Against the backdrop of new energy vehicles developing toward high integration and high reliability, automotive connectors—acting as "neural nodes" of electrical systems—rely heavily on the manufacturing quality of injection molds for their precision and stability. Compared with ordinary injection molds, automotive connector injection molds need to meet requirements such as thin walls (0.4-0.8mm), multi-cavity design, and adaptation to extreme working conditions. Below are key manufacturing points shared from four core technical dimensions:
High-temperature area adaptation: For high-temperature environments such as engine compartments, LCP + 30% glass fiber (GF) composite materials are preferred. Their linear shrinkage rate can be as low as 0.05%, and heat distortion temperature exceeds 260℃, avoiding dimensional deviation at high temperatures;
High-voltage scenario adaptation: High-voltage connectors for new energy vehicles (e.g., battery pack connectors) require excellent insulation. PA46/PA66 are mainstream choices, with dielectric strength ≥20kV/mm. Combined with fluoroplastic coating, they can achieve a volume change rate of ＜1% after 72 hours of fuel immersion, meeting chemical corrosion resistance requirements;
Mold base material selection: As core stress-bearing components of the mold, cores and cavities need to balance hardness and toughness. SKD61 mold steel is usually used, which can reach a hardness of 52-54HRC after quenching, ensuring no significant wear or deformation within 500,000 molding cycles.
Cavity structure optimization: 1×2 or 1×4 cavity design is adopted, which not only ensures single-cavity molding precision but also improves production efficiency. At the same time, an insert-type structure is introduced to split complex cavities into independent inserts for processing, which not only reduces overall processing difficulty but also facilitates later precision correction and maintenance. The core gap is strictly controlled within 0.4mm;
Gating system design: Submarine side gates are selected to realize automatic separation of runners and products after molding, reducing subsequent processing procedures. Combined with fan-shaped runner design, the melt flow rate in the runner is uniform (5-10m/s), avoiding weld lines caused by uneven flow rate—such defects easily lead to fracture risks of connectors under vibration conditions;
Guiding and positioning enhancement: A combined structure of "tapered positioning + double guide pillars" is adopted. Tapered positioning can quickly calibrate the mold clamping center, and double guide pillars further improve guiding precision, making the clamping deviation ＜0.002mm, meeting MT1-MT2 tolerance standards and ensuring precise matching between pin holes and terminals.
Temperature control: The barrel adopts segmented temperature control. The front section temperature is set to 260-280℃ (adapting to the melting needs of materials such as PA and LCP) to avoid material degradation caused by local overheating; the mold temperature is regulated through conformal cooling channels, maintained at 60-80℃, and the distance between the cooling channel and the product surface is controlled at 3-5mm to ensure uniform cooling, with a temperature difference ≤±5℃, reducing internal stress caused by uneven cooling;
Pressure and speed matching: High-pressure (80-120MPa) and rapid filling are used in the filling stage to ensure full filling of thin-walled areas; after entering the packing stage, the pressure is reduced to 40-60MPa and maintained for 5-10s to compensate for 5%-8% volume shrinkage of the melt, avoiding sink marks on products; at the same time, "segmented speed" control is adopted—50% speed in the initial filling stage and 30% speed in the middle and later stages—to reduce the impact of shear heat on material performance;
Cycle optimization: CAE mold flow analysis software is used to simulate the melt flow and cooling process, and optimize molding parameters—for example, by adjusting the packing time and cooling time, the molding cycle can be reduced from the traditional 45s to 35s, improving production efficiency while ensuring precision.
Dimensional precision inspection: A coordinate measuring machine (CMM) is used for 100% sampling inspection of key dimensions such as pin hole positions and fitting gaps, with a measurement accuracy of ±0.005mm, ensuring that the dimensional deviation of each product is within the design allowable range;
Environmental adaptability test: A 10-2000Hz sweep frequency vibration test is conducted to simulate the vibration conditions during vehicle operation and verify the structural stability of connectors; after 96 hours of 5% NaCl salt spray test, the surface insulation resistance drop should be ＜10% to ensure compliance with corrosion resistance standards;
Long-term life verification: Simulate actual usage scenarios, conduct 5,000 insertion and extraction tests (corresponding to 10 years of vehicle usage frequency), and at the same time, conduct high-low temperature cycle aging tests (-40℃~150℃ alternating) to verify the performance attenuation of products after long-term use and ensure stable signal transmission.
As automotive electronic architectures evolve toward domain controllers and central computing platforms, connector molds will further develop in the direction of "ultra-precision and multi-material co-injection". Mastering the above core technical points is the key to achieving breakthroughs in mold performance.
