This is based on the theory of constraints, where the focus is on bottleneck operations.
You need to make your bottleneck’s operations as efficient as possible to maximize its output.
General efficiency improvement campaigns do not work; they have to be focused on just the bottleneck.
Improving the efficiency of upstream operations only increases the backlog in front of the bottleneck, which increases the investment in inventory.
This can be a major concern in the sales department, depending on the process flow within it.
There needs to be a buffer in front of the bottleneck, to ensure that the bottleneck is always running. This means that a pile of inventory in front of the bottleneck is a good thing.
Only release inventory into the production operation in sufficient quantities to maintain the inventory buffer and maximize the workload at the bottleneck.
Having some sprint capacity in upstream operations is needed to rebuild the buffer quickly, in case it is ever depleted. Otherwise, the bottleneck may be short of work.
Focus on maximizing the throughput per minute passing through the bottleneck. This maximizes profits for the business.