Continuous process manufacturing has traditionally been based on a just-in-case philosophy – inventories of raw materials are maintained just in case some items are of poor quality or a key supplier is shut down by a strike. Subassembly parts are manufactured and stored just in case they are needed later in the manufacturing process. Finished goods are completed and stored just in case unexpected and rush customer orders are received. This philosophy often results in a push approach in which raw materials and subassembly parts are pushed through each process.