SAPMRP详解参考模板.doc
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在文西的鼓励下开始着手准备写一点MRP的东西，本想着其实也不会太难吧，可是越到后面越艰难丫，MRP博大精深，但是要做到狠精确是不能的，要不我们自己的饭碗都没得鸟，本着这个伟大的精神，文西们开始了其实有一部电影叫：……文西VS文西……MRP流程可分为两种处理方式：基于消耗的计划、物料需求计划（MRP），而基于消耗的计划可有三种处理方式：consumption-based planning可以手动，也可以自动（系统根据预测自动计算出来）Reorder point planningTime-phased planningForecast-based Planning这三种处理方式都是基于物料消耗历史数据的，唯一有一点区别的是时间段计划，根据历史值预测估算未来需求的时候，只根据预先定制好的具有特殊规律的时间间隔来计划运行基于消耗的计划不参照生产计划，换言之，净需求计算不会被独立或非独立需求触发，其要不就被可用库存水平低于再订货点触发，要不就被预测根据历史数据计算需求而触发一般情况下只有低于再订货点，在Reorder point planning时输入计划文件（planning file Entry），这时才会触发净需求计划，为了避免计划过剩，销售订单、预留等不包含在净需求计算中，但在特定的环境中要考虑在Reorder point planning的净需求计算时同样必须考虑外部需求，你可以让销售订单、预留等外部需求包含在内。
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如图：在此定义工作时间，到点自动运行如由于任何原因造成background job (PROFILE)终止，则要手动从program RMMM0001建立一个后台工作，输入项目名 RMMM0001 然后点击闹钟执行 ，再一次执行之后，会有一个消息通知你物料已改变如图：其创建的更改记录可在此看： 点击执行2、净需求计算(书本上讲的很粗略，也没有具体例子，这是我在yahoo上搜到的，供参考)FOR EXAMPLE:The Master Production Schedule shows we have to make 400 scissors during the 3 rd week, in the 4 th week 600, in the 6 th week 800, and in the 7 th week 300 scissors.We will name (GR) Gross Requirements to the demand of fabrication of the products, the final products (in this case the scissors) correspond to the quantity appeared in the MPS. To the intermediate products (in this case the screws) you have to multiply the necessary quantity to make the final product with its demand. Gross Requirements of the MRPInventory Master File The file indicated us that we have since the first week 550 scissors in stock, also it indicates that the security stock do not have to be less than 50 scissors.We will name Availability (A) to the initial stock of the final product we have to satisfy the before mentioned necessities.We Will name Security Stock (SS) to the final quantity of the final product that cannot be use to satisfy the necessities.We will denominate Net Requirements (NR) to the quantity that we really need to satisfy the Gross Requirements (GR), taking into account the Availability (A) and the Security Stock (SS), the calculations will be the following:1. If the availability is more than 0 , NR = GR-A+ SS 2. If the availability is equal to 0 , NR = GR Net Requirements of the MRP Week 1: Gross Requirements are invalid, the availability is of 550 units, inside the security stock is 50, and therefore if we do not have Gross Requirements there are not also Net Requirements.GR = 0 A= 550, SS = 50 NR = 0Week 2: the same as the week 1, so we have an Availability of 550 units and the Security Stock is 50 units.Week 3: The Gross Requirements are 400 units, but we have an Availability of 550 inherited of the last week, so we can satisfy the 400 units with the 550 available and we make sure that 50 we have 50 units for the Security Stock.NR = GR- A + SS; NR = 400- 550 + 50; NR = - 100It is important to realise that the result is negative, that means that we do not need to make more scissors, because there are 150 available. 550-400 = 150Week 4: We need to make 600 scissors but we only have 150 units that were left the weeks before, so the Nets Requirements are:NR = GR- A + SS; NR= 600-150+50; NR = 500We have to make during the 4 th week 500 scissors; we ensure that the Security Stock has 50 units.Week 5: The GR are invalid, we do not need to fabricate more because the NR are also invalid.Week 6: The Gross Requirements are 800 units, the Availability is invalid so,NR= GR, NR=800We have to fabricate 800 units during the 6 th week, and our security stock is 50 units.Week 7: The same as in the week 6, our Net Requirements are 300 units,NR= GR, NR=300Net Requirements of the MRP 其实这个例子很简单易懂，运用两个公式算净需求：1. If the availability is more than 0 , NR = GR-A+ SS 2. If the availability is equal to 0 , NR = GR 3、replenishment lead time:包括三个部分，如图：其中采购处理时间没有在主数据中，在这里设置：而计划交货时间和收货处理时间在物料主数据中的MRP2视图中：4、让外部需求也包含在重订货点计划中： 5、计划运行 。
