Chain conveyors fail at the pin and the sprocket, not at the slat. The pin wears because it is dry or because the load is too high; the sprocket wears because the chain is too tight or misaligned. Both are maintenance decisions.
Key takeaways
- Lubricate by interval and by condition, not only by calendar.
- Use the right lubricant for the temperature and the environment.
- Measure sag, not “feel”, when tensioning.
- Replace the chain when the wear exceeds the sprocket tolerance, not when it breaks.
Lubrication intervals
For a clean, room-temperature conveyor running one shift, lubricate every 200–300 hours. For a three-shift line, every 100–150 hours. For a hot oven conveyor, use a high-temperature lubricant and inspect weekly; some oven chains run dry with a graphite coating.
These are starting points. The actual interval should be based on inspection: if the chain is dry or the lubricant is contaminated, shorten the interval.
Lubricant selection
Use a chain lubricant that penetrates the pin and bushing, not a grease that sits on the surface. For food areas, use a food-grade lubricant. For high temperature, use a synthetic lubricant rated for the oven temperature, or a dry-film lubricant.
Do not mix lubricants with different bases. A mineral oil and a synthetic oil can separate and leave the chain dry.
| Environment | Lubricant | Interval |
|---|---|---|
| Clean, indoor | Mineral chain oil | 200–300 h |
| Dusty | Dry-film or graphite | Weekly inspect |
| Food area | Food-grade oil | Per hygiene plan |
| Oven, <200 °C | Synthetic high-temp oil | 100–150 h |
| Oven, >200 °C | Dry-film graphite | Per manufacturer |
Tensioning
Measure the sag on the return run at the midpoint between the sprockets. A sag of 1–2% of the centre distance is a reasonable target for most conveyors. Use a straight edge and a ruler, not hand pressure.
Adjust the take-up evenly on both sides. A take-up that is adjusted on one side only will misalign the chain and wear the sprocket. After adjustment, run the conveyor for 10 minutes and re-measure.
Wear judgement
Check the chain for elongation, worn rollers, cracked plates and tight joints. Elongation above 1.5–2% of the original length is usually the replacement limit. A chain that has elongated will not mesh correctly with the sprocket and will wear it rapidly.
Check the sprocket teeth for hooking or sharpening. A worn sprocket will wear a new chain quickly; replace the chain and the sprocket together if both are worn.
Cleaning and contamination
Clean the chain before lubricating. Dirt mixed with oil forms an abrasive paste. Use a brush or a low-pressure cleaner, and dry the chain before applying lubricant.
In food areas, use a cleaning procedure that is compatible with the lubricant. A lubricant that is washed away by the cleaning chemical is not protecting the chain.
Frequently asked questions
How often should a conveyor chain be replaced?
When elongation exceeds 1.5–2%, or when the chain has tight joints or cracked plates. The interval depends on load, lubrication and environment.
Can I use grease instead of oil?
Grease is better for slow, heavily loaded chains, but it does not penetrate the pin as well as oil. For conveyor chains, oil is usually preferred.
Why does the chain wear on one side?
Usually misalignment or a take-up that is tighter on one side. Check the sprocket alignment and the take-up positions.
For the daily checks that support this work, see the 12-point inspection.
