How to avoid pin bushing wear and minimize repair costs

THE EFFECT OF CONTAMINATION

The effect of contamination on pin bushings is a direct result of scaring, skidding/ploughing and smearing. Excessive contamination build-up between a pin and bushing surface restricts the pin’s movement by increasing friction.
 

^{Open lube points that lack fresh grease allow dirt to easily enter the system.}

Without a solution, the increasing friction and load pressure lead to the pin gouging the bronze, eroding the bushing’s material so it can keep rotating. The material deposits then cause a vicious cycle of continued contamination and wear. When all the bronze bushing material is worn away, the pin will start digging into the steel structure of the equipment. 

Wear evolution due to contamination:

1. Good bushing
2. Worn bushing
3. Worn bushing affecting the frame

A worn bushing may need replacing, which means production machinery is generally put out of service.

• If only the bushing is damaged, the pin and bushing set may need to be replaced.
• If the structural steel of the equipment is damaged, you will probably need a ‘line bore’, increasing costs exponentially.
   

Cost of bushing pin repairs

Replacing a damaged pin/bushing can cost up to $1, 500 and is quite time-consuming, as your equipment may need to be moved to an off-site workshop. A “simple” replacement of worn parts lasts between 5 to 8 hours if the pin/bushing is not stuck.
 

When a worn pin has damaged the equipment's structural steel, you are faced with replacement costs, additional downtime, repair costs for line boring ($500 per hole), welding, and refitting
 

The importance of proper lubrication maintenance

Proper lubrication can significantly reduce the need for replacement or repair of pin bushings. Most pin bushings have ‘grease grooves’ on the inner diameter where applied lubricants form a thick film for the pin to rotate on.
 

These lubricants also help to “purge” contaminants from the bushing by forcing out unwanted materials. However, if these grooves aren’t lubricated (and purged) on time, they become home to contamination – resulting in wear.
 

Automatic lubrication minimizes damage and costs

Automatic lubrication systems consistently dispense accurate doses of lubricant while the system is working. Therefore, the entire pin is coated and the circumference is purged thoroughly.
 

A well-lubricated pin increases equipment life extends machine performance and reduces the maintenance- and repair frequency. That leads to minimal downtime, preventing loss of revenue.