Original Date: 01/24/1994
Revision Date: 01/18/2007
Best Practice : Total Productive Maintenance
Harris Semiconductor has taken the increased productivity through machine maintenance philosophy to a new level with its global commitment to Total Productive Maintenance (TPM). TPM is a team process implemented through specific techniques that systematically eliminate defects and losses due to equipment. The methodology increases customer satisfaction, reduces costs, and improves product quality through improvement of overall equipment effectiveness (OEE).
The TPM philosophy is based on the concept that equipment degradation is at its worst on initial start-up but improves as man-to-machine interaction is exercised. The TPM principles include movement of product and process quality through a zero mentality zero waste, zero breakdowns, zero defects, zero delays; elimination of six equipment losses breakdown failures, setups and adjustments, idling and minor stoppages, reduced speed, quality defects and rework, and startup yield reduction; development of a clean, organized, visually controlled work place; focus on chronic losses and root cause preventative problem solving; development of equipment management systems; and increased operators awareness of equipment and its needs.
An OEE metric accounts for machine availability, rate efficiency, operating efficiency, and rate of quality. The machine availability metric is made up of machine breakdowns, repairs, set-ups, qualifications, and planned downtime. Rate efficiency metrics include reduced operating speed, minor stoppages, and technical assists. Operating efficiency takes into account idle time, no work, or no operator available. These inputs to the OEE can be used as a measurable goal directly related to manufacturing productivity and shipping good products. Since this metric requires data captured on the manufacturing floor, Harris has developed an electronic data capturing system. The operator presses one of ten buttons associated with an equipment state, and the elapsed times in each state are noted and transferred to a central database. Many capital purchases have been avoided through OEE increases; quality and production cost improvements have been observed on several production lines.
Another aspect of TPM is Clearing, Arranging, Neatness, Discipline, and On-Going Improvement in the manufacturing area. At one Harris location, as part of the clearing stage, over 2500 pieces of unneeded equipment were removed from the floor, and the way was cleared for the arranging stage, aimed at more efficient product flow. A subsequent annual visit by a customer to that Harris facility resulted in favorable comments on the condition of the manufacturing area, and it was ranked as the most improved of all facilities visited by that customer.
TPM implementation results have yielded 20% per year improvement rates for equipment and operator productivity, material waste, spare parts costs, capital avoidance, and quality improvements over the last two years on specific production lines.
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