The losses limiting equipment efficiency 

Maximizing equipment efficiency means ensuring they operate with their designed functions and peak performance. Any time the equipment fails to operate at its designed function and peak performance evidences the existence of losses that limit its overall effectiveness/efficiency (OEE).

Losses in working hours are classified into three main categories, containing eight losses that cause problems.（The chart shown below)

（1)  Downtime Loss

Downtime loss refers to the various time losses caused by situations in which equipment cannot be operated, even when operation is required. 

"Breakdown Loss" (time loss due to equipment breakdown)

"Setup & Adjustment Loss" (time loss incurred for product changeovers and for adjustment/trial processing)

"Cutting tool replacement Loss"(time loss caused by replacing tools, such as grinding wheels)

"Startup Loss"(time loss during the production startup phase until normal operation is achieved)

These are the visible losses that can be grasped from daily reports recorded by operators. Therefore, accurately defining losses and establishing a culture of measuring losses are crucial.

（2)  Performance Loss

Performance loss is defined as the efficiency degradation losses resulting from the actual productivity falling short of the equipment's designed capacity/performance.

Performance loss includes "minor stops and idling losses", caused by easily recoverable equipment stoppages or idlings that are not usually recorded in daily reports, and "speed losses", resulting from the difference between the equipment's design speed and its actual operating speed.

Performance losses are often hidden and hard to identify; therefore, it is necessary to identify and quantify the loss through calculation.

（3)  Defect Loss

Defect loss is often considered to be only the waste of raw material cost from producing defective product/semi-finished-product (the defects). But in the context of equipment loss, the focus is on the time loss incurred from producing the defects. The loss related to the raw material cost itself is considered material loss.

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●Author profile

Nobuhiro Otsuka, Chief TPM Consultant

After joining the Japan Institute of Plant Maintenance (JIPM), Nobuhiro has been working on projects to improve productivity, reduce costs, and improve quality in the metal products, electrical and electronic parts, automotive, food and beverage, pharmaceutical and medical products, and paper industries. Nobuhiro provides consulting support from both a Gemba (shopfloor) perspective and a management perspective. Supports many companies both domestically and overseas. Currently works on a wide range of projects including TPM, cost management/cost reduction, quality improvement, industrial engineering, factory layout planning, purchasing/procurement, etc.

Katsunori Kanegae, Chief TPM Consultant, Director of TPM Consulting Business

After working as a production engineer at an electrical manufacturer, Katsunori became a consultant. As an expert in production strategy, production methods, and equipment management, he has been supporting domestic and international manufacturing companies in productivity improvement, cost management, defect reduction, inventory reduction, and lead time improvement projects. His expertise extends to researching advanced equipment maintenance technology and working on digital transformation in equipment maintenance. He also has authored numerous articles on digital transformation.

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