A method for processing an integral blade disk

Abstract

The present invention provides a method for processing an integral blade disk, and relates to the technical field of metal processing. The process route of the integral blade disk processing of the present invention sequentially includes: blank, CNC rough turning, two-step CNC rough milling, vacuum heat treatment, benchmark repair, semi-finishing blade milling, semi-finishing turning, secondary vacuum heat treatment, secondary benchmark repair, fine milling blade profile, fine turning, polishing, clamp repair, appearance inspection, fluorescent inspection, shot peening, vibration finishing, spraying, static balancing, final inspection, and storage. The present invention controls the deformation of the integral blade disk during the processing process.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, and in particular to a method for processing an integral blade disk. Background Art

[0002] The integral blisk is a new type of structural component designed to meet the needs of high-performance aircraft engines. It integrates the engine rotor blades and the wheel disc, eliminating the tenons, mortise and tenon grooves and locking devices in traditional connections, reducing the structural weight and the number of parts, avoiding tenon airflow losses, improving aerodynamic efficiency, and greatly simplifying the engine structure. It has now been widely used in military and civil aircraft engines in various countries.

[0003] As a major improved component of the new aircraft engine, compared with the original large blade disk, the integral blade disk is thinner, has a larger torsion angle, and a longer chord length. The integral blade disk is processed by overall milling, and the processing removal volume is as high as more than 70%.

[0004] Titanium alloy is a difficult-to-cut material, prone to cutting heat accumulation, tool sticking, and more difficult to control deformation. Therefore, the main technical bottleneck in the cutting process of TC17 titanium alloy super-large integral blades is deformation control. Summary of the invention

[0005] The object of the present invention is to develop a method for machining an integral blade disk, which can control the deformation of the integral blade disk during the machining process.

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

[0007] A method for processing an integral blade disk, wherein the processing route of the integral blade disk sequentially includes: blank, CNC rough turning, two-step CNC rough milling, vacuum heat treatment, benchmark repair, semi-finishing blade milling, semi-finishing turning, secondary vacuum heat treatment, secondary benchmark repair, fine milling blade profile, fine turning, polishing, clamp repair, appearance inspection, fluorescent inspection, shot peening, vibration finishing, spraying, static balancing, final inspection, and warehousing;

[0008] In the CNC rough turning process, the blank blade tip allowance is used for layered processing, and the parameters are adjusted up and down based on the on-site processing experience. Different cutting speeds, feed rates and cutting depths are used under the premise of fixing two parameters and changing one parameter. The processing is divided into 9 times, and the processing parameter database is collected and established;

[0009] According to the calculation formulas of cutting speed, feed rate and cutting depth, calculation and analysis are performed respectively, and a curve statistical graph is established based on the calculation and analysis data, and the optimal processing parameters are selected based on the curve graph. The extreme value of the curve in the curve graph corresponds to the optimal processing parameter;

[0010] During the rough milling process, the parts are fixed on the five-axis boring and milling table in a flat manner. Combined with the comprehensive and effective use of machine tools, ordinary large-face milling cutters and corn cob milling cutters are used to remove the machining allowance by turning over and evenly distributing the machining. By effectively using the simulation function of the simulation software, program path interference and tool overcutting phenomena are predicted in advance, and the machining program is planned well. Ordinary machine tools and ordinary tools are used to remove the machining allowance to the maximum extent.

[0011] After removing the machining allowance from the parts, remove the remaining rough machining allowance;

[0012] When the rough machining allowance is 2mm, vacuum heat treatment is carried out, and when the allowance is 0.6mm, secondary vacuum heat treatment is carried out;

[0013] When fine milling the blade shape, use paraffin to fill the blade. You can also use gypsum, foam glue, and anti-vibration mud to fill the blade.

[0014] During the rough milling process, the rough machining allowance is used to perform test machining on specific parts. The parts after the test machining are used for testing and machining efficiency analysis. One of the following solutions is selected based on the test results:

[0015] The first method is to use a symmetrically distributed processing scheme, that is, when the first blisk margin is processed, the machine tool table rotates 180 degrees to process the second blisk margin, then rotates 90 degrees to process the third blisk margin, and the processing is completed in sequence;

[0016] The second method is to use isolation processing and spacer injection molding, that is, after processing one inter-blade margin clockwise, isolate an integral blade disk and process the third integral blade disk. The processing sequence is similar. After the spacer is processed, the processed cavity is injection molded to increase the rigidity of the adjacent integral blade disk, and then the remaining inter-blade margin is removed.

[0017] The third method: adopting a one-to-two roughing and finishing synchronous processing scheme, that is, the roughing and finishing of two adjacent blisks are processed synchronously;

[0018] The processing method also includes a chatter suppression method based on the non-uniform allowance design of thin-walled parts involved in the semi-finishing milling of blade profiles and semi-finishing turning in the integral blade disk processing route, including:

[0019] According to the machining experience and the CAD model of the blisk, the initial cutting parameters including cutting width, feed speed and spindle speed and the initial distribution state of the semi-finishing allowance of the blisk are determined;

[0020] When machining thin-walled parts, the cutting force model first calculates the nominal cutting force based on the initial cutting parameters at each tool position, and inputs it into the finite element model to simulate the dynamic cutting process. Based on the machining dynamic information obtained by the finite element calculation, the contact conditions between the cutter tooth microelement and the workpiece are updated and fed back to the cutting force model for recalculation. When the difference between the two predicted cutting force magnitudes meets the set tolerance requirements, the iterative process ends.

[0021] According to the calculation results output from the finite element model, the dynamic response characteristics of the thin-walled integral blade disk in the actual machining process are analyzed, and the semi-finishing allowance distribution state of the blade body is adjusted to improve the rigidity distribution of the blade tip and the leading and trailing edge areas during the finishing process. The spiral tool position trajectory is used to preferentially remove the machining allowance in the blade tip area. At the same time, by optimizing and controlling the tool axis vector direction at the tool position point on the tool path, the force state of the tool and the integral blade disk is adjusted so that the cutting force is mainly along the tool axis direction and the blade body tangent plane direction, that is, the direction with the best rigidity. A large iterative cycle process is formed between the cutting force model, the finite element model, the allowance distribution optimization design model and the spiral tool trajectory generation model.

[0022] The final output result is the optimized distribution state of the semi-finishing allowance of the integral blade, the optimized tool trajectory and the optimized cutting parameters. The cutting stability area is determined and optimized. The modal parameters of the machine tool, tool and integral blade system structure are identified by using the experimental modal analysis method. The size of the dynamic component of the instantaneous cutting thickness caused by vibration deformation is determined, and the milling dynamics equation is established. The harmonic function and frequency response function are used in the frequency domain to describe the vibration behavior at the chatter frequency, and then the milling stability limit diagram is drawn to determine the stability and instability areas of the cutting system, thereby suppressing chatter.

[0023] Optionally, in the fine milling of the blade profile, the tool path strategy needs to be selected and matched based on the torsional curvature of the blade profile, the complexity of the surface, and the special requirements of the root transition and the leading and trailing edge transition. The tool path routes include: spiral milling, symmetrical spiral milling, flipping reciprocating milling, leading and trailing edge interpolation milling, and scanning milling with an inclination angle.

[0024] Optionally, the processing method also includes a cutting method for complex thin-walled structural parts involved in fine milling of blade profiles in the integral blade disk processing process route, including:

[0025] In view of the complex channel shape and boundary constraints of the complex thin-walled structure of the integral blade disk, the machinability analysis algorithm of the complex channel is used to determine the reachable area and cutting direction of the tool, and the entire channel is divided into multiple processing areas. The tool axis direction is optimized as a whole in each area, and the five-coordinate branch fixed axis control processing method is used to complete the rough processing of each area;

[0026] For the rough machining of forging blanks made of difficult-to-machine materials, new processes such as drilling instead of milling, plunge milling, and rapid milling are adopted, and tool parameters and cutting parameters are adjusted through process tests;

[0027] In view of the residual stress generated by large forging blanks with large removal amount and the deformation of the integral blade disk structure caused by it, the clamping optimization, rough machining, heat treatment, stabilization treatment, benchmark measurement and benchmark repair methods are adopted to achieve comprehensive control of rough machining deformation compensation and material structure performance, reduce the allowance of the integral blade disk in the later processing, and avoid re-heat treatment during the integral blade disk processing stage;

[0028] Aiming at the problem of machine tool servo delay in five-axis high-speed finishing of complex thin-walled integral blisk, the stability of the thin-walled integral blisk machining process, surface machining accuracy and surface quality are guaranteed through multi-body dynamics optimization and error compensation of the five-axis high-speed machining tool trajectory.

[0029] Optionally, the cutting method for complex thin-walled structural parts includes feature modeling, cutting parameter optimization, deformation control and chatter suppression, and CNC programming. The process solution is obtained through feature modeling, cutting parameter optimization, deformation control and chatter suppression, and then CNC machining program compilation, digital simulation and physical simulation, overall structural parts machining and inspection analysis are carried out. If the digital simulation and physical simulation, overall structural parts machining and inspection analysis meet the design requirements, the data are entered into the cutting parameter library and the tool parameter library. If the digital simulation and physical simulation, overall structural parts machining and inspection analysis do not meet the design requirements, process tests are carried out.

[0030] Optionally, the processing method also includes a method for suppressing chatter during high-speed milling of thin-walled parts involved in fine milling of blade profiles in the integral blade disc processing process route, including:

[0031] Increase the rigidity and damping of the machine tool structure and use vibration absorbers or additional vibration elimination devices;

[0032] Adjust the control method of cutting parameters, online adjust the cutting parameters including spindle speed, feed rate, cutting depth, tool angle, etc., and change the cutting stiffness and cutting damping;

[0033] Adjust or replace cutting tools to eliminate chatter during milling;

[0034] Adjust the clamping method and appropriately increase auxiliary supports to improve the rigidity of the workpiece system and suppress the chatter generated during the milling of thin-walled parts.

[0035] Optionally, the processing method also includes a method for controlling residual stress and deformation of thin-walled parts involved in fine milling of blade profiles in the integral blade processing process route, including:

[0036] By using numerical simulation technology to simulate the machining process before machining, the machining process is analyzed, the influence of various parameters on the residual stress of parts is determined, the deformation and cracking of complex parts during machining are predicted, and the optimization machining plan with the goal of controlling residual stress and deformation is studied. The machining process based on residual stress symmetry is adopted and the clamping positioning is optimized to weaken the deformation caused by residual stress during and after machining, and control the machining accuracy of parts.

[0037] Optionally, the processing method also includes an electromagnetic coupling processing method for equalizing residual stress of the integral blade disk processing involved in the precision milling of the blade profile in the integral blade disk processing process route, including:

[0038] A single TC17 blade specimen in the integral blisk was selected as the research object;

[0039] Computer simulation: Establish a three-dimensional model of the electromagnetic coupling treatment TC17 blade disk test piece. Use COMSOL simulation software to input different electromagnetic coupling treatment process parameters, analyze and study the corresponding relationship between the temperature gradient change, Lorentz force, current density, stress strain and residual stress of the material, and specify the process plan for electromagnetic coupling treatment of the TC17 blade disk test piece based on the simulation results;

[0040] Experimental research: Design and prepare special tooling and fixtures for electromagnetic coupling treatment of blade disk test pieces, use different electromagnetic coupling treatment process parameters to treat the test pieces, select key parts of the blade for multi-point calibration, carry out quasi-in-situ residual stress detection tests, use X-ray diffraction residual stress non-destructive detection method to detect residual stress at the calibrated positions, compare and analyze the absolute value of residual stress and the change law of residual stress direction before and after electromagnetic coupling treatment, measure the resistance value and magnetic saturation intensity of the blank before and after electromagnetic coupling treatment, and study the influence of electromagnetic coupling external field treatment process parameters on the residual stress of TC17 blade disk specimen processing based on the experimental results, and establish the process specifications for equalizing the residual stress of TC17 blade disk specimen processing using electromagnetic coupling treatment technology.

[0041] Optionally, the processing method also includes a method for predicting and compensating elastic deformation of thin-walled parts involved in the precision milling of blade profiles in the integral blade processing process route, including:

[0042] At any tool position, according to the initial processing conditions, after iterative calculation between the cutting force model and the finite element model of the tool and workpiece, the equilibrium state of the flexible cutting force (Fx, Fy, Fz) and the processing deformation (ux, uy, uz) at the tool position is obtained. After the tool trajectory is corrected, the tool is closer to the theoretical cutting position, and the actual cutting width and cutting force are larger than the predicted values ​​of the last iteration. As a result, the tool and the workpiece will be in different equilibrium positions. If the tool trajectory is compensated only once, the cutter teeth still cannot reach the cutting position required by the process. Instead, the contact conditions at the tool position must be updated according to the processing deformation information, and the cutting force and processing deformation must be recalculated to correct and compensate the tool trajectory in a cyclic and progressive manner.

[0043] The beneficial effects of the present invention are:

[0044] The ultra-large fan integral blade disk processed by the present invention uses an ordinary horizontal boring and milling machine to perform rough machining of the blades. The blank is an ultra-large TC17 titanium alloy Class I die forging with a diameter greater than 1300 mm. The blank weight reaches 985 kg, and the material removal rate of the final product reaches 70%. Combined with the characteristics of low equipment value and depreciation cost, high equipment rigidity and simple operation of ordinary horizontal boring and milling machines, the use of ordinary boring and milling machines in the rough machining process can achieve efficient and low-cost machining effects. In the research process, cutting tools (including tool ratios) that are suitable for high hardness and high strength of titanium alloy materials are developed. The design and research of the blade profile (such as the parameters, coating type, and substrate material) are carried out to ensure the life of the tool and the cutting efficiency. The cutting parameters, such as cutting speed, feed speed, cutting depth and other parameter combinations, are optimized by combining experiments and simulation technology to improve the processing efficiency and accuracy. A reasonable processing process is formulated according to the shape and size of the blade disk, including positioning, clamping, rough processing and other links to ensure the processing accuracy and efficiency. The research results will break through the demand restrictions of the five-axis machining center for the rough processing of the blade profile of the integral blade disk, and realize an efficient and low-cost blade profile rough processing process;

[0045] The present invention carries out research on cutting technology of complex thin-walled structural parts, research on chatter suppression technology of high-speed milling of thin-walled parts, control method of residual stress deformation in efficient and precise machining of thin-walled parts, research on electromagnetic coupling processing technology for equalizing residual stress in integral blade disk machining, and research on elastic deformation prediction and compensation method in efficient and precise machining of thin-walled parts. The research results will realize residual stress detection in integral blade disk machining and residual stress regulation in specimen machining, and control deformation in the machining process of large thin-walled parts;

[0046] The main technical bottleneck of the integral blade disk in the cutting process is anti-deformation control. On the basis of existing research, combined with the characteristics of alloy materials and part structures, through theoretical analysis, experimental verification and physical simulation methods, the influence of material removal methods in the cutting process on blade deformation is mastered, and the process route and parameters of efficient and precise machining of integral blade disks are optimized, forming a set of multi-axis efficient and precise machining technology solutions for ultra-large titanium alloy integral blade disks. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0048] Figure 1 This is a schematic diagram of the placement of horizontal five-axis boring and milling parts;

[0049] Figure 2 This is a schematic diagram of the simultaneous roughing and fine processing of "one supporting two";

[0050] Figure 3 Research solutions for cutting process of complex thin-walled structural parts;

[0051] Figure 4 It is the overall scheme of chatter suppression technology for high-speed milling;

[0052] Figure 5 Chatter suppression solution for precision cutting;

[0053] Figure 6 A research program for residual stress and deformation control in efficient and precise machining of thin-walled parts;

[0054] Figure 7 Research scheme for electromagnetic coupling processing technology to equalize residual stress in blisk machining;

[0055] Figure 8 It is a compensation scheme for machining elastic deformation errors. DETAILED DESCRIPTION

[0056] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0057] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0058] The invention discloses a method for processing an integral blade disk, wherein the integral blade disk is an ultra-large fan integral blade disk with a diameter of Φ1114 mm, and the integral blade disk processing process route comprises: blank (die forging) → CNC rough turning → CNC rough milling (two steps) → vacuum heat treatment → datum repair → semi-finishing blade profile milling → semi-finishing turning → vacuum heat treatment (secondary) → secondary datum repair → fine milling blade profile milling → fine turning → polishing → clamp repair → appearance inspection → fluorescent inspection → shot peening → vibration finishing → spraying → static balancing → final inspection → warehousing.

[0059] Compared with the previous process route of the integral blade, this process route adds one more rough milling blade, semi-finishing and heat treatment process in consideration of the machine tool load and the control of deformation after fine milling. Its purpose is to use general machine tools to remove machining allowances and reduce the weight of parts as much as possible. On the other hand, it reduces the stress release during fine milling of blades and reduces part deformation.

[0060] The research contents of the present invention include research on machining technology of super-large integral blisks, processing technology of blades of super-large fan integral blisks, process technology of deep cavity of spoke plates of super-large fan integral blisks, tooling design technology of super-large fan integral blisks, tool design technology of super-large fan integral blisks, research on cutting technology of complex thin-walled structural parts, vibration suppression technology of high-speed milling of thin-walled parts, control method of residual stress deformation of efficient and precise machining of thin-walled parts, electromagnetic coupling processing technology of residual stress equalization of integral blisk machining, and prediction and compensation method of elastic deformation of efficient and precise machining of thin-walled parts.

[0061] Research on machining technology of super large blisk

[0062] Based on the distribution of processing procedures and the key and difficult problems that may arise in the process, the following processes are mainly analyzed and studied:

[0063] Selection of machine tools for rough turning process and experimental exploration of processing parameters

[0064] The diameter of the blank of this part is greater than 1400mm. According to preliminary calculations, the weight is approximately more than 2.2 tons, which is much heavier than ordinary parts. The following problems are faced during the rough machining process:

[0065] First, whether the lathe worktable can start working normally after bearing the weight of 2.2T blank, whether the load and speed will be affected, it is necessary to find relevant information of the corresponding machine tool, analyze and judge, and choose a more suitable machine tool for processing;

[0066] Second, the part margin is large and the processing cycle is long. In the turning process, the machine tool speed and feed speed parameters are matched. It is necessary to select different parameter groups in advance based on past experience to conduct experiments and optimization, and select the most optimized parameters to ensure processing quality and improve processing efficiency.

[0067] Third, the selection of turning tools. Because titanium alloy materials have a certain viscosity during processing, thermal stress concentration and chip accumulation and tool sticking will occur. Therefore, in the process of selecting turning tools, the heat dissipation, chip removal, processing efficiency and durability of the tool must be considered. If necessary, it is necessary to contact the tool manufacturer to discuss and analyze the tool solution.

[0068] Preliminary implementation plan:

[0069] ① Use the blank blade tip allowance for layered processing, combine the on-site processing experience parameters for up and down floating debugging, use different cutting speeds, feed rates and cutting depths (fix two parameters and change one parameter), and process 9 times in total to collect and establish a processing parameter database;

[0070] ② According to the calculation formulas of cutting speed, feed rate and cutting depth, calculation and analysis are performed respectively:

[0071] Cutting speed v: v= (π*dw*n) / 1000 (m / min), where dw is the diameter of the workpiece surface to be processed (mm), and n is the workpiece speed (r / min);

[0072] Feed speed vf: vf=n*f (mm / min), where n is the spindle speed (r / min) and f is the feed rate (mm / min);

[0073] Cutting depth ap: ap = (dw-dm) / 2 (mm), where dw is the diameter of the workpiece surface to be processed (mm), and dm is the diameter of the workpiece surface that has been processed (mm).

[0074] ③ Establish a curve statistical graph based on the calculated and analyzed data, and select more preferred processing parameters based on the curve graph. The extreme values ​​(high and low points) of the curve in the curve graph correspond to the more preferred processing parameters.

[0075] Research on the distribution and removal technology of rough milling blade profile

[0076] The initial calculated weight of the super-large integral blade disk during rough milling is about 1.8 tons. Combined with the weight of the fixture, it is expected to be more than 2 tons. When rough milling the blade, a heavy disk body will cause a load on the machine tool. The blade of the part is not grooved before rough milling, and the gravity point is concentrated on the blade part. If the disk body margin is too small, the gravity of the milling fixture and the blade part will cause deformation of the insufficiently rigid parts, affecting subsequent processing.

[0077] Considering the processing risks brought by the weight of the parts and the bearing capacity of the five-axis cradle milling, the original traditional processing technology of directly using the five-axis cradle milling was abandoned. A five-axis boring and milling machine was first used to remove part of the processing allowance to reduce the weight of the parts, and then semi-finishing and finishing milling were performed. The ordinary five-axis boring and milling table is flat and can bear heavy parts. The cradle milling table needs to be linked up and down, and heavy parts will be affected by the machine tool load and accuracy.

[0078] Step 1: If Figure 1 As shown, the parts are fixed on the five-axis boring and milling table in a flat manner. Combined with the comprehensive and effective use of machine tools, ordinary large-face milling cutters, corn cob milling cutters, etc. are used. The processing allowance is removed by turning over and equally distributing the processing method. By effectively using the simulation function of the simulation software, program path interference, tool overcutting and other phenomena are predicted in advance, the processing program is planned well, and ordinary machine tools and ordinary tools are used to remove the processing allowance to the maximum extent, thereby achieving the purpose of improving processing efficiency, reducing processing costs, and reducing part weight.

[0079] Step 2: After the parts are processed by different machine tools, the estimated weight will be 1.2T, and then the remaining rough processing allowance will be removed. There are several solutions for rough milling to remove the allowance, which need to be selected by test verification:

[0080] The first method is to use an equidistantly distributed processing solution, that is, after processing the first integral blade disc allowance, the machine tool table rotates 180 degrees to process the second integral blade disc allowance, then rotates 90 degrees to process the third integral blade disc allowance, and the processing is completed in sequence. The advantage of this processing is that the four-axis allowance removal is evenly distributed, the stress and deadweight of the parts are close to a balanced state, and the processing quality control of the parts is convenient. The disadvantage is that the machine tool has a long idling time and low processing efficiency.

[0081] The second method is to use isolation processing and spacer injection molding, that is, to process one blade margin in a clockwise manner, isolate an integral blade disc, and process the third integral blade disc. The processing sequence is 1, 3, 5, 7... After the spacer is processed, the processed cavity is injection molded to increase the rigidity of the adjacent integral blade disc, and then the remaining blade margin is removed. The advantage of this processing is that it can effectively control the vibration and chattering during the processing and increase the rigidity of the integral blade disc. The disadvantage is that there are many processing steps, a long cycle, and high cost.

[0082] The third type: Figure 2As shown in the figure, the "one-to-two" roughing and finishing simultaneous processing scheme that has been applied to other models in the early stage is adopted, that is, the roughing and finishing of two adjacent integral blisks are processed simultaneously. The characteristics of this processing are high processing efficiency and high processing risk. The premise is that it must be combined with the characteristics of the parts, and the deformation of the parts must be mastered to a certain extent and supported by data.

[0083] Which scheme should be used in the processing of the integral blade disk involved? It is necessary to carry out trial processing with the help of rough processing allowance during the rough processing of the specific parts, and use the parts after trial processing for inspection and processing efficiency analysis. According to the inspection results, combined with the advantages and disadvantages of different implementation plans, a comprehensive analysis is carried out to select the most optimized processing scheme.

[0084] Selection of tools: Because the blade chord is long, the tool accessibility is poor. During the processing, the tool cantilever is long and the rigidity is poor. There is tool letting during processing, and the processing accuracy is poor and the processing efficiency is low. Therefore, for the parts involved, it is necessary to discuss the tool design plan with the tool manufacturer according to the part characteristics and customize special tools.

[0085] 3. Research on the distribution and size control process of rough and fine machining allowance

[0086] The size of the rough and fine allowances will affect the control of machining deformation of parts and the improvement of machining efficiency. In previous machining experience, rough machining reserves a 0.5-0.8mm allowance for fine machining, and then the parts are directly machined in place during fine machining. The characteristics of this machining are that the diameter of the blade disk is generally small, the maximum machining diameter is Ø850mm, the blade profile suspension distance is small, the deformation and tool chattering during the machining process are relatively reduced, and the machining difficulty is reduced.

[0087] In order to avoid deformation control and tool vibration during the machining process of parts, combined with the previous experience in machining integral blade disks, it was decided to add semi-finishing on the original basis, that is, when the rough machining allowance is 2mm, a vacuum stress relief heat treatment is carried out, and then the machining is continued. When the allowance is 0.6mm, another vacuum stress relief heat treatment is carried out. This can effectively reduce the residual stress release during the parts machining process and is beneficial to the deformation control of parts machining.

[0088] 4. Research on precision milling blade processing and deformation control technology

[0089] Selection of machining tools. In the conventional blade disc machining in the past, high and low tooth taper milling cutters with independent intellectual property rights were used for machining. Due to the thin overall blade disc, long wingspan, large space cantilever, limited tool machining depth and other factors, it is necessary to customize machining tools of different lengths and different parts based on the specific part machining model. According to the size of the chip allowance and the requirements of the tool cantilever length, the selection of tool materials should be appropriately considered.

[0090] Planning of tool paths. In the precision milling of blade profiles, there are many types of tool paths, including spiral milling, symmetrical spiral milling, reciprocating milling, front and rear edge interpolation milling, and angle scanning milling. How to choose a more optimized tool path strategy requires a combination of the torsional curvature of the blade profile, the complexity of the surface, and the special requirements of the root transition and the front and rear edge transition.

[0091] Application of simulation. Simulation is to simulate the processing of special tools and special processing programs by running machine tool simulation software, so as to intuitively determine the interference, collision, overcutting, smoothness of tool connection and the positions that cannot be processed of the tools and processing programs. According to the simulation results, repeated optimization and modification are carried out until the simulation is successfully passed. Only then can the tools and processing programs be applied in actual processing. The part has complex surfaces, many processing programs and many processing tools. It is necessary to adopt a variety of tool path strategies in combination to ensure the normal processing of the parts. Therefore, a lot of time is needed for program compilation, simulation verification and parameter optimization during the simulation process.

[0092] Selection of machining parameters. Matching the feed speed and rotation speed of the fine milling blade is a key technical difficulty in the implementation of on-site verification. It requires a large amount of on-site machining test data as support, and optimization is carried out on this basis. Different tools process different parts, and the machining parameters need to be specially matched and optimized. The machining tools, machining procedures, and machining parts involved are complex and numerous, and it takes a lot of time to conduct one-by-one experiments and explorations, optimization and improvement; in the case of severe deformation and tool deflection, finite element technology is needed to numerically simulate the cutting process of the integral blade disk, obtain the deformation law of the integral blade disk, and compensate for the deformation of the integral blade disk in the CNC machining program or solid modeling; optimize the mutual balance between process parameters to make them reasonably matched, determine the control domain of cutting process parameters, realize efficient cutting of the integral blade disk and conduct experimental verification, and the selection of parameters needs to be based on the trial machining parameter database, combined with the surface quality of part machining for statistical analysis, and select the best one.

[0093] Treatment of tool joints and root R. For the processing of tool joints and root R of the integral blade disc, it is difficult to make a direct prediction in the simulation software due to the influence of actual factors such as specific tool wear, tool yielding, deformation, etc. It is necessary to reserve allowance for the parts in the specific processing. Through repeated tests and verifications on the allowance, a more reasonable tool joint control method is obtained; the blade root R, as the stress-bearing part and the part where the working stress is concentrated of the integral blade disc, has special requirements on shape and size. Its shape, surface quality, and processing quality of the transition and connection parts affect the fatigue service life of the integral blade disc. Therefore, when processing the root transition R, a lot of time is needed for testing and repeated optimization. At present, the root R is processed by forming tool processing and variable cross-section scanning milling. The specific processing part needs to be tested and verified before judgment can be made.

[0094] When fine milling the blade profile, since most of the excess has been removed, the rigidity of the parts is weak at this time, and they are very easy to vibrate and deform during processing. In order to improve the rigidity of the parts and reduce the occurrence of vibration and deformation, paraffin is used to fill the blades. Paraffin is easy to clean, has good filling effect, is reusable, and does not pollute the cutting fluid. Gypsum, foam glue, shock-proof mud, etc. can also be used as fillers.

[0095] 5. Research on the process technology of fine turning inner spoke plate

[0096] Design and customization of turning tools. The involved blade disc has a compact structure and a double-spoke plate structure. The space on the front face is narrow and the inner circle size of the journal is only ø66mm. Therefore, in the arrangement of processing steps, it is chosen to cut from the rear face with a wider space. The inner circle size of the web is ø134mm, and the deepest part of the deep cavity between the double-spoke plates is ø320mm. The effective overhang of the blade must be greater than 93mm. Taking into full consideration the interference between the rear end face of the blade and the web, the maximum thickness of the base is only 40mm. When turning with an ordinary blade, the blade rigidity is poor due to the elongated cantilever and the small thickness of the base. It vibrates violently during processing and has serious fish scale patterns on the surface. In order to solve the above problems, it is initially considered to design a cantilever turning tool holder with anti-vibration function. The tool mounting part of the holder is designed with different materials to offset the frequency caused by the processing vibration, so as to achieve the effect of shock absorption, thereby improving the surface quality of the turning process.

[0097] Selection of turning parameters. Because the internal machining allowance of the spoke plate is large and the machining space is small, for deep cavity machining, the tool overhang is long and the rigidity is insufficient, and the internal turning machining cannot be directly observed. During machining, in addition to the tool operation programming simulation, the turning machining parameters for different machining parts need to be tested and verified, and the cutting speed, feed rate, and cutting depth need to be optimized and improved. Combined with the verification data analysis, more reasonable machining parameters can be selected.

[0098] Processing technology of super large fan blisk blades

[0099] The research on the processing technology of the integral blade disc of a super-large fan involves many aspects, and it is necessary to comprehensively consider factors such as material properties, processing difficulty, precision requirements, and process flow. In combination with the characteristics of forging materials and the requirements of processing accuracy indicators, the present invention is aimed at: a. Tool selection: The processing of super-large fan blade discs requires the use of high-precision, high-rigidity tools, and the design of the tools should comprehensively consider factors such as material type, processing accuracy requirements, and cutting force; b. Processing technology: The processing technology of super-large fan blade discs is complex, and a detailed processing process needs to be formulated; the processing technology includes; milling, drilling, grinding and other links, and it is necessary to comprehensively consider factors such as tool design schemes, cutting parameters, and processing sequence; c. CNC processing technology: The processing of super-large fan blade discs usually adopts CNC processing technology, which can improve processing accuracy and efficiency. CNC processing technology requires the formulation of accurate processing procedures, including tool paths, cutting parameters, and processing sequences.

[0100] Processing technology of deep cavity of super large fan blade disk

[0101] Combined with the cross-sectional shape of the overall blade disk under study, the length and size of the blades, the surface quality of the spokes, and the shape and size of the deep cavity of the spokes. At the same time, it is necessary to consider the selection of suitable CNC machining machines and determine the possible machining difficulties for subsequent process planning and program formulation. By establishing a CAM model and conducting process analysis, an accurate three-dimensional model is established to help engineers and processing personnel better understand and analyze the design structure and characteristics of the parts, and provide more modification and optimization options, including the machinability of the model, the existence of non-machinable areas, the processing sequence and the corresponding process parameter selection; optimize the tool and tool path: Titanium alloy materials have high hardness, which will cause severe tool wear during processing, so it is necessary to select suitable tools and use scientific tool paths to reduce tool wear. Normally, a multi-tool, multi-process cutting solution is adopted, and each process has a reasonable tool path and cutting parameters; the turning process solution is optimized, and through process analysis and cutting tests, a reasonable turning process flow is gradually determined, and corresponding CNC machining machines and tools are equipped; during the production implementation process, the set process flow is strictly followed, and real-time monitoring and quality inspection of the integral blade disk and deep cavity radial plate processing are carried out to ensure that the processing quality meets the requirements, and at the same time, the process solution is adjusted and optimized in a timely manner to optimize the entire processing flow.

[0102] Ultra-large fan blade tooling design technology

[0103] The design of tooling for the processing of the integral blade disk of the super-large fan needs to be studied in the following aspects: a. Material of tooling: Since the integral blade disk of the super-large fan is large, the material of the tooling needs to have sufficient strength and rigidity to support the blade disk. Usually, it is made of high-strength, wear-resistant alloy steel or stainless steel to ensure its durability and reliability; b. The shape and structure of the tooling: The shape and structure of the tooling need to match the structure of the blade disk and ensure that it is tightly fixed on the processing platform. According to the actual situation of the blade disk, tooling in the form of flat tooling, clamp-type clamps, pneumatic clamps, etc. can be selected. At the same time, it is also necessary to consider the difficulty of processing the deep cavity on the blade disk, and select an adjustable length support mechanism to ensure accuracy and stability; c. The processing accuracy of the tooling: Since the processing accuracy requirements of the blade disk are relatively high, the manufacturing accuracy of the tooling also needs to meet the corresponding requirements. The tooling should be manufactured by CNC machining to ensure processing accuracy and repeatability; d. The operating performance of the tooling: The tooling should be easy to operate and quickly replaced, so that the operator can quickly and accurately clamp and fix the blade disk, and replace the tooling in time. In the process of researching tooling design schemes, it is necessary to fully consider the cost and benefits of tooling, reduce manufacturing costs as much as possible, and at the same time ensure processing efficiency and quality to maximize economic benefits.

[0104] Design technology of blade cutter for super large fan

[0105] The tool design technology for the super-large fan integral blade disk is one of the important technologies for realizing efficient and precise processing of the blade disk. Design of blade shape: In view of the blade characteristics of the super-large fan integral blade disk, the blade needs to adopt a special three-dimensional curved surface geometry. For different processing links, the radius, angle and shape of the blade are reasonably optimized to ensure the processing quality and efficiency; Tool handle strength design: The processing of the super-large fan integral blade disk often requires ultra-long cantilever processing, and the blade disk material is relatively hard, so the tool handle needs to have sufficient strength to avoid breakage or deformation. At the same time, it is also necessary to consider the adjustment of parameters such as the angle and length between the handle and the blade; Blade material selection: The selection of blade materials needs to consider the hardness, wear of the blade material, and the temperature and pressure during processing. The use of materials such as cemented carbide to make blades can meet the requirements of processing strength and wear resistance; Tool surface treatment: The tool will be subjected to greater heat and pressure during the processing process, so the tool surface needs to be specially treated to improve its wear resistance and corrosion resistance. Common surface treatment methods include coating treatment, nitriding treatment, etc. The design technology of the integral blade disc tool needs to be combined with the actual situation and processing requirements, and comprehensively consider various factors such as material, shape, strength, wear, etc. Through innovative solution design and improvement, it is ensured that the tool can complete the blade disc processing efficiently and accurately.

[0106] Cutting technology for complex thin-walled blade-shaped structural parts

[0107] In view of the complex channel shape and boundary constraints of complex thin-walled structures such as integral blades, the machinability analysis algorithm of the complex channel is used to determine the accessible area and cutting direction of the tool; the entire channel is reasonably divided into several processing areas; in each area, the tool axis direction is optimized as a whole; and the five-coordinate "branch-fixed axis" control processing method is used to complete the rough processing of each area.

[0108] For the rough machining of forging blanks made of difficult-to-machine materials, we adopt the new technology of “drilling instead of milling”, plunge milling and rapid milling technology. Through process tests, we optimize the tool parameters and cutting parameters, improve the tool cutting state, and enhance the machining stability and cutting efficiency.

[0109] In order to solve the residual stress caused by large forging blanks with large removal amount and the deformation of the integral blade disk structure caused by it, the methods of clamping optimization + rough machining + heat treatment + stabilization treatment + benchmark measurement + benchmark repair are adopted to realize the comprehensive control of rough machining deformation compensation and material structure performance, effectively reduce the allowance of the integral blade disk in the later processing, and avoid re-heat treatment during the integral blade disk processing stage.

[0110] Aiming at the problems of machine tool servo delay in five-axis high-speed finishing of complex thin-walled integral blisk, multi-body dynamics optimization and error compensation of five-axis high-speed machining tool trajectory are carried out to ensure the stability of the thin-walled integral blisk machining process, surface machining accuracy and surface quality.

[0111] Research on cutting technology of complex thin-walled structural parts Figure 3 As shown, it includes feature modeling, cutting parameter optimization, deformation control and chatter suppression, and CNC programming. The process solution is obtained through feature modeling, cutting parameter optimization, deformation control and chatter suppression, and then CNC machining program compilation, digital simulation and physical simulation, overall structural parts machining and inspection analysis are carried out. If the digital simulation and physical simulation, overall structural parts machining and inspection analysis meet the design requirements, the data are entered into the cutting parameter library and the tool parameter library. If the digital simulation and physical simulation, overall structural parts machining and inspection analysis do not meet the design requirements, process tests are carried out.

[0112] Chatter Suppression Technology for High-speed Milling of Thin-walled Blade Parts

[0113] During the machining of mechanical parts, the machine tool spindle-tool and thin-walled workpiece vibrate, which reduces the surface quality of the workpiece. In particular, when ultra-high-speed machine tools are used to machine thin-walled structural parts, the chatter is more serious. Therefore, the chatter in the cutting process must be effectively controlled. In the field of cutting chatter control, predictive control is the most active and effective control method, and how to accurately and timely predict chatter is the premise of predictive control. However, most of the existing chatter prediction methods are based on checking whether there are periodic components in the vibration signal, and do not reflect the essential characteristics of cutting chatter. The prediction reliability is not high and it is difficult to promote and apply. Therefore, the present invention proposes a new chatter prediction method that can reflect the essential characteristics of cutting chatter.

[0114] Research plan such as Figure 4 As shown in the figure, different methods are used in combination to suppress the chatter phenomenon in the cutting process of thin-walled parts during the milling process, including structural improvement and optimization design methods by increasing the stiffness and damping of the machine tool structure; methods using vibration absorbers or additional vibration-absorbing devices; control methods for adjusting cutting parameters, mainly online adjustment of cutting parameters such as spindle speed, feed rate, cutting depth, tool angle, etc., which essentially changes cutting stiffness and cutting damping; selection of suitable tools to eliminate chatter in the milling process; and reasonable clamping methods and appropriate increase of auxiliary supports to improve the stiffness of the workpiece system and suppress chatter generated during the milling of thin-walled parts.

[0115] This invention will also focus on the vibration suppression method based on the design of non-uniform allowance for finishing of thin-walled parts, including modeling and prediction of milling force, finite element calculation of machining dynamic behavior, optimization design of semi-finishing allowance distribution of integral blade, generation of spiral tool position trajectory and process test correction. Figure 5 shown.

[0116] 1) According to the machining experience and the CAD model of the blisk, determine the initial cutting parameters (such as cutting width, feed speed and spindle speed, etc.) and the initial distribution of the semi-finishing allowance of the blisk.

[0117] 2) When machining thin-walled parts, the actual cutting state of the tool changes due to machining deformation and vibration behavior, forming an iterative calculation process between the cutting force and the system dynamic response. System vibration causes changes in instantaneous chip thickness, and the cutting force changes accordingly. The change in chip thickness can be determined by the cutting-in angle and cutting-out angle of the cutter tooth micro-segment; in turn, the instantaneous chip thickness is a function of the machining deformation of thin-walled parts and depends on the cutting force. First, the cutting force model calculates the nominal cutting force based on the initial cutting parameters at each tool position point, and inputs it into the finite element model to simulate the dynamic cutting process; secondly, based on the machining dynamic information obtained by the finite element calculation, the contact conditions between the cutter tooth micro-element and the workpiece are updated, fed back to the cutting force model, and recalculated. When the difference between the two predicted cutting force magnitudes meets the set tolerance requirements, the iterative process ends.

[0118] 3) According to the calculation results output from the finite element model, the dynamic response characteristics of the thin-walled integral blade disk in the actual processing process are analyzed, and the semi-finishing allowance distribution state of the blade body is optimized to improve the rigidity distribution of the blade tip and leading and trailing edge areas during the finishing process. The spiral tool position trajectory is used to preferentially remove the machining allowance in the blade tip area. At the same time, by optimizing and controlling the tool axis vector direction at the tool position point on the tool path, the force state of the tool and the integral blade disk is adjusted so that the cutting force is mainly along the tool axis direction and the blade body tangent plane direction (i.e., the direction with the best rigidity). In this way, a large iterative cycle process is formed between the cutting force model, the finite element model, the allowance distribution optimization design model, and the spiral tool path generation model.

[0119] 4) The final output is the optimized distribution of the semi-finishing allowance of the integral blade, the optimized tool trajectory, and the optimized cutting parameters. To determine and optimize the cutting stability area, the experimental modal analysis method is used to identify the modal parameters of the machine tool-tool-integral blade system structure, determine the size of the dynamic component of the instantaneous cutting thickness caused by vibration deformation, and establish the milling dynamics equation. In the frequency domain, the harmonic function and frequency response function are used to describe the vibration behavior at the chatter frequency, and then the milling stability limit diagram is drawn to determine the stability and instability areas of the cutting system, thereby suppressing chatter.

[0120] Residual stress and deformation control method for high-efficiency precision machining of thin-walled blade parts

[0121] The main aspects of residual stress analysis will be considered from three aspects: residual stress caused by the mechanical force of cutting, residual stress caused by thermal stress of cutting and residual stress caused by phase change. By simulating the machining process with numerical simulation technology before machining, analyzing the machining process, determining the influence of various parameters on the residual stress of parts, and predicting the deformation and cracking of complex parts during machining. Research on the optimal machining scheme with the goal of controlling residual stress deformation, using machining technology based on residual stress symmetry, optimizing clamping and positioning, etc., to weaken the deformation caused by residual stress during and after machining, thereby controlling the machining accuracy of parts. Research scheme for residual stress deformation control in efficient and precise machining of thin-walled parts Figure 6 shown.

[0122] Electromagnetic coupling processing technology for equalizing residual stress in precision milling of integral blade disk

[0123] The research plan for this technical problem is as follows Figure 7 As shown in the figure, a single TC17 blade specimen with the weight of the entire blade disk was selected as the research object.

[0124] ① Computer simulation: Establish a three-dimensional model of the electromagnetic coupling treatment TC17 blade disk test piece. Through the COMSOL simulation software, input different electromagnetic coupling treatment process parameters, analyze and study the corresponding relationship between the temperature gradient change, Lorentz force, current density, stress-strain and residual stress of the material, and specify the process plan for electromagnetic coupling treatment of the TC17 blade disk test piece according to the simulation results.

[0125] ② Experimental research: Design and prepare special tooling and fixtures for electromagnetic coupling treatment of blade disk test pieces; use different electromagnetic coupling treatment process parameters to treat the test pieces; select key parts of the blade for multi-point calibration, carry out quasi-in-situ residual stress detection tests, use X-ray diffraction residual stress non-destructive detection method to detect residual stress at the calibrated positions, and compare and analyze the absolute value of residual stress and the change law of residual stress direction before and after electromagnetic coupling treatment; measure the resistance value and magnetic saturation intensity of the blank before and after electromagnetic coupling treatment; study the influence of electromagnetic coupling external field treatment process parameters on the residual stress of TC17 blade disk specimen processing based on experimental results; establish process specifications for equalizing the residual stress of TC17 blade disk specimen processing using electromagnetic coupling treatment technology.

[0126] Prediction and compensation method of elastic deformation in high-efficiency precision machining of thin-walled blade-shaped parts

[0127] Prediction and compensation of machining elastic deformation error based on finite element simulation method Figure 8 As shown in the figure, at any tool position, according to the initial processing conditions, the flexible cutting force (F x , Fy , F z ) and processing deformation (u x ,u y ,u z ) in a "balanced" state. After the tool path is corrected, the tool is closer to the theoretical cutting position, and the actual cutting width and cutting force are larger than the predicted values ​​of the last iteration. As a result, the tool and the workpiece will be in different equilibrium positions. In this way, if the tool path is only compensated once, the cutter teeth still cannot reach the cutting position required by the process. Instead, the contact conditions at the tool position must be updated according to the machining deformation information, and the cutting force and machining deformation must be recalculated to correct and compensate the tool path in a cyclic and progressive manner.

[0128] The above embodiments are only preferred embodiments of the present invention and are not limitations of the technical solutions of the present invention. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present invention.

Claims

1. A method for processing an integral blade disk, characterized in that: The processing route of the integral blade disk includes: blank, CNC rough turning, two-step CNC rough milling, vacuum heat treatment, benchmark repair, semi-finishing blade milling, semi-finishing turning, secondary vacuum heat treatment, secondary benchmark repair, fine milling blade, fine turning, polishing, clamp repair, appearance inspection, fluorescent inspection, shot peening, vibration finishing, spraying, static balancing, final inspection, and warehousing; In the CNC rough turning process, the blank blade tip allowance is used for layered processing, and the parameters are adjusted up and down based on the on-site processing experience. Different cutting speeds, feed rates and cutting depths are used under the premise of fixing two parameters and changing one parameter. The processing is divided into 9 times, and the processing parameter database is collected and established; According to the calculation formulas of cutting speed, feed rate and cutting depth, calculation and analysis are performed respectively, and a curve statistical graph is established based on the calculation and analysis data, and the optimal processing parameters are selected based on the curve graph. The extreme value of the curve in the curve graph corresponds to the optimal processing parameter; During the rough milling process, the parts are fixed on the five-axis boring and milling table in a flat manner. Combined with the comprehensive and effective use of machine tools, ordinary large-face milling cutters and corn cob milling cutters are used to remove the machining allowance by turning over and evenly distributing the machining. By effectively using the simulation function of the simulation software, program path interference and tool overcutting phenomena are predicted in advance, and the machining program is planned well. Ordinary machine tools and ordinary tools are used to remove the machining allowance to the maximum extent. After removing the machining allowance from the parts, remove the remaining rough machining allowance; When the rough machining allowance is 2mm, vacuum heat treatment is carried out, and when the allowance is 0.6mm, secondary vacuum heat treatment is carried out; When fine milling the blade shape, use paraffin to fill the blade. You can also use gypsum, foam glue, and anti-vibration mud to fill the blade. During the rough milling process, the rough machining allowance is used to perform test machining on specific parts. The parts after the test machining are used for testing and machining efficiency analysis. One of the following solutions is selected based on the test results: The first method is to use a symmetrically distributed processing scheme, that is, when the first blisk margin is processed, the machine tool table rotates 180 degrees to process the second blisk margin, then rotates 90 degrees to process the third blisk margin, and the processing is completed in sequence; The second method is to use isolation processing and spacer injection molding, that is, after processing one inter-blade margin clockwise, isolate an integral blade disk and process the third integral blade disk. The processing sequence is similar. After the spacer is processed, the processed cavity is injection molded to increase the rigidity of the adjacent integral blade disk, and then the remaining inter-blade margin is removed. The third method: adopting a one-to-two roughing and finishing synchronous processing scheme, that is, the roughing and finishing of two adjacent blisks are processed synchronously; The processing method also includes a chatter suppression method based on the non-uniform allowance design of thin-walled parts involved in the semi-finishing milling of blade profiles and semi-finishing turning in the integral blade disk processing route, including: According to the machining experience and the CAD model of the blisk, the initial cutting parameters including cutting width, feed speed and spindle speed and the initial distribution state of the semi-finishing allowance of the blisk are determined; When machining thin-walled parts, the cutting force model first calculates the nominal cutting force based on the initial cutting parameters at each tool position, and inputs it into the finite element model to simulate the dynamic cutting process. Based on the machining dynamic information obtained by the finite element calculation, the contact conditions between the cutter tooth microelement and the workpiece are updated and fed back to the cutting force model for recalculation. When the difference between the two predicted cutting force magnitudes meets the set tolerance requirements, the iterative process ends. According to the calculation results output from the finite element model, the dynamic response characteristics of the thin-walled integral blade disk in the actual machining process are analyzed, and the semi-finishing allowance distribution state of the blade body is adjusted to improve the rigidity distribution of the blade tip and the leading and trailing edge areas during the finishing process. The spiral tool position trajectory is used to preferentially remove the machining allowance in the blade tip area. At the same time, by optimizing and controlling the tool axis vector direction at the tool position point on the tool path, the force state of the tool and the integral blade disk is adjusted so that the cutting force is mainly along the tool axis direction and the blade body tangent plane direction, that is, the direction with the best rigidity. A large iterative cycle process is formed between the cutting force model, the finite element model, the allowance distribution optimization design model and the spiral tool trajectory generation model. The final output result is the optimized distribution state of the semi-finishing allowance of the integral blade, the optimized tool trajectory and the optimized cutting parameters. The cutting stability area is determined and optimized. The modal parameters of the machine tool, tool and integral blade system structure are identified by using the experimental modal analysis method. The size of the dynamic component of the instantaneous cutting thickness caused by vibration deformation is determined, and the milling dynamics equation is established. The harmonic function and frequency response function are used in the frequency domain to describe the vibration behavior at the chatter frequency, and then the milling stability limit diagram is drawn to determine the stability and instability areas of the cutting system, thereby suppressing chatter.

2. The method for processing an integral blade disk according to claim 1, characterized in that: In the fine milling of the blade profile, the tool path strategy needs to be selected and matched based on the torsional curvature of the blade profile, the complexity of the surface, and the special requirements of the root transition and the leading and trailing edge transition. The tool paths include: spiral milling, symmetrical spiral milling, flipping and reciprocating milling, leading and trailing edge interpolation milling, and scanning milling with an inclination angle.

3. The method for processing an integral blade disk according to claim 1, characterized in that: The processing method also includes the cutting method of complex thin-walled structural parts involved in the precision milling of blade profiles in the integral blade processing process route, including: In view of the complex channel shape and boundary constraints of the complex thin-walled structure of the integral blade disk, the machinability analysis algorithm of the complex channel is used to determine the reachable area and cutting direction of the tool, and the entire channel is divided into multiple processing areas. The tool axis direction is optimized as a whole in each area, and the five-coordinate branch fixed axis control processing method is used to complete the rough processing of each area; For the rough machining of forging blanks made of difficult-to-machine materials, new processes such as drilling instead of milling, plunge milling, and rapid milling are adopted, and tool parameters and cutting parameters are adjusted through process tests; In view of the residual stress generated by large forging blanks with large removal amount and the deformation of the integral blade disk structure caused by it, the clamping optimization, rough machining, heat treatment, stabilization treatment, benchmark measurement and benchmark repair methods are adopted to achieve comprehensive control of rough machining deformation compensation and material structure performance, reduce the allowance of the integral blade disk in the later processing, and avoid re-heat treatment during the integral blade disk processing stage; Aiming at the problem of machine tool servo delay in five-axis high-speed finishing of complex thin-walled integral blisk, the stability of the thin-walled integral blisk machining process, surface machining accuracy and surface quality are guaranteed through multi-body dynamics optimization and error compensation of the five-axis high-speed machining tool trajectory.

4. The method for processing an integral blade disk according to claim 3, characterized in that: The cutting method of complex thin-walled structural parts includes feature modeling, cutting parameter optimization, deformation control and chatter suppression, and CNC programming. The process solution is obtained through feature modeling, cutting parameter optimization, deformation control and chatter suppression, and then CNC machining program compilation, digital simulation and physical simulation, overall structural parts machining and inspection analysis are carried out. If the digital simulation and physical simulation, overall structural parts machining and inspection analysis meet the design requirements, the data are entered into the cutting parameter library and tool parameter library. If the digital simulation and physical simulation, overall structural parts machining and inspection analysis do not meet the design requirements, process tests are carried out.

5. The method for processing an integral blade disk according to claim 1, characterized in that: The processing method also includes a method for suppressing chatter in high-speed milling of thin-walled parts involved in fine milling of blade profiles in the integral blade disc processing process route, including: Increase the rigidity and damping of the machine tool structure and use vibration absorbers or additional vibration elimination devices; Adjust the control method of cutting parameters, online adjust the cutting parameters including spindle speed, feed rate, cutting depth, tool angle, etc., and change the cutting stiffness and cutting damping; Adjust or replace cutting tools to eliminate chatter during milling; Adjust the clamping method and appropriately increase auxiliary supports to improve the rigidity of the workpiece system and suppress the chatter generated during the milling of thin-walled parts.

6. The method for processing an integral blade disk according to claim 1, characterized in that: The processing method also includes a method for controlling residual stress and deformation of thin-walled parts involved in precision milling of blades in the integral blade processing process, including: By using numerical simulation technology to simulate the machining process before machining, the machining process is analyzed, the influence of various parameters on the residual stress of parts is determined, the deformation and cracking of complex parts during machining are predicted, and the optimization machining plan with the goal of controlling residual stress and deformation is studied. The machining process based on residual stress symmetry is adopted and the clamping positioning is optimized to weaken the deformation caused by residual stress during and after machining, and control the machining accuracy of parts.

7. The method for processing a blisk according to claim 1, characterized in that: The processing method also includes an electromagnetic coupling processing method for equalizing residual stress of the integral blade disk processing involved in the precision milling of the blade profile in the integral blade disk processing process route, including: A single TC17 blade specimen in the integral blisk was selected as the research object; Computer simulation: Establish a three-dimensional model of the electromagnetic coupling treatment TC17 blade disk test piece. Use COMSOL simulation software to input different electromagnetic coupling treatment process parameters, analyze and study the corresponding relationship between the temperature gradient change, Lorentz force, current density, stress strain and residual stress of the material, and specify the process plan for electromagnetic coupling treatment of the TC17 blade disk test piece based on the simulation results; Experimental research: Design and prepare special tooling and fixtures for electromagnetic coupling treatment of blade disk test pieces, use different electromagnetic coupling treatment process parameters to treat the test pieces, select key parts of the blade for multi-point calibration, carry out quasi-in-situ residual stress detection tests, use X-ray diffraction residual stress non-destructive detection method to detect residual stress at the calibrated positions, compare and analyze the absolute value of residual stress and the change law of residual stress direction before and after electromagnetic coupling treatment, measure the resistance value and magnetic saturation intensity of the blank before and after electromagnetic coupling treatment, and study the influence of electromagnetic coupling external field treatment process parameters on the residual stress of TC17 blade disk specimen processing based on the experimental results, and establish the process specifications for equalizing the residual stress of TC17 blade disk specimen processing using electromagnetic coupling treatment technology.

8. The method for processing a blisk according to claim 1, characterized in that: The processing method also includes a method for predicting and compensating the elastic deformation of thin-walled parts involved in the precision milling of blades in the integral blade processing route, including: At any tool position, according to the initial processing conditions, the flexible cutting force (F x , F y , F z ) and processing deformation (u x ,u y ,u z ), after the tool trajectory is corrected, the tool is closer to the theoretical cutting position, the actual cutting width and cutting force are larger than the predicted values ​​of the last iteration. As a result, the tool and the workpiece will be in different equilibrium positions. If the tool trajectory is compensated only once, the cutter teeth still cannot reach the cutting position required by the process. Instead, the contact conditions at the tool position must be updated according to the machining deformation information, and the cutting force and machining deformation must be recalculated to correct and compensate the tool trajectory in a cyclic and progressive manner.

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