Automotive wiring harness cost control and analysis
Blog | Sep 30,2022
An automobile wiring harness is the main body of the automobile circuit network, the purpose is to connect various electrical appliances. It acts like blood vessels in the body, acting as a channel for electrical signals.
Automotive wiring harnesses are mainly composed of wires, connectors, terminals, clips, tapes, and other auxiliary materials. The competitive pressure in the modern automobile market is great.
In order to achieve a win-win effect, wiring harnesses manufacturers need to ensure that their products meet customer quality requirements and achieve higher benefits with lower costs. To control the cost of automotive wiring harnesses, first of all, it is necessary to improve the qualification and accuracy of parts cost analysis.
A series of analyses and research is carried out on the parts cost of automotive wiring harnesses, and a variety of different analysis methods are used to select the appropriate control method for the cost of automotive wiring harnesses.
About the design of wiring harness products
The service object of the wire harness is the load source, which refers to the wire and connecting terminal assembled together with other parts, is the carrier of power transmission and speed up the transmission signal, and is the communication link in various fields of the automobile.
Automobile wiring harnesses can be divided into full utilization harnesses, partial utilization harnesses, and link systems according to the different structures. According to the different service modes, it can be divided into loss harness and waiting harness; According to the number of attached sources of the service, it can be divided into infinite load source harness and finite load source harness.
In addition to these, there is a classification, is divided into a main harness and small harness, this statement is according to the number of parts to distinguish, among them, the main harness contains engine harness, floor harness, instrument panel harness, the small harness includes roof harness, reversing radar harness, door harness, etc.
Alleged wire harness, it is to bind a variety of wire with insulating material into a bundle, the wire of different color, different specification is combined into an organic whole, more complete and unified, convenient its safety.
60% of the actual load of the wire and 60% to 100% of the actual load of the wire are suitable for two types of electrical equipment with long and short working hours, respectively. The cross-sectional area of the selected wire is selected according to the load current size of the automotive electrical equipment.
To make it easier to identify the wires in each harness, a different color and a letter representing that color are used. Wiring harnesses are generally assembled by plastic parts, terminals, wires, line protectors, rubber parts, brackets, fixers, and other attachments (including tape and sleeves) according to certain technological steps.
If the proportion of the raw material cost of wire harness is used to make Plato, then the three kinds of material costs of wire, plastic parts, and terminals are the largest part of the proportion. The raw material of wire harnesses is mainly purchased parts. The main method to control the raw material cost is to optimize the raw material cost of wire, plastic parts, and terminals through the method of calibration and VAVE.
Wiring harness product material function and technology production automotive wiring harness each place wire requirements are strict, but also out of the ordinary. Mostly from its electrical performance, temperature resistance and material sporadic and other aspects
such as engine wiring harness wire must use high temperature, oil resistance, vibration resistance, friction resistance;
The wire on the automatic transmission is resistant to high temperature, hydraulic oil, good stability;
The wiring harness on the suitcase cover must be selected to maintain its inherent elasticity in a low-temperature environment.
Therefore, the cold elastic wire should be selected to ensure its normal work. ABS wiring harness needs high-temperature conditions, generally choose 150-200℃ high-temperature environment, hard insulation layer, wear resistance, but to choose more than 133 stranded wire.
The functions of automotive wiring harness products can be divided into two kinds, one is the power line that carries the power of the drive actuator, and the other is the signal line that transmits the input command of the sensor. A thick wire with the function of carrying a large current is a power line, and a thin wire without the function of carrying electricity is a signal line.
With the change in social needs and the change in science and technology, the function of automobile modules is increasing constantly. Electronic technology has been widely used in modern new cars. The electronic control system is closely related to the automobile wiring harness.
As mentioned at the beginning of this article, a wiring harness acts like blood vessels in the human body and is an essential element. There is such an analogy: the car’s ECU and other control modules are equivalent to the car’s brain, the car’s sensors are equivalent to sensory neurons, executive components are equivalent to motor organs, and wiring bundles are nerves and blood vessels.
At the same time as the combination of technology and vehicle multi-function, many contradictions and problems have also arisen, such as how to effectively and reasonably arrange the car wiring harness in the limited space, so as to maximize the role and function of the car.
The process of production of automobile wire harnesses can be divided into four steps:
- first, the wire opening and crimping process
- second, the pre-assembly process,
- third, the assembly process.
- last, the final assembly process
The opening process needs to be serious and rigorous, its accuracy affects the whole production schedule, and the production efficiency will be affected if there is a little mistake.
So at present most wiring harness factories use fully automated wiring equipment; The crimping process needs to determine the crimping parameters and the crimping die required according to the customer’s crimping standard and terminal type.
Since the crimping quality is directly related to the electrical performance, this station is the key station, and it is required to have the crimping operation manual indicating the special characteristics and requirements, and the crimping quality formation characteristic control chart is randomly checked online according to the specified process in proportion.
As for the pre-assembly process, the primary task is to make KIT of the open wire crimped wire access plastic parts according to the process instructions, which will help reduce the investment cost of the assembly line equipment, reduce the difficulty of assembly operation, and reduce the number of assembly operators.
Simple car wiring harnesses can be directly canceled after preassembly, and for complex cars, wiring harnesses generally have to be set up preassembly station; After that, it is the final assembly process.
According to the procedure instructions, the preassembled wiring harnesses are arranged on the assembly tooling board in an orderly manner, and the wiring harnesses are arranged, the tape is wound, the cardine is bound, and the rubber parts and other accessories are installed. The last is the late process of final assembly, which includes the installation of brackets, live detection, full-size detection, and binding packaging.
The cost of automotive wiring harnesses is mainly material cost and production cost. The calculation method and benchmarking method are used to analyze and explore the composition of the cost of automotive wiring harnesses, so as to obtain the cost calculation method of automotive wiring harnesses, and to improve the accuracy of the cost analysis of automotive wiring harnesses.
Calculation method in a clear understanding of the automobile wiring harness product composition and production process under the premise, through the automobile wiring harness product parts and product structure calculation analysis, as well as the cost of each component calculation analysis method can be calculated and analyzed all kinds of cost factors.
The current cost of an automotive wiring harness includes three parts: raw material cost, manufacturing cost, and other costs.
Material cost According to the design requirements of the wiring harness, the product engineer will design the wiring harness product drawings and determine the wiring harness BOM from the perspectives of material selection/direction/performance.
The material cost of each wire harness in this project can be determined through the wire harness bill of the material provided by the product design department and the unit price of purchased parts confirmed by the purchasing department, according to the wire harness model ratio provided by the sales department and the model annual production forecast. Product design decisions in this process will directly affect the raw material cost of the wiring harness.
Through the analysis of the production process, the manufacturing process of automotive wire harnesses mainly includes the wire opening process, crimping process, pre-assembly process, final assembly, and inspection.
The cost of wire harnesses is closely related to the planning of the process production steps. For example, whether the pre-assembly work needs to be set up, whether the ultrasonic station is placed in the final assembly or pre-assembly, and the placement position of the material box will directly affect the production cost of the wire harness.
The wiring harness process design is related to the input of equipment, the input of personnel, and the planning of the site. The whole process design is centered on one goal, that is, how to improve the production efficiency and improve the utilization of existing equipment, site, and personnel as much as possible
Other costs include administrative costs, various development support costs, and additional transportation costs. When budgeting at the beginning of a project, raw material cost plus manufacturing cost multiplied by the corresponding coefficient are generally used as estimates.
Other costs = (raw material cost + manufacturing cost) * coefficient sum up the three main costs calculated to get the cost of the wire harness. Compared with the benchmarking method, the results of the calculation method are relatively accurate, but the time required is longer.
Benchmarking method in the product quotation stage many parts information is not complete, in this case, it is necessary to determine the approximate parts price information by benchmarking.
Find similar base point parts by benchmarking, and analyze the cost and price of wiring harness step by step by comparing the differences.
The calibration method is based on the details of the information mastered, the degree of accuracy is different, and the accuracy of the cost price marked also has a certain degree of difference, but its advantage is that the prediction speed is fast.
With the development of the era of big data, with further database analysis as the background, making data models will greatly improve the readiness of price prediction.
Internal developments in the automotive industry today focus on how to improve the competitiveness of new product development capabilities while reducing costs.
In the development process of new automobile products, it is of great significance to establish the design concept of economy as the center, reduce the purchase cost of new products after launch, and maximize the profit of new models.
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