A plastic idler costs a fraction of a steel roller, needs no lubrication, and if it seizes it skids instead of cutting the belt. Conveyors & Bulk Handling duty is slow speed, abrasive dust and frame misalignment; the material is what decides whether the bearing survives it.
| Industry duty | slow rotation under steady belt pull, with abrasive dust at the load point |
|---|---|
| Typical media | abrasive dust, fines, washdown water |
| Housing temperature | −20 to +90 °C |
| Material and grade | PA66 nylon |
| Hardness | — (polymer, 75 Shore D) |
| Temperature ceiling | 105 °C |
| Corrosion / chemical | oils and greases; swells in water |
| Relative cost | 0.15× a steel bearing of a standard 52100 bearing |
On a parcel or tray conveyor the idler exists to reduce friction, not to carry load, and a steel bearing with a grease cavity is over-specified in every direction. A moulded PA66 roller with an integral bush is lighter, cheaper, quieter and cannot rust — and its failure mode is benign, since a seized plastic idler skids under the tray rather than machining the belt.
| Position | Bearing type | Material / finish | Why it works there |
|---|---|---|---|
| Light idler roller | PA66 roller | PA66 bush on a stainless axle | Cheap, quiet; a seized idler skids instead of cutting the belt. |
| Belt edge guide | PA66 roller | PA66 roller with a PA66 bush | No lubrication point and no rust stain on the product. |
| Guide rail slide | PA66 slide strip | PA66 slide strip | Low friction against an aluminium extrusion. |
| Material | Fit here | Choose it when |
|---|---|---|
| PA66 | Best fit | Light unit handling, low load, no lubrication point. |
| POM | Workable alternative | Higher stiffness and lower moisture pick-up for a precision guide. |
| 100Cr6 / 52100 | Workable alternative | Bulk material, hot product or heavy loads, where a plastic idler would collapse. |
Around 300 N per roller for a PA66 bush at low speed. Above that, the bush ovalises and the roller starts to wobble.
Yes, and better than steel in some ways — no lubricant to thicken. But PA66 gets brittle below −30 °C, so check the grade.
Moisture growth closes the clearance, or the axle rusts and grips the bush. A stainless axle and 0.2 mm clearance prevent both.
Hardness, temperature, corrosion and equivalents for PA66 nylon.
Read →Typical duty, recommended types and suffixes for conveyors.
Read →Head & tail pulleys — head and tail pulley bearings and idler positions in bulk handling.
Read →Washdown food conveyors — food-grade conveyors cleaned with water and caustic every shift.
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.