GB/T 20957.2-2007 in English

《GB/T 20957.2-2007精密加工中心检验条件 第2部分：立式或带垂直主回转轴的万能主轴头机床 几何精度检验（垂直Z轴）》由TC22（全国金属切削机床标准化技术委员会）归口，主管部门为中国机械工业联合会。
本部分规定了精密立式加工中心的几何精度检验的要求及方法。

Scope

This part specifies the requirements and methods for the geometric accuracy inspection of precision vertical machining centers (ie: vertical Z axis). This part applies to precision vertical machining centers with essentially three numerically controlled axes, i.e. three linear axes (X, Y and Z) up to 2 000 mm, and also applies to additional movements of rams, quills or universal spindle heads , eg: axes of rotation (A´, B´ and C´). This part lists the inspection items for possible additional optional horizontal shafts and two additional universal spindle heads in the appendix: ——Appendix A: Optional horizontal shafts (inspection items AG1~AG6); ——Appendix B: Swing and swing Spindle head with one numerically controlled rotary axis (inspection items BG1~BG2); ——Appendix C: Rotary spindle head with two numerically controlled rotary axes perpendicular to each other (inspection items CG1~CG7). Precision vertical machining centers with a linear axis stroke greater than 2 000 mm can also be used as a reference.