Below about 1,000 rpm and 300 N, a POM bearing is quieter than steel, needs no grease and costs a fifth as much. It is the right answer for a fan tray, and the wrong one for a belt-driven shaft. Fans, Blowers & HVAC duty is light load, condensation during shutdown and noise limits; the material is what decides whether the bearing survives it.
| Industry duty | light load from unbalance and belt pull, a few hundred to 3,000 rpm |
|---|---|
| Typical media | dust, lint, condensate, pool and food washdown |
| Housing temperature | −20 to +80 °C |
| Material and grade | POM acetal polymer |
| Hardness | — (polymer, 80 Shore D) |
| Temperature ceiling | 90 °C |
| Corrosion / chemical | water and weak chemicals; attacked by strong acids |
| Relative cost | 0.2× a steel bearing of a standard 52100 bearing |
A steel ball bearing in a small fan is over-specified in every direction except life: the load is a few tens of newtons, the speed is low, and the noise of the balls is louder than the air. POM replaces the whole grease-and-seal problem with a plain bearing running on a stainless or hardened shaft, and its damping removes the tonal noise that makes small fans objectionable.
| Position | Bearing type | Material / finish | Why it works there |
|---|---|---|---|
| Axial fan hub | Plain POM bearing | POM radial bearing, dry | No grease to leak or dry out; quiet below 1,000 rpm. |
| Appliance blower | POM bush | POM bush on a stainless sleeve | Tolerates the humidity cycle of a fridge or dryer better than nylon. |
| Damper and louvre pivot | POM bush | POM bush, 0.1 mm clearance | Low friction without lubrication in a dusty air stream. |
| Material | Fit here | Choose it when |
|---|---|---|
| POM | Best fit | Light axial fans, fan trays and appliance blowers below 90 °C. |
| PA66 | Workable alternative | Higher toughness and a 105 °C ceiling, but it swells in humid air and the clearance has to be opened up. |
| Bronze | Workable alternative | Sintered bronze bush where shaft speed or load exceeds what POM can take. |
No rolling elements and no metal-to-metal contact, and the polymer damps vibration instead of transmitting it. That removes the tonal noise at the ball pass frequency.
In a small fan, yes, for a while — but the PV limit is being approached. Above about 2,000 rpm a bronze or a small ball bearing is safer.
No, and adding grease usually makes it worse: the grease attracts dust and the polymer does not need the film.
Hardness, temperature, corrosion and equivalents for POM acetal.
Read →Typical duty, recommended types and suffixes for fans & hvac.
Read →Standard fan duty — fan and blower shafts in air handling units, cooling towers and roof extract fans.
Read →Coastal & pool plant — roof extract fans, cooling tower fans and pool plant blowers in salt or chlorinated air.
Read →Send the position, bore size, quantity and the medium it sees. We reply with the material certificate, clearance class, lubricant and price within 30 minutes on working days.