Reliability of Aerospace Electrical Connectors (1)

Electrical connectors and their components are important supporting interface components for aerospace system engineering, scattered in various systems and parts, and are responsible for the transmission of signals and energy. The connection performance is directly related to the safe and reliable operation of the entire system.

A variety of circuits are formed by interconnecting electrical connectors, from high frequency to low frequency, from round to rectangular, from high current connectors through hundreds of amperes to high density connectors through weak signals, from ordinary printed circuit board connectors To special connectors such as rapid separation and shedding, almost all types of electrical connectors have been widely used in aerospace system engineering.

The key components in the tactical missile body, such as the seeker, fighter, engine, and autopilot, all use electrical connectors as the basic components to make a complete weapon interconnection system with hundreds of thousands of contact cable networks. If a contact fails, it will cause the entire weapon system to fail.

The reliability of electrical connectors includes both inherent reliability and operational reliability.

1. Inherent Reliability

The inherent reliability of the electrical connector generally refers to the reliability of the electrical connector when it is manufactured. It depends on many factors such as the design, process, manufacturing, management and raw material performance of the electrical connector.

After the electrical connector is manufactured, its failure mode and failure mechanism have been fixed, so only on the basis of reliability design, the production line should be strictly guaranteed to adopt reliable technical measures (such as strict control of production process, control of production environment conditions, various Quality inspection during the process, etc.) can guarantee the inherent reliability of the electrical connector.

(1) Design reliability

① Reasonable selection

Material selection is an important prerequisite for ensuring the electrical performance and reliability of mil spec electrical connectors. The materials used in electrical connectors determine the upper limit of operating temperature, and the decisive factors are insulating materials, sealing materials, adhesive materials, and shells for environmentally sealed electrical connectors. Body and contact materials, etc.

Material selection involves the mechanical, electrical, environmental and other performance requirements of the connector and the physical and chemical properties of the material itself. The thermal properties of the material (heat resistance temperature, thermal conductivity, high temperature strength and thermal deformation, etc.) are the main factors that must be considered in the design. The electrical connector insulator uses different insulating materials, and its electrical properties such as insulation withstand voltage are also significantly different. When selecting the electrical connector housing and contacts, in addition to considering electrical conductivity, thermal conductivity, and structural rigidity, mutual compatibility and the electrochemical compatibility and hardness matching of the contact materials should also be considered.

②Structure type

The structure type is an important factor that determines the reliability of the product. The reasonable structure type not only avoids the wrong insertion, but also improves the stability of the structure.

(2) Process reliability

The processing technology of the housing, the injection molding and adhesive bonding technology of the insulator, the forming and gold plating process of the contact, the assembly process of the electrical connector and the termination process with the cable, etc., are very important to the inherent reliability of the product.

Gold-plated contacts are manually barrel-plated, which often results in a partial oxidation of the inner wall of the individual jacks, and an ultrasonic gold plating production line is introduced, and the thickness of the gold plating layer is strictly monitored by instruments to form a uniform film on the inner wall, which improves contact reliability.

(3) Inspection reliability

The micro electrical connectors are strengthened in each key process, and through strict process screening, reject the defective products. In the delivery test, in addition to checking the conventional electrical performance indicators, 100% appearance quality inspection should also be carried out, especially the inspection of excess materials is very important. In addition to visual inspection and the aid of a magnifying glass, a stereo microscope can be used to determine the nature of the defect if necessary.

During the delivery test and the second supplementary screening process, the quality level specified in the standard must be strictly controlled. When the failure rate is exceeded, each batch of products should be analyzed for failure, the cause of failure should be identified, and effective improvement measures should be taken.

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