In the field of sheet metal processing, the shrinkage process is a common forming process, widely used in industries such as automotive, aviation, home appliances, and electronic equipment. The shrinkage process mainly uses molds or mechanical devices to locally shrink the opening part of the sheet metal parts to meet specific size and shape requirements. However, due to the inherent ductility and springback characteristics of sheet metal materials, as well as the complexity of process parameters, controlling the shrinkage accuracy has become a challenging task. This article will discuss how to effectively control the size accuracy of sheet metal shrinkage processes from aspects such as material selection, mold design, equipment accuracy, process parameters, and detection methods.



Firstly, reasonable material selection and pretreatment is the foundation of ensuring shrinkage accuracy. Different sheet metal materials have different mechanical properties, such as yield strength, elongation, and elastic modulus, which directly affect the flow and springback of the material during the shrinkage process. Therefore, appropriate materials should be selected according to product requirements at the design stage, and necessary annealing or surface treatment should be carried out on the materials to improve their forming properties.



Secondly, mold design is one of the key factors affecting shrinkage accuracy. The working part of the mold should be designed accurately according to the flow characteristics of the material. Usually, molds with progressive structures or guided structures are adopted, which help the material to deform uniformly. In addition, the surface roughness of the mold cavity should also be controlled within a reasonable range. Too rough a surface will increase friction resistance, leading to uneven forming; too fine may affect the demolding efficiency.



Third, the accuracy and stability of the equipment have a direct impact on the quality of shrinkage. The use of high-precision hydraulic presses or servo presses can achieve more stable pressing force and displacement control, reducing dimensional deviation caused by equipment error. At the same time, regular calibration and maintenance of the equipment to ensure its good operating condition is also an important link in improving product quality.



Fourth, reasonable setting of process parameters is the core of ensuring shrinkage accuracy. This includes optimization and adjustment of factors such as pressing speed, stroke control, pressure setting, and lubrication conditions, all of which need to be adjusted according to specific materials and product shapes. In particular, the setting of springback compensation often requires continuous parameter adjustment through CAE simulation analysis or trial molding experience to achieve the expected size.



Finally, establishing a complete detection system is an important means to improve the level of process control. The use of advanced detection equipment such as coordinate measuring machines and laser scanners can make precise measurements of the key dimensions of shrinkage parts. At the same time, combined with statistical process control (SPC) methods, the production process can be monitored in real time, and deviations can be discovered and corrected in a timely manner, thus achieving quality stability in mass production.



In summary, to achieve high-precision control of the sheet metal shrinkage process, it is necessary to carry out systematic optimization from multiple aspects such as materials, molds, equipment, process, and detection. Only on the basis of collaborative cooperation at all levels can stable and efficient high-precision shrinkage processing be truly realized.