**Q: When a batch is running at the moment when a new shift-crew comes in, we do not know how much volume was produced yet in that batch. How do we determine an accurate OEE now?**

# Batch production

- We are running a 5 shift operation in a fixed schedule.
- Our machine throws out product in bin’s.
- When a bin is full, it weight is determined by placing it on a scale while a new bin is placed.
- It takes between 30 and 90 minutes to fill a bin.
- The maximum output is 10KG/Min
- At the end of a shift usually a bin is still being filled and the leaving crew cannot tell yet how much output there was produced for the running bin.
- The next shift will take this bin and weigh it.

So for a bin it might look like this:

**Early shift:**

Starts bin

Runs 30 min

Theoretical Output 30×10=300KG

Actual output 250 KG

Output measured 0 KG

**Late shift:**

Removes and weight bin

Runs 40 min

Theoretical output 40×10= 400 KG

Actual output 300 KG

Output measured 550 KG

## The problem:

- If the early shift enters 30 minutes and 0 KG, their OEE is a bit too low, which is not a real problem.
- If the late shift enters 40 minutes and 550 KG this creates a problem, since this volume is created during 70 minutes and not in 40.
- In 40 minutes they could have only produced 400 KG, thus 550 is not possible; it would top over the performance rate.

Of course in the long term it would -more or less- level out, since every shift loses some in the end of the shift and gains some in the beginning, but it is not accurate.

**How do we measure an accurate OEE in this situation?**

Arno Koch • Whenever batch-runs exceed the shift-duration, while at that moment the volume cannot be determined, we have to stretch the definition of ‘a shift’.

In the example above, a solution could be: **Defining that the last bin that has been started at the end of a shift belongs to that shift**.

This means:

The new shift measures the bin, adds the volume ánd production time to the (still measuring) previous shift and now start the new shift-calculation.

The registered shift start-time ánd end-time will now usually will be a bit later than the actual start- and end-time of the crew.

Also the shift duration may now be variable, so in this case sometimes a bit less or more than 480 minutes. This is not a problem; now there will be an accurate OEE calculation per shift ánd per longer period of measured time.

See also: