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Many maintenance organizations face similar challenges concerning asset failures, and they usually follow the same pattern when dealing with them. That is, quickly correcting the failure, then identifying the cause, and determining how to mitigate future breakdowns of that type.
The causes of asset failures often fall into one of several major groups which must then be further analyzed to determine the possible root cause. We’re going to identify some of the major classes of failures and ask you to consider how you identify and address the most common sources of breakdowns in your maintenance operations.
Research shows that the following five categories of asset failure are prevalent in most asset intensive industries. Of course, your experience may be different from what we have found. These categories and possible remedies are not presented in any particular order of importance but represent common failure causes experienced by maintenance organizations.
It’s important to note that some asset failures may be due to a combination of more than one category. A thorough investigation of all breakdowns should be undertaken before pointing a finger at any one possible cause.
1. Undermaintaining
Undermaintaining of equipment includes both deferred maintenance and not adequately maintaining all the right “points” on equipment. It may also speak to insufficient planned maintenance frequency which does not address the actual maintenance demands of the equipment.
The virtues of preventive maintenance have been well established with lower cost, improved asset availability (uptime), and increased safety leading the list of benefits.
Signs of undermaintaining may be frequent production stoppages, a reduction in throughput, or degraded product quality. These indicators may not all be attributed to undermaintaining, but it is a possibility that should be investigated.
A thoughtfully planned, scheduled, and well-executed preventive maintenance program should support the maintenance demands of the assets. Meticulous planning of labor, spare parts, tools, and equipment should ensure that maintenance work can be accomplished as scheduled.
Reliability programs can support adjustments to the maintenance intervals through periodic inspections and condition-based monitoring so that future maintenance events become scheduled based on asset needs, not just predetermined time intervals.
2. Over Maintaining
Most preventive maintenance schedules are based on set time intervals or a given number of run cycles. Blindly following a preset schedule can lead to under or over maintaining your assets. Both conditions can arise when we’re not determining the asset’s actual maintenance needs, and both conditions can lead to asset failure.
Can you really perform too much maintenance? Absolutely! Most maintenance events require the asset to be out of use. The more maintenance events you have scheduled, the less uptime is available.
All work has a cost. Replacing perfectly good components is an unnecessary labor and material expense. Repeated disassembly and reassembly can cause excessive wear on components or skew precision alignments. For this reason and others, maintaining too often can actually increase the risk of breakdown.
The first step in dealing with over maintenance is determining if it’s a systemic problem or if it’s restricted to a few individual assets. This defines the scope of the conversation you’ll have with the maintenance planners.
The focus of that conversation is the strategy they’re using for planned maintenance intervals. Was this strategy recommended by the manufacturer, inherited from the previous job holder, or are there other reasons why the interval is set the way it is?
Analyze the removed maintenance parts, materials, lubricants, etc. to determine the remaining life of these components. If little or no wear is detected, then you need to ask why the items were replaced.
You could consider a reliability program for any assets in question. Maintaining based upon current conditions requires inspections or condition monitoring, but should result in less maintenance if you are currently over-maintaining your assets.
Looking into this may also yield other benefits, as you may discover maintenance points which should be added to the plan, or points which could be discontinued.
3. Design flaws
Let’s face it: some failures and repeated breakdowns are inherent in the equipment design or manufacturer’s choice of components. The manufacturer sets the recommended schedule for maintenance based upon their engineering specifications, yet you may find that the effort and cost required to maintain production quality and/or uptime is unacceptable.
The vendor – customer relationship is critical in these situations to ensure that both parties are fully committed to reducing breakdowns caused by design flaws.
Make full use of any existing warranty agreements to resolve design issues. Just remember that your company may have responsibility for conducting all required maintenance and submitting warranty breakdown claims to the supplier in a timely fashion or you risk voiding the warranty.
Tracking every single warranty and all of their requirements can be tough, especially if you’re trying to do it with a spreadsheet. As an aside, Prometheus Group’s Warranty Tracker can help turn warranty management from an onerous burden into a profit center that boosts your bottom line.
In a perfect world, collaboration with the asset manufacturer should result in design changes which improve reliability. However, doing that may mean expending a significant amount of your company’s engineering resources.
In extreme situations, other avenues such as vendor contract renegotiations or legal actions, may be required if design attributed breakdowns cannot be resolved.
4. Metal Fatigue and Corrosion
These are factors working against you by constantly undermining the serviceable state of your assets. Metal fatigue is the weakening of a material caused by cyclic loading that results in progressive and localized structural damage and the growth of cracks. In simpler terms, metal breaks when you bend it too much.
Metal fatigue can go undetected until a breakdown occurs. The results may be catastrophic from both a serviceability and safety standpoint.
Corrosion can attack exposed and unexposed surfaces and cause deterioration in the affected material. Corrosion may be the result of exposure to weather, moisture, heat, chemicals, and other factors which can lead to material fatigue and eventual material failure.
Both of these involve damage to metal components, but the causes and impacts can be quite different. I will address the differences individually below.
Metal Fatigue
Metal fatigue is often more difficult to detect than corrosion. However, dyes and fluoroscopes are one accepted method used on assemblies where cracks are found, or suspected, to determine their size and “growth” over time.
The correction plan can be very complicated. This is because actually correcting the underlying issue, rather than simply replacing worn components, means making sure the metal fatigue doesn’t arise in the first place. This will likely require substantial engineering to assure a safe and effective rectification.
Corrosion
Corrosion can often be found through visual inspections. The first step is to identify and inspect the likely points where corrosion may occur. This can be accomplished through planned maintenance activities and periodic visual inspections.
When the first signs of corrosion appear, deal with it! Identify the cause and correct it by repairing, resurfacing, or replacing the affected materials. You should also seek to identify ways to prevent the corrosion from occurring in the first place, but frankly that isn’t always possible.
5. Improper Operation
Operators wield tremendous influence over the effective operation of production equipment and its maintainability. They can run assets outside of the manufacturer’s specifications, incorrectly adjust critical production processes, load materials improperly, and control a multitude of other variables which affect production throughput, product quality, machine condition, and ultimately maintainability.
Many asset failure incidents arising from improper operation may be attributed to a lack of training. Employees new to a machine, and given little or no instruction, should not be expected to precisely run critical production assets. Also, the risk of safety incidents is high in situations where inadequate training has been received.
While most employees have had previous operator training, processes may have changed, or procedures may have been adjusted over time and have become standard practice. A review of operator skill levels and current operating procedures should be conducted periodically.
This should help determine if operator retraining is necessary. Training materials should be updated to reflect current operating procedures and instructions.
In some companies, operators are responsible for managing lubrication and keeping their machines free of dirt and debris. Involving operators in maintenance activities promotes cooperation between maintenance and operations.
Experienced operators know when a machine does not “sound or feel right” and a close relationship with maintenance can help catch maintenance issues before breakdowns occur.
Most improper operation failures can be avoided by assuring that employees receive proper operating instructions and guidance. Operator training should be a pivotal element of your reliability program. Always remember that other failure factors could be contributing factors to breakdowns and so it should not be assumed that operator error is the only cause.
Preventive maintenance programs are intended to keep machines performing in peak condition by detecting wear, and other potential failure indicators, at a point before component or asset breakdown occurs. Both too much maintenance and too little can have negative impacts on cost, safety, and reliability.
Prevent Asset Failure Through Well Designed Asset Maintenance Strategies
Some precursors to failure, such as corrosion and metal fatigue, are not always readily apparent. Others, such as design flaws and improper operation are not really within the control of the maintenance team.
While a breakdown may seem to have one primary cause, careful analysis will likely expose additional factors that contributed to the failure.
Reliability strategies, which includes operator training, should be supported by well executed predictive and preventive maintenance programs to reduce the likelihood of future asset failure.
Scheduling and planning of maintenance activities lies at the heart of any solid maintenance program. Contact Prometheus Group to see how we can help you with planning, scheduling, and every stage of the maintenance workflow.
