PdM is Not Precision Maintenance (Coaches Corner)

Another great Coaches Corner post from Allen Canaday:
During a recent discussion with a student he asked me why the failure rate at their facility wasn’t improving.  Over the last two years they had invested in the purchase of various PdM (Predictive Maintenance) technologies and trained personnel on their use and application.  The facility had conducted a criticality analysis and SFMECA (Simplified Failure Mode Effects and Criticality Analysis) to determine their critical failure modes.  For the most part, they had purchased and trained on the PdM technologies that would best detect the early onset of the failure modes identified in their SFMECA.  Why were assets continuing to run to failure even though failure modes are being identified? Why aren’t the PdM technologies preventing failures in our facility, he asked?
The answer in two-fold. This wasn’t the first time I fielded this question.  When I asked the student about the precision maintenance techniques utilized in their facility, he asked, “What do you mean by precision techniques”?  This was exactly the answer I was expecting! PdM technologies are diagnostic tools designed to find the early onset of failure modes, these tools don’t make the repair for you, they just help you determine what needs to be repaired.  These tools can’t tell you exactly how long you have prior to functional or catastrophic failure, the data acquired from these tools only tell you your asset has a failure mode and if no action is taken, it will eventually fail.
Precision techniques and instruments, along with the proper training on their use, increases the probability that when the repair is made, failure modes aren’t introduced into the asset resulting from the corrective work.  Precision techniques include job plans that consists of proper task-step sequences and performance standards that convey proper tolerances and measures to the technician performing the corrective work.
Next, I asked the student to explain their backlog prioritization for planned work.  Again, he asked “What do you mean by backlog prioritization”? I explained that no matter what PdM technologies you utilize, the findings must be converted to a work order to be planned and scheduled.  Even the PdM generated work orders become part of the total backlog and must be scheduled based on their severity or risk to the organization.   Poor work order prioritization practices can render your PdM efforts meaningless unless your work execution practices are robust enough to effectively prioritize work orders in your backlog.
PdM is not precision maintenance!  The two complement each other.  However, without the implementation of precision maintenance in your work execution process, expect to continue making repetitive repairs on many of your assets, even on the assets you’re utilizing PdM technologies to detect the early on-set of failure modes.