Most of the typical thin-walled rotary workpieces are produced by turning. Under the concentrated action of the three claw clamping force, it is easy to have elastic deformation, and the deformation is the largest at 60 ° from the claw, protruding outward. Even if the hole cut or bored in the clamping state is a positive circle, once the claw is loosened, the elasticity of the part recovers, making the inner hole triangular, resulting in roundness error. In order to stabilize the product quality, it is often used as one of the most effective means to improve the manufacturability by transforming several hand conditions into uniform force or changing the force on the end face.
Rotary forming is a chip free processing technology. Its forming principle is: under the cold or hot state of plastic metal, the spindle on the lathe spindle rotates and the circular arc spinning wheel moves relatively along the spindle, exerting a certain pressure on the thin-walled blank, so that the blank produces plastic deformation along the shape of the spindle, and forms a hollow rotary workpiece.
Before spinning, first process a spindle according to the shape and size of the workpiece, install it on the lathe spindle, then squeeze the prepared circular blank on the end face of the spindle with the top cover and movable center, and correct it according to the excircle, then start the lathe to rotate the spindle and blank together, contact the spinning wheel with the workpiece blank under a certain pressure, drive the spinning wheel to rotate passively at high speed, and carry out longitudinal cutting according to the forming direction of the workpiece. The number and direction of cutting. Depending on the gradual deformation of the blank, it is generally not possible to form it by one-time spinning, otherwise wrinkles will appear and the workpiece will be scrapped. In the process of longitudinal walking to spinning, the tool must be gradually retreated horizontally. Each time the tool is spun, the length of longitudinal walking must be gradually increased and the length of horizontal retreating must be reduced. After spinning the blank for many times, the required workpiece can be formed.
The workpiece speed during spinning is (80-150) m/min, and the longitudinal feed rate is (0.15-0.5) mm / R. The best contact angle between spinning wheel and co construction is 30 °, and the arc radius is 2mm. When the wall thickness of spinning is more than 4mm, the blank shall be heated with oxyacetylene flame to soften it before spinning.