Polyurethane Pad-assisted Low-mark Sinking
聚氨酯软垫辅助下凹低痕成形
标签：聚氨酯垫, 低痕成形, 软模, 下凹, 新模具材料
在凹模窝与铜片之间垫 3–5 mm 厚聚氨酯垫（邵氏 A80），用木锤或尼龙锤敲击，软垫将冲击均匀分散，工件表面几乎不留锤痕，可省去大量后续修光。适用于 0.5–1.2 mm 铜板初成型，成形后仍需入钢凹模精校一次。聚氨酯硬度选 A70–A90：太软走料慢、太硬痕重。每敲 30–40 次将工件旋转 30–60°，保证走料均匀不起定向皱纹。
Place a 3–5 mm polyurethane pad (Shore A80) between the dapping die and the copper disc, then strike with a rawhide or nylon hammer. The pad spreads the impact so the surface stays nearly mark-free, saving much clean-up. Suited to 0.5–1.2 mm sheet for initial forming; finish-calibrate in a steel die afterwards. Pick A70–A90: too soft moves metal slowly, too hard marks. Rotate the work 30–60° every 30–40 blows to keep flow even and avoid directional wrinkles. ---