Cold pressing die and method for diamond string beads with inner and outer layer structures

Abstract

The invention discloses a cold pressing die and method for diamond beads with inner and outer layer structures. The cold-pressing die comprises an outer-layer cold-pressing die for pressing and forming an inner-layer bead cold-pressed blank containing a layer of carcass structure, the outer-layer cold-pressing die comprises an outer upper pressing head assembly, an outer female die and an outer lower pressing head assembly, the outer upper pressing head assembly comprises an outer upper pressing head sleeve, an elastic element and an outer upper core rod, and the elastic element and the outer upper core rod are arranged in the outer upper pressing head sleeve. The elastic element is pre-tightened between the outer upper die holder and the outer upper core rod; the outer lower pressing head assembly comprises an outer lower pressing head sleeve and an outer lower core rod sleeved with the outer lower pressing head sleeve, and the outer diameter of the inner-layer bead cold-pressed blank is smaller than or equal to the diameter of the outer lower core rod; during pressing, under the action of cold pressing equipment, the outer upper pressing head assembly drives the outer upper pressing head sleeve, the outer upper core rod and the inner-layer bead cold-pressed blank to move downwards and be inserted into the outer female die, and in the process, outer-layer matrix powder placed in the forming cavity is pressed on the peripheral face of the inner-layer bead cold-pressed blank to obtain the diamond bead with the inner-layer structure and the outer-layer structure.

Description

Technical Field

[0001] The invention relates to a diamond wire saw, in particular to a cold pressing die and method for diamond beads with inner and outer layer structures. Background Art

[0002] At present, diamond wire saws have been widely used in stone processing, concrete reinforcement and bridge and road removal industries. With the promotion of applications, the demand for diamond wire saws has also grown rapidly.

[0003] Diamond beads are the core component of diamond wire saws. In the prior art, cold pressing and sintering processes are usually used to make diamond beads. Cold pressing specifically involves fully and evenly mixing various metal powders (such as iron powder, cobalt powder, copper powder, etc.) and abrasives (diamond particles) of different weights, and then cold pressing them together with a metal matrix in a mold to obtain a beaded blank. The existing traditional cold pressing mold mainly includes an upper press head 1, a lower press head 2, a core rod 3 and a female mold 4. The upper press head 1 and the lower press head 2 are respectively inserted into the female mold 4 from the upper and lower ends. The core rod 3 and the lower press head 2 limit the upper and lower ends of the bead matrix 5 respectively. When the upper press head 1 presses the carcass powder 6 downward, the core rod 3 slides into the core hole opened at the bottom of the upper press head 1, as shown in the attached figure. Figure 1 As shown in (a, b, c).

[0004] The diamond beads formed by cold pressing using a traditional cold pressing mold have only one carcass structure layer in the radial direction of the circumferential cross section, and the structure includes a matrix and a carcass structure layer arranged on the outer surface of the matrix. When the diameter of the beads with this structure decreases during the wire saw cutting process, since there is only one layer of the matrix, the diamond concentration (i.e., volume ratio) contained remains unchanged. Under the condition of the total cutting force remaining unchanged, the cutting force per unit diamond increases, which increases the diamond wear rate and reduces the overall life of the wire saw.

[0005] In order to improve the wear resistance of diamond beads, there are diamond beads with multiple matrix layers designed on the surface of the matrix. For example, the utility model patent with the announcement number CN209533891U discloses a multi-layer electroplated diamond bead for a rope saw, including a bead matrix, a first layer of diamond matrix electroplated on the outer surface of the bead matrix, and a second layer of diamond matrix electroplated on the outer surface of the first layer of diamond matrix. Another example is the invention patent with the publication number CN114434649A, which discloses a multi-layer diamond bead, including a main matrix, at least one layer of sub-matrix is ​​arranged on the surface of the main matrix, and working layers are arranged on the surfaces of the main matrix and the sub-matrix, and a number of diamonds are arranged in the working layer. However, these existing multi-layer diamond beads are made by electroplating or brazing, not by cold pressing. After searching, the applicant did not find a cold pressing mold and method for preparing multi-layer matrix structure beads using a cold pressing process. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a cold pressing mold and method for diamond beads with inner and outer layer structures. The cold pressing mold is used to cold press an inner layer bead cold pressed blank containing a layer of matrix structure obtained by cold pressing with a conventional cold pressing mold, so that diamond beads with inner and outer layer structures having a multi-layer matrix structure and a diamond concentration in the outer matrix being lower than that in the inner layer can be obtained.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A cold pressing die for diamond beads with inner and outer layer structures, comprising an outer layer cold pressing die for pressing and molding an inner layer bead cold pressing blank having a layer of matrix structure, wherein the outer layer cold pressing die comprises a coaxially arranged outer upper pressing head assembly, an outer female mold and an outer lower pressing head assembly, wherein the outer upper pressing head assembly and the outer lower pressing head assembly are respectively inserted into the outer female mold from the upper and lower ends, wherein:

[0009] The outer upper pressure head assembly comprises an outer upper pressure head sleeve mounted on the outer upper die seat, an elastic element and an outer upper core rod matching the inner diameter of the outer upper pressure head sleeve are arranged inside the outer upper pressure head sleeve, the upper end of the outer upper core rod acts on the elastic element that can return it downward, and the lower end of the returned outer upper core rod extends out of the outer upper pressure head sleeve and is directly opposite to the outer lower core rod;

[0010] The outer lower pressure head assembly comprises an outer lower pressure head sleeve and an outer lower core rod, the outer lower core rod is installed on the outer lower die base, and passes through the longitudinal through hole opened on the outer lower pressure head sleeve from bottom to top, and the diameter of the outer lower core rod matches the inner diameter of the longitudinal through hole;

[0011] The outer diameters of the outer upper pressure head sleeve and the outer diameters of the outer lower pressure head sleeve respectively match the inner diameters of the outer female mold, and the outer diameter of the inner layer beaded cold pressed blank is less than or equal to the diameter of the outer lower core rod;

[0012] During pressing, the inner layer beaded cold-pressed billet is placed on the upper end of the outer lower core rod. Under the action of the cold pressing equipment, the outer upper pressure head assembly first acts on the upper end of the inner layer beaded cold-pressed billet, and then drives the inner layer beaded cold-pressed billet to move downward and insert into the outer female mold. At the same time, the outer lower core rod also moves downward and gradually withdraws from the outer female mold. Starting from the outer upper pressure head assembly entering the outer female mold, the outer layer carcass powder filled in the molding cavity formed by the outer wall of the outer lower core rod, the upper end of the outer lower pressure head sleeve and the inner wall of the outer female mold is pressed to form an outer layer carcass structure layer on the outer peripheral surface of the inner layer beaded cold-pressed billet, thereby obtaining the inner and outer layer structure diamond beads.

[0013] Furthermore, the elastic element is a compression spring, the upper end of which is fixed on the upper die base, and the lower end of which is connected to the outer upper core rod.

[0014] Furthermore, the lower end of the returned outer upper core rod extends out of the outer upper pressing head sleeve and faces the inner layer beaded cold pressed blank placed on the outer lower core rod.

[0015] The method for making inner and outer layer structure diamond beads by using the cold pressing mold is characterized by comprising the following steps:

[0016] 1) obtaining an inner layer beaded cold pressed blank having a layer of carcass structure;

[0017] 2) determining the formula of the outer layer carcass structure layer on the outer peripheral surface of the inner layer beaded cold pressed blank, weighing the corresponding amount of components and mixing them evenly to obtain the outer layer carcass powder;

[0018] 3) controlling the outer pressing head cover to move downward to a predetermined position, so that the outer wall of the outer lower core rod, the upper end of the outer pressing head cover and the inner wall of the outer female mold form a molding cavity with a certain accommodation space, and filling the outer layer carcass powder into the molding cavity;

[0019] 4) placing the inner layer beaded cold pressed blank on the upper end of the outer lower core rod;

[0020] 5) Fix the outer female mold and the outer lower pressure head cover, control the outer upper pressure head assembly to move downward, drive the outer upper pressure head cover, the outer upper core rod and the inner layer beaded cold pressed blank to move downward and insert into the outer female mold, and at the same time, the outer lower core rod moves downward and gradually withdraws from the outer female mold until it reaches a predetermined position. In this process, the outer layer carcass powder placed in the molding cavity is pressed to form an outer carcass structure layer on the outer peripheral surface of the inner layer beaded cold pressed blank, thereby obtaining the inner and outer layer structure diamond beads.

[0021] In the method described in the present application, the formula of the outer carcass structure layer can be determined as needed. In order to maintain the unit diamond force strength, the concentration of diamonds in the outer carcass structure layer should be lower than the concentration of diamonds in the existing carcass structure on the inner beaded cold-pressed blank.

[0022] In the present application, the structure of the inner layer beaded cold pressed blank with a carcass structure includes a base and a carcass structure layer arranged on the outer surface of the base. The inner layer beaded cold pressed blank with a carcass structure can be obtained by using conventional cold pressing molds and cold pressing methods.

[0023] The inner and outer layer structure diamond beads obtained by the cold pressing mold and method of the present invention are cold pressed blanks, which need to be sintered (according to conventional processes) to obtain diamond beads.

[0024] Compared with the prior art, the present invention is characterized in that:

[0025] 1. A specially designed outer cold pressing mold is used to press and form the inner layer bead cold pressed blank containing only one layer of matrix structure obtained by conventional cold pressing. A matrix structure layer with a lower diamond concentration is pressed on the outer surface of the inner layer bead cold pressed blank with a higher diamond concentration, so that the obtained diamond beads have different diamond concentrations in the radial direction of the circumferential section. After the grinding diameter of the beads becomes smaller, the unit diamond force strength can be maintained, the bead life is increased, and the performance of the final product is improved.

[0026] 2. The method of the present invention does not change the original bead cold pressing process. By replacing the mold, the existing inner layer bead cold pressed blank containing only one layer of matrix structure is used as the original matrix for secondary pressing, so that the inner and outer double layers of the matrix can be pressed, so that the circumferential radial diamond distribution of the cold pressed beads has a density gradient, which is beneficial to improving the product life and final product performance. Therefore, the method of the present invention is simple and easy to control, and has the characteristics of strong process forward compatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of an existing traditional cold pressing mold; wherein, (a) is a schematic diagram of the structure of an existing traditional cold pressing mold before pressing, (b) is a schematic diagram of the structure of an existing traditional cold pressing mold after pressing, and (c) is a beaded cold pressed blank pressed by an existing traditional cold pressing mold (i.e., the inner layer beaded cold pressed blank described in the present application).

[0028] Figure 2 It is a structural schematic diagram of the cold pressing mold of the present invention when performing secondary pre-pressing on the inner layer beaded cold pressed blank.

[0029] Figure 3 It is a schematic structural diagram of the cold pressing mold of the present invention when performing secondary pressing and molding on the inner layer beaded cold pressed blank.

[0030] Figure 4 It is a schematic structural diagram of diamond beads with inner and outer layer structures obtained by cold pressing using the cold pressing mold of the present invention.

[0031] The numbers in the figure are:

[0032] 1 upper pressing head, 2 lower pressing head, 3 core rod, 4 female mold, 5 base, 6 carcass powder, 7 outer carcass powder, 8 outer female mold, 9 outer upper pressing head sleeve, 10 outer upper core rod, 11 elastic element, 12 outer upper mold base, 13 outer lower pressing head sleeve, 14 outer lower core rod, 15 outer lower mold base. DETAILED DESCRIPTION

[0033] In order to better explain the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0034] Example 1: Cold pressing mold for inner and outer layer structure diamond beads

[0035] like Figures 2-3 As shown, the cold pressing mold of the inner and outer layer structure diamond beads described in the present invention includes an outer layer cold pressing mold for pressing and molding the inner layer bead cold pressed blank containing a layer of matrix structure, and the outer layer cold pressing mold includes a coaxially arranged outer upper pressure head assembly, an outer female mold 8 and an outer lower pressure head assembly, the outer diameter of the outer upper pressure head sleeve 9 and the outer diameter of the outer lower pressure head sleeve 13 are matched with the inner diameter of the outer female mold 8 respectively, and the outer upper pressure head assembly and the outer lower pressure head assembly are respectively inserted into the outer female mold 8 from the upper and lower ends to limit the upper and lower ends of the inner layer bead cold pressed blank respectively.

[0036] The outer upper pressure head assembly includes an outer upper pressure head sleeve 9 mounted on an outer upper die seat 12, an elastic element 11 and an outer upper core rod 10 are arranged inside the outer upper pressure head sleeve 9, the diameter of the elastic element 11 and the diameter of the outer upper core rod 10 are matched with the inner diameter of the outer upper pressure head sleeve 9, the upper end of the elastic element 11 is fixed on the upper die seat at the top of the outer upper pressure head sleeve 9, and the lower end is connected to the upper end of the outer upper core rod 10; the lower end of the outer upper core rod 10 is opposite to the outer lower core rod 14. The outer upper core rod 10 extends out of the outer upper pressure head sleeve 9 under the support of the outer upper die seat 12 and the elastic element 11 and can slide relatively inside the outer upper pressure head sleeve 9.

[0037] The outer lower pressure head assembly includes an outer lower pressure head sleeve 13 and an outer lower core rod 14. The outer lower core rod 14 is installed on the outer lower die base 15, and passes through the longitudinal through hole opened on the outer lower pressure head sleeve 13 from bottom to top. The diameter of the outer lower core rod 14 matches the inner diameter of the longitudinal through hole. Under the action of the cold pressing equipment, the outer lower pressure head sleeve 13 and the outer lower core rod 14 can slide relative to each other.

[0038] The inner layer beaded cold pressed blank comprises a base body and a carcass structure layer arranged on the outer surface of the base body, and the outer diameter of the inner layer beaded cold pressed blank is less than or equal to the diameter of the outer lower core rod 14. During pressing, the inner layer beaded cold pressed blank is placed on the upper end of the outer lower core rod 14, so that the lower end of the returned outer upper core rod 10 extends out of the outer upper pressing head sleeve 9 and faces the inner layer beaded cold pressed blank placed on the outer lower core rod 14, and further faces the base body of the inner layer beaded cold pressed blank on the outer lower core rod 14.

[0039] When the above-mentioned outer layer cold pressing mold is used to press the inner layer beaded cold pressed blank, the inner layer beaded cold pressed blank is first placed on the upper end of the outer lower core rod 14. Under the action of the cold pressing equipment, the outer upper pressure head assembly first acts on the upper end of the inner layer beaded cold pressed blank, and then drives the inner layer beaded cold pressed blank to move downward and insert into the outer female mold 8. At the same time, the outer lower core rod 14 also moves downward and gradually withdraws from the outer female mold 8; starting from the lower end of the outer upper pressure head assembly entering the outer female mold 8, the outer layer carcass powder filled in the molding cavity formed by the outer wall of the outer lower core rod 14, the upper end of the outer lower pressure head sleeve 13 and the inner wall of the outer female mold 8 is pressed to form an outer layer carcass structure layer on the outer peripheral surface of the inner layer beaded cold pressed blank, thereby obtaining the inner and outer layer structure diamond beads.

[0040] In the above outer layer cold pressing mold, the elastic element 11 may specifically be a compression spring, which is pre-tightened between the upper mold base and the outer upper core rod 10 .

[0041] The cold pressing mold for the inner and outer layer structure diamond beads of the present invention further includes a conventional cold pressing mold for obtaining the inner layer bead cold pressed blank, such as Figure 1 shown.

[0042] Example 2: Method for making inner and outer layer structure diamond beads

[0043] The method for manufacturing inner and outer layer structure diamond beads using the cold pressing mold described in Example 1 comprises the following steps:

[0044] 1) Use conventional cold pressing mold to obtain Figure 1 (c) The structure shown contains a layer of inner beaded cold pressed blank of carcass structure;

[0045] 2) determining the formula of the outer layer carcass structure layer on the outer peripheral surface of the inner layer beaded cold pressed blank, weighing the corresponding amount of components and mixing them evenly to obtain the outer layer carcass powder 7;

[0046] 3) Controlling the outer pressing head cover 13 to move downward to a predetermined position, so that the outer wall of the outer lower core rod 14, the upper end of the outer pressing head cover 13 and the inner wall of the outer female mold 8 form a molding cavity with a certain accommodation space, and filling the outer layer carcass powder 7 into the molding cavity;

[0047] 4) placing the inner layer beaded cold pressed blank on the upper end of the outer lower core rod 14;

[0048] 5) Fix the outer female mold 8 and the outer lower pressure head cover 13, control the outer upper pressure head assembly to move downward, drive the outer upper pressure head cover 9 and the outer upper core rod 10 and the inner layer beaded cold pressed blank to move downward and insert into the outer female mold 8, and at the same time, the outer lower core rod 14 moves downward and gradually withdraws from the female mold 8 until it reaches a predetermined position. In this process, the outer layer carcass powder placed in the molding cavity is pressed to form an outer carcass structure layer on the outer peripheral surface of the inner layer beaded cold pressed blank, thereby obtaining the inner and outer layer structure diamond beads, such as Figure 4 shown.

Claims

1. A cold pressing die for diamond beads with inner and outer layer structures, comprising an outer layer cold pressing die for pressing and molding an inner layer bead cold pressing blank having a layer of matrix structure, wherein the outer layer cold pressing die comprises a coaxially arranged outer upper pressing head assembly, an outer female mold (8) and an outer lower pressing head assembly, wherein the outer upper pressing head assembly and the outer lower pressing head assembly are respectively inserted into the outer female mold (8) from the upper and lower ends ... and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the outer lower pressing head assembly and the The outer upper pressure head assembly comprises an outer upper pressure head sleeve (9) mounted on an outer upper die seat (12), an elastic element (11) matching the inner diameter of the outer upper pressure head sleeve (9) and an outer upper core rod (10) are arranged inside the outer upper pressure head sleeve (9), the upper end of the outer upper core rod (10) acts on the elastic element (11) which can return it downward, and the lower end of the returned outer upper core rod (10) extends out of the outer upper pressure head sleeve (9) and is directly opposite to the outer lower core rod (14); The outer lower pressure head assembly comprises an outer lower pressure head sleeve (13) and an outer lower core rod (14), wherein the outer lower core rod (14) is mounted on the outer lower die base (15) and passes through a longitudinal through hole provided on the outer lower pressure head sleeve (13) from bottom to top, and the diameter of the outer lower core rod (14) matches the inner diameter of the longitudinal through hole; The outer diameters of the outer upper pressure head sleeve (9) and the outer diameters of the outer lower pressure head sleeve (13) respectively match the inner diameters of the outer female mold (8), and the outer diameter of the inner layer beaded cold pressed blank is less than or equal to the diameter of the outer lower core rod (14); During pressing, the inner layer beaded cold pressed blank is placed on the upper end of the outer lower core rod (14). Under the action of the cold pressing equipment, the outer upper pressure head assembly first acts on the upper end of the inner layer beaded cold pressed blank, and then drives the inner layer beaded cold pressed blank to move downward and insert into the outer female mold (8). At the same time, the outer lower core rod (14) also moves downward and gradually withdraws from the outer female mold (8); starting from the outer upper pressure head assembly entering the outer female mold (8), the outer layer carcass powder filled in the molding cavity formed by the outer wall of the outer lower core rod (14), the upper end of the outer lower pressure head sleeve (13) and the inner wall of the outer female mold (8) is pressed to form an outer layer carcass structure layer on the outer peripheral surface of the inner layer beaded cold pressed blank, thereby obtaining the inner and outer layer structure diamond beads.

2. The cold pressing die for the inner and outer layer structure diamond beads according to claim 1, characterized in that: The elastic element (11) is a compression spring, the upper end of which is fixed on the upper die seat, and the lower end of which is connected to the outer upper core rod (10).

3. The cold pressing die for the inner and outer layer structure diamond beads according to claim 1, characterized in that: The lower end of the returned outer upper core rod (10) extends out of the outer upper pressing head sleeve (9) and faces the inner layer beaded cold pressed blank placed on the outer lower core rod (14).

4. A method for producing inner and outer layer structure diamond beads using the cold pressing mold according to claim 1, characterized in that: The following steps are involved: 1) obtaining an inner layer beaded cold pressed blank having a layer of carcass structure; 2) determining the formula of the outer layer carcass structure layer on the outer peripheral surface of the inner layer beaded cold pressed blank, weighing the corresponding amount of components and mixing them evenly to obtain the outer layer carcass powder (7); 3) controlling the outer lower pressing head cover (13) to move downward to a predetermined position, so that the outer wall of the outer lower core rod (14), the upper end of the outer lower pressing head cover (13) and the inner wall of the outer female mold (8) form a molding cavity with a certain accommodation space, and filling the outer layer carcass powder (7) into the molding cavity; 4) placing the inner layer beaded cold pressed blank on the upper end of the outer lower core rod (14); 5) Fix the outer female mold (8) and the outer lower pressure head sleeve (13), control the outer upper pressure head assembly to move downward, drive the outer upper pressure head sleeve (9) and the outer upper core rod (10) and the inner layer beaded cold pressed blank to move downward and insert into the outer female mold (8), and at the same time, the outer lower core rod (14) moves downward and gradually withdraws from the outer female mold (8) until it reaches a predetermined position. During this process, the outer layer carcass powder placed in the molding cavity is pressed to form an outer layer carcass structure layer on the outer peripheral surface of the inner layer beaded cold pressed blank, thereby obtaining the inner and outer layer structure diamond beads.

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