Consultants and Mentors in World Class Manufacturing

What is OEE?


Overall Equipment Effectiveness is what it says on the tin, it is a measure of how effective an equipment is at producing good product when required.

It is the ratio of the amount of good product produced divided by the potential amount of product that could have been produced in the planned operating time, including breakdowns and other losses expressed as a percentage.


OEE monitoring is very useful to prioritise what you should focus attention on at the coalface, but it is NOT an absolute performance measure.


OEE = Availability x Performance x Quality


There are six types of losses that contribute to this OEE measure:


Availability          Set up and initial adjustment losses / Breakdown losses

Performance      Idling and minor stoppage losses /   Speed losses (Cycle time losses)

Quality                Start up quality losses / In process quality losses


Availability losses are most easily measured by recording set up and breakdown time. Performance losses must be calculated by comparing output to maximum achievable in the time that the machine runs. Quality losses must be recorded by measuring scrap / rework or comparing good output to input.


When you have measured the six losses, you will usually find that one loss is much greater than the other five, and this enables you to focus on one type of loss by deploying the appropriate skills for that type of loss. This is a well trodden path to performance improvement so stick with it.


You do need to take care however to only use OEE for local improvements because 1% improvement with an order backlog is worth more that 1% improvement where you can fulfil customer and stock orders within your working pattern. 1% improvement on a constraint machine is worth more than 1% on a non constrained machine.


Finally 1% quality loss at the start of a process may have a different value to 1% quality loss at the end of the process.


Want to learn more? Keep visiting the TPM++ web site, or call me on 077669 10835

Brian Burgess, Principal Consultant, TPM++  brian@tpmplus.co.uk