SAP bill of materials analysis
IT 168 informatization
First, the importance of product structure-BOM
BOM (bill of materials) is called bill of materials, also called product structure table, bill of materials, etc.
Disassemble the raw materials, parts and assemblies of the products, record the materials according to the order of the manufacturing process, such as material code, product name, specification, unit consumption, loss, etc., and organize them into a list, which is the bill of materials, that is, BOM.
The BOM is:
(1) the basis of MRP.
(2) Calculation basis of manufacturing orders.
(3) In essence, it is an engineering document, which is not only the product specification, but also the basis of the manufacturing process.
(4) The accounting basis of product cost.
From the above, we can see that the importance of BOM and its influence range are very large, so its content must be kept correct and timely at any time.
Second, the main points of establishing product structure
(1) BOM must be able to display the manufacturing hierarchy.
(2) BOM must avoid ambiguity.
The BOM must be able to display the manufacturing level.
An ideal BOM should not only show the composition structure of the product, but also explain the stage of the product in the manufacturing process. In other words, the BOM must define products from the manufacturing level, each level represents the completion of a step in the process, and each inventory item has the action of entering and leaving the warehouse at the upper and lower levels of the BOM.
BOM must avoid ambiguity.
The unity of homework is the key. After assembly, a batch of components are independent and complete units, and are sent to the inventory or the next workstation, so it is necessary to define a material number for this component. If an item is not defined, MRP will not be able to generate the necessary orders for this component.
Third, the system file design of product structure
Although there will be many levels of product structure, we only need to maintain the parent-child relationship in the system, and then we can get the product structure with multi-level relationship through series connection.
The above is a four-level BOM. In the BOM table of ERP system, the complete BOM of X product can be obtained only by establishing the related parent-child relationship. As can be seen from the above figure, the substructure of the upper structure becomes the parent structure of the lower structure, and the BOM can be divided into many types.
(1) bill of materials for production
(2) sales BOM
(3)BOM； Used for packaging materials;
(4) customs BOM.
1, production bill of materials
In addition to explaining the parent-child relationship, there are the following necessary fields, which are explained as follows:
(1) serial number
Due to different processes, different validity periods or different plug-in locations, there may be multiple sub-items under each parent item. This situation cannot be explained by unit consumption, and the parent-child items may not be unique, so the same parent item is described by a unique serial number. Because of the nature of the materials or the order in which the materials are distributed, it is required to arrange the items in a certain order, which is also realized by serial numbers. When the BOM is expanded, it is also arranged by serial number.
(2) unit dose
A child that indicates how many inventory units are needed for each inventory unit parent. The inventory unit of the material is defined in the material code data table.
(3) Cardinality
Indicates the quantity of the parent item. For example, each carton (material code A) can hold 100 watches (X), as shown in the BOM:
Parent: X serial number 1 child: A unit dose: 1 base: 100.
(4) Loss rate
For some materials, due to machinery, equipment or assembly, the normal unit consumption can not meet the production needs. , and should define the percentage of loss rate.
(5) Fixed loss
According to the loss rate, the loss of different orders is different, the loss of small orders is also small, and the loss of large orders is also large, but sometimes even small orders need a certain loss, which can be defined by fixed loss. That is, no matter how many orders, there must be at least so many losses.
(6) Effective date and expiration date.
Due to engineering changes or different product structures in different periods, it is necessary to specify effective date and expiration date. If it is always valid, do not specify the expiration date, or specify a very large date, or let the expiration date = "1900/11".
(7) Issue process number
Each parent material defines a routing in the material code company data table, and each routing needs to define at least one operation or multiple operations in the routing data table. When issuing materials, different BOM sub-items may be sent to the same operation or different operations. Which operation should be sent when issuing materials? When creating a production order to generate material details, if the operation number is not specified in the BOM, the first operation in the routing data table is regarded as the issuing operation.
(8) country
There are three statuses of BOM: to be confirmed, confirmed, and canceled adding BOM sub-items. Only confirmed sub-items can be used. You can cancel the items to be confirmed or confirmed as ok.
(9) Customer quotation mark
It means that this sub-item is the material provided by the customer, and the cost of this material is not considered in the cost calculation.
(10) manufacturer
Some materials under the parent project require that a certain brand must be used. Please indicate the brand manufacturer here, which can be used as a reference when placing purchase orders and distributing production materials. Even if the manufacturers are different, you can simplify the material management and reduce the material substitution relationship without defining a new material code.
(1 1) plug-in location
Indicate the placement position of the subitem in the parent item, for example, place a capacitor at P 1 1 on a circuit board, indicating that the insertion position is P 1 1.
(12) starting batch number
Sometimes a sub-item in the BOM is only used in the specified batch number, and it is invalid in other batches. It can be explained by the starting batch number and the ending batch number.
Please note that batch number control is only required in the following cases:
(1. When the product or material has a shelf life;
(2) If the product has special requirements or the printing and packaging are different without adding new models, try not to use batch number control.
(13) End lot number
Please refer to the starting batch number above.
(14) Remarks
For explanatory purposes only.
2. List of sales materials
Also known as sample BOM, that is, parts list, it only describes the parts list and standard unit consumption of a finished product (model), with only one-layer structure and no manufacturing information. Its sub-items are mostly the lowest-level parts, and may also be standard assemblies or semi-finished products.
However, components or semi-finished products are no longer expanded in the R&D BOM, and they are regarded as parts. When quoting products, refer to the standard cost of sales BOM materials.
3. Packing bill of materials
Some companies' finished products need to be packaged according to customers' requirements, so even the same model needs different packaging materials and different packaging processes because of different customers, different orders and different batch numbers.
If the part is put into BOM for production, a large number of finished material codes need to be generated. Therefore, separating this part and using the same finished material code with different customers, orders and batch numbers can reduce many finished material codes.
This is not necessary. If the packaging changes little or there are not many models, the packaging materials can be put into BOM for production. The BOM structure of packaging materials is roughly the same as that of production, with the following fields added:
(1) customer code
If specified, this subitem can only be used for the specified customer; If not specified, all customers can use this subitem.
(2) Order code
If specified, this subitem can only be used in the specified order code; If not specified, it can be used in all orders.
(3) Batch number
If specified, the subitem can only be used in the specified batch number; if not specified, the subitem can be used.