Analysis of influencing factors of BOM accuracy
Before analyzing the influencing factors of BOM accuracy, the first question to be solved is what is “inaccurate BOM”? In the product life cycle, BOM is a dynamic data, which is always changing. For a product, BOM inaccuracy can be summarized in two aspects: one is the inaccurate definition of the product, and the other is the effective time. Not allowed.
Inaccurate product definitions, from a configuration perspective, may be configuration definition errors, such as mutual exclusion of single product configurations, inconsistent upstream and downstream configuration definitions, and so on. From the perspective of the part, it may be part information error, part basic attribute, digital model drawing number, version, special identification and other errors.
From the perspective of BOM, there may be errors in the number of parts constituting the BOM, BOM structure, part usage, and delivery methods, or it may be that the BOM of a product with different management forms is managed separately and cannot be associated and matched. The direct manifestation of these errors is a certain product Configuration definition does not have an accurate BOM data to match it in each application field.
The effective time is inaccurate, mainly because the product definition or design change adopts the inaccurate time in the BOM of different management forms, such as the time of the breakpoint on the BOM does not match the actual execution time. These BOM errors will cause big problems in business areas such as process manufacturing, material control, cost accounting, and after-sales maintenance.
In addition, regardless of the BOM management mode, whether the BOM data is centralized or decentralized, how many types of BOM data are in the business chain, and whether there is BOM system management or offline management, BOM accuracy is first of all a business issue.
Therefore, to analyze the factors that affect the accuracy of BOM, this article only starts from a business perspective, and the influencing factors of all aspects are generally classified into two categories, BOM architecture and BOM management methods, to start the analysis.
① Unreasonable BOM architecture design
First, the heterogeneous management of different BOM management forms is likely to cause a series of problems such as heavy BOM management workload and low BOM management efficiency. These problems will affect the accuracy of BOM in daily BOM management .
The most common is the heterogeneous management between EBOM and MBOM. This management method occupies a large proportion of domestic manufacturing enterprises. The most fundamental reason for this problem lies in the CAD design structure and the homogeneous management of EBOM, and most of them are EBOM leans toward CAD design structure.
The advantages and disadvantages of this management method will not be repeated in this article. However, as far as BOM management is concerned, the structure of EBOM will inevitably not meet the coordination requirements of various business areas (including cost, procurement, manufacturing, after-sales, etc.).
In the super BOM organization mode, the complexity of BOM reconstruction is much greater than that of accurate BOM. If BOM management is a one-time data construction job, this complexity is nothing.
However, for the manufacturing industry, especially domestic automobile manufacturers, the maturity of product development management of a considerable proportion of the enterprises is not high. After the design project is released, a large number of engineering changes will still occur throughout the entire product life cycle. In this business context, heterogeneous management of different BOM management forms will bring huge difficulties to the assurance of BOM accuracy.
Second, the BOM accuracy problem caused by the mismatch between the BOM management unit setting and the business maturity.
Super BOM is a BOM management mode that must be adopted after the product configuration is enriched. It is a matter of course as the business management level gradually improves. Domestic car companies started late, the platform-based development model is not mature enough, and modular development is in the groping stage. Therefore, the division of product spectrum lacks reasonable technical support, which brings certainty to the determination of BOM management unit Troubled.
Some companies’ BOM management units are designed to be too large and do not have a matching management level to support them, leading to confusion in the management of super BOM data and low accuracy. Some companies’ BOM management units are designed to be too small. This situation is common in companies that adopt a strong project management product development model. The degree of platformization is low and the number of products is large. As a result, the number of BOMs is very large.
It is a very time-consuming task to ensure that the impact of the change on all related products can be considered and verified when changes occur. If the management is not in place, the reuse of models will become smaller and smaller, and the problems will not be caused. It’s just that the accuracy of the BOM is low, and the cost of the vehicle will continue to rise, which directly affects the benefits of the enterprise.
Finally, the BOM management form and application form are unclear, and the main line of BOM management is not clear, which can easily lead to confusion in the BOM management of the entire business chain.
The direct manifestation is that a product has its own BOM data in different business fields, and each BOM data is managed independently, which leads to the fragmentation of the BOM data of the entire business chain and the extremely poor flow of BOM data.
For example, once some companies generate BOM application requirements, they prepare a BOM for management, resulting in a product with CAD_BOM, early BOM, EBOM, procurement BOM, trial production BOM, process BOM, manufacturing BOM, order BOM, after-sales service BOM, KD_BOM, cost BOM There are a lot of BOM forms such as weight BOM and so on. There is no effective data synchronization mechanism between BOM forms, and the accuracy of BOM data cannot be guaranteed.
These problems are mainly due to the lack of an overall BOM design for the entire business chain, and the role and form of the BOM have not been clarified. Therefore, in the overall design of the BOM, we must follow the Dfx-oriented BOM management ideas. First, we should distinguish the main management form BOM such as EBOM, MBOM, SBOM, and the application form BOM such as purchase BOM, cost BOM, weight BOM, etc. Data relationship between BOM.
The role of BOM should not be narrowly limited to satisfying individual business applications. For example, EBOM data cannot be managed only from the perspective of product design thinking, but should be positioned as a data bridge for product development synchronization engineering, which bears product design The key information of the synchronization project must also support the actual needs of each business within the scope of the synchronization project and the key information carrying, and finally release for manufacturing, after-sales and other businesses.
② The management method is unreasonable.
First, the lack of BOM business management processes and specifications will cause confusion in the entire business chain of the BOM, let alone the accuracy of the BOM.
On the whole, the input and output of BOM business of each management form are not clear, the application object of BOM is not fixed, the initialization and release time of BOM are free and arbitrary, the processing of BOM changes at different stages is unreasonable, and the necessary BOM management verification specifications are lacking. Rigorous BOM problem feedback handling mechanism, etc., will cause BOM data errors.
If this chaotic administration is not reversed, no matter how excellent design and product development capabilities are, it will not be most effectively transformed into lean manufacturing due to management problems. From the perspective of each business point, the principle of part number replacement does not consider downstream execution requirements, non-standard part configuration conditions, unclear control methods and controlled scope of part information or BOM information, etc., will lead to low BOM accuracy.
Second, the unreasonable division of BOM management responsibilities will also affect the quality of BOM management.
The BOM data is decentralized management and there is no overall supervision mechanism as a guarantee. In this case, it is difficult to implement BOM management specifications, and the lack of unified data integrity monitoring can easily lead to poor coordination of BOM data among various professional systems, overlapping data or missing data. In addition, with the decentralized management of BOM data, it is difficult to formulate effective KPI management indicators to monitor the work quality of BOM managers.
If the division of BOM management responsibilities is unreasonable, it will lead to low communication efficiency and affect the accuracy of BOM. Taking the after-sales field as an example, SBOM is used as the data source for after-sales development. The best practice in the industry is to set up an after-sales engineering department in the R&D field to manage SBOM, after-sales atlas and other related after-sales services, and to work well with the design department in the development process Carry out synchronous engineering, and determine the after-sales repairability and after-sales maintenance strategy with the design department during the development process, such as after-sales splitting, etc., and take into account the needs of after-sales spare parts in the process of early determination.
However, if SBOM’s management responsibilities are set in the sales department, industry practice has proved that in companies with immature process systems or insufficient execution, this management method will only cause poor communication between after-sales and R&D, and data gaps between SBOM and EBOM. There are a series of problems such as difficulty in the procurement of spare parts, and difficulty in executing after-sales engineering changes.
Product configuration management and BOM management are independent, and the two lines are managed in parallel, which cannot effectively coordinate data. Especially in the super BOM management mode, this management method is fatal to the quality of BOM data.
The product type spectrum and configuration are all defined for the vehicle-level product, which directly determines the organizational form of the BOM, while the BOM data defines the development and realization of the product configuration. If the two data do not match, the super BOM cannot be accurately obtained. The definition of the BOM of the model has an impact on the business activities in the entire product development, manufacturing, and after-sales fields, especially for business activities that rely on accurate BOM such as engineering verification, process design and verification, manufacturing, MRP, material distribution And recoil, cost accounting, etc., have a huge impact, and even directly lead to the failure of individual downstream businesses.
Finally, poor change management will result in low BOM accuracy. The lack of a rigorous change management and control mechanism leads to a disconnect between change management and BOM changes.
In the early stage of new product development, some companies have insufficient research on market demand and low development quality. After the project is released, there will still be a large number of configuration adjustments and engineering changes that affect product quality. At the same time, a large number of factors such as cost reduction will also occur. Engineering changes, multi-point supplier development, etc.
For such frequent engineering changes, if the coordination between the process control and the BOM change management is not in place, that is, the two lines of change and BOM management, the BOM change lacks effective monitoring, and the accuracy of the BOM data depends entirely on the designer or The BOM engineer’s work consciously ensures that it is inevitable that the BOM accuracy rate is low under this management method. Inadequate implementation of changes will result in a decrease in the accuracy of the BOM of the entire business chain.
The respective business characteristics of R&D, manufacturing and after-sales will inevitably bring about inevitable management differences in product definition and effectiveness control between EBOM, MBOM and SBOM, such as the difference between production effectiveness and engineering effectiveness between MBOM and EBOM Differences, the difference between the after-sales accessory definition and the engineering definition between SBOM and EBOM, the difference between the after-sales validity and the engineering validity between SBOM and EBOM, the difference between the after-sales validity and the manufacturing validity between SBOM and MBOM.
Based on this, if the management of the change execution side is not in place after the engineering change is generated, the three BOM data of EBOM, MBOM, and SBOM will gradually be out of line and the consistency will be poor.
Temporary changes are initiated at will and are not managed in a closed loop, which will cause the difference between MBOM and EBOM to become larger and larger. Temporary changes must be time-sensitive, and should be avoided as much as possible in normal production operations. The scope of use of temporary changes should be clearly defined, and the implementation of temporary changes should be the most stringent.
However, the temporary changes of some companies cover a very large range. All business scenarios except formal engineering changes can be based on temporary changes to solve problems, such as temporary replacement of materials on the production side, emergency changes before formal changes, quality Concession release, part deviation permission, temporary replacement of process, etc., are all controlled by temporary change process.
From the point of view of management design, this method is not infeasible, but in the management and execution link, this kind of panacea design will artificially create many management loopholes as the execution inertia continues to accumulate.
The most serious situation is the continuous use of temporary changes to replace the emergency change process of the project, and the formal changes that should have been initiated have not been initiated or the management and control are not in place after the initiation, the result of the time is the confusion of product data and BOM data, who I also don’t know what the correct product design should be, and it’s even difficult to find out what condition parts should be used for repair after sale.
Therefore, the management of temporary changes must first determine the scope of application, and secondly, closed-loop management. The closed loop includes not only the switchback of temporary replacement of materials, but also the initiation and execution of the above formal changes. Of course, from the best practice in the industry, emergency engineering changes should also follow the engineering change process, which can speed up certain circulation links depending on the business situation , Instead of using a temporary change process to improve approval and execution efficiency.
In addition, there are also some human factors that lead to low BOM accuracy, such as parts design changes that do not follow the principle of changing numbers, data maintenance errors, errors in data flow, etc., which will affect the accuracy of BOM. This requires that in addition to strengthening professional training of business personnel, companies should also establish a complete and effective change management, data maintenance and release inspection and review mechanism, and formulate reasonable KPI indicators based on the current business situation to ensure that BOM data is in the entire business. The accuracy of the chain is maintained at a reasonable level.
The above is a simple summary and analysis of factors affecting the accuracy of BOM that are common in domestic manufacturing companies from two dimensions and multiple aspects. For some common problems, I hope to bring you some reference when diagnosing BOM problems.
Some factors themselves are not the necessary and sufficient conditions and direct causes that lead to poor BOM accuracy, but in a specific business context, such management will bring about the problem of poor BOM accuracy, such as heterogeneous management of BOM in different management forms, and so on.
The results of the above analysis may not be applicable to all companies. The BOM accuracy problems faced by different companies need to be analyzed in specific situations. The same management method may bring about completely different management effects under different business backgrounds. , So you cannot ignore the business background and apply directly.
Conclusion
Only by discovering the problem and accurately identifying the root cause of the problem can we formulate a corresponding solution to the problem.
The BOM business management model has its own characteristics in every enterprise. The background of the problem is complicated, and the division of responsibilities is not the same. To effectively solve the BOM problem, it is necessary to carry out in-depth business research and sort out the pain points in detail. , Starting from the whole business chain, carry out the overall design, and after repeated verifications, can we provide targeted solutions.
In a nutshell, when analyzing and diagnosing BOM problems, we must take care of the small issues and pay attention to small problems; when formulating BOM solutions, we must take care of the overall design and not only focus on one point and achieve the symptoms first. Only by curing the root cause can the problem be truly solved.
