(3)如果轴是带有通孔的零件，则在钻通孔后，原中心孔消失。为了仍能使用

(3)如果轴是带有通孔的零件，则在钻通孔后，原中心孔消失。为了仍能使用中心孔定位，一般采用中心孔的锥塞或锥套芯轴。当轴孔锥度较大时(如铣床主轴)，可使用主轴。当主轴锥孔锥度较小时(如CA6140机床主轴)，可使用锥塞。必须注意的是，所使用的锥套芯轴和插塞应具有较高的精度，安装次数应尽量减少。锥塞和锥套芯轴上的中心孔不仅是制造时的定位基准，也是主轴外圆的精加工基准。如果是中小型批量生产，一般不更换工件后安装锥块。若外圆与锥孔需要相互反复加工，则在重新安装锥塞或套管芯棒时，中心孔必须对准或按外圆重新研磨。<br>从上面的分析可以看出,以下技术协议应考虑在选择定位基准在齿轮轴加工的过程:首先,钻中心孔的端面和外环作为粗基准,并准备粗糙的定位基准;粗车油缸为后续加工准备定位基准;然后,为了准备半完成加工的定位基准圆柱和整理加工圆柱,首先处理前后定位中心孔齿轮齿形加工也以中心孔为定位基准,这也体现了统一的参考原则,也充分体现了引用一致性原则。<br>定位基准包括粗基准和精基准。一般先确定精细基准，再确定粗基准。基地选择是工艺设计中最重要的任务之一。正确合理地选择基面可以保证加工质量，提高生产效率。否则在加工的过程中会有100多个问题，而且会导致大量的零件报废，导致生产无法正常进行。

(3)如果轴是带有通孔的零件，则在钻通孔后，原中心孔消失。 为了仍能使用中心孔定位，一般采用中心孔的锥塞或锥套芯轴。 当轴孔锥度较大时(如铣床主轴)，可使用主轴。 当主轴锥孔锥度较小时(如CA6140机床主轴)，可使用锥塞。 必须注意的是，所使用的锥套芯轴和插塞应具有较高的精度，安装次数应尽量减少。 锥塞和锥套芯轴上的中心孔不仅是制造时的定位基准，也是主轴外圆的精加工基准。 如果是中小型批量生产，一般不更换工件后安装锥块。 若外圆与锥孔需要相互反复加工，则在重新安装锥塞或套管芯棒时，中心孔必须对准或按外圆重新研磨。<br>从上面的分析可以看出,以下技术协议应考虑在选择定位基准在齿轮轴加工的过程:首先,钻中心孔的端面和外环作为粗基准,并准备粗糙的定位基准;粗车油缸为后续加工准备定位基准;然后,为了准备半完成加工的定位基准圆柱和整理加工圆柱,首先处理前后定位中心孔齿轮齿形加工也以中心孔为定位基准,这也体现了统一的参考原则,也充分体现了引用一致性原则。<br>定位基准包括粗基准和精基准。 一般先确定精细基准，再确定粗基准。 基地选择是工艺设计中最重要的任务之一。 正确合理地选择基面可以保证加工质量，提高生产效率。 否则在加工的过程中会有100多个问题，而且会导致大量的零件报废，导致生产无法正常进行。

(3) If the shaft is a part with a through hole, the original center hole disappears after the through hole is drilled. In order to still use the central hole positioning, the taper plug or the taper sleeve mandrel of the central hole is generally used. When the taper of shaft hole is large (such as milling machine spindle), the spindle can be used. When the taper of the taper hole of the spindle is small (such as the spindle of CA6140 machine tool), the taper plug can be used. It must be noted that the taper sleeve mandrel and plug used shall have high accuracy and the installation times shall be minimized. The central hole on the cone plug and the cone sleeve mandrel is not only the positioning datum during manufacturing, but also the finishing datum of the outer circle of the main shaft. If it is a small and medium-sized batch production, generally do not replace the workpiece after the installation of cone block. If the outer circle and the taper hole need to be processed repeatedly, the central hole must be aligned or reground according to the outer circle when reinstalling the taper plug or sleeve mandrel.<br>From the above analysis, it can be seen that the following technical agreement should consider the process of selecting the positioning datum for gear shaft machining: first, drill the end face and outer ring of the central hole as the coarse datum, and prepare the coarse positioning datum; rough turning cylinder prepare the positioning datum for the subsequent machining; then, prepare the positioning datum cylinder and finishing the machining cylinder for the semi-finished machining, First of all, before and after the processing, the tooth profile of the locating center hole is also based on the center hole, which also embodies the unified reference principle and fully embodies the principle of reference consistency.<br>Positioning datum includes coarse datum and fine datum. Generally, the fine datum is determined first, and then the coarse datum is determined. Base selection is one of the most important tasks in process design. The correct and reasonable selection of base surface can guarantee the processing quality and improve the production efficiency. Otherwise, there will be more than 100 problems in the process of processing, and a large number of parts will be scrapped, resulting in the normal production.<br>