Optimizing the contact resistance of terminal connection wires is crucial for ensuring efficient signal transmission, involving multiple factors such as material selection, structural design, manufacturing processes, and environmental adaptability. Even small changes in contact resistance can cause signal attenuation, distortion, or even equipment malfunction. Therefore, systematic optimization is necessary to reduce resistance and improve stability, ensuring reliable transmission of data, power, or high-frequency signals.
Material selection is fundamental to contact resistance optimization. The contact interface between the terminal and the wire requires highly conductive materials, such as copper alloys (e.g., brass, phosphor bronze) or plating metals (e.g., gold plating, silver plating). Copper alloys are the mainstream choice due to their excellent conductivity, mechanical strength, and corrosion resistance, while plating further reduces the risk of chemical corrosion at the contact surface by forming a dense oxide film or inert metal layer. For example, gold plating effectively resists sulfide corrosion and is suitable for high-humidity or industrially polluted environments; silver plating, due to its low contact resistance, is often used in high-frequency signal transmission scenarios. Matching material hardness is equally critical; excessively hard plating may lead to contact surface wear, while excessively soft plating can easily cause plastic deformation, both of which increase contact resistance.
The geometry of the contact surface directly affects the resistance value. The contact area between the terminal and the wire needs to be increased to reduce resistance. Common designs include multi-point contact, flexible crimping, or surface texturing. For example, using a serrated or wavy contact surface increases friction, preventing loosening while increasing the actual number of contact points; flexible terminals compensate for assembly errors through their own deformation, ensuring long-term pressure stability. Furthermore, the flatness and smoothness of the contact surface must be strictly controlled. Microscopic irregularities can shorten the current path, forming localized hot spots, increasing resistance and accelerating material aging.
The crimping process is a crucial manufacturing step for controlling contact resistance. Crimping the terminal and wire requires applying precise pressure using specialized tools to cause plastic deformation of the metal and form an airtight connection. Insufficient pressure will lead to loosening of the contact surface and increased resistance; excessive pressure may damage the wire insulation or cause the terminal to crack. High-quality crimping must meet the "three pressures" principle: crimping height, crimping width, and crimping shape must conform to design specifications, ensuring uniform metal flow and the absence of cracks or burrs. Some high-end terminals utilize cold-press welding technology, using high pressure to form a metallurgical bond between metal atoms, further reducing contact resistance.
Environmentally adaptable design can delay contact resistance degradation. Terminal connection wires are often exposed to high temperatures, humidity, salt spray, or vibration environments, which can cause oxidation, corrosion, or fretting wear. For example, in coastal areas, salt spray accelerates electrochemical corrosion of metal surfaces, forming a high-resistivity oxide layer; in vibration scenarios, repeated small displacements can cause contact surface wear, leading to resistance fluctuations. To address these issues, it is necessary to isolate the environmental medium through sealing structures (such as rubber sleeves or potting compounds) or use self-lubricating materials (such as tin plating) to reduce friction. Furthermore, regular maintenance (such as cleaning contact surfaces and tightening terminals) is also crucial for maintaining low resistance.
The impact of signal frequency on contact resistance cannot be ignored. During high-frequency signal transmission, parasitic capacitance and inductance of the contact surface can cause signal reflection or attenuation. In such cases, it is necessary to optimize the contact structure to reduce impedance discontinuities. For example, using a coaxial structure or flat cable design can reduce electromagnetic interference; the contact surface plating should be made of a low-dielectric-constant material to avoid signal energy loss. For digital signals, the stability of contact resistance is more important than its absolute value, and vibration-resistant design is necessary to prevent timing errors.
Long-term reliability is the ultimate goal of contact resistance optimization. Terminal connection wires must maintain low resistance throughout the entire device's lifespan, requiring consideration of material fatigue, creep, and aging factors from the design stage. For example, flexible terminals need to have improved fatigue resistance through heat treatment processes; contact surface plating must have self-healing capabilities, maintaining conductivity even after minor wear. Furthermore, standardized testing (such as salt spray testing and vibration testing) verifies design reliability, ensuring the product can withstand complex operating conditions.
Optimizing the contact resistance of terminal connection wires requires the integrated application of materials science, mechanical design, manufacturing processes, and environmental engineering to achieve the goals of low resistance, high stability, and long lifespan. This process not only concerns the performance of individual terminals but also affects the signal integrity of the entire system, serving as a fundamental guarantee for the reliable operation of electronic equipment.
