Case study

Now that the orders are entered correctly, this delay issue has been solved. During the production of another order, however, there are 10 unplanned stops on the line (totalling half an hour). The operator thinks he knows what the problem is, which is that one of the six nozzles is blocked; a common problem when the line is running at full speed. After flushing all six nozzles, the line usually runs again. On the next order, the operator decides to run the line at a slower speed to avoid the short stops.

It is true that the nozzle is causing the downtime in some cases. But a second problem comes to light, namely the supply of cake moulds. After analysing the digital data, it becomes apparent that the operator cleaned the nozzles six times for no reason because the downtime was due to the absence of pie moulds. While the operator was (needlessly) cleaning the nozzles, his colleague was able to place the correct pie moulds. This meant it wasn't clear that the absence of proper pie moulds was the real cause. After optimising the supply, the production line has far fewer unplanned stops.

At the start of each new order, the operator takes into account that 50 pies will not pass the quality check. On a third order, one of the operators forgets to take a container with pies out of the oven on time. Consequence: 100 pies are burnt. This results in a lower quality percentage (the number of properly made products divided by the total products produced, multiplied by 100). To meet the order numbers, 50 (start-up rejects) plus 100 (production rejects) more pies are produced.