Exploration and Application of Vehicle Harness VAVE Method

This paper mainly analyzes the purpose and method of VAVE from the perspective of product research and development in automotive wiring harness industry, and introduces the mining method and execution process of VAVE through specific examples and experience of VAVE process steps, hoping to give some thoughts and references to colleagues who have not done VAVE specifically, so as to understand the significance and role of VAVE in cost control.

As one of the most important and complex parts of automotive wire harness automobile, the wiring loom products are finally made from various materials through dozens of different processing technologies. In this process, how to effectively control the cost has always been the research topic and direction of the harness enterprises. According to the complete cycle of wiring harness products tracked by the automobile industry, in the process of design, procurement, manufacturing, packaging and logistics, effectively organizing the mining and application of VAVE scheme can reduce the total cost by 10%~30%. Even from the perspective of R&D design alone, the total cost can be reduced by 5%~15% according to the statistics of past successful cases. This paper will focus on the analysis of VAVE mining methods and applications in the R&D and design stage.

I. Overview

VAVE, the abbreviation of ValueAnalysis and ValueEngineering, usually refers to value analysis and value engineering. Their differences and applications are briefly quoted as follows.

Value analysis is the stage of mass production of products. On the premise of not reducing the quality, function and performance of products, the design structure, processing method and manufacturing process are continuously analyzed and improved. Value engineering is a value and cost innovation activity around realizing the necessary functions of products at the lowest life cycle cost in the product development and design stage.

According to the working procedure of VAVE, it can be divided into three steps: ① put forward the VAVE scheme; ② evaluate VAVE scheme; ③ Implement and popularize VAVE scheme. Among them, effectively mining and putting forward the VAVE scheme is equivalent to completing one third of the work, so it is extremely important to provide the scheme.

Second, the three stages of VAVE and the timing of its presentation

1) The initial design stage of the project. For the developed vehicle with design authority, the wire harness design belongs to the front-end design developed synchronously with OEM, and the wire harness supplier will be present to participate in the principle, 2D and 3D design of the wire harness. 3D engineers can see the assembly environment, 2D engineers are responsible for database establishment and component selection, and principle engineers are responsible for wiring harness topology diagram and circuit schematic diagram. This stage is the best stage for proposing VAVE and designing VAVE, and suggestions can be made according to their respective responsibilities.  

2) Small batch trial installation stage (verification stage) of the project. Every project will have a small batch trial installation process. This stage is the verification of all aspects of the project, and VAVE schemes can be considered from many aspects.

3) SOP stage of the project (mass production). SOP is the mass production stage of a project, which starts to load cars in large quantities. This stage also tests the capabilities of the project, and it is also the last stage to identify VAVE.

III. Steps and methods of VAVE

According to the current VAVE experience of wire harness industry, most wire harness industry enterprises have five common methods to carry out VAVE: ① Material cost analysis; ② Internal manufacturing and process cost analysis; ③ Disassembly and comparison of competing wire harnesses; ④ customer demand analysis; ⑤ Product supply chain analysis.

3.1 Material cost analysis

Whenever you get the P-ReleaseBOM of a new project, you can make a preliminary analysis by screening the material types and the proportion of suppliers, and make a statistical graph according to the proportion of new and old materials (inherited materials and newly added materials). You can probably see the VAVE space of this project on the materials, and then conduct targeted research on each type of materials, get the proportion of various cost structures, and find the modules and types with higher cost. This can be used for equivalent substitution analysis, including considering VAVE scheme from price, service, technical route, etc., with the aim of optimizing product design, cutting and merging the number of parts, and saving the cost of parts and materials. The BOM in SOP stage can be analyzed by the same VAVE method, and some room for cost reduction can also be excavated.

3.2 Internal manufacturing and process cost analysis

During internal manufacturing and process cost analysis, we should first consider the application of new technologies, new processes and methods that have been verified. This requires technical exchanges between the design department and the process manufacturing department, and some optimized design schemes can better reflect the advantages of cost reduction in technology. For example, a battery terminal scheme, which changed from crimping to welding chip terminal, deleted the insulation crimping structure, reduced the material quality, improved the material utilization rate and cost price, and at the same time had better sealing performance.

3.3 Disassembly and comparison of competing wire harnesses

If the price of wire harness products is obviously higher than that of competing products, it is necessary to disassemble the competing wire harness by analyzing the wire harness structure, material selection, process method, etc. of competitors. Through the most intuitive comparison and analysis, on the premise of meeting customer standards, we can see how competitors can effectively control costs. This process is a very good process of learning and summing up, gathering the strengths of many people, organizing and reviewing the optimization scheme of their own products.

3.4 Customer demand analysis

As OEM OEMs have different attitudes and strategies towards VAVE, some OEMs are proactive, so we have to respond to the initiative of OEMs and actively promote VAVE. Some OEMs may not realize the importance of VAVE, or have strict requirements for quality, so they are reluctant to carry out VAVE easily. At this time, we should make use of our professional knowledge to actively promote VAVE and introduce the cost advantages that VAVE can bring. In short, carrying out VAVE activities is a valuable work that is beneficial to both suppliers and OEMs' cost reduction.

3.5 Supply Chain Analysis

From the internal point of view of wire harness enterprise, supply chain is a circular process of the enterprise itself from the purchase of raw materials to the delivery of finished wire harnesses to customers. As tier1, the general wiring harness factory's external supply chain should also include upstream tier2 parts suppliers and downstream OEM OEMs.

When carrying out VAVE cost analysis of supply chain, we should think more about dimensional cost control, which requires all functional departments related to the total cost of wiring harness enterprises to participate. First of all, each department applies VAVE analysis method, puts forward the scheme and reviews it internally, and then the project or technology leads the organization of the general review, giving the final cost optimization scheme. At the same time, the purchasing department is responsible for negotiating the active participation and cooperation of external chain parts suppliers, and the final plan will be reported to the OEM for approval and implementation, so as to achieve a win-win situation for all parties.

Fourth, the specific methods and examples of VAVE.

4.1 from the perspective of new technology and process methods

For example, the application of copper-aluminum wire hybrid welding technology, which is suitable for the solution of long and large square battery wires, can be considered according to the layout trend and space of the wiring harness in the 3D layout stage. For example, there is enough space to accommodate the wire diameter of aluminum wires, and aluminum wires can be designed and applied in this layout space. For example, the area where the hole-type terminals at both ends are connected to the electrical terminals is limited, and the copper wire scheme can be adopted, so that the mixed utilization of two kinds of wires can perfectly solve the problem of uneven space, and it is also for the consideration of lightening the wiring harness and reducing the cost.

4.2 Whether there is excessive design?

Take the heat-shrinkable tube as an example. When selecting the type, analyze whether the heat-shrinkable tube is over-designed in the following aspects: Is the length, diameter, temperature resistance and shrinkage ratio of the heat-shrinkable tube over-designed? Are there any sealing requirements? Is there an excessive brand premium?

4.3 Cost Composition Analysis of High Voltage Harness

The cost of high-voltage wire harness consists of material cost, processing cost, packaging and transportation cost and management cost. As a special kind of wire harness, the material cost is mainly determined by the technical scheme of wire harness, among which the cost of high-voltage wire harness is the heaviest compared with that of low-voltage material. The material cost of high-voltage wire harness accounts for about 73.8% of the total wire harness cost. It is necessary to optimize the design and production process, and the most effective VAVE scheme is to reduce the cost of high-voltage wiring harness by reducing the material cost.

4.4VAVE Checklist and Thinking Analysis

Every wire harness material (wire, sheath, terminal, buckle, bracket, pipe, adhesive tape, waterproof seal, accessories) has the possibility of VAVE in theory, whether it has been defined by the customer or has the opportunity to choose its own type. Engineers need to use their own professional knowledge to analyze and dig deep into VAVE schemes.

Material VAVE inspection items such as: whether the material has price difference caused by the difference of origin; Capacity risk and delivery risk; Whether it has been over-designed; Compare the prices of multiple suppliers; Whether the types can be reduced or merged; Whether the cost can be reduced by optimizing design or process manufacturing methods, etc.

V promotion and tracking of VAVE scheme

1) the customer offered (reasons: ① pressure from cost; ② Prepare for cost optimization).

2) The supplier of spare parts offered (reasons; ① Realize localization; ②Tier1 year reduction requirement).

3) After analysis by the wiring harness engineer, it is put forward (reason: ① there is VAVE space; ②Tier2 supply capacity).

4) After the conclusion of the contract, the wiring harness engineer should connect the preceding with the following and do a good job of communication, promotion and tracking progress among the three parties.

VI. Verification and Implementation of VAVE

Tier1, Tier2 and customers, no matter who put forward the VAVE scheme, must go through a rigorous verification process, which can actually prove that the substitutability of the substitute parts is complete. It is necessary to provide the feasibility of the scheme through supporting documents, experimental verification and mature cases that have been verified, and finally implement it for the purpose of meeting the requirements and interests of the three parties.

VII. VAVE implementation process

Verified VAVE schemes need to be approved by formal documents from different customers. The final OEM customers can directly release ECR for engineering change approval. For some schemes that still need process verification, they can first approve Deviation for implementation, and then release ECR instead of implementation after full verification.

VIII. VAVE Tracking List and Results Statistics

VAVE is a tedious and even long process, so the progress and problems of every VAVE scheme should be tracked and recorded. Tracking table is also an important tool to do a good job of VAVE, and the ultimate goal of tracking is to track every scheme to "implemented".

Statistical list of VAVE results: ① Comparative information of part numbers before and after the change; ② Comparative information of quotation before and after the change; ③ Cost saved for your company before and after the change; ④ Cost savings for customers before and after the change. Of course, it is also possible to add more detailed statistical items.

The significance of doing VAVE statistics: ① as the basis for viewing and reporting VAVE value; ② The embodiment of self-accomplishment.

IX. Summary

VAVE is a collaborative work of teams and a new management technology. It is an effective method to reduce costs and improve economic benefits through directional and organized program research and analysis through collective wisdom. It is reasonable to use this method to make the lowest cost price of products in a limited life cycle. Under the premise of not reducing product quality, and based on scientific and systematic experimental verification, VAVE reflects the value of cost control methods. As one of the important tools of cost management, VAVE cost management method has been attached importance by more and more companies, and will be widely promoted and applied to various industries.