Case: Replicating a Historic Bell with Traditional Sand Molds
案例：博物馆古钟复制的砂型合范工艺
标签：古钟复制, 刮板造型, 地坑造型, 调音, 博物馆
苏州某工坊为博物馆复制明代铜钟（高 1.8 m、重 1.2 t）采用地坑砂型：外范分 8 圈以刮板车制（型砂粒度 70/140、湿压强度 90–120 kPa），钟体内芯刮板成形并预留 3 mm 音厚加工量。浇注锡青铜 ZCuSn10Zn2 约 1.5 t，浇温 1150℃，顶注式雨淋浇口防冲砂。铸后钟腔内磨削调音去除 60–80 kg，正敲与侧敲频率误差控制在 ±1 Hz 以内，完全满足陈列演奏要求。
A Suzhou workshop replicated a Ming bell (1.8 m tall, 1.2 t) for a museum using a pit mold: the outer mold was swept in eight ring sections (70/140 sand, green strength 90–120 kPa), while the inner core was sweep-formed with 3 mm machining allowance on the sounding wall. About 1.5 t of ZCuSn10Zn2 tin bronze was poured at 1150°C through a top shower gate to prevent sand wash. Post-cast tuning removed 60–80 kg from the inner surface, holding strike-note deviations within ±1 Hz for both principal and secondary strikes. ---