Electric Molds Industry Product Application Case: Design and Application of Special Electric Molds for OBC Housings-News

Electric molds are a new type of mold equipment that achieves high-precision molding relying on servo motor drive and intelligent closed-loop control technology. Their core advantages lie in the precise controllability of actions such as ejection, mold adjustment, and core pulling, high automation integration, and strong operational stability, making them a core production support in high-end manufacturing fields such as new energy and electronics. As a key component of the new energy vehicle charging system, the On-Board Charger (OBC) housing is responsible for protecting internal circuits, heat dissipation, electromagnetic shielding, and precise assembly, imposing strict requirements on molding accuracy, structural stability, and mass production consistency. Traditional hydraulic molds are prone to problems such as uneven ejection force and insufficient mold adjustment accuracy, while electric molds, through servo drive and intelligent regulation, can perfectly meet the precision molding needs of OBC housings. Taking the OBC housing of new energy vehicles as the target product, this article elaborates on the application details, technical points, and practical value of electric molds, providing a reference for the development of molds for similar products.

I. Product Characteristics and Core Requirements for Electric Molds

The OBC housing focused on in this case is an integrated aluminum alloy structure with an overall size of 280mm×180mm×80mm and a main wall thickness of 2.2mm. Its surface integrates multiple groups of heat dissipation fins (wall thickness 1.5mm), circuit module mounting posts, and bolt fixing holes, with adaptive interfaces reserved for the vehicle body and wiring harnesses. The positional tolerance of the mounting holes must be controlled within ±0.015mm to ensure precise docking of internal components. The product is made of ADC12 aluminum alloy, which must meet the temperature resistance (-40℃ to 125℃), vibration resistance, and electromagnetic shielding requirements of new energy vehicle components. The surface must be free of blowholes, shrinkage marks, deformation, and other defects, with a tensile strength ≥220MPa and a heat dissipation coefficient ≥100W/(m·K).

The core requirements for the corresponding electric mold are clear: relying on a servo electric drive system to achieve millimeter-level control of ejection and core pulling actions to avoid housing deformation due to uneven force; the electric mold adjustment mechanism must achieve an accuracy of ±0.005mm to ensure the consistency of multi-cavity products; integrate intelligent temperature control and pressure monitoring modules to adapt to the high-temperature molding needs of aluminum alloy die casting; the mold must have automatic linkage capability to meet the mass production demand of over 1 million new energy vehicle components per year; the mold material must be high-temperature resistant and thermal fatigue resistant, with a service life of not less than 800,000 cycles, balancing precision and economy.

II. Key Design Points of Electric Molds for OBC Housings

The mold adopts an overall two-plate structure suitable for horizontal die casting machines, designed with a 4-cavity symmetrical layout. All core drive components are equipped with servo motors. The mold material is H13 hot work die steel, which undergoes quenching and tempering, nitriding, and surface ceramic coating treatments to improve high-temperature wear resistance and oxidation resistance. The core design points focus on the advantages of electrification:

Design of Electric Drive System: The ejection mechanism adopts dual servo motor synchronous drive, matched with precision ball screw transmission. The ejection force can be accurately adjusted within the range of 5-8kN, and the ejection speed is adjustable in segments (0.5-2mm/s). For the weak heat dissipation fin area of the housing, multiple uniform ejection points are set to avoid local deformation due to uneven force. The core-pulling mechanism adopts electric rotary core pulling, where the servo motor drives the gear set to realize the core-pulling action, with the core-pulling stroke accuracy controlled within ±0.01mm, adapting to the molding and demolding of complex buckle structures inside the housing. Compared with traditional hydraulic core pulling, the response speed is increased by 30%, and there is no risk of hydraulic oil leakage.

Design of Electric Mold Adjustment and Temperature Control: An electric mold adjustment mechanism is adopted, which drives the mold adjustment screw through a servo motor to realize precise adjustment of the mold closing gap. With the positioning feedback of the grating ruler, the mold adjustment accuracy reaches ±0.005mm, ensuring the synchronous molding consistency of the four cavities. The temperature control system is equipped with an electric proportional valve and intelligent sensors to monitor the cavity temperature in real time (set temperature 280-320℃), with the temperature fluctuation controlled within ±2℃. By electrically adjusting the water channel flow rate, it adapts to the solidification characteristics of the aluminum alloy melt and reduces shrinkage marks and blowhole defects of the housing.

Design of Gating and Exhaust System: An electrically controlled hot runner gating system is adopted, where the servo motor drives the needle valve gate, and the switching timing is accurately controllable (error ≤0.05s), ensuring uniform filling of the four cavities with melt and avoiding local material shortage. The exhaust system is equipped with micro exhaust grooves at the highest point of the cavity and the gaps of the heat dissipation fins, matched with an electric auxiliary exhaust pump to quickly discharge air and volatile substances in the cavity, controlling the defect rate below 0.3%. At the same time, the exhaust pressure is electrically monitored to feed back the molding status in real time.

III. Mold Manufacturing Process and Quality Control

The manufacturing of electric molds for OBC housings follows the principle of "high-precision machining + integrated debugging of electric components", with the process flow: material pretreatment → 5-axis CNC milling → EDM precision machining → electric component assembly → intelligent system debugging → mold testing and optimization → finished product acceptance. The whole process focuses on electrified precision control, balancing structural accuracy and operational stability.

High-Precision Machining Link: After quenching and tempering treatment, H13 steel is processed into cavity and core blanks by 5-axis CNC milling, matched with electric positioning fixtures, with the machining accuracy controlled within ±0.003mm, focusing on ensuring the size of heat dissipation fins, the position of mounting holes, and the accuracy of cavity curved surfaces; EDM (Electrical Discharge Machining) is used to process complex buckle structures inside, using copper electrodes for discharge forming, reducing the surface roughness to Ra≤0.8μm; before the assembly of electric components, precision calibration is performed on core components such as servo motors and ball screws to ensure the transmission gap ≤0.002mm.

Debugging and Assembly of Electric System: During assembly, a PLC intelligent control system is integrated to realize the linkage debugging of electric ejection, core pulling, and mold adjustment actions. Parameters are set through the touch screen and multiple molding schemes are stored to adapt to the production of different batches of products. Multi-dimensional sensors such as pressure, temperature, and displacement are installed to collect the operation data of electric components in real time. If there is a parameter deviation, the system automatically triggers servo regulation to ensure stable operation of the mold. The seals are made of high-temperature resistant fluororubber to prevent aging and leakage under high-temperature conditions, meeting the hygiene and safety standards of new energy vehicle components.

Mold Testing and Optimization: A 2000kN electric die casting machine is selected for mold testing, with the melt temperature set at 650-670℃, the electric gate switching time at 0.8s, the ejection speed at 1.2mm/s, and the cooling time at 25s. After mold testing, a coordinate measuring machine is used to detect key dimensions, and a laser interferometer is used to calibrate the operation accuracy of electric components. For the slight deformation of heat dissipation fins, the electric ejection points and speed parameters are optimized. After optimization, the product qualification rate reaches 99.7%, and the assembly adaptability is 100%.

IV. Application Value and Industry Adaptability

After the electric mold is put into production, the single-shift output reaches 3,200 OBC housings, adapting to the mass production demand of 800,000 OBC units per year. Compared with traditional hydraulic molds, the production efficiency is increased by 25%, the scrap rate due to precision optimization is reduced to below 0.3%, and the unit product mold sharing cost is reduced by 18%. The servo electric system equipped with the mold can realize 24-hour continuous stable operation, with a fault shutdown rate of less than 0.5%, greatly reducing the shutdown loss during mass production and meeting the large-scale and high-efficiency production demands of the new energy vehicle industry.

Practical application verification shows that the OBC housings formed by the electric mold have stable dimensional accuracy, close fit between mounting holes and internal components, and qualified heat dissipation performance, with no deformation or cracking after 1,000 hours of temperature and vibration resistance testing. At the same time, the automatic integration capability of electric molds can be directly connected to the robot loading and unloading system of the production line, reducing manual intervention and improving the level of production intelligence, which is in line with the trend of new energy vehicle manufacturing towards "precision, automation, and greenization". In addition, electric molds have no hydraulic oil leakage problems, reducing environmental treatment costs and further adapting to the green production requirements of the high-end manufacturing field.

Conclusion

The design and application of special electric molds for OBC housings accurately meet the core requirements of the new energy vehicle industry for high precision, high stability, and high mass production efficiency of components, giving full play to the unique advantages of electric molds in servo drive, intelligent regulation, and automatic integration. With the rapid upgrading of industries such as new energy vehicles and high-end electronics, electric molds will further integrate digital design and AI intelligent monitoring technologies, optimize multi-dimensional parameter linkage control capabilities, adapt to the molding needs of more complex structures and high-performance products, and become a core equipment support for promoting the quality improvement, efficiency enhancement, and green upgrading of high-end manufacturing.