OEE.pl - Six main losses

OEE - Six main losses

Six main losses	OEE loss category	Examples of events	Comments
Failures	Downtime	Equipment failures Unscheduled maintenance General failures
Setup and changover	Downtime	Setup Startup Changeovers No material No operator
Minor stops	Speed loss	Blocked product flow Blocked component (feeder)	Usually contains only stops lasting longer than 5 minutes and not requirng maintenance personel.
Reduced speed	Speed loss	Unstable run Machine worn down Unefficient operator	Everything what reduces runing speed to lower than maximum availble.
Startup quality rejects	Poor quality	Scraps Rework Damaged in process Assembling faults	Rejects during heat up, start up, wrong settings.
Production quality rejects	Poor quality	Scraps Rework Damaged in process Assembling faults	Regular production rejects

As all 6 main losses and events contributing to them are known it's possible to improve them. Grouping into categories makes analysis much more easy.

Failures:
Eliminating of unplanned downtimes is a critical point for OEE improvement. It's important to know how many, when downtimes occured and what were their root causes. Root causes are connected to apropriate codes, what gives a possibilty to analyze them and find find the ones making the biggest losses.

Setup and changeovers :
Setup and changeover times is the time between the last good part produced before changeover (setup) and the first part produced after changeover (setup). Often it includes additional time for adjustmenst or startup necessary to achive full speed of production. Monitoring of changeovers times is critical for reducing those losses.

Minor stops and reduced speed:
They are the most difficult losses to analyse. A cycle time analysisof cycle time is necessary to reveal them. Minor stops have to be separated from reduced speed run due to completely different root causes of those losses.

Startup and production rejects:
Thise two cetegories should be separated, because there is different source of rejects. Products requiring any repair or rework should considered as rejects. Tracking of the moment in which they are created allows to define root causes what often leeds to discover the pattern of their creation.