Practice and exploration of BOM management of the

Practice and exploration of complex product batch BOM management

in manufacturing enterprises, BOM runs through the process of product conceptual design, detailed design, process planning, prototype trial production, processing and manufacturing, sales and maintenance until the product dies. With the advancement of enterprise information construction, BOM has become the core of enterprise product data management and the basis and bridge for data integration between application information systems. Many manufacturing enterprises only manage the product design and process bom effectively in the information construction, but the management of complex product structure relationships, especially complex product batch BOM, does not achieve the expected effect. The design of complex products such as locomotives and power generation equipment is complex, the number of parts and components of products is large, generally about 20000, up to 30000, and the maximum level of product structure can reach 20 levels. The relationship management of product structure of complex products is the key and difficult point of PLM system implementation. The degree of software system support and management directly affects the quality of enterprise information construction. Combined with the implementation practice and experience of PLM system in locomotive industry and power generation equipment industry in recent two years, this paper analyzes the establishment of complex product data model and the construction process and method of complex product batch BOM, and puts forward a solution to the management of complex product batch BOM in manufacturing enterprises, which provides a feasible management idea for enterprises to better manage product batch BOM

1. Analysis of product BOM management in manufacturing enterprises

1.1 current situation of product BOM management in manufacturing enterprises

according to the previous management mode, PDM manages product design BOM from the perspective of product design, and ERP manages product manufacturing BOM, planning BOM and cost BOM from the perspective of product manufacturing. For manufacturing enterprises with simple products, the product design BOM and process bom are basically the same. The product BOM is maintained by the product R & D personnel, and the process personnel make a small amount of adjustments to the product BOM from the perspective of enterprise processing and supplement the product manufacturing information; Some enterprises even build product BOM directly according to the characteristics and requirements of enterprise production and assembly in the process of product design. This management mode is relatively simple and saves management costs. Some manufacturing enterprises adopt the design mode of manufacturability and assembly. In the product design stage, product designers and manufacturing engineers negotiate and discuss, and use this kind of team work to avoid various production and assembly problems caused by the traditional design process of "I design, you make", as well as the increase of additional costs and the delay of final product delivery

1.2 problem analysis of product BOM management

after receiving market orders, manufacturing enterprises process and manufacture according to batches, and complete the technical preparation of each batch of BOMs before manufacturing. For manufacturing enterprises with complex product structure, especially those with heavy product R & D and production tasks, it is necessary to build all batch BOMs of the same order within the same time period, and effectively trace each batch BOM and the design and manufacturing data related to the batch BOM. In addition, in actual production, the structure of batch BOM will be adjusted due to design errors, technical improvements, changes in technical data, process adjustments and process route changes. Therefore, manufacturing enterprises have high requirements for BOM management of complex products, and face the following problems that need to be solved from the perspective of management

1) different batch BOMs reference the same parts, so it is necessary to solve how to build all batch BOMs of the same order in the same time period, and solve the problem of cross reference and change of different batch BOMs to the same part

2) design BOM and batch BOM use the same part, and different versions of the same part are used in different product views. It is necessary to accurately trace the version of parts taken in different batches

3) because in the actual process, the hardness range of design BOM, design drawings and batch Bo foaming finished products can be 5C (6) 0cm, and cross changes will be made. It is necessary to consider how to ensure the effectiveness of batch BOM after cross changes of BOM in different views

4) for the released batch BOM, how to record the accurate BOM of the units in the batch and trace it when the production changes

2. The necessity of product batch BOM management

manufacturing enterprises will form different processing batches of the same type of products in the production process due to different personalized needs of users, and each batch will process and produce multiple or more than dozens of units. According to the market contracts and orders, some of them need to re start the machine to carry the advantages of strong, that is, new product design, and some of them are deformation design or configuration design based on previous products. Production is organized according to orders. An order corresponds to a basic model product, and there will be different processing batches of the same product in the production process. The actual technical parameters of processing and production of these processing batches deviate from the product design requirements. This situation may be caused by the customer's special requirements for this batch of products, or by the enterprise's processing environment, resulting in the inconsistency between the product structure and design structure of this batch of production. It is necessary to readjust the product structure based on the product design BOM, form the batch BOM of this order product, and then build the manufacturing BOM of the product according to the batch BOM. For enterprises with a high degree of product serialization, it is also necessary to build a global design BOM according to certain configuration rules, and an instantiated batch BOM can be quickly formed according to the global BOM. Therefore, for manufacturing enterprises with complex products, it is very important to manage the product batch BOM well, so as to provide correct and effective product manufacturing data for ERP production planning

3. BOM management methods and building principles for complex product batches

3.1 BOM management methods for complex products

for enterprises with many types of products, complex products and high degree of product serialization, there are many product deformation designs. After designers create a standard BOM for a certain type of product, the serialization product design mainly carries out deformation design or configuration design on the basis of standard EBOM. If the enterprise has not implemented the ERP system, it is recommended to manage the product EBOM and pbom in PLM. After the designer carries out deformation design or configuration design on the basis of the standard BOM and obtains the instantiated EBOM, the process or manufacturing personnel maintain the process and manufacturing information on the basis of the instantiated accurate EBOM, directly build the batch manufacturing BOM, and output the batch manufacturing BOM information through the report function for processing and production. If the enterprise has implemented the ERP system, and the ERP system can receive batch information, or BOM with status and version information, it is recommended that the enterprise transfer the focus of BOM management to the PLM system, maintain all BOM information (EBOM, pbom and MBOM) in PLM, maintain the actual processing and assembly sequence of products and parts processing and manufacturing process information in PLM, take the PLM platform as the BOM management center, and PLM will transfer the maintained batch manufacturing BOM to ERP, ERP will no longer adjust the batch manufacturing BOM. After receiving the batch manufacturing BOM data, ERP will guide production and arrange production planning and scheduling

3.2 BOM management model of complex products

product data model is the basis for managing product structure and building complex virtual product model. With the virtual product model, we can effectively manage all kinds of information and the dynamic relationship between them in the whole life cycle of the product. At each stage of the product development process, an integrated product data model can finally be built, and a BOM management center can be established based on PLM to realize the integrated management of product design BOM, process bom and manufacturing BOM. The product data model can be established from the following aspects:

1) establish the resource database of basic materials such as enterprise standard parts, external components, raw materials and blanks, and establish the hierarchical structure and attribute information database of enterprise level basic parts, so that resources can be called to combine various products at any time during product structure design

2) establish a product data association model, with parts as the core and product structure as the main line, establish the association between product parts and model base, drawing files, etc., and realize the unified management of product design BOM, process bom and manufacturing. If the microcomputer has strong functions, it can directly print BOM

3) establish product configuration variables and configuration rules, combine product module division and interface definition with product configuration variable rules, and realize the configuration management of modular products

4) according to the characteristics of the enterprise, establish a product multi view data model, and establish the spread relationship between views through the effectiveness of time, version and status

3.3 principles to be followed in building batch BOMs

different processing batches will be formed in the production process, and batch BOMs need to be built according to the characteristics of enterprise products. From the perspective of management, the evolution of BOM in different views can be controlled through time validity, version validity, status validity, configuration validity and product baseline (snapshot). The following figure shows the evolution process of design BOM and process bom and the construction process of batch BOM. If the part version upgrade management mode is adopted for the construction of different batches of BOMs, the effective version distribution of different batches should be carried out strictly according to the time node. For example, after the first batch platform basic BOM is built, the effective version distribution should be carried out (the integrity of data should be guaranteed before finalization), and then the platform basic BOM should be built. The following principles should be followed in the construction of batch BOMs. After the design BOMs of products are built according to the requirements of customer contracts and orders, a design BOM can correspond to one or more batch process BOMs, and the process BOMs of each batch correspond to the corresponding manufacturing BOMs. The batch process BOMs and the corresponding manufacturing BOMs can also be combined into one BOM, and the batch manufacturing BOMs can be directly built according to the product design BOMs. In different batch BOMs, batch BOMs may use the same part, which can be managed by version upgrading or processed by changing the number. The number changing processing method can solve the problem of building multiple batch BOMs in the same time period, and the reference of the same part in batch BOMs, and can effectively trace the corresponding batch BOMs according to the batch

schematic diagram of the evolution process of design BOM and process bom and the construction process of batch BOM

3.4 how BOM changes affect batch BOMs

the change process is a process with a life cycle. The key of product data management is to effectively manage the change process, trace the impact scope of the change, and efficiently realize the change management. In the process of change, BOM changes will also be involved. Changes generally come from changes made by the product design department and changes caused by feedback from the processing site. Design changes may cause process changes and batch BOM changes. When the design is changed, the analysis and evaluation of the corresponding change must be carried out to determine whether the change of drawings or technical requirements has an impact on the product design BOM and batch BOM. It is necessary to follow the relevant change review process, issue the corresponding change notice, and timely notify the units affected by the change. When the drawing change involves non structural changes (such as adding technical state description, defect correction, performance improvement, etc.), and the latest version can replace the old version, the drawing does not need to change the number. At this time, it can be considered that all parts and components refer to the latest version of the drawing. When drawing changes involve structural changes (changes in key dimensions, major structural adjustments, and complete changes in configuration status) and are no longer applicable to other products, the designed parts and drawings should be numbered. In addition, PLM provides version management, status management, and data distribution and reception status management work areas