QC: Thinning Ratio and Roundness of Sunk Work
下凹件减薄率与圆度检测规范
标签：减薄率, 圆度, 检测, 质检
下凹件出厂前建议做双项检测：①减薄率——超声测厚在锅底中心、过渡区、侧壁三点取样，商用器皿减薄上限 20%，承压件收紧到 15%；②圆度——用 π 带（卷尺周长换算法）或圆度仪测口沿，φ100 mm 件圆度误差 ≤0.5 mm，超差可用整形环轻校。每批抽 3%，数据贴随工单归档；连续三批数据同向偏移说明窝模磨损，应及时翻新凹砳并重新首检。
Run two outgoing checks on sunk work: (1) thinning—ultrasonic thickness at centre, transition and wall, ≤20% for tableware and 15% for pressure use; (2) roundness—π-tape (circumference method) or roundness tester at the rim, ≤0.5 mm on a φ100 mm piece, correctable with a light sizing ring. Sample 3% per batch and file the readings with the job card; three consecutive batches drifting the same way means the die is wearing—reface the block and re-run first-article inspection.