In order to get the most from a two-level MPS system, a continuous improvement approach using JiT and TQ concepts has to be implemented to obtain the best-possible flexibility on the physical flow [19]. An important point will be the necessary adaptation of some tools of classical “JiT” to the diversity of products, as for example the use of the concept of “generic Kanban” in place of the classic Kanban reserved for “high repetitivity/low variety” production.
One of the mechanisms contained within JiT for the transformation of an ordinary environment into a short lead time environment is Kanban logic used to pull production forward [20]. But if several hundred references exist or if demand for these products is irregular, then producing what has just been consumed will create stocks, because consumption is not repetitive. Furthermore, the use of several hundred specific Kanbans will overburden the work shop with a lot of cards and containers.
The best solution to pull production forward in this case is to use generic Kanbans, where each Kanban represents an available physical area for work in process, whatever the reference that has to be manufactured.
With a generic Kanban, MRP2 gives the references to be manufactured, by using a MRP calculation, or by using the MPS, or by the orders themselves.