Spinning machining clamping method and device for large-diameter thin-wall cylindrical part

Abstract

The invention discloses a spinning machining clamping method and device for a large-diameter thin-wall cylindrical part. Comprising a box body and a barrel-shaped clamping mechanism, and the barrel-shaped clamping mechanism is arranged in the box body; the barrel-shaped clamping mechanism is used for clamping a barrel-shaped blank in the spinning process; the barrel-shaped clamping mechanism comprises an outer barrel and an inner barrel which are arranged together in a sleeved mode. The inner cylinder comprises a rear cylinder and a clamping cylinder arranged at the opening part of the rear cylinder; the rear cylinder and the clamping cylinder are located on the same axis. And when the rear cylinder moves towards the clamping cylinder, the opening part of the clamping cylinder shrinks and clamps the cylindrical blank in the clamping cylinder. According to the clamping device, it can be guaranteed that the blank can be firmly clamped in the spinning process, meanwhile, it is guaranteed that one end of the blank can be smoothly disengaged after spinning is completed, the other end of the blank can be subjected to spinning machining after turning around and clamping, and therefore spinning of the two ends of the blank is achieved.

Description

Technical Field

[0001] The invention relates to the field of diameter reduction spinning, and in particular to a spinning processing clamping method and device for a large-diameter thin-walled cylindrical part. Background Art

[0002] Gas cylinder parts and engine housings and missile housings in the aerospace field can be manufactured by spinning the cylindrical parts. Compared with the traditional forming process, spinning has great advantages in the overall forming of parts, which is conducive to reducing the welding between parts and improving the overall strength and appearance quality of the parts. At the same time, spinning is a point processing, the forming force is small and it will not interrupt the internal flow line of the metal material, so the product with better performance can be obtained.

[0003] However, when spinning large-diameter thin-walled cylindrical parts, the clamping of the blank becomes a major problem due to the large diameter and small wall thickness of such blanks. At the same time, when the clamping force of the clamping device is too large, the clamping device will cause plastic deformation of the workpiece or leave irreversible appearance wear on the surface of the workpiece. When the clamping force is too small, the blank will be dragged out axially by the spinning wheel or rotate tangentially, making it impossible to continue spinning. At the same time, most existing clamping devices use the method of fitting the blank on the core mold and clamping the blank by the chuck. This type of tooling is not suitable for blanks that need to be processed at both ends.

[0004] Therefore, designing a spinning clamping device with moderate clamping force and allowing processing at both ends of the blank is of great significance for forming parts with fewer welds and better performance. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings and deficiencies of the above-mentioned prior art and provide a method and device for clamping a large-diameter thin-walled cylindrical part during spinning. The clamping device can ensure that the blank can be firmly clamped during the spinning process, and at the same time ensure that one end of the blank can be smoothly removed after the spinning is completed. After the blank is turned around and clamped, the other end can be spun, thereby realizing the spinning of both ends of the blank.

[0006] The present invention is achieved through the following technical solutions: A large-diameter thin-walled cylindrical part spinning processing clamping device, comprising a box body 1 and a cylindrical clamping mechanism 2, wherein the cylindrical clamping mechanism 2 is placed inside the box body 1; the cylindrical clamping mechanism 2 is used to clamp the cylindrical blank during the spinning process; The barrel-type clamping mechanism 2 comprises an outer barrel 3 and an inner barrel which are sleeved together; The inner cylinder can move axially relative to the outer cylinder 3; An inner tube end cap 4 is provided on one side of the inner tube, and an outer tube end cap 5 is provided on one end of the outer tube 3; the other ends of the inner tube and the outer tube 3 are both open; The inner cylinder includes a rear cylinder 6 and a clamping cylinder 7 at the mouth of the rear cylinder 6; the rear cylinder 6 and the clamping cylinder 7 are located on the same axis; both ends of the clamping cylinder 7 are open; When the rear cylinder 6 moves toward the clamping cylinder 7, the mouth of the clamping cylinder 7 contracts and clamps the cylindrical blank therein.

[0007] The contraction action of the mouth of the clamping tube 7 is achieved with the assistance of the inclined surface, specifically: the end of the clamping tube 7 that contacts the rear tube 6 is matched with the inclined surface; the clamping tube 7 is matched with the inclined sleeve 8 arranged at the mouth of the outer tube 3; the wall surfaces of the openings at both ends of the clamping tube 7 have a plurality of cuts along the axial direction; when the rear tube 6 pushes the clamping tube 7 forward, the diameters of the two end portions of the clamping tube 7 gradually become smaller under the extrusion action of the inclined surface, and elastically shrink toward the center to clamp the cylindrical blank therein.

[0008] The rear cylinder 6 is provided with a hook-shaped member 9; a right-angled groove 10 is provided in the middle of the clamping cylinder 7, and the hook of the hook-shaped member 9 is located in the right-angled groove 10, and the hook can move in the right-angled groove 10; When the rear tube 6 moves toward the outer tube end cover 5, the hook-shaped member 9 hooks the clamping tube 7 and moves together, and the extrusion torque between the clamping tube 7 and the cylindrical blank is released. At this time, the diameter of the openings at both ends of the clamping tube 7 gradually increases after leaving the inclined surface, thereby separating the clamping tube 7 from the cylindrical blank.

[0009] 4. According to claim 3, the clamping device that allows the spinning processing of both ends of large-diameter thin-walled cylindrical parts is characterized in that a keyway 11 is provided on the outer peripheral wall of the rear cylinder 6, and the keyway 11 is provided with a guide key 12; a guide groove 13 is opened on the outer cylinder 3 corresponding to the guide key 12; the guide key 12 can move within the trajectory of the guide groove 13; the length direction of the guide groove 13 is parallel to the axis of the outer cylinder 3.

[0010] A bearing base 14 is provided on one side of the box body 1, a hollow shaft 15 is installed on the bearing base 14, and a push-pull shaft 16 is provided inside the hollow shaft 15; The inner end of the hollow shaft 15 is connected to the outer tube end cover 5 of the outer tube 3, and the outer end of the hollow shaft 15 is connected to the pulley 17, and the pulley 17 can drive the hollow shaft 15 to rotate; The outer end of the push-pull shaft 16 is connected to the rotary cylinder 18, and the inner end of the push-pull shaft 16 passes through the outer tube end cover 5 and is connected to the rear tube 6 end cover; the rotary cylinder 18 can drive the push-pull shaft 16 to make a linear reciprocating motion, thereby driving the rear tube 6 of the inner tube to move linearly back and forth along the axis.

[0011] The opening of the outer cylinder 3 is fixed to the box body 1 through a shaft sleeve 19 .

[0012] The slope is 15° to 45°.

[0013] The bevel jacket 8 is threadedly connected to the outer tube 3 .

[0014] The clamping cylinder 7 is a spring steel clamping cylinder 7 .

[0015] A method for clamping a cylindrical part during a spinning process comprises the following steps: When the cylindrical blank is ready for spinning, first insert one end of the cylindrical blank into the clamping cylinder 7, start the rotary cylinder 18 and drive the push-pull shaft 16 to move forward, so that the mouth of the clamping cylinder 7 contracts, specifically: the end of the clamping cylinder 7 that contacts the rear cylinder 6 is matched with the inclined surface; the clamping cylinder 7 cooperates with the inclined surface jacket 8 set at the mouth of the outer cylinder 3; the wall surface of the opening at both ends of the clamping cylinder 7 has a plurality of cuts along the axial direction; when the rear cylinder 6 pushes the clamping cylinder 7 forward, the diameter of the two end portions of the clamping cylinder 7 gradually decreases under the extrusion of the inclined surface, and elastically contracts toward the center to clamp the cylindrical blank therein; after the cylindrical blank is clamped, the pulley 17 starts to rotate, and under the action of the guide key 12, the outer cylinder 3 and the inner cylinder rotate synchronously, thereby driving the cylindrical blank to rotate and completing the spinning process; When one end of the cylindrical blank completes the spinning operation, the rotary cylinder 18 drives the push-pull shaft 16 to move backward, and the rear cylinder 6 moves backward under the pull of the push-pull shaft 16. Since the rear cylinder 6 is equipped with a hook-shaped part 9, it hooks the right-angle groove 10 in the middle of the clamping cylinder 7, and pulls the rear cylinder 6 toward the outer cylinder end cover 5. At the same time, the hook-shaped part 9 hooks the clamping cylinder 7 and moves together, so that the extrusion torque between the clamping cylinder 7 and the cylindrical blank is released. At this time, the diameter of the openings at both ends of the clamping cylinder 7 after leaving the inclined surface gradually increases, so that the clamping cylinder 7 is separated from the cylindrical blank, and then the other end of the cylindrical blank is replaced for clamping, and the spinning operation is completed.

[0016] Compared with the prior art, the present invention has the following advantages and effects: When the cylindrical blank is ready for spinning, first insert one end of the cylindrical blank into the clamping cylinder 7, start the rotary cylinder 18 and drive the push-pull shaft 16 to move forward, so that the mouth of the clamping cylinder 7 contracts, specifically: the end of the clamping cylinder 7 that contacts the rear cylinder 6 is matched with the inclined surface; the clamping cylinder 7 cooperates with the inclined surface jacket 8 set at the mouth of the outer cylinder 3; the wall surface of the opening at both ends of the clamping cylinder 7 has a plurality of cuts along the axial direction; when the rear cylinder 6 pushes the clamping cylinder 7 forward, the diameter of the two end portions of the clamping cylinder 7 gradually decreases under the extrusion of the inclined surface, and elastically contracts toward the center to clamp the cylindrical blank therein; after the cylindrical blank is clamped, the pulley 17 starts to rotate, and under the action of the guide key 12, the outer cylinder 3 and the inner cylinder rotate synchronously, thereby driving the cylindrical blank to rotate and completing the spinning process; When one end of the cylindrical blank completes the spinning operation, the rotary cylinder 18 drives the push-pull shaft 16 to move backward, and the rear cylinder 6 moves backward under the pull of the push-pull shaft 16. Since the rear cylinder 6 is equipped with a hook-shaped part 9, it hooks the right-angle groove 10 in the middle of the clamping cylinder 7, and pulls the rear cylinder 6 toward the outer cylinder end cover 5. At the same time, the hook-shaped part 9 hooks the clamping cylinder 7 and moves together, so that the extrusion torque between the clamping cylinder 7 and the cylindrical blank is released. At this time, the diameter of the openings at both ends of the clamping cylinder 7 after leaving the inclined surface gradually increases, so that the clamping cylinder 7 is separated from the cylindrical blank, and then the other end of the cylindrical blank is replaced for clamping, and the spinning operation is completed.

[0017] In summary, the present invention clamps the middle part of the cylindrical blank through the clamping tube, and can perform spinning on both ends of the blank. The present invention can ensure that the blank can be firmly clamped during the spinning process, and ensure that one end of the cylindrical blank can be smoothly removed after spinning. After turning around and clamping, the other end of the blank can be spun, thereby realizing spinning on both ends of the blank.

[0018] By adopting the clamping device of the present invention, the two ends of the cylindrical part are spun to avoid welding between two or more parts, which is beneficial to reducing the weld seam and thus improving the overall strength and appearance quality of the part. At the same time, the present invention adopts a motor with relatively low power for driving, and the working state is relatively stable.

[0019] The invention also has the advantages of low production cost, high rigidity, easy promotion and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a large-diameter thin-walled cylindrical part blank after spinning processing.

[0021] Figure 2 It is a schematic diagram of the structure of the spinning processing clamping device of the present invention.

[0022] Figure 3 It is a schematic diagram of the rear-mounted tube structure of the present invention.

[0023] Figure 4 It is a schematic diagram of the outer cylinder structure of the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with specific embodiments.

[0025] like Figure 1-4 As shown, the present invention discloses a large-diameter thin-walled cylindrical part spinning processing clamping device, comprising a box body 1 and a cylindrical clamping mechanism 2, wherein the cylindrical clamping mechanism 2 is placed inside the box body 1; the cylindrical clamping mechanism 2 is used to clamp the cylindrical blank during the spinning process; The barrel-type clamping mechanism 2 comprises an outer barrel 3 and an inner barrel which are sleeved together; The inner cylinder can move axially relative to the outer cylinder 3; An inner tube end cap 4 is provided on one side of the inner tube, and an outer tube end cap 5 is provided on one end of the outer tube 3; the other ends of the inner tube and the outer tube 3 are both open; The inner cylinder includes a rear cylinder 6 and a clamping cylinder 7 at the mouth of the rear cylinder 6; the rear cylinder 6 and the clamping cylinder 7 are located on the same axis; both ends of the clamping cylinder 7 are open; When the rear cylinder 6 moves toward the clamping cylinder 7, the mouth of the clamping cylinder 7 contracts and clamps the cylindrical blank therein.

[0026] The contraction action of the mouth of the clamping tube 7 is achieved with the assistance of the inclined surface, specifically: the end of the clamping tube 7 that contacts the rear tube 6 is matched with the inclined surface; the clamping tube 7 is matched with the inclined sleeve 8 arranged at the mouth of the outer tube 3; the wall surfaces of the openings at both ends of the clamping tube 7 have a plurality of cuts along the axial direction; when the rear tube 6 pushes the clamping tube 7 forward, the diameters of the two end portions of the clamping tube 7 gradually become smaller under the extrusion action of the inclined surface, and elastically shrink toward the center to clamp the cylindrical blank therein.

[0027] The rear cylinder 6 is provided with a hook-shaped member 9; a right-angled groove 10 is provided in the middle of the clamping cylinder 7, and the hook of the hook-shaped member 9 is located in the right-angled groove 10, and the hook can move in the right-angled groove 10; When the rear tube 6 moves toward the outer tube end cover 5, the hook-shaped member 9 hooks the clamping tube 7 and moves together, and the extrusion torque between the clamping tube 7 and the cylindrical blank is released. At this time, the diameter of the openings at both ends of the clamping tube 7 gradually increases after leaving the inclined surface, thereby separating the clamping tube 7 from the cylindrical blank.

[0028] 4. According to claim 3, the clamping device that allows the spinning processing of both ends of large-diameter thin-walled cylindrical parts is characterized in that a keyway 11 is provided on the outer peripheral wall of the rear cylinder 6, and the keyway 11 is provided with a guide key 12; a guide groove 13 is opened on the outer cylinder 3 corresponding to the guide key 12; the guide key 12 can move within the trajectory of the guide groove 13; the length direction of the guide groove 13 is parallel to the axis of the outer cylinder 3.

[0029] A bearing base 14 is provided on one side of the box body 1, a hollow shaft 15 is installed on the bearing base 14, and a push-pull shaft 16 is provided inside the hollow shaft 15; The inner end of the hollow shaft 15 is connected to the outer tube end cover 5 of the outer tube 3, and the outer end of the hollow shaft 15 is connected to the pulley 17, and the pulley 17 can drive the hollow shaft 15 to rotate; The outer end of the push-pull shaft 16 is connected to the rotary cylinder 18, and the inner end of the push-pull shaft 16 passes through the outer tube end cover 5 and is connected to the rear tube 6 end cover; the rotary cylinder 18 can drive the push-pull shaft 16 to make a linear reciprocating motion, thereby driving the rear tube 6 of the inner tube to move linearly back and forth along the axis.

[0030] The opening of the outer cylinder 3 is fixed to the box body 1 through a shaft sleeve 19 .

[0031] The slope is 15° to 45°.

[0032] The bevel jacket 8 is threadedly connected to the outer tube 3 .

[0033] The clamping cylinder 7 is a spring steel clamping cylinder 7 .

[0034] The inner wall surface of the clamping cylinder 7 is a mesh groove surface, and the grooves of the mesh grooves have inclined surfaces with different angles.

[0035] Figure 1 The dotted line is a schematic diagram of the structure of a large-diameter thin-walled cylindrical blank before spinning. The diameter of this cylindrical blank is 400mm and the wall thickness is 1.5mm. It is characterized by a large diameter and a small wall thickness, and is not easy to clamp during the spinning process. At the same time, both ends of the cylindrical blank need to be spun, so the blank must be clamped near the middle of the blank; Figure 1 The solid line is a schematic diagram of the structure of the blank after spinning at both ends. After spinning, the total length of the tube blank is reduced.

[0036] A method for clamping a cylindrical part during a spinning process comprises the following steps: When the cylindrical blank is ready for spinning, first insert one end of the cylindrical blank into the clamping cylinder 7, start the rotary cylinder 18 and drive the push-pull shaft 16 to move forward, so that the mouth of the clamping cylinder 7 contracts, specifically: the end of the clamping cylinder 7 that contacts the rear cylinder 6 is matched with the inclined surface; the clamping cylinder 7 cooperates with the inclined surface jacket 8 set at the mouth of the outer cylinder 3; the wall surface of the opening at both ends of the clamping cylinder 7 has a plurality of cuts along the axial direction; when the rear cylinder 6 pushes the clamping cylinder 7 forward, the diameter of the two end portions of the clamping cylinder 7 gradually decreases under the extrusion of the inclined surface, and elastically contracts toward the center to clamp the cylindrical blank therein; after the cylindrical blank is clamped, the pulley 17 starts to rotate, and under the action of the guide key 12, the outer cylinder 3 and the inner cylinder rotate synchronously, thereby driving the cylindrical blank to rotate and completing the spinning process; When one end of the cylindrical blank completes the spinning operation, the rotary cylinder 18 drives the push-pull shaft 16 to move backward, and the rear cylinder 6 moves backward under the pull of the push-pull shaft 16. Since the rear cylinder 6 is equipped with a hook-shaped part 9, it hooks the right-angle groove 10 in the middle of the clamping cylinder 7, and pulls the rear cylinder 6 toward the outer cylinder end cover 5. At the same time, the hook-shaped part 9 hooks the clamping cylinder 7 and moves together, so that the extrusion torque between the clamping cylinder 7 and the cylindrical blank is released. At this time, the diameter of the openings at both ends of the clamping cylinder 7 after leaving the inclined surface gradually increases, so that the clamping cylinder 7 is separated from the cylindrical blank, and then the other end of the cylindrical blank is replaced for clamping, and the spinning operation is completed.

[0037] As described above, the present invention can be implemented well.

[0038] The implementation methods of the present invention are not limited to the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A clamping device for spinning of a large-diameter thin-walled cylindrical part, comprising a box body (1) and a cylindrical clamping mechanism (2), wherein the cylindrical clamping mechanism (2) is disposed inside the box body (1); the cylindrical clamping mechanism (2) is used to clamp the cylindrical blank during the spinning process; and is characterized in that: The cylindrical clamping mechanism (2) comprises an outer cylinder (3) and an inner cylinder which are sleeved together; The inner cylinder is capable of axial movement relative to the outer cylinder (3); An inner cylinder end cover (4) is provided on one side of the inner cylinder, and an outer cylinder end cover (5) is provided on one end of the outer cylinder (3); the other ends of the inner cylinder and the outer cylinder (3) are both open; The inner cylinder comprises a rear cylinder (6) and a clamping cylinder (7) at the mouth of the rear cylinder (6); the rear cylinder (6) and the clamping cylinder (7) are located on the same axis; both ends of the clamping cylinder (7) are open; When the rear cylinder (6) moves toward the clamping cylinder (7), the mouth of the clamping cylinder (7) contracts and clamps the cylindrical blank therein.

2. The large-diameter thin-walled cylindrical parts spinning processing clamping device according to claim 1 is characterized in that: The contraction action of the mouth of the clamping tube (7) is achieved with the assistance of the inclined surface, specifically: the end of the clamping tube (7) that contacts the rear tube (6) is matched with the inclined surface; the clamping tube (7) is matched with the inclined surface jacket (8) arranged at the mouth of the outer tube (3); the wall surface of the openings at both ends of the clamping tube (7) has a plurality of cuts along the axial direction; when the rear tube (6) pushes the clamping tube (7), the diameters of the two end portions of the clamping tube (7) gradually decrease under the extrusion action of the inclined surface, and elastically contract toward the center to clamp the cylindrical blank therein.

3. The large-diameter thin-walled cylindrical parts spinning processing clamping device according to claim 1 is characterized in that: The rear cylinder (6) is provided with a hook-shaped member (9); a right-angled groove (10) is provided in the middle of the clamping cylinder (7), and a hook of the hook-shaped member (9) is located in the right-angled groove (10), and the hook can move in the right-angled groove (10); When the rear cylinder (6) moves toward the outer cylinder end cover (5), the hook-shaped member (9) hooks the clamping cylinder (7) and moves together, and the extrusion torque between the clamping cylinder (7) and the cylindrical blank is released. At this time, the diameters of the openings at both ends of the clamping cylinder (7) gradually increase after they are separated from the inclined surface, thereby separating the clamping cylinder (7) from the cylindrical blank.

4. The large-diameter thin-walled cylindrical parts spinning processing clamping device according to claim 3 is characterized in that: A keyway (11) is provided on the outer peripheral wall of the rear cylinder (6), and a guide key (12) is provided in the keyway (11); a guide groove (13) is provided on the outer cylinder (3) corresponding to the guide key (12); the guide key (12) can move within the track of the guide groove (13); and the length direction of the guide groove (13) is parallel to the axis of the outer cylinder (3).

5. The large-diameter thin-walled cylindrical parts spinning processing clamping device according to claim 3 is characterized in that: A bearing base (14) is provided on one side of the box body (1), a hollow shaft (15) is mounted on the bearing base (14), and a push-pull shaft (16) is provided inside the hollow shaft (15); The inner end of the hollow shaft (15) is connected to the outer cylinder end cover (5) of the outer cylinder (3), and the outer end of the hollow shaft (15) is connected to the pulley (17), and the pulley (17) can drive the hollow shaft (15) to rotate; The outer end of the push-pull shaft (16) is connected to the rotary cylinder (18), and the inner end of the push-pull shaft (16) passes through the end cover (5) of the outer cylinder and is connected to the end cover of the rear cylinder (6); the rotary cylinder (18) can drive the push-pull shaft (16) to perform linear reciprocating motion, thereby driving the rear cylinder (6) of the inner cylinder to perform linear reciprocating motion along the axis.

6. The large-diameter thin-walled cylindrical parts spinning processing clamping device according to claim 1 is characterized in that: The opening of the outer cylinder (3) is fixed to the box body (1) via a shaft sleeve (19).

7. The large-diameter thin-walled cylindrical parts spinning processing clamping device according to claim 2 is characterized in that: The slope is 15° to 45°.

8. The large-diameter thin-walled cylindrical parts spinning processing clamping device according to claim 2 is characterized in that: The inclined jacket (8) is threadedly connected to the outer cylinder (3).

9. The large-diameter thin-walled cylindrical part spinning processing clamping device according to claim 2 is characterized in that: The clamping cylinder (7) is a spring steel clamping cylinder (7).

10. A method for clamping a cylindrical part during spinning, characterized in that The method is implemented by using the clamping device that allows spinning processing at both ends of a large-diameter thin-walled cylindrical part as described in any one of claims 1 to 8, and specifically comprises the following steps: When the cylindrical blank is ready for spinning, one end of the cylindrical blank is first inserted into the clamping cylinder (7), the rotary cylinder (18) is started and the push-pull shaft (16) is driven to move forward, so that the mouth of the clamping cylinder (7) contracts. Specifically, the end of the clamping cylinder (7) that contacts the rear cylinder (6) is matched with an inclined surface; the clamping cylinder (7) is matched with an inclined surface jacket (8) arranged at the mouth of the outer cylinder (3); the wall surface of the openings at both ends of the clamping cylinder (7) has a plurality of cuts along the axial direction; when the rear cylinder (6) pushes the clamping cylinder (7) forward, the diameters of the two end portions of the clamping cylinder (7) gradually decrease under the extrusion of the inclined surface, and elastically contract toward the center to clamp the cylindrical blank therein; after the cylindrical blank is clamped, the pulley (17) starts to rotate, and under the action of the guide key (12), the outer cylinder (3) and the inner cylinder rotate synchronously, thereby driving the cylindrical blank to rotate and completing the spinning process; When the spinning operation is completed at one end of the cylindrical blank, the rotary cylinder (18) drives the push-pull shaft (16) to move backward, and the rear cylinder (6) moves backward under the pull of the push-pull shaft (16). Since the rear cylinder (6) is equipped with a hook-shaped member (9), it hooks the right-angled groove (10) in the middle of the clamping cylinder (7), pulls the rear cylinder (6) toward the outer cylinder end cover (5), and at the same time, the hook-shaped member (9) hooks the clamping cylinder (7) and moves together, so that the extrusion torque between the clamping cylinder (7) and the cylindrical blank is released. At this time, the diameters of the two end openings of the clamping cylinder (7) gradually increase after they are separated from the inclined surface, so that the clamping cylinder (7) is separated from the cylindrical blank, and then the other end of the cylindrical blank is replaced for clamping, and the spinning operation is completed.

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