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7:24 pm
August 8, 2013
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From Our Perspective: Taking Back The Normal

ken bannister thumb thumb thumbBy Ken Bannister, Contributing Editor

At this year’s MARTS conference, Jeff Dudley, former Corporate Director of Reliability and Maintenance for The Dow Chemical Company, delivered the keynote address entitled “Are You Reliable Enough?” In it, he explored the problem of maintenance departments not simply normalizing abnormality, but going above and beyond to actually embrace this new state.

While working with a mechanical maintenance group setting up a reliability-based approach to their work, I was asked to review a major machining center at the site. The machine’s hydraulic material-handling system was particularly problematic—as the group characterized it, “leaking like a sieve” after only eight months of operation. Upon further questioning, it became evident that all of the plant’s fixed hydraulic systems suffered from major leaks. Interestingly, none of the site’s forklift hydraulic systems leaked: As it turned out, those systems are maintained by a dedicated mechanic. This situation is a classic case of something that was abnormal having become an acceptable norm.

Looking into the site’s preventive maintenance (PM) job tasks revealed that the entire approach revolved around ensuring that hydraulic-oil-tank fluid levels were checked and “topped up,” and that newly designed and installed “oil catch pans” were vacuumed out with a fluid vac—on a daily basis, due to the rate of leakage! When questioned about the frequency of these activities, the maintainers believed, in light of the system’s design, that their approach was acceptable. Some of them actually thought the machine was designed to leak as a way to ensure a constant flow of fresh lubricant through the system!

Further investigation revealed that none of the high-tech electronically monitored hydraulic filters were connected to the machine interface—and since both were operating in a bypass mode, they offered no machine protection. The PM to change the oil and filter on a quarterly basis had never been acted on, as it was felt the daily PM had rendered it redundant. Once again, the abnormal had become normal.

Clearly, this maintenance group had become rather short-sighted: They had found it easy to deal with a simplistic, symptom-based maintenance approach. As long as no one questioned the excessive lubricant costs or fees for disposal of used oils—and as long as the machine availability didn’t affect production output—the new normal prevailed.

Breaking this mold and moving toward a reliability-based approach isn’t as difficult as you might think: It just requires an open mind and the ability to ask “why?”

In this group’s case, highlighting the abnormality of their symptom-based approach (that NEVER addressed why rod and valve seals were leaking) and comparing it to the forklift mechanic’s approach was quite an eye-opener. It led the team to question their motives and develop a PM approach focused on preventing leaks rather than just managing them. After a series of “asking why” sessions, the group realized that the leaks were NOT part of the machine design after all, but were caused by poor housekeeping, missing breather caps on reservoirs and dirty fluid-transfer equipment, leading to dirt ingression that was ineffectively filtered. Success meant embracing reliability and “taking back the normal.” Good luck in your own efforts! LMT

kbannister@engtechindustries.com

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