关键词: 桥半壳；冷冲压；外观质量；起皱与材料堆积

Abstract: In response to surface defects such as "extrusion ridges" and "strip indentations" observed during the transition from hot stamping to cold stamping for a specific model of axle housing half-shells, this paper thoroughly investigates their root causes, which are attributed to localized material accumulation and instability due to uneven material flow. By introducing an innovative composite mold design featuring a "curved-surface die" and a "variable-radius punch", a novel method for actively controlling material flow paths is established. This approach effectively coordinates flow velocity differences across regions by reconstructing the initial contact state and stress distribution of the blank and eliminating abrupt stress concentration points along the flow paths. Practical results demonstrate that the method completely eliminates the targeted surface defects, resulting in smooth and flat product surfaces, it has been successfully applied in mass production, providing valuable theoretical insights and a practical reference for the precision cold stamping of similar complex structural components.

Key words: bridge half-shells; cold stamping; appearance quality; buckling and material pile-up