Maintenance on the Move
By Cliff Williams
This article is part of an ongoing series. The introduction appeared in Machinery & Equipment MRO's Feb. 2005 issue and the series has run in every issue since. Previous instalments are archived o...
February 1, 2007
By Cliff Williams
This article is part of an ongoing series. The introduction appeared in Machinery & Equipment MRO’s Feb. 2005 issue and the series has run in every issue since. Previous instalments are archived online at www.mromagazine.com. In this issue, we pick up where we left off in our December 2006 issue. Maintenance manager Bob Edwards and his team at the Plentya Paper Company have received the go-ahead to proceed to the next step to achieve Overall Equipment Effectiveness.
t was great! Joe had given us his blessing to carry on with the change in maintenance tactics and so it was time to arrange a meeting with the entire maintenance group.
“Here you are Carol, “I said as I returned the books she had loaned to me so I could prepare for Joe’s meeting. “It went very well. Joe has said he will support us in moving maintenance into the 21st century, provided we keep him up to date with the financial side.
“I think I’ll have to get copies of all of those books so I can make sure we do things in a structured way and we don’t miss anything. Can you please schedule a meeting for the whole group for Monday?”
“Sure, no problem,” replied Carol. “Do you want me to prepare anything for the meeting?”
“It would be great if we had a one-page handout that summarized the sections in the book that covered the different maintenance tactics — you know, breakdown, preventive, predictive and proactive,” I suggested.
“That’ll be easy for me to do. I’ve more than likely got one already,” answered Carol.
Monday morning rolled around and we had a packed meeting room. It seemed that even the guys who were scheduled to be off had come in for the meeting.
“First of all I’d like to bring you all up to speed with what’s been happening.” I told them about the success with the ultrasonics and my discussions with Joe Davis and how he had given us the go-ahead.
“John will be in later this week to do some vibration analysis on the pulper gearbox in stock prep. You remember the one that caused us to slow down the machine the other month? But what I’d like to do today is set the foundation for building this new maintenance system and to make sure we all understand the path we’re going to take.
“First and foremost, as we found out in the Jeopardy Game, we have to get as much information on the work orders and into the CMMS as possible as this will help us identify the immediate problem areas. The next step is to look at the tactics available to us from breakdown to preventive through predictive eventually to proactive.
“By the way, which tactic do you think is best?” I asked the group.
After a couple of people had given half-hearted guesses, I suggested that it depended on the equipment and the way it failed. “Carol has some handouts and she’s going to explain what I just discussed in much more detail.”
“I’ve got the handouts but since when was I expected to explain them?” Carol asked me.
“I’ve heard the way you talk about the subject and I think your enthusiasm will carry over to the guys,” I whispered to her.
“Okay, let’s start with breakdown maintenance,” she began,” otherwise known as run-to-failure — it’s where we don’t do anything until the equipment fails, sometimes a valid tactic.”
“Oh, we’re going to be popular with management when they ask why the pulper failed and we tell them we decided to run to failure,” said Ivan from stock prep.
“I said ‘sometimes’,Ivan,” replied Carol. “Let’s take a car, for example. When do we change the headlights?”
“When they fail, of course,” replied Ivan, a little sheepishly.
“Right!” Carol enthusiastically responded. “But why don’t we change them every six months?”
“Because they can last a lot longer than that — who knows how long. I’ve changed a headlight and it has failed the first time I used it! I always get a free exchange, if I have the receipt, but there’s still the inconvenience,” laughed Ivan.
“Exactly, we really don’t know when the headlight is going to fail and there’s no real indicator that it’s going to fail, so we run to failure,” explained Carol. “If you think about our proximity sensors or PLC cards, they’re pretty much the same. But let’s think about the car scenario again. Imagine if it was your job to drive through narrow country roads at night — every night. What might you do to make sure you could see the roads okay?”
“Wear a miner’s helmet,” shouted Dave, which started everyone laughing. “But seriously, if it was that important, I’d carry a spare headlight in my trunk.”
“Perfect answer, Dave,” said Carol, “but if the driving was mostly done during the day, we might just wait until the headlight fails until we bought a new one, as it reduces the possibility of it getting damaged in the trunk. Imagine going back to the store and trying to convince them that you’ve been carrying this headlight in your trunk for six months and now that you’ve had to use it, it failed — think they’d believe you?
“For those sensors that are going to shut down major pieces of equipment, we need to make sure we have spares, but for those that don’t have a great impact, we can wait to buy one; it’ll help with inventory control.
“So you see, run-to-failure can be acceptable, but it depends on how the equipment fails and what the consequences of the failure might be — that determines how you prepare for it”
“I get it now” said Ivan, “but what about this preventive stuff — isn’t that what we do by now changing belts every six months?”
“That’s it, Ivan, preventive maintenance (PM) is typically rebuilding or changing equipment based on a frequency — it can be months but it could also be hours run, like we do with our compressors — or it could even be based on the number of tonnes of paper run, or batches made. Again let’s think of the example of a car. What do we do preventive maintenance on?” asked Carol.
“That’s easy — I change the oil every 5,000 kilometres,” replied Ted.
“Right again,” said Carol, encouraged by the interaction she was getting. “But why do we do that?”
“Because that’s how long it takes for your oil to break down and not be able to lubricate,” answered Ted.
“But how do we know that?” probed Carol.
“Because they analyzed it over the years,” said Ted.
“But if they can analyze the oil to determine if it’s good or not, why don’t we do that, rather than just change it every 5,000 kilometres?” asked Carol.
“It costs me $15 for the oil and the filter and even if you get it done at a garage it only costs about $25 — I’m certain it would cost that much to get the oil analyzed,” said Ted.
“Exactly, and if the analysis comes back that the oil is no good, then you have to change it anyway,” said Carol. “If it’s good, then you have to get it analyzed again later and the question becomes how often you analyze it. Either way it doesn’t seem to make economic sense to go the analysis route and we certainly can’t let it run to failure.”
“What about changing the belts every six months?” asked Ivan. “Couldn’t we just check them?”
“Don’t forget the philosophy of Jack, our old maintenance manager. If it fails once you’re unlucky, if it fails twice you’re a fool. That’s why we change them every six months,” offered Stan.
“But even that doesn’t work, because we still get belt failures,” replied Ivan.
“You’re right, Ivan,” I interrupted. “That’s because age is only a small part of the reason equipment fails. There are many stresses that we put the equipment under that cause it to fail. If you remember those agitator belts we changed last month, they had delaminated, and you figured out it was because they were overheating and the big guard was just keeping the heat in. So you put some expanded metal windows in it.”
“Okay, but it takes a couple of hours to get that agitator guard off to inspect the belts, so as you’ve got it off you may just as well
change the belts,” replied Stan, determined not to be beaten.
“You’ve got a point there, Stan,” I conceded.
“But what if there was a way you could inspect the belts when they are running?” asked Carol.
The room exploded: “Are you nuts!” “The ministry will kill you!” “Don’t let the safety committee hear that!”
“Whoa! It will be done safely!” shouted Carol. “I’ll explain when we talk about predictive maintenance. Let’s finish talking about preventive. What we’ve seen is that with some things, it makes sense to change them, but with others, it seems we are throwing away parts when they are still good and we are shutting down equipment just to find out if the parts are good, both of which cost the company money. If there was a way to get away from that scenario, the gains for the company could be huge.”
“Even that is only part of the story,” suggested Pete. “What about the times we do PM on a piece of equipment and some other piece breaks down when we start up?”
“Spot on!” I jumped in and explained that studies showed that more equipment failed on start-up than at any other point in time. “We make adjustments to parts of the equipment to compensate for wear. When we start up, we sometimes forget to revert the settings. Sometimes we assemble things incorrectly, sometimes we contaminate when we PM and we all know the biggest stress is getting from rest to run mode.”
“So that brings us to predictive maintenance,” started Carol.
“Hang on a minute, Carol. From the little I know about predictive maintenance, I see it’s a complicated issue. I think we’ll need another meeting dedicated to this topic. I’ll see if John, the vibration guy, can come in next Monday and help you out with it. So guys, it’s same time, same place, next week.”
I took Carol aside. “Thanks Carol. That was great. I’m beginning to think that if we’re going to improve reliability, we need someone dedicated to it, so if you’re interested, I’ll talk with Joe about you becoming that person.”
“Wow, that would be great, Bob. That’s exactly where I’d like to go,” answered Carol.
“No promises, but I’ll start the process,” I said.MRO
Cliff Williams is the maintenance manager at a Coca-Cola Ltd. facility in Toronto, Ont., and a consultant with TMS Total Maintenance Solutions of Markham, Ont. He can be reached at firstname.lastname@example.org.
Remember the five E’s of change:
* Explain why
* Educate what
* Easily understood
* Encourage participation
* Everyone benefits.