A tenon groove cutting performance prediction method considering broach regrinding defects

Abstract

The application discloses a tenon and groove cutting performance prediction method considering broach grinding defects. The method is as follows: S1, a cutting simulation model considering tool machining defects is constructed, and a contrast simulation model is constructed. S2, the simulation parameters of the contrast simulation model and the cutting simulation model considering tool machining defects are set. S3, the cutting simulation model considering tool machining defects is submitted for simulation solution, and simulation results under the condition that the tool surface has defects are obtained. S4, the contrast simulation model is submitted for simulation solution, and simulation results under the condition that the tool surface has no defects are obtained. S5, the simulation results of the contrast simulation model and the cutting simulation model considering tool machining defects are compared, and the influence of the machining defects on the tool on the tenon and groove cutting performance is obtained. The application can obtain the influence of the micro defects generated in the tool forming process on the tool service, so as to realize the prediction of the tenon and groove machining process.

Description

Technical Field

[0001] This invention belongs to the technical field of tool forming and service, and specifically relates to a method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects. Background Technology

[0002] Precision and complex cutting tools are widely used in various production environments, including the automotive, home appliance, military, and civilian industries. However, some applications demand high cutting performance from these tools, necessitating an evaluation of their tenon and grooving cutting performance. Although precision and complex cutting tools undergo precision pressing, sintering, precision grinding, and precision treatment of the forming tooth edges during the manufacturing process, micro-defects such as pits and scratches can still occur during tool regrinding. Currently, the distribution and size of these micro-defects are difficult to predict. Furthermore, the surface quality of the workpiece and the service life of the tool are difficult to predict during finishing processes, making it challenging to predict the cutting performance of the tool during tenon and grooving. Therefore, a simulation scheme is needed to predict the impact of tool regrinding on tenon and grooving cutting performance. Cutting simulation can compensate for factors such as tool surface stress and cutting temperature that cannot be reflected in cutting experiments. Combined with finite element analysis of tool structural strength, it allows for a deeper study of the effects of cutting parameters on cutting force, cutting temperature, and residual stress, while also elucidating the formation mechanism of chips and residual stress. Summary of the Invention

[0003] The purpose of this invention is to address the problems of unpredictable distribution and size of micro-defects such as pits and scratches generated in the current precision and complex tool forming process, and the difficulty in predicting the impact of these micro-defects on workpiece surface quality and tool service during finishing processes. This invention provides a method for predicting the cutting performance of tenons and grooves by considering broach grinding defects. This invention is a method that considers the forming mechanism of micro-defects in precision and complex tools and uses tools with micro-defects for finishing to improve simulation accuracy; it is a method that first performs grinding simulation of precision and complex tools, and then performs cutting simulation; it is a method that generates micro-defects such as pits and scratches through grinding simulation, and then performs cutting simulation on precision and complex tools with micro-defects to explore the impact of micro-defects generated in the tool forming process on tool service; it is a multi-scale simulation method that combines micro-scale micro-defects such as pits and grinding marks generated in grinding with macro-scale parameters such as cutting force and cutting heat in cutting simulation; it is a step-by-step simulation method for precision and complex tools from manufacturing to service.

[0004] This invention provides a method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects. The specific steps are as follows:

[0005] Step S1: Construct a cutting simulation model considering tool machining defects and a control simulation model. The cutting simulation model considering tool machining defects includes an unformed tool model (1), a grinding wheel assembly, and a workpiece model (4). The unformed tool model (1) has unformed areas. The grinding wheel assembly is used to perform grinding simulation on the unformed areas of the unformed tool model (1), so that cutting edges, rake faces, and flank faces are formed in the unformed areas of the unformed tool model (1). The control simulation model includes a general formed tool model (5) and a workpiece model (4).

[0006] Step S2: Set the simulation parameters for the comparison simulation model and the cutting simulation model that considers tool machining defects.

[0007] Step S3: Submit the cutting simulation model that considers tool machining defects to the simulation solution to obtain the simulation results under the condition that there are defects on the tool surface. The simulation process includes the tool grinding simulation stage and the cutting machining simulation stage.

[0008] S3-1. Tool grinding simulation stage.

[0009] The grinding wheel assembly performs grinding simulation on the unformed area of ​​the unformed tool model (1), so that the unformed tool model (1) is transformed into a tool with machining defects.

[0010] S3-2. Cutting process simulation stage.

[0011] The workpiece model (4) was subjected to cutting simulation using a tool with machining defects obtained from the tool grinding simulation stage, and the simulation results were obtained. The simulation results include the cutting force, stress, strain and temperature of the tool in the cutting simulation stage.

[0012] S4. Submit the comparison simulation model to the simulation solution to obtain the simulation results under the condition that the tool surface is free of defects.

[0013] S5. Compare the simulation results of the control simulation model with the cutting simulation model that considers tool machining defects to obtain the influence of machining defects on the tenon and groove cutting performance.

[0014] Preferably, the unformed area on the unformed tool model (1) is cuboid in shape. In the initial state, the unformed area is located on the side of the unformed tool model (1) closest to the workpiece model (4).

[0015] Preferably, the grinding wheel assembly includes a first grinding element (2) and a second grinding element (3). Both the first grinding element (2) and the second grinding element (3) are provided with grinding surfaces for simulating the grinding process of the unformed tool model (1). The grinding surfaces of the first grinding element (2) and the second grinding element (3) form a preset angle.

[0016] Preferably, both the first grinding component (2) and the second grinding component (3) are capable of moving toward the unformed tool model (1). The moving directions of the first grinding component (2) and the second grinding component (3) during the grinding simulation of the unformed tool model (1) are parallel to their own grinding surfaces.

[0017] As a preferred option, during the tool grinding simulation stage, the first grinding part (2) and the second grinding part (3) move toward the unformed tool model (1) one after another, grinding away part of the material on the unformed area of ​​the unformed tool model (1), so that the cutting edge, the rake face and the flank face are formed on the unformed area of ​​the unformed tool model (1).

[0018] Preferably, in step S1, in the cutting simulation model that considers tool machining defects, the contact area between the first grinding part (2) and the second grinding part (3) and the unformed tool model (1), the area being cut on the workpiece model (4) and its surrounding area are made of precision mesh; the remaining areas on the first grinding part (2), the second grinding part (3), the unformed tool model (1) and the workpiece model (4) are made of coarse mesh.

[0019] Preferably, in step S1, in the comparison simulation model, the contact area between the general forming tool model (5) and the workpiece model (4) and its surrounding area are made of precision mesh; the remaining areas on the general forming tool model (5) and the workpiece model (4) are made of coarse mesh.

[0020] As a preferred option, the parameters of the cutting simulation model that considers tool machining defects set in step S2 include material properties, analysis steps and output variables, contact constraints between the grinding wheel assembly and the unformed tool model (1), between the unformed tool model (1) and the workpiece model (4), motion characteristics and loads of the grinding wheel assembly and the unformed tool model (1).

[0021] As a preferred embodiment, in the tool grinding simulation stage, the cutting simulation model considering tool machining defects applies fully constrained boundary conditions to the sides of the unformed tool model (1) and the workpiece model (4). In the cutting simulation stage, the bottom surface of the workpiece model (4) is subject to completely fixed constraints.

[0022] As a preferred option, the cutting simulation model that considers tool machining defects adopts explicit dynamic analysis steps in both the tool grinding simulation stage and the cutting simulation stage.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. This invention constructs a model with an unformed cutting tool and uses a grinding wheel assembly to perform grinding simulation on the unformed cutting tool during the simulation process. This causes the front and rear cutting faces of the unformed cutting tool to automatically form small defects such as pits and scratches caused by grinding. This makes the simulation process more consistent with the actual processing situation of the tool with small defects caused by grinding, thereby improving the accuracy of the simulation results and realizing precise simulation testing of tenon and groove processing.

[0025] 2. This invention simulates the cutting results with machining defects on the tool surface and the simulation results without defects on the tool surface, and compares the two sets of simulation results to obtain the influence of the minute defects generated by the tool forming process on the tool's service life, so as to facilitate the prediction of the mortise and tenon machining process.

[0026] 3. In grinding simulation, this invention focuses only on the grinding plane, simplifies the overall structure of the grinding wheel assembly, and sets the grinding wheel assembly as a rigid body, thereby simplifying the simulation process and improving simulation efficiency. Attached Figure Description

[0027] Figure 1 This is a flowchart of the present invention;

[0028] Figure 2 This is a schematic diagram of the cutting simulation model that takes into account tool machining defects in this invention;

[0029] Figure 3 This is a schematic diagram of the comparative simulation model in this invention;

[0030] Figure 4 This is the overall mesh diagram of the cutting simulation model that considers tool machining defects in this invention.

[0031] Figure 5 This is the overall mesh diagram of the comparison simulation model in this invention;

[0032] Reference numerals: 1-Unformed tool model; 2-First grinding part; 3-Second grinding part; 4-Workpiece model; 5-General formed tool model. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0034] like Figure 1As shown, a method for predicting the cutting performance of tenons and grooves considering broaching and re-grinding defects is described, with the following specific steps:

[0035] Step S1: Construct a cutting simulation model that considers tool machining defects, and a comparison simulation model.

[0036] like Figure 2 and 4 As shown, the cutting simulation model considering tool machining defects includes an unformed tool model 1, a grinding wheel assembly, and a workpiece model 4. The grinding wheel assembly includes a first grinding part 2 and a second grinding part 3. The unformed tool model 1 has an unformed region in the shape of a cuboid. In the initial state, the unformed region is located on the side of the unformed tool model 1 closest to the workpiece model 4.

[0037] Both the first grinding component 2 and the second grinding component 3 are provided with grinding surfaces for simulating the grinding process of the unformed tool model 1. The grinding surfaces of the first grinding component 2 and the second grinding component 3 form a preset angle θ. Both the first grinding component 2 and the second grinding component 3 can move towards the unformed tool model 1 to simulate the grinding process of the unformed area of ​​the unformed tool model 1, thereby forming a cutting edge, a rake face, and a flank face in the unformed area of ​​the unformed tool model 1. The movement direction of the first grinding component 2 and the second grinding component 3 during the grinding process simulation of the unformed tool model 1 is parallel to their respective grinding surfaces.

[0038] The function of the grinding wheel assembly is to transform the unformed tool model 1 into a formed tool through simulation. The formed tool formed in this way will have minor defects on both the rake face and the flank face.

[0039] Therefore, the grinding simulation process between the grinding wheel assembly and the unformed tool model 1 in this embodiment mainly focuses on the grinding action between the grinding surfaces on the first grinding part 2 and the second grinding part 3 in the grinding wheel assembly and the unformed area on the unformed tool model 1, and does not focus on the shape of the grinding parts. Therefore, this embodiment adopts the grinding action of planar features to simplify this process, specifically using a cuboid with simple planar features for grinding simulation, so as to reduce unnecessary feature influence and unnecessary workload in the simulation process.

[0040] Considering the performance of precision and complex cutting tools, the materials of the first grinding part 2, the second grinding part 3, and the unformed tool model 1 are set to T15 powder metallurgy high-speed steel. In this embodiment, the material parameters of the first grinding part 2, the second grinding part 3, and the unformed tool model 1 are shown in Table 1; the material parameters of the workpiece model 4 are shown in Table 2.

[0041] Table 1 Material parameters for cutting tools and grinding wheels

[0042]

[0043] Table 2. Parameters of the base material of workpiece model 4

[0044]

[0045] like Figure 3 and 5 As shown, the comparative simulation model includes a general forming tool model 5 and a workpiece model 4. Except for its shape, the parameters of the general forming tool model 5 in the comparative simulation model are identical to those of the unformed tool model 1 in the cutting simulation model considering tool machining defects. The shape of the general forming tool model 5 is identical to the shape of the unformed tool model 1 after grinding by the grinding wheel assembly. The parameters in the workpiece model 4 in the comparative simulation model are identical to those in the cutting simulation model considering tool machining defects.

[0046] Mesh generation was performed on both the simulation model and the cutting simulation model that considered tool machining defects. In this embodiment, the contact areas between the first grinding part 2 and the second grinding part 3 and the unformed tool model 1, the area being cut on the workpiece model 4 and its surrounding area were given a precision mesh; the remaining areas on the first grinding part 2, the second grinding part 3, the unformed tool model 1 and the workpiece model 4 were given a coarse mesh.

[0047] In finite element simulation, mesh generation is a crucial step in the finite element model. The quantity and quality of the mesh directly affect the accuracy of the calculation results and the computational scale. Generally, a larger mesh increases computational accuracy, but also exponentially increases the number of degrees of freedom in the model, leading to longer computation time. When the mesh quantity is small, the mesh can be appropriately refined locally at stress concentration points, while the mesh can be sparser in stress-relaxed regions. This approach not only meets the accuracy requirements of the calculation results but also balances computational efficiency.

[0048] Step S2: Set the simulation parameters for the comparison simulation model and the cutting simulation model that considers tool machining defects.

[0049] The simulation process of the cutting simulation model is divided into the tool grinding simulation stage and the cutting simulation stage. The simulation parameters include the working parameter information, constraints, analysis step type, historical variable parameters, and field variable parameters of the grinding wheel assembly, unformed tool model 1, and workpiece model 4 in the tool grinding simulation stage and the cutting simulation stage.

[0050] The parameter information for workpiece model 4 includes its roughness, friction coefficient, material parameters, and motion characteristic parameters. The parameter information for the unformed tool model 1 includes its motion characteristics and load.

[0051] In the actual tool grinding process, the tool being ground is held on the machine tool by a fixture; therefore, in the tool grinding simulation stage of this embodiment, the side surface of the unformed tool model 1 and the bottom surface of the workpiece model 4 are regarded as completely fixed, and fully constrained boundary conditions are applied to the side surface of the unformed tool model 1 and the workpiece model 4.

[0052] In the actual cutting process, the workpiece model 4 is fixed to the machine tool by a fixture. Therefore, in this embodiment, the bottom surface of the workpiece model 4 is subjected to a completely fixed constraint during the cutting simulation stage.

[0053] In this embodiment, based on the characteristics of the grinding motion, the analysis step type is selected as the display dynamic analysis step.

[0054] Historical variable parameters in the tool grinding simulation stage include grinding force during the grinding process; historical variable parameters in the cutting simulation stage include cutting force during the cutting process.

[0055] The field variable parameters in both the tool grinding simulation stage and the cutting simulation stage include displacement, velocity, acceleration, stress, and strain.

[0056] The parameters of the simulation model during the simulation process (specifically, the material properties, constraints, analysis step type, historical variable parameters, and field variable parameters of the general forming tool model 5 and the workpiece model 4) are consistent with the cutting simulation stage of the cutting simulation model that considers tool machining defects.

[0057] Step S3: Import the cutting simulation model considering tool machining defects established in steps S1 and S2 into the finite element simulation software, submit the solution, complete the cutting simulation, and obtain the simulation results under the condition that there are defects on the tool surface. The specific process of cutting simulation includes the tool grinding simulation stage and the cutting simulation stage.

[0058] S3-1. Tool grinding simulation stage.

[0059] The first grinding part 2 and the second grinding part 3 move sequentially towards the unformed tool model 1, grinding away some material from the unformed area of ​​the unformed tool model 1, thus forming a cutting edge, a rake face, and a flank face on the unformed area of ​​the unformed tool model 1, transforming the unformed tool model 1 into a tool with machining defects. In the tool grinding simulation stage, the first grinding part 2 and the second grinding part 3 are defined as rigid bodies; the unformed tool model 1 is defined as a flexible body.

[0060] S3-2. Cutting process simulation stage.

[0061] The workpiece model 4 was subjected to cutting simulation using a tool with machining defects obtained during the tool grinding simulation stage. The cutting simulation results were obtained. In the cutting simulation stage, the tool with machining defects was defined as a rigid body. Furthermore, the cutting edge should be lower than the upper surface of workpiece model 4 to ensure the mortise and tenon cutting. The simulation results include the tool cutting force, stress, strain, and temperature during the cutting simulation stage. If the simulation results do not converge, the parameters of the cutting simulation model considering the tool machining defects are readjusted and the simulation is resubmitted.

[0062] S4. Import the control simulation model into the finite element simulation software and submit the solution to complete the cutting simulation and obtain the simulation results under the condition that the tool surface is free of defects. The simulation results obtained in this step are used as a control group.

[0063] S5. Compare and analyze the simulation results of the control simulation model and the cutting simulation model that considers tool machining defects; specifically, compare the cutting force, cutting temperature, and surface residual stress values ​​obtained from the two simulation models to obtain the influence of small defects on the front and rear faces of the tool on the tenon and groove cutting performance.

[0064] S6. Adjust the simulation parameters multiple times and execute steps S3 to S5, and analyze the impact of minor defects on the front and rear faces of the tool on the tenon and groove cutting performance under different machining conditions.

[0065] In this embodiment, a cutting simulation model considering tool machining defects is used, and the JC material constitutive model is used to describe the stress-strain relationship of workpiece model 4 (GH4169 steel) in comparison with the simulation model.

[0066] The JC constitutive model and damage model are shown below:

[0067]

[0068]

[0069] Where, σ JC The uniaxial tensile thermoviscoelastic-plastic rheological stress of the material is obtained from the traditional thermoviscoelastic-plastic JC constitutive equation; ε is the strain. For strain rate; T is the reference strain rate; T0 is the reference temperature; T melt Let be the melting temperature of the material; A, B, C, n, and m are all constants. Dimensionless plastic strain rate; T * =(TT) r ) / (T m -T) Dimensionless temperature; Indicates stress triaxiality, where σ m For spherical stress, This is the Mises equivalent stress.

[0070] Its JC constitutive parameters and JC damage parameters are shown in Tables 3 and 4:

[0071] Table 3 JC constitutive model parameters for GH4169 steel

[0072]

[0073] Table 4 JC damage model parameters for GH4169 steel

[0074]

[0075] As described above, it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention, and such other forms should not be construed as limiting the invention itself. Various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for predicting the cutting performance of tenons and grooves considering broaching and regrinding defects, characterized in that: Includes the following steps: Step S1: Construct a cutting simulation model that considers tool machining defects and a control simulation model; The cutting simulation model that considers tool machining defects includes an unformed tool model (1), a grinding wheel assembly and a workpiece model (4); The unformed tool model (1) has an unformed area; The grinding wheel assembly is used to perform grinding simulation on the unformed area on the unformed tool model (1), so that a cutting edge, a rake face and a flank face are formed in the unformed area of ​​the unformed tool model (1); The control simulation model includes a general formed tool model (5) and a workpiece model (4); Step S2: Set the simulation parameters for the control simulation model and the cutting simulation model that considers tool machining defects; Step S3: Submit the cutting simulation model that considers tool machining defects to the simulation solution to obtain the simulation results under the condition that there are defects on the tool surface; the simulation process includes the tool grinding simulation stage and the cutting simulation stage; S3-1. Tool grinding simulation stage; The grinding wheel assembly performs grinding simulation on the unformed area of ​​the unformed tool model (1), so that the unformed tool model (1) is transformed into a tool with machining defects; S3-2. Cutting process simulation stage; Using a tool with machining defects obtained from the tool grinding simulation stage, the workpiece model (4) is subjected to cutting simulation to obtain simulation results; the simulation results include the cutting force, stress, strain and temperature of the tool in the cutting simulation stage; S4. Submit the comparison simulation model to the simulation solution to obtain the simulation results under the condition that the tool surface is free of defects; S5. Compare the simulation results of the control simulation model with the cutting simulation model that considers tool machining defects to obtain the influence of machining defects on the tenon and groove cutting performance.

2. The method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects according to claim 1, characterized in that: The unformed area on the unformed tool model (1) is rectangular; in the initial state, the unformed area is located on the side of the unformed tool model (1) close to the workpiece model (4).

3. The method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects according to claim 1, characterized in that: The grinding wheel assembly includes a first grinding component (2) and a second grinding component (3); both the first grinding component (2) and the second grinding component (3) are provided with grinding surfaces for simulating grinding of the unformed tool model (1); the grinding surfaces of the first grinding component (2) and the second grinding component (3) form a preset angle.

4. The method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects according to claim 3, characterized in that: The first grinding component (2) and the second grinding component (3) can both move toward the unformed tool model (1); the first grinding component (2) and the second grinding component (3) move in the same direction as their own grinding surfaces when simulating grinding of the unformed tool model (1).

5. The method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects according to claim 3, characterized in that: In the tool grinding simulation stage, the first grinding part (2) and the second grinding part (3) move toward the unformed tool model (1) one after another, grinding away part of the material on the unformed area of ​​the unformed tool model (1), so that the cutting edge, the rake face and the flank face are formed on the unformed area of ​​the unformed tool model (1).

6. The method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects according to claim 3, characterized in that: In step S1, in the cutting simulation model that considers the defects of tool processing, the contact area between the first grinding part (2) and the second grinding part (3) and the unformed tool model (1), the area being cut on the workpiece model (4) and its surrounding area are made of precision mesh; the remaining areas on the first grinding part (2), the second grinding part (3), the unformed tool model (1) and the workpiece model (4) are made of coarse mesh.

7. The method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects according to claim 1, characterized in that: In step S1, in the comparison simulation model, the contact area between the general forming tool model (5) and the workpiece model (4) and its surrounding area are made of precision mesh; the remaining areas on the general forming tool model (5) and the workpiece model (4) are made of coarse mesh.

8. The method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects according to claim 1, characterized in that: The parameters of the cutting simulation model that considers tool machining defects set in step S2 include material properties, analysis steps and output variables, contact constraints between the grinding wheel assembly and the unformed tool model (1), between the unformed tool model (1) and the workpiece model (4), motion characteristics and loads of the grinding wheel assembly and the unformed tool model (1).

9. The method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects according to claim 1, characterized in that: In the tool grinding simulation stage, the cutting simulation model considering tool machining defects applies fully constrained boundary conditions to the side surface of the unformed tool model (1) and the workpiece model (4); in the cutting simulation stage, the cutting simulation model considering tool machining defects applies completely fixed constraints to the bottom surface of the workpiece model (4).

10. The method for predicting the cutting performance of tenons and grooves considering broaching and grinding defects according to claim 1, characterized in that: The cutting simulation model that considers tool machining defects adopts explicit dynamic analysis steps in both the tool grinding simulation stage and the cutting simulation stage.

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