OEE Calculation #3: Availability, Performance and Quality
Assume Machine A is a single product machine and is
theoretically capable of producing 1,000 units every hour.
In a 16 hour scheduled production day (e.g. 2 x 8 hour shifts)
Machine A could theoretically produce 16,000 good units.
On a particular day the equipment/process recorded downtime of 2 hours
(e.g. equipement breakdown, waiting on materials etc..)
Scheduled Production Time = 16 Hrs (2 x 8Hr Shift)
Downtime (Planned & Unplanned)= 2 Hrs
Available Time (Uptime) = 16 Hrs - 2 Hrs = 14 Hrs
Available Time / Scheduled Time = 14Hrs/16Hrs = 88% Availability
In this example we will record throughput on the equipment/process
as 12,632 units (cycles) for the 14 hrs of Available Time. Also remember
that the Machine can produce 1,000 units an hour
Available Time = 14 Hrs
Total Product Produced (Throughput) in Available Time = 12,632 units
Theoretical time to produce 12,632 units = 12,632/1,000 = 12.63 Hrs
Theoretical Time / Available Time = 12.63Hrs / 14Hrs = 90% Performance
Out of the 12,632 units (cycles), it was found that only 12,000 of the
units were deemed good units (i.e. shippable units). The other 632 are
accounted as scrapped and/or rework cycles to make shippable.
Performance Time = 12.63 Hrs
Availability x Performance x Quality = 88% x 90% x 95% = 75% OEE
Good Units (expressed in time) = 12,000 units / 1,000 per Hour = 12 Hrs
Good Units (expressed in Time) / Performance Time = 12Hrs / 12.63 Hrs = 95% Quality
Therefore there are losses totalling 25% for the day
(equating to 4 production hours lost).
OEE is about looking at the root causes compiling the 25%,
and taking corrective action to reduce the losses and increase the OEE %