Roller chain is a precision made item that is manufactured to very tight tolerances.
When it is first manufactured, the chain can be wrapped around the sprocket and the rollers will fit perfectly into the seating radius of the sprocket.
With repeated use, however, roller chain will elongate due to wear.
The extent of roller chain wear will be determined by:
- The type of chain application
- The loads being exerted on the chain
- The lubrication used
- The maintenance regime employed.
As roller chain elongates, the individual rollers will start to contact the flanks of the sprocket teeth rather than fitting perfectly into the seating radius.
This is a gradual process that can lead to several unwanted roller chain problems.
- As the roller chain rollers contact the flanks of the sprocket teeth under load, the impact will cause these surfaces to become worn. This will gradually result in ‘hooked’ sprocket teeth, which will then lead to total failure of the sprocket teeth.
- The roller chain application will become increasingly more noisy and inefficient. Ignoring the noise of a badly worn roller chain setup is one thing but, as the efficiency of the roller chain drive diminishes, the costs associated with running the system will inevitably rise.
- An increasing amount of vibration within the chain setup can lead to problems with other associated equipment.
When roller chain is being used in pairs for conveying, or singularly for an indexing application, any significant amount of roller chain wear can lead to mismatch or misalignment which can result in bigger problems with any associated equipment.
By measuring roller chain for wear at regular intervals with a chain gauge, the amount of increase in length can be predicted and the roller chain can be routinely scheduled for replacement.