As a critical component for transmitting current or signals in electronic devices, the proper control of the bending radius of terminal connection wires is essential to ensuring the integrity of their internal structure. An excessively small bending radius can lead to conductor breakage, insulation damage, or shielding failure, thereby affecting signal transmission stability and even causing safety hazards. Therefore, it is necessary to comprehensively ensure their bending performance from multiple dimensions, including material selection, structural design, process control, and usage specifications.
The choice of conductor material is fundamental. Terminal connection wires typically use tin-plated copper or bare copper as conductors, as these materials combine good conductivity and fatigue resistance. The tin plating layer prevents copper oxidation, reduces contact resistance, and improves the conductor's flexibility, making it less prone to breakage during bending. Furthermore, the conductor's wire diameter and strand count must be matched to the bending requirements. A multi-strand fine wire stranded structure can better distribute stress than a single thick wire, reducing the risk of breakage during bending. For example, in scenarios requiring frequent bending, using conductors with 7 or 19 strands of fine copper wire can significantly improve bending resistance.
The material and thickness design of the insulation layer directly affect its resistance to breakage during bending. Highly elastic and wear-resistant insulating materials, such as heat-resistant PVC or TPU, provide sufficient cushioning during bending, preventing relative displacement between the conductor and the insulation layer. Simultaneously, the insulation layer thickness must be determined comprehensively based on the conductor wire diameter and bending radius; too thin an insulation layer can easily lead to breakage, while too thick an insulation layer may limit bending flexibility. For example, in applications requiring small-radius bending, semi-rigid insulating materials can be used, balancing flexibility and insulation performance by adjusting their hardness and thickness.
Optimizing the shielding layer structure is crucial for ensuring signal integrity. For terminal connection wires requiring electromagnetic interference immunity, the shielding layer typically employs tin-plated soft copper wire braiding or cross-rolling processes. Braided shielding layers offer higher coverage and flexibility, suitable for dynamic bending scenarios, while cross-rolled shielding layers are more suitable for static or low-frequency bending environments. During bending, the density and tightness of the shielding layer must be moderate; excessive tightness may lead to breakage, while excessive looseness may reduce shielding effectiveness. By optimizing the braiding angle or cross-rolling tension, the continuity and stability of the shielding layer can be ensured after bending.
The crimping process between the terminal and the conductor directly affects bending performance. Parameters such as crimp height, flare size, and tail length must strictly conform to standards to ensure the connection strength between the conductor and the terminal. If the crimp height is too small, the conductor may break; if it is too large, it may lead to poor contact or loosening. Furthermore, the conductor in the crimped area must be horizontal and free of twisting to avoid stress concentration during bending. For example, after crimping, the length of the conductor end extending beyond the crimp frame must be controlled within a reasonable range; too long may interfere with insertion and removal, while too short may reduce connection reliability.
The standardized use of the bending radius is the last line of defense for ensuring long-term stability. Different specifications of terminal connection wires correspond to different minimum bending radii, which are usually determined by the conductor diameter, insulation thickness, and shielding structure. During use, forced bending or repeated bending at the same location should be avoided to prevent material fatigue. For example, when wiring equipment, sufficient bending space should be reserved, and wire clips or cable ties should be used for fixation to prevent excessive bending of the connection wire due to its own weight or vibration.
Environmental factors also have a significant impact on bending performance. High temperatures can accelerate insulation aging and reduce its flexibility, while low temperatures can make materials brittle and increase the risk of breakage. Therefore, it is necessary to select terminal connection wires with matching temperature resistance ratings based on the application scenario and to strengthen protection in extreme environments. For example, in outdoor or industrial environments, weather-resistant sheathing materials can be used, or protective tubing can be added to reduce the impact of the environment on bending performance.
The bending radius of terminal connection wires must be guaranteed throughout their entire lifecycle, from design and production to use. By rationally selecting materials, optimizing structural design, strictly controlling processes, standardizing usage methods, and considering environmental factors, it is possible to ensure the integrity of its internal structure and stable signal transmission during bending, thereby meeting the stringent reliability and safety requirements of electronic equipment.
