Disclosure of Invention
The invention provides a grinding and polishing integrated composite grinding tool, which aims to solve the technical problems that in the prior art, free abrasive particle processing technology is low in processing efficiency, poor in-chip uniformity, low in abrasive utilization rate and large in waste liquid pollution, the surface of a workpiece is severely scratched by a solidified abrasive particle polishing technology, and free abrasive particle fine polishing still needs to be carried out after the solidified abrasive particle polishing.
The second object of the present invention is to provide a method for manufacturing the polishing integrated composite grinding tool.
A third object of the present invention is to provide a polishing method for a workpiece, wherein the workpiece is polished by using the polishing integrated composite abrasive tool as described above.
In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:
The grinding and polishing integrated composite grinding tool comprises a substrate layer and an abrasive layer, wherein a first abrasive and an organic composite microsphere pore-forming agent are fixedly connected in the abrasive layer, the organic composite microsphere pore-forming agent is a spherical or nearly spherical compound containing a second abrasive and a water-soluble adhesive, and the hardness of the second abrasive is less than or equal to the hardness of the first abrasive.
Preferably, the abrasive layer comprises, by mass, 30% -60% of a resin binder, 3% -20% of the first abrasive, 3% -35% of the organic composite microsphere pore-forming agent, 3% -10% of a filler and 0.2% -15% of an auxiliary agent.
Preferably, the particle size of the organic composite microsphere pore-forming agent is 20-90 μm.
Preferably, in the organic composite microsphere pore-forming agent, the mass percentage of the water-soluble adhesive is 2.5% -10%.
Preferably, the preparation method of the organic composite microsphere pore-forming agent is one of a centrifugal spray granulation method, a rolling particle method or an inverse microemulsion polymerization method.
Preferably, the water-soluble adhesive comprises at least one of cyclodextrin, dextrin, starch, hydroxymethyl cellulose, methyl cellulose, polyacrylic acid, polyacrylamide and polyvinyl alcohol.
Preferably, the second abrasive comprises at least one of alumina, silica, and ceria.
Preferably, the second abrasive has a mohs hardness of 6 to 9.
Preferably, the particle size of the second abrasive is 100-500nm.
Preferably, the first abrasive comprises at least one of diamond, silicon carbide, cubic boron nitride, zirconia, and corundum.
Preferably, the first abrasive has a mohs hardness of 7 to 10.
Preferably, the particle size of the first abrasive is 20-500nm.
Preferably, the median particle diameter of the second abrasive is not smaller than the median particle diameter of the first abrasive.
Preferably, the resin binder comprises at least one of unsaturated polyester, epoxy, polyurethane.
Preferably, the filler comprises one or more combinations of graphite, carbon black, carbon fiber staple, carbon nanotubes, calcium carbonate, calcium silicate.
Preferably, the auxiliary agent comprises at least one of an initiator, a curing agent and a dispersing agent.
The preparation method of the grinding and polishing integrated composite grinding tool comprises the following steps:
s1, mixing raw materials of an abrasive layer, then defoaming to obtain a mixture, and placing the mixture into a forming die;
s2, a matrix layer is applied to the surface of the non-grinding and polishing surface of the mixture, and the grinding and polishing integrated composite grinding tool is obtained through solidification; or firstly solidifying the mixture to obtain an abrasive layer, and then adhering the substrate layer on the surface of the non-polished surface of the abrasive layer to obtain the integrated composite grinding tool.
The grinding and polishing method for the workpiece adopts the grinding and polishing integrated composite grinding tool to grind and polish the workpiece.
Compared with the prior art, the invention has the beneficial effects that:
(1) The grinding and polishing integrated composite grinding tool provided by the invention has the advantages that the first grinding material and the organic composite microsphere pore-forming agent are fixedly connected in the grinding material layer, and in the process of processing a workpiece, the first grinding material serves as a fixedly connected grinding material to grind the workpiece and improve the material removal rate; the organic composite microsphere pore-forming agent on the surface layer meets water-based grinding fluid on the surface of the grinding tool in the process of processing a workpiece, the water-soluble adhesive is physically dissolved, an open pore structure can be formed on the surface of the grinding tool, the pore structure contains second grinding materials which are freely distributed, the organic composite microsphere pore-forming agent is used as the pore-forming agent, the chip containing space inside the grinding tool is improved, the hardness of a grinding tool matrix is reduced, thereby reducing the scratches on the surface of the workpiece and enhancing the self-sharpening property of the grinding tool, and free abrasive particle components are introduced into the composite grinding tool to play roles in polishing the workpiece and improving the surface quality of the material; the integrated processing of grinding and polishing can be synchronously realized, the scratches are less, the surface quality is good, the material removal rate is high, and the high processing efficiency and the good surface quality of the workpiece are both considered.
(2) The grinding and polishing integrated composite grinding tool provided by the invention is used for grinding and polishing the surface of a workpiece, and compared with the traditional free abrasive grain polishing technology, the grinding material consumption is small, and the pollution of waste liquid can be reduced; compared with the traditional fixed abrasive grain processing technology, the processed workpiece has less scratches and good surface quality, and no further fine polishing treatment is needed.
Detailed Description
The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and detailed description, but it will be understood by those skilled in the art that the examples described below are some, but not all, examples of the present invention, and are intended to be illustrative of the present invention only and should not be construed as limiting the scope of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The first aspect of the invention provides an integrated grinding and polishing composite grinding tool, which comprises a substrate layer and an abrasive layer, wherein a first abrasive and an organic composite microsphere pore-forming agent are fixedly connected in the abrasive layer, the organic composite microsphere pore-forming agent is a spherical or nearly spherical compound containing a second abrasive and a water-soluble adhesive, and the hardness of the second abrasive is less than or equal to that of the first abrasive.
Aiming at the problems of low machining efficiency, low in-sheet uniformity, low abrasive utilization rate, large waste liquid pollution and serious surface scratch of a workpiece by a solidified abrasive particle machining technology in the prior art, the invention provides an integrated grinding and polishing composite grinding tool, which combines the advantages of solidified abrasive particle machining and free abrasive particle machining, can synchronously realize integrated grinding and polishing machining, has the advantages of less scratches, good surface quality, high material removal rate, and combines high machining efficiency and good workpiece surface quality.
The first abrasive and the organic composite microsphere pore-forming agent are fixedly arranged in the abrasive layer, as shown in fig. 3 and 5, the first abrasive is used as the fixedly-arranged abrasive to grind a workpiece and improve the material removal rate; the organic composite microsphere pore-forming agent on the surface layer of the composite grinding tool is contacted with water-based grinding fluid on the surface of the grinding tool in the processing process of the workpiece, the water-soluble adhesive is dissolved, an open pore structure can be formed on the surface of the grinding tool, the pore structure contains second abrasive materials which are freely distributed, the organic composite microsphere pore-forming agent is used as the pore-forming agent, the chip containing space inside the grinding tool is improved, the hardness of a matrix of the grinding tool is reduced, thereby reducing the scratches on the surface of the workpiece and enhancing the self-sharpening property of the grinding tool, and free abrasive particle components are released in situ in the working process of the composite grinding tool, so that the effects of polishing the workpiece and improving the surface quality of materials are achieved; thereby realizing the integrated processing of grinding and polishing.
The hardness of the first abrasive is controlled to be not less than that of the second abrasive, the first abrasive with relatively high hardness is selected as the fixed abrasive for grinding, and the second abrasive with relatively low hardness is selected as the free abrasive for polishing, so that higher grinding efficiency and surface quality of a workpiece can be ensured.
In some embodiments of the invention, the first abrasive and the organic composite microsphere pore former are uniformly distributed in the abrasive layer.
In some embodiments of the present invention, the abrasive layer comprises, by mass, 30% -60% of a resin binder, 3% -20% of a first abrasive, 3% -35% of an organic composite microsphere pore former, 3% -10% of a filler, and 0.2% -15% of an auxiliary agent.
The resin binder plays a role of fixing components such as a first abrasive, an organic composite microsphere pore-forming agent, a filler and the like, and is a key part for bearing and transmitting load and maintaining a polishing liquid environment in the composite grinding tool; the filler plays a role in enhancing the strength of the grinding layer, and the auxiliary agent mainly plays a role in initiating reaction or improving the crosslinking degree of the resin system or promoting the dispersion of components.
In some embodiments, typical but non-limiting, for example, the mass percent of resin binder in the abrasive layer can be any point value or range of values consisting of any two point values of 30%, 35%, 39%, 45%, 52%, 55%, 60%; the mass percent of the first abrasive can be any point value or a range value consisting of any two point values in 3%, 5%, 8%, 11%, 15%, 18% and 20%; the mass percentage of the organic composite microsphere pore-forming agent can be any point value or range value formed by any two point values in 3%, 5%, 10%, 15%, 20%, 25%, 28%, 31% and 35%; the mass percent of the filler can be any point value or range value formed by any two point values in 3%, 4%, 5%, 6%, 7%, 8%, 9% and 10%; the mass percent of the auxiliary agent can be any point value or range value formed by any two point values in 0.2%, 0.5%, 1%, 1.5%, 2%, 3%, 5%, 8%, 10%, 12% and 15%.
In some embodiments of the invention, the particle size of the organic composite microsphere pore former is 20-90 μm, e.g., can be any one or a range of values consisting of any two of 20 μm, 25 μm, 32 μm, 38 μm, 45 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm; the particle size of the organic composite microsphere pore-forming agent is too small, the screening equipment cannot accurately screen and control the particle size of the pore-forming agent during preparation, and in the process of processing a workpiece, the diameter of an open hole formed on the surface of a grinding tool is too small, so that the effects of polishing the workpiece, improving the surface quality of materials and enhancing the self-sharpening of the grinding tool are poor; the particle size of the organic microsphere pore-forming agent is too large, the structural stability of the grinding and polishing surface of the grinding tool is easy to be damaged, and the stability of the grinding and polishing effect cannot be ensured; therefore, the particle size range of the organic composite microsphere pore-forming agent needs to be reasonably controlled.
In some embodiments of the present invention, the mass percentage of the water-soluble binder in the organic composite microsphere pore former is 2.5% -10%, for example, may be any point value or range of values consisting of any two point values of 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%.
The content of the water-soluble adhesive in the organic composite microsphere pore-forming agent is too low, so that the second abrasive is easy to loosen and difficult to bond and aggregate into spheres; the content of the water-soluble adhesive is too high, so that the content of the second abrasive in the organic composite microsphere pore-forming agent is too low, the content of the second abrasive in the open holes in the composite grinding tool is too low, and the polishing effect of the free abrasive is poor, and therefore, the composition content of the organic composite microsphere pore-forming agent needs to be reasonably controlled.
As shown in fig. 1, in some embodiments of the present invention, the preparation method of the organic composite microsphere pore former is a centrifugal spray granulation method, comprising the steps of:
and (3) mixing and dispersing the second abrasive, the water-soluble adhesive and water to obtain aqueous dispersion with the mass fraction of the second abrasive being 10% -35%, and granulating and screening the aqueous dispersion by adopting a centrifugal spray granulation technology to obtain the abrasive.
In some embodiments of the invention, the means of mixing and dispersing in the preparation of the aqueous dispersion comprises shear dispersion and/or ultrasonic dispersion.
In some embodiments of the invention, the granulation is carried out in a centrifugal spray drying apparatus, the aqueous dispersion having a feed rate of 10-40ml/min, an inlet air temperature of 160-250℃and a centrifugal frequency of 200-400Hz.
In some embodiments, typically but not limited to, for example, the mass fraction of the second abrasive in the aqueous dispersion may be 10%, 15%, 20%, 25%, 30%, 35% of any point value or range of values consisting of any two point values; the liquid inlet speed of the aqueous dispersion can be any point value or range value formed by any two point values of 10ml/min, 20ml/min, 30ml/min and 40 ml/min; the air inlet temperature can be any point value or range value formed by any two point values in 160 ℃, 180 ℃,200 ℃, 210 ℃, 230 ℃ and 250 ℃; the centrifugation frequency may be any point value or range of values consisting of any two point values of 200Hz, 220Hz, 250Hz, 280Hz, 300Hz, 320Hz, 350Hz, 380Hz, 400 Hz.
The particle size of the organic composite microsphere pore-forming agent is larger (or smaller) due to the too high (or too low) concentration of the aqueous dispersion, the too high (or too small) liquid inlet speed and the too low (or too large) centrifugal frequency; the organic composite microsphere pore-forming agent with too low air inlet temperature cannot be dried completely, particles are easy to adhere to form blocks, the water-soluble adhesive is easy to be heated and decomposed due to too high air inlet temperature, the moisture is dried too fast, and the microspheres are broken and the shape of the pore-forming agent is damaged.
In other embodiments of the present invention, the organic composite microsphere pore formers may also be prepared by other methods such as a roll-to-roll process or an inverse microemulsion polymerization process.
In some embodiments of the present invention, the water-soluble binder comprises at least one of cyclodextrin, dextrin, starch, hydroxymethyl cellulose, methyl cellulose, polyacrylic acid, polyacrylamide, polyvinyl alcohol; the water-soluble adhesive plays a role in bonding the second abrasive in the preparation process of the organic composite microsphere pore-forming agent and the composite grinding tool.
In some embodiments of the invention, the second abrasive comprises at least one of alumina, silica, and ceria.
In some embodiments of the invention, the second abrasive has a mohs hardness of 6-9, for example, may be 6, 7, 8, or 9.
In some embodiments of the invention, the particle size of the second abrasive is 100-500nm, e.g., can be any point value or range of values consisting of any two point values of 100nm, 200nm, 300nm, 400nm, 500 nm.
In some embodiments of the present invention, the first abrasive comprises at least one of diamond, silicon carbide, cubic boron nitride, zirconia, corundum, wherein the diamond may be one or more combinations of single crystals, polycrystalline-like.
In some embodiments of the invention, the first abrasive has a mohs hardness of 7 to 10, for example, may be 7, 8, 9, or 10.
In some embodiments of the invention, the particle size of the first abrasive is 20-500nm, e.g., can be any point value or range of values consisting of any two point values of 20nm, 100nm, 200nm, 300nm, 400nm, 500 nm.
In some embodiments of the present invention, the median particle size of the second abrasive is not smaller than the median particle size of the first abrasive, which is advantageous for improving the polishing effect.
In some embodiments of the present invention, the resin binder includes at least one of an unsaturated polyester, an epoxy resin, a polyurethane, such as an epoxy acrylate, a polyethylene glycol acrylate, a polyurethane acrylate, a bisphenol a type epoxy resin, a bisphenol F type epoxy resin, a polyphenol type glycidyl ether epoxy resin, an aliphatic glycidyl ether epoxy resin, a glycidyl ester type epoxy resin, a polyester type polyurethane, a polyether type polyurethane, and the like.
In some embodiments of the present invention, the filler comprises one or more of graphite, carbon black, carbon fiber staple, carbon nanotubes, calcium carbonate, and calcium silicate, and the filler primarily serves to enhance the strength of the abrasive layer.
In some embodiments of the invention, the auxiliary agent comprises at least one of an initiator, a curing agent, and a dispersing agent; for example, the initiator may be azobisisobutyronitrile, dibenzoyl peroxide, tetraphenyl ethylene glycol, tetraphenyl succinonitrile, initiator 184, initiator 1173, initiator TPO or initiator 819, etc., which functions to initiate polymerization of the unsaturated polyester system; the curing agent can be aliphatic amine, aromatic amine, anhydride, isocyanate curing agent, polyhydroxy curing agent and the like, and plays a role in improving the crosslinking degree of a resin system and promoting the hardening and shaping of the grinding tool; the dispersing agent can be silane coupling agents KH550, KH560, KH570 and the like, and has the effects of improving the interfacial adhesion strength of the abrasive, the filler and the binding agent and promoting the uniform dispersion of the components.
In some embodiments of the invention, the matrix layer is a polymer sheet, for example, the matrix layer polymer may be carbon fiber, PET, PC, PMMA, PS, PI, epoxy, phenolic, polyurethane, rubber elastomer, or silicone elastomer.
As shown in fig. 2, a second aspect of the present invention provides a method for preparing a polishing integrated composite abrasive tool according to any one of the foregoing embodiments, including the steps of:
S1, mixing raw materials of an abrasive layer, then defoaming to obtain a mixture, and placing the mixture into a forming die with a specific shape;
S2, a matrix layer is applied to the surface of the non-grinding and polishing surface of the mixture, and the grinding and polishing integrated composite grinding tool is obtained through solidification; or firstly solidifying and demoulding the mixture to obtain an abrasive layer, and then adhering a matrix layer on the surface of the non-abrasive polishing surface of the abrasive layer to obtain the grinding and polishing integrated composite grinding tool.
The method provided by the invention has the advantages that the preparation process is simple, the prepared grinding and polishing integrated grinding tool can synchronously realize grinding and polishing integrated processing, the scratches are few, the surface quality is good, the material removal rate is high, the high processing efficiency and the good workpiece surface quality are both considered, and the advantages of free abrasive grain processing and consolidated abrasive grain processing are achieved.
In some embodiments of the invention, the curing means is photo-curing or thermal-curing.
In some embodiments of the invention, the uv light intensity of the photocuring is 500-1500mW/cm2, for example, may be any point value or range of values consisting of any two point values in 500mW/cm2、750mW/cm2、1000mW/cm2、1250mW/cm2、1500mW/cm2; the irradiation time is 20 to 120s, and may be, for example, any one point value or a range value composed of any two point values of 20s, 40s, 60s, 80s, 100s, 120 s.
In some embodiments of the invention, the substrate layers are bonded by an organic adhesive or double sided tape, and for abrasive tools comprising a plurality of different substrate layers, the different substrate layers may also be bonded by an organic adhesive or double sided tape.
In some embodiments of the present invention, the organic adhesive may be one or more of a hot melt type or a reactive type adhesive, for example, may be an epoxy adhesive, a polyurethane resin adhesive, a polyimide adhesive, an organic silicone adhesive, an acrylate adhesive, an acrylic adhesive, or the like.
In some embodiments of the present invention, the double-sided adhesive may be a resin type hot melt adhesive and/or a pressure sensitive adhesive.
According to the third aspect of the invention, the grinding and polishing integrated composite grinding tool is adopted to grind and polish the workpiece, the composite grinding tool is matched with water-based grinding fluid for use in the grinding and polishing process of the workpiece, the surface layer can form open holes containing second grinding materials, and the second grinding materials are released layer by layer from top to bottom along with the abrasion of the composite grinding tool.
In some embodiments of the present invention, the material of the workpiece to be processed may be a brittle and hard material difficult to process, such as silicon carbide, sapphire, ceramic or special glass.
In some specific embodiments of the invention, the water-based grinding fluid consists of water, an oxidant, a pH regulator, a catalyst and the like, wherein the water is a main substance of the grinding fluid, and plays roles in providing a liquid environment, dissolving pore-forming agents for pore forming and taking away the processing heat of a system in the processing process, and the mass fraction is 80% -98%; the oxidant is potassium permanganate, a softer oxidation reaction layer is formed on the surface of silicon carbide through oxidation reaction, the hardness of a processed workpiece is reduced, and the mass fraction is 1% -20%; the pH regulator is one or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, sodium hydroxide, potassium hydroxide, ammonia water, trimethyl ammonium hydroxide and the like, and has the functions of regulating the pH of the grinding fluid and regulating the oxidizing strength of potassium permanganate, and the pH of the system is generally between 4 and 6 or 9 and 11. The catalyst is manganese dioxide, which can be added in the process of preparing grinding fluid or provided by potassium permanganate oxidative decomposition products, and plays a role in catalyzing and adjusting the oxidation reaction rate, and the mass fraction of the manganese dioxide added is 0-2% in general.
As shown in fig. 4, the working principle of grinding and polishing the workpiece by adopting the above-mentioned grinding and polishing integrated composite grinding tool is as follows: in the grinding and polishing process, an oxidant in the water-based grinding fluid reacts with the surface of the workpiece under the action of a catalyst to generate a softened film layer with hardness smaller than that of the workpiece; meanwhile, the water-soluble adhesive in the organic microsphere pore-forming agent on the surface of the grinding tool is contacted and dissolved with water, and spherical or nearly spherical open holes are formed on the surface of the composite grinding tool, and free second grinding materials are contained in the holes; the first abrasive and the second abrasive in the abrasive layer play a role in mechanically removing the workpiece surface softening film layer. Wherein the first abrasive has a higher hardness than the second abrasive, and is mainly used for removing materials, and the second abrasive is mainly used for polishing.
Some embodiments of the invention are described in detail below in connection with specific examples. The starting materials used in the examples were commercially available unless otherwise specified.
In examples 1-8, the first abrasive d50 had a particle size of 200nm; the particle size of the organic composite microsphere pore-forming agent is 32-38 mu m, the organic composite microsphere pore-forming agent is obtained by adopting a centrifugal spray granulation method, and the particle size of the second abrasive d50 is 250nm. The median particle diameter of the filler used was 0.5. Mu.m; the unsaturated polyester is a mixture of prepolymer PEG400DA and a cross-linking agent, the epoxy resin is urethane modified epoxy resin UME308, and the polyurethane is a mixture of polyester polyurethane prepolymer and diethylenetriamine; wherein, the dispersing agent used in the unsaturated polyester system is KH570, the dispersing agent used in the epoxy resin system is KH560, and the dispersing agent used in the polyurethane system is KH550. The abrasive layer formulation compositions in examples 1-8 are shown in Table 1.
TABLE 1
Example 1
The formulation of the abrasive layer of this example is shown in Table 1, and the matrix layer is a PET sheet of 0.15mm thickness; the preparation method of the grinding and polishing integrated composite grinding tool comprises the following steps:
s1, uniformly mixing raw materials of a grinding material layer weighed according to the proportion of a table 1, defoaming and casting the raw materials into a forming die with a specific shape;
s2, placing the forming die in a blast oven phase, forming and curing in a thermal curing mode, wherein the curing program is 80 ℃/2h+100 ℃/2h+120 ℃/1h, curing and demolding to obtain an abrasive layer, and adhering a PET matrix layer on the non-abrasive surface of the abrasive layer through double faced adhesive tape to obtain the grinding and polishing integrated composite grinding tool.
Example 2
The formulation of the abrasive layer of this example is shown in Table 1, and the matrix layer is a PET sheet of 0.15mm thickness; the method for preparing the polishing integrated composite grinding tool is the same as in example 1.
Example 3
The formulation of the abrasive layer of this example is shown in Table 1, and the matrix layer is a polyurethane sheet 0.2mm thick; the preparation method of the grinding and polishing integrated composite grinding tool comprises the following steps:
s1, uniformly mixing raw materials of a grinding material layer weighed according to the proportion of a table 1, defoaming and casting the raw materials into a forming die with a specific shape;
S2, placing the forming die in a blast oven phase, forming and curing in a thermal curing mode, wherein the curing program is 80 ℃/2h+100 ℃/2h+140 ℃/2h, curing and demolding to obtain an abrasive layer, and adhering a polyurethane matrix layer on the non-abrasive surface of the abrasive layer through double-sided adhesive bonding to obtain the grinding and polishing integrated composite grinding tool.
Example 4
The formulation of the abrasive layer of this example is shown in Table 1, and the matrix layer is a polyurethane sheet 0.2mm thick; the method for preparing the polishing integrated composite grinding tool is the same as in example 3.
Example 5
The formulation of the abrasive layer of this example is shown in Table 1, and the base layer is a PC sheet of 0.15mm thickness; the preparation method of the grinding and polishing integrated composite grinding tool comprises the following steps:
s1, uniformly mixing raw materials of a grinding material layer weighed according to the proportion of a table 1, defoaming and casting the raw materials into a forming die with a specific shape;
S2, sticking the PC substrate layer sheet on the non-grinding and polishing surface of the molding material, defoaming again, placing the molding die in a blast oven phase, and performing program firing, curing and demoulding to obtain the grinding and polishing integrated composite grinding tool; wherein the curing procedure is 60 ℃/30min.
Example 6
The formulation of the abrasive layer of this example is shown in Table 1, and the base layer is a PC sheet of 0.15mm thickness; the method for preparing the polishing integrated composite grinding tool is the same as in example 5.
Example 7
The formulation of the abrasive layer of this example is shown in Table 1, and the matrix layer is a PET sheet of 0.15mm thickness; the preparation method of the grinding and polishing integrated composite grinding tool comprises the following steps:
s1, uniformly mixing raw materials of a grinding material layer weighed according to the proportion of a table 1, defoaming and casting the raw materials into a forming die with a specific shape;
S2, attaching the PET substrate layer sheet on the non-grinding and polishing surface of the molding material, defoaming again, curing by a photo-curing procedure, and demolding to obtain the grinding and polishing integrated composite grinding tool; wherein the photo-curing procedure was to irradiate for 80s with UV light having an intensity of 1000mW/cm2.
Example 8
The formulation of the abrasive layer of this example is shown in Table 1, and the matrix layer is a PET sheet of 0.15mm thickness; the method for preparing the polishing integrated composite grinding tool is the same as in example 7.
Comparative example 1
Comparative example 1 is similar to example 1, with the only difference that: the abrasive layer of comparative example 1 was not added with an organic composite microsphere pore-forming agent, and the proportions of the other components remained unchanged. The substrate layer used and the abrasive article were prepared in the same manner as in example 1.
Comparative example 2
Comparative example 2 is similar to example 3, with the only difference that: the grinding material layer of the comparative example 2 is not added with the organic composite microsphere pore-forming agent, and the proportion among other components is kept unchanged. The substrate layer used and the abrasive article were prepared in the same manner as in example 3.
Comparative example 3
Comparative example 3 is similar to example 5, with the only difference that: the grinding material layer of the comparative example 3 is not added with the organic composite microsphere pore-forming agent, and the proportion among other components is kept unchanged. The substrate layer used and the abrasive article were prepared in the same manner as in example 5.
Comparative example 4
Comparative example 4 is similar to example 1, with the only difference that: the alumina was replaced with an equivalent amount of dextrin (dextrin content 25wt% and alumina content 0) and the organic composite microsphere pore former of example 1 was replaced with paste microsphere containing no secondary abrasive, with the remaining conditions being the same as in example 1.
Comparative example 5
Comparative example 5 is similar to example 1, with the only difference that: the dextrin was replaced with an equal amount of alumina (dextrin content 0, alumina content 25 wt%) and a second abrasive was used in place of the organic composite microsphere pore former of example 1, with the remaining conditions being the same as in example 1.
Comparative example 6
Comparative example 6 is similar to example 1, with the only difference that: the dextrin (water-soluble binder) and alumina (second abrasive) were not granulated, the contents of each composition were the same as in example 1, and all the raw materials were directly mixed to prepare a composite abrasive, and the remaining process conditions were the same as in example 1.
Test examples
(1) Density, dry hardness and abrasive tool surface pore size testing
The density and dry hardness of the abrasive layers of the composite abrasive tools prepared in each example and each comparative example are respectively tested, and the pore diameter of the pore generated on the surface of the composite abrasive tool after the water-soluble adhesive in the organic composite microsphere pore-forming agent is dissolved is tested;
The density is measured by a density tester, and the liquid medium is kerosene;
The dry state hardness, the water-soluble adhesive in the organic microsphere pore-forming agent on the surface layer of the abrasive layer is not dissolved, and the hardness data is measured by a Shore C hardness meter;
Pore diameter, water-soluble adhesive in the organic composite microsphere pore-forming agent on the surface layer of the abrasive layer is dissolved in water and then dried, and the mixture is placed for 24 hours at room temperature; the pore diameter data were measured by SEM, and 20 pore diameter data were averaged over the same area.
The test results are shown in Table 2.
TABLE 2
| Density (g/cm3) | Dry hardness | Aperture (mum) |
| Example 1 | 1.59±0.10 | 82±4 | 34±5 |
| Example 2 | 1.70±0.10 | 79±4 | 33±4 |
| Example 3 | 1.43±0.11 | 74±3 | 34±4 |
| Example 4 | 1.39±0.10 | 78±4 | 33±5 |
| Example 5 | 1.62±0.12 | 72±5 | 33±4 |
| Example 6 | 1.66±0.11 | 69±4 | 34±5 |
| Example 7 | 1.60±0.13 | 72±5 | 34±3 |
| Example 8 | 1.59±0.10 | 68±3 | 33±4 |
| Comparative example 1 | 1.40±0.09 | 83±3 | / |
| Comparative example 2 | 1.30±0.10 | 76±4 | / |
| Comparative example 3 | 1.31±0.08 | 74±3 | / |
| Comparative example 4 | 1.17±0.09 | 79±5 | 33±6 |
| Comparative example 5 | 1.64±0.12 | 85±6 | / |
| Comparative example 6 | 1.62±0.16 | 81±4 | / |
As can be seen from the data in table 2, in the state that the inside of the dry abrasive layer is not perforated, the density of the abrasive layer is related to the composition ratio in the formulation, and in the case that the proportion of other components is not changed greatly, the density change of the abrasive layer of the abrasive added with the organic microsphere pore-forming agent is mainly affected by the types and contents of the components in the organic microsphere pore-forming agent, and as can be seen from example 1 and comparative example 6, in the case that the formulation composition is the same, the density difference between the composite abrasive prepared by adding the organic composite microsphere pore-forming agent and the abrasive layer prepared by mixing (not granulating) all the raw materials is not large.
From the comparison of example 1 and comparative example 1, example 3 and comparative example 2, and example 5 and comparative example 3, it is evident that the introduction of the organic composite microsphere pore-forming agent in the examples slightly reduces the hardness of the abrasive layer. As is evident from the comparison of examples 1 and examples 7 to 8, the hardness of the abrasive layer is significantly reduced by decreasing the proportion of the first abrasive and increasing the proportion of the organic composite microsphere pore former.
As can be seen from examples 1 to 8, the pore size of the surface of the abrasive layer is similar to that of the organic composite microsphere pore-forming agent, and the pore size of the surface of the abrasive layer obtained by pore-forming through the method is relatively uniform.
(2) Polishing performance test
The abrasive articles of examples 1,3, 5, 7, 8 and comparative examples 1-6 were used with a non-abrasive lapping slurry (KMnO4 slurry, ph=5.2-5.8) during lapping;
An example of free abrasive grain processing with a silica polishing liquid (ph=10.0 to 10.5, abrasive solid content 2 wt%) having a particle size of 250nm using SUBA800 as a polishing pad was taken as comparative example 7;
An example of free abrasive grain processing with SUBA800 as a polishing pad, in combination with a diamond polishing liquid (KMnO4 polishing liquid, ph=5.2 to 5.8, abrasive solid content 2 wt%) having a particle size of 200nm was taken as comparative example 8;
Test procedure as shown in fig. 6, the abrasive tools of examples 1, 3, 5, 7, 8 and comparative examples 1 to 8 were fixed on a turntable, 4-inch SiC single crystal wafers were fixed on a work-piece carrier (Si face down), and the polishing slurry was supplied through a liquid supply device, and other processing parameters are shown in table 3.
TABLE 3 Table 3
The average material removal rate, surface roughness, on-chip non-uniformity, average abrasive consumption rate during the polishing process of each example and each comparative example were tested as an index for evaluating the polishing effect;
The average material removal efficiency is calculated and obtained by a mass method;
The surface roughness is measured by a white light interferometer;
on-chip non-uniformity measurement: the thickness H was measured by uniformly selecting 17 points along two diameters perpendicular to each other from the edge of the wafer, through the center to the other edge, on the wafer processing surface. The calculation formula is as follows: non-uniformity= (Hmax-Hmin)/(2×H Mean value of) ×100%;
Average abrasive consumption rate calculation method: in examples 1,3, 5, 7,8 and comparative examples 1 to 6, average abrasive consumption rate = prepared abrasive consumption/abrasive life; in comparative examples 7 to 8, average abrasive consumption rate=slurry flow rate×slurry density×mass fraction of abrasive in the slurry.
The test results are shown in Table 4.
TABLE 4 Table 4
As can be seen from the data in table 4, the composite abrasive tools (examples 1, 3, 5) prepared in the examples of the present invention have higher average material removal rate and lower workpiece surface roughness, and can achieve both processing efficiency and surface quality, compared with the same formulation abrasive tools (comparative examples 1 to 3) without the organic composite microsphere pore-forming agent; as can be seen from the comparison of the example 1 and the comparative examples 4 to 6, the realization of the processing effect of the invention depends on the introduction of the organic composite microsphere pore-forming agent, and the same processing effect cannot be achieved by the simple mixing of part or all of the raw materials of the organic composite microsphere pore-forming agent in the abrasive layer; that is, even if the formulation composition is uniform, if the grinding tool is prepared by directly mixing the second abrasive and the water-soluble binder with other raw materials, the effect of the present invention cannot be achieved without previously granulating the second abrasive and the water-soluble binder to prepare the organic composite microsphere pore former. Compared with the free processing scheme (comparative examples 7-8) of the same processing abrasive particles, the method has higher material removal efficiency, the processed workpiece has better in-chip uniformity, and the method has lower abrasive particle consumption rate in unit time, thereby being beneficial to reducing the pollution of processing waste liquid to the environment.
As can be seen from a comparison of example 7 and example 8, decreasing the proportion of the first abrasive and increasing the proportion of the organic composite microsphere pore former, the average material removal efficiency of the workpiece decreases but is beneficial to improving the roughness of the workpiece surface.
As can be seen from the above discussion, the grinding and polishing integrated composite grinding tool prepared by the method can achieve the comprehensive effects of better material removal rate and surface quality, and can obviously improve the processing uniformity of silicon carbide workpieces and reduce the pollution of processing waste liquid to the environment.
While the invention has been illustrated and described with reference to specific embodiments, it is to be understood that the above embodiments are merely illustrative of the technical aspects of the invention and not restrictive thereof; those of ordinary skill in the art will appreciate that: modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some or all of the technical features thereof, without departing from the spirit and scope of the present invention; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions; it is therefore intended to cover in the appended claims all such alternatives and modifications as fall within the scope of the invention.