How Effectively Are Losses being Tackled? A 4-Level Assessment

Table “Assessing the OEE Level” shows a scheme for assessing the level of control being exercised over the major equipment losses.

Level Item	Level 1 (Losses are not even being monitored)	Level 2 (Facts are being ascertained)	Level 3 (Improvements, backed up by theory, are being implemented)	Level 4 (Losses have been minimized)
1. Break- down Losses	1 Sporadic breakdowns have not been distinguished from chronic ones. 2 More breakdown maintenance is carried out than preventive maintenance. 3 Breakdown losses are high. 4 No Autonomous Maintenance system is in place. 5 The service life of parts varies widely. 6 The weak points of the equipment are not known.	1 Sporadic breakdowns have been distinguished from chronic ones. 2 The ratio of breakdown maintenance to preventive maintenance is about fifty-fifty. 3 Breakdown losses are still high. 4 An Autonomous Maintenance system is being installed. 5 The service life of parts is being estimated. 6 The weak points of the equipment have become obvious. 7 These weaknesses are being addressed through corrective maintenance.	1 A time-based maintenance system has been established. 2 The level of breakdown maintenance has fallen below that of preventive maintenance. 3 Breakdown losses have fallen to 1% or lower. 4 The Autonomous Maintenance system is working well. 5 The service life of parts is being extended.	1 A condition-based monitoring system has been established. 2 Preventive maintenance is predominant. 3 Breakdown losses are between 0.1% and zero. 4 The Autonomous Maintenance system is being sustained and improved. 5 The service life of parts is predicted. 6 New equipment is designed for reliability and maintainability.
2. Change- over Losses	1 The situation is uncontrolled, and everything is left up to the operators. 2 Confusion reigns, and changeover times vary widely.	1 Internal and external tasks have been separated, and standard procedures have been established for these. 2 Times still vary. 3 The next issues to address have been identified.	1 Ways of externalising internal tasks are being sought. 2 Adjustment mechanisms are well understood, and action is being taken to eliminate it.	1 Single-minute changeovers are common. 2 Adjustment has been eliminated, and defect-free products are now turned out from the word ‘go’.
3. Speed Losses	1 Equipment specifications are unclear. 2 No product- specific or machine-specific speed standards have been set.	1 Speed-loss-related problems (mechanical and quality-related) have been identified. 2 Tentative speed standards have been set for each product, and are being sustained. 3 Speeds are fairly consistent.	1 Mechanical and quality problems are being addressed. 2 Speeds have been set for particular products, and the causal relationships between speed problems and the structure of jigs, tooling, etc. are being determined. • Relationships between product quality characteristics and the precision of each section of the equipment have been assessed. 3 Speed losses are low.	1 Improvements to the equipment have enabled it to operate at or above the speeds originally specified. 2 Definitive product- specific speed standards have been set and are sustained. 3 There are no speed losses.
4. Minor- Stop Losses	1 Everything is left to the discretion of the operators, and nobody knows how serious the minor-stop losses are. 2 The situation is unclear, and the location and frequency of the minor stops vary widely.	1 Minor stops are being quantified, with a focus on: • Where the problems arise, and how frequently. • The extent of the losses. 2 Phenomena are stratified and their mechanisms are analysed, and actions are being taken on a trial-and-error basis.	1 Minor-stop problems are itemised and targeted for countermeasures, with positive results.	1 Minor stops have been eliminated, making unattended operation possible.
5. Quality Losses (including startup yield losses)	1 Chronic quality defects are largely neglected. 2 Although some countermeasures have been devised, they are not proving effective.	1 Chronic quality problems are being quantified, with a focus on: • How the problems arise, and how frequently. • The extent of the losses. 2 Loss-causing phenomena are being stratified, the mechanisms by which they occur are being analysed, and solutions are being implemented.	1 Problems giving rise to chronic quality defects have been identified and addressed, with positive results. 2 In-process detection of quality defects is being researched.	1 Quality defect losses are between 0.1% and zero.