and characteristics.
Not sure which grade suits your part? Send the drawing and we’ll advise.
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