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Slowing Down to Speed up

Apple press machinery

It was great to hear the enthusiasm of David Hall explaining he had convinced the team at Cedenco to slow down the infeed to the apple peelers which resulted in an increase of 6% of throughput through the peelers.

I have seen this apple peeler myself during my last visit to the Cedenco operations in Hastings and it is such an illustrative example of the Theory of Constraints that it would be a shame not to share:

The infeed places the apples in a massive bath and the current ensures that the apples bob along via a grader to the peelers. Once they arrive at the peeler, several ‘one-apple” elevators raise the apples out of the flume to the peeler. However, when the flume delivers more apples than the peeler can handle, this water bath becomes choked with apples that all jostle for a spot on the elevator. As a result of this scramble, several apples would push each other out of the way and the elevator would go up empty. After slowing down the in-feed to create a balanced flow, the apples no longer jostle for a place on the elevator and nicely hop into the elevator one after another. So, a slowing down of the infeed ensures that the peeler receives more apples than before. Overall line performance improved, by slowing down.

Similar to a choked motorway, slowing down traffic or restricting on-ramp vehicles results improves traffic flow. Slowing down to speed up.

When David excitedly mentioned the client’s achievement during our team meeting, Geerten added another example of the Theory of Constraints in action in a powder canning facility. They observed that when the density of the powder reduced, it would take longer for each can to fill. Since these cans were on a fixed-time rotational filler, cans would go around the rotational platform twice if not filled to weight, effectively blocking one of the filler heads. This example shows how a slight change in the property of the product -the density in this case- can create a massive backlog if the system as a whole is not adjusted. So, again, a slight reduction in the rotational speed of the filler will ensure an overall gain in productivity of the canning facility.

Classic Theory of Constraints indeed. At times this is counter-intuitive: slowing down to speed up. It requires you to study your process following a known best practice method. The resulting increase in productivity often feels like ‘magic’, but it’s basically a good process.

Are you able to share an observation where a slowing down of one part of the system removed a bottleneck and thus enabled the whole process to speed up?

About the author: Dr. Liddy Bakker is the Director of Knowledge Management and a founder of Productivity People