Total productive maintenance (TPM) is yet another three-letter acronym imported from Japan that has been slowly growing in popularity across North America during the past several decades. It was closely tied to just-in-time (JIT), total quality management (TQM) and now lean manufacturing. It also can be considered an extension of preventive maintenance (PM). A large component of TPM is its coordinated operations and maintenance-team activities.
At the heart of TPM is the notion that equipment effectiveness must be maximized through the elimination of defects, downtime, slowdowns and so on. To this end, TPM starts with autonomous maintenance — the idea of having the production operators maintain the equipment they use. Furthermore, small groups or teams similar to Quality Circles or Kaizen improvement teams facilitate education, brainstorming and implementing changes.
CMMS can play a key role in ensuring the operations and maintenance function have the tools required to make a smooth transition to a TPM environment. For example, the CMMS can be used to establish performance measures and targets used in planning for TPM. Standard preventive maintenance routines can be established at optimal intervals of time or meter readings, or tied to events or conditions being monitored. Recording the quality and performance standards for each PM routine allows tracking variances to actual time and quality readings.
The more advanced CMMS packages have analytical tools to examine data, such as Pareto analysis for determining the highest-cost problem codes, or the most costly equipment to repair and possible root causes. Another key analytical tool calculates the total cost of ownership for critical equipment and determines how it can be minimized while maximizing equipment availability, utilization, performance, reliability and quality of output. Management can use these analytics to improve overall equipment effectiveness.
Equipment effectivenessThere are two objectives to pursue when trying to improve equipment effectiveness, namely maximizing output and minimizing inputs. Productivity, defined as output divided by input, is therefore increased. Output is not simply product volume. Factors such as cost, delivery and quality must be measured as well. Even safety, pollution and attitude can be considered outputs from the production process, and must somehow be measured and controlled.
Inputs to production include labor, material, equipment, energy, facilities and land. The cost of inputs must be monitored and reduced. Although the cost of every input has risen during past few decades, automation has decreased the labor, facilities and land components for many industries at the expense of the remaining three.
The goal of TPM is running equipment effectively under ideal operating conditions to achieve maximum productivity. This means eliminating losses and waste (Sidebar). It’s imperative to establish a measurement system for these variables and to track progress in eliminating them. The measures must be easy to record accurately, otherwise people will not bother providing input data.
CMMS and ERP vendors have been improving user interfaces during the past few years to facilitate data input and extraction. One of the key breakthroughs is the interface with remote technology, such as PDAs and bar code scanners, as well as shop-floor data collection systems such as HMI and PLC equipment.
Other calculations need to be made. Equipment availability measures the percentage of time a machine is available for production. Operating efficiency incorporates the percent difference between ideal and actual machine cycle times, as well as machine speed during the period of operation. Overall equipment effectiveness (OEE) is the product of the latter two percentages and the rate of good-quality product (100% minus the defect rate). Other measures include mean-time-between-failure (MTBF), number of improvements that employees suggest and per capita training expenditures. The more sophisticated CMMS vendors provide the analytics required to calculate some of these measures.
In North America, labor unions and management have formed a clear separation between maintenance and production. This is the most obvious reason for the slow acceptance of TPM or, more specifically, autonomous maintenance. The few North American companies that have overcome the stereotypes have benefited accordingly. Better communications, improved employee attitudes and placing responsibility for preventive maintenance and minor corrective maintenance at the front line lead to improved equipment effectiveness.
Implementing autonomous maintenance requires not only a change in corporate culture, but a heavy investment in training. Operators who have always said "That's not my job — call maintenance," must now acquire a sense of ownership as well as the skills for implementing their new accountability. Operators are asked to keep the equipment clean, well-lubricated and secure. Minor repairs and adjustments are also the operator’s responsibility. Each is trained to inspect, measure, continuously diagnose and fix problems.
Operators who take swift corrective action are essential to improving equipment effectiveness. New standards must be established to incorporate the additional tasks and targets must be established for maximizing equipment uptime. The CMMS can be used for tracking actual versus target performance.
There’s one common mistake you should avoid when implementing TPM and are transferring work from maintenance to operations. Operators are often denied access to the CMMS, which makes it difficult to enter data and, in turn, to compile an accurate history for analysis.
Team activitiesTPM program success depends on a formal operations and maintenance team organizational structure superimposed on the existing structure. Groups meet on a regular basis and on company time. Teams’ success or failure depends heavily on the motivation, skills and training of team members.
Management must promote a working environment that fosters positive change. This can be accomplished through involvement in the program, providing physical surroundings conducive to work and meetings, and monetary support for the TPM program and the ideas it generates.
Team-member training must have both technical and behavioral aspects. Technical training includes fastener and joiner theory; bearing maintenance; the basics about gears, belts, chains and pulleys; sealing techniques; basic tribology; and principles of electrical, pneumatic and hydraulic systems. Safety is an essential component of every facet of technical training.
Behavioral training includes motivation theory, group dynamics, brainstorming techniques, problem-solving and management of change. Behavioral training ensures that the technical training is exploited to its fullest.
Finally, team members need to be trained on what and how data is to be captured on the CMMS, how to use the numerous analytical tools available, and the appropriate response depending on the results of the analysis.
E-mail Contributing Editor David Berger at [email protected].