When a gear strips, a bushing squeaks or a slide wears through, the fix is usually the material, not the design. Often the base resin is fine and the filler package is what needs to change.
Why plastic parts wear
- Load and speed together (often called PV, pressure × velocity). Friction turns into heat, and plastics don’t move heat away well, so the wear zone softens.
- The mating surface. Rough or abrasive counterfaces, and glass-filled plastic running against itself, speed up wear.
- Environment. Moisture swells nylon and changes its clearances; chemicals and heat attack some resins.
- Lubrication, or the lack of it.
Start with the base resin
Acetal, nylon, polyketone, PBT, UHMW polyethylene and PEEK are the usual wear materials. Acetal and polyketone hold dimensions better than nylon in wet conditions; nylon is tough and economical; PEEK handles heat the others can’t. See acetal, nylon and polyketone.
What each filler does
| Filler | What it does | Watch out for |
|---|---|---|
| Carbon fiber | Adds stiffness and strength, pulls heat out of the wear zone, lowers wear, and can make the part static-dissipative. | Cost; properties differ along and across the flow; black only. |
| Glass fiber | Adds strength and stiffness at low cost. | Abrasive. It can wear out the mating part. |
| PTFE | Lowers friction; reduces squeak and stick-slip. | Lowers strength; adds cost. |
| Silicone | Lowers friction, especially at start-up. | Can migrate to the surface; may affect painting or bonding. |
| Graphite / MoS₂ | Lowers friction; common in nylon. | Limits color to black or gray. |
| Aramid fiber | Resists wear and is gentle on the mating surface. | Cost; harder to process. |
A quick way to choose
- Part deflects, runs hot or wears fast under load: carbon fiber.
- Squeaks or sticks: PTFE or silicone.
- The mating part is getting chewed up: move away from glass and toward PTFE or aramid.
- Wet environment: consider acetal or polyketone over nylon.
What we supply
We supply carbon-filled nylon 6, nylon 66 and polypropylene. Other base resins and filler packages depend on availability, so ask. Carbon-filled nylon & PP →