Root-cause Analysis of Springback and Edge Collapse in Coining
压印回弹与棱角塌陷的根因分析
标签：回弹, 棱角塌陷, 根因分析, 压印
压印件卸载后浮雕深度"缩水"或棱线发圆，主因四项：①坯料退火不足，硬度高于 HV 90 时回弹显著；②单位压强不足，轮廓未压入充分塑性区；③坯径与模腔间隙过大，金属侧向流动泄压；④模具棱口磨损倒圆。诊断顺序：测坯硬度（目标 HV 70–85）→核算单位压强（铜合金通常 600–900 MPa）→观察飞边出现位置判断金属流向。常用补救是二次精压：第一次留 0.02–0.03 mm 余量，第二次只精压棱线区，可挽回 0.05 mm 左右深度。
When relief depth "shrinks" or edges go round after unloading, four causes dominate: under-annealed blanks (above HV 90 springback is pronounced), insufficient unit pressure leaving the relief short of full plastic deformation, excessive blank-to-cavity clearance letting metal escape sideways, and worn radiused die edges. Diagnose in order: check blank hardness (target HV 70–85), verify unit pressure (600–900 MPa for copper alloys), and note where flash forms to read metal flow. The standard rescue is a second coining stroke: leave 0.02–0.03 mm on the first hit, then size only the relief edges—recovering about 0.05 mm of depth.