Shulou(Shulou.com)06/02 Report--

Learn BOM, this article is an excellent material!

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This paper will describe in detail the function of bill of materials (BOM) in static data, combined with CAD (computer aided design), CAPP (computer aided process planning), PDM (product data management), MRP Ⅱ (material manufacturing resource planning), ERP (enterprise resource planning) and so on.

This article will try to explain the common format and management significance of various BOM corresponding files in practice, as well as the suggestions for computer processing.

one

Basic background knowledge

This definition can be used in combination with the national standard document for reference only.

Product: the finished product provided by the manufacturing enterprise to the user or market in the form of commodity

Complete set of equipment: the sum of two or more products that are generally connected without an assembly process in a manufacturing enterprise, but are used to perform interrelated functions.

Parts: a single finished product made without an assembly process

Assembly: a finished product consisting of several parts (parts, sub-assemblies) in a detachable or non-detachable form; sub-components can be divided into level 1 and level 2 according to their subordinate product relationships.

Assembly: a complex finished product consisting of several departments in detachable or non-detachable form, such as engine assembly, axle assembly, front axle assembly, etc., capable of performing certain independent functions; it is composed of parts and components; it may also be called assembly, whole piece, device, whole piece, etc. Complex products may have sub-assemblies.

Module: a unit with relatively independent functions and a general interface. Similar to the assembly, but may be relatively simple.

Special parts (basic parts): special parts for this product. However, in practice, there are often many borrowing relationships, and the actual meaning of special parts is the parts used in this product for the first time.

Borrowing parts: the components of existing products are used in this product, and these components are called borrowing parts.

In general, the direct borrowing of the source product is called a loan. If the product is borrowed in the next design, the borrowing part of the source product is called secondary borrowing. In the process of the second borrowing, it is easy to have the disorder of the borrowing relationship, and the borrowing source product relationship is often mistakenly connected to the primary borrowing product.

General parts: parts that are interchangeable in products of different types or different specifications of the same type. In fact, it is also a kind of borrowed parts, often after the borrowed parts are borrowed for a certain number of times, enterprises will convert them into general-purpose parts through the standardization department to promote their application.

Standard parts: parts that have been selected, simplified, unified and given standard codes.

Special parts, borrowed parts, general parts and standard parts can be regarded as a classification attribute of all kinds of parts that make up the product structure of an enterprise. The computer should be able to automatically manage special parts, borrowed parts, general parts and standard parts according to certain rules.

Common rules to deal with are as follows:

1. Automatically identify whether it is a standard part according to the code name.

2. Judge that the component is a borrowed part according to the borrowing instructions marked on the parts list on the drawing. If the borrowed part already exists in the system, it should automatically link attributes, structure information and associated drawing files according to the code.

3. Once the special parts are borrowed by other products, it will be shown as a borrowing relationship on other products, which should be obviously different from the special parts. And when summarizing the "product list", we must indicate the source of the borrowed product. Because enterprises generally do not produce drawings for borrowed parts, if the design department is responsible for providing drawings, they should find the corresponding borrowed product drawings (usually bound into a complete volume or a cabinet) according to the product schedule (usually bound into a complete volume or a cabinet). Then according to the needs (mainly depends on whether there are corresponding drawings in the workshop) to decide to send out the drawings, if it is the workshop drawing, it is necessary to find the archival department to ask for the drawing according to the "product list".

4. In the case of manual management, the original borrowing relationship must be found for the borrowed parts, and then fill in the schedule manually, which is easy to make mistakes. It is often not clear which of the original borrowed products is borrowed. If the computer can automatically fill in the "borrow a product code" in the remarks column according to the product of the special parts corresponding to the borrowed parts, the errors and repetitive work can be greatly reduced.

5. In addition, an important judgment is that when there are multiple components with the same code in the system, first of all, they must be not standard parts, and only unique special parts must be guaranteed. Whether the general parts correspond to the special parts may need to be discussed.

6. Borrowed parts can be automatically converted into general-purpose parts if they are borrowed more than a certain number of times in different product series, and some enterprises have this management requirement.

7. General parts and standard parts can be managed in the basic parts library in 3.x, but it is not clear how to deal with the above problems in 4.0.

8. Need to be able to find out which products or structures a component is borrowed by. At present, the interface design of the final result of all query operations is very poor.

Replacement: the number of components that this product must have remains the same, such as the engine of a car. There are a variety of optional specifications.

Optional parts: this product does not have to have components, there can be multiple optional specifications.

Personally, I think it can be divided into:

Must be installed: must have, the structure remains the same

Required: there must be. Choose one by default.

Optional: it doesn't have to be there, choose one by default

Optional: it is not necessary, it is not selected by default

Customized parts: a new structure specially designed for this product

Required parts, required parts, optional parts and customized parts can be regarded as a kind of loading structure management attribute of all kinds of parts that make up the product structure of an enterprise. The computer should be able to automatically complete the configuration management of the product structure with this definition according to certain rules.

Self-made parts: the parts processed by the enterprise itself in the products of the enterprise and its components.

Purchased parts: the products or parts of other enterprises are purchased from our products and their components. Standard parts are generally treated as a special purchased part.

Outsourcing parts: the products or parts of other enterprises or branches are purchased in the products and components of the enterprise, but the enterprise is responsible for the drawings and process design.

Accessories: special tools and testing instruments necessary for users to install, adjust or use the product, or necessary for the product to complete a variety of functions, but can not be assembled on the product at the same time.

Attachment information often has a packing drawing with some packing details on it. For the packing list summary is also a very unscientific solution. From how to establish the product structure tree representation of the packing list, to how to expand the BOM, because the drawing should theoretically be associated with the product, but the product BOM expansion object is the product assembly drawing, how to summarize it at last? Because even if the packing details are expanded, they cannot be distinguished from ordinary components.

Fragile parts: parts that are easily damaged in the normal use of the product and must be replaced during the specified period.

Spare parts: in order to ensure the use and maintenance of products, provide users with spare vulnerable parts and other parts.

Summary information that is very important to the maintenance department, but should be distinguished by the designer's input identification information before the summary. Therefore, the relative maintenance operation is difficult, and the summary is not difficult.

Safety parts: parts that have a significant impact on product safety performance, such as brake pads.

Important: parts that have a key impact on product quality, cost, or processing cost.

Key parts: generally, after a relatively complex process, the parts that need to be tracked during the production preparation process are generally obtained by screening the parts with the "key process" logo after the design of the process.

Important parts and key parts are generally information related to the difficulty and importance of process processing. Computer recognition needs to give a certain difference in filling in the process card.

Weldment (joint): an assembly consisting of several simple parts welded or otherwise (riveted). However, it is possible that most of the parts are not drawn separately, and the drawings are shared with the assembly. if the assembly drawings can not fully express the part structure, the relevant drawings will come out. It is very likely that no drawing subordinate part code is provided.

Left and right parts: textile machinery industry term, refers to the operation of different stations, but mirror symmetrical and share drawings of two parts.

Series: a group of parts that form a series and share drawings. It is often possible to establish a dimension-driven table corresponding to a specific specification code. Only fill in the first half of the name and code in the title block.

The above weldments, left and right parts, series parts and some similar structures the biggest problem is how to deal with the deployment of BOM? Especially for series parts, it is very unreasonable to require users to draw each part separately. The second essence at this time is that a drawing is associated with multiple structures, especially the process, which may be a typical process associated with multiple structures, how to deal with it when summing up?

If the public process route may be included in the actual design process, but the process card design still needs to call the typical process redesign and so on. It is quite complex, and Kaimu is vague about the management of these structures on many projects.

Process assembly (middleware): a structure that needs to be temporarily installed together in the assembly process, which generally breaks the corresponding assembly relationship of the product structure.

In essence, it is the construction of PBOM, and there is no answer how to deal with it from the existing ideas. The answer is to study the development and summary design of assembly process card compilation rules.

If you solve the problem of summarizing PBOM from assembly procedures, the so-called PBOM will be very simple. The problem is that the best way to solve the problem is on CAPP, not on PDM.

two

What is BOM?

In order to use computer to assist enterprise production management, first of all, the computer can read the product composition and all the materials involved. In order to facilitate computer recognition, the product structure expressed by diagram must be transformed into a certain data format. This kind of file describing product structure in data format is the bill of materials, that is, BOM. It is a technical document that defines product structure, so it is also called product structure table or product structure tree. In some industrial areas, it may be called "recipe list", "factor table" or other names.

In MRP Ⅱ and ERP systems, the term material has a broad meaning. It is a general term for all products, semi-finished products, work-in-process, raw materials, spare parts, collaborative parts, consumables and other production-related materials.

In the usual MRP Ⅱ and ERP systems, BOM refers to the relationship tree composed of two parents and their children. BOM can be in the form of top-down decomposition or bottom-up tracking.

In MRP Ⅱ and ERP systems, BOM is an organizational relationship between data. Using the hierarchical relationship between these data can be used as the basis for the design of many functional modules, and some forms of these data are summary reports that we are all familiar with.

three

What is the purpose of BOM?

BOM is the most important basic data in PDM/MRP Ⅱ / ERP information system, and its organizational format design and rationality directly affect the processing performance of the system. Therefore, according to the actual use environment, it is very important to flexibly design reasonable and effective BOM.

BOM is not only an important input data in MRP Ⅱ system, but also an important basis for financial departments to calculate costs and manufacturing departments to organize production. Therefore, BOM has the greatest influence and the highest requirements for its accuracy. The correct use and maintenance of BOM is a very important work during the operation of the management system.

In addition, BOM is also an important interface between CIMS/MIS/MRP Ⅱ / ERP and CAD,CAPP and other subsystems, and it is the key point of system integration. Therefore, when using computer to realize BOM management, we should fully consider its information exchange with other subsystems.

BOM information is used for MRP calculation, cost calculation and inventory management in MRP Ⅱ / ERP system. BOM comes in various forms, depending on its purpose. The specific uses of BOM are:

1. It is the basic basis for computer to identify materials.

2. It is the basis for making plans.

3. It is the basis for matching and receiving materials.

4. Follow the machining process according to it.

5. It is the basis for purchasing and outsourcing.

6. Calculate the cost according to it.

7. It can be used as a reference for quotation.

8. Conduct material traceability.

9. Serialize, standardize and generalize the design.

four

What are the forms of BOM?

4.1 classified by use

The product has to go through three stages: engineering design, process manufacturing design and manufacturing, and the corresponding BOM EBOM, PBOM and CBOM with very similar names but different contents are produced in these three processes. These are the three main BOM concepts.

Project BOM--EBOM (Engineering BOM):

The data structure used in product engineering design management, which usually accurately describes the design index of the product and the design relationship between parts. The corresponding documents are mainly in the form of product schedule, drawing catalogue, material quota schedule, product classification schedule and so on.

Plan BOM--PBOM (Plan BOM):

EBOM is redesigned by process engineers according to the processing level and capacity of the factory. It is used in process planning and manufacturing management. using it, we can clearly understand the manufacturing relationship between parts and parts, and track how the parts are manufactured, where, by whom, with what and so on. At the same time, PBOM is also one of the key data structures of MRP Ⅱ / ERP production management.

In fact, BOM is a broad concept, according to different uses, there are many kinds of BOM; BOM on the design drawings, planning BOM, calculating the final product assembly manufacturing BOM, calculating the cost of BOM, maintenance BOM and so on. According to the different emphasis of application in different stages, we often see different BOM formulation, the common ones are:

Design BOM--DBOM (Design BOM):

The DBOM of the design department is the overall information of the product, corresponding to the common text format, including product list, drawing catalogue, material quota list and so on.

The source of design BOM information is generally the title bar and parts list information in a complete set of design drawings provided by the design department. Sometimes it also involves some information on the process cards prepared by the process department.

The design BOM is generally generated at the end of the design. If there are a large number of borrowing relationships in the design situation, we can basically summarize the design BOM at the beginning of the design phase, and then arrange the design tasks according to the newly generated parts.

The corresponding electronic view is often in the form of product structure tree, and each node on the tree is associated with all kinds of attributes or graphic information. It mainly appears as the basic data of product management and drawing and document management in PDM software.

Manufacturing BOM--MBOM (Manufacturing BOM):

The MBOM of the production department is perfected on the basis of EBOM and according to the requirements of manufacturing assembly, including the JBOM of machining parts and the PBOM of rough embryos, moulds and fixtures according to the process requirements. It can also be called process BOM. The corresponding common text format includes process route table, key process summary table, key parts list, self-made parts list, general parts list, general tooling list, equipment schedule and so on.

The source of manufacturing BOM information the general process department compiles the content on the process card, but the design BOM should be used as the basic data content.

The corresponding electronic view is often in the form of assembly process BOM for product parts, and it is often in the form of specific machining process BOM for parts, and most of them are machining process BOM, or production and processing flow route process BOM, etc., and each node on the tree is associated with process information such as tooling, equipment, man-hours, processing diagram and so on. The assembly process BOM is of great value to enterprises, which mainly appears as the basic data of production planning in ERP software.

Among them, in each process or step, it is necessary to specify the code, name and quantity of the parts in this process.

Customer BOM--CBOM (Customer BOM):

Customer BOM actually has two meanings, one is to filter out the catalogue of products ordered by customers from all product organizations. A list of products of specific specifications ordered by the user. This is mainly a very practical form of expression for some enterprises that manage and organize product drawings according to customers. This situation is more common in the PDM system, but in the ERP system, the situation is more complicated because it also takes into account the impact of different customer orders on the production plan, and may be extended to the scope of the planned BOM.

Sell BOM--SBOM (SALE BOM):

Sales BOM is the part of product structure that is configured according to user requirements. The corresponding common text format forms include basic parts schedule, general parts schedule, special parts schedule, option schedule, replacement schedule, change notice for special requirements, and so on.

The source of sales BOM information is generally a summary of the details of different types of parts of a series of products.

The corresponding electronic view is often in the form of product configuration tree, and each node on the tree is associated with all kinds of attributes or graphic information. It mainly appears as the basic data of product configuration management in PDM software.

Maintenance BOM--WBOM:

The maintenance service department is generated according to the maintenance requirements, and the corresponding text format includes the list of consumables, the list of spare parts, the list of vulnerable parts and so on. The source of maintenance BOM information is generally screened from the corresponding record attributes of the design BOM to obtain the details of consumables, spare parts and easy-to-wear parts.

Generally complete the summary in the PDM software, can also be used as the basic data in the ERP software.

Purchase BOM--CBOM:

It is produced by raw materials, standard parts and complete sets of components purchased according to production requirements, and the corresponding text format mainly includes purchased parts list, external parts list, self-made parts list and material list.

The source of purchasing BOM information generally comes from the summary of information on design drawings and process cards. The purchasing department or the production preparation department shall arrange the purchase plan and production plan according to it.

The PDM system can generally summarize the corresponding purchasing BOM information according to the drawings and process information, but if you want to obtain the dynamic purchasing BOM information for the product batch, it must be completed in the ERP system. For example, 100 batch procurement BOM and 10000 batch procurement BOM may vary greatly in outsourcing and outsourcing parts. The parts that may be purchased in batches are relatively low in cost, but they can be made by themselves when the batches are large.

Cost BOM--CBOM (Costing Bill Of Material):

Is produced by the MRP Ⅱ system. When the enterprise defines the management standard of standard cost, suggested cost and current cost of parts, the system automatically generates CBOM through the accumulation of PBOM and machining center. It is used for manufacturing cost control and cost variance analysis.

Among them, the closest integration relationship is EBOM controlled by PDM and MBOM in MRP Ⅱ.

4.2 divided according to design software

4.2.1 BOM in CAD

The design department is not only the designer of BOM but also the user of BOM. Single parts such as drawing number, material name (material type such as 45 steel), weight, volume, design modification audit number, material effective date, etc.; components or components also include external parts, purchased parts, general-purpose parts, standard parts, borrowed parts, assembly quantity of each single part, assembly drawing number and other information The master drawing (assembled from parts, components, etc.) also includes packaging, assembly list, technical documents, product instructions, warranty, and other information, which are part of BOM information. In the design department (CAD), the so-called BOM is actually a parts list, a technical document, focusing on the summary of product information.

The design department organizes BOM information according to the drawing number of a certain type of product. After receiving the order, according to the requirements of the order, the design department generally has three kinds of design ideas-top-down form design, bottom-up form design, and middle-to-end form design. No matter which kind of design method, the organization of the drawing number is consistent, all merge the product information according to the drawing number to form the general list of the product, the summary table of standard parts, the summary table of purchased parts, the summary table of outsourcing parts, etc., and can also generate the product drawing catalogue when needed (to meet the customers or outsourcing factories that do not run the ERP system). Sometimes a same part belongs to different products, so it has different drawing numbers, so it does not necessarily consider the uniqueness of enterprise material coding. It should be noted that after the formation of the bill of materials, each material has a unique code, that is, the material number. Do not confuse the parts list (CAD is commonly referred to as BOM) with the BOM information in ERP. The part detail information table in the design department is transformed into BOM information in the ERP system, which requires the cooperation of the design department, the process department and the production department, as well as the management of PDM (product data management) design product relationship characteristics to solve the similarities and differences between the part detail list and the BOM table, especially the inconsistency between the drawing number and the code number. (the PDM product structure module is completed through its rule base, variables and part list.

As far as use is concerned, whenever the product structure changes, or when the customer changes the technical document, involves quality problems, or re-improves the design of a part, in order to ensure the accuracy of the bill of materials, must be based on the design change notice. Under the guidance of the design change notification file, the design department obtains the information of all the parts and the structure information between them through the BOM information table. Only when this information is obtained can it be defined, described, or modified so that production can operate normally (especially the customer's emergency change notification). According to the design change notification number, with the support of PDM, you can easily retrieve change information and guide production activities such as production, shipping and after-sales service.

In the actual production process, design change is an important factor leading to inaccurate data, so there must be a set of effective design change notification management methods to manage design change notification. As it involves sales, procurement, production, engineering, finance and other departments, the senior supervisor of the enterprise generally manages the design change notice directly. This process has to go through five steps: design change notification confirmation, analysis, approval, documentation and supervision. Part of the data generated by the design department (CAD) is processed by PDM and transmitted to the ERP system.

There are several concepts that need to be added to the design of BOM:

The constituent elements of components in the product structure tree can be divided into three categories: standard components, structural components and design components.

The design parts can be generated from different 3D CAD or 2D CAD parts lists, which are designed by our factory or collaborative factory.

A structural component can be a photo or a simple sketch. The node names on the corresponding product structure tree are often product shape diagram, product dimension chain diagram, product assembly relationship diagram, packaging parts and so on. This information must be reflected on the product structure tree of many enterprises, but the information cannot be obtained from the final assembly drawing, for example, the product appearance drawing and the product assembly drawing are acceptable if they are hung on the product node. but users tend to think that product shape drawings and product assembly drawings are at the same level. In addition, like the packaging subtree, you need to manually establish the wrapper sub-node and expand it, which cannot be associated directly from the schedule through BOM expansion.

General parts include standard parts library and industry and enterprise common parts. And can be modified and deleted and merged, to join the general parts library to carefully verify the process. General-purpose parts can evolve from borrowed parts.

The structural components of the same product, and sometimes even design components or standard components, can have many different choices. Therefore, the same product in manufacturing and sales quotation can also have different product information structure combinations (such as price, batch, delivery date) for different customers. However, these situations are generally maintained in the ERP system, and the PDM system only needs to ensure the integrity and consistency of the basic data.

4.2.2 BOM in CAPP

After the product has been designed by the design department, part of the electronic data is transferred to the process department to formulate the process route (CAPP), which becomes a document explaining the processing or assembly process of the parts. It is not a technical document, but a planning document or a production guidance document. CAPP is generally composed of process card, machining sequence card, forging and casting heat treatment card, inspection card, tooling material working hours and other summary information; in a machining process card, it is composed of working procedure (processing steps), man-hour quota (occupying the load time of the work center), processing equipment, testing equipment, processing tools, fixtures, materials, etc.

In the preparation of the process plan, it not only involves every detail of the design, but also involves the main work center materials, processing fixture materials, tooling materials and auxiliary materials in BOM. Maintaining the accuracy of these static data is a prerequisite to ensure that production goes according to plan. The equipment maintenance, spare parts management, maintenance records, material purchase and inventory changes of the main work center, as well as changes in processing fixtures, tooling equipment and auxiliary materials should be reflected in the process planning in real time. In the process of process planning, it is necessary to browse BOM information at any time (object-oriented), input BOM information, alarm BOM information (process planners find error alarm), reflect updated BOM information in real time, and so on.

Without the support of the computer system, it is necessary to put forward high requirements for the process personnel: not only to be familiar with the current status of the parts processing process and processing equipment, but also to know the technical parameters, inventory, processing fixtures, tooling equipment and so on. In general, it takes 20 years for an enterprise to train a similar person. Now, with the support of computer system, craftsmen can easily query the typical process database designed according to BOM structure, obtain design information, query machine tool equipment and other technical parameters, and can also easily compile CAPP to ensure the integrity, consistency, correctness and feasibility of process documents. The data generated by the process department (CAPP) are processed by PDM and transmitted to the ERP system.

4.2.3 BOM in PDM

PDM is actually the core module connecting CAD/CAPP and ERP. It manages the "ERP" and "CAD/CAPP" technologies related to the product, and plays an important intermediate process from "CAD/CAPP" technology to "ERP" technology and from "ERP" to "CAD/CAPP" technology, forming a two-way seamless transmission of data and avoiding the generation of a large number of coincident data. The following figure shows their structural relationship.

As different departments have different forms of BOM information, enterprises often spend a lot of manpower and time to complete these reports, but also constantly maintain the consistency of BOM to avoid serious MRP operation errors. Sichuan Electrical Appliances Co., Ltd. used the original manual input method, input from the CAD department statistics of BOM information, a skilled input personnel to enter the BOM data of a product takes a week or so, does not include the rework time caused by input errors and caused a bad impact; now through PDM, automatic transmission of BOM data for the ERP system only takes a few minutes.

Throughout the product life cycle, PDM takes the data warehouse (all systems can share a database) as the underlying support, takes the bill of materials (BOM) as its organizational core, connects all the engineering data and documents that define the final product, and realizes the organization and management of product data. Such as product configuration management, drawing and document management, workflow management, design change management, rights (role) management, version management, project management, maintenance records and log management and so on.

According to their respective functional characteristics and different solutions to engineering problems, PDM systems are divided into three categories: those focusing on document and data management; those oriented to CAD based on design process and product structure management; and those oriented to hardware and software heterogeneous system integration platforms. Among them, the second kind is the most closely related to BOM information, and after transformation, it can achieve the BOM information needed by ERP. Today, most popular PDM systems can be integrated with ERP systems, and some ERP have their own PDM products, which effectively promote the communication and communication among production, design, procurement and sales departments in ERP system.

4.2.4 BOM in ERP

In addition to the system described above is related to BOM, the production department, the product cost accounting department, the material requirements planning (MRP) system and the sales department also have a great relationship. The production department uses BOM to determine the manufacturing method of the part or final product and determine the bill of materials to receive. The product cost accounting department uses the current cost of each self-made or purchased part in BOM to determine the cost of the final product and maintain the product cost, which is beneficial to the quotation and cost analysis of the company's business. BOM is one of the main input information of MRP in the material requirement planning (MRP) system. It uses BOM to determine the main production plan project, dynamically determine the net material demand, know which self-made parts and purchased parts are needed, how much and when, and analyze the difference between standard materials and actual materials. The sales department accesses the data source through Internet, which can easily quote prices, provide accurate parts design information and track the manufacturing process and other self-service, and customers can also place orders to purchase product spare parts.

Through BOM information, we can easily assess the performance of various departments and extract information for statistics and analysis. If there is a new demand for BOM data, we can also use the original BOM data to construct new BOM data to simplify the compilation of approximate BOM data. If we make an in-depth study of BOM information, we can also study the error checking of other product BOM data through different product BOM materials, so as to avoid errors caused by computer input or modification, and minimize the error rate.

BOM is the foundation of any management system, and it is related to almost all functional departments in the enterprise. If there is no BOM, the same product cannot be produced, which directly affects the processing performance and use effect of the system. For this reason, in order to improve the efficiency of the production management system, whether the BOM is correct or not is very important. Although the data has been very accurate, but do not ignore the importance of people, for special changes, the use of manual editing of the content of BOM information in the system to add, delete and modify, can successfully complete the task.

By establishing the two main lines of enterprise "ERP" management and "process (CAD/CAPP)" technology, with BOM as the information link, PDM as the core, combined with CAD/CAPP and ERP system, supplemented by Internet and EDI system, the goal of enterprise information construction can be truly achieved.

five

What summary tables are required for each stage?

What's it for? What format?

A complex product design process often consists of several major stages: "contract decision-making-overall design-work drawing design-process route assignment-process design-tooling design-summary of man-hours and material quotas".

5.1 after completing all the design work

According to the ISO9000 file requirements, there should be a "file directory" about the project

The project included in the document catalogue is all the design documents for formal production or trial production and random factory delivery.

Since there is no drawing and document management design related to the project in PDM, design documents (such as market forecast report, technical research report, pilot test outline, pilot test report, feasibility analysis report, feasibility assessment report, new product development project proposal, technical quotation, technical agreement, contract, technical assignment, etc.) cannot be managed and summarized at present.

5.2 after the completion of the product drawing design

After the completion of the drawing design, there are many summary requirements:

"drawing catalogue": generally compiled for products and working drawings of all products, the general summary fields include parts code, name, drawing code (generally the same as part code), drawing frame, number of sheets, base drawing total number, remarks. Can refer to the national standard format.

But there are two things that are special:

1) in some enterprises, there are multiple pages of assembly drawings for a product assembly or some parts, which we do not seem to be able to deal with.

2) in addition, the product may correspond to several drawings for different purposes, such as assembly drawings, general drawings, exterior drawings, installation drawings and diagrams, which may also be summarized in the drawing catalog, and may be summarized as a record in the parts list of the product. and it needs to be placed behind the product node.

"Product parts list": product parts are generated according to certain serial number rules. There may be some requirements on the pagination. The main summary fields are format, code, name and specification, material, quantity, unit weight, total weight, remarks (remarks generally need to fill in the outsourcing contract and which product to borrow). Can refer to the national standard format.

"Product graded parts list": the product only summarizes the parts details of the subordinate level, and then gives the subordinate level parts details for the subordinate level parts, and the entire product assembly structure can be expressed completely by multiple parts list together, which is similar to the effect after the parts structure file in PDM4 is opened. You can refer to Yuejin Automobile's "Product grading schedule" format.

"list of Series products": used to reflect the loading relationship of all the parts used in this series of products in different specifications, it is convenient to understand the borrowing relationship of parts among the whole product families. It is widely used in multi-variety, small batch or variant design enterprises, which is the difficulty of summary configuration at present, which has not been well solved. In the textile machinery industry, there are almost a large number of automotive industry.

Typical table 1 is as follows:

Hierarchical number

Code name

Name

Materials / specifications

Product 1

Product 2

Product 3

Product 4

Product 5

……

one

one

one

one

one

one

Product specifications are expandable

one

two

two

two

two

two

two

two

one

one

one

one

one

two

three

three

three

three

three

six

three

two

two

two

two

two

one

one

one

one

one

one

...

Express the application and quantity of each part in the product specification under the product specification. The table can better support Kanban management or material collection adjustment management in production management.

Many process cards, especially assembly process cards, are also designed in this way, which can succinctly express how the material receiving relationship of a series of assembly processes changes when different specifications are put into production. This kind of assembly process card is very many in Yuejin car, how to get the solution I have not seen the complete plan yet.

There are many ways to deal with sequence numbers, but there seems to be no good solution for summarization expressed in hierarchical numbers. Hierarchical number has two common expressions, the first is the number, the second is the number of decimal places, which is displayed as several decimal points.

Typical form 2 is as follows:

Hierarchical number

Code name

Name

Materials / specifications

……

Product 1

╳

Product specifications are expandable

Product 2

╳

Product 3

╳

Product 4

╳

Product 5

╳

...

╳

.

Part 1

one

one

one

one

one

.

Part 2-1

two

two

two

two

..

Part 2-2

two

..

Part 3

one

one

one

one

one

..

Part 4-1

three

three

three

three

...

Part 4-2

six

...

Part 5

two

two

two

two

two

.

Part 6

one

one

one

one

one

...

In fact, the first variant of this kind of table has exactly the same meaning, and it is common in Japanese drawings or textile machinery industry. However, when the product specifications are greatly increased, there are too many columns in these two expressions, and the printing processing is more complex. Therefore, many enterprises have developed a selective reading with card format based on EXCE L to read specified filtering rules and quantity of products to display and print. There are many small changes in the specific format, which are basically derived from these two changes.

The above two tables reflect the composition of the parts during the assembly of the variant machine, and the sequence of the assembly parts is also expressed if the assembly process card is embedded. This kind of summary schedule is difficult to compile and has many contents. When there are too many variant models, the designer or technician will put the assembly process of the model into the installation schedule, and those old models or models that are not produced now still occupy the space of the list, which leads to more and more contents of the list and more and more complex management, so if a better management method is put forward on this basis. At the same time, it is more important to keep intuitive summary and convenient variant design operation, which is also a big selling point of multi-variety and small batch management.

The items that need to be summarized in the design stage are "self-made parts list", "purchased parts list", "external parts list", "borrowed parts list", "drawing catalogue", "standard parts list", "packing list" and so on. A summary of detailed requirements and instructions have actually been described earlier.

In addition, there are two special summary management requirements for the product list, because many combination groups for variant models may borrow the combination groups of other models, and some joints, joints or parts are added or reduced on this basis, so the combination group list is usually compiled in the form of additions and reductions (relative to the structure of the standard configuration). And all levels of catalogs (a total of six levels) can be expressed in the form of additions and reductions. For the specific structure, please refer to the addition and subtraction of BOM below. Such requirements are common in the engine, compressor and diesel engine industries.

There is also a summary management requirement is not expressed in the form of additions or subtractions, but in the form of replacement, deletion, and new tables, which is essentially a comparison of the relationship between the two product structures.

Serial number

Standard product A

Number of standard loaded parts

Variant product Acord 1

Number of loaded parts for AAAGUP 1

A

A/1

1

B

1

2

1-1

D

1

Replace with D1

1

1-1-1

10

1

Delete

1-1-2

30

1

1

1-2

20

2

2

two

C

one

Increase the quantity by 1

two

2-1

thirty

two

two

2-2

forty

one

one

2-3

fifty

one

one

three

ten

Add 10

three

four

F

New F

one

five

G

New G

five

5.3 draw up the product process plan

-this work is no longer done in most enterprises, but there may be in the new product development process, but you can create a separate document workflow in PDM project management to manage it.

5.4 process route design, compilation of process route cards or workshop division schedules

-almost all large and medium-sized enterprises do not immediately begin to carry out process planning, but process route design after completing the drawing design. in fact, the most important meaning of process route design is that the route design completes the product processing task and the process planning task has been sent to the relevant branch factory or workshop to complete. This is called secondary process management. In the past, all the software avoided this link, and it is obviously problematic to take the route as a summary result.

1) the first requirement for process route editing is to be able to compile in batches, and enterprises often have their own habitual expression format when editing process routes. at present, there is a single process route editing, and the function of batch editing is already being developed. when designing the process route, the enterprise needs to add a lot of attributes to each part, such as material quota information, processing number information, all of which are completed when filling in the process route. The process route we are developing is supported in the scheme.

The question now is whether these attribute information can be automatically passed to CAPP. And after the CAPP information is completed, the final summary process route table can express the information completely and store it in a data table.

2) the expression of the process route table many enterprises have adopted the expression of "multi-column dynamically expandable workshop header + sequential digital route filling in the table", so does our summary form fully refer to the enterprise habit? The rationality of this expression is to facilitate the relevant factories below to find their own related parts and components. In the past, the process routes were managed manually. The following process departments at all levels should manually screen out all the parts and components related to their own processing from all the process routes, and then arrange the process planning tasks.

Only a few common formats are listed here:

Serial number

Name

Code name

Quantity

……

Process route

……

1 / blanking-2 / heat treatment-3 / metalworking-4 / final assembly

The above is an ideal way to fill in the form which is suitable for computer processing. Such as the form of 461.

Serial number

Name

Code name

Quantity

……

Process route

Preparation of materials

Carpenter

Cast iron

Heat treatment

……

All workshops generally belong to a large column, called process route.

The number of columns of the process route is generally fixed, and the expansion space is reserved.

The process route is generally filled in according to the order of production and transfer of parts in different workshops, if the first step is carpentry, write 1 in the woodworking column, the second step is heat treatment, then write 2 in the heat treatment column, the third step is cast iron, then write 3 in the cast iron column, and the fourth step is heat treatment, then write 2 stroke 4 in the heat treatment column, and so on.

As there are many general process routes, each column is very narrow. If a part enters a certain type of work for many times, it may mean that there is not enough space to fill in. Such as the form of CITIC heavy aircraft.

Serial number

Name

Code name

Quantity

……

Branch 1

Branch 2

Branch 3

Preparation of materials

Preparation of materials

Preparation of materials

Metalworking

Heat treatment

...

Welding

Final assembly

...

This kind of table actually refines the process route according to the branch factory or workshop. It is essentially the same as the second type.

Then, in the case of computer management, it is bound to automatically split out all the parts related to the employees of the branch factory. if it is provided in the computer that the processing workshop automatically filters and displays all the parts related to an enterprise according to the process route (not necessarily in the form of structure tree, that is, in the form of parts list), and then automatically assign tasks to these parts in batches. It can guide the enterprise to give up the expression form in the past and adopt the expression way which is easier to realize.

3) the process route must be audited before it can be effective, issued, and the batch task function can be provided according to it, so the process route editor (which may be compiled by multiple people at the same time) does not have the function of the next task. Instead, the process route can be issued only after it has been reviewed by the chief craftsman. And the audit of the process route can not be an one-by-one review, it must be a product review. How to realize the batch audit of the process route also needs to be tested after the function is developed.

1. Process design

-prepare all kinds of process cards according to the processing requirements of the process route. The process division is completed by PDM, and the process content editing is completed by KMCAPP. After editing, the process file information is automatically stored in the database.

1) process planning tasks can be automatically assigned and relevant process documents can be created according to the process route, and then process planning tasks can be assigned by those with certain permissions, but in the case of non-automatic assignment, how to significantly distinguish between parts objects that have been assigned tasks and those that have not been assigned tasks, and which process planning objects have been assigned and how can they be significantly identified? Can the borrowed parts with process procedures be reasonably hidden?

2) due to the large number of parts and components of the product, it is obvious that there is an overall assignment in the process planning task assignment process, which is assigned to a certain technician or process group to complete.

3) for large-scale products, there are obviously a variety of management needs for process diagrams, and inserting process diagrams may not meet the needs. Can you imagine the effect of inserting a No. 0 drawing on the process card?

Process control program

-preparation of process cards corresponding to process cards, there may be no such process. Done in KMCAPP.

Process design of unit process

-prepare operation instructions or self-test instruction cards. Generally, we compile them in the process cards. Done in KMCAPP.

Compilation of tooling schedule and task book of tooling design

First of all, it is necessary to be able to determine which special tools are special tools when filling in the process card and process card, generally through strict control of the code. But the problem is that if no off-the-shelf tooling is found from process Explorer or other means, coding support may be required to fill in the tooling code. According to the special tooling used for the first time, it is necessary to issue the task book of tooling design, how to automatically assign the tooling design task according to the first-used special tooling batch? Tooling in KMCAPP as a box to fill in the content, how to easily become an object for management? Or do you need to set up tooling objects by hand and assign tasks by hand?

Formulate process material quota and process man-hour quota

-after the completion of the process design, the process man-hour quota is filled in by the man-hour quota personnel. at this time, the man-hour quota and process preparation can be regarded as a follow-up workflow for the compilation of process cards, or it may be for the tasks under the process planning objects. this task is man-hour editing.

The summary and statistics of material quota is not only a specialized knowledge, but also a product that enterprises are willing to pay a high price, but Kaimu has never made a good summary in this respect. I can't sum it up completely for the time being. So let it go. However, it is suggested that a detailed study of Jianghan oil plant, Xinjiang special changes, Nanjing Mint (its own development program), 461 and other functional requirements, can get a more complete impression.

Special tooling design

At this time, it is mainly drawing design, and its flow control is no different from the general parts drawing design. After the drawing design, it has to go through a process and tooling verification stage to prove the rationality of the tooling.

six

What are the forms of product structure tree?

In order to facilitate computer management and processing, the product structure tree must have some reasonable organization form, and in order to facilitate the use of the product structure tree in different situations, the product structure tree should have a variety of organization forms and formats. The previous chapter mainly expresses a variety of summary reports in enterprise language, these reports can actually be expressed in a unified BOM model in the computer, all kinds of BOM prototypes mentioned in this section should be able to find corresponding prototypes in the previous chapter.

After the data of the product structure is input into the computer, it can be queried and displayed according to the different formats of each user. The goal of various information system systems is to enable the input data to generate product structure trees in different formats to meet the needs of various users in the enterprise. The product structure tree generally follows the following commonly used output formats.

Figure 1 shows the product structure of A. 0 layer for the product Atera is made up of BBQ 10. C is made up of the first layer, B is made up of 20Perry D, C is made up of 30Magi 40Perry 50, 20Perry D 30Perry 40Perry 50 is made up of the second layer, D is made up of 10Perry 30 units, and 10Perry 30 constitutes the third layer. In the figure, the letters represent the assembly, the numbers represent the parts, and the numbers in parentheses represent the quantity required for the assembly.

For products like A, the BOM output formats are as follows.

6.1Common BOM forms

6.1.1 single-stage deployment BOM

The single-level expansion format displays the subordinate components used by an assembly. The multi-level structure of the product can be represented completely by using multiple single-stage expansion. The grouping schedule corresponding to many enterprises (especially those with a large number of product parts) is the specific form of single-level BOM. The following table shows a list of four single-level deployments for the given four-level product structure.

BOM in the form of monolayer expansion of A, B, C and D

Assembling parts

Spare parts

Quantity required for each assembly

A

B

one

C

one

ten

three

B

D

two

twenty

one

C

thirty

two

forty

one

fifty

one

D

ten

one

thirty

one

6.1.2 Multi-level deployment BOM

Multi-level expansion BOM shows all subordinate components used by an assembly. The multi-level structure of the product can be represented completely by using a multi-level expansion. The product list corresponding to many enterprises (especially those with a small number of product parts) is the specific form of multi-level BOM. The following table shows the given four-level product structure corresponding to the multi-level expansion BOM table.

BOM in the form of monolayer expansion of A, B, C and D

Serial number

Spare parts

Belong to the parts

Number of assemblies required

A

one

B

A

one

1-1

D

B

one

1-1-1

ten

D

one

1-1-2

thirty

D

one

1-2

twenty

B

two

two

C

A

one

2-1

thirty

C

two

2-2

forty

C

one

2-3

fifty

C

one

three

ten

A

three

6.1.3 indent and expand

The indented line expansion format is to list their subordinate materials in the form of indented lines under each upper layer. All part numbers at the same level are displayed on the same column. The format of line expansion is to represent the product in the way of product manufacturing.

Layers

Part number 1pm 2pm 3

Quantity required for each assembly

one

A

two

B

one

three

. twenty

one

three

. D

two

four

. . ten

one

four

. . thirty

one

two

C

one

three

. thirty

two

three

. forty

one

three

. fifty

one

two

ten

three

6.1.4 Summary deployment

The summary expanded format lists the total quantity of all the materials that make up the final product. It reflects the total number of parts required for a final product. Instead of the number of parts required for each upper layer. If a part is used for multiple assemblies, a summary and expansion of the list will help to determine the appropriate purchase quantity. This format does not represent the way the product is produced, but it is conducive to product cost accounting, procurement and other related activities.

Assembling parts

Parts

Quantity required

A

ten

five

twenty

one

thirty

four

forty

one

fifty

one

(B)

(1)

(C)

(1)

(D)

(2)

6.1.5 single layer tracking

The single-layer tracking format shows the upper material that uses a material directly. This is a list of where a material is used, and it indicates the upper layers of a material that are used directly. The multi-tier structure of product A can be shown in the following table:

Part number

Upper layer material

Quantity required for assembly

ten

A

three

D

one

twenty

B

one

thirty

C

two

D

one

forty

C

one

fifty

C

one

6.1.6 indented tracking

The format of indented tracking indicates the use of a part in all high-level materials. It can find all the high-level materials that use a part directly or indirectly, and it is valuable to use this format. The following table shows:

Part number

Upper layer material

Quantity

thirty

D

one

. B

two

. . A

one

C

two

. A

one

6.1.7 Summary tracking

The summary tracking format shows all high-level materials containing each part and the number of parts used for each material. This is an expanded "where to use" list, which lists all high-level materials that contain parts. "required quantity" represents the total number of parts required to assemble materials at that level. See the following table:

Part number

Upper layer material

Required quantity

D

A

two

B

two

ten

A

five

B

two

D

one

thirty

A

four

C

two

D

one

twenty

A

one

B

one

forty

A

one

C

one

fifty

A

one

C

one

6.1.8 Matrix BOM

Matrix BOM is a kind of BOM obtained by data merging of product series with a large number of general parts. This form of BOM can be used to identify and assemble common parts in a product family. In the following output format, various common parts are listed on the left, each final product is listed on the upper right, and the number below indicates the number of parts required to assemble a final product. "#" means that the product does not use this part. This form of BOM is useful for products with many general-purpose parts. However, matrix BOM does not specify the way of product manufacturing, and it does not indicate the assembly level between parts, so it can not be used to guide the manufacturing process of multi-layer structure products.

See the following table:

Part number

Product model

A X Z

ten

5 5 2

twenty

1 2 #

thirty

4 7 2

forty

1 1 #

fifty

1 1 #

sixty

# # 3

(B)

1) (2) (1)

(C)

(1) (#)

(D)

(2) (1) (2)

6.1.9 add and subtract BOM

This kind of BOM is sometimes referred to as "comparative" or "similarities and differences" BOM. It is based on standard products and specifies which parts can be added or removed. A specific product is described as a standard product plus or minus some parts. The following table shows that the special product Aamp 1 is made by adding parts F and G to standard product A, while increasing the number of part C to 2, and removing parts 1-1-1. This method can effectively describe the differences between different products, but it can not be used for market forecast, nor is it suitable for MRP.

Serial number

Standard product A

Number of standard loaded parts

Variant product Acord 1

Number of loaded parts for AAAGUP 1

A

A/1

one

B

one

one

1-1

D

one

one

1-1-1

ten

one

-1

1-1-2

thirty

one

one

1-2

twenty

two

two

two

C

one

+ 1

two

2-1

thirty

two

two

2-2

forty

one

one

2-3

fifty

one

one

three

10

3

3

four

F

+ 1

one

five

G

+ 5

five

6.1.10 Modular BOM

In practical application, because the product specifications are changeable, the parts list can be divided into the following categories according to the characteristics of the product structure:

The product is single and the specification is basically unchanged.

A variety of product specifications, you can choose to assemble

Products are serialized, but the performance changes in the same series.

Different product lines, a variety of selective assembly.

Modular BOM is used for complex products made of many general-purpose parts and with multiple combinations. For example, in the automobile industry, assembling a car can choose different engines, transmission, body, parts, decoration and other things, and different choices can be combined into different final products. The modular method not only provides customers with a wide range of choices, but also reduces the inventory of parts. This method has been widely used in industries such as automobile and agricultural equipment. When there are many optional features on a production line, many combinations can be obtained, and it is impossible to predict them separately in the master production plan. If you store a separate BOM for each final product in your computer as required by MRP. Then the storage and maintenance of document records will be very expensive. The solution to this problem is to use modular BOM. Modular BOM builds modules according to the requirements of assembling the final product. The process of modularization is to decompose the product into low-level modules. Forecasting according to these modules is more accurate than directly predicting the final product. Modularization can achieve two different purposes:

You can get rid of the trouble of combining optional product features.

Distinguish general-purpose parts from special parts.

6.2Integration of BOM

In many enterprises, rebuilding the traditional BOM can greatly simplify the master production plan. If the delivery time of the order is less than the production lead time of the product, the demand should be predicted in the main production plan. Most enterprises organize production in two ways, one is stock production, they plan according to forecast; the other kind of enterprise organizes production according to user order in a short time, and arranges plan according to forecast in the rest of the time. Therefore, the product must be defined in a form that can be predicted in the production plan. Obviously, in the order production environment, the final product is not the best predictor. Some special BOM is needed to associate the master production plan with related parts that must be obtained before a customer order is received. The BOM for planning performs this function, which reduces the number of projects in the forecast and master production plan.

According to the needs of MRP, the plan of BOM is to disassociate the products of layer 0 from BOM and raise the components of layer 1 or lower to the status of the final project. In this way, a new modular BOM for planning is established, which can meet the needs of forecasting, master production planning and material requirements planning.

The manufactured BOM lists the optional features necessary to make the final product. It is only a BOM that aggregates independent modules to meet the customer's selected products or warehouse orders. This kind of BOM generally does not directly belong to the MRP system, but defines the required materials through the general assembly schedule and combines with the MRP system, as long as these materials use the parts planned and provided by the MRP system.

6.3 use of BOM

In any manufacturing environment, different departments and systems use BOM for different purposes (the following BOM belongs to different categories and is expressed uniformly as BOM), and each department and system obtains specific data from BOM. The main BOM users are:

Design department

The design department is not only the designer of BOM but also the user of BOM. As far as use is concerned, whenever the product structure changes or a part is redesigned, the department has to obtain the information of all parts and the structure information between them from BOM. Only by getting these information can they be defined, described or modified.

Process department

The process department establishes the manufacturing process of each part and the assembly process of the assembly according to the BOM information. And determine the tooling, moulds and so on that should be used in the manufacturing process.

Production department

The production department uses BOM to determine the manufacturing method of the part or final product and to determine the bill of materials to receive.

Product cost accounting department

The department uses the current cost of each custom or purchased part in the BOM to determine the cost of the final product.

Material requirements Planning (MRP) system

BOM is one of the main input information of MRP. It uses BOM to determine which self-made parts and purchased parts are needed, how much and when they are needed in the main production planning project.

6.4.The construction of BOM

As mentioned earlier, BOM is the most important basic database in the system, and it is related to almost all functional departments in the enterprise. The quality of BOM construction directly affects the processing performance and use effect of the system. Therefore, according to the actual environment, it is critical to construct BOM flexibly. In general, you should pay attention to the following aspects when constructing a BOM.

1. In BOM, each project (part) must have a unique code. For the same project, no matter which product it appears in, it must have the same code. For similar projects, different encodings must be used no matter how small the differences are.

2. For the convenience of management, sometimes the different states of the same part can be regarded as several different items and constructed in the BOM of the product.

3. Parts in BOM, the hierarchical relationship of parts must reflect the actual assembly process. In actual assembly, sometimes some parts are not necessarily assembled into some named components, or some parts need to be processed together because of technological considerations (such as boxes and lids). Temporary components are formed, but these components are not reflected in the parts list and assembly drawings of the product, but must be reflected in the plan management, so it is necessary to set up a project in BOM that does not physically exist, usually called "virtual sheet" or "virtual part", whose purpose is to simplify the programming process of MRP and reduce the influence between parts.

4. According to the actual production situation, sometimes in order to strengthen the preparation of certain tools and moulds, these tools can also be constructed in BOM. In this way, some important production preparations can be included in the plan. Sometimes in order to control some important links in the machining process of an important part, such as quality inspection, different machining states of the same part can be regarded as different parts and constructed in BOM.

5. In order to meet the different information of parts obtained by different departments, the attributes of each project in BOM can be designed flexibly. For example, planning, cost, inventory, orders.

6.5 Common problems in the conversion from design BOM to manufacturing BOM

1. The parent-child relationship of parts in the design BOM may be different from that in the manufacturing BOM. For example, an assembly code 5401000 in the automobile industry belongs to 5010000 in the design BOM, but belongs to the soldering and receiving module in the manufacturing BOM structure, which belongs to the same level as 5010000. In other words, the father-son relationship in the design BOM may become the brotherly relationship in the manufacturing BOM.

2. The part drawing number of the parts in the design BOM needs to be divided into multiple codes (for example, code + workshop code) in the manufacturing BOM, which can be used to pick up materials in different workshops. That is to say, a part in the design BOM may have several corresponding codes in the manufacturing BOM with the change of the production route, and there is a parent-child relationship between the codes according to the flow order of the production route. Generally, the corresponding code in the final completed workshop is the parent node of the corresponding code in the superior workshop.

3. The code of some parts on the design BOM may remain the same, but because in the actual assembly or machining process, it needs to be divided into several parts belonging to different parts (these parts may be generated by the second case) for different workshop materials, corresponding to the need to split into several child nodes (each node associated with a different number of materials) corresponding to different parent nodes.

4. Because the borrowing phenomenon is quite common, for the borrowing of the whole parts (different kinds of parts), in order to meet the needs of the change processing of the manufacturing BOM, the structure is established in the form of adding and decreasing parts in the manufacturing BOM, and the number of parts is negative. There is no negative number in the design BOM.

5. When the part drawing number in the design BOM is converted to the manufacturing BOM, the workshop code (prefix) should be added to indicate the processing workshop (in and out of the warehouse).

6. The parts in the design BOM often have only the product code, and they often need to be converted into the material code in the manufacturing BOM, so there is a problem of conversion from the product code to the material code. And it is likely that product codes and material codes or other industry codes coexist.

6.6Design the conversion scheme from BOM to manufacturing BOM

Conversion of material code:

Use the drawing number (in the material number) as a bridge between the two BOM systems. That is, when the product code of PDM is the same as the drawing number of the material code in MRP, they are considered to be the same material.

When PDM extracts information from MRP, it uses the drawing number as the identification (code) in PDM, and if the drawing number already exists in PDM, it is considered that the product already exists in PDM. If there is a difference in other attribute information between the two, it can be submitted to the user to decide which system to use.

The product added in PDM can be added to the material information, that is, its item number is generated according to the coding rules in MRP. If the product comes out of the design project process, add it to the material information when the project is completed.

The flag can not only save the information in the data conversion process, but also speed up the system query and conversion product speed, and can add a field to the material information table and product property table. it is used to identify the status of the product transition, the existence of the drawing number and other information. The next conversion can be based on this field to determine whether it needs to be processed. The logo can do the following functions:

The meaning of the logo:

In PDM: this product is from MRP

The product comes from MRP, and its structure or attribute information has changed in PDM.

The product has been transferred to MRP, but has changed in PDM.

The product is generated in PDM and not transferred to MRP. (default)

The product is generated in PDM and transferred to MRP.

In MRP: this product is from PDM

The product is generated in MRP and transferred to PDM.

The product is generated in MRP and not transferred to PDM. (default)

The product has been transferred to PDM, but has changed in MRP.

Convert from PDM data to MRP material data:

At this time, look for the same number in MRP as in PDM. If it exists, it is considered that the product already exists in MRP, and marks it in two systems respectively. Otherwise, it is considered that the product in PDM is a new product in MRP, then according to the naming specification of MRP, the corresponding material number, name, weight, drawing number, specification and other information are added to MRP, and marked that it comes from PDM.

When the product (material) attribute and structure information are changed, the corresponding flag bits need to be changed in order to deal with correctly during the conversion.

Convert PDM data from MRP material data:

At this time, contrary to the above steps, that is, if the material drawing number in MRP has such a code in PDM, it is considered to exist. Otherwise, insert the drawing number into the PDM as a code in PDM. If the material does not have a drawing number, the material number can be inserted as a code in PDM, and the logo indicates that it comes from MRP.

The MRP drawing number is the same as the PDM code, but other attributes are different:

There are two ways:

²specifies that the data of one of the systems is correct and that the data of the other system can be overwritten during conversion. Since most of the data in PDM are extracted from drawings, we think that we should take the data of PDM as the standard.

When ²discovers this situation, it gives a specific prompt, and it is up to the user to choose whether to overwrite it or not, thus giving the decision to the user.

The above two methods can be made into options for easy use.

Transformation of product structure:

As mentioned earlier, the product structure of the two systems is inconsistent. The transformation of the product structure should be carried out synchronously during the above conversion process. When converting a product or material, we must first recursively extract all its sub-product or material information, judge whether it has been converted according to its logo, and if not, deal with it according to the above method. Otherwise, you can skip it. However, the structure must be transformed according to the corresponding structural information. The specific algorithm is not studied here.

Information input of virtual parts or process assemblies and machining accessories on manufacturing BOM

Generally, according to the assembly process card, the information of virtual parts and auxiliary materials used by the system in the whole process can be summarized. PDM can provide operation to establish a complete manufacturing tree in MRP system before the product structure tree is transformed into the manufacturing tree in PDM system. PDM can provide two kinds of nodes which are different from product nodes, which can be called virtual nodes and material nodes. According to the assembly process relationship, the node information can first establish a complete manufacturing BOM in the PDM system according to a certain operation, and then export these manufacturing BOM trees to the MRP system and carry out coding conversion at the same time. However, when the virtual node information and auxiliary material information are summarized in the PDM system, they are not included in the product parts list and product drawing parts list.

Process route and process information

In MRP, process route information and process information correspond to a certain material. It shows that a material can also get process information in CAPP or BOM in PDM, and this information can be converted from PDM to MRP data at the same time.

6.7maintenance of BOM

BOM is the foundation of any management system. If there is no BOM, the same product cannot be produced. Therefore, in order to improve the efficiency of the production management system, it is very important whether BOM is correct or not.

6.7.1 incorrect BOM impact

Some items were omitted by BOM, resulting in a shortage of parts.

Some unnecessary items are included in BOM, resulting in an excessive stock of parts.

Due to the excessive number of missing parts, the manufacturing efficiency is low.

The order cannot be delivered on time.

The quality is low.

The plan lacks credibility.

Incorrect product cost.

Abandoned inventory.

6.7.2 the link where an error occurred in BOM

When the engineering department produces BOM

When preparing data for BOM

When entering BOM data

6.7.3 ways to maintain BOM correctly

Assign a special person to maintain the BOM

Regularly monitor BOM to check the number of projects and their effective dates

Classify BOM data changes

²critical change-done immediately. For example, the product can not achieve its function, or is not conducive to safety.

²urgent change-- completed quickly. For example, the engineering department sets a reasonable date to complete the change.

²routine changes-only when changes are required from an economic and practical point of view.

²temporary change-temporarily change the field data without changing the BOM data.

²implementation of software changes-make a good data import conversion plan and coding reorganization plan, focus on one-time batch import. To complete the main product data maintenance of the leading series.

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