Are you giving your maintainers the information and resources they need to do their jobs effectively?
An effective maintenance work management process must set maintainers up for success. If the service sheets and procedures they need to follow for quality work execution aren’t crystal clear, then variations in technique and process allows defects and discrepancies – which might seem minor at the time – to creep in.
Bluefield recently conducted a study into chronic defects at a site running off highway trucks. We found one of the top defects was A-frame failures.
At the time of our site visit, there were two trucks in for unscheduled A-frame bearing or frame replacements. Apart from the production loss arising from the downtime, this task is relatively labour-intensive, so resources were being pulled from other preventative tasks to repair the unscheduled failures. One of these events resulted in approximately five days of downtime. More importantly, breaking a machine in two to conduct repairs is also a high-risk task.
We sought and reviewed service sheets leading up to the failure dates, making the following observations with respect to work execution quality:
- In the approximately 6 months leading up to the failures, several events occurred which may have provided early indications a component failure was underway.
- Lubrication system inspections had been checked off on service sheets, with only one corrective notification raised from them (very late in the timeframe).
- The failure modes of the trucks could easily lead to an assessment of lack of lubricant being a contributing factor.
We also noted that in the A-frame service inspections of both machines, measurement of movement against specification appeared to vary over time. There were instances of the measurements being out of specification, but then being back within specification next service. This, it would seem, is impossible if a standard measurement methodology is used.
Our other observation was the measurement parameters changed over the timeframe of the data collection. On one service sheet, measurements were to be taken in imperial, the next service sheet was to be recorded in metric and in a third, the maintainer was given a choice. The output was confusing data to base any corrective decision upon.
Post-investigation discussions with maintainers also provided insight into the variation in techniques used to complete the service sheet inspection.
Some maintainers were of the opinion it was a very difficult task while others saw it as very straight forward if the correct technique was used.
A key aspect of the maintenance work management process is to analyse its effectiveness regularly so you can improve. Sites need to have a process for updating service sheets and for it to be swift and simple. Lack of action on rectifying an incorrect service sheet will surely lead to lack of action on a maintainer’s part in continuing to report the problem.
If the correct people are not routinely reviewing completed service sheets (ie planners and reliability engineers), then “free kicks” or points of detection are missed, and the result is often in expensive failures.
By John Thomsen