零件是组成机械和机器的不可分拆的单个制件，其制造过程一般不需要装配工序。如轴套、轴瓦、螺母、曲轴、叶片、齿轮、凸轮、连杆体、连杆头等。零件是机械制造过程中的基本单元-Parts are inextricably single composition machinery and machine parts, its manufacturing process is generally no assembly step is required. Such as bushings, bearings,