Total Productive Maintenance
A successful TPM program will help you eliminate defects, machine breakdowns and accidents.
By Tom Dossenbach
This month I continue to discuss some of the tools of Lean Manufacturing that are available to help you reduce waste in your factory and thus increase your profitability and competitiveness.
As I have stated repeatedly, the central goal of any Continuous Improvement or Lean Manufacturing effort is to eliminate waste from all plant operations. The topic for this month, Total Productive Maintenance (TPM), is especially relevant in woodworking plants today because maintenance, unfortunately, remains largely a reactive function instead of a proactive one. Anytime a machine breaks down and causes a delay in the production process, a machining error occurs that reduces the quality of a part or, worse yet, there is an accident at a machine, costs rise and your ability to compete with imports is reduced.
What is TPM?
Maintenance is still viewed much in the same way quality control was in the past. Specifically, quality control used to be a measurement and fix-it exercise. When a defect occurred in a furniture factory, everyone ran to fix the defective product and maybe, just maybe, they would look into why the problem occurred in the first place.
Plants that practice Total Quality Management today empower employees not only to identify quality problems but to take corrective actions to prevent that defect from ever happening again. This is known as Error Cause Removal (ECR) and is a component of a Zero Defect program.
In the past, plant maintenance crews were responsible for keeping the machines running and fixing them when they broke; it was as simple as that. The accompanying cartoon depicts the old perception of a maintenance guy happily running to fix a machine that is creating problems and to rescue the production quota for the day. Time-based preventive maintenance replaced this traditional role as the value of preventing machinery breakdowns became obvious, much the same way as quality management focused on prevention rather than cure of quality problems. Unfortunately, along with this realization, too often an adversarial relationship sprang up between maintenance and production characterized by an "us vs. them" mentality.
Production supervisors and workers felt that if maintenance personnel did their job, there would be no breakdowns. On the other hand, maintenance people almost universally thought that the machine operators were abusing the machines and causing work stoppages through their negligence. Actually, both parties were right to a degree.
Today, Total Productive Maintenance reflects a shift in the old paradigm. Implementation of a successful TPM program requires machinery to be maintained at its top running efficiency as an essential part of maintaining quality, productivity and safety. It is also recognized that the efforts to achieve this must be a part of a continuous improvement process throughout the company. Furthermore, it is a vital part of striving toward Lean Manufacturing because fixing a broken piece of machinery or equipment is definitely not a value-added activity and adds unnecessary cost to a product or service. Thus, TPM involves teams of operators caring for their machines and striving with maintenance personnel and company management for no machine-related production delays of any kind.
Three Goals of TPM
The goals of Total Productive Maintenance are simple and straightforward.
The first goal of an effective TPM program is to achieve zero breakdowns, zero defects and zero accidents in all of a company's processing areas. A successful TPM program will ensure that all machinery and equipment function without disruptions to production related to mechanical problems, product quality problems or worker accidents - all causes of waste and lower productivity.
The second goal is to establish a comprehensive maintenance scheme that will achieve the first goal for the life of the equipment. After all, a lofty objective such as the one spelled out above must have a plan in place to make it happen.
The third goal is to involve and empower all employees who specify, design, maintain or use the machinery to implement the plan that has been created.
Unfortunately, many plants - large and small - still consider maintenance as a costly overhead expense. But it is ultimately less costly to pay now through the development of a comprehensive preventive maintenance program than to pay later when a machine malfunction derails your ability to efficiently produce quality products on time.
Repair costs and the related costs of lower productivity, quality problems and accidents are all unnecessary and avoidable. That's why the goals of TPM are to avoid these costs in a continuous process of prevention and improvement, not a program of the month. Hopefully you understand the term Zero Defects with regard to quality management and see the benefits of this approach. This very same approach applies to the three goals of TPM.
A Structure for Implementing TPM
How should you go about making TPM work? What steps are necessary for implementing a successful program in your plant? Here are six building blocks that can serve as the structure for your TPM program. (See Diagram to right)
1. Implement 5-S Workplace Management in your factory and make sure you follow all steps. In my opinion, TPM is doomed to failure without 5-S as a foundation. (Brush up on 5-S by reviewing my June 2000 column.)
2. Make improving the reliability of your machinery part of a Continuous Improvement process by getting teams involved in rooting out the causes of process defects, including reduced material yield, machine slow-downs, set-up downtime and equipment failure. After these problems are identified, their causes should be thoroughly analyzed and corrective actions taken to eliminate future occurrences. Regularly scheduled preventive maintenance by qualified personnel is a part of this step.
3. Establish a formal, technical training program to increase operator knowledge and skills in the proper operation and care of machinery. Teaching operators how to do their jobs better goes a long way toward meeting the three goals of TPM: eliminating defects, breakdowns and accidents. This program should include the daily inspection and cleaning of machinery that is necessary to identify potential problems.
4. Establish an autonomous (do-it-yourself) maintenance plan for your machine operators. They must alter the way they view the equipment they use and their responsibilities as outlined in the above points. Because they run the machinery, they should be on the look out for any anomalies that indicate the need for further investigation, immediate adjustments, or repair - including cleaning, inspection, lubrication and other caretaker tasks that will prevent defects, breakdowns and accidents.
5. Establish a planned maintenance schedule for the maintenance department that dovetails with the autonomous maintenance plan of the individual operators. Maintenance engineers are a critical part of TPM and must be interwoven in this team effort.
6. Finally, those responsible for specifying or purchasing machinery should join the TPM team and assist in implementing maintenance-free machinery to the highest degree possible. This is done before new machinery is purchased, as well as by modifying existing machinery. Everyone in the company must become aware of and involved in TPM to maximize its success.
The Benefits of TPM
Last month, I mentioned the importance of implementing preventive maintenance programs for work cells. You can imagine the potential staggering loss of productivity that can occur in a work cell, where two or more machines are dependent on each other to complete a task. Yet, every plant is equally dependent on machinery that is ready for top performance on demand - cells or no cells.
If you have five machines through which all of your products must flow (such as a cut-off saw, planer, ripsaw, moulder and sander) and each is reliable and ready to run at top efficiency for quality and production 95% of the time - what percent of the time would you expect to experience no work stoppage? The answer is not 95%. Instead it is 95% X 95% X 95% X 95% X 95% = 77%. This is why it is critically important to aim for 100% operational efficiency through TPM.
I was in a plant recently and noticed that some of the pieces coming out of the ripsaw had moisture streaks on them. I immediately thought there must be excessive oil from the chain oiling mechanism finding its way into the lumber. Operators were actually culling out these pieces and throwing them in a pile oblivious to the implications. As stupid as that sounds, actions like that are common in small shops and large woodworking factories everywhere.
Imagine if this experience had actually occurred in your factory or shop. Would you be surprised if no one did anything about it until a visitor mentioned it?
Now, ask yourself, "Is TPM for us?"
Tom Dossenbach is managing director of Dossenbach Associates LLC, a Sanford, NC-based international consulting and research firm. Contact him at (919) 775-5017 or at www.dossenbach.com.
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