Noise is the easiest symptom to notice and one of the hardest to diagnose. The source is not always where the sound appears to come from. The six sources below cover most conveyor noise complaints.
Key takeaways
- Identify whether the noise is continuous, periodic or load-dependent.
- Use a smartphone sound meter or a stethoscope to locate the source.
- Fix the cause, not the symptom; a rubber pad is not a repair.
- Check the structure for resonance before replacing components.
1. Bearings
A dry or worn bearing produces a continuous grinding or rumbling sound that increases with speed. It may be localized to one roller or one drive. Touch the bearing housing; a hot bearing is a failing bearing. Replace it before it seizes.
2. Chain
A dry chain produces a metallic rattle; a tight chain produces a whine; a worn chain produces a clicking at the sprocket. Check the lubrication, the tension and the sprocket wear. A chain that is too tight will also load the bearings.
3. Belt
A belt that is misaligned produces a rhythmic slap or squeal. A belt with a bad splice produces a thump once per revolution. Check the tracking, the splice and the pulley condition. A belt that is too tight will whine.
| Noise | Pattern | Likely source |
|---|---|---|
| Grinding | Continuous | Bearing |
| Rattle | Continuous, dry | Chain lubrication |
| Whine | Speed-dependent | Tight chain or belt |
| Thump | Once per revolution | Splice or bent roller |
| Squeal | Intermittent | Belt slip or misalignment |
| Hum | At one speed | Structural resonance |
4. Structure
A frame that is not rigid or not anchored can amplify noise. A conveyor on a mezzanine may excite the mezzanine structure. Check the anchors, the leg bracing and the connection to the building. A rubber isolation pad can help, but only after the structure is stiffened.
5. Drive
A gearbox with worn gears produces a whine that changes with load. A motor with a bad bearing produces a rumble. A VFD with a high carrier frequency can produce a high-pitched whine from the motor. Check the gearbox oil and the motor bearings, and adjust the carrier frequency if the whine is electrical.
6. Product
Product that is loose, vibrating or hitting a guide produces noise that is not the conveyor's fault. Check the product position, the guide clearance and the transfer. A product that is too light for the conveyor may bounce.
Diagnostic method
Run the conveyor empty and listen. Then run it loaded. If the noise is present empty, it is mechanical; if it appears only loaded, it is product or load-related. Use a stethoscope or a screwdriver to listen at the bearing housings, the gearbox and the frame. Compare the sound at different speeds.
If the noise appears at one speed only, suspect resonance. Change the speed slightly and see if the noise disappears. If it does, stiffen the structure or add a skip frequency in the VFD.
When to call for help
If the noise is accompanied by vibration, a current rise or a temperature rise, stop the line and inspect. A noise that is ignored can become a failure that damages the product or the conveyor.
Frequently asked questions
Is a noisy conveyor dangerous?
Not always, but it is a symptom. A noise that is new or increasing should be investigated.
Can I use rubber pads to reduce noise?
They can reduce structure-borne noise, but they do not fix a worn bearing or a misaligned belt. Fix the cause first.
How do I measure conveyor noise?
Use a sound level meter at 1 metre from the conveyor and at the operator position. Record the dB(A) and the operating condition.
For a structured inspection, see the 12-point daily check.
