Preparation method of abrasive disc

Abstract

The invention relates to a preparation method of an abrasive disc. The abrasive disc comprises a tray and abrasive cloth. The preparation method of the abrasive disc comprises the following steps that (1) glue injection is conducted, specifically, the bonding face of the tray faces upwards, and an adhesive is injected into the annular groove; (2) adhering the abrasive cloth: (2.1) placing the abrasive cloth on the mounting part, wherein the injection amount of the adhesive in the step (1) needs to meet the requirement that the adhesive can flow out of the annular groove and seep between the abrasive sheets of the abrasive cloth when being extruded by the abrasive cloth; (2.2) the shaft drives the tray to rotate, and an abutting plate capable of rotating along with the shaft abuts against the upper surface of the abrasive cloth; the outer edges of the abrasive sheets which exceed the outer edges of the mounting parts and are L2 in length abut against a rolling wheel on the side of the workbench, so that the outer edge of the whole abrasive cloth is smooth, and L2 is larger than L1; (3) overturning is conducted, specifically, the shaft, the abutting plate and the rolling wheel are moved away, and the abrasive disc is taken down from the base and overturned to be in the state that the bonding face faces downwards; and (4) drying. And secondary glue filling is not needed.

Description

Technical Field

[0001] The invention belongs to the technical field of grinding, polishing and surface treatment in an operation and transportation department, and specifically relates to a method for preparing an abrasive disc. The abrasive disc is suitable for grinding or polishing metal and non-metal surfaces. Background Art

[0002] Abrasive discs are widely used in the processing of industrial products, mainly for grinding and polishing. They are used in large-scale applications ranging from automobile, ship, and aviation manufacturing to small-scale applications such as jade grinding, heel grinding, stainless steel product manufacturing, and furniture manufacturing.

[0003] The grinding disc of the existing grinding and polishing tools is generally composed of a grinding cloth fixed on a base by glue or plastic buckles. The existing grinding disc, as shown in the "A Grinding Disc and Its Preparation Method" disclosed in the Chinese invention patent application with patent application number CN200810163675.2 (publication number CN101480788A), includes a tray and a grinding cloth. The tray includes a middle arched connecting part and a peripheral mounting part. The grinding cloth is bonded to the mounting part. The inner side of the tray is located between the connecting part and the mounting part and is provided with an annular convex rib, and the root of the grinding cloth is arranged around the outer side of the aforementioned convex rib, and is characterized in that a glue filling position is provided between the end of the convex rib and the root of the grinding cloth.

[0004] It can be seen from the patent that after the sandpaper is installed on the mounting part, glue needs to be added to ensure a firm connection between the sandpaper and the pallet. There are two methods for glue addition. One is to apply glue between the root of the sandpaper and the end of the rib for glue addition, and the other is to apply glue not only between the root of the sandpaper and the end of the rib for glue addition, but also on the back of the extended part of the sandpaper.

[0005] It can be seen that, in order to firmly stick the emery cloth to the pallet, the current grinding disc needs to be glued after the emery cloth is stuck to the mounting part, which is quite troublesome. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing a grinding disc in which the emery cloth does not need to be glued after being glued to a mounting part and the emery cloth can be firmly mounted on a tray in view of the current status of the prior art.

[0007] The technical solution adopted by the present invention to solve the above technical problems is: a method for preparing a grinding disc, the grinding disc comprises a tray and an abrasive cloth, the abrasive cloth comprises a plurality of abrasive discs, the tray comprises a connecting portion and a mounting portion connected to the connecting portion, the connecting portion is provided with a connecting hole for a shaft driving the tray to rotate to pass through, the inner side is close to the center line of the connecting hole, and the outer side is far from the center line of the connecting hole, the mounting portion is located on the outer side of the connecting portion, a plurality of abrasive discs are sequentially bonded to the mounting portion along the circumference of the mounting portion, and each of the abrasive discs partially extends out of the outer edge of the mounting portion, and the length of the abrasive disc exceeding the outer edge of the mounting portion is set to L1;

[0008] The invention is characterized in that: the end surface of the mounting portion forms a bonding surface for pasting the abrasive cloth, the bonding surface has an annular groove capable of accommodating the adhesive, and when the bonding surface faces downward, the outer wall surface of the annular groove is inclined downward from the inside to the outside to form an inclined surface;

[0009] The method for preparing the grinding disc comprises the following steps:

[0010] (1) Glue injection: Place the tray on the base on the workbench. The base can rotate relative to the workbench. The adhesive surface of the tray faces upwards. Inject adhesive into the annular groove.

[0011] (2) Adhesive cloth:

[0012] (2.1) placing the emery cloth on the mounting portion, the amount of adhesive injected in step (1) must be sufficient to flow out of the annular groove and seep into the gaps between the sand sheets of the emery cloth when squeezed by the emery cloth;

[0013] (2.2) The shaft drives the tray to rotate, and presses the upper surface of the sandpaper against the pressing plate that can rotate with the shaft. When the shaft drives the grinding disc to rotate, the base rotates under the friction of the grinding disc. At the same time, for the sanding disc with a length of L2 that exceeds the outer edge of the mounting portion, the outer edge of this part of the sanding disc contacts the roller on the side of the workbench, so that the outer edge of the sanding disc as a whole is flat, L2>L1;

[0014] (3) Turning over: Remove the shaft, pressure plate and roller, remove the abrasive disc from the base and turn it over to a state where the bonding surface faces downward. In this state, the adhesive flows along the inclined surface under the action of gravity and continues to seep between the abrasive discs.

[0015] (4) Drying.

[0016] In order to improve the drying efficiency, in step (4), the connection holes of the multiple grinding discs are penetrated on a rod body, and the top and bottom of the rod body respectively have limiting parts for pressing the uppermost grinding disc and the lowermost grinding disc, so that multiple grinding discs can be dried at the same time.

[0017] Preferably, in step (1) and step (2.1), the tray is in a state of rotation around the axis of the connecting hole driven by the shaft, so as to evenly inject glue into the annular groove along the circumference of the tray and place emery cloth on the mounting portion.

[0018] The roller can be moved manually to move it closer to or away from the grinding disc, but this is troublesome. Preferably, the roller is connected to a driving mechanism to move the roller toward or away from the grinding disc. The driving mechanism can be a motor, a cylinder, etc.

[0019] In the above solution, the annular groove is located between the inner side and the outer side of the emery cloth, and the adhesive in the annular groove can flow inward and outward under the pressure, thereby improving the connection stability between the emery cloth and the tray.

[0020] Preferably, the mounting portion is sequentially divided into a first portion and a second portion from the inside to the outside along the radial direction of the connecting hole, the thickness of the first portion is greater than the thickness of the second portion, and the annular groove is provided on the second portion. The provision of the annular groove can not only be used to accommodate the adhesive, but also make the thickness of the second portion thinner, that is, the thickness of the mounting portion becomes thinner from the inside to the outside, so that the heat dissipation of the grinding disc is good, so that the selection of adhesives is also much larger, and the existing adhesives that turn black when heated can also be used by the grinding disc of the present invention; in addition, this structural form of the grinding disc makes the mounting portion have a certain elasticity, so that the grinding disc feels better when used and does not give the user a hard feeling; and the mounting portion has a certain elasticity, which also makes the grinding disc better wrapped, for example, for an object to be polished with an irregular shape or a non-planar polishing surface, the elasticity of the mounting portion enables the grinding disc to better wrap the polishing surface, so as to better polish the object; in addition, the elastic mounting portion also makes the sandpaper have a certain flexibility, and the debris sandwiched between the sandpapers is easy to fall out, and will not turn black or affect the grinding effect.

[0021] In the above scheme, the connecting portion is in a truncated cone shape, including a planar portion and a cone extending obliquely from the periphery of the planar portion, the connecting hole is provided on the planar portion, and the mounting portion is annular and connected to the end of the cone through the annular body.

[0022] Preferably, the end surface of the annular body facing away from the bonding surface is arranged obliquely, so as to form a groove between the annular body and the connecting portion, so as to reduce materials and reduce costs, while ensuring the strength of the grinding disc.

[0023] Preferably, the outer edge of the end surface of the mounting portion facing away from the bonding surface is inclined from the inside to the outside in the direction of the bonding surface, so that the grinding disc can be extended into a smaller space to grind the surface to be ground, and has a wide range of usage scenarios.

[0024] Preferably, the plurality of sand sheets are stacked in sequence along the circumference of the mounting portion, and the sand sheets are tilted along the circumference of the tray, so that the mutual positioning effect between the sand sheets is good and they are not easy to separate.

[0025] Compared with the prior art, the advantages of the present invention are as follows: an annular groove is provided on the bonding surface of the mounting portion, and the annular groove can accommodate a large amount of adhesive. At the same time, the outer wall surface of the annular groove is an inclined surface, which is convenient for the adhesive to flow out. In the process of sticking the emery cloth on the mounting portion, the emery cloth will squeeze the adhesive in the annular groove so that the adhesive penetrates between the sand pieces of the emery cloth, so that the sand pieces are firmly bonded together; in addition, because the annular groove can accommodate a large amount of adhesive, the adhesive can seep out from the polishing surface of the emery cloth, that is, after the annular groove is provided, it is conducive to the excess adhesive to flow outward to realize back gluing.

[0026] In addition, in step (2.2) of the grinding sheet preparation method, when the tray is rotating, the outer edge of the grinding sheet with a length L2 exceeding the outer edge of the mounting portion collides with the roller beside the workbench. When this part of the grinding sheet collides with the roller, it will move toward the direction of the connecting portion, and finally the outer edge of each grinding sheet will extend the same length relative to the mounting portion. The length of the outer edge of each grinding sheet extending relative to the mounting portion is the set length L1, ensuring that the outer edge of the entire sand cloth is flat and the contour of the outer edge is circular.

[0027] In addition, during the process of the tray rotating and contacting the roller, the upper surface of the emery cloth is always pressed by the pressure plate. The pressure plate not only prevents the emery cloth from being displaced vertically by the roller, but also squeezes the emery cloth to make it firmly adhere to the bonding surface. The pressure of the pressure plate makes the emery cloth close to each other, and the adhesive will be squeezed and further seep between the emery cloths, thereby improving the tightness of the connection between the emery cloths.

[0028] The grinding disc of the present invention does not require a mold, secondary glue filling and back glue application, reduces the number of processes, greatly reduces the amount of glue used, and is conducive to reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the structure of a grinding disc according to an embodiment of the present invention;

[0030] Figure 2 for Figure 1 A schematic diagram of the structure in another direction;

[0031] Figure 3 for Figure 1 A cross-sectional view of

[0032] Figure 4 for Figure 1 A schematic diagram of the structure of the pallet;

[0033] Figure 5 for Figure 4 A cross-sectional view of

[0034] Figure 6 For multiple Figure 1 The schematic diagram of the structure in which the grinding disc is inserted into the rod body;

[0035] Figure 7 A schematic diagram of a tray of a grinding sheet according to an embodiment of the present invention being placed on a base;

[0036] Figure 8 Place the sandpaper on Figure 7 Schematic diagram on the tray;

[0037] Fig. 9 for Figure 8 Schematic diagram of the abrasive cloth and the roller in conflict. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described in detail below in conjunction with the embodiments of the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be understood that, in the description of the present invention patent, unless otherwise specified, "plurality" means two or more, and the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "top", "bottom", "front", "back", etc. are based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention patent and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention patent.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, a mechanical connection, or an adhesive connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0041] like Figures 1 to 5 As shown, the grinding sheet A of the preferred embodiment includes a tray 1 and an emery cloth 2. The tray 1 includes a connecting portion 11 and a mounting portion 12 connected to the connecting portion 11. The connecting portion 11 is provided with a connecting hole 111 for an axis driving the tray 1 to rotate to pass through. The mounting portion 12 is located on the outer side of the connecting portion 11, with the inner side being closer to the center line of the connecting hole 111 and the outer side being farther away from the center line of the connecting hole 111.

[0042] In this embodiment, the connecting portion 11 is in a truncated cone shape, including a planar portion 112 and a cone 113 extending obliquely from the periphery of the planar portion 112 . The connecting hole 111 is provided on the planar portion 112 . The mounting portion 12 is annular and connected to the end of the cone 113 through the annular body 13 .

[0043] The abrasive cloth 2 includes a plurality of abrasive sheets 21, which are bonded to the mounting portion 12. The abrasive sheets 21 are tilted along the circumference of the tray 1, and are stacked in sequence along the circumference of the mounting portion 12, so that the abrasive sheets 21 have a good mutual positioning effect and are not easy to separate.

[0044] The outer edge of each sand sheet 21 is located outside the mounting portion 12, so that the sand cloth 2 as a whole partially extends out of the outer edge of the mounting portion 12. In this way, the sand cloth 2 has a large grinding range, and when grinding, it has a certain elasticity and good coverage of the grinding surface.

[0045] The above is the prior art and will not be described in detail.

[0046] The end surface of the mounting portion 12 forms a bonding surface 121 for sticking the emery cloth 2. The bonding surface 121 has an annular groove 122 that can accommodate adhesive. The annular groove 122 extends circumferentially along the mounting portion 12. When the bonding surface 121 is facing downward, the outer wall surface of the annular groove 122 tilts downward from the inside to the outside to form an inclined surface 1221. The annular groove 122 is located between the inner side and the outer side of the emery cloth 2.

[0047] The end surface of the annular body 13 facing away from the bonding surface 121 is inclined, so that a groove 131 is formed between the annular body 13 and the connecting portion 11 to reduce materials and costs while ensuring the strength of the grinding disc.

[0048] In addition, the outer edge of the end surface of the mounting portion 12 facing away from the bonding surface 121 is inclined from the inside to the outside toward the bonding surface 121, so that the grinding disc can be extended into a smaller space to grind the grinding surface, which has a wide range of usage scenarios.

[0049] The method for preparing the grinding disc comprises the following steps:

[0050] (1) Glue injection: Figure 7 As shown, the tray 1 is placed on the base 41 on the workbench 4, the base 41 can rotate relative to the workbench 4, the bonding surface 121 of the tray 1 faces upward, and the adhesive is injected into the annular groove 122;

[0051] (2) Adhesive cloth 2:

[0052] (2.1) Figure 8As shown, the emery cloth 2 is placed on the mounting portion 12, and the amount of adhesive injected in step (1) must be sufficient to flow out of the annular groove 122 and seep between the sand sheets 21 of the emery cloth 2 when squeezed by the emery cloth 2; in other words, the emery cloth 2 will squeeze the adhesive so that the adhesive flows out of the annular groove 122, so as to achieve the bonding between the emery cloth 2 and the mounting portion 12, and the adhesive will penetrate between the sand sheets 21 of the emery cloth 2 so that the sand sheets 21 are firmly bonded together;

[0053] (2.2) Fig. 9 As shown, the shaft 5 drives the tray 1 to rotate, and presses the pressing plate 51 which can rotate with the shaft 5 on the upper surface of the sandpaper 2. When the shaft 5 drives the grinding disc to rotate, the base 41 rotates under the friction force of the grinding disc; at the same time, for the sanding disc 21 with a length of L2 exceeding the outer edge of the mounting portion 12, the outer edge of this part of the sanding disc 21 contacts the roller 6 on the side of the workbench 4, so that the outer edge of the sandpaper 2 as a whole is flat, and the length of the sanding disc 21 exceeding the outer edge of the mounting portion 12 is set to L1, L2>L1;

[0054] When the part of the sand piece 21 with a length L2 that exceeds the outer edge of the mounting portion 12 collides with the roller 6, it will move toward the direction of the connecting portion 11, and finally the outer edge of each sand piece 21 will extend the same length relative to the mounting portion 12. The length of the outer edge of each sand piece 21 extending relative to the mounting portion 12 is the set length L1, ensuring that the outer edge of the entire sand cloth 2 is flat and the contour of the outer edge is circular.

[0055] In addition, during the process of the tray 1 rotating and contacting the roller 6, the upper surface of the emery cloth 2 is always pressed by the pressure plate 51. The pressure plate 51 not only prevents the emery cloth 2 from being displaced vertically by the roller 6, but also squeezes the emery cloth 2 to make it firmly adhere to the bonding surface 121. The pressure of the pressure plate 6 makes the emery cloth 21 close to each other, and the adhesive will further seep between the emery cloth 21 under the pressure, thereby improving the connection tightness between the emery cloth 21.

[0056] (3) Turning over: the shaft 5, the pressure plate 51 and the roller 6 are removed, the abrasive disc is removed from the base 41 and turned over to a state where the bonding surface 121 faces downward. In this state, the adhesive flows along the inclined surface 1221 under the action of gravity and continues to seep between the abrasive discs 21. Because the annular groove 122 can accommodate a large amount of adhesive, the adhesive can seep out from the abrasive surface of the abrasive cloth 2.

[0057] The shaft 5 can be lifted up and down by a driving mechanism such as a motor. When the tray 1 needs to be driven to rotate, the shaft 5 is inserted into the connecting hole 111. When the tray does not need to rotate, the shaft 5 moves up and disengages from the connecting hole 111.

[0058] The roller 6 is also connected to the driving mechanism so that the roller 6 moves toward or away from the grinding disc. The driving mechanism can be a motor, a cylinder, etc. When the roller 6 is required to collide with the outer edge of the emery cloth 2, the roller 6 is close to the grinding disc, and when the roller 6 is not required to collide with the outer edge of the emery cloth 2, the roller 6 is away from the grinding disc.

[0059] The roller can adopt an existing structure as long as the cross section is circular and can rotate around a vertically extending axis. The roller will rotate around the vertically extending axis under the friction force of the grinding disc.

[0060] (4) Drying. In this step, in order to improve the drying efficiency, the connection holes 111 of the multiple grinding discs are provided on a rod body 3, and the top and bottom of the rod body 3 have limit parts 31 for pressing the uppermost grinding disc and the lowermost grinding disc, respectively. Figure 6 As shown, multiple grinding discs can be dried simultaneously. Specifically, the limiting portion 31 abuts against the tray 1 of the corresponding grinding disc.

[0061] In the above steps (1) and (2.1), the tray 1 is also driven by the shaft 5 to rotate around the axis of the connecting hole 111. In this way, the glue injection container is in a fixed position, that is, the glue can be evenly injected into the annular groove 122, and the slicer is in a fixed position, that is, the sanding sheet 21 can be evenly placed on the mounting portion 12.

[0062] In addition, the workbench 4 of the present embodiment is rotatable, and a plurality of bases 41 are provided on the workbench 4 at intervals along its circumference, and a tray 1 can be placed on each base 41. By rotating the workbench 4, the bases 41 are rotated to the glue injection container and the slicer in turn, so as to inject glue and place sand pieces 21 on the trays 1 on the bases 41 in turn.

[0063] It should be noted that step (1) and step (2.1) do not require the pressure plate 51, but step (2.2) requires the pressure plate 51. Alternatively, step (1) and step (2.1) may select the shaft 5 without the pressure plate 51, while step (2.2) may select the shaft 5 with the pressure plate 51.

[0064] In addition, in this embodiment, the mounting portion 12 is composed of a first portion 1211 and a second portion 1212 from the inside to the outside along the radial direction of the connecting hole 111 . The thickness of the first portion 1211 is greater than that of the second portion 1212 , and the annular groove 122 is provided on the second portion 1212 . The provision of the annular groove 122 can not only be used to accommodate the adhesive, but also makes the thickness of the second portion 1212 thinner, that is, the thickness of the mounting portion 12 becomes thinner from the inside to the outside, so that the heat dissipation of the grinding disc is good, and the choice of adhesive is also much larger. The existing adhesive that turns black when heated can also be used by the grinding disc of the present invention; in addition, this structural form of the grinding disc makes the mounting portion 12 have a certain elasticity, so that the grinding disc feels better when used and does not give the user a hard feeling; and the mounting portion 12 has a certain elasticity, which also makes the grinding disc have better wrapping properties. For example, for an object to be polished with an irregular shape or a polishing surface that is not a plane, the elasticity of the mounting portion 12 enables the grinding disc to better wrap the polishing surface so as to better polish the object; in addition, the elastic mounting portion 12 also makes the emery cloth 2 have a certain flexibility, and the debris sandwiched between the sanding sheets 21 is easy to fall out without turning black or affecting the grinding effect.

[0065] In this embodiment, the adhesive can be epoxy resin with an operating temperature of 80°~120°, or phenolic resin with an operating temperature of 170°~180°. The glue can be applied using a glue coating machine, and the emery cloth 2 can be adhered to the mounting portion 12 using a slicer. The curing and shaping can be done in an oven or under natural conditions in the air.

Claims

1. A method for preparing a grinding disc, the grinding disc comprising a tray (1) and an abrasive cloth (2), the abrasive cloth (2) comprising a plurality of abrasive discs (21), the tray (1) comprising a connecting portion (11) and a mounting portion (12) connected to the connecting portion (11), the connecting portion (11) being provided with a connecting hole (111) for a shaft (5) for driving the tray (1) to rotate to pass through, the inner side being close to the center line of the connecting hole (111) and the outer side being far from the center line of the connecting hole (111), the mounting portion (12) being located on the outer side of the connecting portion (11), the plurality of abrasive discs (21) being sequentially bonded to the mounting portion (12) along the circumference of the mounting portion (12), and each of the abrasive discs (21) partially extending out of the outer edge of the mounting portion (12), and the length of the abrasive disc (21) exceeding the outer edge of the mounting portion (12) being set as L1; Features: The end surface of the mounting portion (12) forms a bonding surface (121) for bonding the abrasive cloth (2), and the bonding surface (121) has an annular groove (122) capable of accommodating adhesive, and when the bonding surface (121) is facing downward, the outer wall surface of the annular groove (122) is inclined downward from the inside to the outside to form an inclined surface (1221); The method for preparing the grinding disc comprises the following steps: (1) Glue injection: placing the tray (1) on a base (41) on a workbench (4), the base (41) being rotatable relative to the workbench (4), with the adhesive surface (121) of the tray (1) facing upward, and injecting adhesive into the annular groove (122); (2) Adhesive cloth (2): (2.1) placing the emery cloth (2) on the mounting portion (12), wherein the amount of the adhesive injected in step (1) must be sufficient to allow the adhesive to flow out of the annular groove (122) and seep between the sand sheets (21) of the emery cloth (2) when squeezed by the emery cloth (2); (2.2) The shaft (5) drives the tray (1) to rotate, and presses a pressing plate (51) that can rotate with the shaft (5) on the upper surface of the sandpaper (2). When the shaft (5) drives the tray (1) to rotate, the base (41) rotates under the friction of the grinding disc. At the same time, for the sanding disc (21) whose length is L2 exceeding the outer edge of the mounting portion (12), the outer edge of this part of the sanding disc (21) contacts the roller (6) on the side of the workbench (4), so that the outer edge of the sandpaper (2) as a whole is flat, and L2>L1. (3) Turning over: the shaft (5), the pressure plate (51) and the roller (6) are removed, the grinding disc is removed from the base (41) and turned over to a state where the bonding surface (121) faces downward. In this state, the adhesive flows along the inclined surface (1221) under the action of gravity and continues to flow between the sand discs (21); (4) Drying.

2. The preparation method according to claim 1, characterized in that: In the step (4), the connection holes (111) of the plurality of grinding plates are formed on a rod body (3), and the top and bottom of the rod body (3) respectively have limiting portions (31) for pressing against the grinding plate located at the top and the grinding plate located at the bottom.

3. The preparation method according to claim 1, characterized in that: In the step (1) and the step (2.1), the tray (1) is driven by the shaft (5) to rotate around the axis of the connecting hole (111).

4. The preparation method according to claim 1, characterized in that: The roller (6) is connected to the driving mechanism so that the roller (6) moves toward or away from the grinding plate.

5. The preparation method according to claim 1, characterized in that: The annular groove (122) is located between the inner side and the outer side of the abrasive cloth (2).

6. The preparation method according to any one of claims 1 to 5, characterized in that: The mounting portion (12) is composed of a first portion (1211) and a second portion (1212) from the inside to the outside along the radial direction of the connecting hole (111); the thickness of the first portion (1211) is greater than the thickness of the second portion (1212); and the annular groove (122) is provided on the second portion (1212).

7. The preparation method according to any one of claims 1 to 5, characterized in that: The connecting portion (11) is in the shape of a truncated cone and comprises a plane portion (112) and a cone (113) extending obliquely from the periphery of the plane portion (112); the connecting hole (111) is provided on the plane portion (112); the mounting portion (12) is in the shape of an annular ring and is connected to the end of the cone (113) via the annular body (13).

8. The preparation method according to claim 7, characterized in that: The end surface of the annular body (13) facing away from the bonding surface (121) is arranged at an angle, thereby forming a groove (131) between the annular body (13) and the connecting portion (11).

9. The preparation method according to any one of claims 1 to 5, characterized in that: The outer edge of the end surface of the mounting portion (12) facing away from the bonding surface (121) is inclined from the inside to the outside in a direction toward the bonding surface (121).

10. The preparation method according to any one of claims 1 to 5, characterized in that: A plurality of sand sheets (21) are stacked in sequence along the circumference of the mounting portion (12), and the sand sheets (21) are arranged obliquely along the circumference of the tray (1).

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