Preparation method of diamond grinding wheel with micro-comb tooth structure with abrasive particle positive relief angle and obtained diamond grinding wheel

Abstract

The invention discloses a preparation method of a micro-comb-tooth structure diamond grinding wheel with abrasive particle positive relief angles and the obtained diamond grinding wheel, and the preparation method comprises the following steps: step 1, preparing grooves which are arranged in order to form a certain array on the circumferential surface of a grinding wheel base body through precision milling, and directionally bonding diamond abrasive particles in the grooves by using conductive adhesive; nickel-cobalt alloy is deposited through a pulse electroplating method to achieve mechanical solidification of the abrasive particles; 2, the grinding wheel obtained in the step 1 is shaped through a pulse laser system, and effective control over the outer circumference run-out of the grinding wheel is achieved; 3, the abrasive particle positive relief angle, obtained in the step 2, of the grinding wheel is subjected to forming machining; and 4, micro comb tooth structure machining is conducted on the grinding wheel in the step 3.

Description

Technical Field

[0001] The present invention relates to a method for laser processing and preparation of a micro-comb tooth structure diamond grinding wheel with a positive back angle of abrasive grains, belonging to the technical field of laser processing of structured grinding wheels. Background Art

[0002] Materials such as cemented carbide, glassy carbon, and fused quartz are widely used in high-precision industries such as optical systems, precision electronics, and medical machinery due to their excellent properties such as high hardness and high strength. However, their brittle characteristics also limit the application of precision and ultra-precision machining technologies such as single-point diamond turning and milling. Ultra-precision grinding is a machining method that can balance machining accuracy, surface quality, and machining efficiency in the ultra-precision machining of brittle materials. Its purpose is to produce parts with high surface finish, high shape accuracy, and high surface integrity. Traditional diamond grinding wheels are formed by pressing a mixture of abrasive grains and binder and then sintering and solidifying. The abrasive grains are randomly distributed on the working surface of the grinding wheel. The interference of abrasive grains and the low effective utilization rate of abrasive grains on the working surface of the grinding wheel affect the sharpness of the grinding wheel. Such grinding wheels are prone to grinding wheel clogging during the process of high-efficiency grinding and grinding of difficult-to-machine materials, resulting in an increase in grinding force and grinding temperature, and a decrease in grinding quality and grinding efficiency. By structuring the diamond grinding wheel, the regulation and control of the arrangement mode of abrasive grains, the concentration of abrasive grains, the axial and circumferential spacing of abrasive grains can be realized, thereby reducing the complexity and randomness of the grinding process and increasing the chip space. At the same time, the positive back angle of abrasive grains also has an important influence on the grinding performance of the grinding wheel. Abrasive grains with a positive back angle are conducive to achieving plastic removal of materials, while the scratching, squeezing, and plowing phenomena of abrasive grains with a negative back angle are likely to cause subsurface damage to the workpiece.

[0003] In the manufacturing process of structured grinding wheels, compared with traditional force-based mechanical dressing methods, laser-based methods avoid the direct influence of force or hard contact and have various significant advantages: wide applicability; small heat-affected area, high precision and efficiency; no wear loss, high precision and high flexibility. It has significant advantages in terms of processing range, manufacturing scale, material saving and environmental protection.

[0004] The patent "A Method for Preparing a Wear-Resistant Diamond Grinding Wheel with Oriented Distribution of Abrasive Grains" with the publication number CN107520770A prepares a groove array on the surface of the grinding wheel matrix by an acrylic template copying method and distributes the abrasive grains in an oriented manner, and then performs brazing treatment, which can effectively improve the processing performance and service life of the diamond grinding wheel. However, the high-temperature vaporization of the acrylic template in this technical solution will cause environmental pollution, and there are differences in the particle size of the abrasive grains themselves, resulting in inconsistent exposure heights of the abrasive grains on the surface of the grinding wheel. Moreover, the flow of the solder during the brazing process is likely to cause the deviation of the crystal orientation of the abrasive grains, resulting in excessive runout of the outer circumferential envelope surface of the grinding wheel.

[0005] The patent "A grinding wheel with regular abrasive grain shapes and orderly arrangements and a preparation method for a microstructural array" with the publication number CN118106898A prepares an orderly arranged substrate on the surface of the grinding wheel by electroplating to facilitate the CVD deposition of diamond abrasive grains, realizing the regularization of the growth, size, and shape of the abrasive grains. However, this technical solution has high requirements for the experimental environment and high preparation costs.

[0006] To improve the grinding quality and efficiency of the grinding wheel, the patent "A diamond grinding wheel with microstructures and a preparation method thereof" with the publication number CN109333385B directly grows a polycrystalline diamond coating on the SiC substrate to make the abrasive grains evenly distributed. And through picosecond pulsed laser radial processing of the diamond grinding wheel, a microstructural array with high precision and uniform regularity is manufactured on the surface of the polycrystalline diamond coating, which is beneficial for introducing grinding fluid, removing chips, and improving the wear resistance of the grinding wheel. However, in this technical solution, the preparation cost of the grinding wheel is high, the thickness of the abrasive grain layer is extremely small, and the radial processing is prone to damage the bonding strength of the abrasive grains. Moreover, the structural size is relatively macroscopic, which is prone to cause cutting chatter during the dynamic grinding process, resulting in an increase in the wear rate of the grinding wheel.

[0007] To reduce the grinding force and improve the integrity of the machined surface, the patent "A manufacturing method for a novel positive rake angle diamond grinding tool based on pulsed laser processing" with the publication number CN105728961B uses brazing and selects truncated octahedron diamond abrasive grains to make an orderly arranged diamond grinding wheel, and ensures that the top surface A of the diamond abrasive grain is parallel to the grinding wheel section where the diamond abrasive grain is located. Then, pulsed laser is used to ablate the abrasive grains in sequence, making the apex angle of the diamond abrasive grain less than 90°, changing the negative rake angle grinding method of traditional diamond grinding tools. Thereby, the dynamic effective grinding area during grinding is increased, the generation of microcracks on the machined surface is reduced, and the integrity of the machined surface is improved. However, during the rake angle processing, it is necessary to ablate a single abrasive grain at a fixed angle, with low efficiency. Moreover, the morphology of a single processed diamond abrasive grain is prone to stress concentration, increasing the probability of abrasive grain breakage and affecting the processing efficiency. Summary of the Invention

[0008] To solve the technical problems existing in the prior art, the present invention proposes a diamond grinding tool with a positive clearance angle of abrasive grains and a micro comb-tooth structure on the surface of the abrasive grains based on pulsed laser processing and a manufacturing method thereof, making the positive clearance angle of the diamond abrasive grains greater than 5°. Thereby, the additional plowing effect of the top surface of the abrasive grain on the machined surface during grinding is reduced, the grinding force is decreased, and the grinding force ratio is increased. The existence of the micro comb-tooth structure can increase the number of micro cutting edges, realize uniform micro-removal of materials, effectively reduce surface / subsurface damages such as microcracks after grinding of brittle materials, and improve the surface integrity of the materials.

[0009] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] In a first aspect, the present invention provides a method for preparing a micro-comb-tooth structure diamond grinding wheel with a positive rake angle of abrasive grains, comprising the following steps:

[0011] Step 1: Prepare grooves arranged in an orderly manner to form a certain array on the circumferential surface of the grinding wheel base, and use conductive adhesive to directionally bond diamond abrasive grains in the grooves; deposit nickel-cobalt alloy by pulse electroplating method to achieve mechanical consolidation of the abrasive grains;

[0012] Step 2: Perform tangential shaping on the grinding wheel obtained in Step 1 through a pulsed laser system to effectively control the out-of-roundness of the outer circumference of the grinding wheel;

[0013] Step 3: Perform forming machining on the positive rake angle of the abrasive grains of the grinding wheel obtained in Step 2 through a pulsed laser system;

[0014] Step 4: Perform micro-comb-tooth structure machining on the grinding wheel in Step 3 by controlling the laser overlap rate of the laser system.

[0015] As a further technical solution, in Step 1, the 100 crystal orientation is determined as the rake face and flank face of the grinding edge.

[0016] As a further technical solution, the specific process of Step 2 is as follows: Determine the center of the outer end face of the grinding wheel as the origin of the coordinate system, the XY plane as the laser focal plane, the laser is vertically incident along the -Z direction and tangent to the outer envelope contour of the grinding wheel, the uniform removal of the outer circumferential material of the grinding wheel is realized by clamping the grinding wheel through a precision electric spindle, and the uniform removal of the material in the generatrix direction of the grinding wheel is realized by the reciprocating linear motion in the X direction.

[0017] As a further technical solution, the laser parameters for shaping the grinding wheel are: laser pulse width is 20 ns, repetition frequency is 500 kHz, and laser power is 70 W.

[0018] As a further technical solution, the specific process of Step 3 is as follows: Perform forming machining on the positive rake angle of the abrasive grains of the grinding wheel by controlling the feed depth of the laser in the Y direction and the number of laser scans; during the machining process, the laser reciprocally scans along the generatrix direction of the grinding wheel to ensure the machining of the positive rake angle of all abrasive grains on the surface of the grinding wheel.

[0019] As a further technical solution, the specific process of Step 4 is as follows: Control the feed depth of the laser by moving in the Y direction, increase the laser scanning speed to reduce the laser overlap rate, analyze the influence of the defocus amount on the micro-comb-tooth structure, and realize the processing and preparation of a micro-comb-tooth diamond grinding wheel with a positive rake angle of abrasive grains.

[0020] As a further solution, in step 4, the grinding wheel is clamped on a precision electric spindle, the laser is vertically incident from the -Z direction, the grinding wheel rotates, and the laser moves back and forth linearly along the axial direction of the grinding wheel, thereby forming a series of spiral ablation trajectories on the surface of the grinding wheel.

[0021] In a second aspect, the present invention provides a diamond grinding wheel obtained by the method for preparing a diamond grinding wheel with a micro comb-tooth structure having a positive rake angle of abrasive grains.

[0022] As a further solution, in the circumferential direction of the grinding wheel, the distance between adjacent abrasive grains in adjacent rows is determined according to the residual height generated by adjacent abrasive grain rows during the grinding process; in the axial direction of the grinding wheel, the axial pitch between adjacent abrasive grains needs to satisfy that adjacent column abrasive grains complement each other's abrasive grain gaps.

[0023] As a further solution, micro comb-teeth with different depths are formed on each abrasive grain, and the positive rake angle of each diamond abrasive grain is greater than 5°.

[0024] The present invention has the following beneficial effects:

[0025] (1) First, the present invention prepares an ordered arrangement diamond grinding wheel for processing the positive rake angle of abrasive grains and the micro comb-tooth structure on the surface of abrasive grains by electroplating. The equipment required for electroplating is relatively simple, the process temperature is low, and the coating distribution is more uniform. Then, laser is used to perform tangential dressing on the grinding wheel. Compared with laser radial processing of abrasive grain microstructures, tangential dressing can reduce the damage of the laser to the grinding wheel assembly. Especially for electroplated grinding wheels, it can avoid the reduction of the consolidation strength of abrasive grains caused by the ablation removal of the coating metal during radial processing. The positive rake angle of abrasive grains is processed by a pulsed laser system. The existence of the positive rake angle of abrasive grains is beneficial to realizing the removal of materials in the plastic domain, reducing the scratching, squeezing, and plowing phenomena on the processed surface, reducing the grinding force, and reducing the subsurface damage of the workpiece. The processing of the final micro comb-tooth structure is realized by controlling the laser overlap rate, and it is not necessary to process single abrasive grains one by one, which can reduce the operation complexity and improve the processing efficiency.

[0026] (2) The present invention makes the abrasive grains on the surface of the grinding wheel arranged in an orderly manner, which can significantly increase the chip space, facilitate the flow of grinding fluid, reduce the total contact time between the grinding wheel and the workpiece, and reduce the grinding force and grinding temperature of the grinding wheel. The existence of the micro comb-tooth structure of abrasive grains can avoid problems such as the difficult control of the workpiece surface quality and the easy formation of subsurface damage during the grinding of large-grain-size grinding wheels; it can increase the number of micro grinding edges, realize the uniform removal of small amounts of materials, and improve the grinding surface quality of large-diameter diamond grinding wheels. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the orderly arrangement of abrasive grains.

[0028] Figure 2 It is a schematic diagram of the consolidation of abrasive grains.

[0029] Figure 3 It is the schematic diagram of the forming principle of the positive clearance angle of abrasive grains in laser processing.

[0030] Figure 4 It is the schematic diagram of the forming process of the positive clearance angle of abrasive grains.

[0031] Figure 5 It is the schematic diagram of abrasive grains with positive clearance angle and micro comb - tooth structure.

[0032] Figure 6(a) is the schematic diagram of the positive clearance angle of abrasive grains;

[0033] Figure 6(b) is the schematic diagram of the negative clearance angle of abrasive grains;

[0034] Figure 6(c) is the schematic diagram of the zero clearance angle of abrasive grains;

[0035] In the figure: 1. Nickel - cobalt alloy coating, 2. Grinding wheel matrix, 3. Conductive adhesive, 4. Diamond abrasive grain, 4A. Removed part of the abrasive grain, 4B. Retained part of the abrasive grain, 5. Ineffective processing area, 6. Effective processing area, 7. Positive clearance angle of abrasive grains, 8. Micro comb - tooth structure. Specific embodiments

[0036] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the present invention clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or their combinations;

[0038] Glossary: In this application, the origin of the coordinate system is defined as the center of the outer end face of the grinding wheel, and the axis direction of the grinding wheel is defined as the X - direction; the XY plane is the laser focal plane, specifically referring to Figure 3 the coordinate representation;

[0039] Furthermore, the positive clearance angle of the abrasive in the present invention means: Referring to the diamond tool, the grinding edge of the abrasive grain is the intersection line of the rake face and the flank face. The face opposite to the unprocessed surface and through which the grinding fluid flows out is the rake face, and the face opposite to the transition surface is the flank face. The angle between the flank face and the linear velocity direction of the grinding edge of the abrasive grain is the clearance angle of the abrasive grain. When the height of the flank face in the radial direction of the grinding wheel is lower than that of the grinding edge as a whole, the clearance angle of the abrasive grain is a positive clearance angle, otherwise it is a negative clearance angle; see Figure 6(a), Figure 6(b), and Figure 6(c).

[0040] In order to solve the technical problems existing in the prior art, this embodiment proposes a diamond grinding tool with a positive rake angle of abrasive grains and a micro-comb structure on the abrasive grain surface and a manufacturing method thereof, so that the positive rake angle of the diamond abrasive grains is greater than 5°, thereby reducing the additional plowing effect of the top surface of the abrasive grains on the machined surface during the grinding process, reducing the grinding force, and increasing the grinding force ratio. The existence of the micro-comb structure can increase the number of micro-cutting edges, realize uniform micro-removal of materials, effectively reduce surface / subsurface damages such as micro-cracks after grinding of hard and brittle materials, and improve the surface integrity of the materials.

[0041] Specifically, the preparation method of the micro-comb structure diamond grinding wheel with a positive rake angle of abrasive grains provided in this embodiment is as follows:

[0042] Step 1: Prepare an orderly arranged diamond grinding wheel for processing the positive rake angle of abrasive grains and the micro-comb structure on the abrasive grain surface by electroplating; specifically, prepare grooves arranged in an orderly manner to form a certain array on the circumferential surface of the grinding wheel base, and use conductive adhesive to directionally bond diamond abrasive grains in the grooves; deposit nickel-cobalt alloy by pulse electroplating method to achieve mechanical consolidation of the abrasive grains;

[0043] Step 2: Shape the grinding wheel obtained in Step 1 by a pulsed laser system; effectively control the out-of-roundness of the outer circumference of the grinding wheel;

[0044] Step 3: Perform forming processing on the positive rake angle of the abrasive grains of the grinding wheel obtained in Step 2;

[0045] Step 4: Perform micro-comb structure processing on the grinding wheel in Step 3;

[0046] In this embodiment, the laser dressing of the grinding wheel by the above pulsed laser system belongs to non-contact dressing. During the dressing process, neither macroscopic force nor tool wear is generated, and high dressing accuracy and efficiency can be maintained; the existence of the positive rake angle of the abrasive grains is beneficial to realizing plastic removal of materials, reducing scratching, squeezing and plowing phenomena on the machined surface, reducing the grinding force, and reducing subsurface damage of the workpiece; compared with laser radial processing of the abrasive grain microstructure, tangential dressing can reduce the damage of the laser to the grinding wheel body. Especially for electroplated grinding wheels, it can avoid the reduction of the abrasive grain consolidation strength caused by the ablation removal of the plating metal during radial processing. The processing of the micro-comb structure is realized by controlling the laser overlap rate, and it is not necessary to process each single abrasive grain in turn, which can reduce the operation complexity and improve the processing efficiency.

[0047] Specifically, in step 1, the diamond grinding wheel with an ordered arrangement of positive rake angle of abrasive grains and micro comb-like structures on the abrasive grain surface is prepared by electroplating method, and the diamond abrasive grain size is 20#. The ordered arrangement array is prepared by precision milling and the diamond abrasive grains are directionally bonded using conductive adhesive. Under the same stress condition, the breakage probability of the 100 crystal plane is the lowest, so the 100 crystal orientation is determined as the rake face and flank face of the grinding edge. The nickel-cobalt alloy is deposited by pulse electroplating method to achieve the mechanical consolidation of the abrasive grains. Compared with the brazing method, the electroplating method requires simpler equipment, lower process temperature, and more uniform coating distribution. It avoids the phenomenon of abrasive grain displacement caused by the melting of the solder in the brazing method.

[0048] After electroplating, the abrasive grains on the grinding wheel are arranged in an ordered and directional manner; Figure 1 is a schematic diagram of the ordered arrangement of diamond abrasive grains, where d t is the distance between adjacent abrasive grains in the circumferential direction; d a is the distance between adjacent abrasive grains in the axial direction; (since the abrasive grains are arranged in a staggered manner, the axial spacing only needs to satisfy that the adjacent column of abrasive grains complement each other's abrasive grain gaps; the circumferential spacing is calculated by combining parameters such as the grinding speed and obtaining the residual height generated by adjacent abrasive grain rows during the grinding process. If the circumferential spacing is too large, the residual height will be too large. In this patent, the theoretical residual height corresponding to the circumferential spacing is only about 9 nm) Figure 2 is a schematic diagram of abrasive grain consolidation. The diamond abrasive grains 4 are fixed on the grinding wheel base 2 through the conductive adhesive 3 and the nickel-cobalt alloy coating 1;

[0049] Specifically, as Figure 3 shown, the specific process of step 2 is as follows: Determine the center of the outer end face of the grinding wheel as the origin of the coordinate system, the XY plane as the laser focal plane, the laser is vertically incident along the -Z direction (the direction perpendicular to the XY plane) and tangent to the outer envelope contour of the grinding wheel, and the outer circumference material of the grinding wheel is uniformly removed by clamping the grinding wheel through a precision electric spindle. The material in the direction of the grinding wheel generatrix is uniformly removed by controlling the reciprocating linear motion of the laser in the X direction. As Figure 3 shown, where, after the laser is incident, an ineffective machining area 5 and an effective machining area 6 are formed; then there is formed Figure 4 the removed part 4A of the abrasive grain and the retained part 4B of the abrasive grain as shown.

[0050] Specifically, as Figure 5As shown in the figure, through the combined movement of rotational motion and linear motion in the present invention, the laser will act evenly on the surface of the abrasive grains of the entire array; during the processing, instead of processing single abrasive grains sequentially, the entire surface is processed cyclically, which is equivalent to splitting the total processing time of each abrasive grain; for example, it takes 10s to process one abrasive grain. When the laser sweeps over, abrasive grain A is processed for 0.1s. Next is abrasive grain B, but the laser will also sweep back, causing the abrasive grain to continue to be affected, and the material removal caused by each ablation action will not disappear. Therefore, after reciprocating 100 times, all abrasive grains can be processed;

[0051] Furthermore, in this embodiment, the laser parameters for dressing the grinding wheel are as follows: the laser pulse width is 20ns, the repetition frequency is 500kHz, and the laser power is 70W. Through the pulsed laser ablation effect, material removal is performed on the diamond abrasive grains. The abrasive grains with a larger exposed height have a larger material removal amount, effectively controlling the out-of-roundness of the outer circumference of the grinding wheel.

[0052] Furthermore, the XY plane is determined as the laser focal plane. Since the grinding wheel abrasive grains are relatively large and the grinding wheel is in a rotating state, there is relative movement between the abrasive grains and the laser focus, resulting in defocus, which affects the laser energy density and is reflected in the material removal efficiency. The direction of the linear velocity on the processed side of the grinding wheel is the Z direction, opposite to the laser incident direction. During the laser processing, the upper side of the abrasive grain is first affected by the laser ablation, resulting in a gradient decrease in the material removal amount of the diamond abrasive grains along the -Z direction, forming an inclined slope on the surface of the abrasive grain and forming a positive rake angle 7 of the abrasive grain.

[0053] The specific processing method corresponding to the above step 3 is as follows: After the out-of-roundness of the outer circumference of the directionally and orderly arranged grinding wheel meets the requirements, by controlling the laser radial (Y direction) feed depth and the number of scans, etc., and preferably the processing parameters of the positive rake angle of the abrasive grains, the forming processing of the positive rake angle 7 of the abrasive grains of the grinding wheel is carried out. The feed depth will significantly affect the laser action time received by a single abrasive grain and has a greater impact on the positive rake angle 7 of the abrasive grain. During the processing, the laser reciprocally scans along the generatrix direction of the grinding wheel to ensure the processing of the positive rake angle of all abrasive grains on the surface of the grinding wheel, without the need to process single abrasive grains sequentially, reducing the operation complexity and improving the processing efficiency.

[0054] Furthermore, due to the laser pulse interval, the laser spots will act evenly and discretely on the surface of the grinding wheel, forming an array of laser ablation pits arranged in a spiral line on the surface of the grinding wheel. There is an overlapping area between the adjacent spots in the axial and circumferential directions. A lower overlapping rate will result in material residue between the scanning tracks. By controlling processing parameters such as the scanning speed, the overlapping rate is controlled, and a groove-shaped micro-comb structure is formed on the flank of the abrasive grain, increasing the number of micro-cutting edges and improving the surface integrity of the processing.

[0055] Further, the specific process of machining the micro comb-tooth structure 8 on the grinding wheel obtained by machining the positive flank angle 7 of the above abrasive grains is as follows: controlling the laser feed depth through a motion platform, increasing the laser scanning speed to reduce the laser overlap rate, analyzing the influence of the defocus amount on the micro comb-tooth structure, and realizing the machining and preparation of a micro comb-tooth diamond grinding wheel with a positive flank angle of abrasive grains.

[0056] Machine the micro comb-tooth structure on the grinding wheel obtained by machining the flank angle of the above abrasive grains. Clamp the grinding wheel on a precision electric spindle, the laser is incident vertically from the -Z direction, the grinding wheel rotates, and the laser moves back and forth linearly along the axial direction of the grinding wheel, thereby forming a series of spiral ablation tracks on the surface of the grinding wheel ( Figure 5 ). The linear velocity direction of the processed side of the grinding wheel is the Z direction, which is opposite to the laser incident direction. In the machining of the micro comb-tooth structure, adjust the machining parameters to obtain a smaller overlapping area of the scanning lines, so that there is material residue on the surface of the abrasive grains, and the machining of the micro comb-tooth structure is realized. During the machining process, starting from the first row of abrasive grains, spiral ablation tracks are generated. Since the exposed height of the abrasive grains is much larger than the laser feed depth, the laser spiral ablation tracks are only reflected on the surface of the abrasive grains, forming the prototype of the micro comb-tooth structure. As the laser scans axially, the ablation tracks expand to the entire surface of the grinding wheel, and all abrasive grains are uniformly machined. However, a single laser scan cannot complete the material removal of the micro comb-tooth structure, and repeated laser scans are required. The accumulation of thermal effects between the overlapping areas will increase the size of the micro comb-tooth structure and improve the uniformity of the micro comb-tooth structure on the surface of the abrasive grains. First, adjust the laser incident distance in the Z direction to make the XY plane in a defocus state. The defocus state is beneficial to reducing the dispersion degree of the laser spot acting on the surface of the abrasive grains and is beneficial to the formation of the micro comb-tooth structure. Then calculate the laser overlap rate through the existing laser machining parameters to determine the appropriate laser scanning line speed, and set the laser to reciprocate and scan at this line speed. A lower laser overlap rate will cause uneven material removal on the surface of the abrasive grains and form a micro comb-tooth structure. To ensure the uniformity of the micro comb-tooth structure on the surface of all abrasive grains, control the number of repeated laser scans. Excessive scan times will cause the size of the micro comb-tooth structure to decrease. During the repeated laser scanning process, pause regularly and use a portable microscope to observe the machining situation on the surface of the abrasive grains. After machining, use a laser microscope to measure the three-dimensional morphology of the micro comb-tooth structure, and realize the machining and preparation of a micro comb-tooth diamond grinding wheel with a positive flank angle of abrasive grains.

[0057] The specific embodiments are as follows:

[0058] A nanosecond pulsed laser is used, and the specific parameters are: wavelength 1064 nm, pulse width 20 ns, and pulse frequency 500 kHz.

[0059] Install the diamond grinding wheel with oriented and ordered arrangement, which is prepared by electroplating method and shaped, on the electric spindle. Adjust the position of the outer circle surface of the grinding wheel relative to the laser focus, and scan the grinding wheel with a laser beam. Conduct the forming machining test of the positive rake angle of the abrasive grains of the diamond grinding wheel from several laser process parameters, including laser power, grinding wheel speed, radial feed depth, and number of scanning times. After the machining is completed, use a laser confocal microscope to observe the surface morphology of the abrasive grains and measure the rake angle. When the average laser power P = 70 W, the grinding wheel speed n = 6000 r / min, the laser repeated scanning times t = 360, and the feed depth a = 0.1 mm, the average positive rake angle of the abrasive grains can be obtained as 5.68°.

[0060] After the machining of the positive rake angle of the abrasive grains is completed, conduct the machining test of the micro comb tooth structure of the diamond grinding wheel from several laser process parameters, including axial scanning speed, defocus amount, and number of scanning times. When the laser axial scanning speed v = 2 mm / s, the defocus amount Δ = -0.1 mm, and the laser repeated scanning times t = 60, the average height of the teeth of the micro comb tooth structure on the surface of the abrasive grains is 7.5 μm, and the average width of the teeth is 11.88 μm.

[0061] By studying the influence laws of different laser process parameters on the positive rake angle of the abrasive grains and the parameters of the micro comb tooth structure on the surface of the abrasive grains, a large-particle-size diamond grinding wheel with an oriented arrangement, a relatively large rake angle, and a relatively obvious micro comb tooth structure is obtained.

Claims

1. A preparation method of a diamond grinding wheel with a micro-comb tooth structure having a positive rake angle of abrasive grains, characterized in that, It includes the following steps: Step 1: Prepare grooves arranged in an orderly manner to form a certain array on the circumferential surface of the grinding wheel base body through precision milling, and use conductive adhesive to directionally bond diamond abrasive grains in the grooves; deposit nickel-cobalt alloy by pulse electroplating method to achieve mechanical consolidation of the abrasive grains. Step 2: Shape the grinding wheel obtained in Step 1 through a pulsed laser system to effectively control the out-of-roundness of the outer circumference of the grinding wheel. Step 3: Perform forming machining on the positive rake angle of the abrasive grains of the grinding wheel obtained in Step 2. Step 4: Process the grinding wheel in Step 3 with a micro comb structure by controlling the laser overlap rate of the laser system.

2. The preparation method of the diamond grinding wheel with a micro-comb tooth structure having a positive rake angle of abrasive grains as claimed in claim 1, characterized in that, In Step 1, determine the 100 crystal direction of the diamond abrasive grain as the rake face and flank face of the grinding edge.

3. The preparation method of the diamond grinding wheel with a micro-comb tooth structure having a positive rake angle of abrasive grains according to claim 1, characterized in that, The specific process of Step 2 is as follows: Determine the center of the outer end face of the grinding wheel as the origin of the coordinate system, the XY plane as the laser focal plane, the laser is vertically incident along the -Z direction and tangent to the outer envelope contour of the grinding wheel, and the grinding wheel is clamped by a precision motorized spindle to achieve uniform removal of the material on the outer circumference of the grinding wheel, and control the laser to move linearly back and forth in the X direction to achieve uniform removal of the material in the direction of the grinding wheel busbar.

4. The preparation method of the diamond grinding wheel with a micro-comb tooth structure having a positive rake angle of abrasive grains as described in claim 1, characterized in that, The laser parameters for shaping the grinding wheel are: laser pulse width is 20 ns, repetition frequency is 500 kHz, and laser power is 70 W.

5. The preparation method of the diamond grinding wheel with a micro-comb tooth structure having a positive rake angle of abrasive grains according to claim 1, characterized in that, The specific process of Step 3 is as follows: Perform forming machining on the positive rake angle of the abrasive grains of the grinding wheel by controlling the feed depth of the laser in the Y direction and the number of laser scans; during the machining process, the laser scans back and forth along the direction of the grinding wheel busbar to ensure the machining of the positive rake angle of all abrasive grains on the surface of the grinding wheel.

6. The preparation method of the diamond grinding wheel with a micro-comb tooth structure having a positive rake angle of abrasive grains according to claim 1, characterized in that, The specific process of Step 4 is as follows: Control the feed depth of the laser by moving in the Y direction, increase the laser scanning speed to reduce the laser overlap rate, analyze the influence of the defocus amount on the micro comb structure, and achieve the processing and preparation of a micro comb diamond grinding wheel with a positive rake angle of the abrasive grains.

7. The preparation method of the diamond grinding wheel with a micro-comb tooth structure having a positive rake angle of abrasive grains according to claim 1, characterized in that, In Step 4, the grinding wheel is clamped on a precision motorized spindle, the laser is vertically incident from the -Z direction, the grinding wheel rotates, and the laser moves linearly back and forth along the axis of the grinding wheel, thereby forming a series of spiral ablation trajectories on the surface of the grinding wheel.

8. A diamond grinding wheel, characterized in that, It is obtained by the method for preparing a micro comb structure diamond grinding wheel with a positive rake angle of abrasive grains according to any one of claims 1-7.

9. The diamond grinding wheel according to claim 8, wherein, In the circumferential direction of the grinding wheel, the distance between adjacent rows of abrasive grains is determined according to the residual height generated by adjacent rows of abrasive grains during the grinding process; in the axial direction of the grinding wheel, the axial pitch of adjacent abrasive grains needs to meet the requirement that adjacent columns of abrasive grains complement each other's abrasive grain gaps.

10. The diamond grinding wheel according to claim 8, wherein, Micro combs with different depths are formed on each abrasive grain, and the positive rake angle of each diamond abrasive grain is greater than 5°.

Images