A high-efficiency process parameter optimization method for turbine disc mortise and tenon groove of CNC broaching machine

Abstract

The present invention belongs to the field of machining technology, and specifically relates to a method for optimizing the efficient process parameters of the tenon and groove of a turbine disk of a CNC broaching machine, comprising the following steps: S1, tenon and groove surface performance parameter test; S2, tenon and groove cutting force modeling, and broaching force test to obtain relevant cutting force coefficients of tenon and groove cutting; S3, tenon and groove broaching machine modal analysis and stable region solution; S4, determining the efficient processing parameters of the tenon and groove; the present invention proposes a method for optimizing the efficient process parameters of the tenon and groove of a turbine disk of a CNC broaching machine based on cutting principles, mechanical vibration, deep learning and other theories. After fully considering the influence of various factors in the actual cutting process of the tenon and groove, the optimized processing parameter range can be obtained, thereby significantly improving the processing efficiency and precision of the tenon and groove broaching machine.

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 method for optimizing efficient process parameters of a turbine disc tenon and groove of a numerically controlled broaching machine. Background Art

[0002] The turbine disc is one of the key components in aircraft engines and gas turbines; the mortise and tenon is the groove on the turbine disc used to install the blades. The shape and dimensional accuracy of the mortise and tenon are directly related to the installation accuracy, operating stability and overall performance of the blades. With the continuous improvement of gas turbine and engine performance requirements, the machining accuracy requirements of the turbine disc mortise and tenon are also increasing, which also poses an extremely stringent challenge to machining efficiency. The turbine disc mortise and tenon are generally formed by cutting, and the process parameters used during cutting are the key factors determining the machining efficiency of the mortise and tenon. The cutting process parameters are, in turn, affected by the combined influence of machining conditions such as the tool, workpiece, and machine tool, as well as target performance parameters such as machining dimensional accuracy and surface roughness. If the cutting process parameters are not selected properly, it will not only lead to low machining efficiency, but will also inevitably cause vibration, significantly reducing the tool life and workpiece machining quality. In view of this, the present application aims to propose an efficient process parameter optimization method for the mortise and tenon of a CNC broaching machine turbine disc, which can significantly improve the machining efficiency and accuracy of the mortise and tenon broaching machine. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a method for optimizing the efficient process parameters of the tenon groove of a turbine disc of a CNC broaching machine.

[0004] The technical solution of the present invention is: a method for optimizing efficient process parameters of a turbine disc tenon groove of a CNC broaching machine; comprising the following steps:

[0005] S1. Mortise and tenon surface performance parameter test

[0006] The mortise and tenon broaching test was carried out to measure the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon under different process parameters, and the relationship between the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon and the process parameters was analyzed.

[0007] S2. Mortise and tenon cutting force modeling

[0008] A cutting force model for mortise and tenon cutting was established, and broaching force tests were carried out to obtain the cutting force coefficient during mortise and tenon cutting.

[0009] S3. Modal Analysis and Stable Region Solution of Tongue and Groove Broaching Machine

[0010] S3-1. Measure and obtain the modal parameters of each point (node) of the workpiece and tool

[0011] 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: (i is a natural number), through modal testing, the modal transfer function of each node of the tool is obtained in turn .

[0012] S3-2. Establishing the kinetic equation

[0013] Considering the influence of broaching speed on damping and stiffness, the established cutting dynamics equation is as follows:

[0014] (5)

[0015] in: is the mass matrix of the cutting system, is the constant M0, and a finite element model can be established for components such as motors and bearings in the cutting system. Its mass matrix can be quickly obtained in the finite element software;

[0016] is the stiffness matrix;

[0017] is the broaching speed,

[0018] G represents the comprehensive influence coefficient of node speed and broaching speed on damping,

[0019] D is the equivalent viscous damping matrix, which is determined by the properties of the material.

[0020] q is the node displacement,

[0021] is the node speed,

[0022] is the node acceleration,

[0023] F(t) is the nodal force vector;

[0024] Then the machining dynamics equation between the tool and the workpiece is:

[0025] ;

[0026] ;

[0027] in: is the mass matrix of the workpiece,

[0028] is the mass matrix of the tool,

[0029] is the damping matrix of the workpiece,

[0030] is the stiffness matrix of the workpiece,

[0031] are the displacements of the workpiece and tool tip,

[0032] , are the speeds of the workpiece and tool tip,

[0033] are the accelerations of the workpiece and tool tip,

[0034] is the force vector of the workpiece,

[0035] is the force vector of the tool tip.

[0036] S3-3. Cutting Depth Analysis

[0037] The formula for calculating the cutting depth is as follows:

[0038] ;

[0039] ;

[0040] ;

[0041] in:

[0042] is the cutting cycle,

[0043] is the dynamic cutting depth,

[0044] is the cutting width,

[0045] is the cutting force coefficient, which can be obtained by fitting the test data through right-angle cutting tests at different cutting depths;

[0046] Performing Laplace transform on the cutting depth h yields:

[0047] ;

[0048] The cutting dynamics equation is converted to:

[0049] ;

[0050] ;

[0051] in: Indicates the cutting depth of the previous tooth of the tool.

[0052] Indicates the cutting depth of the current tooth of the tool.

[0053] Indicates the cutting depth caused by the workpiece offset caused by the current workpiece vibration.

[0054] Indicates the cutting depth caused by the workpiece offset due to the vibration of the workpiece in the previous cycle.

[0055] Denotes: Laplace factor,

[0056] Indicates: the natural frequency of the broaching system,

[0057] Indicates the excitation frequency of the broaching process, which is determined by the broaching speed and the spacing between the broaching teeth, and is the ratio of the broaching speed to the spacing between the broaching teeth;

[0058] N represents the influence coefficient of broaching speed on damping.

[0059] S3-4. Stable region solution

[0060] 1) During the cutting process, under the action of cutting force, the transfer function between different nodes of the tool and the workpiece is:

[0061] ;

[0062] Will After Laplace transformation, we can obtain The relationship is as follows:

[0063] ;

[0064] 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:

[0065] ;

[0066] 2) 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 The Laplace form of the transfer function is obtained by Laplace transform ;

[0067] 3) Basis 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;

[0068] S4. Determine the efficient processing parameters of the mortise and tenon

[0069] S4-1, calculating the stable regions of all the nodes of the broach according to the method in S3-4; and finding the intersection of the stable regions of the different nodes of the broach to obtain the stable region that takes into account the dynamic characteristics of all the teeth on the tool;

[0070] 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;

[0071] S4-3. Using the technical standards of the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise and tenon as constraints, obtain the machining parameter range B;

[0072] S4-4. Calculate the intersection of the process parameter interval A and the processing parameter interval B to obtain a valid process parameter interval.

[0073] Furthermore, in step S1, the relationship between the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon and the processing parameters is established as follows:

[0074] ;

[0075] ;

[0076] ;

[0077] ;

[0078] 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 between the surface roughness, surface hardness, surface residual stress, cutting deformation and machining parameters of the workpiece after machining; is the broaching speed, It is the lift of broach teeth.

[0079] Furthermore, in step S1, the constraints on the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon are as follows:

[0080] ;

[0081] ;

[0082] ;

[0083] ;

[0084] The maximum broaching speed is determined according to the following formula (6): and broach tooth lift :

[0085] ; (6)

[0086] It is the maximum material removal efficiency of the tongue and groove broaching process under the above constraints.

[0087] Furthermore, the surface roughness of the mortise and tenon is in the range of 1.6-3.2 microns; the surface hardness is in the range of 30-40HRc, the surface residual stress is in the range of 400-800Mpa, and the cutting deformation is in the range of -0.12 - 0.12 microns.

[0088] Furthermore, during the broaching test, the tooth lift was 0.06-0.12 mm and the broaching speed was 6-10 m / min.

[0089] Furthermore, step S2 includes:

[0090] S2-1. Establishing a cutting force model for single-tooth broaching

[0091] The workpiece is made of the same material as the mortise and tenon workpiece, and the tool is a single-tooth broach. The 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:

[0092] , (1)

[0093] in is the cutting force on the top cutting edge, is the cutting force of the side cutting edge;

[0094] , (2)

[0095] Among them: h1 is the tooth lift of the broach tooth top, which is equivalent to the cutting depth of the tooth top.

[0096] is the width of the broach teeth,

[0097] is the area cutting force coefficient of the top cutting edge,

[0098] is the cutting force coefficient of the length of the top cutting edge;

[0099] , (3)

[0100] Where: h2 is the tooth lift on the broach tooth side, which is equivalent to the cutting depth on the tooth side.

[0101] The length of the broach tooth side involved in cutting,

[0102] is the area cutting force coefficient of the cutting edge on the tooth side,

[0103] is the cutting force coefficient of the length of the cutting edge on the tooth side;

[0104] Several groups of broaching experiments were carried out to obtain the cutting force coefficients in formulas (1)-(3), and a broaching force model was established when a single tooth in the x-direction of the mortise and tenon was involved in cutting.

[0105] Furthermore, step S2 includes:

[0106] S2-2. Obtaining the total cutting force coefficient

[0107] According to the single tooth cutting force model in S2-1, the tooth top lift, tooth top width, tooth side lift, and tooth side cutting width are set as follows: ;

[0108] The broaching force of a single tooth in the x direction is:

[0109] ,

[0110] ,

[0111] ;

[0112] in: is the cutting force of the top cutting edge of a single tooth of the broach in the x direction;

[0113] is the cutting force of the side cutting edge of a single tooth of the broach in the x direction;

[0114] The broaching force of a single tooth Convert to the following model:

[0115] ; (4)

[0116] Where: h is the tooth lift, is the cutting width of the blade teeth, is the total cutting force coefficient; according to the above formula, calculate the total cutting force coefficient .

[0117] Furthermore, 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.

[0118] Furthermore, considering the actual cutting process of the mortise and tenon and the supporting parameter set, the tooth lift of the broaching tool tooth top and the tool tooth side is set between 0.070 and 0.100 mm, the tooth top cutting width is set between 1 and 2.8 mm, and the width of the broaching tool side is set between 1 and 3 mm; First, the tooth lift and cutting width of the broaching tool tooth top are taken as 0.08 mm and 2.5 mm respectively, the tooth lift of the broaching tool tooth side is 0.07, 0.08, 0.09, 0.1 mm, and the cutting width of the broaching tool tooth side is 1, 1.5, 2, and 2.5 mm respectively. Experiments are carried out to obtain the cutting force coefficient of the broaching tool tooth side, where each cutting force coefficient has multiple values, and the average of the multiple values of the cutting force coefficient is taken; then, the tooth lift and cutting width of the broaching tool side are taken as 0.08 mm and 2 mm respectively, the tooth lift of the broaching tool tooth top is 0.07, 0.08, 0.09, 0.1 mm, and the cutting width of the broaching tool tooth top is 1, 1.5, 2, and 2.5 mm respectively, and the cutting force coefficient of the broaching tool tooth top is obtained; during the calculation process, each cutting force coefficient has multiple values, and the average of the multiple values of the relevant cutting force coefficient is taken; finally, the cutting force coefficient in the x direction is obtained.

[0119] Furthermore, 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.

[0120] Compared with the prior art, the present invention has the following beneficial effects: Based on cutting principles, mechanical vibration, deep learning and other theories, the present invention proposes an efficient process parameter optimization method for the tenon and groove of the turbine disc of a CNC broaching machine. After fully considering the influence of various factors in the actual cutting process of the tenon and groove, the optimized processing parameter range can be obtained, thereby significantly improving the processing efficiency and accuracy of the tenon and groove broaching machine. DETAILED DESCRIPTION

[0121] In order to make the objectives, technical solutions and advantages of the present invention more clear, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessary confusion of the concepts in the present invention.

[0122] Example 1

[0123] This embodiment is a method for optimizing efficient process parameters of turbine disc mortise and tenon grooves on a CNC broaching machine, comprising the following steps:

[0124] S1. Mortise and tenon surface performance parameter test

[0125] Conduct mortise and tenon broaching tests to measure the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise and tenon under different process parameters (tooth lift, broaching speed), and analyze the relationship between the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise and tenon and the process parameters;

[0126] The tooth lift is designed to be 0.06-0.12 mm, and the broaching speed is designed to be 6-10 m / min. The parameter technical standards for the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise and tenon are as follows: the surface roughness range of the mortise and tenon 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.

[0127] 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:

[0128] ;

[0129] ;

[0130] ;

[0131] ;

[0132] in:

[0133] is the surface roughness of the mortise and tenon workpiece;

[0134] is the surface hardness of the workpiece;

[0135] is the residual stress on the workpiece surface;

[0136] is the cutting deformation;

[0137] is the broaching speed,

[0138] is the broach tooth lift;

[0139] 、 、 、 They are the influence indexes between the surface roughness, surface hardness, surface residual stress, cutting deformation and machining parameters of the workpiece after machining.

[0140] The constraints of the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon are:

[0141] ;

[0142] The surface roughness of the mortise and tenon is in the range of 1.6-3.2 microns; i.e. and 1.6 and 3.2 respectively;

[0143] ;

[0144] The surface hardness of the mortise and tenon is 30-40HRc; and 30 and 40 respectively;

[0145] ;

[0146] The residual surface of the mortise and tenon is 400-800Mpa; and 400 and 800 respectively;

[0147] ;

[0148] The size deformation range is -0.12 to +0.12 microns;

[0149] The maximum broaching speed can be determined according to the following formula (6): and broach tooth lift :

[0150] ; (6)

[0151] in It is the maximum material removal efficiency of the tongue and groove broaching process under the above constraints.

[0152] S2. Mortise and tenon cutting force modeling

[0153] A cutting force model for mortise and tenon cutting was established; broaching force tests were conducted to obtain the cutting force coefficients during mortise and tenon cutting.

[0154] S2-1. Establishing a cutting force model for single-tooth broaching

[0155] The workpiece is made of the same material as the mortise and tenon workpiece, and the tool is a single-tooth broach. The 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:

[0156] , (1)

[0157] in is the cutting force on the top cutting edge, is the cutting force of the side cutting edge;

[0158] , (2)

[0159] Among them: h1 is the tooth lift of the broach tooth top, which is equivalent to the cutting depth of the tooth top.

[0160] is the width of the broach teeth,

[0161] is the area cutting force coefficient of the top cutting edge,

[0162] is the cutting force coefficient of the length of the top cutting edge;

[0163] , (3)

[0164] Where: h2 is the tooth lift on the broach tooth side, which is equivalent to the cutting depth on the tooth side.

[0165] The length of the broach tooth side involved in cutting,

[0166] is the area cutting force coefficient of the cutting edge on the tooth side,

[0167] is the cutting force coefficient of the cutting edge length on the tooth side.

[0168] A single-edged broach was used for side-pulling cutting force tests. A single broach can be used to perform cutting tests with different tooth top widths, tooth lifts, and tooth side lifts and widths. By adjusting the vertical height and left-right distance of the broach teeth, the broach's cutting depth and width can be adjusted, yielding different tooth top and side lifts and widths. By conducting multiple broaching experiments, the cutting force coefficients in formulas (1)-(3) can be derived, and a broaching force model for a single tooth in the x-direction of the mortise and tenon groove can be established.

[0169] Specifically, considering the actual cutting process and supporting parameter set for the mortise and tenon groove, the tooth lift of the broach tooth top and tooth side is 0.070-0.100 mm, the tooth top cutting width (cutting edge length) is 1-2.8 mm, and the broach side width (cutting edge length) is 1-3 mm. First, the tooth lift of the broach tooth top and the cutting width remain unchanged, taking values of 0.08 mm and 2.5 mm, respectively. The tooth lift of the broach tooth side is 0.07, 0.08, 0.09, and 0.1 mm, and the cutting width (cutting edge length) of the broach side is 1, 1.5, 2, and 2.5 mm, respectively. The cutting force coefficient of the broach tooth side is obtained. Each cutting force coefficient has multiple values, and the average of the multiple cutting force coefficient values is taken. Secondly, the tooth lift and cutting width on the broaching tool side remain unchanged, and are taken as 0.08 mm and 2 mm respectively. The tooth lift of the broaching tool tooth top is 0.07, 0.08, 0.09, and 0.1 mm. The cutting width (cutting edge length) of the broaching tool tooth top is 1, 1.5, 2, and 2.5 mm respectively. The cutting force coefficient of the broaching tool tooth top is obtained, where each cutting force coefficient has multiple values. The average of the multiple values of the cutting force coefficient is taken; the cutting force coefficient in the x direction can be obtained; similarly, the cutting force coefficients in other directions (y, z) can be obtained.

[0170] S2-2. Obtaining the total cutting force coefficient

[0171] According to the single tooth cutting force model in S2-1, the tooth top lift, tooth top width, tooth side lift, and tooth side cutting width are set as follows: ;

[0172] The broaching force of a single tooth in the x direction is

[0173] ,

[0174] ,

[0175] ;

[0176] in: is the cutting force of the top cutting edge of a single tooth of the broach in the x direction;

[0177] is the cutting force of the side cutting edge of a single tooth of the broach in the x direction;

[0178] The broaching force of a single tooth Transform to the following model

[0179] ; (4)

[0180] Where: h is the tooth lift, is the cutting width of the blade teeth, is the total cutting force coefficient; the total cutting force coefficient can be calculated according to formula (4): .

[0181] S3. Modal Analysis and Stable Region Solution of Tongue and Groove Broaching Machine

[0182] S3-1. Measure and obtain the modal parameters of each point (node) of the workpiece and tool

[0183] 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: (i is a natural number), through modal testing, the modal transfer function of each node of the tool is obtained in turn .

[0184] S3-2. Establishing the kinetic equation

[0185] Considering the influence of broaching speed on damping and stiffness, the established cutting dynamics equation is as follows:

[0186] (5)

[0187] in:

[0188] is the mass matrix of the cutting system, and is the constant M0. The finite element model of the motor, bearing and other components in the cutting system can be established, and their mass matrix can be quickly obtained in the finite element software;

[0189] is the stiffness matrix,

[0190] is the broaching speed,

[0191] G represents the comprehensive influence coefficient of node speed and broaching speed on damping,

[0192] D is the equivalent viscous damping matrix, which is determined by the properties of the material.

[0193] q is the node displacement,

[0194] is the node speed,

[0195] is the node acceleration,

[0196] F(t) is the nodal force vector;

[0197] Then the machining dynamics equation between the tool and the workpiece is:

[0198] ;

[0199] ;

[0200] in: is the mass matrix of the workpiece,

[0201] is the mass matrix of the tool,

[0202] is the damping matrix of the workpiece,

[0203] is the stiffness matrix of the workpiece;

[0204] are the displacements of the workpiece and tool tip,

[0205] , are the speeds of the workpiece and tool tip,

[0206] are the accelerations of the workpiece and tool tip, respectively;

[0207] is the force vector of the workpiece,

[0208] is the force vector of the tool tip.

[0209] S3-3. Cutting Depth Analysis

[0210] The formula for calculating the cutting depth is as follows:

[0211] ;

[0212] ;

[0213] ;

[0214] in: is the cutting cycle,

[0215] is the dynamic cutting depth,

[0216] is the cutting width,

[0217] is the cutting force coefficient, which is obtained by fitting the test data through right-angle cutting tests at different cutting depths.

[0218] Performing Laplace transform on the cutting depth h yields:

[0219] ;

[0220] The cutting dynamics equation is converted to:

[0221] ;

[0222] ;

[0223] in: Indicates the cutting depth of the previous tooth of the tool.

[0224] Indicates the cutting depth of the current tooth of the tool.

[0225] Indicates the cutting depth caused by the workpiece offset caused by the current workpiece vibration.

[0226] Indicates the cutting depth caused by the workpiece deviation caused by the vibration of the workpiece in the previous cycle;

[0227] Denotes: Laplace factor,

[0228] Indicates: the natural frequency of the broaching system,

[0229] Indicates the excitation frequency of the broaching process, which is determined by the broaching speed and the spacing between the broaching teeth, and is the ratio of the broaching speed to the spacing between the broaching teeth;

[0230] N represents the influence coefficient of broaching speed on damping.

[0231] S3-4. Stable region solution

[0232] 1) During the cutting process, under the action of cutting force, the transfer function between different nodes of the tool and the workpiece is:

[0233] ;

[0234] Will After Laplace transformation, we can obtain The relationship is as follows:

[0235] ;

[0236] 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:

[0237] ;

[0238] 2) 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 The Laplace form of the transfer function is obtained by Laplace transform ;

[0239] 3) Basis 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;

[0240] S4. Determine the efficient processing parameters of the mortise and tenon

[0241] S4-1, calculating the stable regions of all the nodes of the broach according to the method in S3-4; and finding the intersection of the stable regions of the different nodes of the broach to obtain the stable region that takes into account the dynamic characteristics of all the teeth on the tool;

[0242] 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. Taking into account the actual deviation, the actual maximum tooth lift is set to 0.6 times the maximum theoretical tooth lift; the optimal process parameter range A is obtained when considering chatter;

[0243] S4-3. Using the technical standards of the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise and tenon as constraints, obtain the machining parameter range B;

[0244] S4-4. Calculate the intersection of the process parameter interval A and the processing parameter interval B to obtain a valid process parameter interval.

[0245] 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 variations of the aforementioned technical features. Without departing from the spirit and scope of the present invention, those skilled in the art can 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 optimizing efficient process parameters of turbine disc mortise and tenon grooves on a CNC broaching machine; characterized in that: The following steps are involved: S1. Mortise and tenon surface performance parameter test Conduct mortise and tenon broaching tests to measure the surface roughness, surface hardness, residual stress, and cutting deformation 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 Establish a cutting force model for mortise and tenon cutting; and conduct broaching force tests to obtain the cutting force coefficient for 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, is the force vector of the workpiece, is the force vector of the tool tip; S3-3. Cutting Depth Analysis The formula for calculating the cutting depth is as follows: ， ， ， in: is the cutting cycle, 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 offset due to the vibration of the workpiece in the previous cycle. Denotes: Laplace factor, Indicates: the natural frequency of the broaching system, Indicates the excitation frequency of the broaching process, which is determined by the broaching speed and the spacing between the broach teeth, and is the ratio of the broaching speed to the spacing between 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 can obtain 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 The Laplace form of the transfer function is obtained by Laplace transform ; 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. Calculate the intersection of the stable regions of the teeth at different nodes on the broach to obtain 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. Using the technical standards of the surface roughness, surface hardness, residual stress, and cutting deformation of the mortise and tenon as constraints, obtain the machining parameter range B; S4-4. Calculate the intersection of the process parameter interval A and the processing parameter interval B to obtain an optimized process parameter interval.

2. The method for optimizing efficient process parameters of turbine disc mortise and tenon grooves on a CNC broaching machine according to claim 1, characterized in that: In step S1, the relationship between the surface roughness, surface hardness, residual stress and cutting deformation of the mortise and tenon and the processing parameters is established 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 between 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 lift of broach teeth.

3. The method for optimizing efficient process parameters of turbine disc tenon groove of CNC broaching machine according to claim 2 is characterized in that: In step S1, the constraints on 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 tongue and groove broaching process under the above constraints.

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

5. The method for optimizing efficient process parameters of turbine disc mortise and tenon grooves on a CNC broaching machine according to claim 3, 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 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. The 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） Among them, 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 a broaching force model was established when a single tooth in the x direction of the mortise and tenon groove participated in cutting.

7. The method for optimizing efficient process parameters of turbine disc mortise and tenon grooves on a CNC broaching machine according to claim 6, 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 ; 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 Convert 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 mortise and tenon grooves on a CNC broaching machine according to claim 1, 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 mortise and tenon grooves on a CNC broaching machine according to claim 8, characterized in that: Taking into account the actual cutting process of the mortise and tenon and the supporting parameter group, the tooth lift of the broaching tool tooth top and the tooth side is between 0.070~0.100 mm, the tooth top cutting width is between 1~2.8 mm, and the width of the broaching tool side is between 1-3 mm; first, the tooth lift and cutting width of the broaching tool tooth top are set to 0.08 mm and 2.5 mm respectively, the tooth lift of the broaching tool tooth side is 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, and the cutting width of the broaching tool side is 1 mm, 1.5 mm, 2 mm respectively, 2.5 mm, and experiments were conducted to obtain the cutting force coefficient of the broach tooth side; then, the tooth lift and cutting width of the broach side were set to 0.08 mm and 2 mm respectively, the tooth lift of the broach tooth top was 0.07 mm, 0.08 mm, 0.09 mm, and 0.1 mm, and the cutting width of the broach tooth top was 1 mm, 1.5 mm, 2 mm, and 2.5 mm respectively, and the cutting force coefficient of the broach tooth top was obtained; 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 mortise and tenon grooves on a 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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