How to calculate OEE
(Overall Equipment Effectiveness)?

OpEx OEE (Operational Excellence Overall Equipment Effectiveness) is a Business Metric commonly used by the world's leading Manufacturers to increase capacity, reduce costs and drive continuous improvement.

OEE is a closed-loop metric measuring the 3 critical manufacturing components of Availability, Performance and Quality. Your OEE score is presented as a %. See below 2 methods to calculate your OEE % (Top Line OEE calculation and APQ OEE calculation).

OEEsystems International's Smart Factory Software, PerformOEE, is used globally by progressive manufacturers to drive Continuous Improvement and culture change underpinned by our Science of Manufacturing Methodology.

Availability %

The Process's Actual operating time as a percentage of Scheduled operating time. This is often referred to as Uptime or Runtime.

Performance %

Based on Process throughput, Performance is a measure of expected time to produce throughput (Process Capability) compared to Availability time.

Quality %

The total Good Units produced as a percentage of the Throughput. Also referred to as First Pass Yield (FPY).

How to calculate OEE
(Overall Equipment Effectiveness)?

Availability x Performance x Quality = OEE %

Top Line OEE Calculation
Actual Good Output compared to Capable Output

Assume Machine A is a single product machine and is
capable of producing 1,000 units every hour.

In a 16 hour production day
Machine A is capable of producing 16,000 good units (Capable Output).
i.e. Capable Output = 1000 units x 16 hours
= 16,000 good units

If on one particular day, Machine A produced
12,000 good units (Actual Good Output) then our OEE would be:

Actual Good Output / Capable Output

Top Line OEE = 12,000 / 16,000
= 75% OEE

Therefore, there are losses totaling 25% for the day.
OEE Losses = 100% - OEE% =
100% - 75% = 25%
Lost Capacity = Capable Output x 25% =
16,000 x 25% = 4,000
Lost Time = Production Time x 25% =
16 hours x 25% = 4 hours

Continuous Improvement is about looking at the root causes compiling
the 25% and taking the agreed actions to increase the OEE%.

Good Units Produced / Capable Output (for the scheduled production time)

APQ OEE Calculation
A(vailability), P(erformance) and Q(uality)

Assume Machine A is a single product machine and is
capable of producing 1,000 units every hour (Machine Capability).

In a 16 hour scheduled production day
Machine A is capable of producing 16,000 good units.

On a particular day Machine A recorded downtime of 2 hours
(e.g. equipment breakdown, waiting on materials etc..).

Scheduled Production Time = 16 Hrs
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
Machine Capability Rate = 1000 units per hour
Total product produced (Throughput) in Available Time = 12,632 units
Machine Capability Time to produce 12,632 units = 12,632/1,000 = 12.63 Hrs
Machine Capability Time / Availability 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
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

Availability x Performance x Quality = 88% x 90% x 95% = 75% OEE

Therefore, there are losses totaling 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 %.

Availability x Performance x Quality = 88% x 90% x 95% = 75% OEE

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