The paper presents reasons and preventing measures for crack of big blank cap happened in roughing tool, which can give some reference for such machine production in future.

• 本文针对近期生产的选矿厂大端盖,在粗车加工时发现的裂纹缺陷进行分析,查找原因,制定预防措施,保证了后期制作此类铸件的质量