Method for controlling vibration during machining of cylindrical thin-walled parts

Abstract

The present invention relates to the field of precision machinery manufacturing technology, and particularly to a method for controlling tremors during the machining of cylindrical thin-walled parts. The machining process includes milling the side surface and turning the end face and outer circle. The tremors include radial tremors, axial tremors, and eccentric tremors. The method for controlling tremors includes: arranging a guard plate around the circumferential side surface of the milling die, and tightly fitting and fixing the guard plate to the side surface, so that the side surface is radially fixed to the milling die through the guard plate; arranging an external support structure and an internal support structure on the turning die, supporting the outer side surface of the hollow annular end face with the external support structure, and supporting the inner side surface of the hollow annular end face with the internal support structure, so as to control the radial tremors of the side surface during the milling process and the axial tremors of the hollow annular end face during the turning process. The present invention adopts special vertical lathe machining dies and milling dies, improves the machining accuracy, and reduces the tremors and deformations caused in the two directions of axial and radial and by eccentricity.

Description

Technical Field

[0001] The invention relates to the technical field of precision machinery manufacturing, and in particular to a method for controlling vibration during the machining of a cylindrical thin-walled part. Background Art

[0002] Large cylindrical magnesium alloy thin-walled parts are widely needed in the aviation field. Since they cannot be welded and the dimensions of the casting process are difficult to meet the precision requirements, the production of lightweight alloy hollow parts is currently mainly based on machine tool processing (turning, milling, etc.).

[0003] For high-precision large-scale cylindrical magnesium alloy thin-walled parts, a common processing method is to machine the large-scale magnesium alloy blanks formed by casting to obtain more accurate internal structure and size; since thin-walled parts are easily deformed by clamping from the outer wall, the fixed mold for thin-walled parts machining often adopts the method of supporting and fixing inside the part cavity. On the one hand, such mold fixation occupies the inner cavity space of the part, especially affecting the fine processing of the inner wall of the part, such as milling; on the other hand, thin-walled parts are prone to vibration during radial processing of the parts. The defects of the existing molds determine that they can only be fixed at one end of the axial direction of the part to be processed, and the other end is left with an open end for the lathe spindle to enter and exit, resulting in the lack of mold fixation at the open end, which leads to particularly serious vibration, seriously affecting the processing accuracy of the equipment; at the same time, for large magnesium alloy thin-walled parts, due to the reduction of radial section curvature, the vibration of the side wall of the part is more serious. At present, the market is in urgent need of a method for controlling vibration during the processing of cylindrical thin-walled parts to solve the problem of fixing and reducing the processing accuracy due to vibration during the processing of large cylindrical thin-walled parts. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a method for controlling vibration during the processing of cylindrical thin-walled parts, so as to solve at least one of the problems in the prior art, such as poor mold fixing stability and easy vibration.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] The present invention provides a method for controlling vibration during the processing of a cylindrical thin-walled part, wherein the processing includes milling of the side surface of the cylindrical thin-walled part and lathing of the end surface and the outer circle of the cylindrical thin-walled part, and the vibration includes radial vibration and axial vibration; the method for controlling vibration includes:

[0007] A guard plate is arranged around the circumferential side of the milling mold, and the guard plate is tightly fitted and fixed to the side, so that the side is radially fixed to the milling mold through the guard plate, so as to control the radial vibration of the side during the milling process;

[0008] An external support structure and an internal support structure are arranged on the turning mold, the external support structure is pressed to support the outer side surface of the hollow annular end surface, and the internal support structure is pressed to support the inner side surface of the hollow annular end surface, so as to control the axial vibration of the hollow annular end surface during the turning process.

[0009] Preferably, the vibration also includes eccentric vibration, and the eccentric vibration control method includes: correcting the axis of the thin-walled part blank based on the fitting image of the thin-walled part blank and the theoretical image of the thin-walled part blank, performing vertical lathe processing based on the corrected axis, obtaining a thin-walled part blank with uniform wall thickness, and realizing the control of eccentric vibration during the processing.

[0010] Preferably, the method for acquiring the fitting image of the thin-walled workpiece blank includes: using sensors densely distributed on the inner and outer surfaces of the thin-walled workpiece blank as data sampling points, using laser scanning to acquire the coordinates of the sensors in the spatial coordinate system, and fitting a three-dimensional image of the thin-walled workpiece blank according to the spatial coordinate information of the sensors.

[0011] Preferably, the step of obtaining a thin-walled blank with uniform wall thickness comprises:

[0012] S301: connecting the centers of the positioning blocks symmetrical with respect to the axis center as the reference positioning line of the hollow annular end face, obtaining a fitting image of the thin-walled blank based on laser scanning fitting imaging, and correcting the reference positioning line based on the fitting image of the thin-walled blank; the thin-walled blank has a side surface, an unobstructed free end surface and a hollow annular end surface; the inner surface of the side surface is provided with at least two positioning blocks symmetrical with respect to the axis center;

[0013] S302: performing vertical lathe processing on both end faces and the outer circle of the side of the thin-walled blank after the calibration of the reference positioning line, so as to obtain a thin-walled blank with uniform wall thickness.

[0014] Preferably, the step of correcting the axis of the thin-walled workpiece blank based on the fitting image of the thin-walled workpiece blank comprises:

[0015] S3011: Using laser scanning fitting imaging software, the fitting image of the part blank and the axis line of the theoretical image of the thin-walled part blank are overlapped and combined, the thickness of each area of ​​the radial section of the part blank is compared, the deviation is automatically obtained and color-coded according to the deviation size;

[0016] S3012: If the radial section deviations are less than or equal to the first threshold δ 1 , without any adjustment, the reference positioning line is calibrated;

[0017] If the radial section deviation is greater than the first threshold δ 1 , adjust the position of the axis of the theoretical image of the thin-walled blank until the deviation of each radial section is less than or equal to the first threshold δ 1, record the position change value △(x, y, z) of the axis centerline in the spatial coordinate system;

[0018] S3013: Construct a spatial coordinate system that is the same as the fitting image of the part blank and the theoretical image of the thin-walled part blank, and change the axis of the part blank according to △(x, y, z) in the coordinate system to obtain the axis coordinates of the corrected part blank.

[0019] Preferably, the vibration control method also includes the control of axial vibration during milling: radial vibration fixes the milling mold to the two end surfaces of the cylindrical thin-walled part at the same time, so that the two end surfaces of the thin-walled part are axially fixed to the milling mold, and the control of axial vibration during milling is achieved.

[0020] Preferably, the milling mold has a first pressing plate pressed and connected to one end thereof, and a first bottom fixing piece pressed and connected to the other end thereof; the milling mold also has a first pull rod connecting the first pressing plate and the first bottom fixing piece.

[0021] Preferably, the first pull rods are arranged in plurality along the circumferential direction of the side surface, and a milling mold is provided with a guard plate on the side surface of the thin-walled part to limit the radial vibration of the thin-walled part; the guard plate circumferentially surrounds the side surface and is provided with a first through hole arranged axially; the first through hole corresponds one-to-one to the first pull rod; the first pull rod passes through the first through hole to radially fix the guard plate; at the same time, the guard plate and the side surface are circumferentially fitted together to generate a sufficiently large static friction force to achieve axial fixation of the guard plate; the guard plate is circumferentially fitted to the side surface to limit the radial deformation or vibration of the thin-walled part toward the outside.

[0022] Preferably, the vibration control method also includes controlling the overall axial vibration of the thin-walled part during turning: the turning mold is fixedly connected to the two end surfaces of the cylindrical thin-walled part at the same time, so that the two end surfaces of the thin-walled part are axially fixed to the turning mold, and the overall axial vibration of the thin-walled part during turning is controlled.

[0023] Preferably, one end of the turning mold is provided with a second pressure plate press-connected thereto, and the other end is provided with a second bottom fixing piece press-connected thereto, and the second pressure plate is press-connected to the hollow annular end face; one end of the external support structure is fixedly connected to the second bottom fixing piece, and the other end is press-connected to the outer side surface of the second pressure plate; one side of the internal support structure is press-connected to the inner side of the hollow annular end face, and the other side is fixedly connected to the second bottom fixing piece, so as to realize the control of the axial vibration of the hollow annular end face during the turning process.

[0024] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0025] (1) The present invention adopts a special vertical lathe processing mold and a milling processing mold to process thin-walled parts with annular grooves on the end faces, and adopts a processing method of "rough processing-semi-finishing-finishing", thereby reducing deformation and mechanical damage caused by accumulated stress of thin-walled materials and improving processing accuracy; wherein each processing includes milling processing and one lathe processing in sequence. The present invention adopts a vertical lathe processing mold to gradually thin the outer circle of the side wall of the thin-walled part, and the rigidity of the side wall is gradually weakened. In the subsequent milling process, a guard plate is set in the milling processing mold to improve the rigidity of the side of the thin-walled part blank. When the thin-walled part blank is milled, the guard plate can provide support force in two radial directions, thereby reducing vibration and deformation in two radial directions; at the same time, in order to cope with the decrease in the rigidity of the side wall of the thin-walled part and avoid deformation of the side wall during vertical lathe processing, the present invention sets an internal support structure and an external support structure in the lathe processing mold to fix the second end face, thereby ensuring the dimensional accuracy of structures such as the side milling processing window.

[0026] (2) The present invention arranges a first pressing plate, a first bottom fixing member, a first pulling rod and a guard plate in the milling processing mold, thereby achieving the pressing and fixing of the thin-walled part while greatly reducing the adverse effects of vibration on the processing accuracy during side processing; and improves the defects of the prior art that the processing of the side of the thin-walled part from the inside to the outside is prone to vibration and poor processing accuracy.

[0027] (3) The present invention radially fixes the guard plate through the first pull rod and circumferentially presses it with the side surface, thereby improving the rigidity of the side surface of the thin-walled blank. When the milling tool processes the first groove, the guard plate provides circumferential support force for the side surface. The support force is opposite to the force direction of the milling tool, thereby making the thin-walled blank stable and not prone to vibration or deformation from the outside to the inside. On the one hand, the side surface of the guard plate and the circular arch structure of the guard plate can effectively disperse the force of the milling tool. On the other hand, the guard plate provides circumferential support force for the side surface, so that the guard plate uniformly applies force at each contact point with the side surface, thereby preventing deformation of the side surface of the thin-walled blank caused by local stress concentration. Therefore, when the thin-walled blank is milled, the guard plate can provide support force in two radial directions, thereby reducing vibration and deformation in two radial directions.

[0028] (4) The present invention uses laser scanning imaging technology to preliminarily determine the wall thickness of each section of the casting and determine the correction position of the rotation axis. Based on the corrected axis, the processing reference line is adjusted to coordinate the wall thickness of each processing part, so as to make the wall thickness of the parts as uniform as possible before processing. At the same time, the correction of the rotation axis can greatly improve the misalignment of the rotating shaft center and the geometric center of the cylindrical part and the eccentric vibration caused by the casting precision error of the blank.

[0029] (5) The present invention provides a positioning block on the inner side of the cast thin-walled blank, and uses the line connecting the center of the positioning block in the radial plane as the reference in the first vertical lathe process. This can greatly reduce the workload of machine tool alignment and zeroing in subsequent processes while meeting the accuracy requirements, thereby improving the processing accuracy.

[0030] (6) The present invention arranges an internal support structure and an external support structure in the turning mold, and provides a tightening and pressing force between the second pressure plate and the second bottom fixing member for the thin-walled part through the second pressure plate. The internal support structure and the second bottom fixing member provide a supporting force from the inside to the outside of the thin-walled part for the second end face. These two forces in opposite directions balance the forces on the second pressure plate, thereby fixing the second end face and reducing the deformation and vibration of the second end face during machining by the turning tool, thereby improving the machining accuracy.

[0031] (7) The present invention can achieve stable pressing and fixing of the corners of thin-walled parts by arranging a connecting pressure plate, an external support rod, and a second pull rod on the external support structure of the lathe processing mold, without having to use a long connecting pressure plate passing through the center area of ​​the second end surface as in the prior art. This also improves the defect of the prior art that the thin-walled part fixing mold interferes with the lathe tool processing.

[0032] (8) The present invention arranges the bottom of the guard plate to be fixedly connected to the first bottom fixing member, and the side of the guard plate is fitted and connected to the side of the thin-walled blank, so that the noise in the processing area during milling can be transmitted to the machine tool through the first bottom fixing member, thereby reducing the noise propagation into the air and reducing environmental noise.

[0033] (9) The present invention provides through holes in the guard plate to facilitate the monitoring of the wall thickness of each area during milling processing; at the same time, the through holes improve ventilation and heat dissipation during side processing, which is beneficial to preventing overheating of the blank processing surface, resulting in deformation or even damage and burning of the blank.

[0034] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0036] Figure 1 A schematic diagram of a 45° top view of a cylindrical thin-walled member having a groove on the thin-wall end surface in one embodiment of the present invention;

[0037] Figure 2 A schematic diagram of a cylindrical thin-walled member with a groove on the thin-wall end surface in a 45° bottom view in one embodiment of the present invention;

[0038] Figure 3 A 45° top view of a mold for milling thin-walled parts in one embodiment of the present invention;

[0039] Figure 4 A view showing the installation method of a mold for milling thin-walled parts in one embodiment of the present invention;

[0040] Figure 5 It is a cross-sectional view of the AA plane of the installation mode of the thin-walled part milling mold in one embodiment of the present invention;

[0041] Figure 6 A view showing the installation method of a thin-walled part turning mold in one embodiment of the present invention;

[0042] Figure 7 It is a BB-plane cross-sectional view of a thin-walled part turning die installation view in one embodiment of the present invention;

[0043] Figure 8 The present invention is a flowchart of a method for controlling vibration during machining of a cylindrical thin-walled part in one embodiment of the present invention.

[0044] Reference numerals:

[0045] Part blank 1; side 101; first end face 102; second end face 103; window 1011; positioning block 1012; first groove 1013; annular groove 1031; milling mold 2; first pressing plate 201; guard plate 202; first bottom fixing member 203; first pull rod 204; connecting structure 205; second through hole 2021; first through hole 2022; external support structure 301; second bottom fixing member 303; internal support structure 305; second pressing plate 307; connecting pressing plate 3011; external support rod 3012; second pull rod 3013; inner support plate 3051; inner support rod 3052. DETAILED DESCRIPTION

[0046] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0047] It should be noted that in the present invention, the axial direction is perpendicular to the two end surfaces of the thin-walled part, and the radial direction is parallel to the two end surfaces of the thin-walled part.

[0048] The present invention discloses a cylindrical thin-walled part, such as Figure 1 and Figure 2As shown, it includes: a first end face 102, a second end face 103 and a side surface 101 connecting the first end face 102 and the second end face 103; the first end face 102 is an unobstructed free end face, and the second end face 103 is a hollow annular end face; an annular groove 1031 is provided on the inner side of the hollow annular shape of the second end face 103.

[0049] like Figure 1 As shown, the side surface 101 is provided with a plurality of windows 1011, and at least one group of windows 1011 is symmetrically arranged relative to the axis center of the thin-walled part; after the thin-walled part blank is fixed by a milling mold, a milling tool penetrates into the thin-walled part blank through the first end surface 102, and the windows 1011 in the side surface 101 are processed to obtain windows 1011 that meet the target size.

[0050] It should be noted that the thin-walled blank is obtained by casting, and the dimensional accuracy of the window 1011 and other dimensions in the blank obtained by casting cannot meet the requirements, so a milling tool is required to further process it to obtain the specified shape and accuracy.

[0051] It should be noted that Figure 2 The middle annular groove 1031 needs to be obtained by fixing the thin-walled blank with a turning mold and then machining the second end surface 103 with a turning tool.

[0052] A plurality of positioning blocks 1012 are disposed on the side surface 101 of the thin-walled member, and at least one group of positioning blocks 1012 is symmetrically disposed relative to the axis center of the thin-walled member.

[0053] It should be noted that the side 101 of the part blank 1 has multiple windows 1011, and the part blank needs to be rotated by milling to process the windows 1011 one by one. Therefore, it is necessary to determine the rotation angle of the part blank 1 and the rotating platform connected to it to match the processing of the next window 1011 after completing the processing of the adjacent windows 1011.

[0054] like Figure 1 As shown, a plurality of spaced first grooves 1013 are provided on the side surface 101 close to the first end surface 102 .

[0055] During implementation, the first groove 1013 is obtained by machining the side surface 101 from the outside to the inside using a milling tool.

[0056] The thin-walled component has a thin-wall characteristic. Specifically, the ratio of the wall thickness of the first end face 102 , the second end face 103 , and the side face 101 to the outer diameter of the thin-walled component is 1:200-1000.

[0057] It should be noted that vibration and deformation are mainly affected by the relative value of wall thickness and part diameter. The smaller the relative ratio of wall thickness to part diameter, the part exhibits obvious thin-wall characteristics, and the machining accuracy is significantly reduced due to machining vibration and deformation.

[0058] Specifically, the thin-walled parts can be made of any one of carbon steel, stainless steel, titanium alloy, aluminum alloy, and magnesium alloy.

[0059] In summary, the deformation of the above-mentioned cylindrical thin-walled parts requires the use of vertical lathe processing for outer circumferential processing and end face circumferential processing, and the use of milling machine processing for radial processing of the side of the part blank; therefore, the forming process of the cylindrical thin-walled parts will be subject to axial and radial external forces, and the cylindrical thin-walled parts are prone to vibration in these two directions, affecting the forming shape and precision.

[0060] In addition, due to the inevitable errors in the blanks of cast parts, they are manifested as: the rotation axis of the blank does not coincide with the geometric center, and the wall thickness is uneven. When the cast blank is directly processed, eccentric vibration is inevitable during the rotation of the rotary table, affecting the molding shape and precision.

[0061] On the other hand, the present invention provides a method for controlling vibration during the processing of a cylindrical thin-walled part, so as to solve the problem of radial and axial vibration of the cylindrical thin-walled part, wherein the processing process includes milling of the side surface of the cylindrical thin-walled part and lathing of the end surface and outer circle of the cylindrical thin-walled part, and the vibration includes radial vibration and axial vibration; Figure 8 As shown, the method for controlling tremor includes:

[0062] A guard plate is arranged around the circumferential side of the milling mold, and the guard plate is tightly fitted and fixed to the side, so that the side is radially fixed to the milling mold through the guard plate, so as to control the radial vibration of the side during the milling process;

[0063] An external support structure and an internal support structure are arranged on the turning mold, the external support structure is pressed to support the outer side surface of the hollow annular end surface, and the internal support structure is pressed to support the inner side surface of the hollow annular end surface, so as to control the axial vibration of the hollow annular end surface during the turning process.

[0064] Specifically, regarding the control of the lateral radial vibration during milling and the control of the axial vibration during milling: Figure 3 , Figure 4 and Figure 5 As shown: a first pressing plate 201 pressed and connected to the first end surface 102 is provided at one end of the milling mold 2, and a first bottom fixing piece 203 pressed and connected to the second end surface 103 is provided at the other end.

[0065] Specifically, the first pressing plate 201 is a hollow annular structure, and a milling tool enters the inside of the thin-walled part from the first end surface 102 to perform milling or milling on the outside of the thin-walled part.

[0066] At the same time, the milling mold is also provided with a first pull rod 204 connecting the first pressure plate 201 and the first bottom fixing piece 203; the circumferential outer edge of the first pressure plate 201 and the circumferential outer edge of the first bottom fixing piece 203 are fixedly connected through the first pull rod 204, and the first bottom fixing piece 203 is fixedly connected to the machine tool platform; the first pull rod 204 provides a tightening force along the direction of the first pull rod 204 to realize the pressing and fixing of the thin-walled parts on the machine tool platform.

[0067] There are multiple first tie rods 204 arranged circumferentially along the side surface 101, and the milling mold is provided with a guard plate 202 on the side surface 101 of the thin-walled part to limit the radial vibration of the thin-walled part; the guard plate 202 surrounds the side surface 101 circumferentially and is provided with a first through hole 2022 arranged axially; the first through hole 2022 corresponds to the first tie rod 204 one by one; the first tie rod 204 passes through the first through hole 2022; the first tie rod 204 arranged circumferentially along the side surface 101 makes the guard plate 202 radially fixed; at the same time, the guard plate 202 and the side surface 101 are circumferentially fitted to generate a sufficiently large static friction force, so as to achieve the axial fixation of the guard plate 202, thereby achieving the fixation of the guard plate 202. When the guard plate 202 is used by the milling machine tool to process the inner wall of the side surface 101, the guard plate 202 is arranged circumferentially in contact with the side surface 101, which can limit the deformation or vibration of the thin-walled part radially outward.

[0068] It should be noted that the milling machine tool processes the side 101 of the thin-walled part gradually from the inside to the outside of the thin-walled part, thereby applying a radial outward force to the side 101, which can easily cause deformation or vibration of the side 101; when the wall thickness of the machined blank becomes thinner, the adverse effects of deformation or vibration on the machining accuracy will further increase.

[0069] Compared with the prior art, the present invention arranges a first pressing plate 201, a first bottom fixing piece 203, a first pull rod 204 and a guard plate 202 in the milling mold, thereby achieving the pressing and fixing of the thin-walled parts, while greatly reducing the adverse effects of vibration on the processing accuracy during side processing; and improves the defects of the prior art that the side of the thin-walled parts is prone to vibration and poor processing accuracy when processed from the inside to the outside.

[0070] Specifically, Figure 4 , Figure 5 As shown, the first end face 102 of the thin-walled part is pressed and connected with the first pressure plate 201; the second end face 103 is pressed and connected with the first bottom fixing part 203; the two ends of the first pull rod 204 are respectively fixedly connected with the circumferential edges of the first pressure plate 201 and the first bottom fixing part 203; the first pull rod 204 is arranged along the circumferential edges of the first pressure plate 201 and the first bottom fixing part 203, and passes through the first through hole 2022, so that the guard plate 202 is radially fixed and circumferentially pressed with the side surface 101; the pressed guard plate 202 and the side surface 101 generate sufficient static friction force to realize axial fixation of the guard plate 202 and the side surface 101.

[0071] Specifically, the side of the guard plate 202 is further provided with a plurality of radially arranged second through holes 2021 for use in detecting the wall thickness of the side surface 101 by an external device and for ventilation and heat dissipation of the side surface of the blank during processing.

[0072] Compared with the prior art, the present invention provides a second through hole so that the side wall thickness can be measured during milling, and ventilation and heat dissipation are achieved through the through hole, thereby solving the problems of difficulty in thickness control and poor heat dissipation in the prior art of side wall processing of thin-walled parts.

[0073] It should be noted that heat dissipation has always been a key issue in the processing of thin-walled parts, especially magnesium alloy parts. Excessive heat accumulation can cause the magnesium alloy to soften, deform, or even burn. Magnesium alloy is one of the few metals that can react with nitrogen and oxygen in the air at the same time, so temperature control is particularly important during processing.

[0074] Preferably, the guard plate 202 is formed by axially splicing two guard plate units, and the guard plate 202 is provided with a connection structure 205 with an adjustable connection gap at the connection between the two guard plate units, so that the guard plate 202 can match thin-walled blanks with different outer diameters and adjust the degree of pressing between the guard plate 202 and the side 101; when the pressing force is large enough, the guard plate 202 and the side 101 generate a sufficiently large static friction force to achieve axial fixation of the guard plate 202.

[0075] In order to realize the processing of the first groove 1013 on the side surface 101, the height of the guard plate 202 is set to be lower than the height of the thin-walled part blank.

[0076] Specifically, the milling tool processes the first groove 1013 from the outside to the inside through the gap between the guard plate 202 and the first pressing plate 201 .

[0077] Preferably, the wall thickness of the guard plate 202 is greater than the wall thickness of the thin-walled blank.

[0078] It should be noted that the guard plate 202 is radially fixed by the first pull rod 204 and is circumferentially pressed with the side 101. At the same time, the wall thickness of the guard plate 202 is much greater than that of the thin-walled blank, which improves the rigidity of the side of the thin-walled blank. When the milling tool processes the first groove 1013, the guard plate 202 provides circumferential support force for the side 101. The support force is opposite to the force direction of the milling tool, thereby making the thin-walled blank stable and not prone to vibration or deformation from the outside to the inside.

[0079] On the one hand, the side of the guard plate 202 and the arched structure of the guard plate 202 can effectively disperse the force of the milling tool; on the other hand, the guard plate 202 provides circumferential support for the side 101, so that the guard plate 202 applies force evenly at each contact point with the side 101, thereby preventing deformation of the side of the thin-walled blank caused by local stress concentration.

[0080] Compared with the prior art, the guard plate 202 is arranged to surround and fit the side of the thin-walled blank, and can provide support force in two radial directions when the side of the thin-walled blank is milled, thereby reducing vibration and deformation in two radial directions.

[0081] Specifically, the first pull rod is detachably fixedly connected to the first pressing plate and the first bottom fixing piece.

[0082] Preferably, the connection area between the first pull rod and the first pressing plate and the first bottom fixing piece is provided with threads, and the first pull rod and the first pressing plate and the first bottom fixing piece are fixedly connected with each other by means of nuts matching the threads.

[0083] Preferably, the first pull rod is symmetrically arranged relative to the axis center of the thin-walled member, providing uniform pressure to the thin-walled member in the radial direction.

[0084] Specifically, a milling die is used to fix the free end surface of the thin-walled blank on a rotating worktable, including:

[0085] S101: The first pressing plate of the milling mold is pressed and connected with the first end surface, and the first bottom fixing piece is pressed and connected with the second end surface;

[0086] S102: fixing the circumferential outer edge of the first pressing plate to the corresponding position of the circumferential outer edge of the first bottom fixing member through a first pull rod, and fixing the first bottom fixing member to the machine tool platform;

[0087] S103: Pass the first pull rod through the first through hole circumferentially arranged on the side surface, and the first pull rod circumferentially arranged along the side surface enables the guard plate to circumferentially fit the side surface.

[0088] Specifically, regarding the control of the overall axial vibration of the thin-walled part and the control of the axial vibration of the hollow annular end face during the turning process: the turning mold is fixedly connected to the first end face and the second end face of the thin-walled part at the same time, so that the thin-walled part is fixed to the turning mold. The turning mold is provided with an external support structure and an internal support structure. The external support structure supports the outer side surface of the second end face, and the internal support structure supports the inner side surface of the second end face.

[0089] Specifically, Figure 6 , Figure 7 As shown, the turning mold includes: a second pressing plate 307, a second bottom fixing piece 303; one end of the external supporting structure 301 is fixedly connected to the second bottom fixing piece 303, and the other end is press-fitted to the outer side surface of the second pressing plate 307; the inner side surface of the second pressing plate 307 is press-fitted to the outer side of the second end surface 103, and the external supporting structure 301 provides a tightening and pressing force between the second pressing plate 307 and the second bottom fixing piece 303 for the thin-walled part through the second pressing plate 307.

[0090] At the same time, one side of the internal support structure 305 is pressed and connected to the inner side of the second end face 103, and the other side is fixedly connected to the second bottom fixing piece 303. The internal support structure 305 and the second bottom fixing piece 303 provide supporting force from the inside to the outside of the thin-walled part for the second end face 103.

[0091] Specifically, the second end surface 103 partially overlaps with the pressing area of ​​the second pressing plate 307 , and the annular center edge of the second end surface 103 is provided with an area that is not blocked by the second pressing plate 307 and is used for processing the annular groove 1031 .

[0092] Optionally, the internal support structure 305 completely overlaps with the area of ​​the second pressing plate 307 used for processing the annular groove 1031 , and the internal support structure 305 is supported by the processing area of ​​the annular groove 1031 on the inner side of the second pressing plate 307 .

[0093] It should be noted that the turning tool processes the annular groove 1031 from shallow to deep on the outside of the second end face 103. At this time, the turning tool applies a pressing force from the outside to the inside to the second end face 103. Under the action of this force, the second end face 103 will also deform or vibrate, thereby affecting the processing accuracy. The smaller the wall thickness of the thin-walled part, the greater the impact of deformation or vibration on the accuracy, and the processing difficulty of the part increases accordingly.

[0094] Compared with the prior art, the present invention provides a tightening and pressing force between the second pressure plate and the second bottom fixing member for the thin-walled member by setting an internal supporting structure and an external supporting structure. The internal supporting structure and the second bottom fixing member provide a supporting force from the inside to the outside of the thin-walled member for the second end face. These two forces in opposite directions balance the forces on the second pressure plate, thereby fixing the second end face and reducing the deformation and vibration of the second end face during machining with a turning tool, thereby improving machining accuracy.

[0095] Specifically, in order to achieve the pressing and fixing of thin-walled parts during turning, such as Figure 7 As shown, the external support structure 301 is provided with a connecting pressure plate 3011, a second pull rod 3013 and an external support rod 3012; the connecting pressure plate 3011 is provided with a through hole; the second pull rod 3013 corresponds to the through hole one by one, one end of the second pull rod 3013 passes through the through hole and is fixedly connected to the connecting pressure plate 3011, and the other end is fixedly connected to the second bottom fixing member 303; a group of side surfaces penetrated by the through hole are arranged parallel to the second pressure plate 307, and one side surface of the group of side surfaces is pressed and abutted against the outer edge of the second pressure plate 307.

[0096] When implementing, Figure 6 As shown, the second pressing plate 307 is an annular flat plate, and the connecting pressing plate 3011 is a rectangular connecting block pressed on the outer edge of the annular flat plate.

[0097] Optionally, a threaded structure is provided at the end of the second pull rod 3013 , and the second pull rod 3013 passes through the connecting pressure plate 3011 and is fixedly connected to the connecting pressure plate 3011 through a nut.

[0098] It should be noted that the connecting pressure plate 3011 is pressed onto the outer edge of the annular flat plate of the second pressure plate 307 and is fixed to the second bottom fixing member 303 by the second pull rod 3013. Therefore, the connection point between the second pull rod 3013 and the second pressure plate 307 and the force points of the connecting pressure plate and the second pressure plate 307 do not coincide. The connecting pressure plate is subjected to reverse stress while being pressed onto the second pressure plate 307, which makes the pressing and fixing method of the connecting pressure plate 3011 and the second pressure plate 307 easy to loosen.

[0099] Furthermore, in order to solve the problem that the connecting pressure plate 3011 and the second pressure plate 307 are easily loosened and fall off, the external support structure 301 is provided with an external support rod 3012; one end of the external support rod 3012 is fixedly connected to the connecting pressure plate 3011, and the other end is fixedly connected to the second bottom fixing member 303, and is arranged away from the thin-walled member relative to the second pull rod 3013.

[0100] Compared with the prior art, the present invention can achieve stable pressing and fixing of the corners of thin-walled parts by arranging a connecting pressure plate 3011, an external support rod 3012, and a second pull rod 3013 on the external support structure 301, without having to use a long connecting pressure plate passing through the center area of ​​the second end surface as in the prior art, thereby improving the defect of the prior art that the thin-walled part fixing mold interferes with the lathe tool processing.

[0101] Specifically, in order to achieve inner support for the second end face 103, the internal support structure 305 is provided with an inner support plate 3051 and an inner support rod 3052; the inner support plate 3051 is in a circular ring shape, and is coaxially matched with the second end face 103, providing the second end face 103 with a support force from the inner side in the opposite direction to the pressing force of the connecting pressure plate 3011; one end of the inner support rod 3052 is fixedly connected to the inner support plate 3051, and the other end is fixedly connected to the second bottom fixing member 303, providing the inner support plate 3051 with a support force from the inside to the outside in the opposite direction to the pressing force of the connecting pressure plate 3011.

[0102] Optionally, the inner support plate 3051 completely overlaps with the processing area of ​​the annular groove 1031, providing a supporting force for the processing of the annular groove 1031 that is opposite to the pressing force of the connecting pressure plate 3011; this can greatly improve the deformation and vibration caused by processing the groove of thin-walled parts.

[0103] Specifically, a lathe die is used to fix the free end surface of the thin-walled blank on a rotating worktable, including:

[0104] S201: One end of the external support structure is fixedly connected to the second bottom fixing member, and the other end is press-fitted to the outer side surface of the second pressing plate; the inner side surface of the second pressing plate is press-fitted to the outer side of the second end surface;

[0105] S202: One side of the internal support structure is press-fitted to the inner side of the second end surface, and the other side is fixedly connected to the second bottom fixing member.

[0106] The vibration also includes eccentric vibration. The eccentric vibration control method includes: correcting the axis of the thin-walled blank based on the fitting image of the thin-walled blank and the theoretical image of the thin-walled blank, performing vertical lathe processing based on the corrected axis to obtain a thin-walled blank with uniform wall thickness, realizing the control of eccentric vibration during processing, and solving the eccentric vibration problem caused by poor casting accuracy of the thin-walled blank.

[0107] Specifically, regarding eccentric tremor:

[0108] The method of obtaining a thin-walled blank with uniform wall thickness comprises:

[0109] S301: Connect the centers of the positioning blocks that are symmetrical relative to the axis center as the reference positioning lines of the hollow annular end face, obtain the fitting image of the thin-walled blank based on the laser scanning fitting imaging, and correct the reference positioning lines based on the fitting image of the thin-walled blank; the thin-walled blank has a side surface, an unobstructed free end surface and a hollow annular end surface; the inner surface of the side surface is provided with at least two positioning blocks that are symmetrical relative to the axis center.

[0110] Specifically, the laser scanning fitting imaging analysis software is used to synthesize the fitting image of the thin-walled blank from the information of the cast part blank obtained by laser scanning; based on the fitting image of the part blank and the theoretical image of the thin-walled blank, the deviation of the fitting image of the thin-walled blank and its theoretical image in each radial section is obtained; and the deviation of each radial section is judged:

[0111] If the radial section deviation is less than or equal to the first threshold δ 1 , without any adjustment, the reference positioning line is calibrated;

[0112] If the radial section deviation is greater than the first threshold δ 1 , adjust the position of the axis of the theoretical image of the thin-walled blank until the deviation of each radial section is less than or equal to the first threshold δ 1 , record the position change value △(x, y, z) of the axis line in the spatial coordinate system; in the same spatial coordinate system, change the axis line of the part blank according to △(x, y, z) to obtain the axis line coordinates of the corrected part blank; connect the center of the positioning block and the axis line of the corrected part blank in the radial plane, and use the line connecting the two as the corrected reference positioning line.

[0113] During implementation, the thin-walled blank is a hollow thin-walled blank with two end faces obtained by casting. During processing, the end faces are fixed on a rotating platform and can rotate freely around the axis; the two end faces are arranged parallel to the radial plane.

[0114] During implementation, the positioning blocks are cast together with the thin-walled blank in a mold, and may be a structure with a regular shape that is convenient for finding the center, such as a cuboid; multiple groups of positioning blocks may be provided, and each pair is symmetrical relative to the axis center.

[0115] It should be noted that the setting accuracy of the positioning block on the thin-walled blank meets the preliminary alignment requirements, which allows the processing personnel to roughly judge the position of the reference line and facilitates the adjustment of the rotation angle of the thin-walled blank, so that the starting processing position of the thin-walled blank is close to the processing area.

[0116] It should be noted that the thin-walled blank obtained by casting has uneven wall thickness on the side, which is not the ideal uniform wall thickness state; if it is processed according to the original design axis, it is inevitable to obtain a product with uneven wall thickness; therefore, it is necessary to correct the axis position so that this position can be used as the axis to rotate and process the thin-walled blank to obtain a product with uniform wall thickness.

[0117] During implementation, the spatial coordinate system often uses the axial direction of the thin-walled part as one coordinate axis and the radial direction as the plane where the other two coordinate axes are located; the laser scanning fitting imaging analysis software can simultaneously display the fitting image of the part blank and the theoretical image of the thin-walled part blank, calculate the non-overlapping area between the two, and give different color labels. Through the color labels, the radial plane deviations of the thin-walled part can be intuitively obtained; by adjusting the axis centerline position of the fitting image of the part blank, the color label of each radial plane deviation changes, and then the position where the relative minimum radial plane deviation is obtained can be screened out. This position is used as the corrected position of the axis centerline of the part blank, and the position change value △(x, y, z) is calculated; in the spatial coordinate system where the part blank is fixed during processing, its axis centerline is changed according to △(x, y, z) to obtain the corrected position of the axis centerline of the part blank, and any positioning block in a group of positioning blocks that are symmetrical relative to the axis centerline is selected, and the center of the positioning block and the axis centerline of the corrected part blank are connected in the radial plane. The line connecting the two is used as the corrected reference positioning line to complete the correction of the reference positioning line.

[0118] S302: performing vertical lathe processing on both end faces and the outer circle of the side of the thin-walled blank after the calibration of the reference positioning line, so as to obtain a thin-walled blank with uniform wall thickness.

[0119] Specifically, a three-jaw clamp is used to fix the thin-walled blank from the inside, the free end face of the thin-walled blank is fixed on a rotating worktable, and the hollow annular end face is arranged near the turning tool end; the turning tool turns the two end faces and the outer circle of the side of the thin-walled blank from the hollow annular end face to the free end face.

[0120] It should be noted that the three-jaw clamp is a commonly used internal fixing clamp for lathes. It has three jaws and the distance between the three jaws can be adjusted to clamp and fix hollow parts with different inner diameters from the inside of the hollow parts.

[0121] It should be noted that the vertical lathe processing with allowance mentioned in this article means that the vertical lathe processing has not been processed to the size of the formed component, and there is allowance for further vertical lathe processing.

[0122] It should be noted that the axis line of the thin-walled part blank that has completed the reference positioning line correction is the corrected position for turning, and the side of the thin-walled part blank obtained by rotation turning along this axis line has a more uniform wall thickness; after vertical turning, the cross-sectional shape of the part blank is changed compared with the original thin-walled part blank, the wall thickness is uniform, and the center of the cross-sectional area of ​​the part blank is located on the corrected axis line.

[0123] Compared with the prior art, on the one hand, the present invention adopts a special vertical lathe processing mold and a milling processing mold to process thin-walled parts with annular grooves on the end faces, and adopts a "rough machining-semi-finishing-finishing" processing method, which reduces the deformation and mechanical damage caused by the accumulated stress of the thin-walled material and improves the processing accuracy; wherein, each processing includes a milling process and a turning process. The present invention adopts a vertical lathe processing mold to gradually thin the outer circle of the side wall of the thin-walled part, and the rigidity of the side wall is gradually weakened. In the subsequent milling process, a guard plate is set in the milling processing mold to improve the rigidity of the side of the thin-walled part blank. When the thin-walled part blank is milled, the guard plate can provide support force in two radial directions, thereby reducing vibration and deformation in two radial directions; at the same time, in order to cope with the decrease in the rigidity of the side wall of the thin-walled part and avoid deformation of the side wall during vertical lathe processing, the present invention sets an internal support structure and an external support structure in the turning mold to fix the second end face, thereby ensuring the dimensional accuracy of structures such as the side milling processing window.

[0124] On the other hand, the present invention arranges a first pressure plate, a first bottom fixing part, a first pull rod, and a guard plate in the milling mold, thereby achieving the pressing and fixing of the thin-walled parts, while greatly reducing the adverse effects of vibration on the processing accuracy during side processing; and improves the defects of the prior art that the side of the thin-walled parts is prone to vibration and poor processing accuracy when milling from the inside to the outside.

[0125] In addition, the present invention adopts laser scanning imaging technology to preliminarily determine the wall thickness of each section of the casting, determine the correction position of the rotation axis centerline, and adjust the processing reference line based on the corrected axis centerline to coordinate the wall thickness of each processing part, so as to make the wall thickness of the parts as uniform as possible before processing, so as to ensure that the processing allowance of each surface is uniform and the wall thickness meets the requirements. While ensuring the accuracy of the reference marking, the workload of machine tool alignment and zeroing in subsequent processes is greatly reduced.

[0126] In addition, the present invention provides a positioning block on the inner side of the cast thin-walled blank, and uses the line connecting the center of the positioning block in the radial plane as the reference in the first vertical lathe process, which can greatly reduce the workload of machine tool alignment and zeroing in subsequent processes on the basis of meeting the accuracy requirements; and further uses the positioning block and the rotation axis centerline correction position to determine the processing reference positioning line; and further sets a reference hole on the processing reference positioning line as a transmission medium for the original reference, thereby ensuring the continuation of the reference and improving the processing accuracy.

[0127] In addition, the present invention removes deformation and precision errors in the casting process by vertical lathe processing on the blank after the positioning reference line and axis are corrected, so that the rotation axis of the blank coincides with the geometric center of its end face, and the positioning reference line is combined to provide a reference for the next step of processing.

[0128] Specifically, S301 obtains a fitting image of a thin-walled workpiece blank based on laser scanning fitting imaging, including: using sensors densely distributed on the inner and outer surfaces of the thin-walled workpiece blank as data sampling points, using laser scanning to obtain the coordinates of the sensors in the spatial coordinate system, and fitting a three-dimensional image of the thin-walled workpiece blank according to the spatial coordinate information of the sensors.

[0129] Specifically, the step of correcting the axis of the thin-walled workpiece blank based on the fitting image of the thin-walled workpiece blank in S301 includes:

[0130] S3011: Using laser scanning fitting imaging software, the fitting image of the part blank and the axis line of the theoretical image of the thin-walled part blank are overlapped, the thickness of each area of ​​the radial section of the part blank is compared, the deviation is automatically obtained and color-coded according to the deviation size;

[0131] S3012: If the radial section deviations are less than or equal to the first threshold δ 1 , without any adjustment, the reference positioning line is calibrated;

[0132] If the radial section deviation is greater than the first threshold δ 1 , adjust the position of the axis of the theoretical image of the thin-walled blank until the deviation of each radial section is less than or equal to the first threshold δ 1 , record the position change value △(x, y, z) of the axis centerline in the spatial coordinate system;

[0133] S3013: Construct a spatial coordinate system that is the same as the fitting image of the part blank and the theoretical image of the thin-walled part blank, and change the axis of the part blank according to △(x, y, z) in the coordinate system to obtain the axis coordinates of the corrected part blank.

[0134] It should be noted that the first threshold δ 1 The determination of is related to the accuracy of the dial indicator itself. The first threshold δ 1<0.02mm, which exceeds the accuracy range of the dial indicator.

[0135] Specifically, the vertical lathe processing in S302 includes the following steps:

[0136] S3021: select 1 / 4 to 1 / 2 of the machining amount of the vertical lathe for the fixed thin-walled blank, perform trial machining, and obtain a trial machining blank sample;

[0137] S3022: Detect the eccentricity of the test blank sample rotating around the axis of the corrected part blank;

[0138] S3023: judging the eccentricity;

[0139] If the eccentricity is less than the second threshold δ 2 , then turn processing;

[0140] If the eccentricity is greater than the second threshold δ 2 , then repeat S3012-S3013 to correct the axis line of the part blank again until the eccentricity is less than the second threshold value δ 2 .

[0141] Specifically, the eccentricity described in S3022 is tested by a dial indicator, which includes the following steps: fixing the fixed end of the dial indicator to the machine tool platform, and contacting the test end with the side of the part blank until a reading is shown; recording the change in the percentage indicator reading during one rotation of the part blank.

[0142] Specifically, the eccentricity is evaluated by the change in the dial indicator pointer reading η, and η satisfies: η=S max -S min , where S max S is the maximum value of the dial indicator pointer. min It is the minimum value indicated by the dial indicator pointer.

[0143] Optionally, the second threshold δ 2 Set to 0.02mm.

[0144] It should be noted that the second threshold δ 2 The determination of is related to the accuracy of the dial indicator itself. The second threshold δ 2 <0.02mm, which exceeds the accuracy range of the dial indicator.

[0145] In order to meet the requirements of magnesium alloy processing, the feed rate of the part blank is 0.4mm / r~0.6mm / r during the first turning process; if it is lower than 0.4mm / r, local overheating is likely to occur, causing deformation of the magnesium alloy or even spontaneous combustion; if it is higher than 0.6mm / r, it is difficult to meet the precision requirements.

[0146] In order to improve local heat dissipation, a cooling airflow of 0.6MPa to 0.8MPa is applied during the processing of the blank parts.

[0147] It should be noted that water or oil-based cutting coolants will react with high-temperature magnesium alloys. Compared with the prior art, the present invention uses 0.6MPa to 0.8MPa of air-cooled airflow for cooling, which solves the problem of local heat dissipation and is conducive to further reducing the feed rate and improving processing accuracy and processing safety.

[0148] In order to reduce the deformation during processing, the cutting depth of the part blank is 0.5 to 2; if the cutting depth of the part blank is greater than 2, deformation is likely to occur when fixed by an ordinary three-jaw clamp.

[0149] Specifically, the machining volume of the vertical lathe is 2 mm to 4 mm.

[0150] Preferably, the machining amount of the vertical lathe machining is 3 mm.

[0151] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. Methods for controlling vibration during machining of cylindrical thin-walled parts. It is characterized in that The processing process includes milling of the side of the cylindrical thin-walled part and lathing of the end face and outer circle of the cylindrical thin-walled part. The vibration includes radial vibration and axial vibration. The method for controlling the vibration includes: A guard plate is arranged around the circumferential side of the milling mold, and the guard plate is tightly fitted and fixed to the side, so that the side is radially fixed to the milling mold through the guard plate, so as to control the radial vibration of the side during the milling process; An external support structure and an internal support structure are arranged on the lathe processing mold, the external support structure is pressed to support the outer side surface of the hollow annular end surface, and the internal support structure is pressed to support the inner side surface of the hollow annular end surface, so as to control the axial vibration of the hollow annular end surface during lathe processing; The vibration also includes eccentric vibration, and the eccentric vibration control method includes: correcting the axis of the thin-walled blank based on the fitting image of the thin-walled blank and the theoretical image of the thin-walled blank, performing vertical lathe processing based on the corrected axis, obtaining a thin-walled blank with uniform wall thickness, and realizing the control of eccentric vibration during processing; The method of obtaining a thin-walled blank with uniform wall thickness comprises: S301: connecting the centers of the positioning blocks symmetrical with respect to the axis center as the reference positioning line of the hollow annular end face, obtaining a fitting image of the thin-walled blank based on laser scanning fitting imaging, and correcting the reference positioning line based on the fitting image of the thin-walled blank; the thin-walled blank has a side surface, an unobstructed free end surface and a hollow annular end surface; the inner surface of the side surface is provided with at least two positioning blocks symmetrical with respect to the axis center; S302: performing vertical lathe processing on both end faces and the outer circle of the side of the thin-walled blank after the reference positioning line correction is completed, so as to obtain a thin-walled blank with uniform wall thickness; The step of correcting the axis of the thin-walled workpiece blank based on the fitting image of the thin-walled workpiece blank comprises: S3011: Using laser scanning fitting imaging software, the fitting image of the part blank and the axis line of the theoretical image of the thin-walled part blank are overlapped and combined, the thickness of each area of ​​the radial section of the part blank is compared, the deviation is automatically obtained and color-coded according to the deviation size; S3012: If the radial section deviations are less than or equal to the first threshold δ 1 , without any adjustment, the reference positioning line is calibrated; If the radial section deviation is greater than the first threshold δ 1 , adjust the position of the axis of the theoretical image of the thin-walled blank until the deviation of each radial section is less than or equal to the first threshold δ 1 , record the position change value △(x, y, z) of the axis centerline in the spatial coordinate system; S3013: Construct a spatial coordinate system that is the same as the fitting image of the part blank and the theoretical image of the thin-walled part blank, and change the axis of the part blank according to △(x, y, z) in the coordinate system to obtain the axis coordinates of the corrected part blank.

2. The method according to claim 1, It is characterized in that The method for acquiring the fitting image of the thin-walled blank comprises: using sensors densely distributed on the inner and outer surfaces of the thin-walled blank as data sampling points, acquiring the coordinates of the sensors in the spatial coordinate system by laser scanning, and fitting a three-dimensional image of the thin-walled blank according to the spatial coordinate information of the sensors.

3. The method according to claim 1, It is characterized in that The vibration control method also includes the control of axial vibration during the milling process: radial vibration fixes the milling mold to the two end faces of the cylindrical thin-walled part at the same time, so that the two end faces of the thin-walled part are axially fixed to the milling mold, and the control of axial vibration during the milling process is achieved.

4. The method according to claim 3, It is characterized in that One end of the milling die is provided with a first pressing plate pressed and connected thereto, and the other end is provided with a first bottom fixing piece pressed and connected thereto; the milling die is also provided with a first pull rod connecting the first pressing plate and the first bottom fixing piece.

5. The method according to claim 4, It is characterized in that The first pull rods are arranged in plurality along the circumferential direction of the side surface, and a milling mold is provided with a guard plate on the side surface of the thin-walled part to limit the radial vibration of the thin-walled part; the guard plate circumferentially surrounds the side surface and is provided with a first through hole arranged axially; the first through hole corresponds one to one with the first pull rod; the first pull rod passes through the first through hole to fix the guard plate radially; at the same time, the guard plate and the side surface are circumferentially fitted to generate a sufficiently large static friction force to achieve axial fixation of the guard plate; the guard plate is circumferentially fitted to the side surface to limit the radial deformation or vibration of the thin-walled part toward the outside.

6. The method according to claim 1, It is characterized in that The vibration control method also includes controlling the overall axial vibration of the thin-walled part during turning: the turning mold is fixedly connected to the two end surfaces of the cylindrical thin-walled part at the same time, so that the two end surfaces of the thin-walled part are axially fixed to the turning mold, and the overall axial vibration of the thin-walled part during turning is controlled.

7. The method according to claim 6, It is characterized in that One end of the turning mold is provided with a second pressing plate press-connected thereto, and the other end is provided with a second bottom fixing piece press-connected thereto, and the second pressing plate is press-connected to the hollow annular end face; one end of the external support structure is fixedly connected to the second bottom fixing piece, and the other end is press-connected to the outer side surface of the second pressing plate; one side of the internal support structure is press-connected to the inner side of the hollow annular end face, and the other side is fixedly connected to the second bottom fixing piece, so as to realize the control of the axial vibration of the hollow annular end face during the turning process.

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