3 . Subordinate every other decision to the bottleneck -
Those resources that are not bottlenecks have (by definition) some extra capacity. Use that capacity to
- Letting the non-bottlenecks help the bottleneck or take over some required but low value adding work.
- Everybody works at the pace of the bottleneck, no faster no slower, to avoid overloading the bottleneck with work in progress.
- Those in front of the bottleneck ensure that the buffer of work for the bottleneck is always filled, but not too much.
- Those after the bottleneck ensure that they have some slack to deal with variations in output of the bottleneck.
- Non-bottlenecks ensure that only high quality work in progress handed to the bottleneck.
4 . Elevate the bottleneck
Invest resources and time to improve the performance of the bottleneck, so as to increase their output (and thus the output of the system)
- Adding more people or machines
- Training and mentoring
- Better tools, faster machines
- Switching to a different technology
5 . Return to step 1 - Do not let inertia become the constraint.
The inevitable result of the first four steps, and the reason this is a “continuous” improvement method, is that the constraint moves somewhere else. This step insists that you start back at the beginning, and don’t let inertia become the constraint.
Make a list of all active projects in the company or department, and cross off half of them, strictly prohibiting any work on the inactive projects until further notice.
As WIP drops, the least constrained resources will start to run out of things to do. This is a pivotal moment — you have to avoid the temptation to either “load up” these resources with new tasks, or fire them as “excess capacity.”
As unconstrained resources hold off on starting new projects, they will start sending less work to the constraint, causing throughput to go up. This is the lightbulb moment — when nearly everyone works less, and the company as a result produces more. It is not difficult at this point to convince everyone that their job is to do whatever it takes to maximize the constraint’s productivity, instead of working as many hours as possible.