Efficient process parameter optimization method for mortise of turbine disc of numerical control broaching machine

Abstract

The invention belongs to the technical field of machining, and particularly relates to a numerical control broaching machine turbine disc mortise efficient process parameter optimization method which comprises the following steps: S1, mortise surface performance parameter testing; s2, mortise cutting force modeling is carried out, and a broaching force test is carried out to obtain related cutting force coefficients of mortise cutting; s3, performing mortice broaching machine modal analysis and stable region solving; s4, efficient machining parameters of the mortises are determined; according to the numerical control broaching machine turbine disc mortise efficient process parameter optimization method, the numerical control broaching machine turbine disc mortise efficient process parameter optimization method is provided on the basis of the cutting principle, mechanical vibration, deep learning and other theories, the optimized machining process parameter interval can be obtained after influences of various factors in the actual mortise cutting process are fully considered, and therefore the machining efficiency and precision of a mortise broaching machine are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing broaching machines for turbine disk tenon grooves, and particularly relates to a method for optimizing high-efficiency process parameters of a numerically controlled broaching machine for turbine disk tenon grooves. Background Art

[0002] The turbine disk is one of the key components in aeroengines and gas turbines; the tenon groove is the notch on the turbine disk for installing blades, and the shape and dimensional accuracy of the tenon groove are directly related to the installation accuracy, operation stability, and overall performance of the blades. With the continuous improvement of the performance requirements of gas turbines and engines, the machining accuracy requirements for turbine disk tenon grooves are increasing day by day, posing extremely stringent challenges to machining efficiency. Turbine disk tenon grooves are generally formed by cutting, and the process parameters used during cutting are the key factors determining the machining efficiency of the tenon groove. Moreover, the cutting process parameters are comprehensively affected by machining conditions such as tools, workpieces, and machine tools, as well as target performance parameters such as machining dimensional accuracy and surface roughness. If the cutting process parameters are not reasonably selected, it will not only lead to low machining efficiency but also inevitably cause chatter, significantly reducing the tool service life and workpiece machining quality. In view of this, this application aims to propose a method for optimizing high-efficiency process parameters of a numerically controlled broaching machine for turbine disk tenon grooves, which can significantly improve the machining efficiency and accuracy of the tenon groove broaching machine. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a method for optimizing high-efficiency process parameters of a numerically controlled broaching machine for turbine disk tenon grooves.

[0004] The technical solution of the present invention is: a method for optimizing high-efficiency process parameters of a numerically controlled broaching machine for turbine disk tenon grooves; including the following steps: S1. Experiment on surface performance parameters of the tenon groove Conduct tenon groove broaching experiments, measure the data of surface roughness, surface hardness, residual stress, and cutting deformation of the tenon groove under different process parameters, and analyze the relationships between the surface roughness, surface hardness, residual stress, and cutting deformation of the tenon groove and the process parameters.

[0005] S2. Modeling of cutting force for the tenon groove Establish a cutting force model during tenon groove cutting; and conduct broaching force experiments to obtain the cutting force coefficient during the tenon groove cutting process.

[0006] S3. Modal analysis of the tenon groove broaching machine and solution of the stable region S3-1. Measure and obtain the modal parameters of each point (node) of the workpiece and the tool The modal parameters include modal stiffness, modal damping, modal mass, and modal transfer function; through the impact hammer test, first obtain the modal transfer function of the workpiece , and the modal transfer function of the tool tip ; Subsequently, according to the cutting path, a series of points are evenly arranged on each tool in sequence, and are marked in sequence as: (where i is a natural number), and through modal tests, the modal transfer functions of each node of the tool are obtained in sequence .

[0007] S3-2. Establish the dynamic equation Considering the influence of the broaching speed on damping and stiffness, the established cutting dynamics equation is as follows: (5) Where: is the mass matrix of the cutting system, and M is a constant 0 , a finite element model can be established for components such as motors and bearings in the cutting system, and its mass matrix can be quickly obtained in the finite element software; is the stiffness matrix; is the broaching speed, G represents the comprehensive influence coefficient of the node speed and the broaching speed on damping, D is the equivalent viscous damping matrix, which is determined by the properties of the material, q is the node displacement, is the node speed, is the node acceleration, F(t) is the node force vector; Then the processing dynamics equation between the tool and the workpiece is: ; ; Where: is the mass matrix of the workpiece, is the mass matrix of the tool, is the damping matrix of the workpiece, is the stiffness matrix of the workpiece, are the displacements of the workpiece and the tool tip respectively, , are the speeds of the workpiece and the tool tip respectively, are the accelerations of the workpiece and the tool tip respectively, is the force vector of the workpiece, is the force vector of the tool tip.

[0008] S3-3. Cutting Depth Analysis The cutting depth calculation formula is as follows: ; ; ; Where: is the cutting cycle, is the dynamic cutting depth, is the cutting width, is the cutting force coefficient; it can be obtained by fitting according to the experimental data from orthogonal cutting tests at different cutting depths; Taking the Laplace transform of the cutting depth h, we get: ; The cutting dynamics equation is transformed into: ; ; Where: represents the cutting depth of the previous tooth of the tool, represents the cutting depth of the current tooth of the tool, represents the cutting depth generated by the workpiece offset caused by the current workpiece vibration, represents the cutting depth generated by the workpiece offset caused by the workpiece vibration in the previous cycle, represents: the Laplace factor, represents: the natural frequency of the broaching system, represents the excitation frequency of broaching, which is determined by the broaching speed and the pitch of the broach teeth, and is the ratio of the broaching speed to the pitch of the broach teeth; N represents the influence coefficient of the broaching speed on damping.

[0009] S3-4. Solution of the Stable Region 1) During the cutting process, under the action of the cutting force, the transfer function between different nodes of the tool and the workpiece is: ; Taking After Laplace transform, the obtained The relationship is as follows: ; The method for solving the stable region in the frequency domain is used to obtain the stable region in the cutting process of different nodes of the workpiece: ; 2) The cutting transfer function of different nodes of the workpiece is established through the modal transfer function of the workpiece and the modal transfer function of each node of the tool , and The transfer function in Laplace form is obtained through Laplace transform ; 3) According to and by the method of solving the stable region in the frequency domain, the stable region in the cutting process of different nodes of the tool is obtained; S4. Determine the high-efficiency machining parameters for the mortise groove S4-1. Calculate the stable regions of all the cutter teeth at the nodes on the broach according to the method in S3-4; and find the intersection of the stable regions of the cutter teeth at different nodes on the broach to obtain the stable region considering the dynamic characteristics of all the cutter teeth on the tool; S4-2. Based on the broaching speed range of the broaching machine, obtain the maximum theoretical tooth depth to avoid chatter at different broaching speeds, and obtain the process parameter range A considering chatter; S4-3. With the parameter technical standards of the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise groove as constraints, obtain the machining parameter range B; S4-4. Intersect the process parameter range A and the machining parameter range B to obtain the effective process parameter range.

[0010] Furthermore, in step S1, the relationships between the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise groove and the machining parameters are established as follows: ; ; ; ; where is the surface roughness of the mortise groove workpiece; is the surface hardness of the workpiece; is the surface residual stress of the workpiece; is the cutting deformation; , , , are the influence indices between the surface roughness, surface hardness, surface residual stress, cutting deformation of the machined workpiece and the machining parameters respectively; is the broaching speed, is the tooth increment of the broach.

[0011] Furthermore, in step S1, the constraint conditions for the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise groove are as follows: ; ; ; ; Determine the maximum broaching speed and the tooth increment of the broach according to the following formula (6): ; (6) is the maximum material removal efficiency of the mortise groove broaching under the above constraint conditions.

[0012] Furthermore, the surface roughness range of the mortise groove is 1.6 - 3.2 microns; the surface hardness range is 30 - 40 HRc, the surface residual stress range is 400 - 800 Mpa, and the cutting deformation range is -0.12 - 0.12 microns.

[0013] Furthermore, during the broaching test, the tooth increment is 0.06 - 0.12 mm, and the broaching speed is 6 - 10 m / min.

[0014] Furthermore, step S2 includes: S2-1. Establish a cutting force model for single-tooth broaching The workpiece uses the same material as the mortise groove workpiece, and the tool is a single-tooth broach. Its tool angles and materials are the same as those of the broach for broaching the turbine disk mortise groove; according to the cutting principle, the mortise groove broaching force is divided into the cutting force of the top cutting edge and the cutting force of the side cutting edge; let the broaching force of the turbine disk mortise groove in the x direction be: , (1) where is the cutting force of the top cutting edge, is the cutting force of the side cutting edge; , (2) where: h 1 is the tooth increment at the top of the broach tooth, which is equivalent to the cutting depth at the top of the tooth, is the width of the broach tooth, is the area cutting force coefficient of the top cutting edge, is the length cutting force coefficient of the top cutting edge; , (3) where: h 2 is the tooth rise amount on the side of the broach tooth, equivalent to the cutting depth on the side of the broach tooth, is the length of the broach tooth side participating in cutting, is the area cutting force coefficient of the cutting edge on the side of the broach tooth, is the length cutting force coefficient of the cutting edge on the side of the broach tooth; Conduct multiple groups of broaching experiments to obtain each cutting force coefficient in formulas (1)-(3), and establish a broaching force model when a single tooth participates in cutting in the x direction of the mortise groove.

[0015] Furthermore, step S2 includes: S2-2. Obtain the total cutting force coefficient According to the single-tooth cutting force model in S2-1, let the tooth rise amount of the broach tooth tip, the tooth tip width of the broach tooth, the tooth rise amount of the broach tooth side, and the cutting width of the broach tooth side be ; Then the broaching force of a single tooth in the x direction is: , , ; where: is the cutting force of the top cutting edge of a single broach tooth in the x direction; is the cutting force of the side cutting edge of a single broach tooth in the x direction; Transform the broaching force of a single tooth into the following model: ; (4) where: h is the tooth rise amount, is the cutting width of the broach tooth, is the total cutting force coefficient; According to the above formula, calculate the total cutting force coefficient .

[0016] Furthermore, in step S2-1, first, keep the tooth rise amount and cutting width of the broach tooth tip unchanged, let the tooth rise amount of the broach tooth side and the cutting width of the broach side change, conduct multiple groups of experiments, and calculate the relevant cutting force coefficients of the broach tooth side; then, keep the tooth rise amount and cutting width of the broach side unchanged, let the tooth rise amount of the broach tooth tip and the cutting width of the broach tooth tip change, conduct multiple groups of experiments, and calculate the relevant cutting force coefficients of the broach tooth tip; finally, obtain all the cutting force coefficients in the x direction.

[0017] Furthermore, considering the actual cutting process and the supporting parameter set of the mortise and tenon groove, the tooth rise amount between the top and the side of the broach tooth is between 0.070 and 0.100 mm, the cutting width at the tooth top is between 1 and 2.8 mm, and the width at the side of the broach is between 1 - 3 mm; First, the tooth rise amount and the cutting width at the tooth top of the broach are taken as 0.08 mm and 2.5 mm respectively, the tooth rise amounts at the side of the broach tooth are 0.07, 0.08, 0.09, 0.1 mm, and the cutting widths at the side of the broach are 1, 1.5, 2, 2.5 mm respectively. Experiments are carried out to obtain the cutting force coefficients at the side of the broach tooth. Among them, each cutting force coefficient has multiple values, and the average value of the multiple values of the cutting force coefficient is taken; Then, the tooth rise amount and the cutting width at the side of the broach are taken as 0.08 mm and 2 mm respectively, the tooth rise amounts at the tooth top of the broach are 0.07, 0.08, 0.09, 0.1 mm, and the cutting widths at the tooth top of the broach are 1, 1.5, 2, 2.5 mm respectively, to obtain the cutting force coefficients at the tooth top of the broach; During the calculation process, each cutting force coefficient has multiple values, and the average value of the multiple values of the relevant cutting force coefficient is taken; Finally, the cutting force coefficient in the x - direction is obtained.

[0018] Furthermore, in step S4 - 2, considering the actual deviation, the actual maximum tooth rise amount is set to 0.6 times the maximum theoretical tooth rise amount.

[0019] The beneficial effects of the present invention compared with the prior art: Based on theories such as cutting principle, mechanical vibration, and deep learning, the present invention proposes an efficient process parameter optimization method for the mortise and tenon groove of the turbine disk of a numerical control broaching machine. After fully considering the influence of various factors in the actual cutting process of the mortise and tenon groove, the optimized processing parameter range can be obtained, thereby significantly improving the processing efficiency and accuracy of the mortise and tenon broaching machine. Specific Embodiments

[0020] To make the purpose, technical solutions, and advantages of the present invention clearer, in the following description, the descriptions of well - known structures and technologies are omitted to avoid unnecessarily confusing the concepts in the present invention.

[0021] Embodiment 1

[0022] This embodiment is an efficient process parameter optimization method for the mortise and tenon groove of the turbine disk of a numerical control broaching machine; it includes the following steps: S1. Mortise and Tenon Groove Surface Performance Parameter Test Carry out mortise and tenon groove broaching tests, measure the data of the surface roughness, surface hardness, residual stress, and cutting deformation amount of the mortise and tenon groove under different process parameters (tooth rise amount, broaching speed), and analyze the relationship between the surface roughness, surface hardness, residual stress, and cutting deformation amount of the mortise and tenon groove and the process parameters; Among them, the tooth increment is designed to be 0.06 - 0.12 mm, and the broaching speed is designed to be 6 - 10 m / min; the technical standards for the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise groove are as follows: the surface roughness range of the mortise groove is 1.6 - 3.2 μm; the surface hardness range is 30 - 40 HRc, the surface residual stress range is 400 - 800 Mpa, and the cutting deformation range is -0.12 - 0.12 μm.

[0023] The relationships between the surface roughness, surface hardness, residual stress, and cutting deformation of the established mortise groove and the processing parameters are as follows: ; ; ; ; Among them: is the surface roughness of the mortise groove workpiece; is the surface hardness of the workpiece; is the surface residual stress of the workpiece; is the cutting deformation; is the broaching speed, is the tooth increment of the broach; 、 、 、 are the influence indices between the surface roughness, surface hardness, surface residual stress, cutting deformation of the machined workpiece and the processing parameters respectively.

[0024] The constraints on the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise groove are as follows: ; The surface roughness range of the mortise groove is 1.6 - 3.2 μm; that is, and are 1.6 and 3.2 respectively; ; The surface hardness of the mortise groove is 30 - 40 HRc; that is, and are 30 and 40 respectively; ; The surface residual of the mortise groove is 400 - 800 Mpa; that is, and They are 400 and 800 respectively; ; The dimensional deformation range is -0.12 to +0.12 microns; Then the maximum broaching speed and the tooth feed of the broach can be determined according to the following formula (6): ; (6) Where is the maximum material removal efficiency of the mortise broaching under the above constraints.

[0025] S2. Modeling of Mortise Cutting Force Establish a cutting force model for mortise cutting; and conduct a broaching force test to obtain the cutting force coefficient during mortise cutting; S2-1. Establishment of Cutting Force Model for Single-Tooth Broaching The workpiece uses the same material as the mortise workpiece, and the tool is a single-tooth broach. Its tool angles and materials are the same as those of the broach for broaching the turbine disk mortise; according to the cutting principle, the mortise broaching force is divided into the cutting force of the top cutting edge and the cutting force of the side cutting edge; let the broaching force of the turbine disk mortise in the x direction be: , (1) Where is the cutting force of the top cutting edge, is the cutting force of the side cutting edge; , (2) Where: h 1 is the tooth feed at the top of the broach tooth, which is equivalent to the cutting depth at the top of the tooth, is the width of the broach tooth, is the area cutting force coefficient of the top cutting edge, is the length cutting force coefficient of the top cutting edge; , (3) Where: h 2 is the tooth feed on the side of the broach tooth, which is equivalent to the cutting depth on the side of the tooth, is the length of the side of the broach tooth participating in cutting, is the area cutting force coefficient of the side cutting edge of the tooth, is the length cutting force coefficient of the side cutting edge of the tooth.

[0026] Using a single-edge broach, a side-pulling cutting force test is conducted. With one broach, cutting tests with different top widths, tooth increments, and side tooth increments and widths of the broach teeth can be achieved. By adjusting the vertical height and horizontal distance of the broach teeth, the cutting depth and width of the broach can be adjusted, and the tooth increments, widths of the broach tip, and tooth increments and widths of the broach teeth can be obtained. By conducting multiple broaching experiments, the cutting force coefficients in formulas (1)-(3) can be obtained, and a broaching force model for single-tooth cutting in the x direction of the mortise groove can be established.

[0027] Specifically, considering the actual cutting process and supporting parameter sets of the mortise groove, the tooth increments of the broach tip and broach teeth are 0.070 - 0.100 mm, the cutting width (cutting edge length) of the broach tip is 1 - 2.8 mm, and the width (cutting edge length) of the broach side is 1 - 3 mm. First, with the tooth increment and cutting width of the broach tip unchanged, taking 0.08 mm and 2.5 mm respectively, and the tooth increments of the broach teeth being 0.07, 0.08, 0.09, 0.1 mm, and the cutting widths (cutting edge lengths) of the broach side being 1, 1.5, 2, 2.5 mm respectively, the cutting force coefficients of the broach side are obtained. Each cutting force coefficient has multiple values, and the average value of the multiple values of the cutting force coefficient is taken. Second, with the tooth increment and cutting width of the broach side unchanged, taking 0.08 mm and 2 mm respectively, and the tooth increments of the broach tip being 0.07, 0.08, 0.09, 0.1 mm, and the cutting widths (cutting edge lengths) of the broach tip being 1, 1.5, 2, 2.5 mm respectively, the cutting force coefficients of the broach tip are obtained. Each cutting force coefficient has multiple values, and the average value of the multiple values of the cutting force coefficient is taken; thus, the cutting force coefficients in the x direction can be obtained; similarly, the cutting force coefficients in other directions (y, z) can be obtained.

[0028] S2-2. Obtain the total cutting force coefficient According to the single-tooth cutting force model in S2-1, let the tooth lift of the broach tooth, the width of the broach tooth tip, the tooth lift of the broach tooth side, and the cutting width of the broach tooth side be ; Then the broaching force of a single tooth in the x direction is , , ; Among them: 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; Transform the broaching force of a single tooth into the following model ; (4) Where: h is the tooth feed, is the cutting width of the tooth edge, is the total cutting force coefficient; the total cutting force coefficient can be calculated according to formula (4) .

[0029] S3. Modal Analysis and Stable Region Solution of the Mortise Broaching Machine S3-1. Measure the modal parameters of each point (node) of the workpiece and the tool The modal parameters include modal stiffness, modal damping, modal mass and modal transfer function; through the impact hammer test, the modal transfer function of the workpiece is obtained first , the modal transfer function of the tool tip ; then, according to the cutting path, a series of points are evenly arranged on each tool in turn, and are marked in turn as: (i is a natural number), and the modal transfer functions of each node of the tool are obtained in turn through the modal test .

[0030] S3-2. Establish the dynamic equation Considering the influence of the broaching speed on damping and stiffness, the dynamic equation of cutting is established as follows: (5) Where: is the mass matrix of the cutting system, and M is a constant 0 , a finite element model of components such as motors and bearings in the cutting system can be established, and its mass matrix can be quickly obtained in the finite element software; is the stiffness matrix, is the broaching speed, G represents the comprehensive influence coefficient of the node speed and the broaching speed on damping, D is the equivalent viscous damping matrix, which is determined by the properties of the material, q is the node displacement, is the node speed, is the node acceleration, F(t) is the node force vector; Then the processing dynamic equation between the tool and the workpiece is: ; ; Where: is the mass matrix of the workpiece, is the mass matrix of the cutting tool, is the damping matrix of the workpiece, is the stiffness matrix of the workpiece; are the displacements of the workpiece and the tool tip respectively, , are the velocities of the workpiece and the tool tip respectively, are the accelerations of the workpiece and the tool tip respectively; is the force vector of the workpiece, is the force vector of the tool tip.

[0031] S3-3. Analysis of cutting depth The formula for calculating the cutting depth is as follows: ; ; ; Where: is the cutting cycle, is the dynamic cutting depth, is the cutting width, is the cutting force coefficient; obtained by fitting according to the experimental data from orthogonal cutting tests at different cutting depths.

[0032] Taking the Laplace transform of the cutting depth h, we get: ; The cutting dynamics equation is transformed into: ; ; Where: represents the cutting depth of the previous tooth of the cutting tool, represents the cutting depth of the current tooth of the cutting tool, represents the cutting depth generated by the workpiece offset caused by the current workpiece vibration, represents the cutting depth generated by the workpiece offset caused by the workpiece vibration in the previous cycle; represents: the Laplace factor, Denote: the natural frequency of the broaching system Denote the excitation frequency of broaching, which is determined by the broaching speed and the pitch of broach teeth, and is the ratio of the broaching speed to the pitch of broach teeth; N denotes the influence coefficient of broaching speed on damping.

[0033] S3-4, Solving the stability region 1) During the cutting process, under the action of the cutting force, the transfer function between different nodes of the tool and the workpiece is: ; Substitute After Laplace transform, the obtained The relationship is as follows: ; According to the method of solving the stability region in the frequency domain, obtain the stability region in the cutting process of different nodes of the workpiece: ; 2) Through the modal transfer function of the workpiece and the modal transfer function of each node of the tool, establish the cutting processing transfer function of different nodes of the workpiece , Substitute After Laplace transform, obtain the transfer function in Laplace form ; 3) According to And through the method of solving the stability region in the frequency domain, obtain the stability region in the cutting process of different nodes of the tool; S4. Determine the high-efficiency machining parameters of the mortise groove S4-1. Calculate the stability regions of all node teeth on the broach according to the method in S3-4; and find the intersection of the stability regions of different node teeth on the broach to obtain the stability region considering the dynamic characteristics of all teeth on the tool; S4-2. Based on the broaching speed range of the broaching machine, obtain the maximum theoretical tooth depth to avoid chatter at different broaching speeds. Considering the actual deviation, set the actual maximum tooth depth to 0.6 times the maximum theoretical tooth depth; obtain the optimal process parameter range A considering chatter; S4-3. With the parameter technical standards of the surface roughness, surface hardness, residual stress, and cutting deformation amount of the mortise groove as constraints, obtain the machining parameter range B; S4-4. Find the intersection of the process parameter range A and the machining parameter range B to obtain the effective process parameter range.

[0034] 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 can have combinations and variations of the foregoing various technical features. Without departing from the spirit and scope of the present invention, improvements, variations, equivalent replacements made by those skilled in the art, or the application of the structure or method of the present invention to other fields to achieve the same effect all fall within the protection scope of the present invention.

Claims

1. A method for optimizing efficient process parameters of turbine disc tenon and groove of CNC broaching machine, characterized in that: The following steps are involved: S1. Mortise and tenon surface performance parameter test Carry out mortise and tenon broaching tests, measure the surface roughness, surface hardness, residual stress and cutting deformation data of the mortise and tenon under different process parameters, and establish the relationship between the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon and the process parameters; S2. Mortise and tenon cutting force modeling The cutting force model of mortise and tenon cutting is established; and the broaching force test is carried out to obtain the cutting force coefficient of mortise and tenon cutting; S3. Modal analysis and stable region solution of tongue and groove broaching machine S3-1. Measure and obtain the modal parameters of the workpiece and tool nodes Modal parameters include modal stiffness, modal damping, modal mass and modal transfer function. Through the hammer test, the modal transfer function of the workpiece is first obtained. , tool tip modal transfer function ; Then, according to the cutting path, a series of points are evenly spaced and arranged on each tool, marked as: Through modal tests, the modal transfer functions of each node of the tool are obtained in turn. ; S3-2. Establishing the kinetic equation Considering the influence of broaching speed on damping and stiffness, the established cutting dynamics equation is as follows: （5） in: is the mass matrix of the cutting system, is a constant M0, is the stiffness matrix, is the broaching speed, G represents the comprehensive influence coefficient of node speed and broaching speed on damping, D is the equivalent viscous damping matrix, which is determined by the properties of the material. q is the node displacement, is the node speed, is the node acceleration, F(t) is the nodal force vector; Then the machining dynamics equation between the tool and the workpiece is: ， ， in: is the mass matrix of the workpiece, is the mass matrix of the tool, is the damping matrix of the workpiece, is the stiffness matrix of the workpiece, are the displacements of the workpiece and tool tip, , are the speeds of the workpiece and tool tip, are the accelerations of the workpiece and tool tip, respectively. is the force vector of the workpiece, is the force vector of the tool tip; S3-3. Cutting Depth Analysis The calculation formula for the cutting depth is as follows: ， ， ， in: is the cutting cycle, is the dynamic cutting depth, is the cutting width, is the cutting force coefficient; Perform Laplace transform on the cutting depth h and we get: ； The cutting dynamics equation is converted to: ； ； Indicates the cutting depth of the previous tooth of the tool. Indicates the cutting depth of the current tooth of the tool. Indicates the cutting depth caused by the workpiece offset caused by the current workpiece vibration. Indicates the cutting depth caused by the workpiece deviation caused by the workpiece vibration in the previous cycle. Denotes: Laplace factor, Indicates: the natural frequency of the broaching system, It represents the excitation frequency of the broaching process, which is determined by the broaching speed and the spacing of the broach teeth, and is the ratio of the broaching speed to the spacing of the broach teeth; N represents the influence coefficient of broaching speed on damping; S3-4. Stable region solution During the cutting process, under the action of cutting force, the transfer function between different nodes of the tool and the workpiece is: ； Will After Laplace transformation, we get The relationship is as follows: ； According to the method of solving the stable region in the frequency domain, the stable region in the cutting process at different nodes of the workpiece is obtained: ； Through the modal transfer function of the workpiece and the modal transfer function of each node of the tool, the cutting transfer function of different nodes of the workpiece is established. ,Will After Laplace transformation, the transfer function in Laplace form is obtained ; in accordance with And by solving the stable region in the frequency domain, the stable region in the cutting process at different nodes of the tool is obtained; S4. Determine the efficient processing parameters of the mortise and tenon S4-1, finding the intersection of the stable regions of the teeth at different nodes on the broach, and obtaining the stable regions of the dynamic characteristics of all teeth on the broach; S4-2, based on the broaching speed range of the broaching machine, the maximum theoretical tooth lift to avoid chatter at different broaching speeds is obtained, and the process parameter range A when considering chatter is obtained; S4-3, taking the parameter technical standards of the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon as constraints, obtain the processing parameter range B; S4-4, finding the intersection of the process parameter interval A and the processing parameter interval B, thereby obtaining an optimized process parameter interval.

2. The method for optimizing efficient process parameters of turbine disc tenon and groove of CNC broaching machine according to claim 1 is characterized in that: In step S1, the established relationship between the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon and the processing parameters is as follows: ； ； ； ； in: is the surface roughness of the mortise and tenon workpiece, is the surface hardness of the workpiece, is the residual stress on the workpiece surface, is the cutting deformation, , , , They are the influence indexes of the surface roughness, surface hardness, surface residual stress, cutting deformation and processing parameters of the workpiece after processing. is the broaching speed, It is the amount of broach tooth lift.

3. The method for optimizing efficient process parameters of turbine disc tenon and groove of CNC broaching machine according to claim 2 is characterized in that: In step S1, the constraints of the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon are as follows: ； ； ； ； The maximum broaching speed is determined according to the following formula (6): And broach tooth lift : ； (6) It is the maximum material removal efficiency of the mortise and tenon broaching process under the above constraints.

4. The method for optimizing efficient process parameters of turbine disc tenon and groove of CNC broaching machine according to claim 3 is characterized in that: The surface roughness range of the mortise and tenon is 1.6-3.2 microns; the surface hardness range is 30-40HRc, the surface residual stress range is 400-800Mpa, and the cutting deformation range is -0.12 - 0.12 microns.

5. The method for optimizing efficient process parameters of turbine disc tenon and groove of CNC broaching machine according to claim 3 is characterized in that: During the broaching test, the tooth lift was 0.06-0.12 mm and the broaching speed was 6-10 m / min.

6. The method for optimizing efficient process parameters of turbine disc tenon and groove of CNC broaching machine according to claim 1 is characterized in that: Step S2 includes: S2-1, establishing a cutting force model for single-tooth broaching The workpiece is made of the same material as the mortise and tenon workpiece, and the tool is a single-tooth broach. Its tool angle and material are consistent with those of the broach used to broach the turbine disc mortise and tenon. 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. The turbine disc mortise and tenon broaching force in the x direction is: ， （1） in is the cutting force on the top cutting edge, is the cutting force of the side cutting edge; ，（2） Where h1 is the tooth lift 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; ，（3） Where h2 is the tooth lift on the broach tooth side, which is equivalent to the cutting depth on 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; multiple groups of broaching experiments were carried out to obtain the cutting force coefficients in formulas (1)-(3), and the broaching force model when a single tooth in the x direction of the mortise and tenon groove participates in cutting was established.

7. The method for optimizing efficient process parameters of turbine disc tenon groove of CNC broaching machine according to claim 6 is characterized in that: Step S2 includes: S2-2, obtaining the total cutting force coefficient According to the cutting force model in S2-1, the tooth top lift, tooth top width, tooth side lift, and tooth side cutting width are assumed to be ; Then the broaching force of a single tooth in the x direction is: ， ， ； in: 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; The broaching force of a single tooth Transform to the following model: ；（4） Where h is the tooth lift, is the cutting width of the blade teeth, is the cutting force coefficient; according to the above formula, the cutting force coefficient is calculated .

8. The method for optimizing efficient process parameters of turbine disc tenon and groove of CNC broaching machine according to claim 1 is characterized in that: In step S2-1, first, the tooth lift and cutting width of the broaching tool tooth top are kept unchanged, and the tooth lift and cutting width of the broaching tool tooth side are changed, and multiple groups of experiments are performed to calculate the relevant cutting force coefficients of the broaching tool tooth side; then, the tooth lift and cutting width of the broaching tool tooth side are kept unchanged, and the tooth lift and cutting width of the broaching tool tooth top are changed, and multiple groups of experiments are performed to calculate the relevant cutting force coefficients of the broaching tool tooth top; finally, all the cutting force coefficients in the x direction are obtained.

9. The method for optimizing efficient process parameters of turbine disc tenon and groove of CNC broaching machine according to claim 8, characterized in that: Taking into account the actual cutting process of the mortise and tenon and the matching parameter group, the tooth lift of the broaching tool tooth top and the tooth side is between 0.070 and 0.100 mm, the tooth top cutting width is between 1 and 2.8 mm, and the width of the broaching tool side is between 1 and 3 mm; first, the tooth lift of the broaching tool tooth top and the cutting width are set to 0.08 mm and 2.5 mm respectively, the tooth lift of the broaching tool tooth side is 0.07, 0.08, 0.09, and 0.1 mm, and the cutting width of the broaching tool side is 1, 1.5, 2, 2.5 mm, and experiments were carried out to obtain the cutting force coefficient of the broach tooth side; then, the tooth lift and cutting width on the broach side were set to 0.08 mm and 2 mm respectively, the tooth lift of the broach tooth top was 0.07, 0.08, 0.09, and 0.1 mm, and the cutting width of the broach tooth top was 1, 1.5, 2, and 2.5 mm respectively, to obtain the cutting force coefficient of the broach tooth top; each cutting force coefficient has multiple values, and the average of the multiple values ​​of the cutting force coefficient is taken; and then the cutting force coefficient in the x direction is obtained.

10. The method for optimizing efficient process parameters of turbine disc tenon groove of CNC broaching machine according to claim 1, characterized in that: In step S4-2, taking into account the actual deviation, the actual maximum tooth lift is set to 0.6 times the maximum theoretical tooth lift.

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