Processing die and processing method for thin-walled parts with annular grooves on the end faces

Abstract

The present invention relates to the technical field of light alloy manufacturing, and in particular to a processing mold and processing method for a thin-walled part with an annular groove on the end face; the processing mold comprises: a milling processing mold for processing the inner wall of the side of the thin-walled part and a lathe processing mold for processing the thin-walled end face with an annular groove; the milling processing mold is provided with a protective plate surrounding the side surface in a circumferential direction on the side of the thin-walled part; the lathe processing mold is provided with an external support structure for pressing the outside of the central annular end face of the thin-walled part and an internal support structure for supporting the inside of the central annular end face of the thin-walled part, and the external support structure and the internal support structure are used to keep the thin-walled part stable when processing the annular groove. The processing mold solves the deformation and vibration of the second end face during lathe processing and the side vibration during milling processing, and realizes high-precision and stable processing of the side wall and end face of magnesium alloy thin-walled parts.

Description

Technical Field

[0001] The invention relates to the technical field of light alloy manufacturing, and in particular to a processing die and a processing method for a thin-walled part with an annular groove on the end surface. Background Art

[0002] Large 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 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 machine tool processing of thin-walled parts often adopts a support and fixation method inside the part cavity. On the one hand, this type of mold fixation occupies the space of the part cavity, 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 mold determine that it can only be fixed at one axial end of the part to be processed, and an open end is left at the other end for the lathe spindle to enter and exit, resulting in a lack of mold fixation at the open end, resulting in particularly severe vibration, which seriously affects 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.

[0004] At present, the market is in urgent need of a processing equipment and method for large magnesium alloy thin-walled parts to solve the problems of fixation and reduced processing accuracy due to vibration during processing of large magnesium alloy thin-walled parts. In addition, during the fine processing of magnesium alloy materials, due to the slow tool speed, magnesium alloy is easy to oxidize or even burn, and there are always serious safety hazards in magnesium alloy processing; if the tool speed is too fast, the instability of the contact between the tool and the magnesium alloy will increase, further aggravating the vibration; therefore, it is urgent to improve the magnesium alloy machine tool processing technology in the existing technology. Summary of the invention

[0005] In view of the above analysis, the present invention aims to provide a processing mold and a processing method for a thin-walled part with an annular groove on the end face, so as to solve at least one of the problems in the prior art, such as poor mold fixing stability, easy vibration and poor safety of magnesium alloy processing.

[0006] The purpose of the present invention is mainly achieved through the following technical solutions:

[0007] The present invention provides a processing die for a thin-walled part with an annular groove on a thin-walled end face, comprising: a milling die and a lathe die; the thin-walled part comprises: a first end face, a second end face and a side surface connecting the first end face and the second end face; the first end face is an unobstructed free end face, and the second end face is a hollow annular end face; an annular groove is provided on the inner side of the hollow annular shape of the second end face;

[0008] The milling die is used for milling the inner wall of the side of a thin-walled part. The milling die is provided with a guard plate surrounding and fitting the side of the thin-walled part in a circumferential direction.

[0009] The turning die is used for turning the thin-walled end face of a thin-walled part provided with an annular groove. The turning die is provided with an external support structure for pressing the outside of the hollow annular end face of the thin-walled part and an internal support structure for supporting the inside of the central annular end face of the thin-walled part. The external support structure and the internal support structure enable the thin-walled part to remain stable when machining the annular groove.

[0010] Preferably, the turning die 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 die.

[0011] Preferably, the turning mold also includes: a second pressure plate, a second bottom fixing piece; one end of the external support structure is fixedly connected to the second bottom fixing piece, and the other end is press-fitted to the outer side surface of the second pressure plate; the inner side surface of the second pressure plate is press-fitted to the outer side of the second end surface.

[0012] Preferably, the second end surface partially overlaps with the pressing area of ​​the second pressing plate, and the annular center edge of the second end surface is provided with an area which is not blocked by the second pressing plate and is used for processing the annular groove.

[0013] Preferably, the external support structure is provided with a connecting pressure plate, a second pull rod and an external support rod; the connecting pressure plate is provided with a through hole; the second pull rod corresponds to the through hole one by one, one end of the second pull rod passes through the through hole and is fixedly connected to the connecting pressure plate, and the other end is fixedly connected to the second bottom fixing member; a group of side surfaces penetrated by the through hole are arranged parallel to the second pressure plate, and one side surface in the group of side surfaces is pressed and abutted against the outer edge of the second pressure plate.

[0014] Preferably, the external support structure is further provided with an external support rod; one end of the external support rod is fixedly connected to the connecting pressure plate, and the other end of the external support rod is fixedly connected to the second bottom fixing member, and is arranged away from the thin-walled part relative to the second pull rod.

[0015] Preferably, one side of the internal support structure is press-fitted and connected to the inner side of the second end surface, and the other side is fixedly connected to the second bottom fixing piece.

[0016] Preferably, the milling die 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 milling die.

[0017] Preferably, one end of the milling mold is provided with a first pressure plate pressed and connected to the first end surface, and the other end is provided with a first bottom fixing piece pressed and connected to the second end surface; the milling mold is also provided with a first pull rod; the circumferential outer edge of the first pressure plate is fixedly connected to the circumferential outer edge of the first bottom fixing piece through the first pull rod.

[0018] The invention discloses a processing method for a thin-walled part with an annular groove on the thin-wall end face, using the processing mold.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] (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 a milling process and a lathe 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 lathe processing mold to fix the second end face, thereby ensuring the dimensional accuracy of structures such as the side milling processing window.

[0021] (2) The present invention provides 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.

[0022] (3) The present invention can achieve stable pressing and fixing of the edges and 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 turning 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.

[0023] (4) 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 thin-walled parts while greatly reducing the adverse effects of vibration on processing accuracy during side processing; and improves the defects of the prior art that the side of thin-walled parts is prone to vibration and poor processing accuracy when processed from the inside to the outside.

[0024] (5) 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 part blank, so that when the milling tool processes the first groove, the guard plate provides circumferential support force for the side surface, and the support force is opposite to the force direction of the milling tool, thereby making the thin-walled part 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 applied by 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 part blank caused by local stress concentration; therefore, 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.

[0025] (6) 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 part 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.

[0026] (7) 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.

[0027] (8) The present invention provides a positioning block on the inner side of the cast thin-walled part 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 while meeting the accuracy requirements; and further uses the positioning block and the rotation axis centerline to correct the position and determine the processing reference positioning line; and further uses the reference hole on the end face of the processing reference positioning line as the transmission medium of the original reference, thereby ensuring the continuation of the reference and improving the processing accuracy.

[0028] (9) The present invention uses laser scanning imaging technology to preliminarily determine the wall thickness of each section of the casting, determine the correction position of the rotation axis, and adjust the processing reference line based on the corrected axis to coordinate the wall thickness of each processing part, so as to make the wall thickness of the part 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, it greatly reduces the workload of machine tool alignment and zeroing in subsequent processes.

[0029] (10) The present invention adopts zone-based processing according to different processing locations, divides the arc surface, and then plans the processing trajectory in each divided area to process each window one by one, instead of fixing the thin-walled part blank and controlling the tool movement, thereby reducing the tool movement displacement and avoiding processing chatter caused by excessive tool overhang, thereby ensuring processing accuracy and improving processing efficiency.

[0030] 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

[0031] 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.

[0032] Figure 1 A 45° top view schematic diagram of a large magnesium alloy thin-walled part having a groove on the thin-wall end surface in one embodiment of the present invention;

[0033] Figure 2 A schematic diagram of a large magnesium alloy thin-walled part with a groove on the thin-wall end surface in a 45° bottom view according to an embodiment of the present invention;

[0034] Figure 3 A 45° top view of a mold for milling thin-walled parts in one embodiment of the present invention;

[0035] Figure 4 A view showing the installation method of a mold for milling thin-walled parts in one embodiment of the present invention;

[0036] Figure 5 It is a cross-sectional view of the AA plane of the installation mode of the milling die for thin-walled parts in one embodiment of the present invention;

[0037] Figure 6 A view showing the installation method of a thin-walled parts turning mold in one embodiment of the present invention;

[0038] Figure 7 It is a BB-plane cross-sectional view of a thin-walled parts turning die installation view in one embodiment of the present invention;

[0039] Figure 8 A schematic diagram of a thin-walled parts turning method in one embodiment of the present invention;

[0040] Fig. 9A schematic diagram of a milling method for thin-walled parts in one embodiment of the present invention;

[0041] Fig.10 The present invention is a flowchart of a method for processing a large magnesium alloy thin-walled part having an annular groove on its thin-wall end face in one embodiment of the present invention.

[0042] Reference numerals:

[0043] 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 piece 203; first pull rod 204; connecting structure 205; second through hole 2021; first through hole 2022; external support structure 301; second bottom fixing piece 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; rotary table 4; three-jaw clamp 5; machine tool working platform 6; processing tool 7. DETAILED DESCRIPTION

[0044] 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.

[0045] 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.

[0046] The present invention discloses a thin-walled part with a groove on the end surface, such as Figure 1 and Figure 2 As 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.

[0047] 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.

[0048] It should be noted that the thin-walled part 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 for further processing to obtain the specified shape and accuracy.

[0049] It should be noted that Figure 2 The middle annular groove 1031 is obtained by fixing the thin-walled part blank with a turning die and then machining the second end surface 103 with a turning tool.

[0050] A plurality of positioning blocks 1012 are disposed on the side surface 101 of the thin-walled part, and at least one group of positioning blocks 1012 is symmetrically disposed relative to the axis center of the thin-walled part.

[0051] It should be noted that the side 101 of the part blank 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 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.

[0052] Specifically, two positioning blocks symmetrically arranged relative to the axis of the thin-walled part are used to construct the baseline of the thin-walled part: the center line of a group of positioning blocks 1012 symmetrically arranged is used as the processing baseline, and the initial position is when the processing baseline is placed vertically; by determining the angle between the center of the window 1011 and the line connecting the axis of the part and the processing baseline, the angle α that the part blank and the rotating platform connected to it need to rotate when the window 1011 is rotated to the processing baseline position is determined; based on the α of the adjacent window 1011, the rotation angle of the part blank and the rotating platform connected to it relative to the initial position when processing the adjacent window 1011 is determined.

[0053] 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 .

[0054] During implementation, the first groove 1013 is obtained by machining the side surface 101 from the outside to the inside using a milling tool.

[0055] The thin-walled part 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 part is 1:200-1000.

[0056] 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.

[0057] Specifically, the thin-walled parts can be made of any one of carbon steel, stainless steel, titanium alloy, aluminum alloy, and magnesium alloy.

[0058] On the one hand, the present invention discloses a processing die for a magnesium alloy thin-walled part having an annular groove on the end surface, such as Figure 3 and Figure 6 As shown, it includes milling molds and turning molds.

[0059] Regarding the milling mold, the milling mold is used for processing the inner wall of the side of the thin-walled part, and is fixedly connected to the first end face 102 and the second end face 103 of the thin-walled part, so that the thin-walled part is fixed to the milling mold.

[0060] Specifically, 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.

[0061] Specifically, the first pressing plate 201 is a hollow annular structure, and the milling tool enters the inside of the thin-walled part from the first end surface 102 to perform milling or the outside of the thin-walled part.

[0062] At the same time, the milling mold is also provided with a first pull rod 204; the circumferential outer edge of the first pressure plate 201 is fixedly connected to the circumferential outer edge of the first bottom fixing member 203 through the first pull rod 204, and the first bottom fixing member 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 thin-walled parts on the machine tool platform.

[0063] 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 can limit the deformation or vibration of the thin-walled part radially outward.

[0064] 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.

[0065] 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 thin-walled parts while greatly reducing the adverse effects of vibration on processing accuracy during side processing; the defects of the prior art in which the side processing of thin-walled parts is prone to vibration and poor processing accuracy are improved.

[0066] Specifically, Figure 4 , Figure 5 As shown, the first end face 102 of the thin-walled part is press-fitted with the first pressure plate 201; the second end face 103 is press-fitted with the first bottom fixing piece 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 piece 203; the first pull rod 204 is arranged along the circumferential edges of the first pressure plate 201 and the first bottom fixing piece 203, and passes through the first through hole 2022, so that the guard plate 202 is radially fixed and circumferentially press-fitted 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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 part 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.

[0071] In order to realize the processing of the first groove 1013 on the side surface 101, the height of the guard plate 202 is lower than the height of the thin-walled part blank.

[0072] 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 .

[0073] Preferably, the wall thickness of the guard plate 202 is greater than the wall thickness of the thin-walled part blank.

[0074] 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 part blank, which improves the rigidity of the side of the thin-walled part blank. When the milling tool processes the first groove 1013, the guard plate 202 provides a circumferential support force for the side 101. The support force is opposite to the force direction of the milling tool, thereby stabilizing the thin-walled part blank and preventing it from vibrating or deforming from the outside to the inside.

[0075] On the one hand, the side surface 101 is circularly arched in the radial direction, which can effectively disperse the force applied by the milling tool; on the other hand, the guard plate 202 provides circumferential support for the side surface 101, so that the guard plate 202 applies force evenly at each contact point with the side surface 101, thereby preventing deformation of the side surface of the thin-walled part blank caused by local stress concentration in the area rotated 90 degrees relative to the force application point of the milling tool.

[0076] Compared with the prior art, the guard plate 202 is arranged to surround and fit the side of the thin-walled part blank, which can provide support force in two radial directions when the side of the thin-walled part blank is milled, thereby reducing vibration and deformation in two radial directions.

[0077] Specifically, the first pull rod is detachably fixedly connected to the first pressing plate and the first bottom fixing piece.

[0078] 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.

[0079] Preferably, the first pull rod is symmetrically arranged relative to the axis center of the thin-walled part, providing uniform pressure for the thin-walled part in the radial direction.

[0080] Specifically, regarding the turning mold, the turning mold is used for end surface processing with an annular groove, and is fixedly connected to the first end surface and the second end surface of the thin-walled part, so that the thin-walled part is fixed to the turning mold.

[0081] Specifically, Figure 6 , Figure 7As shown, the turning mold also 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 parts through the second pressing plate 307.

[0082] 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.

[0083] 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 .

[0084] 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 .

[0085] 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.

[0086] 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 part 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 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 with a turning tool, thereby improving machining accuracy.

[0087] Specifically, in order to achieve the pressing and fixing of thin-walled parts during turning, such as Figure 7As 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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 parts relative to the second pull rod 3013.

[0092] 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 face 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.

[0093] 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.

[0094] 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.

[0095] On the other hand, the present invention provides a method for processing a large magnesium alloy thin-walled part having an annular groove on the end surface, using the processing mold of the magnesium alloy thin-walled part having an annular groove on the end surface, such as Fig.10 As shown, the following steps are included:

[0096] Step 1: Connect the center of the positioning block that is symmetrical relative to the axis center as the reference positioning line of the hollow annular end face, obtain the fitting image of the thin-walled part blank based on laser scanning fitting imaging, and correct the reference positioning line based on the fitting image of the thin-walled part blank; the thin-walled part 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.

[0097] Specifically, the laser scanning fitting imaging analysis software is used to synthesize the fitting image of the thin-walled part 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 part blank, the deviation of the fitting image of the thin-walled part blank and its theoretical image in each radial section is obtained; and the deviation of each radial section is judged:

[0098] If the deviation of each radial section is less than or equal to the first threshold value δ1, no adjustment is made and the reference positioning line is corrected;

[0099] If the deviation of each radial section is greater than the first threshold value δ1, adjust the position of the centerline of the theoretical image of the thin-walled part blank until the deviation of each radial section is less than or equal to the first threshold value δ1, and record the position change value △(x, y, z) of the centerline in the spatial coordinate system; in the same spatial coordinate system, change the centerline of the part blank according to △(x, y, z) to obtain the centerline coordinates of the corrected part blank; connect the center of the positioning block and the centerline of the corrected part blank in the radial plane, and use the connecting line between the two as the corrected reference positioning line.

[0100] During implementation, the thin-walled part blank is a hollow thin-walled part 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.

[0101] During implementation, the positioning block and the thin-walled part blank are cast in a mold and can be a structure with a regular shape that is easy to find the center, such as a cuboid; multiple groups of positioning blocks can be provided, and each pair is symmetrical relative to the axis center.

[0102] It should be noted that the setting accuracy of the positioning block on the thin-walled part 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 part blank, so that the starting processing position of the thin-walled part blank is close to the processing area.

[0103] It should be noted that the thin-walled parts blanks obtained by casting have uneven wall thickness on the side, which is not the ideal uniform wall thickness state; if they are processed according to the original design axis, products with uneven wall thickness will inevitably be obtained; 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 parts blank to obtain products with uniform wall thickness.

[0104] 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 radial plane deviation is relatively minimum can be screened out, and 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, and the connecting line of the two is used as the corrected reference positioning line to complete the correction of the reference positioning line.

[0105] Step 2: Perform vertical lathe processing on the two end faces and the outer circle of the side of the thin-walled part blank after the reference positioning line correction; the vertical lathe processing leaves an allowance.

[0106] Specifically, a three-jaw clamp is used to fix the thin-walled part blank from the inside, the free end face of the thin-walled part 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 side outer circle of the thin-walled part blank from the hollow annular end face to the free end face.

[0107] When implementing, Figure 8 As shown, the part blank is fixed on the rotary table 4 by a three-jaw clamp 5 to realize radial rotation around the machine tool working platform 6, and the processing tool 7 completes the outer circle processing of the side surface 101, the second end surface 103 and the first end surface 102 of the thin-walled part; at this time, the machine tool working platform 6 is a vertical lathe working platform, and the processing tool 7 is a vertical lathe processing tool.

[0108] 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.

[0109] 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.

[0110] 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 turning around 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.

[0111] Step 3: Based on the corrected reference positioning line, the side of the thin-walled part blank that has completed vertical lathe processing is processed by a milling machine. The milling mold is provided with a guard plate that is circumferentially fitted and fixed to the outer side of the side of the thin-walled part blank; the milling machine processing leaves a margin, and two reference holes are dispersedly set in the non-processing area of ​​the outer edge of the free end face of the thin-walled part blank relative to the axis line; the center point of the reference hole is collinear with the corrected reference positioning line.

[0112] Specifically, the above-mentioned milling mold for processing the inner wall of the side of the thin-walled part is used to fix the thin-walled part blank from the outside, the hollow annular end face of the thin-walled part blank is fixed to the rotating worktable, and the free end face is set near the milling tool end; the milling tool mills the side of the thin-walled part blank from the inner side to the outer side.

[0113] When implementing, Fig. 9As shown, the part blank 1 is fixed on the rotating worktable 4 by means of a milling processing mold to realize radial rotation around the machine tool working platform 6. One end of the milling processing mold is provided with a first pressing plate 201 which is pressed and connected with the first end face 102, and the other end is provided with a first bottom fixing piece 203 which is pressed and connected with the second end face 103; the processing tool 7 penetrates into the interior of the thin-walled part to complete the processing of the side surface 101 from the inside to the outside, and processes the window 1011 to remove the excess; at this time, the machine tool working platform 6 is a milling machine working platform, and the processing tool 7 is a milling processing tool.

[0114] It should be noted that the side of the part blank has multiple windows, and the part blank needs to be rotated to process the windows one by one. Therefore, it is necessary to determine the rotation angle of the part blank and the rotating platform connected to it when processing adjacent windows.

[0115] Specifically, obtain the connection line between the center of the side window of the part blank and the axis line, and further obtain the angle between the connection line between the window center and the axis line and the corrected reference positioning line; use the angle to calculate the rotation angle of the part blank and the rotating platform connected to it when processing adjacent windows.

[0116] During implementation, the processing reference line is placed vertically as the initial position; by determining the angle between the center of the window and the line connecting the axis of the part blank and the processing reference line, it is determined that when the window is rotated to the processing reference line position, the angle α that the part blank and the rotating platform connected to it need to rotate is clear; based on the α of the adjacent window, the rotation angle of the part blank and the rotating platform connected to it relative to the initial position is determined when processing the adjacent window.

[0117] Specifically, on the corrected reference positioning line, two reference holes (not shown in the figure) are dispersedly arranged in the non-processing area of ​​the outer edge of the hollow annular end face of the thin-walled part blank relative to the axis line.

[0118] It should be noted that the milling machine processing with allowance mentioned in this article means that the milling machine processing has not been processed to the size of the formed component, and there is an allowance for further milling machine processing.

[0119] It should be noted that the positioning block is removed after the milling machine processing, and the corrected reference positioning line needs to be further transferred, so the reference hole is set as a transfer medium for the reference positioning line.

[0120] Preferably, the reference hole is a target processing hole for forming a thin-walled part.

[0121] Step 4: Stabilize the thin-walled part blank after milling.

[0122] Specifically, the thin-walled part blank processed by the milling machine is subjected to a heating-air cooling-reheating-furnace cooling treatment to remove residual stress in the turning and milling processes.

[0123] Step 5: Perform a second vertical lathe process on the two end faces and the outer circle of the side of the thin-walled part blank that has completed the stabilization treatment, and the second vertical lathe process leaves an allowance.

[0124] Specifically, a three-jaw clamp is used to fix the thin-walled part blank from the inside, the free end face of the thin-walled part blank is fixed to the rotating worktable, and the hollow annular end face is set close to the turning tool end; the turning tool turns the two end faces and the side outer circle of the thin-walled part blank from the hollow annular end face to the free end face.

[0125] like Figure 8 As shown, the part blank 1 is fixed on the rotary table 4 by a three-jaw clamp 5 to realize radial rotation around the machine tool working platform 6, and the processing tool 7 completes the external cylindrical processing of the side surface 101, the second end surface 103 and the first end surface 102 of the thin-walled part; at this time, the machine tool working platform 6 is a vertical lathe working platform, and the processing tool 7 is a vertical lathe processing tool.

[0126] Step 6: Based on the reference hole, the thin-walled part blank that has completed the second vertical lathe processing is subjected to a second milling machine processing. The second milling machine processing mold is provided with a guard plate that is circumferentially fitted and fixed to the outer side of the side of the thin-walled part blank; the second milling machine processing leaves a margin.

[0127] Specifically, the above-mentioned milling mold for processing the inner wall of the side of the thin-walled part is used to fix the thin-walled part blank from the outside, the hollow annular end face of the thin-walled part blank is fixed to the rotating worktable, and the free end face is set near the milling tool end; the milling tool mills the side of the thin-walled part blank from the inner side to the outer side.

[0128] When implementing, Fig. 9 As shown, a milling die is used to fix the part blank on the rotary table 4 to realize radial rotation around the machine tool work platform 6. One end of the milling die is provided with a first pressing plate 201 which is pressed and connected with the first end face 102, and the other end is provided with a first bottom fixing piece 203 which is pressed and connected with the second end face 103; the processing tool 7 penetrates into the interior of the thin-walled part to complete the processing of the side surface 101 from the inside to the outside, and the window 1011 is processed to remove the excess; at this time, the machine tool work platform 6 is a milling machine work platform, and the processing tool 7 is a milling tool.

[0129] Specifically, the straight line connecting the center points of the reference holes is used as the reference positioning line for the second milling machine processing.

[0130] During implementation, the line connecting the center points of the reference holes is marked with a marking device and used as the reference positioning line for the second milling machine processing; the line connecting the center of the side window of the part blank and the axis line is obtained, and the angle between the line connecting the center of the window and the axis line and the reference positioning line for the second milling machine processing is further obtained; the reference positioning line is placed vertically as the initial position; by determining the angle between the center of the window and the line connecting the part axis and the processing reference line, the angle α that the part blank and the rotating platform connected to it need to rotate when the window is rotated to the processing reference line position is determined; based on the α of the adjacent windows, the rotation angle of the part blank and the rotating platform connected to it relative to the initial position when processing the adjacent windows is determined.

[0131] Step 7: Based on the reference point and the lathe processing mold for machining the thin-walled end face with an annular groove, the thin-walled part blank that has completed the second milling machine processing is subjected to a third vertical lathe processing to machine the outer circle of the thin-walled part blank to the target size and obtain the annular groove of the center annular end face.

[0132] Specifically, a turning mold for machining thin-walled end faces with annular grooves is used to fix the thin-walled part blank from the inside and outside, the free end face of the thin-walled part blank is fixed to a rotating worktable, and the hollow annular end face is set close to the turning tool end; the turning tool turns the two end faces and the outer circle of the side of the thin-walled part blank from the hollow annular end face to the free end face.

[0133] When implementing, Figure 6 , Figure 7 As shown, the turning mold includes: a second pressing plate 307, an external supporting structure 301, an internal supporting structure 305, and 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 pressed and connected to the outer side surface of the second pressing plate 307; the inner side surface of the second pressing plate 307 is pressed and connected to the outer side of the second end surface 103, and the external supporting structure 301 and the second pressing plate 307 provide a tightening and pressing force between the second pressing plate 307 and the second bottom fixing piece 303 for the second end surface 103 and the thin-walled part; one side of the internal supporting structure 305 is pressed and connected to the inner side of the second end surface 103, and the other side is fixedly connected to the second bottom fixing piece 303, and the internal supporting structure 305 and the second bottom fixing piece 303 provide a supporting force from the inside to the outside of the thin-walled part for the second end surface 103.

[0134] During implementation, the turning tool processes the central inner edge of the hollow annular end face from shallow to deep to obtain an annular groove of the central annular end face.

[0135] Step 8: Based on the reference hole, the thin-walled part blank that has completed the third vertical lathe processing is subjected to a third milling machine processing. The milling mold used for the third milling machine processing is provided with a guard plate that is circumferentially fitted and fixed to the outer side of the side of the thin-walled part blank; the milling machine processing leaves a margin; the third milling machine processing processes the window on the side of the thin-walled part blank to the target size.

[0136] Specifically, the above-mentioned milling mold for processing the inner wall of the side of the thin-walled part is used to fix the thin-walled part blank from the outside, the hollow annular end face of the thin-walled part blank is fixed to the rotating worktable, and the free end face is set near the milling tool end; the milling tool mills the side of the thin-walled part blank from the inner side to the outer side.

[0137] When implementing, Fig. 9 As shown, a milling die is used to fix the part blank on the rotary table 4 to realize radial rotation around the machine tool work platform 6. One end of the milling die is provided with a first pressing plate 201 which is pressed and connected with the first end face 102, and the other end is provided with a first bottom fixing piece 203 which is pressed and connected with the second end face 103; the processing tool 7 penetrates into the interior of the thin-walled part to complete the processing of the side surface 101 from the inside to the outside, and the window 1011 is processed to remove the excess; at this time, the machine tool work platform 6 is a milling machine work platform, and the processing tool 7 is a milling tool.

[0138] Specifically, the straight line connecting the center points of the reference holes is used as the reference positioning line for the third milling machine processing.

[0139] During implementation, the line connecting the center points of the reference holes is marked with a marking device and used as the reference positioning line for the third milling machine processing; the line connecting the center of the side window of the part blank and the axis line is obtained, and the angle between the line connecting the center of the window and the axis line and the reference positioning line for the third milling machine processing is further obtained; the reference positioning line is placed vertically as the initial position; by determining the angle between the center of the window and the line connecting the part axis and the processing reference line, the angle α that the part blank and the rotating platform connected to it need to rotate when the window is rotated to the processing reference line position is determined; based on the α of the adjacent windows, the rotation angle of the part blank and the rotating platform connected to it relative to the initial position when processing the adjacent windows is determined.

[0140] Specifically, Figure 3 , Figure 4 and Figure 5As shown: the milling die is fixedly connected to the first end face 102 and the second end face 103 of the thin-walled part; one end of the milling die is provided with a first pressing plate 201 which is press-fitted with the first end face 102, and the other end is provided with a first bottom fixing piece 203 which is press-fitted with the second end face 103; at the same time, the circumferential outer edge of the first pressing plate 201 and the corresponding position of 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 press-fit fixation of the thin-walled part on the machine tool platform.

[0141] The milling processing mold is provided with a guard plate 202 on the side 101 of the thin-walled part to limit the radial vibration of the thin-walled part; the guard plate 202 circumferentially surrounds the side 101 and is provided with a first through hole 2022; a first pull rod 204 is passed through the first through hole 2022, and the first pull rod 204 circumferentially arranged along the side 101 enables the guard plate 202 to circumferentially surround and fit the side 101, so as to limit the radial deformation or vibration of the thin-walled part toward the outside when the milling machine tool processes the inner wall of the side 101.

[0142] It should be noted that the milling machine tool processes the side 101 of the thin-walled part from the inside to the outside, and applies 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.

[0143] 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.

[0144] On the other hand, the present invention arranges a first pressure plate, a first bottom fixing piece, a first pull rod and a guard plate in the milling mold, thereby achieving the pressing and fixing of thin-walled parts while greatly reducing the adverse effects of vibration on processing accuracy during side processing; and improves the defects of the prior art that the sides of thin-walled parts are prone to vibration and poor processing accuracy when milling from the inside to the outside.

[0145] 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.

[0146] In addition, the present invention provides a positioning block on the inner side of the cast thin-walled part 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.

[0147] 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.

[0148] Specifically, step 1 is based on laser scanning fitting imaging to obtain a fitting image of a thin-walled part blank. The specific method is: using sensors densely distributed on the inner and outer surfaces of the thin-walled part blank as data sampling points, using laser scanning to obtain the coordinates of the sensor in the spatial coordinate system, and fitting a three-dimensional image of the thin-walled part blank according to the sensor spatial coordinate information.

[0149] Specifically, the step 1 of correcting the reference positioning line based on the fitting image of the thin-walled part blank includes:

[0150] S101: 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;

[0151] S102: If the radial cross-section deviations are less than or equal to the first threshold δ1, no adjustment is made and the reference positioning line is corrected;

[0152] If the deviation of each radial section is greater than the first threshold value δ1, adjust the position of the axis centerline of the theoretical image of the thin-walled part blank until the deviation of each radial section is less than or equal to the first threshold value δ1, and record the position change value △(x, y, z) of the axis centerline in the spatial coordinate system;

[0153] S103: constructing 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 changing the axis of the part blank according to △(x, y, z) in the coordinate system to obtain the axis coordinate of the corrected part blank;

[0154] S104: In the radial plane where the positioning block center of the part blank is located, connect the center of any positioning block and the axis line of the corrected part blank, and use the connecting line of the two as the corrected reference positioning line to complete the reference positioning line correction.

[0155] Preferably, the first threshold δ1 is 0.02 mm.

[0156] It should be noted that the determination of the first threshold δ1 is related to the accuracy of the dial indicator itself. The first threshold δ1 is less than 0.02 mm, which exceeds the accuracy range of the dial indicator.

[0157] Specifically, the vertical lathe processing described in step 2 includes the following steps:

[0158] S201: Select 1 / 4 to 1 / 2 of the machining amount of the vertical lathe for the fixed thin-walled part blank, perform trial machining, and obtain a trial machining blank sample;

[0159] S202: Detecting the eccentricity of the test blank sample rotating around the axis of the corrected part blank;

[0160] S203: judging the eccentricity;

[0161] If the eccentricity is less than the second threshold value δ2, turning is performed;

[0162] If the eccentricity is greater than the second threshold value δ2, then steps S101-S104 are repeated to correct the axis line of the part blank again until the eccentricity is less than the second threshold value δ2.

[0163] Specifically, the eccentricity described in S202 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.

[0164] 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.

[0165] Optionally, the second threshold δ2 is set to 0.02 mm.

[0166] It should be noted that the determination of the second threshold value δ2 is related to the accuracy of the dial indicator itself. The second threshold value δ2 is less than 0.02 mm, which exceeds the accuracy range of the dial indicator.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] Specifically, the machining amount of the vertical lathe machining in step 2 is 2 to 4 mm.

[0172] Preferably, the machining amount of the vertical lathe machining in step 2 is 3 mm.

[0173] Specifically, the milling machine processing described in step 3 is performed by obtaining the angle between the center of the side window of the part blank, the axis line connection line and the corrected reference positioning line, and using the angle to calculate the rotation angle of the part blank and the rotating platform connected thereto when processing adjacent windows, specifically including:

[0174] S301: Connect the center of the window with the axis of the part blank in the radial plane, and obtain the angle α between the connection line and the processing reference line through the angle measuring device. Based on the adjacent order of the windows, they are numbered as the first window, ..., the nth window, and the corresponding angles α are numbered as α1, ..., α n ;

[0175] S302: Calculate the difference △α between any adjacent windows and the processing reference line as the rotation angle of the part blank and the rotating platform connected thereto when the adjacent windows are processed; wherein △α satisfies: △α=α k -α k-1 , k≤n; k represents the window number, α k It is the angle between the center of the kth window in the radial plane, the line connecting the axis of the part blank and the machining reference line.

[0176] Specifically, when adjacent windows are processed, the rotation angle of the part blank and the rotating platform connected thereto is adjusted by the angle scale provided on the rotating platform.

[0177] Specifically, the reference hole in step 3 is obtained by using a machine tool hole opening device, and a positioning pin is inserted to correct the position of the reference hole, including:

[0178] S311: Setting a first coordinate axis in a direction perpendicular to the horizontal plane, taking the rotation axis of the rotating platform of the machine tool as the second coordinate axis, and setting a third coordinate axis in a direction perpendicular to the first coordinate axis and the second coordinate axis in the horizontal plane to construct a spatial coordinate system;

[0179] S312: Selecting a positioning pin of one of the reference holes as a first positioning pin, setting a dial indicator on the machine tool spindle to contact the highest point of the side of the first positioning pin, and recording the dial indicator reading;

[0180] S313: Select the positioning pin of another reference hole as the second positioning pin, rotate it 180 degrees using the scale of the machine tool rotating platform, keep the coordinates of the machine tool spindle on the first coordinate axis and the second coordinate axis unchanged, and make contact with the highest point on the side of the second positioning pin, and record the dial indicator reading;

[0181] S314: Calibrate the reference hole based on the two dial indicator readings;

[0182] If the difference between the two dial gauge readings is less than the third threshold value δ3, it is judged that the reference hole setting meets the requirements;

[0183] If the difference between the two dial indicator readings is greater than the third threshold value δ3, the original reference hole is enlarged based on the corrected reference positioning line, and matching positioning pins are selected to repeat S312-S313 until the difference between the two dial indicator readings is less than the third threshold value δ3.

[0184] Specifically, the accuracy of the reference hole setting is evaluated by the change in the dial indicator pointer reading η, and η satisfies: η=S max -S min , where S max The maximum value of the dial indicator pointer reading between two dial indicator readings, S min It is the minimum value of the dial indicator pointer indication of two dial indicator readings.

[0185] Optionally, the third threshold δ3 is set to 0.02 mm.

[0186] It should be noted that the determination of the third threshold value δ3 is related to the accuracy of the dial indicator itself. The third threshold value δ3 < 0.02 mm exceeds the accuracy range of the dial indicator.

[0187] Specifically, expanding the hole on the original reference hole based on the corrected reference positioning line includes: repositioning the center of the expanded reference hole on the corrected reference positioning line and then expanding the hole; the expanded diameter of the reference hole should be larger than the original reference hole, and the expanded reference hole completely covers the original reference hole area, thereby eliminating the error caused by the deviation in the position setting of the original reference hole.

[0188] It should be noted that the distance between the center of the reference hole and the corrected reference positioning line can be adjusted according to actual needs. Therefore, when reading the dial indicator in steps S312-S313, there is no need to read the coordinates of the third coordinate axis parallel to the corrected reference positioning line.

[0189] Specifically, the processing amount of the milling machine in step 3 is 1mm to 5mm.

[0190] Preferably, the processing amount of the milling machine in step 3 is 2mm to 3mm.

[0191] Specifically, the determination of the highest point of the pin side in S312 and S313 includes:

[0192] S321: Setting a first coordinate axis in a direction perpendicular to the horizontal plane, taking the rotation axis of the machine tool rotating platform as the second coordinate axis, setting a third coordinate axis in a direction perpendicular to the first coordinate axis and the second coordinate axis in the horizontal plane, and constructing a spatial coordinate system with the center of the machine tool rotating platform as the origin;

[0193] S322: Select a locating pin of one of the reference holes and insert it into a matching locating pin. Set a dial indicator on the machine tool spindle to contact the top area of ​​one end of the side of the locating pin and indicate a number. Keep the coordinates of the first coordinate axis and the second coordinate axis of the machine tool spindle unchanged. Move the machine tool spindle parallel to the third coordinate axis and keep the percentage indication non-zero. Record the spatial coordinates when the percentage indication is the minimum as the coordinates of the highest point on one end of the side of the locating pin.

[0194] S323: The coordinates of the highest point at the other end of the side of the positioning pin are obtained in the same way, and the coordinates of the highest points at both ends are compared, and the one with the larger value of the first coordinate axis coordinate is taken as the coordinates of the highest point on the side of the pin.

[0195] It should be noted that the pins are generally selected from cylinders with smooth and flat sides. Due to the limitation of the accuracy of drilling the reference hole, the flatness of the hole is poor. The positioning pins may be non-level after installation and cannot be further used to calibrate the reference hole.

[0196] Furthermore, in order to correct the longitudinal flatness of the reference hole opening, the flatness correction of the reference hole opening is also included between S311 and S312:

[0197] S324: Compare the coordinates of the highest points (x1, y1, z1) and (x2, y2, z2) at both ends obtained in steps S322 and S323, and obtain the coordinate differences △x, △y, △z of each coordinate axis; wherein △x=|x1-x2|, △y=|y1-y2|, △z=|z1-z2|;

[0198] If △x, △y, and △z are all less than the fourth threshold δ4, it is judged that the opening flatness of the reference hole meets the requirement;

[0199] If any value among △x, △y, △z is greater than the fourth threshold value δ4, the original reference hole is enlarged based on the corrected reference positioning line, and matching positioning pins are selected to repeat S322-S323 until △x, △y, △z are all less than the fourth threshold value δ4.

[0200] Optionally, the fourth threshold δ4 is related to the machining accuracy of the machine tool.

[0201] Compared with the existing technology, the method adopts zone-based processing according to different processing parts, divides the arc surface, and then plans the processing trajectory in each divided area to process each window one by one, instead of fixing the thin-walled part blank and controlling the tool movement, which reduces the tool movement displacement and avoids the processing vibration caused by the excessive overhang of the tool, thereby ensuring the processing accuracy and improving the processing efficiency.

[0202] Specifically, the stabilization process in step 4 further reduces the residual stress in the pre-processing process, including the following steps:

[0203] S401: Heat treatment at 120±10℃ for 2h~6h, then air-cooling to room temperature;

[0204] S402: Heat treatment at 120±10℃ for 2h~6h, then cooling to room temperature in the furnace.

[0205] The thermal stress continuously generated in the process of positive temperature-air cooling-positive temperature-furnace cooling is superimposed on the original residual stress, exceeding the yield strength of the material and causing plastic deformation, thereby reducing the original residual stress and further improving the plasticity and machinability of the cylindrical material.

[0206] Specifically, step S401 uses air cooling to quickly superimpose the thermal stress of the outer surface and the original residual stress, resulting in plastic deformation; step S402 uses furnace cooling to slowly cool down the temperature, which can reduce the thermal stress on the outer and inner surfaces of the part blank caused by air cooling; overall, the effect of reducing the stress caused by rough machining is achieved.

[0207] It should be noted that the first vertical turning and milling machine processing are rough processing processes. Due to the large removal allowance, the accumulated stress in the processing process is large, so stabilization treatment is required to remove the accumulated stress; the second vertical turning processing, the second milling machine processing and the third vertical turning processing and the third milling machine processing have smaller removal allowances and the processed blanks are thinner, so it is not easy to accumulate stress.

[0208] Specifically, in the second turning process described in step 5, in order to meet the requirements of magnesium alloy processing, the feed rate of the part blank is 0.4mm / r~0.6mm / r; 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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] Specifically, the second vertical lathe processing in step 5 leaves a margin, and the outer circle is not processed to the forming size. The processing amount of the second vertical lathe processing is 1 to 3 mm.

[0213] Preferably, the machining amount of the second vertical lathe machining in step 5 is 2 mm.

[0214] Specifically, the second milling machine processing described in step 6 is performed by obtaining the angle between the center of the side window of the part blank, the axis line connection line and the corrected reference positioning line, and using the angle to calculate the rotation angle of the part blank and the rotating platform connected thereto when processing adjacent windows, specifically including:

[0215] S601: Connect the center of the window with the axis of the part blank in the radial plane, and obtain the angle α between the connection line and the processing reference line through the angle measuring device. Based on the adjacent order of the windows, they are numbered as the first window, ..., the nth window, and the corresponding angles α are numbered as α1, ..., α n ;

[0216] S602: Calculate the difference △α between any adjacent windows and the processing reference line as the rotation angle of the part blank and the rotating platform connected thereto when the adjacent windows are processed; wherein △α satisfies: △α=αk -α k-1 , k≤n.

[0217] Specifically, when adjacent windows are processed, the rotation angle of the part blank and the rotating platform connected thereto is adjusted by the angle scale provided on the rotating platform.

[0218] During implementation, the angle scale of the rotating platform during the processing of the previous window is recorded, and the angle scale of the rotating platform is rotated by Δα so that the window to be processed is at the processing position of the previous window.

[0219] The third vertical lathe processing described in step 7 is performed to process the outer circle of the thin-walled part blank to the target size and obtain the annular groove of the center annular end face, including:

[0220] S701: Using the above-mentioned lathe processing mold for machining the thin-walled end surface with an annular groove, fix the free end surface of the thin-walled part blank on the rotating worktable, and set the hollow annular end surface close to the lathe processing tool end;

[0221] S702: Use a turning tool to machine the outer circle of the side of the thin-walled part blank to the target size;

[0222] S703: Use a turning tool to process the inner edge of the central annular end face of the thin-walled part blank to obtain an annular groove.

[0223] Specifically, the step S701 of fixing the free end surface of the thin-walled part blank on the rotating worktable includes:

[0224] S7011: 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;

[0225] S7012: 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.

[0226] Compared with the prior art, the present invention arranges an internal supporting structure and an external supporting structure in the turning mold, and provides a tightening and pressing force between the second pressing plate and the second bottom fixing member for the thin-walled part through the second pressing plate. The internal supporting 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 pressing plate, thereby fixing the second end face and reducing the deformation and vibration of the second end face during machining with the turning tool, thereby improving the machining accuracy.

[0227] In order to meet the requirements of magnesium alloy processing, the feed rate of the part blank is 0.2mm / r~0.4mm / r during the third turning process; if it is lower than 0.2mm / r, local overheating is likely to occur, causing deformation of the magnesium alloy or even spontaneous combustion; if it is higher than 0.4mm / r, it is difficult to meet the precision requirements.

[0228] In order to improve local heat dissipation, a cooling airflow of 0.7MPa to 0.8MPa is applied during the processing of the blank parts.

[0229] 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 0.8MPa to 1.0MPa of air-cooled airflow for cooling, which increases the wind pressure, helps solve the problem of local heat dissipation, and can reduce the feed rate and improve processing accuracy and processing safety.

[0230] In order to reduce the deformation during machining, the cutting depth of the part blank is 0.2~0.5; since the thickness of the part is reduced by the third turning, the cutting depth of the part blank is less than or equal to 0.5, and at the same time, a turning mold for thin-walled end face machining with annular grooves is used to fix it to avoid deformation.

[0231] The third milling process described in step 8 processes the window on the side of the thin-walled part blank to the target size, including:

[0232] S801: using the milling die for machining the inner wall of the side of a thin-walled part, fix the hollow annular end face of the thin-walled part blank on a rotary table, and set the free end face close to the lathe tool end;

[0233] S802: Connect the center of the window with the axis of the part blank in the radial plane, and obtain the angle α between the connection line and the processing reference line through the angle measuring device. Based on the adjacent order of the windows, they are numbered as the first window, ..., the nth window, and the corresponding angles α are numbered as α1, ..., α n ;

[0234] S803: Calculate the difference △α between any adjacent windows and the processing reference line as the rotation angle of the part blank and the rotating platform connected to it when the adjacent windows are processed; where △α satisfies: △α=α k -α k-1 , k≤n.

[0235] S804: With the machining reference line in a vertical state as the initial position, the machining area of ​​the milling tool is set to be in the horizontal plane below the axis, the rotating platform is rotated by α1 degrees, so that the line connecting the first window and the axis is in the initial position, the machining plane of the first window is in the machining area of ​​the milling tool, and the first window is milled to a target size;

[0236] S805: rotating the rotating platform by α2-α1 degrees so that the processing plane of the second window is in the processing area of ​​the milling tool, and milling the second window to a target size;

[0237] S806: Rotate the rotating platform by α3-α2, ..., α n -α n-1 The degree is set so that the machining planes of the third window, ..., the nth window are in the machining area of ​​the milling tool, and the third window, ..., the nth window are milled to the target size; completing the third milling machine processing of the thin-walled part blank.

[0238] Specifically, the step S801 of fixing the free end surface of the thin-walled part blank on the rotating worktable includes:

[0239] S8011: 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;

[0240] S8012: The circumferential outer edge of the first pressing plate is fixedly connected to the corresponding position of the circumferential outer edge of the first bottom fixing member through a first pull rod, and the first bottom fixing member is fixedly connected to the machine tool platform;

[0241] S8013: The first pull rod is passed through the first through hole circumferentially arranged around the side surface, and the first pull rod circumferentially arranged along the side surface enables the guard plate to circumferentially fit the side surface.

[0242] Compared with the prior art, 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 thin-walled parts while greatly reducing the adverse effects of vibration on processing accuracy during side processing; and improves the defects of the prior art in which the side processing of thin-walled parts is prone to vibration and poor processing accuracy.

[0243] The third milling process also includes the step of using measuring equipment to detect the wall thickness at various locations on the side.

[0244] At the same time, a second through hole is radially arranged on the guard plate so that the side wall thickness can still be measured during milling, and ventilation and heat dissipation are achieved through the through hole, solving the problems of difficulty in thickness control and poor heat dissipation in the side wall processing of thin-walled parts in the prior art.

[0245] Specifically, Figure 3 , Figure 4 As shown, a plurality of second through holes 2021 are provided on the side of the guard plate 202 , and an external device detects the wall thickness of each point of the side surface 101 through the second through holes 2021 .

[0246] During implementation, ultrasonic, laser or X-ray equipment is used to detect the wall thickness of each point on the side surface 101.

[0247] The processing method of the magnesium alloy thin-walled parts also includes a step of checking the crack damage of the thin-walled parts after step 8. Specifically, the detection is performed using the GJ / B 1187A-2001 "Radiographic Detection" method, and the acceptance standard uses the Class I casting requirements in QJ20708 "Rare Earth Heat-Resistant Cast Magnesium Alloys and Casting Specifications" for acceptance; the selection method is X-ray fluorescence flaw detection.

[0248] The processing method of the magnesium alloy thin-walled parts comprises, after the step of inspecting the thin-walled parts for crack damage, a micro-arc oxidation treatment step on the surface of the magnesium alloy thin-walled parts. Specifically, a high-voltage electric arc is used to generate a heat-resistant and hard magnesium oxide layer on the surface of the magnesium alloy, thereby improving the oxidation resistance, surface hardness and wear resistance of the magnesium alloy.

[0249] 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. A processing die for a thin-walled part with an annular groove on the end surface, characterized in that: Including milling molds and turning molds; The thin-walled part comprises: a first end face, a second end face and a side surface connecting the first end face and the second end face; the first end face is an unobstructed free end face, and the second end face is a hollow annular end face; an annular groove is provided inside the hollow annular shape of the second end face; The milling die is used for milling the inner wall of the side of a thin-walled part. The milling die is provided with a guard plate surrounding and fitting the side of the thin-walled part in a circumferential direction. The lathe processing mold is used for lathe processing of thin-walled end faces of thin-walled parts with annular grooves. The lathe processing mold is provided with an external support structure for pressing the outside of the hollow annular end face of the thin-walled part and an internal support structure for supporting the inside of the central annular end face of the thin-walled part. The external support structure and the internal support structure enable the thin-walled part to remain stable when processing the annular grooves. The lathe processing 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 lathe processing mold; The lathe processing mold further includes: a second pressing plate and a second bottom fixing piece; one end of the external support structure is fixedly connected to the second bottom fixing piece, 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; The external support structure is provided with a connecting plate, a second pull rod and an external support rod; the connecting plate is provided with a through hole; the second pull rod corresponds to the through hole one by one, one end of the second pull rod passes through the through hole and is fixedly connected to the connecting plate, and the other end is fixedly connected to the second bottom fixing member; a group of side surfaces passed through by the through hole are arranged parallel to the second plate, and one side surface of the group of side surfaces is pressed and abutted against the outer edge of the second plate; One end of the external support rod is fixedly connected to the connecting plate, and the other end is fixedly connected to the second bottom fixing member, and is arranged away from the thin-walled part relative to the second pull rod; One side of the internal support structure is press-fitted and connected to the inner side of the second end surface, and the other side is fixedly connected to the second bottom fixing member; The milling die 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 milling die; One end of the milling mold is provided with a first pressure plate pressed and connected to the first end surface, and the other end is provided with a first bottom fixing piece pressed and connected to the second end surface; the milling mold is also provided with a first pull rod; the circumferential outer edge of the first pressure plate is fixedly connected to the circumferential outer edge of the first bottom fixing piece through the first pull rod.

2. The processing mold according to claim 1, characterized in that: The second end surface partially overlaps with the pressing area of ​​the second pressing plate, and the annular center edge of the second end surface is provided with an area which is not blocked by the second pressing plate and is used for processing the annular groove.

3. A method for processing a thin-walled part with an annular groove on the end surface, characterized in that: Use the processing mold described in claim 1 or 2.

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