南京工程学 质量管理第7讲 森口体系.ppt

森口体系的涵义 森口体系，更确切地说，是一种生产管理思想，是以丰田准时生产制的合作开发者森口凡一的名字命名的，它与基于统计的质量控制方法相类似，不过在许多方面还存在冲突。 检验方法 森口体系的检验方法 1．判断式检验 指把次品从合格品中挑出来．将有关信息立即反馈到生产该产品的工人那里，然后由该工人进行修理．这种方法有时也叫“质检”。森口认同大家的观点，认为质检不是有效的质量管理方法，应慎用。 2．信息式检验 运用检验中得来的数据控制生产流程，防止次品出现。森口担心，传统的统计式质量管理不能在生产之后即时检查，因此不能提供最好的信息来确定质量问题的起因并用于将来的防错。 3．溯源式检验 在事件发生之前就确认好是否存在进行高质量生产所必需的条件。这就需要在生产之前检查员工的操作条件，而非在生产之后再检查。森口认为，溯源式检验是一种理想的质控手段，因为在生产流程开始运作之前就能获得有关反馈。 SMED 森口数分钟更换模具方式 森口指出，设备调试分内部调试和外部调试两大部分，内部调试必须关机进行，而外部调试则可在机器运行中操作。如果将大家都认为只能通过内部调试进行的各种程序变为外部调试，就能够大大提高运作效率。 Single Minute Exchange of Die ( SMED) Setup reduction (often known as Single Minute Exchange of Die or SMED) is one of the more mundane aspects of Lean Manufacturing and is often ignored. Risk Difficulty Loop When we run large lots of each product, setups on that product are infrequent. Setups take skill, practice and coaching, much like golf. When operators perform setups infrequently they do not learn them well.? This leads to the perception that setups are difficult and risky. (You never know how long it will take or whether the product will be right). The perceptions of risk and difficulty encourages large lots and thus fewer setups. Piece Cost Loop With large lots, a fixed setup cost is amortized over a large number of units. This seems to reduce the unit cost. There are offsetting costs associated with the resulting inventories, but these offsetting costs are usually buried in the overhead. This also encourages large lots or runs. Results The consequence is high inventory and complex scheduling. These give rise to a plethora costs and negative consequences. The black hole of overhead sucks in most of the costs. Other penalties such as erratic deliveries are far removed from the fundamental cause and it is difficult to link cause and effect. Limiting mechanisms prevent lot sizes from going to infinity but these are often weak. The leverage point in this system is in the risk perception loop. If we can make setups fast, easy and predictable the loop reverses i