Root-cause Tree: Wrinkle, Tear or Springback?
深冲废品根因树：起皱-破裂-回弹决策
标签：根因树, 决策表, 起皱, 破裂, 回弹
深冲废品按"部位+形貌"决策表定位：①凸缘外缘大波浪皱→压边力低，压边力按 1.2 倍防皱最小值上调；②侧壁纵向裂纹且断于底部圆角→拉深比超限或凹模圆角过小（紫铜凹模 R ≥6t）；③杯口高低耳→板料 Δr 大，换交叉轧制板或旋转坯料方向；④卸载后碗口张开超差→回弹，末道次加 10% 保压或增加底部整形工位。某 1 mm H62 水杯壳试模期套用决策表后，每轮废品从 20% 降到个位数，试模周期缩短一半。
Sort drawing scrap by location plus appearance: (1) big waves at the flange rim — blank-holder force too low; raise to 1.2× the anti-wrinkle minimum. (2) Longitudinal wall cracks breaking at the base radius — draw ratio exceeded or die radius too small (R ≥6t in copper). (3) Eared rim — high Δr; switch to cross-rolled stock or rotate the blank. (4) Rim flaring after unload — springback; add 10% dwell on the last pass or an ironing/coining station. One 1 mm H62 tumbler job dropped per-round scrap from 20% to single digits using this table.