The Issue

Dipper door not opening and closing efficiently with the trip rope wedge and socket breaking frequently. Failure rate was found to be an average 12 per month, creating excessive downtime of 18.25 hours.

The Impact

  • Failure rate an average of 12 per month
  • 83 breakdowns over the financial year
  • 257 hours of downtime over the financial year (approx. 21 hours per month)
  • At a downtime cost of $15,000 per hour for the electric shovel, the total cost of dipper breakdown for the financial year was approx. $3.8million

The Investigation

Our investigation into the dipper bucket issue established the following:

  • The dipper door was not opening because to the latch bar and dutch man were disengaging
  • Too much play of the latch bar within the box made closing and opening the door harder
  • The wear out of dutch man allowed the engagement area to be out of spec, also contributing to open and closing problems
  • Latch lever path was out of alignment causing steel drag, friction and wear
  • High motor torque led to the breakage of the anchor bracket as the lever smashed the anchor bracket upon the disengagement

The Solution

  • Wear liner kit for the latch bar tunnel to reduce the movement of the latch bar
  • Two strengthening brace on the door to maintain latch lever alignment
  • Wear liners installed on the lever guide plates

The Advantages of a Wear Liner Kit

  • Easy to install resulting in reduced downtime
  • Material is not high-wearing and this would not need frequent change outs
  • The wear lines are not heavy to handle and as a result reduce the risk associated with material handling
  • AustLon® (PA6 G) material used has a low co-efficient function and thus allows the latch bar and the lever to move freely within the box and guide plates respectively

The Outcome

  • Reduced downtime per month from 21 hours to 2 hours per month due to adjustment (not failure)
  • At a downtime cost of $15,000 per hour for the electric shovel, the total saved over a financial year is projected to be
  • Our solution saved BHP Billion $3.4 million over the financial year (based on the reduced downtime and an hourly downtime cost of $15,000 per hour)

This case study exemplifies how critical it is to select the right material for your component. The correct choice will not only have a positive impact on the rate of productivity and the working environment, but also on the overall profitability of your business.

When material has such an impact, it’s important to work with a manufacturer who can provide you with the expertise and support you deserve so you can make the best decision for your business.