Method for Measuring Coating Adhesion of Coated Abrasives and Method for Quality Inspection

Abstract

The present invention provides a method for measuring the coating adhesion of coated abrasives, comprising the steps of: providing a coated abrasive particle, and determining a first surface and a second surface of the coated abrasive particle; removing the coating layer on the first surface of the coated abrasive particle to expose the first surface of the original abrasive, and the exposed part of the original abrasive is undamaged; using a second laser to irradiate downward from the first surface of the original abrasive, and heating the original abrasive until the coating layer on the second surface bursts, and calibrating the coating adhesion of the coated abrasive under the laser heating conditions at this time. The above measurement method can measure the adhesion between the abrasive particle and the coating layer, is applicable to industrial production, can simply and conveniently monitor whether the production process of the coated abrasive is qualified, improve the product qualification rate, and reduce the production cost. The present invention provides a detection method for detecting the quality of coated abrasives using the above method.

Description

Technical Field

[0001] The present invention belongs to the field of superhard materials, and specifically relates to a method for measuring the coating adhesion of coated abrasives and a method for quality inspection. Background Art

[0002] The production process of coated abrasives includes crushing of raw abrasives, surface cleaning of raw abrasives, electroplating or electroless plating. If the cleaning is not thorough or the coating parameters are abnormal, the adhesion between the coating layer and the abrasive particles will be insufficient. During the subsequent use of the coated abrasive particles, the holding force of the coating layer on the raw abrasives is insufficient, and the coated abrasive particles are likely to fall off and fail in advance. Therefore, it is necessary to measure the coating adhesion of the abrasives.

[0003] However, since the particle size of the raw abrasives is usually 40 - 300 microns, which is too small and the morphological differences are huge, as Figure 1 shown, conventional adhesion measurement methods such as scratch testers cannot be applied. Therefore, it is difficult for the existing technology to measure the adhesion of coated abrasives. In the actual application process, the adhesion of the coating on the surface of the raw abrasives is usually evaluated by the performance of the coated abrasives in actual use. However, this evaluation method requires a large amount of statistical data on the use of coated abrasives, relies on the feedback of users, and has serious hysteresis. It cannot detect the abnormality of the production process in time, which greatly increases the production cost. Enterprises have a need for a simple measurement of the adhesion of coated abrasives. Adhesion is an effective means to monitor the production process of coated abrasives, which can detect the process abnormalities of cleaning and coating in time, quickly judge whether the product is qualified and the grade of the product. Summary of the Invention

[0004] In view of this, it is necessary for the present invention to provide a method for measuring the coating adhesion of coated abrasives and a method for quality inspection. This measurement method can measure the adhesion between abrasive particles and the coating layer, is applicable to industrial production, can simply and conveniently monitor whether the production process of coated abrasives is qualified, improve the product qualification rate, and reduce the production cost.

[0005] For this purpose, the present invention mainly uses the tolerance of the coating on the surface of the abrasive to the stress caused by the thermal expansion (or called thermal shock) of the abrasive itself to calibrate the adhesion between the coating and the abrasive. It is not necessary to accurately measure how many Newtons the adhesion is, that is, the method provided by the present invention does not need to measure the standard adhesion data to monitor whether the production process is stable and whether the product is qualified.

[0006] Specifically, the present invention provides a method for measuring the coating adhesion of coated abrasives, including the steps:

[0007] Step 1. Provide a coated abrasive grain, which consists of a raw abrasive and a coating layer that completely coats the surface of the raw abrasive. The coated abrasive grain has a first surface and a second surface that are oppositely arranged, and the coating layers on the first surface and the second surface form a complete wrap of the raw abrasive. Divide the first surface and the second surface by the maximum horizontal cross-section of the coated abrasive grain.

[0008] Step 2. Remove the coating layer on the first surface of the coated abrasive grain to expose the first surface of the raw abrasive, and the exposed part of the raw abrasive is not damaged.

[0009] Step 3. Use a second laser to irradiate downward from the first surface of the raw abrasive and heat the raw abrasive until the coating layer on the second surface bursts, and calibrate the coating adhesion of the coated abrasive grain under the current laser heating conditions.

[0010] Herein, the "raw abrasive" refers to the original superhard abrasive that has not undergone the coating process, such as superhard materials like cubic boron nitride, diamond, or silicon carbide. Preferably, the size of the raw abrasive is 40 - 300 microns. The material of the coating layer is preferably a metal material, such as nickel or titanium; it can also be a metal composite material, carbide, nitride, etc.

[0011] The "maximum horizontal cross-section" herein refers to a horizontal plane when the coated abrasive is cut in the horizontal direction, and this horizontal cutting plane coincides with the plane where the maximum linear diameter of the raw abrasive is located in the horizontal direction. The maximum linear diameter refers to the maximum radial length of the particle. Dividing the first surface and the second surface in this way is to facilitate the almost complete removal of the coating layer on the first surface, especially the coating layer on the side surface, when using a laser to remove the coating layer on the first surface, because at this time, only the first surface needs to be scanned perpendicular to the laser beam, and almost no inclined laser beam is needed to remove the coating layer on the side surface.

[0012] Based on the above, Step 2 includes: using a first laser to heat the coating layer on the first surface of the coated abrasive grain to vaporize the coating layer on the first surface and expose the first surface of the raw abrasive. Among them, in the process of removing the coating layer on the first surface of the coated abrasive grain, the coating layer on the first surface of the coated abrasive grain should be removed exactly as much as possible without damaging the exposed raw abrasive.

[0013] Step 2 should basically completely remove the coating layer on the first surface, mainly to reduce the thermal effect of the second laser on the coating layer on the second surface when the second laser tests the coating layer on the second surface later. If there is a lot of residue on the coating layer on the first surface, then when the second laser heats the raw abrasive, more heat needs to be conducted to the coating layer on the second surface, which is not conducive to establishing the thermal difference between the coating layer and the raw abrasive and is not conducive to the rupture of the second coating layer.

[0014] Based on the above, the first laser is a high-power short-pulse laser, and the depth of the thermal effect generated by the first laser is limited to the coating layer on the first surface. The wavelength of the first laser is 240 - 460 nm, such as lasers with wavelengths of 247 nm, 337 nm, 409 nm, and 413 nm. Among them, the wavelength of the first laser is mainly selected according to the material of the coating layer.

[0015] The purpose of limiting the depth of the thermal effect generated by the first laser to the coating layer on the first surface is to prevent the first laser from significantly heating the original abrasive and the coating layer on the second surface, so as not to affect the measurement accuracy. Preferably, the conditions that the first laser heating the coating layer on the first surface should meet are: in the depth direction perpendicular to the first surface, when going down from the first surface, when the depth reaches half, the temperature does not exceed 300 °C.

[0016] Based on the above, step three includes: using the second laser to vertically irradiate the first surface of the original abrasive, and making the irradiation area of the second laser on the first surface of the original abrasive cover the center of the maximum horizontal cross-section, not exceeding the maximum horizontal cross-section, and not greater than 3 / 4 of the area of the maximum horizontal cross-section. Among them, the spot diameter of the second laser is 10 - 100 microns; adjusting the heating conditions of the second laser until the coating layer on the second surface bursts, and calibrating the coating binding force of the coated abrasive with the heating conditions of the second laser at this time.

[0017] Based on the above, in step three, the second laser also selects a suitable wavelength and pulse width to heat the original abrasive in the direction perpendicular to the first surface of the original abrasive, and the focus of the second laser does not exceed half of the depth of the coated abrasive particle when going down from the first surface of the original abrasive; changing the power of the second laser until the coating layer on the second surface bursts, and calibrating the coating binding force of the coated abrasive with the power of the second laser at this time.

[0018] Based on the above, the wavelength of the second laser is greater than the wavelength of the first laser, and the second laser can be a laser with a wavelength less than 700 nm. Specifically, the second laser is a laser with a wavelength in the range of 400 - 700 nm. More specifically, the second laser can be lasers with wavelengths of 460, 488, 532, 694 nm, etc.

[0019] Based on the above, step three includes: first filling the first surface of the original abrasive with a material having the same or similar refractive index as the original abrasive to form a horizontal plane, and then using the second laser to irradiate and heat the original abrasive from the first surface of the original abrasive downward.

[0020] Based on the above, the method for filling the first surface of the original abrasive into a horizontal plane includes: forming a planarization layer on the first surface of the original abrasive by means of drop coating, and the refractive index of the planarization layer is the same as or close to that of the original abrasive.

[0021] Among them, the planarization layer can be a material layer such as silicon oxide, TiO2 or Ta2O5 prepared by a solution method, which has high transparency to reduce the absorption of the second laser, and at the same time has a high refractive index and is close to or the same as the refractive index of the original abrasive. Taking cubic boron nitride as an example, the refractive index is about 2.1, while the refractive index of silicon oxide is 1.8 - 1.9, TiO2 is 2.2 - 2.3, and Ta2O5 is 2.1 - 2.3. Any of the three can be used separately or in combination.

[0022] It is specifically stated herein that in production, it is generally considered that the bonding force between the plating layer and the original abrasive is the same for abrasive particles of the same batch. It is usually difficult to calibrate the bonding force of the plating layer of the plated abrasive by irradiating with the second laser only once in the step three. Therefore, when changing the heating conditions of the second laser, new plated abrasive particles need to be replaced to avoid multiple tests of the second laser on the same plated abrasive particles. Otherwise, the thermal effect of the previous second laser test step will affect the accuracy of the subsequent test.

[0023] The present invention also provides a method for detecting the quality of plated abrasives, including:

[0024] Step 1: Select batches of plated abrasive particles whose grinding performance of the grinding tools made of the plated abrasive particles is at the qualified line according to the grinding performance of the grinding tools;

[0025] Step 2: Adopt the above bonding force measurement method to measure the bonding force of the plated abrasive particles selected in Step 1 that are at the qualified line, and calibrate this bonding force as the qualified bonding force standard value of the plated abrasive particles;

[0026] Step 3: First, adopt the same bonding force measurement method as in Step 2 to detect the bonding force of the newly produced plated abrasive particles of the same specification on the production line, and calibrate the sample bonding force detection value; then compare the sample bonding force detection value with the qualified bonding force standard value to determine whether the newly produced plated abrasive particles of the same batch on the production line are qualified or unqualified.

[0027] Based on the above detection method, Step 1 includes: selecting multiple batches of plated abrasive particles, taking a part from the same batch of sampled samples to make the grinding tool, and leaving a part for subsequent measurement; determining the quality grades of different batches of plated abrasive particles according to the actual grinding performance of the grinding tool, and screening out the batches of plated abrasive particles whose grinding performance of the grinding tool is at the qualified line;

[0028] Step 2 includes: adopting the above-mentioned bonding force measurement method, under the condition that the wavelength and pulse width of the second laser are the same, detecting and determining the second laser power when the coating layer on the second surface of the coated abrasive grains selected in Step 1 and located on the qualified line bursts, and at this time, calibrating the qualified bonding force standard value with this second laser power;

[0029] Step 3 includes: adopting the same method as in Step 2, detecting and determining the second laser power when the coating layer on the second surface of the newly produced coated abrasive grains of the same specification on the production line bursts, and calibrating the sample bonding force detection value with this; if the sample bonding force detection value is not less than the qualified bonding force standard value, it is determined that the newly produced coated abrasive grains of the same batch on the production line are qualified; if the sample bonding force detection value is less than the qualified bonding force standard value, it is determined that the newly produced coated abrasive grains of the same batch on the production line are qualified.

[0030] Therefore, the bonding force measurement method provided by the present invention mainly uses the tolerance degree of the stress caused by the thermal expansion (or called thermal shock) of the coating layer on the surface of the original abrasive to the original abrasive itself to calibrate the bonding force between the coating and the abrasive. Without accurately measuring how many Newtons the bonding force is, it can monitor whether the production process of the coated abrasive is stable and whether the product is qualified, thus simplifying the detection method for the quality of coated abrasive grains and solving the problem of difficult quantitative determination of the bonding force of abrasive grains.

[0031] In addition, the detection method for the quality of the coated abrasive provided by the present invention has a short cycle, can timely detect abnormalities in the production process, improve the product qualification rate, and improve the process stability of the production line. Description of the Drawings

[0032] Figure 1 is the common crystal form of cubic boron nitride.

[0033] Figure 2 is a schematic diagram for dividing the first surface and the second surface of the spherical coated abrasive grains provided by the embodiment of the present invention.

[0034] Figure 3 is a schematic diagram of the light refraction when the second laser irradiates irregular abrasive grains.

[0035] Figure 4 is a schematic diagram of the structure of the planarization layer formed in the second embodiment of the present invention.

[0036] Among them, the reference signs of the components in each figure: 1 first surface, 2 second surface, 3 maximum horizontal cross-section, 4 upper surface, 5 incident laser 5, 6 refracted light, 7 normal line, 8 original abrasive, 9 planarization layer, 10 test platform. Detailed Embodiments

[0037] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0038] Example 1

[0039] This embodiment provides a method for measuring the coating adhesion of nickel-plated cubic boron nitride abrasives, including the steps of:

[0040] Step 1: Determine the first surface and the second surface of the nickel-plated cubic boron nitride abrasive particles

[0041] Provide nickel-plated cubic boron nitride abrasive particles, which are plated with a nickel layer on the surface of cubic boron nitride particles by electroplating, and the nickel layer accounts for 60% of the mass of the nickel-plated cubic boron nitride abrasive particles. Please refer to Figure 2 , in this embodiment, the nickel-plated cubic boron nitride abrasive particles are spherical, having a first surface 1 and a second surface 2 opposite to the first surface 1. The plating layers on the first surface 1 and the second surface 2 form a complete wrap of the abrasive. The first surface 1 and the second surface 2 are divided by the maximum horizontal cross-section 3.

[0042] Among them, the maximum horizontal cross-section 3 refers to the horizontal plane obtained by horizontally cutting the nickel-plated cubic boron nitride abrasive particles placed on a horizontal table, and the cutting position coincides with the plane where the maximum line diameter of the nickel-plated cubic boron nitride abrasive particles is located in the horizontal direction. The nickel-plated cubic boron nitride abrasive particles in this embodiment divide the first surface 1 and the second surface 2 in this way to facilitate the subsequent removal of the nickel layer on the first surface.

[0043] Step 2: Remove the nickel layer on the first surface

[0044] Use the laser method to substantially completely remove the nickel layer on the first surface of the nickel-plated cubic boron nitride abrasive particles to expose the original cubic boron nitride abrasive on the first surface. Specifically, place the nickel-plated cubic boron nitride abrasive particles on a laser test bench, and try to ensure that its first surface is generally a horizontal plane, so as to facilitate the use of the first laser to scan the upper surface and the side surface of the first surface of the nickel-plated cubic boron nitride abrasive particles, so that the nickel layer on the first surface is vaporized to quickly remove the nickel layer on the first surface and expose the original cubic boron nitride abrasive. The nickel-plated cubic boron nitride abrasive particles in this embodiment are spherical. The first laser only scans the coating on the first surface with a vertically downward laser beam, and almost no inclined laser beam is needed to completely remove the nickel layers on its upper surface and side surface at the same time.

[0045] The first laser is a high-power short-pulse laser, and the depth of the thermal effect is limited to the nickel plating layer on the first surface. The limitation of the thermal effect to the nickel plating layer on the first surface means that there is no significant heating of the second surface of the nickel-plated cubic boron nitride abrasive particles or the nickel plating layer on the second surface; preferably, it is ensured that in the depth direction perpendicular to the first surface of the nickel-plated cubic boron nitride abrasive particles (i.e., in the vertical direction), when the depth reaches half from the first surface downwards, the temperature of the nickel-plated cubic boron nitride abrasive particles does not exceed 300 °C. In this embodiment, the first laser beam is a laser with a short wavelength, specifically an ultraviolet laser with a wavelength of 337 nm; because the shorter the wavelength, the easier it is to control the penetration depth to be smaller. In this way, mainly to ensure that when the first laser removes the nickel plating layer on the first surface, it can basically remove the nickel plating layer and will not have an obvious heating effect on the original cubic boron nitride abrasive, so as to prevent annealing of the nickel plating layer on the second surface and make the measurement inaccurate.

[0046] This step basically completely removes the nickel plating layer on the first surface, mainly to reduce the thermal effect of the second laser on the nickel plating layer on the second surface when the second laser tests the nickel plating layer on the second surface. If there is a lot of residue on the nickel plating layer on the first surface, then when the second laser heats the cubic boron nitride particles, more heat needs to be conducted to the nickel plating layer on the second surface, which is not conducive to establishing the thermal difference between the nickel plating layer and the cubic boron nitride particles and is not conducive to the rupture of the nickel plating layer on the second surface.

[0047] Of course, in addition to the above laser method, this step can also use a liquid etching method, a dry etching method, a mechanical removal method or a laser irradiation method to remove the nickel plating layer on the first surface of the nickel-plated cubic boron nitride abrasive particles, exposing the first surface of the cubic boron nitride particles.

[0048] Step Three: Calibrate the bonding force

[0049] Irradiate the first surface with a second laser to laser-heat the exposed cubic boron nitride particles, change the heating conditions, and record the heating conditions when the nickel plating layer on the second surface bursts and falls off, so as to calibrate the bonding force of the nickel plating layer.

[0050] Specifically, first, a second laser with a spot diameter of 10 to 100 μm and a wavelength of 532 nm is perpendicularly irradiated onto the first surface of the cubic boron nitride particles, and the irradiation area of the second laser on the first surface of the cubic boron nitride particles covers the center of the maximum horizontal cross-section, does not exceed the maximum horizontal cross-section, and is not greater than 3 / 4 of the area of the maximum horizontal cross-section. At the same time, the focus of the second laser does not exceed half of the depth of the nickel-plated cubic boron nitride abrasive particles from the first surface of the cubic boron nitride particles; then, adjust the power of the second laser until the nickel plating layer on the second surface bursts, and calibrate the coating adhesion of the coated abrasive with the laser power at this time. In this embodiment, 600 mW is used as the starting power to determine whether the nickel plating layer on the second surface can burst; if it does not burst, replace it with another abrasive of the same batch, and with an increment of 50 mW, that is, a second laser of 650 mW, to detect whether the nickel plating layer on the second surface bursts. If it still does not burst, take the third abrasive of the same batch for the second laser measurement, and so on, until the nickel plating layer on the second surface bursts; finally, the coating on the second surface bursts at a second laser power of 800 mW. Therefore, the coating adhesion of the nickel plating layer of this batch is 800 mW.

[0051] Example 2

[0052] This embodiment provides a method for measuring the coating adhesion of copper-plated cubic boron nitride abrasives. This measurement method is basically the same as the measurement method provided in Example 1. The main differences are as follows: The abrasive particles used in this embodiment are copper-plated cubic boron nitride abrasive particles, and their particle shapes are diverse; the parameters of each step are different; in step three, it also adds a step of first filling the first surface with a material having the same or similar refractive index as the cubic boron nitride particles to form a horizontal plane. For the remaining processes not described in detail, refer to Example 1.

[0053] Among them, the specific differences are as follows:

[0054] In step one, the copper-plated cubic boron nitride abrasive particles are composed of cubic boron nitride particles with the shape shown as Figure 1 and a copper plating layer plated on the surface of the cubic boron nitride particles by electroless plating. The copper plating layer accounts for 55% of the mass of the copper-plated cubic boron nitride abrasive particles;

[0055] In step two, the first laser is an ultraviolet laser with a wavelength of 409 nm;

[0056] In the third step, when the second laser beam irradiates and heats the first surface of the original abrasive, it is necessary to ensure that the light beam propagates downward along the plumb line in the original abrasive. Among them, the coated abrasive grains are subject to coating treatment, and their appearance may be relatively round and square shapes such as spherical-like or square-like. When placing the coated abrasive grains on the laser test bench, try to ensure that the first surface is generally horizontal to facilitate the irradiation of the first laser and the second laser. However, after the coating layer on the first surface is removed from the coated abrasive grains through the second step, the first surface of the exposed original abrasive is mostly irregular in shape, such as Figure 1 as described, usually without a horizontal upper surface.

[0057] The upper surface of the original abrasive is not a horizontal plane but various inclined surfaces, which will make it difficult for the second laser beam to irradiate and reach a specific depth in the opposite direction of the plumb line. Because if the upper surface 4 is an inclined surface, the incident laser 5 incident vertically will be refracted, and the refracted light 6 will deviate from the plumb direction of the normal line 7. When irradiating on inclined surfaces with different inclined directions, it may even directly irradiate on the second coating layer on the side, as Figure 3 shown. For the same coated abrasive grain, different placement forms, such as the upper surface of the exposed original abrasive may be placed horizontally, placed at a large angle of inclination, placed at a small angle of inclination, etc.; thus, the light heating effect caused by the vertically irradiated second laser has significant differences, making the test of the bonding strength lack unity and repeatability.

[0058] To eliminate the randomness caused by the inclination direction of the first surface of the original abrasive to the test results, in the third step, a material with the same or close refractive index as the original abrasive is first used to fill the first surface of the original abrasive into a horizontal plane, and then the second laser is used to irradiate and heat the original abrasive downward from the first surface of the original abrasive. In this embodiment, a layer of flattening layer 9 as Figure 4 shown is drop-coated on the first surface of the original abrasive 8. The flattening layer 9 has the same or close refractive index as the original abrasive 8 after drying. If the refractive index of the flattening layer is significantly different from that of the original abrasive, although the upper surface 4 after drop-coating is a plane and the incident light 5 propagates vertically downward in the flattening layer 9, when it reaches the interface between the flattening layer and the original abrasive, refraction still occurs, resulting in the propagation direction deviating from the normal line.

[0059] When drop - coating the planarization layer 9, ensure that the planarization layer 9 does not reach the bottom of the coated abrasive grains, especially the position at the center of the bottom of the coated abrasive grains where cracking and peeling will occur, to prevent affecting the bonding strength test results. The test platform 10 is a platform with through - holes of different apertures. Place the coated abrasive grains on a hole of a suitable size so that the size of the coated abrasive grains is slightly larger than the aperture, just so that they will not fall into the hole. At the same time, separate the position of the cracking and peeling of the coating layer on the second side 2 from the first side of the original abrasive 8, especially from the upper surface of the grains, to avoid the planarization layer reaching the second side 2 after drying when drop - coating the first side of the original abrasive 8 and leaking out as large an area as possible of the second side 2.

[0060] In this embodiment, after the copper - coating layer on the first side of the copper - coated cubic boron nitride abrasive grains is removed in the second step, the first side of the cubic boron nitride grains therein is exposed. A mixed sol is drop - coated on the first side of the cubic boron nitride grains and dried to form a planarization layer. Among them, the mixed sol is a mixture of silica sol and titania sol. The planarization layer is a combination of silica with a refractive index of 1.9 and TiO2 with a refractive index of 2.2, and the overall refractive index is 2.1, which is the same as the refractive index of the cubic boron nitride grains.

[0061] After forming the planarization layer in the third step, then use the second laser to irradiate and heat the cubic boron nitride grains from the first side of the cubic boron nitride grains downwards. The heating method is the same as the corresponding heating method provided in the first embodiment. The main difference is that: in this embodiment, the spot diameter of the second laser used is 80 microns and the wavelength is 488 nm; the starting power of the second laser is 700 mW to irradiate the planarization layer, and the copper - coating layer on its second side does not burst; replace another copper - coated cubic boron nitride abrasive grain of the same batch, with an increment of 50 mW, that is, use a second laser of 750 mW to detect that the copper - coating layer on the second side still does not burst; take the third copper - coated cubic boron nitride abrasive grain of the same batch, use a second laser of 800 mW to detect that the copper - coating layer on the second side bursts rapidly; take the fourth copper - coated cubic boron nitride abrasive grain of the same batch, with a decrement of 10 mW, that is, use a second laser of 790 mW to detect that the copper - coating layer on the second side still bursts rapidly; take the fifth copper - coated cubic boron nitride abrasive grain of the same batch, use a second laser of 780 mW to detect the copper - coating layer on the second side, and the copper - coating layer bursts; take the sixth copper - coated cubic boron nitride abrasive grain of the same batch, use a second laser of 770 mW to detect the copper - coating layer on the second side, and the copper - coating layer does not burst. Therefore, in this embodiment, the copper - coating layer on the second side bursts at a second - laser power of 780 mW, so the bonding strength of the copper - coating layer of this batch is 780 mW.

[0062] Embodiment Three

[0063] This embodiment provides a method for measuring the coating adhesion of titanium-plated diamond abrasives. This measurement method is basically the same as the measurement method provided in Embodiment 2. The main differences are as follows: The parameters of the plated abrasive particles, the first laser, and the second laser are all different; for the remaining processes not described in detail, refer to Embodiment 2. Specifically, the differences are as follows:

[0064] In the first step, the titanium-plated diamond abrasive particles are composed of diamond particles and a titanium-plated layer plated on the surface of the diamond particles by electroless plating, and the titanium-plated layer accounts for 45% of the mass of the titanium-plated diamond abrasive particles.

[0065] In the second step, the first laser used is an ultraviolet laser with a wavelength of 247 nm;

[0066] In the third step, the spot diameter of the second laser used is 40 microns and the wavelength is 694 nm; 800 mW is used as the starting power of the second laser to detect whether the titanium-plated layer on the second surface bursts. After detection, in this embodiment, the titanium-plated layer on the second surface bursts at a second laser power of 800 mW, so the adhesion of the titanium-plated layer in this batch is 800 mW.

[0067] Embodiment 4

[0068] The embodiment of the present invention provides a method for detecting the quality of nickel-plated cubic boron nitride abrasives, including the following three steps.

[0069] Step 1: Select the original abrasive batch of the grinding wheel that meets the qualified line according to the cutting performance of the grinding wheel made of nickel-plated cubic boron nitride abrasives.

[0070] This step includes: Selecting multiple batches of nickel-plated cubic boron nitride abrasives, taking out a part from the same batch of sampled samples to make grinding wheels, and leaving a part for subsequent measurement; determining the quality grades of abrasives in different batches according to the actual grinding performance of the grinding wheels, and selecting the abrasive batches that meet the adhesion qualified line. In this embodiment, a total of five batches of samples are drawn.

[0071] In this embodiment, this step specifically includes: First, providing nickel-plated cubic boron nitride abrasives produced from the same batch as the sampling samples, which are the same as the nickel-plated cubic boron nitride abrasives provided in Embodiment 1; Second, taking out a part from the sampling samples to make nickel-plated cubic boron nitride grinding wheels, and the grinding wheels use resin binders; Third, cutting and processing bearing workpieces with the nickel-plated cubic boron nitride grinding wheels, and determining the quality grades of the nickel-plated cubic boron nitride abrasive samples according to the processing results, and determining that the sampling samples are unqualified samples, good samples, or excellent samples. Among them, good samples and excellent samples are both qualified samples.

[0072] According to statistical data, a nickel-plated cubic boron nitride grinding wheel of the same specification should be able to cut at least 26 workpieces, which is the qualified line for the grinding wheel. In this embodiment, five batches of samples were taken and processed 31, 29, 32, 27, and 20 workpieces respectively; the retained sample of the abrasive of the batch that cut 27 workpieces was taken. The number of workpieces cut by the grinding wheel of this batch is the closest to the empirical qualified value, and the abrasive of this batch is exactly the abrasive at the qualified bonding strength line.

[0073] Step 2: Measure the bonding strength of the nickel-plated cubic boron nitride abrasive of the batch at the qualified line, and this bonding strength calibrates the qualified bonding strength standard value of the nickel-plated cubic boron nitride abrasive.

[0074] Use the bonding strength measurement method provided in Example 1 to detect the bonding strength of the retained sample of the fourth batch of nickel-plated cubic boron nitride abrasive at the qualified line determined in Step 1; in this embodiment, the bonding strength of the qualified batch of nickel-plated cubic boron nitride abrasive is calibrated to the second laser power of 750 mW. Therefore, the qualified bonding strength standard value of this specification of nickel-plated cubic boron nitride abrasive is 750 mW.

[0075] Step 3: Detect and classify the nickel-plated cubic boron nitride abrasive products on the production line.

[0076] Perform a bonding strength test on the nickel-plated cubic boron nitride abrasive of the same specification on the production line, and measure its bonding strength using the method in Step 2 above. The nickel-plated layer on the second surface of the sample bursts at the second laser power of 800 mW, so the bonding strength of the sample sampled from the production line is 800 mW, which is higher than the qualified bonding strength standard value of 750 mW. Therefore, the nickel-plated cubic boron nitride abrasive on the production line is of excellent quality.

[0077] Example 5

[0078] The embodiment of the present invention provides a method for detecting the quality of copper-plated cubic boron nitride abrasive. This detection method is basically the same as the detection method provided in Example 4, and the main difference is that:

[0079] In Step 1, the copper-plated cubic boron nitride abrasive is made into a grinding wheel, and this grinding wheel is used to cut bearing workpieces; according to statistics: a copper-plated cubic boron nitride grinding wheel of the same specification should be able to cut at least 35 workpieces, which is the qualified line for the grinding wheel. Among them, the batch that cut 36 pieces in the five batches of samples is the sample closest to the statistical qualified line, and the deviation of other batches is greater than that of this batch. Therefore, the retained sample of the abrasive of the batch whose grinding wheel was scrapped after cutting 36 workpieces in the five batches of samples taken in this embodiment is used to detect the qualified bonding strength standard value subsequently.

[0080] In Step 2, the bonding strength of the copper-plated cubic boron nitride abrasive samples determined in Step 1 and located at the qualified line is detected by using the bonding strength measurement method provided in Embodiment 2. In this embodiment, the bonding strength of the qualified batch of copper-plated cubic boron nitride abrasives is determined and calibrated as the second laser power of 850 mW. Therefore, the qualified bonding strength standard value of this specification of copper-plated cubic boron nitride abrasives is 850 mW.

[0081] In Step 3, by using the bonding strength measurement method provided in Embodiment 2, the bonding strength of the copper-plated cubic boron nitride abrasives of the same specification on the production line is tested. When the copper-plated layer on the second surface of the sample bursts at the second laser power of 780 mW, the bonding strength of the samples sampled from the production line is 780 mW, which is significantly lower than the qualified bonding strength standard value of 850 mW. This batch of samples is unqualified. The product needs to be stripped and replated, and the plating production line needs to be shut down for inspection.

[0082] Embodiment 6

[0083] The embodiment of the present invention provides a method for detecting the quality of titanium-plated diamond abrasives. This detection method is basically the same as the detection method provided in Embodiment 4, and the main difference lies in:

[0084] In Step 1, the titanium-plated diamond abrasives are made into grinding wheels, and these grinding wheels are used for cutting steel bar workpieces. According to statistics, a grinding wheel of the same specification of copper-plated cubic boron nitride should be able to cut at least 150 workpieces, which is the qualified line of the grinding wheel. Among them, among the five batches of samples, the batch that cuts 152 workpieces is the sample closest to the statistical qualified line, and the deviation of other batches is greater than this batch. Therefore, in this embodiment, the samples of the batches of abrasives for which the grinding wheels are scrapped after cutting 152 workpieces among the five batches of samples extracted are reserved for subsequent detection of the qualified bonding strength standard value.

[0085] In Step 2, the bonding strength of the titanium-plated diamond abrasive samples determined in Step 1 and located at the qualified line is detected by using the bonding strength measurement method provided in Embodiment 2. In this embodiment, the bonding strength of the qualified batch of titanium-plated diamonds is determined and calibrated as the second laser power of 1000 mW. Therefore, the qualified bonding strength standard value of this specification of titanium-plated diamond abrasives is 1000 mW.

[0086] In Step 3, by using the bonding strength measurement method provided in Embodiment 2, the bonding strength of the titanium-plated diamond abrasives of the same specification on the production line is tested. When the titanium-plated layer on the second surface of the sample bursts at the second laser power of 800 mW, the bonding strength of the samples sampled from the production line is 800 mW, which is significantly lower than the qualified bonding strength standard value of 1000 mW. This batch of samples is unqualified. The product needs to be stripped and replated, and the plating production line needs to be shut down for inspection.

[0087] Therefore, the bonding measurement method provided by the embodiments of the present invention can use the laser power to calibrate the bonding strength of the coating of the electroplated abrasive. It can be detected as soon as the product comes off the production line, without waiting until the abrasive is made into grinding tools such as grinding wheels and sold to users and then waiting for user feedback on the bonding strength. It can quickly and quantitatively determine whether the electroplated abrasive on the production line is qualified, quickly and accurately detect the production process of the electroplating production line, and quickly discover abnormal production processes. In this way, it not only solves the problem that the bonding strength of electroplated abrasives cannot be detected, but also improves the process stability of the production line and the product yield.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific embodiments of the present invention or perform equivalent replacements for some technical features. Without departing from the spirit of the technical solutions of the present invention, they should all be covered by the scope of the technical solutions claimed in the present invention.

Claims

1. A method for measuring the coating adhesion of coated abrasives, comprising the steps: Step 1. Provide a coated abrasive grain, which is composed of an original abrasive and a coating layer that completely coats the surface of the original abrasive. The coated abrasive grain has a first surface and a second surface arranged face to face, and the coating layers on the first surface and the second surface form a complete wrap of the original abrasive; divide the first surface and the second surface by the maximum horizontal cross-section of the coated abrasive grain; wherein, The original abrasive refers to the original superhard abrasive without being treated by the coating process; the maximum horizontal cross-section refers to a horizontal plane when the coated abrasive particle is cut in the horizontal direction, and this horizontal plane coincides with the plane where the maximum linear diameter of the original abrasive is located in the horizontal direction, and the maximum linear diameter refers to the maximum radial length of the particle. Step 2: Remove the coating on the first surface of the coated abrasive particle to expose the first surface of the original abrasive, and the exposed part of the original abrasive is not damaged. Step 3: Use a second laser to irradiate downward from the first exposed and uncoated surface of the original abrasive and heat the original abrasive until the coating on the second surface bursts, and calibrate the coating adhesion of the coated abrasive under the laser heating conditions at this time. Use the tolerance degree of the stress caused by the thermal expansion of the original abrasive by the coating on the second surface of the original abrasive to calibrate the adhesion between the coating and the original abrasive.

2. The measuring method according to claim 1, characterized in that Step 2 includes: using a first laser to heat the coating on the first surface of the coated abrasive particle to vaporize the coating on the first surface and expose the first surface of the original abrasive.

3. The measuring method according to claim 2, characterized in that, Step 2 includes: the first laser is a high-power short-pulse laser, and the depth of its thermal effect is limited to the coating on the first surface, and the wavelength of the first laser is 240 - 460 nm.

4. The measuring method according to claim 2 or 3, characterized in that, Step 3 includes: using the second laser to vertically irradiate the first surface of the original abrasive, and making the irradiation area of the second laser on the first surface of the original abrasive cover the center of the maximum horizontal cross-section without exceeding the maximum horizontal cross-section and not being greater than 3 / 4 of the area of the maximum horizontal cross-section. Among them, the spot diameter of the second laser is 10 - 100 microns; adjust the heating conditions of the second laser until the coating on the second surface bursts, and calibrate the coating adhesion of the coated abrasive under the heating conditions of the second laser at this time.

5. The measurement method according to claim 4, characterized in that In Step 3, the second laser also selects a suitable wavelength and pulse width to heat the original abrasive in the direction perpendicular to the first surface of the original abrasive, and the focus of the second laser does not exceed half of the depth of the coated abrasive particle downward from the first surface of the original abrasive. Change the power of the second laser until the coating on the second surface bursts, and calibrate the coating adhesion of the coated abrasive under the power of the second laser at this time.

6. The measuring method according to claim 5, characterized in that The wavelength of the second laser is greater than the wavelength of the first laser, and the wavelength of the second laser is less than 700 nm.

7. The measuring method according to claim 5 or 6, characterized in that Step 3 includes: first filling the first surface of the original abrasive into a horizontal plane with a material having the same or similar refractive index as the original abrasive, and then using the second laser to irradiate and heat the original abrasive downward from the first surface of the original abrasive.

8. The measuring method according to claim 7, characterized in that The method for filling the first surface of the original abrasive into a horizontal plane includes: forming a planarization layer on the first surface of the original abrasive by the drop coating method, and the planarization layer has the same or similar refractive index as the original abrasive.

9. A method for detecting the quality of coated abrasives, comprising: Step 1: Select batches of coated abrasive grains whose grinding performance of the grinding tools made of the coated abrasive grains is at the qualified line according to the grinding performance of the grinding tools; Step 2: Use the bonding strength measurement method described in any one of claims 1 to 8 to measure the bonding strength of the coated abrasive grains at the qualified line selected in Step 1, and calibrate this bonding strength as the qualified bonding strength standard value of the coated abrasive grains; Step 3: First, use the same bonding strength measurement method as in Step 2 to detect the bonding strength of the coated abrasive grains of the same specification newly produced on the production line, and calibrate the detected value of the sample bonding strength; then compare the detected value of the sample bonding strength with the qualified bonding strength standard value to determine whether the coated abrasive grains of the same batch newly produced on the production line are qualified or unqualified.

10. The detection method according to claim 9, wherein Select multiple batches of coated abrasive grains, take a part of the same batch of sampled samples to make the grinding tools, and leave a part for subsequent measurement; determine the quality grades of different batches of coated abrasive grains according to the actual grinding performance of the grinding tools, and screen out the batches of coated abrasive grains whose grinding performance of the grinding tools is at the qualified line; Step 2 includes: using the bonding strength measurement method described in any one of claims 1 to 8, under the condition that the wavelength and pulse width of the second laser are the same, detect and determine the second laser power when the coating layer on the second surface of the coated abrasive grains at the qualified line selected in Step 1 bursts, and at this time calibrate the qualified bonding strength standard value with this second laser power; Step 3 includes: using the same method as in Step 2 to detect and determine the second laser power when the coating layer on the second surface of the coated abrasive grains of the same specification newly produced on the production line bursts, and calibrate the detected value of the sample bonding strength with this; if the detected value of the sample bonding strength is not less than the qualified bonding strength standard value, determine that the coated abrasive grains of the same batch newly produced on the production line are qualified; if the detected value of the sample bonding strength is less than the qualified bonding strength standard value, determine that the coated abrasive grains of the same batch newly produced on the production line are qualified.

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