Why do you want to use the center frame and the tool holder when machining the slender shaft?
Because, when processing the slender shaft, the process system rigidity problems, mainly for the slender shaft rigidity is low, the cutting force (radial force) under the action of bending deformation (elastic deformation), car axle, a middle drum. The center frame or the tool holder is used to counteract the radial cutting force and increase the rigidity of the slender shaft.
In order to prevent the workpiece from bending deformation due to the radial cutting force, the central frame or the tool holder is used as the auxiliary support to increase the rigidity of the workpiece.
When machining slender shafts, use the center frame and the tool holder for the following reasons:First, the use of the central support of the vehicle shaft1, the central frame is directly supported in the middle of the workpiece when the workpiece can be segmented, the center of the support in the middle of the workpiece, so that the support, L/d value reduced by half, slender shaft turning rigidity can be increased several times. Before the work piece is installed on the center frame, it must be in the middle part of the blank to produce a part of the support of the central support of the groove, the surface roughness and cylindricity error is small, otherwise it will affect the accuracy of the workpiece.Two, the use of the tool holder with the support of the fine axisWith the tool holder fixed on the bed saddle, there are generally two supporting claws, with the tool holder can follow the movement of the tool to offset radial cutting can increase the stiffness of the workpiece, reduce deformation. So as to improve the shape precision and reduce the surface roughness.According to the design principle of the tool holder, only two supporting claws can be used, because the cutting resistance of the lathe tool to the workpiece is F`r, the workpiece is stuck on the two supporting claws of the tool rest. But in actual use, the workpiece itself has a downward gravity, and bending workpiece inevitably therefore, when turning the workpiece, often due to centrifugal force instantaneous left supporting claw, a supporting claw contact vibration. If the three supporting claws are used to support the workpiece, the workpiece is supported by a lathe tool, so that the upper and the lower parts of the workpiece can not move, and the turning is stable, and the vibration is not easy to generate. Therefore, when the car is fine to find a very critical problem is to use the shaft with three claws.
