Double-digit productivity improvements resulting from workflow redesigns and new-capital equipment investments always get a lot of attention. But over time the returns from many smaller, more methodical changes and investments can rival more highly visible projects. Total productivity maintenance (TPM), for both existing and new equipment, offers just such an opportunity.
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At the heart of an effective TPM program is the core understanding that equipment can be maintained to perform reliably with high levels of quality for many years. The five pillars of TPM are autonomous care, planned maintenance, preventive maintenance, education, and quality.
For preventive maintenance and other purposes, one of the key elements of TPM is tracking overall equipment effectiveness (OEE), which combines machine availability, performance and quality metrics. Machine availability reports time lost due to planned and unplanned downtime, including setup time, in a given period. Machine performance helps identify losses due to jams and minor stoppages that result in slower speeds than what’s standard. And the quality component of OEE exposes losses due to defects or material loss.
In some cases, the act of gathering these data exposes opportunities for improvement and prompts maintenance teams to develop a roadmap for improvement. Over the long term, OEE can be used to schedule preventive maintenance activities after maintenance personnel translate its component metrics into leading indicators that will prevent losses before they occur. Similarly, planned maintenance starts with the recommendations of the equipment manufacturer. As onsite experience is gained, and the root causes of unplanned downtime are understood, the appropriate maintenance tasks should be added to the factory recommendations.
Implementing autonomous maintenance practices requires that machine operators become part of the maintenance support system. In addition to running the equipment, operators are expected to perform daily equipment cleaning, inspection, and simple maintenance jobs that require little effort but have a big impact on maintaining basic equipment conditions.
In practice, maintenance managers will typically create a step-by-step inspection route with a checklist for operators to follow and report any issues requiring follow up by technicians. Creating this standard usually starts with a thorough cleaning and check of the equipment with covers and guards removed to expose the inner workings. Maintenance personnel or a TPM team will then establish lubrication standards and mark key areas on the equipment that need to be checked regularly.
To capture the full benefits of a TPM program, machines must be audited regularly, and supervisors must review both inspection activity and machine performance with operators. Area managers will review the performance metrics with their supervisors, identify opportunities to make improvements, and remove any barriers to making those improvements. Following such practices, one manufacturer with which TBM worked with improved OEE 15 to 20 percent in 18 months, with additional gains on the near-term horizon.
First published Jan. 16, 2014, on the TBM Consulting Group blog.
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