How To Cut Precision Slender Shaft To Ensure Machining Quality
Due to the poor rigidity of the fine and slender shaft itself, the workpiece will be bent and vibrated under the action of cutting force, self-weight and centrifugal force during turning during the turning process, which seriously affects its cylindricity and surface roughness. During the cutting process, the workpiece will be bent and deformed due to thermal elongation; turning is difficult, and in severe cases, the workpiece will be stuck between the tops.
Therefore, turning the fine and slender shaft is a difficult processing technology. Although it is more difficult to turn fine and slender shafts, it also has certain regularity. First, three key technologies, such as the use of the center frame and the tool rest, the treatment of the thermal deformation and elongation of the workpiece, and the reasonable selection of the geometry of the turning tool, are used. Problem solved easily.
When turning fine slender shafts, a steady rest can be used to increase the rigidity of the workpiece. When the workpiece can be turned in sections, the steady rest is supported in the middle of the workpiece. In this way, the L/d value is reduced by half, and the rigidity during turning of fine and slender shafts can be increased several times. Before the workpiece is mounted on the center frame, a groove for supporting the support jaws of the center frame must be turned in the middle of the blank. The surface roughness and cylindricity errors should be small, otherwise the accuracy of the workpiece will be affected.
During turning, lubricating oil should always be added to the place where the support claws of the center frame touch the workpiece. In order to keep the support claw and the workpiece in good contact, a layer of abrasive cloth or abrasive can also be added between the center frame support claw and the workpiece for grinding and cohesion. You can add touch on the outer surface of the transition sleeve. The two ends of the transition sleeve are equipped with four screws, and the blank workpiece is clamped by these screws, and the axis of the outer circle of the sleeve is adjusted to coincide with the axis of rotation of the main shaft, and the turning can be done.
When turning fine and slender shafts, the workpiece is gradually elongated and deformed with the increase of temperature due to the influence of cutting heat. The thermal deformation elongation of the elongated shaft is large. Because one end of the workpiece is clamped and one end is held up, the workpiece cannot be stretched, so it can only bend itself. Once the slender shaft is bent, turning is difficult.
Therefore, using the elastic rotating top to process the fine and slender shaft can better compensate the thermal deformation and elongation of the workpiece, the workpiece is not easy to bend, and the turning can be carried out smoothly. Whether it is low-speed cutting or high-speed cutting, in order to reduce the thermal deformation caused by the temperature rise of the workpiece, it is necessary to add cutting fluid for sufficient cooling. The use of cutting fluid can also avoid pulling the workpiece with the tool rest support claw, and improve the service life of the tool and the processing quality of the workpiece.