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Total Productive Maintenance (TPM)

Summary of TPM


TPM was developed in the 1970's as a method of involving machine operators in the preventive maintenance of their machines - a reaction to increasing specialization and centralization of the maintenance function that had created division-of-labor barriers between operators and the maintenance of their machines and equipment.

Autonomous maintenance activities tap the knowledge and skill of the people who work with the equipment on a daily basis, and gives operators a stake in the performance of the equipment. This involvement is part of a larger philosophy of continuous improvement, or Kaizen, that touches all shop floor activities. Involving machine operators also makes the regular maintenance people more productive by focusing them on more extensive preventive maintenance (PM) tasks.

The overriding objective of TPM is the elimination of LOSSES. Losses, or waste, includes equipment downtime, defects, scrap, accidents, wasted energy, and labor inefficiency.

Equipment reliability is a cornerstone of a lean production system. With little or no buffer inventories, equipment failures directly impact production volumes and customer service, so effective preventive maintenance is a critical activity. By bringing together people from all departments concerned with equipment into a comprehensive PM system, equipment effectiveness is raised to the highest possible level.

Most TPM programs are built upon autonomous small group activities - the people closest to the action. This requires the support and cooperation of everyone from top management on down.

Benefits of effective TPM include the following:

Concept of Zero

The goal of TPM is to drive all waste to zero: Zero Accidents, Zero Defects, Zero Breakdowns.

On the surface this may seem impossible, but is it possible to run for an hour with no accidents, defects, or breakdowns? If it can be done for an hour, can it be done for two hours? a shift? a day? and so on.

The Concept of Zero is built upon error-proofing activities, or Poka-Yoke, in the design of the process to make it impossible to make and pass on defects. Poka-Yoke concepts are also commonly applied to equipment to prevent breakdowns (e.g. automatic lubrication systems).

Measuring Performance


The primary metric to gauge TPM performance is Overall Equipment Effectiveness, or OEE.

OEE is a combined measurement that shows the impact of equipment availability, equipment performance, and quality of output. The metric is calculated by multiplying Availability x Performance x Quality, as detailed below:

Availability:

100% minus the following:

Performance:

100% minus the following:

Quality:

100% minus the following:

EXAMPLE: So, if Availability is 95%, Performance is 97%, and Quality is 98%, then OEE is .95 x .97 x .98 = 90.3%

Core Elements of TPM


There are five core elements to a TPM program:

Maintenance Activities


There seven primary Maintenance Activities to support the Five Core Elements of TPM:

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