求翻译：本文从零件的分析和机械工艺设计两方面阐述了齿轮轴加工过程，特别是在工艺设计这方面，通过我们已经掌握和熟悉的理论知识，确定了机械加工工序、机械加工余量、工艺尺寸和毛坯尺寸，最后确定加工切削用量。为提高加工精度，特定选择了加工直齿轮轴外圆面时的夹具。是什么意思？

Explained from the parts and mechanical process design gear shaft process, especially in terms of process design, we have mastered and familiar theoretical knowledge to determine the machining process, machining allowances, process size and blank dimensions, and finally determine the amount of machi