Why do reliability improvement projects often only lead to short term improvement?
We have seen, over the years, that reliability performance of mining fleet improves but then degrades again, and we end up with a cycle of performance, like the availability results over 5 years, in the diagram below.
This type of cyclic result is caused by an approach to reliability improvement which is focussed on fixing the conditions on the equipment, but not addressing the maintenance “systems” or “acceptance of poor standards” that allow the equipment condition to degrade to a point where the unscheduled maintenance is out of control. We have even seen companies running what they call “jumpstart programs” or “campaigns” to improve poor equipment condition which is generating poor performance. This campaign approach usually comes at high cost and is not often budgeted as it requires the replacement of the equipment that has been allowed to deteriorate.
We recently saw an example of this where the site had a major problem with equipment lighting. That is, one of the top 5 causes of downtime was something as simple as lighting! The selected solution to this problem was to install new lights and at the same time the site chose to redesign how they were fitted to the machine. This created a short term improvement, as you would expect when all of the lights on all of the machines have been upgraded. Unfortunately, this causes a spike in costs and also will only be a temporary reprieve unless the underling problems are corrected. Some questions that must be asked before deciding on an engineering change are as follows:
- What are the failure mode/s causing the failures and have we attempted to control them in the past?
- Why have our efforts to manage these failure modes not been effective?
- Why have we not kept on top of the deteriorating conditions during our standard PM program?
- If the problem is new, what has changed since the original installation?
- Does the campaign solution address failure modes, that can not be managed without redesign, or just symptoms of poor maintenance?
If the design changes are warranted based on design problems and not just to address a lack of maintenance standards, and a campaign must be implemented then the following must also be asked:
- Are there any new failure modes that are being designed in with this change? e.g. by fitting the new light mounting arrangement with bolts that can come loose, rubbing of new wiring, etc.
- Do we need to add to the PM program (checklists) e.g. Something to check the bolts on the light mounting, especially if it is something that has to be removed for other maintenance activities?
- Do we need spares put into stock e.g. new lights, a mount for the new light if it can get damaged or broken
- Does the business case account for the cost of the design changes in the life of asset maintenance plan?
Often, the reality is, that redesign is not warranted. OEM’s do a lot of engineering work to ensure the product has a level of reliability suitable for the application. A thorough and deep root cause analysis of these types of poor reliability issues will find some or all of the following contributors:
- The maintenance strategy for the machine didn’t identify the failure mode and establish an acceptable standard.
- The maintenance strategy doesn’t identify the correct or complete parts list to help maintain the standard.
- The original machine configuration was not maintained, additional wiring joints, loose connections, loose mounting, incorrect or incomplete assembly etc.
- Inferior parts have been sourced through cost saving initiatives.
- Maintenance standards are not verified by the maintenance execution team.
When a reliability problem is encountered it is first necessary to correct the failures in the maintenance system that allowed the degradation of condition to such a level. A redesign or replacement campaign is a temporary fix at best, and a longer term reliability problem at worst. Overcoming the actual deficiencies in the system and standards is a simple process and delivers sustainable good performance.