Cover-Time Planning/Takt Planning: A technique for materials requirement and production planning

摘要

AbstractCover-Time Planning, or Takt Planning, is presented. It is a system for calculating material requirements and start of purchases and production. Requested production rates of sales items, or alternative prefabricated modules in stock, are “broken down”, exploded, to create the need for components, for all underlying items (articles) in the Bill of Material. Inventory and already ordered replenishments are compared with the item’s desired production rate. How long already made actions are expected to cover the desired expected sales and production rates is compared with the item’s lead time; if a forward future shortage is likely the article is signalled for a refill. With examples is described how make-to-order production is done easily. The method is a type of reorder point system, but with time instead of quantity as decision variable. Unlike a traditional reorder point system increases and decreases of production can be planned. Future work load in various production sections can be estimated. It is described how an “Available-to-promise”-system should be designed and used. Cover-Time Planning (CTP) is a complete alternative to Materials Requirements Planning (MRP). CTP responds faster than MRP, since MRP for each structural level uses a batch size to “break down” and to magnify the need at the underlying level. In the end a large material acquisition needs to be ordered maybe just to build a single end item. CTP uses the end item requirement rates on all structural levels shifted with the lead times, when customer demand changes, the entire production chain react simultaneously.