Micro-texture drilling tool and micro-texture structure design method

Abstract

The invention relates to the technical field of drilling tools, and discloses a micro-texture drilling tool, a micro-texture structure design method and a micro-texture drilling tool. The micro-texture drilling tool comprises a front tool face, a tool nose, a main cutting edge and a micro-texture structure, the micro-texture structure is arranged on the front tool face, and the micro-texture structure comprises a near-field design area and a plurality of micro-texture units; wherein the near-field design area extends in the direction of the main cutting edge, the contour of the near-field design area is determined by a wear area on the front cutter face, the plurality of micro-texture units are arranged in the near-field design area, each micro-texture unit extends in the flowing-out direction of cuttings, the flowing-out direction of the cuttings is determined by scratches of the cuttings on the front cutter face, and the micro-texture units are arranged in the near-field design area. Compared with a traditional micro-texture position design, the method has the advantages that the micro-texture placement area is determined more accurately, the scientific design concept is better met, the micro-texture units are arranged in the chip flowing-out direction, derivative cutting defects caused by the micro-texture units in the cutting process can be well avoided, and the cutting performance is improved.

Description

Technical Field

[0001] The invention relates to the technical field of drilling tools, in particular to a micro-texture drilling tool and a micro-texture structure design method. Background Art

[0002] Hole processing is an important part of mechanical processing, and drilling tools are indispensable tools in hole processing. Indexable insert drills are widely used due to a series of advantages such as stable processing process, high feed rate, and low material cost. The processing diameter of indexable inserts is higher than that of ordinary drills, which well meets the needs of large diameter drilling such as 50-60mm.

[0003] Existing drilling tools mainly include quadrilaterals, convex triangles, rhombuses, hexagons, etc., which are subjected to severe drilling thermal loads and torque during use, which can easily cause tool wear and even chipping, seriously affecting the service life of the tool. The insertion of micro-textures can, to a certain extent, enable the tool to improve the cutting lubrication performance, reduce the surface roughness of the workpiece and the generation of chips, thereby greatly improving the cutting efficiency, and has great development potential.

[0004] In the existing drilling tool setting process, the empirical method is mostly used to design micro-textures, and the micro-texture structure is simple, and the effect of improving the tool stress and high temperature conditions is not obvious. The micro-texture design process lacks a theoretical basis and cannot form a scientific tool design method. It can no longer meet the existing tool design needs. In response to the above problems, this application is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a micro-texture drilling tool and a micro-texture structure design method, so as to overcome the problem that the traditional simple structure micro-texture has no obvious effect on improving the tool stress and high temperature conditions, and to provide a scientific micro-texture structure design method, so that the micro-texture design conforms to the actual use of the tool and improves the tool cutting performance.

[0006] The present invention is achieved through the following technical solutions.

[0007] A micro-texture drilling tool of the present invention comprises a rake face, a tool tip, a main cutting edge and a micro-texture structure, wherein the two sides of the tool tip are respectively connected to the main cutting edge and the secondary cutting edge, a mounting hole is arranged in the middle of the tool, the micro-texture structure is arranged on the rake face, the micro-texture structure comprises a near-domain design area and a plurality of micro-texture units, wherein the near-domain design area is extended along the direction of the main cutting edge, the plurality of micro-texture units are arranged in the near-domain design area, and each micro-texture unit is extended along the chip outflow direction.

[0008] The drilling tool of this solution can be a triangular, quadrilateral, rhombus, hexagonal or other tool.

[0009] The wear area of ​​the tool rake face is first obtained, and the irregular elliptical near-domain design area is obtained by spline curve interpolation. The chip outflow direction is obtained by measuring the scratches of the chips on the rake face with a microscope.

[0010] Furthermore, the transverse cross-section of the micro-texture unit is rectangular, arc-shaped or triangular.

[0011] Furthermore, the longitudinal cross-section of the micro-texture unit is in an arc shape, and the depth of the middle portion is greater than that of the two ends, which helps the chips to flow out smoothly and avoids chip accumulation.

[0012] Furthermore, the near-domain design area is in an irregular elliptical shape.

[0013] Furthermore, the irregular elliptical boundary of the near-domain design area is obtained by measuring the wear area of ​​the rake face of the tool in the cutting experiment and drawing it with the help of spline curve interpolation.

[0014] Optionally, the width a of the micro-texture unit is 0.2-0.4 mm, the spacing b is 0.3-0.6 mm, the maximum depth h is 0.04-0.1 mm, and the minimum distance c between the near-domain design area and the main cutting edge is 0.08-0.18 mm.

[0015] Furthermore, the liquid storage tank is in the shape of a fan ring, and the large end is placed inside.

[0016] Optionally, the outline of the micro-texture unit is linear, elliptical or crescent-shaped.

[0017] A micro-texture structure design method is used to design the micro-texture structure in the above-mentioned tool, comprising the following steps:

[0018] S1: Determine the near-domain design area: obtain the wear area boundary of the tool rake face, and then obtain the irregular elliptical near-domain design area with the help of the wear area boundary contour;

[0019] S2: Designing micro-texture units: By using the scratches formed by the tool under the action of the chips, the direction of chip outflow is measured, and the micro-texture units are designed along the chip outflow direction, including the transverse cross-sectional shape, width a, spacing b, maximum depth h and minimum distance c of the micro-texture units;

[0020] S3: Obtain cutting simulation data: for the micro-texture unit designed in step S2, set up several groups of simulation experiments under different micro-texture unit cross-sectional shapes to obtain the cutting force, cutting temperature and machining torque corresponding to the corresponding structure;

[0021] S4: Establish a prediction model for micro-texture unit parameters: perform sample preprocessing on the simulation data obtained in step S3, randomly select a part as a training set and a part as a test set, and use the support vector regression method to obtain a machine learning model of cutting force, cutting temperature and machining torque under different parameters. The hyperparameters of the model are optimized using the Bayesian method, and the accuracy of the prediction model is evaluated by the root mean square error and the determination coefficient;

[0022] The formulas for calculating the root mean square error and the coefficient of determination are as follows:

[0023]

[0024] In the formula, y i is the true value, y p is the predicted value, m is the number of values, y a is the average of the true values;

[0025] S5: Optimize the structural parameters of the micro-texture unit: Take the structural parameters of the micro-texture unit as input, cutting force, cutting temperature and machining torque as output, establish the objective function and constraint conditions, carry out multi-objective optimization, and obtain the best combination of structural parameters. The expression of the multi-objective optimization problem is as follows:

[0026]

[0027] In the formula, x∈X, F(x)∈Y, x is the decision vector, X is the decision space, F(x) is the target vector, Y is the target space, and g i (x) is an inequality function constraint, h i (x) is an equality function constraint, g i (x) and h i (x) is used to determine the feasible region of the decision vector.

[0028] Beneficial effects of the present invention: In the micro-texture drilling tool of the present invention, the irregular boundary of the near-domain design area is obtained by measuring the wear area of ​​the front cutting edge of the tool in the cutting experiment and drawing it with the help of spline curve interpolation. Compared with the previous position design, the present invention more accurately determines the area where the micro-texture is placed, which is more in line with the scientific design concept. The micro-texture units are arranged along the chip outflow direction, and the chip outflow direction is obtained by measuring the scratches of the chips on the front cutting edge with a microscope. This can effectively avoid the derivative cutting disadvantages caused by the micro-texture units during the cutting process and improve the cutting performance.

[0029] A liquid reservoir is arranged on the inner side of the near-domain design area, and the liquid reservoir is connected with the micro-texture, which helps to store more cutting fluid in the liquid reservoir and penetrate into the contact area between the tool and the chips through the micro-texture to improve the lubrication efficiency. The present invention has a simple structure, good effect, and reliable use, and is suitable for the promotion and use of indexable insert drills.

[0030] The longitudinal cross-section of the micro-texture is arc-shaped, and the depth in the middle is greater than that at both ends, which helps the chips to flow out smoothly and avoids chip accumulation.

[0031] The design of microtexture is achieved by determining the near-domain design area, designing microtexture, obtaining cutting simulation data, establishing a prediction model for microtexture and parameters, and optimizing the structural parameters of microtexture. Combining the advantages of experiments and machine learning, the design is more accurate and feasible. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0034] Figure 1 It is a schematic diagram of the overall structure of the micro-texture drilling tool;

[0035] Figure 2 It is a schematic diagram of the local structure of the micro-texture structure;

[0036] Figure 3 It is an enlarged schematic diagram of the near-domain design area and micro-texture unit;

[0037] Figure 4 It is a schematic diagram of the structure in which the outline of the micro-texture unit is an ellipse;

[0038] Figure 5 It is a schematic diagram of the structure in which the micro-texture unit outline is crescent-shaped;

[0039] Figure 6 For Example 1 Figure 3 Schematic diagram of the structure at AA;

[0040] Figure 7 For Example 4 Figure 3 Schematic diagram of the structure at AA;

[0041] Figure 8 For Example 5 Figure 3 Schematic diagram of the structure at AA;

[0042] Fig. 9 for Figure 3 Schematic diagram of the structure at BB;

[0043] Fig. 9 for Figure 3Sectional view along line BB;

[0044] Fig.10 Flow chart of the process of establishing the micro-texture unit parameter prediction model;

[0045] 1-front cutting edge; 2-mounting hole; 3-secondary cutting edge; 4-tool tip; 5-microtexture unit; 6-near-domain design area; 7-main cutting edge; 8-liquid reservoir. DETAILED DESCRIPTION

[0046] Combine the following Figure 1-10 The present invention is described in detail.

[0047] Embodiment 1:

[0048] A micro-textured drilling tool according to the present invention, such as Figure 1 In this embodiment, the tool is a triangular tool, including a front cutting surface 1 and a cutting tip 4. The cutting tip 4 is arranged at the sharp corner of the front cutting surface 1, and the two sides of the cutting tip 4 are respectively connected to the main cutting edge 7 and the secondary cutting edge 3. A mounting hole 2 is arranged in the middle of the tool.

[0049] A micro-texture structure is arranged on the front cutting edge, and the micro-texture structure includes a near-domain design area 6, a micro-texture unit 5 and a liquid reservoir 8. Specifically, a near-domain design area 6 is arranged on the inner side of the tool tip 4, and the near-domain design area 6 is arranged along the direction of the main cutting edge 7. A plurality of micro-texture units 5 are arranged in the near-domain design area 6, and each micro-texture unit 5 is arranged along the chip outflow direction. The length of the micro-texture unit 5 varies with the width of the near-domain design area 6. A liquid reservoir 8 is arranged on the inner side of the near-domain design area 6, and the liquid reservoir 8 is connected to the micro-texture unit 5.

[0050] Alternatively, if Figure 3-Figure 5 The contour shape of the micro-texture unit 5 can be set to be linear, elliptical or crescent.

[0051] In this embodiment, the preferred type is linear, i.e. Figure 3 Medium shape.

[0052] Preferably, the liquid storage tank 8 is in the shape of a fan ring, with the large end placed inside.

[0053] When in use, a cutting experiment is first conducted on the drilling tool to obtain the wear area of ​​the tool rake face 1, and the irregular elliptical near-domain design area 6 is obtained by spline curve interpolation. At the same time, the scratches of the chips on the rake face 1 are measured with a microscope to obtain the chip outflow direction, that is, the arrangement direction of the micro-texture unit 5 is obtained, and then the micro-texture design is started.

[0054] In this embodiment, Figure 6 , wherein the transverse cross section ( Figure 3 The longitudinal section ( Figure 3The micro texture unit 5 has a width a of 0.2 mm, a spacing b of 0.3 mm, and a maximum depth h of 0.04 mm. Fig. 9 It can be seen that the depth in the middle is the largest, and the depth gradually decreases toward both sides. The minimum distance c between the near-domain design area 6 and the main cutting edge 7 is 0.08 mm.

[0055] It can be seen from the above technical solutions that in the micro-texture drilling tool of the present invention, the irregular elliptical boundary of the near-domain design area is obtained by measuring the wear area of ​​the front cutting edge of the tool in the cutting experiment and drawing it with the help of spline curve interpolation. Compared with the previous position design, the present invention more accurately determines the area where the micro-texture is placed, not just based on experience, and is more in line with scientific design concepts. The micro-texture units are arranged along the chip outflow direction, and the chip outflow direction is obtained by measuring the scratches of the chips on the front cutting edge with the help of a microscope. It can well avoid the derivative cutting disadvantages caused by the micro-texture units during the cutting process and improve the cutting performance. A liquid reservoir is provided on the inner side of the near-domain design area. The liquid reservoir is connected to the micro-texture. The liquid reservoir is in the shape of a fan ring, and the large end is placed on the inner side, which helps to store more cutting fluid in the liquid reservoir, and penetrate into the contact area between the tool and the chip through the micro-texture to improve the lubrication efficiency. The present invention has a simple structure, good effect, and reliable use, and is suitable for the promotion and use of indexable insert drills.

[0056] The longitudinal cross-section of the micro-texture is arc-shaped, and the depth in the middle is greater than that at both ends, which helps the chips to flow out smoothly and avoids chip accumulation.

[0057] Embodiment 2: Different from Embodiment 1, the width a of the micro-texture unit 5 is 0.3 mm, the spacing b is 0.45 mm, the maximum depth h is 0.07 mm, and the minimum distance c between the near-domain design area 6 and the main cutting edge 7 is 0.13 mm.

[0058] Embodiment 3: Different from Embodiment 1, the width a of the micro-texture unit 5 is 0.4 mm, the spacing b is 0.6 mm, the maximum depth h is 0.1 mm, and the minimum distance c between the near-domain design area 6 and the main cutting edge 7 is 0.18 mm.

[0059] Embodiment 4: Different from Embodiment 1, Figure 7 The transverse cross section of the micro-texture unit 5 is in the shape of an arc.

[0060] Embodiment 5: Different from Embodiment 1, Figure 8 The transverse cross section of the micro-texture unit 5 is triangular.

[0061] A micro-texture structure design method is used to set the micro-texture structure in any one of the above embodiments, and the design method comprises the following steps:

[0062] S1: Determine the near-domain design area 6: Carry out cutting experiments until the tool life is reached, obtain the wear area boundary of the tool rake face (1), and then use the spline curve to obtain the irregular elliptical near-domain design area (6);

[0063] S2: Designing micro-texture unit 5: obtaining the scratches formed by the tool under the action of chips through the experiment in step S1, measuring the direction of chip outflow with the help of a microscope, and designing micro-texture unit 5 along the direction of chip outflow, including the transverse cross-sectional shape, width a, spacing b, maximum depth h and minimum distance c of the micro-texture unit 5;

[0064] S3: Obtain cutting simulation data: for the micro-texture unit 5 designed in step S2, multiple groups of simulation experiments at 3-5 levels are set under different cross-sectional shapes of the micro-texture unit 5 to obtain the cutting force, cutting temperature and machining torque corresponding to the corresponding structure;

[0065] S4: Establish a prediction model for the parameters of micro-texture unit 5: The simulation data obtained in step S3 are preprocessed, 2 / 3 are randomly selected as the training set and 1 / 3 as the test set, and the machine learning model of cutting force, cutting temperature and machining torque under different parameters is obtained by support vector regression method. The hyperparameters of the model are optimized by Bayesian method, and the root mean square error (RMSE) and determination coefficient (R 2 ) evaluates the accuracy of the prediction model, where the modeling process of the support vector regression method is as follows Fig.10 As shown;

[0066] RMSE and R 2 The calculation formula is as follows:

[0067]

[0068] In the formula, y i is the true value, y p is the predicted value, m is the number of values, y a It is the average value of the true value. RMSE indicates the deviation between the predicted value and the true value, reflecting the accuracy of the prediction effect. The smaller the value, the more accurate the prediction. 2 It indicates the degree to which the independent variable can explain the dependent variable. Its size determines the degree of correlation. Its value ranges from 0 to 1. The closer it is to 1, the more accurate the prediction result.

[0069] Using RMSE and R 2 The formula realizes the optimal judgment of the model and obtains the best hyperparameters.

[0070] R 2The closer it is to 1, the more accurate the result and the better the model. The smaller the RMSE value, the more accurate the prediction. However, there is no definite value and it needs to be explained through result comparison (for example, 10 is smaller than 100, but larger than 1).

[0071] The training set is used for model training, providing input features and targets so that the model can learn the mapping relationship between features and targets. The test set is used to evaluate the final performance of the model, and the test set must be data that has not been used in the model training process.

[0072] S5: After the best prediction model is formed in step S4, the parameters used for this step are optimized to optimize the structural parameters of the micro-texture unit 5: the structural parameters of the micro-texture unit 5 are used as input, the cutting force, cutting temperature and machining torque are used as output, the objective function and constraint conditions are established, and multi-objective optimization is carried out to obtain the best structural parameter combination, wherein the multi-objective optimization problem is expressed as follows:

[0073]

[0074] In the formula, x∈X, F(x)∈Y, x is the decision vector, X is the decision space, F(x) is the target vector, Y is the target space, and g i (x) is an inequality function constraint, h i (x) is an equality function constraint, g i (x) and h i (x) is used to determine the feasible domain of the decision vector. F(x) contains three components, namely, f1(x), f2(x), and f3(x), which represent the cutting force, cutting temperature, and machining torque, respectively.

[0075] The design of microtexture is achieved by determining the near-domain design area, designing microtexture, obtaining cutting simulation data, establishing a prediction model for microtexture and parameters, and optimizing the structural parameters of microtexture. Combining the advantages of experiments and machine learning, the design is more accurate and feasible.

[0076] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology in this field to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A micro-textured drilling tool, characterized in that: The invention comprises a front cutting face (1), a cutting edge (4), a main cutting edge (7) and a micro-texture structure, wherein the micro-texture structure is arranged on the front cutting face (1), and the micro-texture structure comprises a near-domain design area (6) and a plurality of micro-texture units (5), wherein the near-domain design area (6) is extended along the direction of the main cutting edge (7), and the contour of the near-domain design area (6) is determined by the wear area on the front cutting face (1), and the plurality of micro-texture units (5) are arranged in the near-domain design area (6), and each micro-texture unit (5) is extended along the chip outflow direction, and the chip outflow direction is determined by the scratches of the chips on the front cutting face (1).

2. The micro-textured drilling tool according to claim 1, characterized in that: The micro-textured structure further comprises a liquid storage tank (8), wherein the liquid storage tank (8) is arranged inside the near-domain design area (6), and the liquid storage tank (8) is connected to the micro-textured unit (5).

3. The micro-textured drilling tool according to claim 1 or 2, characterized in that: The transverse cross section of the micro-texture unit (5) is rectangular, arc-shaped or triangular.

4. The micro-textured drilling tool according to claim 3, characterized in that: The longitudinal cross-section of the micro-texture unit (5) is in the shape of an arc, and its width gradually decreases from the middle to both ends.

5. The micro-textured drilling tool according to claim 4, characterized in that: The width of the micro-texture unit (5) is 0.2-0.4 mm, the maximum depth is 0.04-0.1 mm, and the spacing between adjacent micro-texture units (5) is 0.3-0.6 mm.

6. The micro-textured drilling tool according to claim 5, characterized in that: The minimum distance between the near-domain design area (6) and the main cutting edge (7) is 0.08-0.18 mm.

7. The micro-textured drilling tool according to claim 1 or 2, characterized in that: The outline of the micro-texture unit (5) is linear, elliptical or crescent-shaped.

8. The micro-textured drilling tool according to claim 2, characterized in that: The liquid storage tank (8) is in the shape of a fan ring, with its large end placed inside.

9. The micro-textured drilling tool according to claim 1, characterized in that: The number of the micro-texture structures is the same as the number of the knife tips (4).

10. A method for designing a micro-texture structure, used for designing a micro-texture structure in a tool according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: Determine the near-domain design area (6): Obtain the wear area boundary of the tool rake face (1), and then obtain the irregular elliptical near-domain design area (6) with the help of the wear area boundary contour; S2: Designing a micro-texture unit (5): by using scratches formed by the tool under the action of the chips, measuring the direction of chip outflow, and designing the micro-texture unit (5) along the chip outflow direction, including the transverse cross-sectional shape, width a, spacing b, maximum depth h and minimum distance c of the micro-texture unit (5); S3: Obtain cutting simulation data: for the micro-texture unit (5) designed in step S2, set up several groups of simulation experiments under different cross-sectional shapes of the micro-texture unit (5) to obtain the cutting force, cutting temperature and machining torque corresponding to the corresponding structure; S4: Establishing a prediction model for the parameters of the micro-texture unit (5): Preprocessing the simulation data obtained in step S3, randomly selecting a part as a training set and a part as a test set, and using the support vector regression method to obtain a machine learning model of cutting force, cutting temperature and machining torque under different parameters, optimizing the hyperparameters of the model using the Bayesian method, and evaluating the accuracy of the prediction model by the root mean square error and the determination coefficient; The formulas for calculating the root mean square error and the coefficient of determination are as follows: In the formula, y i is the true value, y p is the predicted value, m is the number of values, y a is the average of the true values; S5: Optimizing the structural parameters of the micro-texture unit (5): Taking the structural parameters of the micro-texture unit (5) as input, and taking the cutting force, cutting temperature and machining torque as output, an objective function and constraint conditions are established, and a multi-objective optimization is carried out to obtain the best structural parameter combination. The expression of the multi-objective optimization problem is as follows: In the formula, x∈X, F(x)∈Y, x is the decision vector, X is the decision space, F(x) is the target vector, Y is the target space, and g i (x) is an inequality function constraint, h i (x) is an equality function constraint, g i (x) and h i (x) is used to determine the feasible region of the decision vector.

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