OEE (Overall Equipment Effectiveness)
The Overall Equipment Effectiveness
(OEE) is a method to get a grip on the productivity losses of a production line
and is based on a structured measurement of these losses. It is an indispensable
tool in a Six Sigma, TPM or SMED project and in 'asset management'. The basic
idea is, that the productivity of a machine or a production line is affected
by several groups of causes of a total different nature, the so-called ‘six
big losses’ :
1. Set-up time
2. Break down time
3. Reduced speed
4. Short stoppages
5. Process waste
6. Reject of products (QC)
Loss 1. and 2. result in
the so-called availability factor of the machine, loss 3. and 4. result in the
speed rate, loss 5. and 6. result in the quality factor. The root causes of
these 6 categories of losses are of a totally different nature, and therefore
require different strategies to tackle them in an improvement project.
Two categories of losses
have been added to the six big losses. These two categories are related to the
machine planning and the logistics, resulting in the so-called planning factor:
a. The machine cannot be used because of a maintenance overhaul or because there
are no orders (insufficient sales)
b. The machine should be producing, but there is no material, or there are no
operators, or no detailed information on the orders is available (flaws in planning
and logistics).
The Figure below provides an overview of the OEE system.
For more information on the OEE, see also the TPM page.