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1、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 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
2、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 Reorder point Forecast-based Time-phased 可以手动, 也可以自动 (系统根据预测自动计算
3、出来) 售订单、预留等外部需求包含在内。 如图: 而物料需求计划( MRP )与基于消耗的计划则相反 1、要使物料参与 MRP 流程处理,首先要在物料主数据中建立相关 MRP 参数,同时由于 MRP 计划物料众多, 其中有很多物料运用到的参数 具有相通点,因此会涉及到一个MRP 参数文件 MRP Profile,其作用就 是可以将在参数文件中设置好的值直接带到物料主数据的MRP 视图字 段中。 这些参数文件可以创建也可以修改:(用修改示范一下) 选好参数文件后点击此按钮 1:固定值,若将有关字段设成固定值,则在建物料主数据的MRP 视图 时运用 MRP 参数文件,这些字段 Copy过去后不能更
4、改 2:与1相反,即使默认值 copy过去了但还是能再进行更改 3: 相对应的,在固定值和默认值中勾选了多少个字段,在数据屏幕 1、 2中就会显示多少个相应的字段 12 3 同时这个 T-code可以查看 MRP 参数文件的使用情况: 在数据屏幕1 中的字段和值 查询VB01 参数文件,结果如下: 那这些参数文件中的值可不可以改呢,是可以的,改了之后有什么影 响呢例如,改了VB01 这个参数文件的某一个或某些值,系统不仅会自 动在后台创建一个工作 更改用到这个参数 文件的物料主数据,还会自动创建一个物料主数据的更改记录。 如图: 选好参数文件后执行, 也可更精确的查询某一 工厂下,或是某一MR
5、P 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: 在此定义工 作时间,到 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
6、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
7、 case the screws) you have to multiply the necessary quantity to make the final product with its demand. Gross Requirements of the MRP Inventory 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
8、 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 Requiremen
9、ts (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 Req
10、uirements 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 = 0 Week 2: the same as the week 1, so we have an Availabi
11、lity 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;
12、 NR = 400- 550 + 50; NR = - 100 It 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 = 150 Week 4: We need to make 600 scissors but we only have 150 units that were left the weeks before, so the Nets Re
13、quirements are: NR = GR- A + SS; NR= 600-150+50; NR = 500 We 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
14、 Availability is invalid so, NR= GR, NR=800 We 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=300 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.
15、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: Net Requirements of the MRP 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 全部运行 total planning 只跑这一次 single-item planning 看看物料主数据里相关的参数设置: Planning file entry 一般来说,只要在后台激活了MRP ,当建立 MR
16、P 物料的主数据时( MRP view),这个物料就会被自动规划到计划文件中了。所以,当建好一 个物料后,创建计划文件, 系统会提示已存在。它控制运行和运行范 围。运行范围可在此定义: By the way 解释一下三种类型的计划运行: NETCH: net change planning in the total horizon 只要物料供给 或需求之任一数据变更,则执行MRP (前提是在物料的计划文件里设 定了NETCH 标识); NETPL: net change planning in the planning horizon 在计划范 围内有物料有供给或需求之任一数据变更就执行MRP ; NEUPL: regenerative planning 全面执行 MRP ,即将所有物料包含在 计划文件中计划运行。 If a material is not included in the BOM, the highest level (999) is automatically