过程控制
As described above, this alternative to backflushing has a self-correcting property: the shop-floor stock is always related to a certain production order, onto which all the consumed materials were actually issued. On the other hand, backflushing by its very definition can never be self-correcting and should only be used when corrections are rarely needed. An objection can be made with the above described alternative that scrap is not reported with a reason code, or broken out separately from other forms of non-standard usage. But how accurate is scrap reporting in an environment without inventory accuracy? Better to settle for inventory accuracy and worry about scrap later as a separate issue. Option: implement a separate scrap analysis protocol unrelated to inventory transactions. Scrapped parts are segregated for subsequent inspection, quality data recording and possible rework. In both cases, scrapped parts are already removed from inventory at the end of the manufacturing cycle (presumably by returning fewer components to stores). Therefore, an inventory transaction is only needed when parts are deemed acceptable upon inspection, or after a rework operation is performed. Scrap reporting can also be done by using data from the Process control system and/or Manufacturing Execution System. Usually such a system exists to some degree in any firm, even if it is not called PCS or MES and even if it is used eventually only for keeping data regarding personnel performance and piecework, as a basis for calculating the salary of the workers. Such a system could be extended so that each worker reports also the scrapped parts.