A lesson in problem-solving, the old fashion way

Sam, the maintenance man, currently Maintenance Manager, grabbed his flashlight and hardhat off his desk and headed for the door on this April day of 1978.  

"I'll be out on Number 2's floor, if anybody wants me", he said as he passed by the maintenance clerk's desk by the door leading to the shop. The mill was a multi-machine, integrated mill in the Midwestern USA. 

This was third time in as many months that a dryer felt roll had failed without warning taking the felt with it. Sam was in no mood for any excuses as to what was the problem, he wanted answers and he wanted them now, because he knew his boss, the mill manager, would be breathing down his neck in a few minutes. 

"What is the problem?", he asked Ernie, his assistant standing on the machine aisle next to the after section dryers.

"Ripped the roll journal right out of the head, sheared it right off." his assistant responded as he started over towards the machine frame to show Sam. 

"What do you suppose is causing these failures, this is the third one we had over the last couple of months." 

"I don't know, we're just lucky this happened now instead of tonight or this weekend. At least we can get going right away without too much downtime." 

"Yeah, but any downtime is too much downtime, especially if it can be prevented." Sam grumbled as he crouched down to look at the end of the felt roll being dragged out between the machine frame. "Looks like there just isn't enough material here to withstand the forces, just sheared right off. Doesn't look overheated or anything. Shears off right at the shoulder going into the head. Is that the same as the last time?" 

"Yep, same exact. We just thought it was over-fatigue, a single incident. Looks like we got a bigger problem than that. Maybe the journals are just too small or too old. Maybe I should figure out a way to change out these rolls faster. Maybe we can have the vibration checked more often to see if we can expect a roll to fail, maybe we should just plan to change out one or two rolls each down."

"I think we had better have a solution to the problem, and quickly. I'm going to call Beloit (the machine OEM) and our [corporate] engineering department. Get this cleaned up and then we'll have a meeting to see if there is something we can do right away. Let's plan to meet in my office tonight at 5PM. Bring Norm (the shop foreman) with you. Okay?" 

"You got it." 

Returning to his office, Sam called his boss to bring him up to date, telling also that he had set up a meeting to discuss the problem for later in the day (the manager suggested bringing in the paper machine manager, as well) and then got on the phone to his contact at Beloit (where the machine had been built in 1959). 

"Hey, Tom, how you doing? Yeah? great! Hey listen Tom we've had a dryer felt roll failure here on No 2 and this is the third time in three months. The failure is always the same each time, the journal shears off at the head. Do you have anyone I can talk to about what might be going on? Yeah? Well, here is the drawing number and your original order number have him call me after he's taken a look at these, Okay? Thanks, Yeah, good bye."

Sam then called corporate engineering. "Jerry? Hi. listen we just lost another felt roll on the after section of # 2 machine and its the same as last time. We have a reoccurring problem and it needs to be corrected. Can you send Don down to a meeting this afternoon in my office? Yeah, five o'clock. Thanks. Good bye."

Later that day a meeting was held, attended by the paper machine manager, the maintenance manager, the assistant maintenance manager, the paper mill maintenance supervisor, the shop supervisor, the corporate paper mill project engineer and the mill manager.

"Tell us all what happened," the mill manager motioned to the maintenance manager.

"Well...first...and then, and then...." Sam brought everyone up to date.

"Anybody got any ideas?" queried the manager looking from face to face. 

"Most likely its lack of lubrication," suggested the paper machine manager.

"Oh crap, Jim, you always say that. You want to see the bearing housing? Its downstairs in the shop and it still has all the grease in it that you would ever want in a bearing housing, so let's drop that excuse right now." an angry maintenance supervisor responded.

"Look you guys, as much as you both like each other lets try to keep this civil, Okay? Now has anyone got another suggestion?"

"I called Beloit today and talked to one of their design engineers" Sam offered, "he told me that from the sounds of the failure it might be that the felt roll is sustaining some unexpected loading resulting in excessive forces on the journal, causing it to shear at its weak spot."

"What does he mean by 'unexpected loading'?" asked Jim, the paper machine manager.

"Well this roll was manufactured way back in 1959. It was designed for a machine speed of 1600 fpm. We're running a lot faster than that."

"What's the safety factor?" asked the mill manager. 

"That's just it, speed shouldn't be the factor...by itself, according to the engineer."

"Jim, you've been on this machine for awhile, what have we changed on it since 1960 that might be putting more stress on the felt rolls?" the mill manager asked.

"Hummm. 1960 to today..." Jim mused. "Hey! You know what it is...of course! of course! why didn't we think of that, of course!" 

"What, Jim?" the mill manager said sitting up, "Don't keep us all in suspense."

"Synthetic felts. We used to run those cotton felts years ago and then we all switched to synthetic, great idea, only it takes a lot more tension on the felts to run them, otherwise they slip, made out of plastic, you know."

"Of course!" responded Sam. "Why didn't anyone think of that? And after all these years of increased felt tension we're losing felt rolls left and right." 

Problem identified. Shrugging shoulders, looks of innocence.

Solving the problem did not turn out to be quite as easy. 

New felt rolls with a larger roll diameter were required, but over time and with intermediate stop-gap measures, e.g., higher grade journal material and larger diameter journals on the rebuilt rolls and less felt tension, while the new rolls were being fabricated, the mill was eventually able to correct the problem.

The point is simple. You can't solve a problem until you recognize what the problem is.

Most times the real problem is overlooked because the symptoms are diagnosed as the problem. 

How many times have 'solutions' been aimed at speeding up the repair or replacement time rather than correcting the root cause of the problem?

How many problems reoccur because the real problem wasn't addressed at the time of failure? 

Solving problems is not such a difficult process. You meet, analyze information, propose ideas, take corrective action, observe the proposed solution and you react accordingly.

Quite simple. Quite old fashion.  

Perhaps too simple and not trendy enough to be used today in this complicated, ‘modern’ world ever seeking new, fresh, technology-laden tools.  

Funny how the failures still keep happening in spite of the upscale, 'world-class', sophisticated approaches being touted for maintenance to solve problems.  

Do you suppose the equipment isn't listening to those expertly proposed methodologies?