McGroarty
McGroarty
McGroarty
McGroarty
McGroarty

How to create precision maintenance and eliminate waste-wear in production machines

July 17, 2013
Stanton McGroarty says most wear results not from the machine doing its production job, but from us not doing our maintenance job.

About 20 years ago, I was working with a fastener manufacturing company in the Midwest. In a successful effort to reduce cost and lead time for cold header tools, we began stocking hard blanks for dies and die carriers. When we needed a new die we would hard turn it instead of green turning, heat treating and grinding to get the same shape. CNC lathes and cutting tools had progressed to the point where the accuracy we needed was available from the hard turning process. Our main concern was the increased wear and tear that would result from turning hard material in the CNC equipment. After all, you have to sell a whole lot of bolts to pay for a new CNC lathe.

The economics of the tooling project were something really special, so we elected go ahead with the project and try babying our turning equipment to minimize damage. We figured we would continue at least long enough to see whether we could make the lathes hold up under the strain of hard turning. We took two new lathes, which just happened to arrive at that time, and declared them to be the hard turning machines. We assumed that we were starting with more rigid equipment, since it was new. Maintaining rigidity meant reducing wear, so we ensured maximum air and coolant flow to the work area, including through the tools. Out of respect for the harder, smaller chips we were producing, we improved coolant and lube oil filtration and increased change frequencies. Tribology was not a common science yet, but we did watch for chips and coolant in the oil. We also put our most skillful operators on the job, thereby minimizing dull tools, loose setups, crashes, and inappropriate cut loads.

I wish I could say that we applied a full-scale vibration analysis and frequent alignment checks for the welfare of the equipment, but we weren’t that bright in the mid-1990s. The precision requirements of the tools we produced did, however, ensure that we carefully maintained chuck and slide alignment in the work area. We also kept the machines as clean as possible and minimized the amount of dust and chips we blew into the slides, chucks, and other moving parts.

The trial period never officially ended, but the hard turning equipment became the most reliable metal removal gear in a huge tool room. The increased watchfulness and careful attention to PMs more than offset the strain of turning hardened material. In fact we told ourselves at the time that we had probably overestimated the difficulty of hard turning. Nevertheless, the hard turning lathes were in a class by themselves for reliability and precision, even though they were doing the toughest job in the shop.

Looking back from today, the story of the hard-turning lathes calls for a resounding “duh!” What we had done was conduct an early trial of precision maintenance. Cleanliness, pristine fluid maintenance, and careful, ongoing alignment had added up to the elimination of most wear that was coming from non-value-adding causes. Unbalanced loads, abrasion, and chemical degradation were not a part of these lathes’ work environment. As a result, they thrived.

Today, anyone who attends lubricant courses, vibration analysis seminars, or TPM classes hears that the bulk of wear that occurs to most equipment does not result from productive work. Too often it results from dirty oil, unbalanced installation, misalignment, impact damage, improper operation, and sloppy maintenance. To borrow a technical term from motorcycling, we “drive it like we stole it.” Equipment life, product quality, and OEE usually show the results.

Perhaps it would help if we introduced a term for this kind of wear. Let’s call it “waste-wear.” Such a term might keep us reminded of the fact that most wear results not from the machine doing its production job, but from us not doing our maintenance job.

“Not my fault!” resound the pained responses.

Yeah, well it is our fault. It’s our job to see that alignment, lubrication, and other PMs and PdMs enough to keep equipment healthy are designed and executed. That’s what isn’t happening — our job. But, look on the bright side, any enlightened guru will tell you this is very good news. Since we are causing the problem, it is in our power to fix it. Moreover, the way to fix it isn’t a mystery.

Kaizen, TPM, Six Sigma, lean everything, common sense, and most prepackaged approaches all start the same way. Pick an area where the battle is winnable and start doing everything right on a few machines. Here are some more pointers that have proven helpful over the years:

  • Select machines where the problems are a pain in the neck to an important part of the organization and enlist the management of that area to support your effort.
  • Make sure that the problems are understandable enough to make the technical portion of the exercise feasible.
  • Choose a name for the effort with more appeal and less risk than “start doing our job.” The short list above provides several possibilities, or you are welcome to use my personal favorite, “precision maintenance.” As more and more machines come under precision maintenance, uptime, availability, OEE, and whatever other productivity measures you use will begin to fall into line. The result will be manufacturing that provides a competitive edge.
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J. Stanton McGroarty, CMfgE, CMRP, is senior technical editor of Plant Services. He was formerly consulting manager for Strategic Asset Management International (SAMI), where he focused on project management and training for manufacturing, maintenance and reliability engineering. He has more than 30 years of manufacturing and maintenance experience in the automotive, defense, consumer products and process manufacturing industries. He holds a bachelor of science degree in mechanical engineering from the Detroit Institute of Technology and a master’s degree in management from Central Michigan University. He can be reached at [email protected] or check out his .
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Since precision maintenance is less rigidly defined than most buzzwords, it allows engineering and maintenance to prescribe what is right for each piece of equipment. Most of the time this means tightening up alignment, lubrication, and wear issues to where the tolerances should have been all along, often an order of magnitude tighter than tradition dictates. Most factory teams inherited some maintenance and operating practices that were not adequate to provide precision asset healthcare. If they had inherited precision maintenance and operating practices, the equipment would not be the problem area that we just searched out.

The precision idea in maintenance is that, probably with OEM help, we find out what kind of alignment, what quality of lubrication, and what custom PdM steps are required to make machines run for decades. Then we put those advantages into place. Most electric motors and drives will perform for decades if properly installed and maintained. Don’t believe it? Look at your equipment that isn’t causing problems. How long has it been running? Barring engineering problems, your problem machinery is different because it is not being maintained properly. Fill in this gap, and life will get better for everyone from the sweeper to the stockholders.

This isn’t just a technical drill, though technology is an important part. It also takes a change management effort to build momentum behind the changes. Create a core team that shares the “precision vision” and use your imagination to build energy. Put some paint and better lighting into the new precision maintenance area. Get your accounting function on the team with a financial translation of what improved OEE in the area will mean in dollars and cents. Begin with a 5S program to make the area a more attractive and safer place to work. If you want to start operator-performed maintenance or a similar program, now is the time to enlist help from the floor.

There is a set of three articles in the Plant Services library outlining the technical and teambuilding specifics of a “ready, aim, fire” maintenance blitz on problem equipment. They are below:

There is also a NASA standard to help with definitions of precision maintenance.

The technical project will be challenging work, but it is what we have all been trained to do. If your team creates an exciting occasion, with production support, it will be fun, and it will be successful. American manufacturers have never been more aware that all members of the operation are in the same boat. Now what is called for is good leadership to help them understand how to act like it, with precision.

Read Stanton McGroarty's monthly column, Strategic Maintenance.