Preventative Maintenance: Is It Broken Yet?

Mar 24, 2014

Have you heard the term “world class maintenance”? I am by no means an expert on the subject, but my understanding is that it refers to performing consistent preventative maintenance on machines and other equipment on a regular basis before a breakdown occurs to minimize or eliminate downtime.


When I first heard it, it made perfect sense. Anyone who works in manufacturing surely knows that unscheduled down time can be costly. I was speaking with someone the other day who works for an auto manufacturing plant, and they follow the WCM theory. I found it very interesting however when he started telling me about all of the overtime he worked two weeks ago because of a particular robot that kept going down.

The production line that he was working on was machining with two mirror lines both feeding into an end line washing station before heading to staging and assembly. The robot was in the washing component of the line. The purpose was to pick up the part after it had been machined and rotate it around for thorough washing. He proceeded to tell me that the motors on the robot had been replaced twice in the past few months and management did not want to stop the line to do so.

So my first reaction was why are we fixing the robot after the fact? If we were doing our preventative maintenance (PM) wouldn’t we have known there is a problem with the motor? Now I know you can’t catch everything in a preventative fashion because sometimes things break unexpectedly. But twice? The new motor breaks again and no one wonders what is going on? I do not have the knowledge, nor the skill to fix a machine of such nature. However, as I kept probing with questions I found out the Company had all of the parts to perform the PM for nearly a year, and did not do it. Anyone as intrigued as I was?

Here’s the cincher, the robot used to perform the washing function was NOT waterproof! Hence, the motor kept getting wet and burning out. This particular person had only been privy to the last two motor changes. Apparently there had been more. They were waiting on the robot to “die” before they replaced it with the one that had been “waterproofed”.

I can tell you that this individual spent almost three full days including overtime working on the second breakdown. Did anyone look at this? Does it really make sense when we have the replacement robot to keep repairing the old one? The cost of new motors that are going to knowingly fail, the downtime on the line, the wages and overtime of the maintenance crew, all for what? I asked him why and this was the answer I received: “we don’t stop. Management does not want to stop the line for anything and to schedule a shutdown of the line to replace the robot is failure because we are unable to produce anything.”

Can someone please explain? In my world, we would have saved more money by scheduling the down time and replacing the robot one time as opposed to the numerous times spent trying to repair it, knowing that it would not work. This one seems obvious to me. Better decision making will result in better costs. Matter of fact, just being logical will result in better costs!

Categories: Cost Accounting