By Xavier Perrin (firstname.lastname@example.org)
How to improve the flow is such an environment? How to pull production? Generic kanban can be the solution as it allows controlling the flow of orders along the value-stream. Typically, generic kanban allows setting a pull system between process steps. One of the process steps is surely the bottleneck. This bottleneck should pull production from upstream process steps. A kanban loop is set between the bottleneck and the gateway process. Let's start from the bottleneck. One kanban card is associated to each shop-order and it is placed in the shop-packet. Once the order has been processed on the bottleneck, the card is removed from the shop-packet and it is returned back to the gateway process where it is placed on a kanban board. The rule is that the gateway process is authorized to start a new order only when a kanban card is available on the kanban board. Priorities are still given by the dispatch list. Once the operation on the gateway process is completed, the card is placed in the shop-packet and stays in it until the bottleneck process has been passed. In a push system, the only information used for authorizing production is the dispatch-list and corresponding shop-orders. In a pull system with generic kanban, two pieces of information are needed for authorizing production: one shop-order and its relative priority in the dispatch list AND one kanban card. See the value-stream on the next picture:
The following picture shows a kanban board for generic kanban. In the example above, the board should be placed near the turning process:
The next picture shows a container somewhere between the turning process and the grinding 2 process (bottleneck).
Note that generic and specific kanban (for high runners) can work together in the same value-stream.
Note also that generic kanban is an appropriate tool for implementing the TOC's DBR principle.