Process design of multi-stage cold forging with small size for ESC solenoid valve parts

ESC’s solenoid valves independently brake each wheel, allowing the vehicle to maintain braking and directional stability. The most important component of the solenoid valve is the armature manufactured by the turning process by a CNC lathe so far. In this study, we propose to use the multi-stage cold forging process as an alternative to reduce manufacturing cost while satisfying dimensional accuracy and performance. To apply the multi-stage cold forging process, the whole forming process is divided into six stages to improve the dimensional accuracy of the outer diameter, full length and slot part of the armature. It is divided into 6 stages, but 6 stages are operated simultaneously in one stroke of forging. Inducing uniform plastic deformation by designing the preform for each stage of the armature slot. Through the proposed process design for the multi-stage cold forging process, the dimensional accuracy of the test product can be improved. The weight of the input material in the turning process can be reduced by 46 % from 3.5 g to 1.9 g by applying the multi-stage cold forging process. In addition, the manufacturing process can be reduced from 2 processes to 1 process, and the production quantity can be increased by 2500 % from 180 ea to 4800 ea per hour.