# x Measuring batches that run beyond the shift-limit

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 measure the batches to 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.