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.