生产管理系统包含生产计划，生产执行，生产核算三个方面。通常情况下生产计划和生产核算属于ERP的范畴，生产执行更多的是属于MES范围。Odoo作为现今最大的开源ERP软件，它更像是一个平台，通过安装组合不同的插件，可以实现生产管理系统全方面的功能。
The production management system includes three aspects: production planning, production execution, and production accounting. Usually, production planning and production accounting belong to the scope of ERP, and production execution is more of the scope of MES. As the largest open source ERP software today, Odoo is more like a platform. By installing and combining different plug-ins, it can realize all aspects of the production management system.

对生产计划来说，核心就是MRP，一般MRP原理比较简单。比如说我接到一个销售单A产品1万件，根据BOM表，A产品包含半成品BCD，就需要半成品BCD各1万件，BCD可能有一定的库存，根据缺口量=需求量-库存量，系统就会根据缺口量就会自动生成相应的采购建议单，那么采购部门的员工看到后就会联系供应商下单，收到货后由车间领料进行生产。
For production planning, the core is MRP, and the general MRP principle is relatively simple. For example, I received a sales order of 10,000 pieces of product A. According to the BOM table, product A contains semi-finished products BCD, so I need 10,000 pieces of semi-finished products BCD, and BCD may have a certain amount of inventory. According to the gap = demand - inventory, The system will automatically generate a corresponding purchase proposal based on the gap amount, and the employees of the purchasing department will contact the supplier to place an order after seeing it. After receiving the goods, the workshop will pick materials for production.

但在实际生产过程中，运行MRP时会遇到很多问题，当将所有问题都考虑进去时，MRP就变得很复杂了。不同的ERP类软件，对于不同类型的问题的支持程度是不同的。比如SAP可能各种情况都会考虑的较好，可以通过一些不同的配置来实现不同程度的支持，但像金蝶，用友，可能更多的是一个标准的MRP，各种细节不能全部支持到，就显得不是那么适合了。在odoo中，针对不同的问题，它更多的是通过安装不同功能的插件。那么通常MRP运算当中需要考虑什么问题呢？
But in the actual production process, there are many problems when running MRP, when all the problems are taken into account, MRP becomes very complicated. Different ERP software has different levels of support for different types of problems. For example, SAP may consider various situations better, and can achieve different levels of support through some different configurations, but like Kingdee and Yonyou, it may be more of a standard MRP, and various details cannot be fully supported. It doesn't seem so suitable. In odoo, for different problems, it is more about installing plug-ins with different functions. So what issues need to be considered in the MRP calculation?

1. 多单位 multi-unit

通常常见的问题就是多单位，包含两种情况，
Usually the common problem is multi-unit, including two cases, 

2. 替代料  Alternative materials

在电子行业比较常见替代料的问题。比如生产某个电容器，可以使用进口和国产两个品牌，可能进口品牌的质量较好。正常情况下，工厂使用进口品牌生产。但对于有些情况，比如国际关系变化，使得进口品牌不容易采购到了，或者某一销售单的价格比较低，工厂希望可以降低成本，这时就需要使用国产品牌来替代。我们可以通过设置某些条件使系统能自动处理，当进口件有库存时，系统优先使用进口件，进口件没库存，或某些情况采购不到时，系统自动提示采购国产替代件。因为如果人工修改采购单会引起一系列的问题，也增加复杂性和工作量。
The problem of substitute materials is more common in the electronics industry. For example, in the production of a capacitor, both imported and domestic brands can be used, and the quality of imported brands may be better. Under normal circumstances, factories use imported brands for production. However, in some cases, such as changes in international relations, it is difficult to purchase imported brands, or the price of a certain sales order is relatively low, and the factory hopes to reduce costs. In this case, domestic brands need to be used instead. We can set certain conditions to enable the system to process automatically. When the imported parts are in stock, the system will give priority to the imported parts. When the imported parts are out of stock, or cannot be purchased in some cases, the system will automatically prompt to purchase domestic substitute parts. Because manually modifying the purchase order will cause a series of problems, but also increase the complexity and workload.

3. 最低采购量 MoQ

MoQ，最低采购量。比如某产品缺口量是60，但供应商最低采购量是100，此时系统要采用最小采购量跑出采购建议单。
MoQ, minimum order quantity. For example, the shortfall of a product is 60, but the minimum purchase quantity of the supplier is 100. At this time, the system needs to use the minimum purchase quantity of 100 to run out the purchase proposal.

4. 整包装 whole package

整包装。比如采购电线，缺口量160米，但采购时，整包装是100米，系统跑出整包装的采购建议单。
Whole package. For example, when purchasing wires, the gap is 160 meters, but when purchasing, the whole package is 100 meters, and the system needs to run out the purchase proposal form for the whole package.

5. 经济生产批量 Economic Production Quantity

比如在电子行业SMT贴片生产行业，计划生产某型号的电路板，生产一件电路板和生产100件电路板的成本差不多，如果缺口量60个，实际生产时最好是按100去生产，因为100是它的经济生产批量。系统跑出的生产单应该是经济生产批量而不是缺口量。
For example, in the SMT patch production industry, to produce a certain type of circuit board, the cost of producing one circuit board is similar to that of producing 100 circuit boards. If there are 60 gaps, it is best to produce 100 in actual production, because 100 is Its economical production batches. The production order issued by the system should be the economical production batch rather than the gap.