I didn’t invent the phrase “Engineered Maintenance,” but I like to use it frequently. I’ve always said that if an individual would just read and follow the operations and maintenance manual and maintain that piece of machinery exactly as prescribed in that manual, there wouldn’t be any measurable downtime throughout the course of its usable life. This is merely a long-time theory of mine, but I’ve always tried to prove it by applying practical engineering concepts into everyday maintenance activities. I’ve always tried to find better ways to gain more optimization, availability and reliability in every segment of the maintenance activities. Below are a few things I’ve found that have made the largest impact in our maintenance activities through the years.
Reprinted with the permission of Equipment Manager magazine, the magazine of the Association of Equipment Management Professionals.
“Engineered Maintenance” is more than “extending maintenance intervals.” Most of the larger fleets operating today have incorporated extended maintenance into their maintenance profiles, but engineered maintenance goes beyond that. In its simplest form, it means ways in which the required maintenance will be performed, or completed quicker, easier or in the best-case scenarios, without that of human interaction.
As we all know, maintenance must occur or the rate of wear in or on a particular component will increase exponentially to the point that failure will be quick, inevitable and expensive. We also know that human intrusion during repair or maintenance activities can be our own worst enemy. With that in mind, I look at ways to satisfy both issues. Can we replace grease zerks with extended grease hoses? Can we route those grease hoses into a central location, making them easily acceptable and safe to grease? Can we place this group of hoses in a dustproof enclosure to eliminate the possibility of dirt egress into the system when its being greased? If we are going to that length, is it possible to incorporate an auto-lubrication system into the equation, with metered grease amounts specific to the load, rotation and application of each grease point? Maybe the answer is not to grease at all and find a bushing, bearing, shaft material or combination of materials that will handle the loads, wear and environment but doesn’t require lubrication. Maybe we can find a wear material that will align to the replacement criteria of the component, thus eliminating the need for maintenance in that area.
Today we are all extremely cognizant of the impact we have on the environment. Our owners and clients expect us to find more environmentally friendly procedures to help in this cause. There is a real challenge in finding a balance between proper maintenance and the risk associated with handling our machine fluids and lubricants. Extending oil drain intervals by way of oil sampling is an excellent way of mitigating this risk. The addition of additive packages at predefined cycle intervals can extend the useful life of some oils. Using off-line filtration or “scavenger circuits” is another way that large amounts of oil and fuel can be maintained and preserved. The cooling and consistency of the units’ oil temperature is another way to extend its useful life. I look specifically at the oil cooling circuits and try to find ways to maintain the oil in its optimal temperature range without a lot of cooling and heating cycles. On the extreme side, I’ve seen onboard particle counters being used in different applications that continuously monitor the fluid health in “real time.”
Jason Ruggles, above, has nearly 25 years experience in the heavy equipment and crane industry. He is currently the crane manager for Infrastructure & Energy Alternatives, LLC.
On the electrical side of our equipment, I look at ways to eliminate and reduce breakdowns and speed up the repairs when necessary. In doing this, one must start with the unit’s intended environment. Is it going into a harsh saltwater environment, freezing and cold climate, or in hot and dry desert-like areas? Each of these climates or conditions needs to be addressed separately. In a saltwater environment, for example, I ask our technicians to pull all the connectors and lubricate them with a dielectric grease to keep the salt air and water off the corrosion-susceptible pins and sockets. They use marine-grade terminals and heat shrink when making connections and/or repairs. We instruct them never to puncture a wire or harness when looking for a power failure or short-to-ground condition. This seemingly innocent act during troubleshooting is causing more harm than can be calculated at the time of the act due to the small holes being put in the wire jacket the length of the harness.
Inevitably, wiring must be routed in or through areas where it will be exposed to oil, grease, water, etc. In those areas, it’s best to look at the wire’s jacket or the outer covering of the wiring harness. Is it acceptable for those locations? Is it resistant to the conditions it will be exposed to? Many times, the correct jacket on a wiring harness can mitigate or reduce costly electrical issues. Look closely at the loom around the harnesses; many times these factory looms will hold water and oil and cause additional problems. I also stress the importance of electrical routing and the proper tensioning of wiring and harnesses in a piece of equipment. Wiring should be protected and only pass through openings that are completely protected. Wiring on engines and around components should be installed so they are hung by their fasteners and not resting on them. Many times, engine and engine-driven electrical problems are due to abrasion, cuts, and sawing that has occurred due to the vibrations caused by the engine. If these harnesses had been hung or installed underslung of their fasteners, some of these issues could have been avoided.
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Ground-engaging tools (GET) are an entirely different issue. GETs are some of the most expensive consumables we’ll have on a project. Each application needs to be considered independently along with the number of cycles per application. Many times, hard-facing, adding wear bars, pucks or wear strips will be more cost effective over time. When you take into consideration the lack of productivity until replacement that occurs on GETs, time spent before deployment to maximize useful wear life will be well worth it. In extreme cases and environments, “harder than steel” alloys can be specified and installed by specialized dealers. These extremely hard wear-resistant alloys are expensive, but on large mining buckets or in extremely harsh environments they will pay for themselves multiple times over.
In adding these hard, highly resistant wear metals, make sure to consider what that surface is running against. Oftentimes, the wear in a group is identified and corrected; but downstream, the wear is compounding and gathering in a larger, more expensive component. An example of this is foam-filled tires on telehandlers. I’ve seen situations were foam-filled tires were implemented to help with downtime associated with punctures and cuts, but then later in the project pin, bushing, carriage, boom and main frame wear had been accelerated to a point where more extensive and intrusive action was needed to remedy these issues. In extreme cases where long travel distances were necessary over semi-rough terrain, frame cracking was found in almost every unit with foam-filled tires, as the dampening and cushioning aspect originally engineered in the machine through the pneumatic tire was removed.
This “engineered maintenance” concept might not be perfect for every machine in every application on every project, but if we strive to look at maintenance with this concept in mind, maintenance truly will evolve into an overall engineered preventive maintenance mission and not just a PM task. Always follow the manufacturer’s recommendations and seek their advice, extend your intervals slowly, understand the application and the fluid/component history, use oil and grease analysis, use the proper lubricants and fluids that are formulated for the longer intervals you wish to achieve, and don’t be afraid to ask questions and push the limits. The goal is to be able to provide well-maintained equipment with as little downtime as possible to the projects, with the least amount of human interaction as necessary for this to be accomplished.