A simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes

Abstract

This invention relates to the field of metal processing technology and discloses a simulation method for the surface morphology of grinding with mixed-size CBN grinding wheels. The method involves setting workpiece motion parameters and abrasive geometric parameters, simulating the workpiece and the mixed-size grinding wheel, and determining the trajectory equation of a specific abrasive grain in the global coordinate system based on the workpiece surface analysis domain, workpiece motion parameters, and abrasive geometric parameters. The method then obtains the trajectory scatter point coordinate matrix showing the mapping relationship between the region containing the abrasive grain and the workpiece surface, and maps and obtains the minimum coordinate value. This mapping process is repeated for all abrasive grains, and the workpiece surface roughness is obtained based on all minimum coordinate values. Finally, the workpiece surface roughness is compared with a preset roughness, and the abrasive geometric parameters are adjusted based on the comparison results until the obtained workpiece surface roughness is less than the preset roughness. This method solves the problem of unreasonable abrasive grain size ratio and abrasive density ratio design in existing mixed-size grinding wheels.

Description

Technical Field

[0001] This invention relates to the field of metal processing technology, and in particular to a simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes. Background Technology

[0002] When grinding titanium microalloyed steel, traditional single-grit superhard abrasive wheels are prone to abrasive grain passivation, breakage, and even detachment due to uneven grinding stress distribution, severely affecting wheel dressing frequency and grinding efficiency. While fine-grit abrasive wheels can achieve high-quality surfaces, the abrasive grains wear quickly, requiring frequent wheel dressing and resulting in low processing efficiency. Using coarse-grit diamond wheels can improve material removal rates, but the unevenness of abrasive grain edge development on the surface of coarse-grit wheels leads to poor workpiece surface quality, failing to meet the high surface quality requirements of high-performance devices.

[0003] The existing conventional processing method is to use the complementary advantages of abrasive grains of different sizes to improve grinding efficiency and machining accuracy. However, based on this, when designing mixed-grain grinding wheels, the impact on workpiece grinding is quite different under the conditions of different abrasive grain size ratios and abrasive grain density ratios on the surface. An unreasonable abrasive grain size ratio and abrasive grain density ratio cannot effectively complete the workpiece with the predetermined target, resulting in unnecessary workpiece wear and energy consumption. Summary of the Invention

[0004] This invention provides a simulation method for the surface morphology of grinding with mixed-size CBN grinding wheels, in order to solve the problem of unreasonable design of abrasive particle size ratio and abrasive particle density ratio in existing mixed-size grinding wheels.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] This invention provides a simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes, comprising the following steps:

[0007] Step 1: Set the workpiece motion parameters and abrasive geometric parameters, simulate the workpiece to be processed and the mixed-size grinding wheel composed of coarse and fine abrasive grains, and obtain the workpiece surface analysis domain. Based on the workpiece surface analysis domain, the workpiece motion parameters and abrasive geometric parameters, determine the trajectory equation of a certain abrasive grain on the surface of the mixed-size grinding wheel in the global coordinate system.

[0008] When simulating a grinding wheel with a mixed particle size composed of coarse and fine abrasive grains, the following constraint applies: the center-to-center distance between any two abrasive grains is greater than the sum of the radii of the mixed abrasive grains, as expressed by the following formula:

[0009] ;

[0010] in, This represents the distance between the centers of any two abrasive grains; Indicates the abrasive grains in any two abrasive grains , Indicates the abrasive grains in any two abrasive grains , The value range is 1 to ; This indicates the average diameter of the coarse-grained abrasive grains. Indicates the average diameter of fine-grained abrasive grains;

[0011] Specifically, the mixed-size abrasive distribution simultaneously satisfies the following two key conditions: (1) abrasives of different sizes do not interfere with each other in three-dimensional space; (2) each abrasive can effectively participate in the grinding process. This controllable abrasive arrangement not only avoids the failure of fine-grained abrasives due to coverage, but also improves the overall grinding performance of the grinding wheel.

[0012] Step 2: Based on the trajectory equation described in Step 1, obtain the trajectory scatter coordinate matrix of the mapping relationship between the region where a certain abrasive grain is located on the surface of the mixed-size grinding wheel and the workpiece surface. Map the trajectory scatter coordinate matrix to the analysis domain of the workpiece surface and save the lowest coordinate value therein.

[0013] Step 3: Repeat steps 1 to 2 to map the coordinate matrix of the scatter points corresponding to the abrasive grains on the surface of all mixed-size grinding wheels, and obtain the workpiece surface roughness based on the lowest value of all coordinates.

[0014] Step 4: Compare the workpiece surface roughness with the preset roughness, and adjust the abrasive geometry parameters based on the comparison results until the obtained workpiece surface roughness is less than the preset roughness.

[0015] The abrasive geometric parameters in steps 1 and 4 are the particle size ratio, density ratio, and cutting edge height of the coarse-grained abrasive particles to the fine-grained abrasive particles.

[0016] The above design effectively avoids the problem of abrasive grain overlap failure caused by differences in grain size in mixed-grain grinding wheels. By precisely controlling the spatial distribution of abrasive grains, it ensures that fine-grained abrasive grains are not completely covered by coarse-grained abrasive grains and fail, thereby fully leveraging the synergistic grinding effect of mixed-grained abrasive grains. The mixed-grained abrasive grains are randomly and uniformly distributed on the grinding wheel surface until a specified number of mixed-grained abrasive grains are distributed in a unit area without interference.

[0017] This method provides a simulation-based theoretical basis for optimizing the abrasive grain ratio coefficient of mixed-size grinding wheels, and helps to establish the correlation between grinding process parameters, grinding wheel geometry, and workpiece morphology evolution. It transforms traditional experience-based trial-and-error grinding wheel design into a precise optimization model based on quantitative indicators. This effectively addresses the cost of experimental trial-and-error in mixed-size grinding wheel abrasive grain ratio design while providing a reliable mixed-size grinding wheel processing solution to meet machining requirements.

[0018] Furthermore, during step 4, the theoretical removal volume of the workpiece surface is calculated based on the lowest value of all saved coordinates, and the material removal efficiency is calculated by comparing it with the simulated residual volume of the workpiece. The distribution density ratio of coarse abrasive grains to fine abrasive grains is adjusted according to the material removal efficiency until the material removal efficiency reaches the preset material removal value.

[0019] Through the above design, by calculating the difference between the theoretical volume of the workpiece fed by the grinding wheel and the residual volume of the simulated workpiece morphology, the material removal efficiency of the mixed-size grinding wheel under single-feed conditions can be obtained. A quantifiable evaluation benchmark is established for the processing efficiency of the mixed-size grinding wheel from the perspective of material removal efficiency, thus providing a scientific basis for the optimal selection of abrasive particle size distribution parameters in the mixed-size grinding wheel.

[0020] Furthermore, when simulating a mixed-grain grinding wheel composed of coarse and fine abrasive particles, the coarse and fine abrasive particles are set to random shapes.

[0021] The shapes include triangles, quadrilaterals, pentagons, and hexagons.

[0022] Furthermore, when simulating a mixed-grain grinding wheel composed of coarse and fine abrasive grains, a threshold for the edge height is set to simulate the surface morphology of the grinding wheel after laser dressing, and the tips of the coarse and fine abrasive grains are cut off.

[0023] The threshold value for the cutting edge height is set based on the plane of the grinding wheel bond and includes the following constraints:

[0024] ;

[0025] in, This indicates the set threshold for the blade extension height.

[0026] By introducing differences in abrasive grain shape, the design overcomes the limitations of traditional circular or spherical abrasive grain models, more accurately reproducing the irregular geometric characteristics of actual abrasive grains. Utilizing a set threshold for abrasive grain exit height, the design achieves height equalization of mixed-size abrasive grains, allowing as many abrasive grains as possible to participate in the collaborative cutting process, increasing the effective number of abrasive grains per unit area. This ensures that the abrasive grain clusters exhibit a natural distribution, better conforming to the cutting edge characteristics of actual abrasive grains, which is beneficial for accurately simulating the material removal mechanism during grinding. This effectively improves the consistency between the simulated grinding wheel morphology and the actual grinding wheel, laying a reliable geometric foundation for the subsequent accurate simulation of grinding performance.

[0027] Furthermore, the trajectory equation of a certain abrasive grain in the global coordinate system is obtained through the following steps:

[0028] A local coordinate system is constructed based on the workpiece motion parameters of the grinding wheel and the geometric parameters of the abrasive grain. The trajectory equation corresponding to the abrasive grain is obtained based on the local coordinate system, and the trajectory equation in the global coordinate system is obtained based on the trajectory equation in the local coordinate system.

[0029] The construction of the trajectory equation in the local coordinate system specifically includes: constructing the trajectory equation of any abrasive grain moving in a circular and translational manner on the grinding wheel over time in the local coordinate system based on the workpiece motion parameters and abrasive grain geometric parameters.

[0030] Through the above design, the grinding process of a mixed-grain size grinding wheel can be viewed as the superposition of the wheel's rotational motion and the workpiece's feed motion. The cutting trajectories of the two abrasive grains interfere with each other, and the grooves left by the fine-grained abrasive grains during grinding may be covered by the coarse-grained abrasive grains within the same feed path. Therefore, constructing the motion trajectory of the mixed-grain size abrasive grains helps to accurately characterize the unique multi-grain size synergistic grinding mechanism of mixed-grain size grinding wheels.

[0031] Furthermore, the trajectory scatter point coordinate matrix is ​​obtained by substituting the workpiece motion parameters of the grinding wheel and the abrasive geometric parameters into the trajectory equation to obtain the trajectory scatter point coordinate matrix of the mapping relationship between the region where any abrasive grain is located on the surface of the mixed-size grinding wheel and the workpiece surface.

[0032] Through the above design, the motion parameters of the grinding wheel and the geometric parameters of the abrasive grains are introduced to effectively characterize the differences in motion characteristics of abrasive grains of different sizes during the cutting process. Considering the circumferential distribution characteristics of mixed-size abrasive grains on the grinding wheel, a functional relationship of "abrasive grain ratio - circumferential spacing - surface profile" is constructed, thereby significantly improving the prediction accuracy of the workpiece surface morphology.

[0033] Furthermore, obtaining the workpiece surface roughness based on all the lowest coordinate values ​​includes: constructing and saving the lowest coordinate values ​​corresponding to all abrasive grains into the analysis domain coordinate matrix, forming workpiece surface morphology data based on the analysis domain coordinate matrix, and obtaining the workpiece surface roughness based on the workpiece surface morphology data.

[0034] The above design allows for the acquisition of workpiece surface morphology data, which helps reflect the microscopic morphological characteristics of the workpiece surface and the material removal mechanism of mixed-size abrasive grains, and elucidates the intrinsic relationship between abrasive grain distribution characteristics and the evolution of cutting marks on the workpiece surface. Based on the acquired workpiece surface roughness values ​​and material removal efficiency, a quantitative correlation between the dual objectives of "machining efficiency and surface quality" for mixed-size abrasive wheels has been achieved for the first time.

[0035] Furthermore, the grinding wheel workpiece motion parameters include grinding depth, grinding wheel linear speed, and workpiece feed speed;

[0036] The abrasive geometric parameters include abrasive shape, abrasive particle size ratio, abrasive density ratio, and abrasive edge height.

[0037] Through the above design, various parameters in the grinding process are systematically set to ensure that the contact state between the abrasive grains and the workpiece during the simulation is highly consistent with the actual machining conditions at the grinding mechanism level. This allows for a more accurate simulation of the differentiated cutting behavior of mixed-size grinding wheels caused by different abrasive grain geometric parameters. The simulation results can directly guide the control and optimization of key proportioning parameters in the preparation of mixed-size grinding wheels.

[0038] Furthermore, based on the lowest coordinate values ​​in step 3, the peak value of the workpiece surface protrusion, the peak value of the workpiece groove width, and the root mean square value of the height difference are calculated to evaluate the mixed-size grinding wheel.

[0039] The peak value of the protrusion on the workpiece surface, the peak value of the workpiece groove width, and the root mean square value of the height difference are all evaluated based on preset thresholds.

[0040] When the peak value of the protrusion on the workpiece surface exceeds the corresponding preset threshold, the abrasive particle size ratio or density ratio is adjusted.

[0041] When the peak value of the protrusion on the workpiece surface exceeds the corresponding preset threshold, it indicates that the distribution of abrasive grains on the grinding wheel surface is too discrete, resulting in uneven removal of workpiece material. The number of fine abrasive grains should be increased or the size of coarse abrasive grains should be reduced to improve the grinding wheel's ability to refine the workpiece surface.

[0042] When the peak width of the workpiece groove exceeds the corresponding preset threshold, the abrasive grain protrusion height is adjusted.

[0043] When the peak value of the workpiece groove width exceeds the preset average value of the workpiece surface contour, it indicates that the edge height of the abrasive grain is too low, which leads to an increase in the size of the residual groove formed by grinding. The edge height of the abrasive grain should be appropriately increased to reduce the width of the workpiece surface groove.

[0044] When the root mean square value of the height difference exceeds the corresponding preset threshold, the abrasive grain exit height is adjusted.

[0045] When the root mean square value of the height difference is greater than the preset value, it indicates that the workpiece surface shows large-scale grinding marks locally. The worse the contour uniformity, the more appropriate the cutting edge height of the abrasive should be reduced to improve the contour flatness of the workpiece surface and improve the material removal efficiency.

[0046] Through the above design, the comprehensive grinding performance of mixed-size grinding wheels is evaluated by quantitatively analyzing indicators such as the peak value of workpiece surface protrusions, the peak value of workpiece groove width, and the root mean square value of height difference, combined with the characterization of grinding wheel geometry and workpiece surface morphology. This study explores the influence of uniform distribution of mixed-size abrasive grains on workpiece surface morphology, summarizes the mathematical correlation between the synergistic grinding mechanism of mixed-size abrasive grains and surface quality, and establishes the mathematical relationship between grinding wheel / workpiece motion parameters / abrasive grain geometric parameters and the surface roughness value.

[0047] Beneficial effects:

[0048] This invention provides a simulation method for the surface morphology of mixed-size CBN grinding wheels. The method simulates and obtains trajectory equations based on the workpiece motion parameters and abrasive geometric parameters. Then, based on these trajectory equations, the motion trajectories of the mixed abrasive grains are mapped to obtain the simulation results of the workpiece surface contour, achieving accurate characterization of the workpiece morphology after grinding with mixed-size grinding wheels. By adjusting variable parameters, the influence of the complementary advantages of different abrasive grain sizes on the surface quality and processing efficiency is explored, providing a theoretical basis for optimizing the mixed-size grinding wheel process.

[0049] For the first time, the geometric characteristics of mixed-grain grinding wheels are quantified using abrasive ratio, density ratio, and abrasive tip height. Compared to grinding wheels with uniform single-grain abrasives, establishing the intrinsic correlation between abrasive ratio parameters, grinding parameters, workpiece material removal, and surface creation mechanisms in mixed-grain grinding wheels allows for flexible adjustment of the processing strategy based on the characteristics and requirements of actual grinding conditions. This solves the problem that the design of abrasive ratio and density ratio in mixed-grain grinding wheels could only be determined through costly trial-and-error methods. Attached Figure Description

[0050] Figure 1 This is a flowchart illustrating a simulation method for the surface morphology of a mixed-size CBN grinding wheel according to an embodiment of the present invention.

[0051] Figure 2 This is a schematic diagram of the workpiece morphology of a mixed-particle-size grinding wheel according to an embodiment of the present invention at abrasive particle size ratios of 0.4 and 0.56;

[0052] Figure 3 This is a schematic diagram of the workpiece morphology of a mixed-particle-size grinding wheel according to an embodiment of the present invention at abrasive particle size ratios of 0.67 and 0.8;

[0053] Figure 4 This is a schematic diagram of the workpiece morphology of a mixed-particle-size grinding wheel according to an embodiment of the present invention at a particle density ratio of 0.5 and 1.

[0054] Figure 5 This is a schematic diagram of the workpiece morphology of a mixed-particle-size grinding wheel according to an embodiment of the present invention at abrasive density ratios of 1.5 and 2. Detailed Implementation

[0055] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0057] See Figure 1 This application provides a simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes, comprising the following steps:

[0058] Step 1: Set the workpiece motion parameters and abrasive geometric parameters, simulate the workpiece to be processed and the mixed-size grinding wheel composed of coarse and fine abrasive grains, and obtain the workpiece surface analysis domain. Based on the workpiece surface analysis domain, the workpiece motion parameters and abrasive geometric parameters, determine the trajectory equation of a certain abrasive grain on the surface of the mixed-size grinding wheel in the global coordinate system.

[0059] Abrasive geometry parameters include abrasive shape, abrasive particle size ratio, abrasive density ratio, and abrasive edge height.

[0060] Among them, the abrasive particle size ratio is This is expressed by the following formula: ;

[0061] in, This indicates the average diameter of the fine-grained abrasive grains. This indicates the average diameter of coarse-grained abrasive particles;

[0062] abrasive density ratio This is expressed by the following formula: ;

[0063] in, This indicates the density of fine-grained abrasive particles. This indicates the density of coarse-grained abrasive particles;

[0064] Specifically, based on the total volume of the abrasive layer With the total volume of abrasive particles and the total volume distribution coefficient of the abrasive layer The following formula can be obtained:

[0065] ;

[0066] Based on this formula, combined with the average volume of coarse-grained abrasive grains... Average volume of fine-grained abrasive grains The derived formula for the number of abrasive grains of the two grain sizes can further express the ratio of abrasive grain densities. The specific formula is as follows:

[0067] ;

[0068] ;

[0069] in, This indicates the number of coarse-grained abrasive particles. Indicates the number of fine-grained abrasive particles. This indicates the unit volume of a grinding wheel with mixed particle sizes. Indicates the abrasive particle volume distribution coefficient;

[0070] abrasive grain exit height with It is indicated that when setting the abrasive grain tip height, the grinding wheel bond plane is used as a reference to simulate the surface morphology of the grinding wheel after laser dressing, and the tips of coarse and fine abrasive grains are cut off.

[0071] And includes the following constraints:

[0072] ;

[0073] Regarding the abrasive grain shape, set random shapes for coarse and fine abrasive grains, including triangles, quadrilaterals, pentagons, and hexagons.

[0074] When simulating a grinding wheel with a mixed particle size composed of coarse and fine abrasive grains, the following constraint applies: the center-to-center distance between any two abrasive grains is greater than the sum of the radii of the mixed abrasive grains, as expressed by the following formula:

[0075] ;

[0076] in, This represents the distance between the centers of any two abrasive grains; Indicates the abrasive grains in any two abrasive grains , Indicates the abrasive grains in any two abrasive grains , The value range is 1 to ; This indicates the average diameter of the coarse-grained abrasive grains. This indicates the average diameter of fine-grained abrasive particles.

[0077] The grinding wheel workpiece motion parameters include grinding depth, grinding wheel linear speed, and workpiece feed rate;

[0078] The trajectory equation of a certain abrasive particle in the global coordinate system is obtained through the following steps:

[0079] A local coordinate system is constructed based on the workpiece motion parameters of the grinding wheel and the geometric parameters of the abrasive grain. The trajectory equation corresponding to the abrasive grain is obtained based on the local coordinate system, and the trajectory equation in the global coordinate system is obtained based on the trajectory equation in the local coordinate system.

[0080] The construction of the trajectory equation in the local coordinate system specifically includes: based on the workpiece motion parameters and abrasive grain geometric parameters, constructing the trajectory equation of any abrasive grain moving in a circular motion on the grinding wheel over time in the local coordinate system, expressed by the following formula:

[0081] ;

[0082] in, Represents any point on the surface of the grinding wheel To coordinates, Represents any point on the surface of the grinding wheel To coordinates, This indicates the cutting time of the abrasive grains. This indicates the rotation angle of the grinding wheel per unit time. Indicates the workpiece feed rate. Indicates the linear velocity of the grinding wheel. The rotational cutting radius of the abrasive grain is the sum of the radius of the grinding wheel matrix and the height of the two types of abrasive grains protruding from the grinding wheel surface.

[0083] Because the angle through which the cutting edge rotates from entry to exit is very small, there is... Therefore, the above formula can be expressed as:

[0084] ;

[0085] Integrating the contact area between the abrasive grain and the workpiece along the cutting direction, we can obtain the formula for the volume of material removed from the workpiece by a single abrasive grain:

[0086] ;

[0087] in, and These represent the contact cross-sectional areas between abrasive grains of different sizes and the workpiece. This is the contact arc length between the abrasive grain and the workpiece.

[0088] The simulated workpiece in the model is processed using the same process parameters as the target workpiece in actual machining, ensuring that the simulation results accurately map the surface morphology characteristics of the workpiece under real machining conditions. Through multi-parameter coupling analysis, the model can accurately predict the surface profile characteristics under different abrasive particle ratios. This model can systematically evaluate the impact of different parameter combinations on machining quality, avoiding the limitations of single-variable analysis and significantly reducing R&D costs.

[0089] Step 2: Based on the trajectory equation in Step 1, obtain the trajectory scatter coordinate matrix of the mapping relationship between the region where a certain abrasive grain is located on the surface of the mixed-size grinding wheel and the workpiece surface. Map the trajectory scatter coordinate matrix to the workpiece surface analysis domain and save the lowest coordinate value.

[0090] The trajectory scatter point coordinate matrix is ​​obtained as follows: Substitute the workpiece motion parameters of the grinding wheel and the abrasive geometric parameters into the trajectory equation to obtain the trajectory scatter point coordinate matrix of the mapping relationship between the region where any abrasive grain is located on the surface of the mixed-size grinding wheel and the workpiece surface.

[0091] Establish a region on the surface of a grinding wheel with mixed particle size With any area of ​​the workpiece surface Given the mapping relationship, the coordinate matrix of the trajectory scatter points can be expressed by the following formula:

[0092] ;

[0093] in, Represents the surface area of ​​the workpiece The trajectory scatter point coordinate matrix, This indicates that the origin of the local coordinate system and the origin of the global coordinate system of the corresponding abrasive grain are at... The offset distance in the direction is the difference between the average tip height of the two abrasive grains on the grinding wheel surface and the grinding depth. This indicates the distance from the local coordinate origin to the global coordinate system origin of the trajectory of any cutting point on the grinding wheel. Distance along the axial direction.

[0094] After mapping the coordinate matrix of the trajectory scatter points and retaining the coordinates of the lowest point, it can be represented as:

[0095] ;

[0096] in, This represents the analysis domain coordinate matrix that stores the coordinates of the lowest point.

[0097] Step 3: Repeat steps 1 to 2 to map the coordinate matrix of the scatter points corresponding to the abrasive grains on the surface of all mixed-size grinding wheels, and obtain the workpiece surface roughness based on the lowest value of all coordinates.

[0098] The lowest coordinate values ​​corresponding to all abrasive grains are constructed and saved to the analysis domain coordinate matrix. Based on the analysis domain coordinate matrix, the workpiece surface morphology data is generated. The workpiece surface roughness is obtained from the workpiece surface morphology data and is calculated using the following formula:

[0099] ;

[0100] In other embodiments, the mixed-size grinding wheel can also be evaluated based on the lowest values ​​of all coordinates, including the peak value of the workpiece surface protrusion, the peak value of the workpiece groove width, and the root mean square value of the height difference.

[0101] Specifically, when the peak value of the protrusion on the workpiece surface exceeds the corresponding preset threshold, it indicates that the distribution of abrasive grains on the grinding wheel surface is too discrete, resulting in uneven removal of workpiece material. The number of fine abrasive grains should be increased or the size of coarse abrasive grains should be reduced to improve the grinding wheel's ability to refine the workpiece surface.

[0102] When the peak value of the workpiece groove width exceeds the preset average value of the workpiece surface contour, it indicates that the edge height of the abrasive grain is too low, which leads to an increase in the size of the residual groove formed by grinding. The edge height of the abrasive grain should be appropriately increased to reduce the width of the workpiece surface groove.

[0103] When the root mean square value of the height difference is greater than the preset value, it indicates that the workpiece surface shows large-scale grinding marks locally. The worse the contour uniformity, the more appropriate the cutting edge height of the abrasive should be to improve the contour flatness of the workpiece surface and improve the material removal efficiency.

[0104] Step 4: Compare the workpiece surface roughness with the preset roughness, and adjust the abrasive geometry parameters based on the comparison results until the obtained workpiece surface roughness is less than the preset roughness.

[0105] Specifically, the particle size ratio of coarse abrasive grains to fine abrasive grains is adjusted based on the comparison between the surface roughness and the preset roughness until the obtained workpiece surface roughness is less than the preset roughness.

[0106] When performing step 4, the theoretical removal volume of the workpiece surface is calculated based on the lowest value of all saved coordinates, and the material removal efficiency is calculated by comparing it with the simulated residual volume of the workpiece. The distribution density ratio of coarse abrasive grains to fine abrasive grains is adjusted according to the material removal efficiency until the material removal efficiency reaches the preset material removal value.

[0107] The volume removed from the workpiece in a single feed is expressed by the following formula:

[0108] ;

[0109] in, This indicates the volume of workpiece removed in a single feed. and This represents the distribution function of the two types of abrasive grains on the surface of a mixed-size grinding wheel. This represents the overlap coefficient of abrasive particles of mixed sizes within a cross-section. This represents the unit area of ​​the surface of a grinding wheel with mixed particle sizes.

[0110] Multiple sets of parameters were selected to predict the grinding results of mixed-size grinding wheels, providing a basis for the optimization of the mixed-size abrasive ratio, abrasive density ratio and other mixed-size abrasive proportion coefficients and the control of surface quality. The specific process parameter group settings are shown in Table 1.

[0111] Table 1: Grinding parameters for different abrasive grain sizes

[0112]

[0113] A suitable particle size ratio among mixed-size abrasive grains ensures that sufficient mixed abrasive grains can cross-participate in the grinding process per unit area. To ensure that the simulation conditions are highly consistent with actual grinding processes, the theoretical grinding depth is set to 20 μm, the grinding wheel linear velocity to 30 m / s, and the workpiece feed rate to 8 mm / s, so as to provide a basis for optimizing the design parameters of the mixed-size grinding wheel.

[0114] See Figure 2-5 Under different abrasive grain size ratios (0.4, 0.56, 0.67, 0.8) and different abrasive grain density ratios (0.5, 1, 1.5, 2), and combined with other conditions in Table 1, grinding simulations were conducted to obtain the workpiece surface morphology. This shows that when performing reciprocating grinding with a mixed-grain-size grinding wheel under specific feed parameters, the workpiece surface morphology can reflect the rationality of the abrasive grain size ratio.

[0115] (1) When the workpiece surface exhibits large-scale protrusions and grooves with non-uniform distribution, it indicates that the particle size ratio of the current mixed abrasive particles is insufficient to meet the processing requirements. This phenomenon is due to insufficient participation of fine abrasive particles, resulting in uneven material removal. At this time, the particle size ratio should be appropriately increased or the density ratio should be decreased to enhance the refining effect of fine abrasive particles on the grinding marks on the workpiece surface.

[0116] (2) If the workpiece surface exhibits a uniform and dense grinding texture, but the cumulative material removal is significantly lower than the theoretical volume to be removed, it indicates that the proportion of coarse abrasive grains is too low. In this case, although the surface quality is good, the material removal efficiency is insufficient. At this time, the particle size ratio should be appropriately reduced or the density ratio should be increased to achieve a balance between processing efficiency and surface quality.

[0117] Compare the grinding simulation results with the above particle size ratio and density ratio with the actual results, please refer to Tables 2 and 3;

[0118] Table 2: Simulation results of grinding with mixed-particle-size grinding wheels

[0119]

[0120] Table 3: Actual grinding results of mixed-grit grinding wheels

[0121]

[0122] Note: The peak value of the protrusion in the table is the peak value of the protrusion on the workpiece surface, and the peak value of the width in the table is the peak value of the groove width of the workpiece.

[0123] As can be seen from the above, the trends of the two are completely consistent. The maximum relative error of surface roughness is 24.22%, and the minimum relative error is 0.53%. The maximum relative error of the peak value of the workpiece surface protrusion is 56%, and the minimum relative error is 37.83%. The maximum relative error of the peak value of the workpiece groove width is 50%, and the minimum relative error is 42.5%. Therefore, the simulation method constructed in this invention has high accuracy in predicting the surface grinding results of the workpiece.

[0124] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes, characterized in that, Includes the following steps: Step 1: Set the workpiece motion parameters and abrasive geometric parameters, simulate the workpiece to be processed and the mixed-size grinding wheel composed of coarse and fine abrasive grains, and obtain the workpiece surface analysis domain. Based on the workpiece surface analysis domain, the workpiece motion parameters and abrasive geometric parameters, determine the trajectory equation of a certain abrasive grain on the surface of the mixed-size grinding wheel in the global coordinate system. When simulating a grinding wheel with a mixed particle size composed of coarse and fine abrasive grains, the following constraint applies: the center-to-center distance between any two abrasive grains is greater than the sum of the radii of the mixed abrasive grains, as expressed by the following formula: ； in, This represents the distance between the centers of any two abrasive grains; Indicates the abrasive grains in any two abrasive grains , Indicates the abrasive grains in any two abrasive grains , The value range is 1 to ; This indicates the average diameter of the coarse-grained abrasive grains. Indicates the average diameter of fine-grained abrasive grains; Step 2: Based on the trajectory equation described in Step 1, obtain the trajectory scatter coordinate matrix of the mapping relationship between the region where a certain abrasive grain is located on the surface of the mixed-size grinding wheel and the workpiece surface. Map the trajectory scatter coordinate matrix to the analysis domain of the workpiece surface and save the lowest coordinate value therein. Step 3: Repeat steps 1 to 2 to map the coordinate matrix of the scatter points corresponding to the abrasive grains on the surface of all mixed-size grinding wheels, and obtain the workpiece surface roughness based on the lowest value of all coordinates. Step 4: Compare the workpiece surface roughness with the preset roughness, and adjust the abrasive geometry parameters based on the comparison results until the obtained workpiece surface roughness is less than the preset roughness.

2. The simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes according to claim 1, characterized in that, When performing step 4, the theoretical removal volume of the workpiece surface is calculated based on the lowest value of all saved coordinates, and the material removal efficiency is calculated by comparing it with the simulated residual volume of the workpiece. The distribution density ratio of coarse abrasive grains to fine abrasive grains is adjusted according to the material removal efficiency until the material removal efficiency reaches the preset material removal value.

3. The simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes according to claim 1, characterized in that, When simulating a grinding wheel with a mixed particle size composed of coarse and fine abrasive grains, the shapes of the coarse and fine abrasive grains are set to random. The shapes include triangles, quadrilaterals, pentagons, and hexagons.

4. The simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes according to claim 1, characterized in that, When simulating a mixed-grain grinding wheel composed of coarse and fine abrasive grains, a threshold for the edge height is set to simulate the surface morphology of the grinding wheel after laser dressing, and the tips of the coarse and fine abrasive grains are cut off. The threshold value for the cutting edge height is set based on the plane of the grinding wheel bond and includes the following constraints: ； in, This indicates the set threshold for the blade extension height.

5. The simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes according to claim 1, characterized in that, The trajectory equation of a certain abrasive grain in the global coordinate system is obtained through the following steps: A local coordinate system is constructed based on the workpiece motion parameters of the grinding wheel and the geometric parameters of the abrasive grain. The trajectory equation corresponding to the abrasive grain is obtained based on the local coordinate system, and the trajectory equation in the global coordinate system is obtained based on the trajectory equation in the local coordinate system. The construction of the trajectory equation in the local coordinate system specifically includes: constructing the trajectory equation of any abrasive grain moving in a circular motion on the grinding wheel over time in the local coordinate system based on the workpiece motion parameters of the grinding wheel and the geometric parameters of the abrasive grain.

6. The simulation method for the surface morphology of CBN grinding wheel with mixed particle size according to claim 1, characterized in that, The trajectory scatter point coordinate matrix is ​​obtained by substituting the workpiece motion parameters and abrasive geometric parameters into the trajectory equation to obtain the trajectory scatter point coordinate matrix of the mapping relationship between the region where any abrasive grain is located on the surface of the mixed-size grinding wheel and the workpiece surface.

7. The simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes according to claim 1, characterized in that, The process of obtaining the workpiece surface roughness based on all the lowest coordinate values ​​includes: constructing and saving the lowest coordinate values ​​corresponding to all abrasive grains into the analysis domain coordinate matrix, forming workpiece surface morphology data based on the analysis domain coordinate matrix, and obtaining the workpiece surface roughness based on the workpiece surface morphology data.

8. The simulation method for the surface morphology of CBN grinding wheels with mixed particle sizes according to any one of claims 1-7, characterized in that, The grinding wheel workpiece motion parameters include grinding depth, grinding wheel linear speed, and workpiece feed speed; The abrasive geometric parameters include abrasive shape, abrasive particle size ratio, abrasive density ratio, and abrasive edge height.

9. The simulation method for the surface morphology of CBN grinding wheel with mixed particle size according to claim 8, characterized in that, Based on the lowest coordinate values ​​in step 3, the peak value of the workpiece surface protrusion, the peak value of the workpiece groove width, and the root mean square value of the height difference are calculated to evaluate the mixed-size grinding wheel. The peak value of the protrusion on the workpiece surface, the peak value of the workpiece groove width, and the root mean square value of the height difference are all evaluated based on preset thresholds. When the peak value of the protrusion on the workpiece surface exceeds the corresponding preset threshold, the abrasive particle size ratio or density ratio is adjusted. When the peak width of the workpiece groove exceeds the corresponding preset threshold, the abrasive grain protrusion height is adjusted. When the root mean square value of the height difference exceeds the corresponding preset threshold, the abrasive grain exit height is adjusted.

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