Defect Root-cause Tree: Wrinkling, Tearing & Springback
浮雕废品根因树：起皱、破裂与回弹
标签：根因树, 起皱, 破裂, 回弹, 废品分析
浮雕废品按"先判位置、再查力、后查料"三步排查：①凸缘起皱→压边力不足或润滑过量，压边压强从 2 MPa 起步、每道次上调 0.5 MPa；②裂纹集中于轮廓圆角→圆角 R 小于 2 倍料厚，或单道次减薄率超 15%；③卸载后浮雕回弹塌陷→道次间未退火（1 mm 紫铜累计变形量达 60% 时须 550 °C 退火），或聚氨酯垫硬度选错（浅纹用 Shore A70、深纹用 A90）。某 1.2 mm 黄铜壁画项目按此树排查后，废品率从 18% 降至 4%。
Diagnose relief scrap in three steps — locate, check forces, check material: (1) flange wrinkles mean low blank-holder pressure or excess lube; start at 2 MPa and step up 0.5 MPa per pass. (2) Cracks at profile radii mean R under 2× gauge, or pass reduction over 15%. (3) Springback flattening after unload means skipped inter-pass anneals (anneal 1 mm copper at 550 °C past 60% cumulative strain) or wrong pad hardness (Shore A70 shallow, A90 deep). One 1.2 mm brass mural job cut scrap from 18% to 4% with this tree.