Wiring harnesses are mainly composed of wires, terminals, connectors, wrapping materials, clips, and wire slot brackets. The irregular composition of components means that wiring harness manufacturing is a relatively low level of automation and labor-intensive industry. The many manual operations affect the standardization of wiring harnesses, making the failure in the manufacturing process a random and uncontrollable failure mode. The most common failure modes in the manufacturing process need to ensure the quality of the wiring harness in each link of the process. Mechanically setting reasonable specifications and parameters for equipment, establishing standardized operations and comparison panels for manual operations, and finally inspecting the wiring harness in all directions to ensure the manufacturing quality of the wiring harness.
The arrangement of the wiring harness wires on the actual vehicle is broken down into multiple parts based on the vehicle assembly process, which increases their assembly and maintenance capabilities. However, the increase in the number of wiring harness interfaces and positioning components means that the probability of failure increases. This section summarizes the failure cases of the entire vehicle in the assembly process, in order to improve the reliability of wiring harness assembly. Wiring harness assembly continues from the overall assembly interior workstations to final assembly workstations, with a large span and many contact areas. Combining its failure mode and performance, it can be roughly divided into the following categories:
Fixation failure refers to the positioning components of the wiring harness itself falling off in the fixed holes or cable ties. This type of failure does not affect functionality, nor does it affect the use of the entire vehicle.
Functional failure is a more serious type of failure mode that can cause the loss of a certain function of the entire vehicle, and severely affect the driving safety of the driver.
Appearance failure is a form of failure that affects customer perception. Wiring harnesses are mostly arranged in areas that are not easily noticeable by customers. However, due to factors such as the supplier's process or space, parts attached to them may be affected, resulting in matching or aesthetic problems.
Such problems should be considered during the early design stage to determine whether there is any interference risk in the motion envelope area of the wiring harness or connector with the surrounding components, so as to choose suitable fixing points to ensure that the aesthetics are improved while meeting the functional requirements.
Durability failure is a type of failure mode that occurs randomly during the vehicle's lifecycle and is unpredictable. Once it fails, it will cause customers to complain greatly about the brand. Such failures mainly occur when wiring harnesses are in the motion envelope area of moving components and occur after a certain amount of wear, making them difficult to detect early on. Therefore, it is necessary to strictly control the arrangement of wiring harnesses in the motion envelope area while following strict evaluation standards for wiring harness wear.