Machining method for large titanium alloy ultra-deep cavity thin-wall weak-rigidity complex structural part

Abstract

The invention belongs to the technical field of numerical control machining, and discloses a machining method for a large titanium alloy ultra-deep-cavity thin-wall weak-rigidity complex structural part, which comprises the following steps of: 1, fixing a die forging blank on a clamp by utilizing a process table around the die forging blank; secondly, rough machining is conducted on the die forging blank, datum holes are machined in two of the process tables, and the side wall allowance of a side groove is distributed in a stepped mode after rough machining; thirdly, the roughly machined part is subjected to heat treatment; 4, the hole position of the reference hole is detected, the hole position is compared with the theoretical hole position to analyze the deformation amount and the deformation direction of the blank, and when the deformation amount is smaller than the machining allowance, semi-finish machining is conducted; and fifthly, the semi-finished part is subjected to finish machining, and a connecting rib between the final milling process table and the part is machined.

Description

Technical Field

[0001] The invention belongs to the technical field of numerical control machining, in particular to a machining method for a large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural part. Background Art

[0002] Titanium alloy materials are widely used in the aerospace field due to their superior physical and chemical properties. However, due to their low stiffness, titanium alloy thin-walled parts are easily vibrated and deformed by the cutting force during cutting, resulting in poor surface quality and difficult to guarantee dimensions. With the continuous improvement of modern aircraft's performance requirements for long life, light weight, and high reliability, some key load-bearing parts are designed with titanium alloy materials in an integrated manner. The improvement in structural performance requirements has made the manufacturing technology of large titanium alloy structural parts a key technology in aircraft development. However, under the development trend of integration, complexity, and precision of titanium alloy structural parts, large-scale aviation titanium alloy ultra-deep cavity thin-walled structures are still a difficult problem in the field of CNC machining at home and abroad. Key technologies are still insufficient, and products are prone to processing vibration and processing deformation, which seriously affects product quality. The efficient and precise processing and manufacturing technology of ultra-deep cavity thin-walled complex structural parts still faces severe challenges. Summary of the invention

[0003] Purpose of the invention: The present invention discloses a processing method for large-scale titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural parts. This method can solve the problems of processing chatter and processing deformation that occur during CNC processing of ultra-deep cavity thin-walled weak rigidity parts, improve the continuity and processing efficiency, improve product quality, and ensure the stable processing of titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural parts. Summary of the invention:

[0005] A processing method for a large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural part, the steps are as follows:

[0006] Step 1: Fix the die forging raw material on the fixture using the process table around the die forging raw material;

[0007] Step 2: Rough-process the forging blank and process the reference holes on two of the process tables. The side wall allowance of the side groove after rough processing is distributed in a stepped manner. The two process holes are selected on the two farthest process tables as much as possible to reduce the influence of deformation on subsequent processing caused by the change of the reference hole. The side wall allowance of the side groove after rough processing is distributed in a stepped manner to ensure that there is a large enough processing allowance to ensure rigidity during the processing when finishing the deep side groove.

[0008] Step 3: Heat treat the parts after rough machining; heat treatment is a stress relief treatment. The main purpose of titanium alloy stress relief is to eliminate the residual stress of the parts after rough machining as much as possible, so that the parts can obtain better finishing conditions, and at the same time it can also reduce the deformation of the parts after finishing.

[0009] Step 4: Check the hole position of the reference hole, compare and analyze the deformation amount and deformation direction of the rough material with the theoretical hole position, and perform semi-finishing when the deformation amount is less than the machining allowance; when the deformation amount is greater than the machining allowance, consider re-stressing the part to obtain a smaller heat treatment deformation. The deformation direction data is used as a reference when establishing the machining reference and machining coordinate system for semi-finishing.

[0010] Step 5: Finish the semi-finished parts and finally mill the connecting ribs between the process table and the parts.

[0011] Furthermore, in step one, no less than five process tables are arranged on one side of the straight side or arc side of the die forging blank, no process table is arranged on the side where the side groove is located, and at least two process tables are arranged on the short side adjacent to the side groove.

[0012] Furthermore, in step 2, rough machining is performed in three stations:

[0013] The first and second stations are carried out in a three-coordinate vertical machining center, and the upper and lower surfaces of the die forging blank except the side grooves are rough-machined respectively. The second rough machining allowance range of the upper and lower webs is generally 3-5mm, and the first rough machining allowance range of the rest is generally 2-3mm;

[0014] The third workstation is carried out on a five-axis vertical-horizontal conversion machining center, using horizontal machining, and the side groove side wall allowance decreases in steps from the bottom to the opening.

[0015] Furthermore, the margin of the side groove side wall is 6-8mm at the bottom, 4-5mm in the middle, and 2-3mm at the opening. When the margin is distributed in steps, there are at least three steps, and the depth of each step is equal.

[0016] Furthermore, in step 4, during semi-finishing, when the deformation is greater than the machining allowance, it is necessary to consider re-heat treatment to obtain a smaller deformation.

[0017] Furthermore, in step four, semi-finishing is divided into two stations and carried out on a three-coordinate vertical machining center, and the upper and lower surfaces of the part except the side grooves are processed respectively; the first finishing allowance is left on the inner and outer surfaces of the surrounding side panels; the second finishing allowance is left on the upper and lower belly plate surfaces; the second finishing allowance is greater than the first finishing allowance.

[0018] Furthermore, the first finishing allowance is 0.5-1 mm; the second finishing allowance is 2-3 mm.

[0019] Furthermore, in step five, finishing is performed in three stations. The first station processes the side groove, and the processing depth increases from shallow to deep. The tool overhang used also increases in sequence according to the processing depth, and short overhang milling cutter, long overhang milling cutter and super long overhang cutter are used successively for processing;

[0020] After the side grooves are processed, a conformal array auxiliary support device is used to fix the side grooves;

[0021] The second station processes the upper surface web, rib height, and vertical rib side walls;

[0022] The third workstation processes the lower surface web, rib height, and vertical rib side walls.

[0023] Furthermore, the parameters for machining the side grooves are as follows:

[0024] The processing parameters of the bottom of the side groove side wall are: using a φ40R5L265 square shoulder milling cutter, adopting a radial priority cutting strategy, a cutting depth of 5mm, a cutting width of 1mm, a rotation speed of S=400r / min, and F=210mm / min.

[0025] The processing parameters of the middle part are: using a φ40R5L210 square shoulder milling cutter, adopting a radial priority cutting strategy, a cutting depth of 8mm, a cutting width of 1mm, a rotation speed of S=400r / min, and F=250mm / min.

[0026] The processing parameters at the opening are: using a φ40R5L150 square shoulder milling cutter, adopting a radial priority cutting strategy, cutting depth 10mm, cutting width 1mm, speed S = 400r / min, F = 300mm / min. The beneficial effects of this application are:

[0027] The above processing method solves the deformation and vibration problems in the processing of large titanium alloy ultra-deep cavity thin-walled weak rigidity parts through the inventor's exploration and improvement in actual production. The cutting process is stable, the surface quality after cutting is good, the web thickness and the outer groove width of the side groove meet various engineering requirements, and effectively avoids the problem of the structural size and surface quality of parts that cannot be guaranteed due to the processing deformation and processing vibration of large titanium alloy ultra-deep cavity thin-walled weak rigidity parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of a large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural part.

[0029] Figure 2 Schematic diagram of the rough material of large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural parts.

[0030] Figure 3 Schematic diagram of horizontal axis clamping station for large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural parts.

[0031] Figure 4 Schematic diagram of stepped allowance distribution in rough machining of deep groove cavities of large titanium alloy ultra-deep cavity, thin-walled, weakly rigid, complex structural parts.

[0032] Figure 5 Schematic diagram of the structure of the conformal array auxiliary support device for large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural parts.

[0033] Explanation of the numbers in the figure:

[0034] 1: Large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural parts; 2: side grooves; 3: upper belly plate; 4: lower belly plate; 5: vertical ribs; 6: corners; 7: die forging rough material; 8: process table; 9: reference hole; 10: reference hole; 11: tooling; 12: pressing plate; 13: the upper part of the inner wall of the groove cavity; 14: the middle part of the inner wall of the groove cavity; 15: the lower part of the inner wall of the groove cavity; 16: conformal array type auxiliary support device; 17: support module; 18: groove structure. DETAILED DESCRIPTION

[0035] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0036] The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0037] A processing method for a large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural part, the part has structural features such as groove cavity, ribs, web, corner, and has process characteristics such as deep groove cavity, complex structure, thin wall, weak rigidity. The part processing process includes process planning stage, rough processing stage, heat treatment stage, semi-finishing stage, and finishing stage. It includes the following contents:

[0038] 1) Process planning stage: The part is processed by die forging blank, and there are process tables around the blank for processing, clamping and positioning. The process flow of the part is divided into rough machining - heat treatment - semi-finishing - finishing.

[0039] 2) Rough machining stage: Rough machining is carried out in three stations, and the rough machining adopts the machining method of different features with different allowances. The first and second stations of rough machining are carried out in a three-coordinate vertical machining center. The purpose is to remove the machining allowance of each part of the part, so that the other features of the part except the side groove and the upper and lower webs have uniform allowances, and at the same time, the reference holes for alignment in the subsequent stations of the part are machined. The third station is carried out in a five-axis vertical-horizontal conversion machining center, which adopts horizontal machining and raises the part to avoid interference between the spindle and the machine tool worktable during horizontal axis machining. The allowance in the side groove is distributed in a stepped manner, and the allowance decreases from the bottom of the side groove to the opening.

[0040] 3) In the heat treatment stage, the part together with its machining allowance after rough machining is taken to the process table for stress relief annealing.

[0041] 4) Semi-finishing stage: Before semi-finishing, the position of the reference hole on the process table is first detected by the probe on the machine tool, and compared with the theoretical position of the hole at that location, and the bending deformation and deformation direction of the raw material are analyzed. When the deformation is less than the machining allowance, normal processing can be carried out; when the deformation is greater than the machining allowance, heat treatment is required again to obtain a smaller deformation. The deformation direction data is used as a reference when establishing the machining datum and machining coordinate system for semi-finishing. Semi-finishing is mainly divided into two stations and is carried out on a three-coordinate vertical machining center.

[0042] Semi-finishing adopts the strategy of unequal allowance machining, with smaller first finishing allowances for the inner and outer shapes and larger second finishing allowances for the web surface. The first finishing allowance is 0.5-1mm; the second finishing allowance is 2-3mm.

[0043] 5) The finishing stage is divided into three stations. The first station processes the middle side groove first. This station is carried out on the tooling. The part is raised to avoid interference between the spindle and the machine table during horizontal axis processing. According to the increase in processing depth from shallow to deep, the tool overhang used for processing the side groove also increases in sequence according to the processing depth. Short overhang milling cutter, long overhang milling cutter and super long overhang tool are used for processing. After the side groove size is processed in place, the conformal array auxiliary support device is filled into the side groove and fixed to prevent vibration during subsequent processing of the front and back webs. Since the tolerance band of the side groove width is (-0.2~0), the thickness of the conformal array auxiliary support device adopts a tolerance band of (-0.3~0.25), which ensures that it can be easily placed in the side groove of the part and effectively suppresses the deformation of the part; the outer contour of the conformal array auxiliary support device should meet the requirements of not interfering with the characteristics of the part itself when placed in the side groove and not interfering with the props during processing.

[0044] The second finishing station processes the upper surface web, rib height, vertical rib side walls, etc.; the third finishing station processes the lower surface web, rib height, vertical rib side walls, etc., and finally the process connection ribs around the parts are milled in sections to make the connection between the process table and the parts easy for the fitter to cut off.

[0045] The processing method of large-scale titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural parts is characterized by setting different depth gradients and separating tools with different overhangs during processing to ensure maximization of the cutting efficiency of the ultra-deep cavity structure.

[0046] The processing method of the large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural parts is characterized by adopting a margin allocation strategy based on gradually increasing rigidity to increase the rigidity of the weak rigidity thin-walled structure processing process, selecting appropriate axial and radial layered milling strategies, and suppressing processing chatter;

[0047] The processing method of large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural parts is characterized by designing a suitable conformal array type auxiliary support device to increase the rigidity of the weak rigidity thin-walled structure to ensure the stability of the cutting process.

[0048] The processing method of the large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural part is characterized by

[0049] When machining the side groove, the horizontal axis posture is adopted. Compared with vertical machining, the cuttings generated during the machining process are easy to be discharged from the groove cavity, which effectively avoids the surface quality problems of the side groove of the part caused by chip accumulation and extrusion and friction between the chips and the machined surface of the part.

[0050] Embodiment 1

[0051] The following is an explanation of the CNC machining process of a large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural part 1 as an example.

[0052] See attached Figure 1 The main structural features of the large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural part 1 involved in this embodiment are: its net size is 1670mm×270mm×130mm, the material is TC4 titanium alloy, the depth of the groove cavity 2 of the part reaches 265mm at most, which is an ultra-deep cavity structure, the depth-to-width ratio of the groove cavity 2 is 5:1, the wall thickness of the upper web 3 and the lower web 4 is 3mm, the width-to-thickness ratio is 88:1, the overall rigidity is poor, and vibration and deformation are very likely to occur during processing, and the difficulty of the processing technology is much higher than that of ordinary precision parts; at the same time, the notch size of the groove cavity 2 is 60(0 / -0.2)mm, which is difficult to guarantee, and there is a phenomenon of "closing" after processing. The existing process technology capabilities cannot meet the processing requirements of this type of large titanium alloy ultra-deep cavity thin-walled structure.

[0053] The present invention discloses a processing method for a large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural part. Figure 1 , a processing method for a large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural part 1, the part has structural features such as a groove cavity 2, vertical ribs 5, webs (upper web 3 and lower web 4), corners 6, etc., and has the process characteristics of deep groove cavity, complex structure, thin wall, and weak rigidity.

[0054] The parts processing process includes process planning stage, rough processing stage, heat treatment stage, semi-finishing stage and finishing stage. It is characterized by the following contents:

[0055] 1) Process planning stage: The part is processed using die forging blank 7, and there are process tables 9 around the blank for processing, clamping and positioning. The process flow of the part is divided into four stages: rough machining - heat treatment - semi-finishing - finishing.

[0056] 2) Rough machining stage: Rough machining uses three stations for machining, and adopts machining methods with different structural features and different allowances. Figure 2 The rough machining of the raw material 7 is shown in the figure. The first and second stations are carried out in a three-coordinate vertical machining center. The process table 8 is pressed by a pressure plate, and the alignment is carried out through the two reference holes 9 at the two ends. During rough machining, a 3mm margin is left on the vertical ribs 5 and corners 6 on both sides, and a 5mm margin is left on the surface of the upper and lower webs 3 and 4. At the same time, the reference holes 9 and 10 used for alignment are expanded to φ18. The third rough machining station is carried out in a five-coordinate vertical and horizontal conversion machining center. The parts clamping method is shown in the attached figure. Figure 3 , using horizontal machining to remove the material in the deep groove cavity of the middle side groove 2. This station is carried out on the tooling 11, using the part reference hole 9 and reference hole 10, using the positioning pin to position the part, using the pressing plate 12 to press the part, and using the part to raise the part to avoid interference between the spindle and the machine tool worktable during horizontal axis machining. Refer to the attached Figure 4 At the same time, the inner margin of the side groove 2 is distributed in a stepped manner, the margin 13 of the upper part of the inner wall of the groove cavity is 2 mm, the margin 14 of the middle part of the inner wall of the groove cavity is 4 mm, and the margin 15 of the lower part of the inner wall of the groove cavity is 6 mm.

[0057] 3) In the heat treatment stage, the part together with its machining allowance after rough machining is subjected to stress relief annealing treatment on the process table 8.

[0058] 4) Semi-finishing stage: Before semi-finishing, first use the probe on the machine tool to detect the hole positions of the reference holes 9 and 10 on the process table 8, and compare and analyze them with the theoretical hole positions of the holes at that location to analyze the deformation amount and deformation direction of the rough material. At the same time, detect the deformation amount of the upper web 3 and the lower web 4. When the deformation amount is less than 2mm, normal processing can be carried out. Semi-finishing is mainly divided into two stations, which process the front and back sides respectively. This station is carried out on a three-coordinate vertical machining center. Semi-finishing also adopts the strategy of unequal allowance processing, leaving a 0.5mm allowance on the side of the vertical rib; a 3mm allowance is left on the outer web surface of the upper web 3 and the lower web 4.

[0059] 5) The finishing stage is divided into three stations. The first station processes all dimensions in the middle side groove. The parts clamping method refers to the attached Figure 3 , horizontal machining is used to remove the rough machining allowance in the deep groove cavity of the middle side groove 2. This station is carried out on the tooling 11, using the part reference hole 9 and the reference hole 10, using the positioning pin to position the part, using the pressure plate 12 to press the part, and using the part to raise it to avoid interference between the spindle and the machine tool worktable during horizontal axis machining. When machining the inner allowance of the middle side groove 2, when removing the rough machining allowance 13, a φ40R5L150 square shoulder milling cutter is used, and a radial priority cutting strategy is adopted, with a cutting depth of 10mm, a cutting width of 1mm, a rotation speed of S=400, and F=300. When removing the rough machining allowance 14, a φ40R5L210 square shoulder milling cutter is used, and a radial priority cutting strategy is adopted, with a cutting depth of 8mm, a cutting width of 1mm, and a rotation speed of S=400, and F=250. When removing the rough machining allowance 15, a φ40R5L265 square shoulder milling cutter is used, and a radial priority cutting strategy is adopted, with a cutting depth of 5mm, a cutting width of 1mm, a speed of S=400, and a speed of F=210. The details of other feature machining in the side groove 2 are not described in detail here. Figure 5 After the side groove 2 is processed in place, a conformable array-type auxiliary support device 16 is used to support the inside. The conformable array-type auxiliary support device 16 has an array-type support module 17, and a groove structure 18 is provided between each module. When in use, first place the conformable array-type auxiliary support device 16 into the side groove 2, and the array-type support module 17 contacts and supports the upper and lower web surfaces of the part side groove 2, and then pour the melted paraffin from the groove structure 18, so that it flows and fills the groove structure 18, and finally cools and solidifies, and is used to fix the large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural part 1 and the conformable array-type auxiliary support device 16, so that they form a unified whole, which can effectively avoid vibration when the subsequent workstations process the front and back webs. The thickness of the conformable array-type auxiliary support device adopts a tolerance band of 60 (-0.3 to -0.25), which ensures that it can be easily placed in the side groove of the part and effectively suppresses the deformation of the part;

[0060] The second finishing station processes the upper surface web 3, vertical ribs 5 and corner 6 and other structural dimensions. The third finishing station processes the lower surface web 4, rib height 5, vertical ribs 6, etc. Finally, the process table 8 around the part is milled in sections to make the connection between the part and the process table easy to cut off by the fitter.

[0061] Finally, the process table 8 is removed by the fitter, and the connection between the process table and the part body 1 is trimmed to make it smooth.

[0062] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the method and device in the embodiment of the present invention is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0063] Through the description of the above implementation modes, those skilled in the art can clearly understand that the above implementation modes can be implemented by means of software plus a necessary general hardware platform, and of course by means of hardware, but in many cases the former is a better implementation mode. The above describes the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the above specific implementation modes, which are merely illustrative and not restrictive. Under the enlightenment of the present invention, those skilled in the art can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for processing large titanium alloy ultra-deep cavity thin-wall weak rigidity complex structural parts, characterized by: Here are the steps: Step 1: Fix the die forging raw material on the fixture using the process table around the die forging raw material; Step 2: Rough machining is performed on the die forging blank, and reference holes are machined on two of the process tables. After rough machining, the side wall margins of the side grooves are distributed in a stepped manner; Step 3: heat treat the rough machined parts; Step 4: Check the hole position of the reference hole, compare and analyze the deformation amount and deformation direction of the rough material with the theoretical hole position, and perform semi-finishing when the deformation amount is less than the machining allowance; Step 5: Finish the semi-finished parts and finally mill the connecting ribs between the process table and the parts.

2. The method according to claim 1, characterized in that: In step 1, no less than five process tables are arranged on one side of the straight side or arc side of the die forging blank, no process table is arranged on the side where the side groove is located, and at least two process tables are arranged on the short side adjacent to the side groove.

3. The method according to claim 2, characterized in that: In step 2, rough machining is performed in three stations; The first and second stations are carried out on a three-coordinate vertical machining center, and the upper and lower surfaces of the die forging blank except the side grooves are rough-machined, with an allowance range of 3-5mm; The third workstation is carried out on a five-axis vertical-horizontal conversion machining center, using horizontal machining, and the side groove side wall allowance decreases in steps from the bottom to the opening.

4. The method according to claim 3, characterized in that: The margin bottom of the side groove side wall is 6-8mm; The margin in the middle part is 4-5mm, and the margin at the opening is 2-3mm; when the margin is distributed in steps, it is divided into at least three steps, and the depth of each step is equal.

5. The method according to claim 4, characterized in that: In step 4, during semi-finishing, when the deformation is greater than the machining allowance, heat treatment is required again to obtain a smaller deformation.

6. The method according to claim 5, characterized in that: In step four, semi-finishing is divided into two stations and carried out on a three-coordinate vertical machining center, where the upper and lower surfaces of the part except the side grooves are processed respectively; the first finishing allowance is left on the inner and outer surfaces of the side panels around the part; the second finishing allowance is left on the upper and lower belly plate surfaces; the second finishing allowance is greater than the first finishing allowance.

7. The method according to claim 6, characterized in that: The first finishing allowance is 0.5-1mm; the second finishing allowance is 2-3mm.

8. The method according to claim 7, characterized in that: In step five, finishing is carried out in three stations. The first station processes the side groove, and the processing depth increases from shallow to deep. The tool overhang used also increases in sequence according to the processing depth. Short overhang milling cutter, long overhang milling cutter and extra-long overhang tool are used successively for processing; after the side groove processing is completed, the side groove is fixed with a conformal array auxiliary support device; the second station processes the upper surface web, rib height, and vertical rib side wall; the third station processes the lower surface web, rib height, and vertical rib side wall.

9. The method according to claim 7, characterized in that: The parameters for machining the side groove are as follows: The machining parameters for the bottom of the side groove side wall are: using a φ40R5L265 square shoulder milling cutter, adopting a radial priority cutting strategy, a cutting depth of 5 mm, a cutting width of 1 mm, a speed of S = 400 r / min, and F = 210 mm / min; The machining parameters of the middle part are: using a φ40R5L210 square shoulder milling cutter, adopting a radial priority cutting strategy, cutting depth 8mm, cutting width 1mm, speed S = 400r / min, F = 250mm / min; The processing parameters at the opening are: using a φ40R5L150 square shoulder milling cutter, adopting a radial priority cutting strategy, a cutting depth of 10mm, a cutting width of 1mm, a speed of S=400r / min, and F=300mm / min.

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