A method of grinding an inducer wheel blade

Abstract

The application discloses a polishing method for an inducer blade, and aims at solving the problems of inconsistent products and limited application range caused by the existing inducer blade modification method. First, the data of the leading line of the blade inlet edge or the leading line of the blade outlet edge is discretized according to the polishing requirement, then the data of the polishing center line of the blade inlet or the polishing center line of the blade outlet is discretized, and finally, the discretized data is used for three-dimensional modeling, and the polishing of the corresponding blade is completed. The method not only improves the production efficiency, but also guarantees the consistency and quality of the products.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an inducer wheel, specifically to a method for grinding inducer wheel blades, which can be used to grind and shape the inlet and outlet of the blades. Background Technology

[0002] In liquid rocket engine turbopumps, the inducer is typically installed before the centrifugal impeller to enhance the turbopump system's resistance to cavitation. During the design and manufacturing process, the inlet blades of the inducer need to be rounded and ground to improve its cavitation performance and suppress cavitation development on the blade surface. At the same time, the outlet blades also need to be ground to ensure the matching effect between the inducer and the downstream centrifugal impeller, thus guaranteeing the turbopump's head and efficiency.

[0003] Existing inducer impellers lack a unified standard for the transitional changes in blade grinding during modeling and production. Especially during production, operators typically use prototypes as a benchmark and rely on experience for grinding and shaping, leading to inconsistent product quality. To address this, Chinese invention patent CN119508262A discloses an inducer impeller and blade shaping method. This method first identifies the guiding region in the non-working surface, then grinds the guiding region, and finally inspects it. The inducer impeller obtained using this method exhibits high cavitation resistance and lower flow resistance on the inlet side. However, this method is only applicable to inducer impellers with high cavitation resistance; it does not address the shaping of the outlet-side blades, thus limiting its applicability. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of existing inducer blade shaping methods, such as the inability to guarantee product consistency and the limited scope of application, and to provide a grinding method for inducer blades.

[0005] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0006] A method for grinding inducer blades, used to grind the inlet and / or outlet of inducer blades, is characterized by including the following steps:

[0007] Step 1: Discretize the data of the blade inlet edge guide line or outlet edge guide line.

[0008] 1.1) Based on the profile parameters of the inlet or outlet of the inducer blade, obtain the two-dimensional polar coordinate data of the blade inlet side guide line or outlet side guide line;

[0009] 1.2) Convert the two-dimensional polar coordinate data described in step 1.1) into corresponding Cartesian coordinate data; the Cartesian coordinate data includes the x-axis coordinate and y-axis coordinate corresponding to each point on the blade inlet guide line or outlet guide line;

[0010] 1.3) Based on the relationship between blade lead and wrap angle, and combined with the blade's inlet lead, middle lead, outlet lead and the corresponding wrap angle, the z-axis coordinates of each point on the blade's inlet or outlet guide line are obtained, thus obtaining the discretized data of the blade's inlet or outlet guide line.

[0011] Step 2: Discretization of the data for the grinding centerline of the blade inlet or outlet.

[0012] 2.1) Based on the preset requirements of the blade inlet or outlet, set the grinding area of ​​the blade inlet or outlet, the total number of grinding curves in the grinding area, and the number of grinding points on each grinding curve;

[0013] 2.2) Combining the two-dimensional polar coordinate data described in step 1.1), determine the radius, length, and angle of the starting center line of each grinding curve, and then obtain the z-axis coordinate of each grinding curve;

[0014] 2.3) Based on step 2.2), the normal thickness, inlet leading edge fillet radius, and blade angle of each grinding point on each grinding curve are calculated sequentially, thereby obtaining the circumferential angle distribution and discretized data of the grinding center line of the blade inlet or outlet;

[0015] Step 3: Based on the discretized data obtained in Step 1 and Step 2, perform 3D modeling or machine tool programming, and complete the grinding of the inducer blades.

[0016] Furthermore, in step 1.1), the expression for the two-dimensional polar coordinate data of the blade inlet edge guide line is as follows:

[0017] , ;

[0018] in, , These represent the radius and angle corresponding to each point on the guide line of the blade inlet, respectively; le_max represents the array length in the two-dimensional polar coordinate data.

[0019] Further, in step 1.2), the expression for the Cartesian coordinate data of the blade inlet guide line is:

[0020] ;

[0021] in, This represents the x-axis coordinate of each point on the guide line at the blade inlet. This represents the y-axis coordinate of each point on the guide line of the blade inlet edge. Indicates the direction of blade rotation.

[0022] Furthermore, in step 1.3), the blade lead s and the wrap angle The relation is:

[0023] ;

[0024] In the formula, Describes a piecewise function, s, These represent the lead and wrap angle corresponding to each point on the blade's inlet or outlet guide line, respectively. For the lead of the inlet section; This refers to the wrap angle of the imported section; For the lead of the exit section; The middle section is the wrap angle, and the middle section is a variable pitch section; Indicates the diameter of the leaf tip; Indicates the blade tip inlet installation angle; Indicates the blade tip outlet installation angle; This is the difference between the wrap angle of the middle section and the wrap angle of the inlet section;

[0025] The z-axis coordinate of each point on the blade inlet guide line is calculated using the following formula:

[0026] ;

[0027] In the above formula, This represents the z-axis coordinate of each point on the guide line of the blade inlet edge; This indicates the tilt angle of the blade.

[0028] Further, in step 2.2), the radius of the polishing curve is calculated using the following formula:

[0029] ;

[0030] In the formula, Let represent the radius of the j-th polishing curve, where j takes values ​​of 1, 2, ..., m; m represents the total number of polishing curves. This represents the radius of the first polishing curve; This indicates the radius of the last polishing curve;

[0031] The length of the grinding curve is calculated using the following formula:

[0032] ;

[0033] In the formula, This represents the length of the j-th polishing curve. Indicates polishing criteria;

[0034] The angle of the starting center line of each polishing curve Based on two-dimensional polar coordinate data, it can be obtained through multiple difference calculations;

[0035] z-axis coordinate of each polishing curve Calculated using the following formula:

[0036] ;

[0037] In the formula, This represents the z-axis coordinate of the j-th polishing curve; This indicates the tilt angle of the blade.

[0038] Further, in step 2.3), the normal thickness of the corresponding grinding point on the grinding curve is calculated using the following formula:

[0039] ;

[0040] In the formula, This represents the normal thickness of the grinding point corresponding to the j-th grinding curve; Indicates the normal thickness of the blade tip; Indicates the normal thickness at the leaf root; Indicates the diameter of the leaf tip; This indicates the diameter of the wheel hub.

[0041] Furthermore, in step 2.3), the blade angle of the grinding section at the inlet of each grinding curve is calculated using the following formula:

[0042] ;

[0043] In the formula, The blade angle of the grinding section at the inlet segment of the j-th grinding curve; Let represent the blade angle at the inlet segment of the j-th grinding curve, and ; The wedge angle generated by the blade during grinding is obtained by solving the following formula:

[0044] ;

[0045] In the formula, This represents the inlet leading edge fillet radius of the j-th grinding curve.

[0046] Further, in step 2.3), the circumferential angle distribution of the grinding center line is as follows:

[0047] ;

[0048] In the formula, This represents the circumferential angle of the k-th grinding point on the j-th grinding curve; This represents the circumferential angle of the first grinding point on the j-th grinding curve; Let k represent the polishing points on the polishing curve, where k takes values ​​of 1, 2, ..., n; and n represent the total number of polishing points on the polishing curve. This represents the circumferential angle of the last grinding point on the j-th grinding curve; This indicates the total wrap angle of the preset grinding curve.

[0049] Further, in step 2.3), the coordinates of the discrete data points of the grinding centerline are: ,in:

[0050] ;

[0051] In the formula, This represents the coordinates of the k-th grinding point on the j-th grinding curve; This represents the change in z-axis coordinate caused by different grinding radii at the leading edge.

[0052] The beneficial effects of this invention are as follows:

[0053] 1. The present invention provides a grinding method for inducer blades. First, according to the grinding requirements, the data of the blade inlet edge guide line or outlet edge guide line are discretized. Then, the data of the blade inlet or outlet grinding center line are discretized. Finally, the discretized data are used to perform three-dimensional modeling and complete the grinding of the corresponding blade. This method not only improves production efficiency, but also ensures product consistency and product quality.

[0054] 2. The grinding method for inducer blades provided by this invention can be used not only for grinding the blade inlet but also for grinding the blade outlet, and has strong applicability and versatility. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the structure of the left-handed inducer inlet in an embodiment of the present invention. In the diagram, the vertical plane pointing inward is the Z+ direction. Indicates the wrap angle of the blade inlet guide line portion;

[0056] Figure 2 This is a schematic diagram of the unfolded structure of the cylindrical surface of the inducer blade in an embodiment of the present invention;

[0057] Figure 3 This is an axial view of the inducer blades in an embodiment of the present invention;

[0058] Figure 4 This is a schematic diagram of the grinding method for the inlet of the inducer blade in an embodiment of the present invention;

[0059] Figure 5 This is a three-dimensional example diagram of grinding the inlet of the inducer blade in an embodiment of the present invention. Detailed Implementation

[0060] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0061] This embodiment provides a grinding method for inducer blades, which can be used to grind the inlet and / or outlet of inducer blades. The grinding method includes the following steps:

[0062] Step 1: Discretize the data of the blade inlet edge guide line or outlet edge guide line.

[0063] 1.1) Based on the profile parameters of the inlet or outlet of the inducer blade, obtain the two-dimensional polar coordinate data of the blade inlet side guide line or outlet side guide line.

[0064] Taking the grinding of the inlet blade of a variable pitch inducer as an example, based on the existing profile parameters of the inlet blade, the two-dimensional polar coordinate data of the blade inlet guide line can be obtained, namely:

[0065] , (1)

[0066] in, , These represent the radius and angle corresponding to each point on the guide line of the blade inlet, respectively; le_max represents the array length in the two-dimensional polar coordinate data, which is determined according to the actual situation.

[0067] 1.2) Convert the two-dimensional polar coordinate data described in step 1.1 into corresponding Cartesian coordinate data. The expression for the Cartesian coordinate data is:

[0068] (2)

[0069] in, This represents the x-axis coordinate of each point on the guide line at the blade inlet. This represents the y-axis coordinate of each point on the guide line of the blade inlet edge. Indicates the direction of blade rotation.

[0070] 1.3) Based on the relationship between blade lead and wrap angle, and combined with the blade's inlet lead, middle lead, outlet lead and the corresponding wrap angle, the z-axis coordinates of each point on the blade's inlet or outlet guide line are obtained, thus obtaining the discretized data of the blade's inlet or outlet guide line.

[0071] For axial coordinates (i.e., z-axis coordinates), we first introduce the correspondence between lead and wrap angle. ,Right now:

[0072] (3)

[0073] In the formula, Describes a piecewise function, s, These represent the lead and wrap angle corresponding to each point on the blade's inlet or outlet leading edge, respectively. For the lead of the inlet section; This refers to the wrap angle of the imported section; For the lead of the exit section; The middle section is the wrap angle, and the middle section is a variable pitch section whose lead varies with the wrap angle; Indicates the diameter of the leaf tip; Indicates the blade tip inlet installation angle; Indicates the blade tip outlet installation angle; This is the difference between the wrap angle of the middle section and the wrap angle of the inlet section.

[0074] Then, the z-axis coordinate of each point on the blade inlet guide line is calculated using the following formula:

[0075] (4)

[0076] In the above formula, This represents the z-axis coordinate of each point on the guide line of the blade inlet edge; This indicates the tilt angle of the blade.

[0077] The calculation method for the discretized data of the blade exit edge guideline is the same as above, and will not be repeated here. It should be noted that the subscript for each parameter on the exit edge is 'out', meaning the radius corresponding to each point on the blade exit edge guideline is... , angle is The coordinates of each point on the exit guide line are ( , , ).

[0078] Step 2: Discretization of the data for the grinding centerline of the blade inlet or outlet.

[0079] 2.1) Based on the preset requirements for blade inlet or outlet, set the grinding zones for blade inlet or outlet, the total number of grinding curves *m* in the grinding zones, and the number of grinding points *n* on each grinding curve. Also, provide the grinding criteria. L represents the length of the corresponding grinding curve, D represents the diameter of the corresponding grinding curve, and grinding criteria. The value must be selected to ensure that the grinding section is within the range of the inlet equal pitch section.

[0080] 2.2) Combining the two-dimensional polar coordinate data described in step 1.1, determine the radius, length and angle of the starting center line of each grinding curve, and then obtain the z-axis coordinate of each grinding curve.

[0081] The radius of the grinding curve described in this embodiment is calculated using the following formula:

[0082] (5)

[0083] In the formula, Let represent the radius of the j-th polishing curve, where j takes values ​​of 1, 2, ..., m; m represents the total number of polishing curves. This represents the radius of the first polishing curve; This indicates the radius of the last polishing curve.

[0084] According to the polishing guidelines, the length of the polishing curve is calculated using the following formula:

[0085] (6)

[0086] In the formula, This represents the length of the j-th polishing curve. This indicates the polishing criteria.

[0087] according to and The curve changes, the angle of the starting center line of each polishing curve Based on two-dimensional polar coordinate data, it can be obtained through multiple difference calculations.

[0088] z-axis coordinate of each polishing curve Calculated using the following formula:

[0089] (7)

[0090] In the formula, This represents the z-axis coordinate of the j-th polishing curve; This indicates the tilt angle of the blade.

[0091] 2.3) Based on step 2.2), the normal thickness, inlet leading edge fillet radius, and blade angle of each grinding point on each grinding curve are obtained sequentially, resulting in the circumferential angle distribution and discretized data of the blade inlet or outlet grinding centerline, specifically:

[0092] The normal thickness at the corresponding grinding point on the grinding curve varies linearly with the radius, and the variation law is as follows:

[0093] (8)

[0094] In the formula, This represents the normal thickness of the grinding point corresponding to the j-th grinding curve; Indicates the normal thickness of the blade tip; Indicates the normal thickness at the leaf root; Indicates the diameter of the leaf tip; This indicates the diameter of the wheel hub.

[0095] The blade angle of the grinding section at the inlet of each grinding curve is calculated using the following formula:

[0096] (9)

[0097] In the formula, Let the blade angle of the grinding section be the inlet segment of the j-th grinding curve; Let be the blade angle of the inlet segment of the j-th grinding curve, and ; The wedge angle generated during blade grinding affects the local placement angle of the blade and can be obtained by the following formula:

[0098] (10)

[0099] In the formula, This represents the inlet leading edge fillet radius of the j-th grinding curve, which can be compared with... It can be proportional or a constant value; here we take a constant value as an example, that is... .

[0100] In summary, the circumferential angle distribution of the grinding center line is as follows:

[0101] (11)

[0102] In the formula, This represents the circumferential angle of the k-th grinding point on the j-th grinding curve; This represents the circumferential angle of the first grinding point on the j-th grinding curve; Let k represent the polishing points on the polishing curve, where k takes values ​​of 1, 2, ..., n; and n represent the total number of polishing points on the polishing curve. This represents the circumferential angle of the last grinding point on the j-th grinding curve; This indicates the total wrap angle of the preset grinding curve.

[0103] The coordinates of the discrete data points of the grinding centerline are ,in:

[0104] (12)

[0105] In the formula, This represents the change in z-axis coordinate caused by different grinding radii at the leading edge.

[0106] Step 3: Based on the discretized data obtained in Step 1 and Step 2, perform 3D modeling or machine tool programming, and complete the grinding of the inducer blades.

[0107] Combination Figures 1 to 5 The following explanation uses the grinding of the inlet of a left-handed inducer blade with a known constant pitch as an example. The blade of this inducer is left-handed, and the blade tip diameter is... Wheel hub diameter Blade lead Normal thickness of the leaf tip normal thickness at the leaf root ,inclination Imported guide edge corner .

[0108] Step 1: Discretization of the blade inlet edge guide line data

[0109] First, the inlet and outlet installation angles of the blade tip can be calculated. .

[0110] Next, by dividing the radius into several parts radially, the discrete points of the inlet guide edge can be obtained. Here, the inner and outer radii are extended outwards to ensure the integrity of the curve. The array length le_max=18, so the two-dimensional polar coordinate data of the inlet guide line is as follows:

[0111]

[0112] By transforming the coordinates, the coordinates of the leading edge in the Cartesian coordinate system can be obtained. ,Right now:

[0113]

[0114] Step 2, Discretization of data for the blade inlet grinding centerline

[0115] Set the number of polishing curves to m=7, the number of polishing points on each polishing curve to n=60, and the total wrap angle of the polishing curves. Polishing principles Therefore, the grinding radius and length of the corresponding grinding curve can be calculated. ,Right now:

[0116]

[0117] At the same time, by calculating the cubic spline difference, we can obtain the result... The corresponding grinding curve starting centerline angle (The angle is in radians) We have:

[0118]

[0119] Combining and Substituting this into equation (4) yields the corresponding z-axis coordinates, i.e., the starting coordinates of grinding curves with different radii are... ,in:

[0120] .

[0121] The normal thickness of the blade at different grinding radii can be further calculated using equation (8). ,Right now:

[0122] The radius of the inlet leading edge fillet at the given grinding radius Here, a fixed value is chosen, that is:

[0123]

[0124] Solving for different blade radii Inlet section blade angle The unit is radians, and:

[0125]

[0126] Solve for different radii according to equation (10) wedge angle at the starting point The unit is radians.

[0127]

[0128] The blade angle after grinding can be obtained from the blade angle before grinding and the wedge angle produced by grinding. The unit is radians, and .

[0129] At this point, the information of the first point of all the grinding curves has been obtained. Next, we will solve for the coordinates of each grinding line after discretization. The total amount of data is m×n.

[0130] The circumferential distribution of grinding points on each grinding curve is as follows: The unit is radians, that is:

[0131]

[0132] The radius and circumference of each grinding point are known. According to equation (12), the discrete data of all grinding curves can be obtained.

[0133] Step 3: Based on the discretized data obtained in Steps 1 and 2, perform 3D modeling. Figure 5 (As shown) or machine tool programming, and complete the grinding of the inducer blades.

[0134] This invention targets variable pitch (including constant pitch, and constant / variable / constant pitch) inducers. By determining the grinding angle and the minimum thickness of the leading (trailing) edge of the blade based on the axial section profile of the inducer blade, the coordinate profile of the grinding surface can be given. At the same time, grinding can be performed according to the blade inlet and outlet as required. This method not only improves the applicability of existing technologies, but also improves the production quality and product consistency of the products.

[0135] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for grinding inducer blades, used to grind the inlet and / or outlet of inducer blades, characterized by comprising the following steps: Step 1: Discretize the data of the blade inlet edge guide line or outlet edge guide line. 1.1) Based on the profile parameters of the inlet or outlet of the inducer blade, obtain the two-dimensional polar coordinate data of the blade inlet side guide line or outlet side guide line; 1.2) Convert the two-dimensional polar coordinate data described in step 1.1) into corresponding Cartesian coordinate data; the Cartesian coordinate data includes the x-axis coordinate and y-axis coordinate corresponding to each point on the blade inlet guide line or outlet guide line; 1.3) Based on the relationship between blade lead and wrap angle, and combined with the blade's inlet lead, middle lead, outlet lead and the corresponding wrap angle, the z-axis coordinates of each point on the blade's inlet or outlet guide line are obtained, thus obtaining the discretized data of the blade's inlet or outlet guide line. Step 2: Discretization of the data for the grinding centerline of the blade inlet or outlet. 2.1) Based on the preset requirements of the blade inlet or outlet, set the grinding area of ​​the blade inlet or outlet, the total number of grinding curves in the grinding area, and the number of grinding points on each grinding curve; 2.2) Combining the two-dimensional polar coordinate data described in step 1.1), determine the radius, length, and angle of the starting center line of each grinding curve, and then obtain the z-axis coordinate of each grinding curve; 2.3) Based on step 2.2), the normal thickness, inlet leading edge fillet radius, and blade angle of each grinding point on each grinding curve are calculated sequentially, thereby obtaining the circumferential angle distribution and discretized data of the grinding center line of the blade inlet or outlet; Step 3: Based on the discretized data obtained in Step 1 and Step 2, perform 3D modeling or machine tool programming, and complete the grinding of the inducer blades.

2. The grinding method for the inducer blades according to claim 1, characterized in that: In step 1.1), the expression for the two-dimensional polar coordinate data of the blade inlet guide line is as follows: ， ； in, , These represent the radius and angle corresponding to each point on the guide line of the blade inlet, respectively; le_max represents the array length in the two-dimensional polar coordinate data.

3. The grinding method for the inducer blades according to claim 2, characterized in that: In step 1.2), the expression for the Cartesian coordinate data of the blade inlet guide line is: ； in, This represents the x-axis coordinate of each point on the guide line at the blade inlet. This represents the y-axis coordinate of each point on the guide line of the blade inlet edge. Indicates the direction of blade rotation.

4. The grinding method for the inducer blades according to claim 3, characterized in that: In step 1.3), the blade lead s and the wrap angle The relation is: ； In the formula, Describes a piecewise function, s, These represent the lead and wrap angle corresponding to each point on the blade's inlet or outlet guide line, respectively. For the lead of the inlet section; This refers to the wrap angle of the imported section; For the lead of the exit section; The middle section is the wrap angle, and the middle section is a variable pitch section; Indicates the diameter of the leaf tip; Indicates the blade tip inlet installation angle; Indicates the blade tip outlet installation angle; This is the difference between the wrap angle of the middle section and the wrap angle of the inlet section; The z-axis coordinate of each point on the blade inlet guide line is calculated using the following formula: ； In the above formula, This represents the z-axis coordinate of each point on the guide line of the blade inlet edge; This indicates the tilt angle of the blade.

5. The grinding method for the inducer blades according to claim 4, characterized in that: In step 2.2), the radius of the polishing curve is calculated using the following formula: ； In the formula, Let represent the radius of the j-th polishing curve, where j takes values ​​of 1, 2, ..., m; m represents the total number of polishing curves. This represents the radius of the first polishing curve; This indicates the radius of the last polishing curve; The length of the grinding curve is calculated using the following formula: ； In the formula, This represents the length of the j-th polishing curve. Indicates polishing criteria; The angle of the starting center line of each polishing curve Based on two-dimensional polar coordinate data, it can be obtained through multiple difference calculations; The z-axis coordinate of each grinding curve is calculated using the following formula: ； In the formula, This represents the z-axis coordinate of the j-th polishing curve; This indicates the tilt angle of the blade.

6. The grinding method for the inducer blades according to claim 5, characterized in that: In step 2.3), the normal thickness of the corresponding grinding point on the grinding curve is calculated using the following formula: ； In the formula, This represents the normal thickness of the grinding point corresponding to the j-th grinding curve; Indicates the normal thickness of the blade tip; Indicates the normal thickness at the leaf root; Indicates the diameter of the leaf tip; This indicates the diameter of the wheel hub.

7. The grinding method for the inducer blades according to claim 6, characterized in that: In step 2.3), the blade angle of the grinding section at the inlet of each grinding curve is calculated using the following formula: ； In the formula, The blade angle of the grinding section at the inlet segment of the j-th grinding curve; Let represent the blade angle at the inlet segment of the j-th grinding curve, and ; The wedge angle generated by the blade during grinding is obtained by solving the following formula: ； In the formula, This represents the inlet leading edge fillet radius of the j-th grinding curve.

8. The grinding method for the inducer blades according to claim 7, characterized in that: In step 2.3), the circumferential angle distribution of the grinding center line is as follows: ； In the formula, This represents the circumferential angle of the k-th grinding point on the j-th grinding curve; This represents the circumferential angle of the first grinding point on the j-th grinding curve; This represents the polishing point on the polishing curve, where k takes values ​​of 1, 2, ..., n; n represents the total number of polishing points on the curve. This represents the circumferential angle of the last grinding point on the j-th grinding curve; This indicates the total wrap angle of the preset grinding curve.

9. The grinding method for the inducer blades according to claim 8, characterized in that: In step 2.3), the coordinates of the discrete data points of the grinding centerline are: ,in: ； In the formula, This represents the coordinates of the k-th grinding point on the j-th grinding curve; This represents the change in z-axis coordinate caused by different grinding radii at the leading edge.

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