A method for fabricating large, complex titanium alloy ultra-deep cavity, thin-walled, weakly rigid structural components.

Abstract

This invention belongs to the field of CNC machining technology and discloses a machining method for a large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural part. The steps are as follows: Step 1: Fix the forged blank on a fixture using the process tables around the forged blank; Step 2: Roughly machine the forged blank and machine reference holes on two of the process tables. After rough machining, the side wall allowance of the side groove is distributed in a stepped manner; Step 3: Heat treat the part after rough machining; Step 4: Detect the position of the reference holes and compare it with the theoretical hole position to analyze the deformation amount and direction of the blank. When the deformation amount is less than the machining allowance, perform semi-finishing; Step 5: Finish machine the part after semi-finishing, and finally mill the connecting rib between the process table and the part.

Description

Technical Field

[0001] This invention belongs to the field of CNC machining technology, and in particular, it is a machining method for large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural parts. Background Technology

[0002] Titanium alloys are widely used in the aerospace field due to their superior physicochemical properties. However, thin-walled titanium alloy parts, due to their low stiffness, are prone to chatter and deformation under cutting forces, resulting in poor surface quality and difficulty in ensuring dimensional accuracy. With the increasing demands for long lifespan, lightweight design, and high reliability in modern aircraft, some critical load-bearing components are being integrated with titanium alloys. The increased structural performance requirements have made the manufacturing technology of large titanium alloy structural components a key technology in aircraft development. However, under the trend of increasingly integrated, complex, and precise titanium alloy structural components, large-scale aerospace titanium alloy ultra-deep cavity thin-walled structures remain a major challenge in the field of CNC machining both domestically and internationally. Key technologies still have shortcomings, and products are prone to machining chatter and deformation, seriously affecting product quality. The efficient and precise machining and manufacturing technology of ultra-deep cavity thin-walled complex structural components still faces severe challenges. Summary of the Invention

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

[0005] A method for machining large, ultra-deep cavity, thin-walled, weakly rigid complex titanium alloy structural components, comprising the following steps:

[0006] Step 1: Use the process table around the forging blank to fix the forging blank on the fixture;

[0007] Step 2: Roughly machine the forging blank, and machine datum holes on two of the process tables. After rough machining, the sidewall allowance of the side groove is distributed in a stepped manner. The two process holes are selected on the two furthest process tables as much as possible to reduce the impact of deformation on the datum hole movement on subsequent machining. The stepped distribution of the sidewall allowance of the side groove after rough machining ensures that there is a sufficiently large machining allowance to guarantee rigidity during the finishing process at the depth of the side groove.

[0008] Step 3: Heat treatment is performed on the rough-machined parts. The heat treatment is a stress relief treatment. The main purpose of stress relief for titanium alloys is to eliminate the residual stress in the parts after rough machining as much as possible, so that the parts can obtain better finishing conditions, and at the same time reduce the deformation of the parts after finishing.

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

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

[0011] Furthermore, in step one, no fewer than five process stations are set on one side of the straight or curved edge of the die forging blank, no process station is set on the side where the side groove is located, and at least two process stations are set on the short side adjacent to the side groove.

[0012] Furthermore, in step two, the rough machining is performed at three stations:

[0013] The first and second stations are carried out in a three-axis vertical machining center. The upper and lower surfaces of the die forging blank, except for the side groove, are rough machined respectively. The second rough machining allowance at the upper and lower web plates is generally 3-5mm, and the first rough machining allowance for the remaining parts is generally 2-3mm.

[0014] The third station is operated in a five-axis vertical-horizontal conversion machining center, using horizontal machining. The allowance of the side groove sidewall decreases in a step-like manner from the bottom to the opening.

[0015] Furthermore, the allowance on the sidewall of the side channel is 6-8mm at the bottom; 4-5mm in the middle section; and 2-3mm at the opening. When the allowance is distributed in steps, there should be at least three steps, with each step having the same depth.

[0016] Furthermore, in step four, during semi-finishing, if the deformation exceeds the machining allowance, it is necessary to consider re-heat treatment to obtain a smaller deformation.

[0017] Furthermore, in step four, the semi-finishing is divided into two stations, which are carried out on a three-axis vertical machining center. The upper and lower surfaces of the part, excluding the side grooves, are machined respectively. A first finishing allowance is left on the inner and outer surfaces of the four side plates; a second finishing allowance is left on the upper and lower web surfaces; the second finishing allowance is greater than the first finishing allowance.

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

[0019] Furthermore, in step five, the finishing process is carried out in three stations. The first station processes the side groove, with the processing depth increasing from shallow to deep. The tool overhang also increases sequentially according to the processing depth, using short overhang milling cutters, long overhang milling cutters, and extra-long overhang tools in sequence.

[0020] After the side groove is machined, a conformal array-type auxiliary support device is used to fix the side groove.

[0021] The second workstation processes the upper surface web, rib height, and vertical rib sidewalls.

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

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

[0024] The machining parameters for the bottom of the side groove sidewall are as follows: use a φ40R5L265 square shoulder end mill, adopt a radial priority cutting strategy, cut depth 5mm, cut width 1mm, spindle speed S=400r / min, F=210mm / min.

[0025] The machining parameters for the middle section are as follows: using a φ40R5L210 square shoulder end mill, adopting a radial priority cutting strategy, a cutting depth of 8mm, a cutting width of 1mm, a spindle speed of S = 400r / min, and F = 250mm / min.

[0026] The machining parameters for the opening are as follows: using a φ40R5L150 square shoulder end mill, employing a radial priority cutting strategy, a depth of cut of 10mm, a width of cut of 1mm, a spindle speed of S = 400r / min, and F = 300mm / min. The beneficial effects of this application are:

[0027] Through the inventors' exploration and improvement in actual production, the above-mentioned processing method has solved the problems of deformation and vibration in the processing of large titanium alloy ultra-deep cavity thin-walled weak rigid parts. The cutting process is stable, the surface quality after cutting is good, and the web thickness and the outer groove width of the side groove meet the various engineering requirements. It effectively avoids the problem of part structure dimensions and surface quality that cannot be guaranteed due to deformation and vibration during the processing of large titanium alloy ultra-deep cavity thin-walled weak rigid parts. Attached Figure Description

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

[0029] Figure 2 Schematic diagram of raw material for a large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural component.

[0030] Figure 3 Schematic diagram of horizontal shaft clamping for large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural components.

[0031] Figure 4 A schematic diagram of the stepped allowance distribution in the rough machining of deep grooves in large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural parts.

[0032] Figure 5 A schematic diagram of a conformal array auxiliary support device for a large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structure.

[0033] Explanation of the numbering in the diagram:

[0034] 1: Large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural component; 2: Side groove; 3: Upper web plate; 4: Lower web plate; 5: Vertical rib; 6: Corner; 7: Forged blank; 8: Process table; 9: Reference hole; 10: Reference hole; 11: Tooling; 12: Pressure plate; 13: Upper part of the inner wall of the groove cavity; 14: Middle part of the inner wall of the groove cavity; 15: Lower part of the inner wall of the groove cavity; 16: Conformal array type auxiliary support device; 17: Support module; 18: Groove structure. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0036] The terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0037] A method for machining a large, ultra-deep cavity, thin-walled, weakly rigid complex structure made of titanium alloy is disclosed. This part features structural characteristics such as grooves, vertical ribs, webs, and corners, and exhibits manufacturability characteristics including deep cavities, complex structure, thin walls, and weak rigidity. The machining process includes a process planning stage, a rough machining stage, a heat treatment stage, a semi-finishing stage, and a finish machining stage. It includes the following:

[0038] 1) Process planning stage: This part is machined from forged blank. The blank has process tables around its perimeter for clamping and positioning. The process flow for this part is divided into rough machining, heat treatment, semi-finishing, and finishing.

[0039] 2) Rough Machining Stage: Rough machining employs a three-station process with varying allowances for different features. The first and second stations are located on a three-axis vertical machining center. Their purpose is to remove machining allowances from all parts of the part, ensuring uniform allowances for all features except the side grooves and upper and lower webs. Simultaneously, they machine the reference holes for alignment in subsequent stations. The third station is located on a five-axis vertical-to-horizontal conversion machining center, using horizontal machining to elevate the part and avoid interference between the spindle and the machine table during horizontal spindle machining. The allowance within the side grooves is distributed in a stepped manner, decreasing from the bottom of the groove towards the opening.

[0040] 3) During the heat treatment stage, the part, along with its machining allowance after rough machining, is subjected to stress-relieving annealing on a process table.

[0041] 4) Semi-finishing stage: Before semi-finishing, the position of the reference hole on the process table is first detected by a probe on the machine tool. This position is then compared with the theoretical hole position to analyze the bending deformation and direction of the raw material. If the deformation is less than the machining allowance, normal machining can proceed. If the deformation is greater than the machining allowance, heat treatment is required to achieve a smaller deformation. The deformation direction data is used as a reference when establishing the machining datum and coordinate system for semi-finishing. Semi-finishing mainly consists of two stations, performed on a three-axis vertical machining center.

[0042] The semi-finishing process employs a unequal allowance machining strategy, with a smaller first finishing allowance for the inner and outer surfaces, and a larger second finishing allowance 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 carried out in three stations. The first station processes the middle side groove first. This station is performed on a fixture, raising the part to avoid interference between the spindle and the machine tool table during horizontal spindle machining. As the machining depth increases from shallow to deep, the tool overhang used for machining the side groove also increases sequentially, using short overhang milling cutters, long overhang milling cutters, and then extra-long overhang tools. After the side groove dimensions are achieved, a conformal array auxiliary support device is filled into the side groove and fixed to prevent vibration during subsequent machining of the front and back webs. Since the side groove width tolerance is (-0.2~0), the thickness of the conformal array auxiliary support device uses a tolerance of (-0.3~0.25), ensuring easy placement within the part's side groove and effectively suppressing part deformation. The outline of the conformal array auxiliary support device should ensure that it does not interfere with the part's characteristics when placed in the side groove and does not interfere with the fixture during machining.

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

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

[0046] The method for machining 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 during machining, and selecting appropriate axial and radial layer milling strategies to suppress machining chatter.

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

[0048] The method for processing large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural parts is characterized by:

[0049] When machining the side groove, a horizontal spindle posture is adopted. Compared with vertical machining, the cuttings generated during the machining process are more easily discharged from the groove cavity, effectively avoiding surface quality problems of the side groove caused by chip accumulation and the squeezing and friction between the chips and the machined surface of the part.

[0050] Example 1

[0051] The following example illustrates the CNC machining process of a large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural component 1.

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

[0053] This invention discloses a method for machining large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural components, as shown in the attached figure. Figure 1 A machining method for a large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural component 1. The component has structural features such as a groove cavity 2, vertical ribs 5, webs (upper web 3 and lower web 4), and corners 6, and has the processability characteristics of deep groove cavity, complex structure, thin wall and weak rigidity.

[0054] The machining process for this part includes a process planning stage, a rough machining stage, a heat treatment stage, a semi-finishing stage, and a finishing stage. Its key features include the following:

[0055] 1) Process planning stage: This part is machined using die-forged blank 7. The blank has process tables 9 around it for machining, clamping, and positioning. The process flow of this part is divided into four stages: rough machining, heat treatment, semi-finishing, and finishing.

[0056] 2) Rough Machining Stage: Rough machining employs a three-station machining process, using machining methods with varying allowances for different structural features. Rough machining utilizes... Figure 2 The rough workpiece 7 shown is processed in two stations on a three-axis vertical machining center. The process table 8 is clamped by a pressure plate, and alignment is achieved through two reference holes 9 at both ends. During rough machining, a 3mm allowance is left for the vertical ribs 5 and corners 6 on both sides, and a 5mm allowance is left for the surfaces of the upper web 3 and lower web 4. Simultaneously, the reference holes 9 and 10 used for alignment are enlarged to φ18. The third rough machining station is performed on a five-axis vertical-horizontal conversion machining center. The part clamping method is shown in the attached diagram. Figure 3 The material in the deep cavity of the middle side groove 2 is removed using a horizontal machining method. This station is performed on fixture 11, using the part's reference holes 9 and 10, locating pins to position the part, pressure plate 12 to clamp the part, and shims to elevate the part to avoid interference between the spindle and the machine tool table during horizontal spindle machining. (See attached...) Figure 4 Meanwhile, the inner margin of the side groove 2 is distributed in a stepped manner, with the upper margin 13 of the inner wall of the groove cavity being 2mm, the middle margin 14 of the inner wall of the groove cavity being 4mm, and the lower margin 15 of the inner wall of the groove cavity being 6mm.

[0057] 3) During the heat treatment stage, the part, along with its machining allowance after rough machining, is subjected to stress-relieving annealing on process table 8.

[0058] 4) Semi-finishing stage: Before semi-finishing, the positions of reference holes 9 and 10 on the process table 8 are first detected using a probe on the machine tool. These positions are then compared with the theoretical positions of the holes to analyze the deformation amount and direction of the raw material. Simultaneously, the deformation of the upper web 3 and lower web 4 is detected. If the deformation is less than 2mm, normal machining can proceed. Semi-finishing is mainly divided into two stations, machining the front and back sides respectively. This station is performed on a three-axis vertical machining center. The semi-finishing also adopts an unequal allowance machining strategy: a 0.5mm allowance is left on the sides of the vertical ribs; a 3mm allowance is left on the outer web surfaces of the upper web 3 and lower web 4.

[0059] 5) The finishing stage is carried out in three stations. The first station processes all dimensions within the central side groove; the part clamping method is shown in the appendix. Figure 3 The roughing allowance in the deep cavity of the intermediate side groove 2 is removed using a horizontal machining method. This station is performed on fixture 11, using the part's reference holes 9 and 10, positioning pins to locate the part, clamping plate 12 to hold the part in place, and raising the part to avoid interference between the spindle and the machine tool table during horizontal spindle machining. When machining the inner allowance of the intermediate side groove 2, when removing the roughing allowance 13, a φ40R5L150 square shoulder end mill is used, employing a radial priority cutting strategy, with a depth of cut of 10mm, a cut width of 1mm, and a spindle speed S=400, F=300. When removing the roughing allowance 14, a φ40R5L210 square shoulder end mill is used, employing a radial priority cutting strategy, with a depth of cut of 8mm, a cut width of 1mm, and a spindle speed S=400, F=250. When removing the roughing allowance of 15mm, a φ40R5L265 square shoulder end mill was used, employing a radial priority cutting strategy, with a depth of cut of 5mm, a cut width of 1mm, and a spindle speed of S=400 and F=210. Machining details for other features within side groove 2 are not described in detail here. See attached... Figure 5 After the side groove 2 is machined, a conformal array-type auxiliary support device 16 is used to support the interior. The conformal array-type auxiliary support device 16 has an array-type support module 17, and each module has a groove structure 18 between them. In use, the conformal array-type auxiliary support device 16 is first placed into the side groove 2. The array support module 17 contacts and supports the upper and lower web surfaces of the side groove 2. Then, molten paraffin is poured into the groove structure 18, allowing it to flow and fill the groove structure 18. Finally, it cools and solidifies. This is used to fix the large titanium alloy ultra-deep cavity thin-walled weak rigidity complex structural part 1 and the conformal array-type auxiliary support device 16, making them a unified whole. This can effectively prevent vibration during subsequent machining of the front and back web surfaces. The thickness of the conformal array-type auxiliary support device adopts a tolerance zone of 60 (-0.3 to -0.25) to ensure that it can be easily placed into the side groove of the part and effectively suppress the deformation of the part.

[0060] The second finishing station processes the upper surface web plate 3, vertical rib 5, and corner 6, etc. The third finishing station processes the lower surface web plate 4, rib height 5, vertical rib 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 for the fitter to cut.

[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 the transition smooth.

[0062] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0063] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art, under the guidance of the present invention, can make many other forms without departing from the spirit and scope of protection of the claims, and all such forms are within the protection scope of the present invention.

Claims

1. A method for machining large titanium alloy ultra-deep cavity thin-walled weakly rigid complex structural components, characterized in that: The steps are as follows: Step 1: Use the process table around the forging blank to fix the forging blank on the fixture; Step 2: Roughly machine the blank forging part and machine the reference holes on two of the process tables. After rough machining, the side wall allowance of the side groove is distributed in a stepped manner; the side wall allowance at the bottom of the side groove is 6-8mm; the allowance in the middle part is 4-5mm; and the allowance at the opening is 2-3mm. Step 3: Perform heat treatment on the rough-machined parts; Step 4: Detect the position of the reference hole and compare it with the theoretical hole position to analyze the deformation amount and direction of the raw material. When the deformation amount is less than the machining allowance, perform semi-finishing. Step 5: Perform finishing on the semi-finished parts, including the final milling of the connecting rib between the milling table and the part. Finishing is done in three stations. The first station processes the side grooves, with the machining depth increasing from shallow to deep. The tool overhang also increases sequentially with the machining depth, using short overhang milling cutters, long overhang milling cutters, and extra-long overhang tools in that order. After the side grooves are machined, a conformal array auxiliary support device is used to fix them. The side groove width tolerance is (-0.2~0), and the thickness of the conformal array auxiliary support device is (…). The tolerance zone is -0.3 to 0.

25. The conformal array auxiliary support device has an array support module with a groove structure between each module. When in use, the conformal array auxiliary support device is first placed in the side groove. The array support module contacts and supports the upper and lower web surfaces of the part's side groove. Then, the molten paraffin is poured into the groove structure, allowing it to flow and fill the groove structure, and finally cool and solidify. The second station processes the upper surface web, rib height, and vertical rib sidewalls. The third station processes the lower surface web, rib height, and vertical rib sidewalls.

2. The method according to claim 1, characterized in that: In step one, no fewer than five process stations are set on one side of the straight or curved edge of the die forging blank, no process station is set on the side where the side groove is located, and at least two process stations are set on the short side adjacent to the side groove.

3. The method according to claim 2, characterized in that: In step two, the rough machining is performed at three stations; The first and second stations are carried out in a three-axis vertical machining center, where the upper and lower surfaces of the forging blank, except for the side groove, are rough machined, with a allowance range of 3-5mm. The third station is operated in a five-axis vertical-horizontal conversion machining center, using horizontal machining. The allowance of the side groove sidewall decreases in a step-like manner from the bottom to the opening.

4. The method according to claim 3, characterized in that: When the margin is distributed in a stepped manner, it should be divided into at least three steps, with each step having the same depth.

5. The method according to claim 4, characterized in that: In step four, during semi-finishing, if the deformation exceeds the machining allowance, heat treatment must be performed again to obtain a smaller deformation.

6. The method according to claim 5, characterized in that: In step four, the semi-finishing is divided into two stations, which are carried out on a three-axis vertical machining center. The upper and lower surfaces of the part, excluding the side grooves, are machined respectively. The inner and outer surfaces of the side plates around the part are left with a first finishing allowance. The upper and lower webs are left with a second finishing allowance. 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: The parameters for machining the side groove are as follows: The machining parameters for the bottom of the side groove sidewall are as follows: use a φ40R5L265 square shoulder end mill, adopt a radial priority cutting strategy, cut depth 5mm, cut width 1mm, spindle speed S=400r / min, F=210 mm / min; The machining parameters for the middle section are as follows: using a φ40R5L210 square shoulder end mill, adopting a radial priority cutting strategy, a depth of cut of 8mm, a width of cut of 1mm, a spindle speed of S=400 r / min, and a spindle speed of F=250 mm / min; The machining parameters for the opening are as follows: use a φ40R5L150 square shoulder end mill, adopt a radial priority cutting strategy, cut depth 10mm, cut width 1mm, spindle speed S=400 r / min, F=300 mm / min.

Images