A method for accurately positioning the tenon groove of a turbine disc for a five-axis CNC broaching machine

Abstract

The present invention belongs to the field of machining technology, and specifically relates to a method for accurately positioning a turbine disc tenon groove for a five-axis CNC broaching machine, comprising the following steps: S1, constructing a broaching force model, carrying out a broaching force test, and obtaining the turbine disc tenon groove broaching force coefficients in the x, y, and z directions, respectively, to establish a single-tooth broaching force model; then constructing a multi-tooth broaching force model based on the single-tooth cutting force model, S2, mechanical deformation analysis, and obtaining the workpiece deformation according to the cutting force calculation; then using a laser to measure the displacement change of the tenon groove cutting point; and based on the values ​​of multiple groups of workpiece deformation and displacement change, performing linear equation fitting to obtain the corresponding linear equation; S3, when using a broaching machine for processing, calculating the cutting force based on the broaching force model, and then applying the corresponding cutting force load on the tenon groove broaching machine finite element model to obtain the deformation in the x, y, and z directions, and then calculating the actual deformation according to the linear equation in S2 to obtain accurate positioning coordinates.

Description

Technical Field

[0001] The invention relates to the technical field of turbine disc tenon and groove broaching machine manufacturing, and in particular to a turbine disc tenon and groove accurate positioning method for a five-axis numerically controlled broaching machine. Background Art

[0002] As a key core component of aircraft engines, turbine disks are responsible for installing and fixing turbine blades and transmitting power. In extremely harsh working environments such as high temperature, high pressure, and high speed, turbine disks need to withstand complex and variable loads, which requires that their materials must have excellent performance. High-temperature alloys or titanium alloys are usually selected to ensure reliability and durability under extreme working conditions. The design and manufacturing process level of turbine disks plays a vital role in the overall performance of the engine. Its precision and quality are directly related to the thrust-to-weight ratio, reliability, and safety of the engine. Among them, the machining accuracy of the tenon and groove of the turbine disk is particularly critical, which directly determines the performance of the impeller. Once the tenon and groove machining accuracy is insufficient, it may cause a series of problems such as impeller vibration and fatigue damage, which in turn affects the normal operation and service life of the engine.

[0003] In the prior art, a broaching machine is generally used to process the tenon groove of a turbine disc. However, the broaching force between the workpiece and the tool during the processing will cause the tool movement position and the workpiece clamping position to change, which will significantly reduce the processing accuracy of the tenon groove. To solve this problem, when a broaching machine is used to process the tenon groove of a turbine disc, a corresponding method or system is generally required for precise positioning. Therefore, the present application aims to provide a method and system for accurately positioning the tenon groove of a turbine disc for a five-axis CNC broaching machine to improve processing accuracy and efficiency. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a method for accurately positioning the tenon groove of a turbine disc for a five-axis CNC broaching machine.

[0005] The movements of the broaching machine targeted by this application can be divided into the following movements:

[0006] (1) Drive the workpiece to move in the X-axis, that is, horizontally;

[0007] (2) Rotational motion around the Y axis (often called the A axis) controlled by the C-shaped cradle of the broaching machine;

[0008] (3) The movement of the broaching machine's turntable rotating around the Z axis;

[0009] (4) Movement in the Y-axis direction (front and back direction) controlled by a moving stage.

[0010] The technical solution of the present invention is: a method for accurately positioning the tenon groove of a turbine disc for a five-axis CNC broaching machine; comprising the following steps:

[0011] S1. Constructing the broaching force model

[0012] S1-1, establish a single tooth broaching force model;

[0013] The broaching force test was carried out. The workpiece was made of the same material as the tenon workpiece, and the tool was a single-tooth broach. The angle and material of the tool were consistent with those of the broach for broaching the turbine disk tenon. Based on the test results, the turbine disk tenon broaching force coefficients in the x, y, and z directions were obtained to establish a single-tooth broaching force model.

[0014] S1-2, establish a multi-tooth broaching force model;

[0015] The tool adopts a multi-tooth broach. Based on the single-tooth broaching force model in S1-1, a multi-tooth broaching force model is constructed to calculate the broaching force of the turbine disc tenon groove in the x, y, and z directions when the multi-tooth broach is cutting.

[0016] S2. Mechanical deformation analysis

[0017] Conduct mechanical deformation analysis on turbine disc mortise and tenon broaching machine, establish three-dimensional coordinate system, construct finite element model, set boundary conditions; conduct static analysis under cutting load under common mortise and tenon broaching process parameters; including:

[0018] S2-1, calculate the deformation of the workpiece based on the cutting force;

[0019] S2-2, placing the workpiece deformation obtained in S2-1 into a three-dimensional coordinate system, and using a laser to measure the displacement change of the mortise and tenon cutting point;

[0020] S2-3, repeating steps S2-1 and S2-2 to obtain multiple sets of values ​​of workpiece deformation and displacement variation;

[0021] S2-4, performing linear equation fitting based on multiple sets of values ​​of workpiece deformation and displacement variation to obtain a corresponding linear equation;

[0022] S3, Positioning compensation

[0023] When using a five-axis CNC broaching machine to process different types of mortise and tenon grooves, the cutting force is first calculated based on the broaching force model constructed in S1. The calculated cutting force load is applied to the finite element model of the mortise and tenon broaching machine to obtain the workpiece deformation. Then, the displacement change of the corresponding cutting point is calculated based on the linear equation in S2. The displacement changes in the three directions are set as When machining the tenon groove of a turbine disk, if the initial positioning coordinates of the tenon groove are , then the accurate positioning coordinates after considering cutting deformation are: ; ; .

[0024] Further, in step S1-1, the following operations are included: according to the cutting principle, the mortise and tenon broaching force is divided into the top cutting edge cutting force and the side cutting edge cutting force, and the turbine disc mortise and tenon broaching force in the x direction is assumed to be: (1), where is the cutting force of the top cutting edge, is the cutting force of the side cutting edge;

[0025] (2), where It is the tooth rise of the broach tooth top, which is equivalent to the cutting depth of the tooth top; is the width of the broach teeth, is the area cutting force coefficient of the top cutting edge, is the cutting force coefficient of the length of the top cutting edge;

[0026] (3), where It is the tooth lift of the broach tooth side, which is equivalent to the cutting depth of the tooth side. The length of the broach tooth side involved in cutting, is the area cutting force coefficient of the cutting edge on the tooth side, is the cutting force coefficient of the cutting edge length on the tooth side.

[0027] Furthermore, step S1-1 includes the following operations: using a single-tooth broach, performing cutting tests with different tooth top widths, tooth lifts, and different tooth side tooth lifts and widths, and calculating the cutting force coefficient in the x direction based on formulas (1)-(3).

[0028] Furthermore, there are 4 unknowns in the above formula, and at least 4 sets of equations are required to find the corresponding coefficients. Considering the actual cutting process and matching parameter group of the mortise and tenon groove, the tooth lift of the broaching tool tooth top and the tooth side is 0.070~0.100 mm, the tooth top cutting width (cutting edge length) is 1~2.8 mm, and the width (cutting edge length) of the broaching tool side is 1-3 mm. Therefore: in step S1-1, the following operations are performed: keep the tooth lift and cutting width of the broaching tool tooth top unchanged, which are respectively 0.08 mm and 2.5 mm, set the tooth lift of the broaching tool tooth side to 0.07, 0.08, 0.09, 0.10 mm, respectively, and set the cutting width (i.e., cutting edge length) of the broaching tool side to 1, 1.5, 2, 2.5 mm, respectively. According to the test results, the relevant cutting force coefficient of the broaching tool tooth side can be calculated. Each cutting force coefficient has multiple values, and the average of the multiple values ​​of the cutting force coefficient is taken.

[0029] In step S1-1, the following operations are performed: the tooth lift and cutting width on the side of the broach are kept unchanged, and are set to 0.08 mm and 2 mm respectively, and the tooth lift of the broach tooth top is set to 0.07, 0.08, 0.09, and 0.10 mm respectively, and the cutting width (i.e., cutting edge length) of the broach tooth top is set to 1, 1.5, 2, and 2.5 mm respectively. The relevant cutting force coefficient of the broach tooth top can be calculated based on the test results. Each cutting force coefficient has multiple values, and the average of the multiple values ​​of the corresponding cutting force coefficient is taken to obtain the relevant cutting force coefficient in the x direction.

[0030] Furthermore, in step S1-1, the cutting force coefficients in the y and z directions are calculated by the same method as that in the x direction. The single tooth broaching force model in the y and z directions is constructed:

[0031] The turbine disc mortise and tenon broaching force in the y direction is: , , ;

[0032] in is the cutting force of the top cutting edge, is the cutting force of the side cutting edge, It is the tooth rise of the broach tooth top, which is equivalent to the cutting depth of the tooth top. is the width of the broach teeth, is the area cutting force coefficient of the top cutting edge, is the cutting force coefficient of the top cutting edge length, It is the tooth lift of the broach tooth side, which is equivalent to the cutting depth of the tooth side. The length of the broach tooth side involved in cutting, is the area cutting force coefficient of the cutting edge on the tooth side, is the cutting force coefficient of the length of the cutting edge on the tooth side.

[0033] Turbine disc mortise and tenon broaching force in z direction: , , ;

[0034] in is the cutting force of the top cutting edge, is the cutting force of the side cutting edge, It is the tooth rise of the broach tooth top, which is equivalent to the cutting depth of the tooth top. is the width of the broach teeth, is the area cutting force coefficient of the top cutting edge, is the cutting force coefficient of the top cutting edge length, It is the tooth lift of the broach tooth side, which is equivalent to the cutting depth of the tooth side. The length of the broach tooth side involved in cutting, is the area cutting force coefficient of the cutting edge on the tooth side, is the cutting force coefficient of the length of the cutting edge on the tooth side.

[0035] Further, in step S1-2, the tooth lift of the top of the cutter tooth, the width of the top of the cutter tooth, the tooth lift of the side of the cutter tooth, and the cutting width of the side of the cutter tooth are respectively: ; Then the broaching force of a single tooth of the broach in the x direction is: , , ;

[0036] is the cutting force of the top cutting edge of a single tooth of the broach in the x direction; It is the cutting force of the side cutting edge of a single tooth of the broach in the x direction.

[0037] The broaching force of a single tooth in the y direction is: , , ;

[0038] is the cutting force of the top cutting edge of a single tooth of the broach in the y direction; is the cutting force of the side cutting edge of a single tooth of the broach in the y direction.

[0039] The broaching force of a single tooth in the z direction is: , , ,in is the cutting force of the top cutting edge of a single tooth of the broach in the z direction; is the cutting force of the side cutting edge of a single tooth of the broach in the z direction;

[0040] Assume that when the mortise and tenon are broached stably, there are n teeth on the tool involved in cutting, n is a natural number, and the tool is generally provided with 3-4 teeth; then during stable broaching, the broaching forces in the x, y, and z directions are respectively: ; ; .

[0041] Further, in step S2-1, the following operations are included: referring to the cutting force calculated by the broaching force model in step S1, and using the same mortise and tenon broaching machine constraint conditions, the workpiece deformation in the x, y, and z directions is obtained and set as: .

[0042] Furthermore, in step S2-2, the following operations are included: using laser to measure the displacement change of the mortise and tenon cutting point in the x, y, and z directions, which are respectively set as: , the displacement change can be obtained by comparing the positions of the cutting points before and after cutting, that is: , , , where: x1, x2 are the position coordinates of the cutting point in the x direction after and before cutting respectively;

[0043] y1, y2 are the position coordinates of the cutting point in the y direction after and before cutting respectively;

[0044] z1 and z2 are the position coordinates of the cutting point in the z direction after and before cutting respectively.

[0045] Furthermore, in step S2-3, different process parameters are used to conduct experiments to obtain multiple sets of different values ​​of workpiece deformation and displacement variation, and at least two sets of values ​​of workpiece deformation and displacement variation under different process parameters must be obtained.

[0046] Furthermore, in step S2-4, the linear equation is: , , ;

[0047] in, They are the weights and biases in the corresponding linear directions, respectively, and can be obtained by the workpiece deformation in the x, y, and z directions calculated under multiple sets of different process parameters and the cutting point displacement deformation obtained by laser measurement.

[0048] Compared with the prior art, the present invention has the following beneficial effects: a method for accurately positioning a turbine disc tenon and groove for a five-axis CNC broaching machine proposed in the present invention; first, a broaching force test is carried out, and the workpiece during the test is made of the same material as the tenon and groove workpiece, and the angle and material of the tool are also consistent with the broaching tool for broaching the turbine disc tenon and groove, and a broaching force model is obtained according to the test results; then, through mechanical deformation analysis, a linear correlation between the theoretical deformation of the workpiece and the realized displacement change of the cutting point under a certain broaching force is obtained; finally, through the broaching force model and the corresponding linear equation, the accurate positioning coordinates of the tenon and groove can be quickly calculated, thereby significantly improving the machining accuracy and efficiency of the tenon and groove broaching machine. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is described below in conjunction with specific embodiments. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of concepts in the present invention.

[0050] Example 1

[0051] The movement of the broaching machine targeted by this application can be divided into the following movements in turn:

[0052] (1) Drive the workpiece to move in the X-axis, that is, horizontally;

[0053] (2) Rotational motion around the Y axis (often called the A axis) controlled by the C-shaped cradle of the broaching machine;

[0054] (3) The movement of the broaching machine's turntable rotating around the Z axis;

[0055] (4) Movement in the Y-axis direction (front and back direction) controlled by the moving stage.

[0056] The method for accurately positioning the tenon groove of a turbine disc for a five-axis CNC broaching machine of this embodiment comprises the following steps:

[0057] S1. Constructing the broaching force model

[0058] S1-1. Establishing single tooth broaching force model

[0059] The broaching force test was carried out to obtain the cutting force coefficient of the tenon and groove broaching. The workpiece is made of the same material as the tenon and groove workpiece, and the tool is a single-tooth broach. The angle and material of the tool are the same as those of the broaching tool for broaching the turbine disk tenon and groove. According to the cutting principle, the tenon and groove broaching force is divided into the top cutting edge cutting force and the side cutting edge cutting force. Assume that the turbine disk tenon and groove broaching force in the x direction is: (1), where is the cutting force of the top cutting edge, is the cutting force of the side cutting edge;

[0060] (2), where It is the tooth rise of the broach tooth top, which is equivalent to the cutting depth of the tooth top. is the width of the broach teeth, is the area cutting force coefficient of the top cutting edge, is the cutting force coefficient of the length of the top cutting edge;

[0061] (3), where It is the tooth lift of the broach tooth side, which is equivalent to the cutting depth of the tooth side. The length of the broach tooth side involved in cutting, is the area cutting force coefficient of the cutting edge on the tooth side, is the cutting force coefficient of the length of the cutting edge on the tooth side.

[0062] The broaching force test of single-tooth broach side pulling is adopted, that is, a broach is used to realize cutting test with different tooth top width, tooth lift and different tooth side tooth lift and width, so as to calculate the above-mentioned related cutting force coefficient.

[0063] When this test method is used, the cutting force equation is formula (1)-(3); by adjusting the upper and lower heights and the left and right distances of the broach teeth, the cutting depth and width of the broach can be adjusted to obtain the tooth lift and width of different tooth tops and the tooth lift and width of different tooth sides.

[0064] There are 4 unknowns in the above cutting force equation, and at least 4 sets of equations are needed to find the relevant coefficients.

[0065] Taking into account the actual cutting process of the mortise and tenon and the supporting parameter group, the tooth lift of the broach tooth top and the tooth side is 0.070~0.100 mm, the tooth top cutting width (cutting edge length) is 1~2.8 mm, and the width of the broach tooth side (cutting edge length) is 1-3 mm.

[0066] In this embodiment, the tooth lift and cutting width of the broach tooth top are first kept unchanged at 0.08 mm and 2.5 mm respectively, and the tooth lift on the broach tooth side is set to 0.07, 0.08, 0.09, and 0.10 mm respectively, and the cutting width (cutting edge length) on the broach tooth side is set to 1, 1.5, 2, and 2.5 mm respectively. According to the test results, the cutting force coefficient on the broach tooth side can be calculated, where each cutting force coefficient has multiple values, and the average of the multiple values ​​of the cutting force coefficient is taken.

[0067] Secondly, keep the tooth lift and cutting width of the broach tooth side unchanged, take 0.08 mm and 2 mm respectively, set the tooth lift of the broach tooth top to 0.07, 0.08, 0.09, 0.10 mm respectively, and the cutting width (cutting edge length) of the broach tooth top to 1, 1.5, 2, 2.5 mm respectively. According to the test results, the cutting force coefficient of the broach tooth top can be calculated, where each cutting force coefficient has multiple values, and the average of the multiple values ​​of the cutting force coefficient is taken. Then the total cutting force coefficient in the x direction is obtained.

[0068] The cutting force coefficient of broaching is determined through the above operations, and then the broaching force model of the mortise and tenon in the x direction is established according to formulas (1)-(3).

[0069] Similarly, the cutting forces in the y and z directions are collected, the cutting force coefficients in the y and z directions are obtained, and the single tooth broaching force model in the y and z directions is constructed. The specific description is as follows: The turbine disc tenon broaching force in the y direction is: , , ;

[0070] in is the cutting force of the top cutting edge, is the cutting force of the side cutting edge, It is the tooth rise of the broach tooth top, which is equivalent to the cutting depth of the tooth top. is the width of the broach teeth, is the area cutting force coefficient of the top cutting edge, is the cutting force coefficient of the top cutting edge length, It is the tooth lift of the broach tooth side, which is equivalent to the cutting depth of the tooth side. The length of the broach tooth side involved in cutting, is the area cutting force coefficient of the cutting edge on the tooth side, is the cutting force coefficient of the cutting edge length on the tooth side.

[0071] Turbine disc mortise and tenon broaching force in z direction: , , ;

[0072] in is the cutting force of the top cutting edge, is the cutting force of the side cutting edge, It is the tooth rise of the broach tooth top, which is equivalent to the cutting depth of the tooth top. is the width of the broach teeth, is the area cutting force coefficient of the top cutting edge, is the cutting force coefficient of the length of the top cutting edge, It is the tooth lift of the broach tooth side, which is equivalent to the cutting depth of the tooth side. The length of the broach tooth side involved in cutting, is the area cutting force coefficient of the cutting edge on the tooth side, is the cutting force coefficient of the length of the cutting edge on the tooth side.

[0073] S1-2. Establishing a multi-tooth broaching force model

[0074] The tool adopts a multi-tooth broach. Based on the single-tooth broaching force model in S1-1, a multi-tooth broaching force model is constructed to calculate the broaching force of the turbine disc tenon groove in the x, y, and z directions when the multi-tooth broach is cutting.

[0075] Select the commonly used turbine disc tenon and groove cutting parameters, set the tooth rise of the cutter tooth top, the width of the cutter tooth top, the tooth rise of the cutter tooth side, and the cutting width of the cutter tooth side respectively: ;

[0076] The broaching force of a single tooth of the broach in the x direction is: , , ;

[0077] is the cutting force of the top cutting edge of a single tooth of the broach in the x direction; is the cutting force of the side cutting edge of a single tooth of the broach in the x direction;

[0078] The broaching force of a single tooth in the y direction is: , , ;

[0079] is the cutting force of the top cutting edge of a single tooth of the broach in the y direction; is the cutting force of the side cutting edge of a single tooth of the broach in the y direction;

[0080] The broaching force of a single tooth in the z direction is: , , ;

[0081] is the cutting force of the top cutting edge of a single tooth of the broach in the z direction; It is the cutting force of the side cutting edge of a single tooth of the broach in the z direction.

[0082] Assume that when the mortise and tenon are broached stably, there are n teeth on the tool involved in cutting, n is a natural number, and the tool is generally provided with 3-4 teeth; then during stable broaching, the broaching forces in the x, y, and z directions are respectively: ; ; .

[0083] S2. Mechanical deformation analysis

[0084] Conduct mechanical deformation analysis on turbine disc mortise and tenon broaching machine, establish a three-dimensional coordinate system, construct a finite element model, and set boundary conditions (such as material properties); conduct static analysis under the action of cutting load under common mortise and tenon broaching process parameters;

[0085] S2-1, apply the cutting force load under the common mortise and tenon process parameters, refer to the cutting force calculated by the broaching force model in step S1, and the mortise and tenon broaching machine constraint conditions, and obtain the workpiece deformation in the x, y, and z directions, set as .

[0086] S2-2, constrain the workpiece deformation to the above three-dimensional coordinate system, use laser to measure the displacement change of the mortise and tenon cutting point in the x, y, and z directions, and set the displacement change to , obtained by comparing the positions of the cutting points before and after cutting, that is: ; ; ;

[0087] Among them: x1, x2 are the position coordinates of the cutting point in the x direction after and before cutting respectively; y1, y2 are the position coordinates of the cutting point in the y direction after and before cutting respectively; z1, z2 are the position coordinates of the cutting point in the z direction after and before cutting respectively.

[0088] S2-3, repeat the above process under another process parameter to obtain the second set of workpiece deformation and displacement change values, where the second set of calculated deformation is recorded as .

[0089] S2-4. Based on the values ​​of multiple sets of workpiece deformation and displacement changes, linear equation fitting is performed to obtain the corresponding linear equation: ; ; ;

[0090] in, They are the weights and biases in the corresponding linear directions, respectively, and can be obtained by the workpiece deformation in the x, y, and z directions calculated under multiple sets of different process parameters and the cutting point displacement deformation obtained by laser measurement.

[0091] S3, Positioning compensation

[0092] When using a five-axis CNC broaching machine to process different types of mortise and tenon grooves, the cutting force is first calculated based on the broaching force model constructed in S1. The calculated cutting force load is applied to the finite element model of the mortise and tenon broaching machine to obtain the workpiece deformation. Then, the displacement change of the corresponding cutting point is calculated based on the linear equation in S2. The displacement changes in the three directions are set as: ;

[0093] When machining the tenon groove of a turbine disc, if the initial positioning coordinates of the tenon groove are: ;

[0094] Then the accurate positioning coordinates after considering cutting deformation are: , , .

[0095] The above are only some embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have combinations and modifications of the aforementioned various technical features. Without departing from the spirit and scope of the present invention, those skilled in the art may improve, modify, or replace the present invention with equivalents, or apply the structure or method of the present invention to other fields to achieve the same effect, which all fall within the scope of protection included in the present invention.

Claims

1. A method for accurately positioning the tenon groove of a turbine disc for a five-axis CNC broaching machine, characterized in that: The following steps are involved: S1. Constructing the broaching force model S1-1, Single tooth broaching force model The broaching force test was carried out. The workpiece was made of the same material as the tenon workpiece, and the tool was a single-tooth broach. The angle and material of the tool were consistent with those of the broach for broaching the turbine disk tenon. Based on the test results, the turbine disk tenon broaching force coefficients in the x, y, and z directions were obtained to establish a single-tooth broaching force model. S1-2, Multi-tooth Broaching Force Model The tool adopts a multi-tooth broach. Based on the single-tooth broaching force model in S1-1, a multi-tooth broaching force model is constructed to calculate the broaching force of the turbine disc tenon groove in the x, y, and z directions when the multi-tooth broach is cutting. S2. Mechanical deformation analysis Conduct mechanical deformation analysis on turbine disc tenon-groove broaching machine, establish three-dimensional coordinate system, construct finite element model, and set boundary conditions; Static analysis is performed under the action of cutting load under common mortise and tenon broaching process parameters; including: S2-1, calculate the deformation of the workpiece based on the cutting force; S2-2, placing the workpiece deformation obtained in S2-1 into a three-dimensional coordinate system, and using a laser to measure the displacement change of the mortise and tenon cutting point; S2-3, repeating steps S2-1 and S2-2 to obtain multiple sets of values ​​of workpiece deformation and displacement variation; S2-4, performing linear equation fitting based on multiple sets of values ​​of workpiece deformation and displacement variation to obtain a corresponding linear equation; S3, Positioning compensation When a five-axis CNC broaching machine is used to process a mortise and tenon, the cutting force is first calculated based on the broaching force model constructed in S1. The calculated cutting force load is applied to the finite element model of the mortise and tenon broaching machine to obtain the workpiece deformation. Then, the displacement change of the cutting point is calculated based on the linear equation in S2. The displacement changes in the three directions are set as , , , when the turbine disc tenon groove is actually processed, if the initial positioning coordinates of the tenon groove are , , , then the accurate positioning coordinates after considering cutting deformation are: ； ； 。 2. The method for accurately positioning the tenon and groove of a turbine disc for a five-axis CNC broaching machine according to claim 1 is characterized in that: In step S1-1, the following operations are included: according to the cutting principle, the mortise and tenon broaching force is divided into the top cutting edge cutting force and the side cutting edge cutting force, and the turbine disc mortise and tenon broaching force in the x direction is: ， （1） in is the cutting force of the top cutting edge, is the cutting force of the side cutting edge; ， （2） in is the tooth lift of the broach tooth top; is the width of the broach tooth top, is the area cutting force coefficient of the top cutting edge, is the cutting force coefficient of the length of the top cutting edge; ， （3） in is the tooth lift on the broach tooth side, The length of the broach tooth side involved in cutting, is the area cutting force coefficient of the cutting edge on the tooth side, is the cutting force coefficient of the cutting edge length on the tooth side.

3. The method for accurately positioning the tenon and groove of a turbine disc for a five-axis CNC broaching machine according to claim 2, characterized in that: Step S1-1 includes the following operations: using a single-tooth broach to perform cutting tests with different tooth top widths, tooth lifts, and different tooth side lifts and widths, and calculating the cutting force coefficient in the x direction based on formulas (1)-(3).

4. The method for accurately positioning the tenon and groove of a turbine disc for a five-axis CNC broaching machine according to claim 3 is characterized in that: Step S1-1 includes the following operations: keep the tooth lift and cutting width of the broach tooth top unchanged, taking them as 0.08 mm and 2.5 mm respectively; set the tooth lift on the broach tooth side to 0.07, 0.08, 0.09, and 0.10 mm respectively; set the cutting width on the broach tooth side to 1, 1.5, 2, and 2.5 mm respectively; and calculate the relevant cutting force coefficient on the broach tooth side based on the test results.

5. The method for accurately positioning the tenon and groove of a turbine disc for a five-axis CNC broaching machine according to claim 4 is characterized in that: Step S1-1 includes the following operations: keep the tooth lift and cutting width on the broach tooth side unchanged, taking 0.08 mm and 2 mm respectively, setting the tooth lift of the broach tooth top to 0.07, 0.08, 0.09, and 0.10 mm respectively, and the cutting width of the broach tooth top to 1, 1.5, 2, and 2.5 mm respectively, and calculate the relevant cutting force coefficient of the broach tooth top based on the test results.

6. The method for accurately positioning the tenon groove of a turbine disc for a five-axis CNC broaching machine according to claim 5, characterized in that: In step S1-1, the method of calculating the cutting force coefficient in the x direction is adopted, and the cutting force coefficients in the y and z directions are calculated similarly, and a single-tooth broaching force model in the y and z directions is constructed.

7. The method for accurately positioning the tenon and groove of a turbine disc for a five-axis CNC broaching machine according to claim 1, characterized in that: In step S1-2, the tooth lift of the top of the cutter tooth, the width of the top of the cutter tooth, the tooth lift of the side of the cutter tooth, and the cutting width of the side of the cutter tooth are respectively: ; Then the broaching force of a single tooth of the broach in the x direction is: ， ， ； is the cutting force of the top cutting edge of a single tooth of the broach in the x direction; is the cutting force of the side cutting edge of a single tooth of the broach in the x direction; is the area cutting force coefficient of the top cutting edge in the x direction; is the length of the top cutting edge in the x direction, cutting force coefficient; is the area cutting force coefficient of the cutting edge on the tooth side in the x direction; is the cutting force coefficient of the length of the cutting edge on the tooth side in the x direction; The broaching force of a single tooth in the y direction is: ， ， ， is the cutting force of the top cutting edge of a single tooth of the broach in the y direction; is the cutting force of the side cutting edge of a single tooth of the broach in the y direction; is the area cutting force coefficient of the top cutting edge in the y direction; is the length of the top cutting edge in the y direction, cutting force coefficient; is the area cutting force coefficient of the cutting edge on the tooth side in the y direction; is the cutting force coefficient of the length of the cutting edge on the tooth side in the y direction; The broaching force of a single tooth in the z direction is: ， ， ， is the cutting force of the top cutting edge of a single tooth of the broach in the z direction; is the cutting force of the side cutting edge of a single tooth of the broach in the z direction; is the area cutting force coefficient of the top cutting edge in the z direction; is the length of the top cutting edge in the z direction, cutting force coefficient; is the area cutting force coefficient of the cutting edge on the tooth side in the z direction; is the cutting force coefficient of the length of the cutting edge on the tooth side in the z direction; Assume that when the mortise and tenon are broached stably, there are n teeth on the tool involved in cutting. Then, during stable broaching, the broaching forces in the x, y, and z directions are: ； ； 。 8. The method for accurately positioning the tenon and groove of a turbine disc for a five-axis CNC broaching machine according to claim 1, characterized in that: In step S2-1, the following operations are included: the cutting force is calculated using the broaching force model in step S1, and the deformation of the workpiece in the x, y, and z directions is obtained, which are respectively set as , , .

9. The method for accurately positioning the tenon and groove of a turbine disc for a five-axis CNC broaching machine according to claim 8, characterized in that: In step S2-2, the following operations are included: using laser to measure the displacement change of the cutting point in the x, y, and z directions, which are respectively set as: , , , the displacement change is obtained by comparing the positions of the cutting points before and after cutting, that is: ， ， ， Among them: x1, x2 are the position coordinates of the cutting point in the x direction after and before cutting respectively; y1, y2 are the position coordinates of the cutting point in the y direction after and before cutting respectively; z1 and z2 are the position coordinates of the cutting point in the z direction after and before cutting respectively.

10. The method for accurately positioning the tenon and groove of a turbine disc for a five-axis CNC broaching machine according to claim 1, characterized in that: In step S2, different process parameters are used to conduct experiments to obtain at least two different sets of workpiece deformation and displacement variation values.

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