Performance Analysis And Manufacturing Process of Connectors

A connector is also known as a connector. Build a communication bridge between blocked or isolated circuits within the circuit, allowing current to flow and enabling the circuit to achieve its intended function. Also known as connectors and sockets in China, they generally refer to electrical connectors. A device that connects two active devices to transmit current or signals.

Performance of connectors

1. Mechanical performance: In terms of connection function, insertion and extraction force is an important mechanical performance.

The insertion and extraction forces are divided into insertion force and extraction force (also known as separation force), and their requirements are different. In relevant standards, there are provisions for maximum insertion force and minimum separation force, which indicates that from a usage perspective, the insertion force should be small (resulting in sructures with low insertion force LIF and no insertion force ZIF), and if the separation force is too small, it will affect the reliability of contact.

Another important mechanical property is the mechanical life of the connector. Mechanical life is actually a durability indicator, referred to as mechanical operation in the national standard GB5095. It is evaluated based on whether the connector can complete its connection function (such as contact resistance value) normally after a specified insertion and extraction cycle, with one insertion and one extraction as a cycle. The insertion and extraction force and mechanical life of connectors are related to the contact structure (positive pressure), the coating quality of the contact area (sliding friction coefficient), and the accuracy of the contact arrangement size (alignment).

2. Electrical performance: The main electrical performance of the connector includes contact resistance, insulation resistance, and electrical strength.

① Contact resistance: High quality electrical connectors should have low and stable contact resistance. The contact resistance of connectors varies from a few milliohms to tens of milliohms.

② Insulation resistance: An indicator that measures the insulation performance between the contacts of an electrical connector and between the contacts and the shell, with an order of magnitude ranging from hundreds of megaohms to thousands of megaohms.

③ Dielectric strength: also known as voltage resistance or dielectric withstand voltage, it represents the ability of a connector to withstand the rated test voltage between contacts or between contacts and the shell.

④ Other electrical performance: Electromagnetic interference leakage attenuation is used to evaluate the electromagnetic interference shielding effect of the connector, and electromagnetic interference leakage attenuation is used to evaluate the electromagnetic interference shielding effect of the connector, usually tested in the frequency range of 100MHz~10GHz.

For RF coaxial connectors, there are also electrical indicators such as characteristic impedance, insertion loss, reflection coefficient, and voltage standing wave ratio (VSWR). Due to the development of digital technology, a new type of connector, high-speed signal connector, has emerged to connect and transmit high-speed digital pulse signals. Correspondingly, in terms of electrical performance, in addition to characteristic impedance, some new electrical indicators have also emerged, such as crosstalk, transmission delay, and delay.

3. Environmental performance: Common environmental performance includes resistance to temperature, humidity, salt spray, vibration, and impact.

① Temperature resistance: Currently, the maximum working temperature of connectors is 200 ℃ (except for a few high-temperature special connectors), and the minimum temperature is -65 ℃. Due to the heat generated by the current at the contact point during the operation of the connector, resulting in a temperature rise, it is generally believed that the working temperature should be equal to the sum of the ambient temperature and the contact temperature rise. In certain specifications, the maximum allowable temperature rise of connectors under rated operating current is clearly specified.

② Moisture resistance: The invasion of moisture can affect the insulation performance of connectors and corrode metal parts. The constant damp heat test conditions are relative humidity of 90%~95% (up to 98% according to product specifications), temperature of+40&# 177; 20 ℃, test time according to product regulations, minimum 96 hours. The alternating damp heat test is more rigorous.

③ Salt spray resistance: When the connector works in an environment containing moisture and salt, the surface treatment layer of its metal structure and contact parts may produce electrochemical corrosion, which affects the physical and electrical performance of the connector. In order to evaluate the ability of electrical connectors to withstand this environment, a salt spray test is specified. It suspends the connector in a temperature controlled test chamber and sprays out a specified concentration of sodium chloride solution with compressed air to form a salt mist atmosphere. The exposure time is specified by the product specifications and is at least 48 hours.

④ Vibration and shock: Resistance to vibration and shock is an important performance of electrical connectors, especially in special application environments such as aviation and aerospace, railway and road transportation. It is an important indicator for testing the robustness of the mechanical structure and electrical contact reliability of electrical connectors. There are clear provisions in the relevant test methods. The peak acceleration, duration, and pulse waveform of the impact test should be specified, as well as the time for electrical continuity interruption.

⑤ Other environmental performance: According to usage requirements, other environmental performance of electrical connectors include sealing (air leakage, liquid pressure), liquid immersion (resistance to specific liquids), low air pressure, etc.

Benefits of connectors

1. Improve the production process: Simplify the assembly process of electronic products with connectors. It also simplifies the batch production process;

2. Easy to repair: If a certain electronic component fails, it can be quickly replaced when a connector is installed;

3. Easy to upgrade: With technological progress, when connectors are installed, the components can be updated and replaced with new and more complete components;

4. Improving Design Flexibility: Using plugins allows engineers greater flexibility in designing and integrating new products, as well as in composing systems with components.

The production process of connectors

The production process of plug-in components mainly includes the manufacturing process of parts and the assembly process of products.

The plug-in component mainly consists of contact parts, insulation parts, and structural components The manufacturing process of the parts mainly involves the processing technology of these three components Such as mechanical processing, stamping, injection molding, die-casting, surface coating, etc

With the increasing demand for plug-in components, the production batch of parts is relatively large. Therefore, the machining of parts should continuously improve the degree of mechanization and automation, and more efficient specialized equipment should be used to gradually achieve automated production methods for plug-in components

The contact parts are manufactured using either turning or punching processes. In large-scale production, turning is mainly done using longitudinal cutting automatic lathes, with the direction of using composite multifunctional automatic machine tools to complete multiple processes on the equipment to avoid secondary processing of the parts, thereby improving the machining accuracy and production efficiency of the parts. For small-scale production, precision instrument lathes can be used for processing

The characteristic of punching contact parts is that they are more efficient than turning, but their accuracy is slightly lower than turning the body At present, due to the continuous improvement of the accuracy of molds and stamping equipment, the accuracy of punching contact parts has also been greatly improved. The processes used include: using a cold heading machine to manufacture pins, using a multi-station punching machine to manufacture sockets, and using a bending machine to manufacture spring contact parts

Plastic insulation components are mostly made of thermoplastic or thermosetting plastics according to their usage requirements Thermoplastic insulation components have achieved closed automation production, which is beneficial for improving work efficiency and reducing environmental pollution. Thermosetting plastics also recommends the use of injection materials and processes

Structural components include metal shells, plastic shells, and other structural parts, and their processing processes include die-casting, injection molding, cold extrusion, extrusion casting, and mechanical processing. The use of modified aluminum alloy cold extrusion shell technology can achieve the benefits of high strength, good accuracy, and high efficiency in processing

Common faults of connectors

There are three common forms of fatal faults in wiring terminals:

1. Poor contact

The metal conductor inside the terminal is the core component of the terminal, which transmits voltage, current, or signals from external wires or cables to the corresponding contacts of the corresponding connectors. Therefore, the contact parts must have excellent structure, stable and reliable contact retention force, and good conductivity. Due to the unreasonable design of the contact structure, incorrect material selection, unstable mold, oversized machining, rough surface, unreasonable surface treatment processes such as heat treatment and electroplating, improper assembly, harsh storage and use environment, and improper operation, poor contact can be caused at the contact and mating parts of the contact.

2. Poor insulation

The function of an insulator is to maintain the correct alignment of the contacts and to insulate them from each other, as well as from the shell. Therefore, insulation components must have excellent electrical, mechanical, and process forming properties. Especially with the widespread use of high-density and miniaturized terminal blocks, the effective wall thickness of insulators is becoming thinner and thinner. This puts forward stricter requirements for insulation materials, injection mold accuracy, and molding process. Due to the presence of metal residues, surface dust, solder contamination, moisture, organic material precipitates, and harmful gas adsorption films on the surface or inside of the insulator, they fuse with the surface water film to form ionic conductive channels, absorb moisture, mold, and aging insulation materials, all of which can cause insulation defects such as short circuits, leakage, breakdown, and low insulation resistance.

3. Poor fixation

Insulators not only serve as insulation, but also provide precise alignment and protection for extended contacts. They also have the function of installation positioning, locking and fixing on the equipment. Poor fixation may affect the reliability of contact, resulting in instant power outage. The most serious issue is product disassembly. Disassembly refers to the abnormal separation between plugs and sockets, as well as between pins and sockets, caused by unreliable structure due to material, design, process, and other reasons when the wiring terminal is in the plug-in state, which will cause serious consequences such as power transmission and signal control interruption in the control system. Due to unreliable design, incorrect material selection, improper selection of forming process, poor quality of heat treatment, mold, assembly, fusion and other processes, and inadequate assembly, poor fixation can all be caused.

In addition, poor appearance caused by peeling, corrosion, bruises, plastic shell flash, breakage, rough processing of contact parts, deformation, and other reasons of the coating, as well as poor interchangeability caused by oversized positioning and locking fit size, poor processing quality consistency, and excessive total separation force, are also common and frequently occurring diseases. These types of faults can generally be detected and eliminated in a timely manner during inspection and use.