Cold-pressing die and method for inner-outer layer structure diamond beads

Abstract

The application discloses a cold-pressing die and method for an inner-outer layer structure diamond bead. The cold-pressing die comprises an outer layer cold-pressing die for cold-pressing and molding an inner layer bead cold-pressing blank containing a layer of matrix structure, the outer layer cold-pressing die comprises an outer upper press head assembly, an outer female die and an outer lower press head assembly, the outer upper press head assembly comprises an outer upper press head sleeve and an elastic element and an outer upper core rod arranged in the outer upper press head sleeve, the elastic element is pre-tightened between an outer upper die seat and the outer upper core rod; the outer lower press head assembly comprises an outer lower press head sleeve and an outer lower core rod sleeved in the outer lower press head sleeve, an outer diameter of the inner layer bead cold-pressing blank is less than or equal to a diameter of the outer lower core rod; under the action of a cold-pressing device during pressing, the outer upper press head assembly drives the outer upper press head sleeve, the outer upper core rod and the inner layer bead cold-pressing blank to move downward and insert into the outer female die, in the process, outer layer matrix powder placed in a molding cavity is pressed on an outer peripheral surface of the inner layer bead cold-pressing blank to obtain the inner-outer layer structure diamond bead.

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 existing technology, cold pressing and sintering processes are usually used to make diamond beads. Cold pressing specifically involves fully mixing various metal powders of different weights (such as iron powder, cobalt powder, copper powder, etc.) and abrasives (diamond particles) 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 beaded matrix 5 respectively. When the upper press head 1 presses the body 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] Diamond beads cold-pressed using traditional cold-pressing dies have a single matrix structure layer in the radial direction of their circumferential cross-section. This structure consists of a base and a matrix layer disposed on the outer surface of the base. When the diameter of a bead with this structure decreases during the wire saw cutting process, the diamond concentration (i.e., volume ratio) remains unchanged due to the single-layer matrix. This increases the cutting force per diamond, while maintaining the same total cutting force. This increases the diamond wear rate and reduces the overall life of the wire saw.

[0005] To improve the wear resistance of diamond beads, diamond beads with multiple matrix layers designed on the surface of the base have emerged. For example, the utility model patent with publication number CN209533891U discloses a multi-layer electroplated diamond bead for a wire saw, comprising a bead base, a first diamond matrix layer electroplated on the outer surface of the bead base, and a second diamond matrix layer electroplated on the outer surface of the first diamond matrix layer. Another example is the invention patent with publication number CN114434649A, which discloses a multi-layer diamond bead, comprising a main base, at least one sub-base layer disposed on the surface of the main base, and a working layer disposed on the surface of both the main base and the sub-base, with a plurality of diamonds arranged in the working layer. However, these existing multi-layer diamond beads are manufactured by electroplating or brazing, not by cold pressing. After searching, the applicant has not found a cold pressing mold or 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 the inner layer bead cold pressed blank containing a layer of matrix structure obtained by cold pressing using a conventional cold pressing mold, so that diamond beads with an inner and outer layer structure having a multi-layer matrix structure and a diamond concentration in the outer layer 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 pressed blank having a 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 includes an outer upper pressure head sleeve mounted on the outer upper die base, an elastic element matching the inner diameter of the outer upper pressure head sleeve and an outer upper core rod are provided in 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 faces the outer lower core rod;

[0010] The outer lower pressure head assembly includes 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. 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 female mold; starting from the outer upper pressure head assembly entering the 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 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 to 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 producing diamond beads with inner and outer layer structures using the cold pressing mold is characterized by comprising the following steps:

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

[0017] 2) determining the formula of the outer carcass structure layer on the outer circumference of the inner beaded cold pressed billet, weighing the corresponding amount of components and mixing them evenly to obtain the outer 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 forming cavity with a certain accommodation space, and filling the outer layer carcass powder into the forming cavity;

[0019] 4) Place the inner 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 sleeve, control the outer upper pressure head assembly to move downward, drive the outer upper pressure head sleeve and the outer upper core rod as well as the inner layer beaded cold pressed blank to move downward and insert into the outer female mold, while the outer lower core rod moves downward and gradually withdraws from the female mold until it reaches the 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.

[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 structured diamond beads obtained by the cold pressing mold and method of the present invention are cold pressed blanks, which need to be sintered (performed according to conventional processes) before obtaining 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 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. This allows the resulting diamond beads to have different diamond concentrations in the radial direction of the circumferential cross-section. After the bead grinding diameter becomes smaller, the unit diamond force strength can be maintained, thereby increasing the bead life and improving the performance of the final product.

[0026] 2. The method of the present invention, without changing the original bead cold-pressing process, replaces the mold and uses the existing inner-layer cold-pressed bead blank containing only one carcass structure as the original matrix for secondary pressing. This achieves inner and outer double-layer pressing, resulting in a circumferential and radial diamond distribution density gradient in the cold-pressed beads, which is beneficial for improving product life and final product performance. Therefore, the method of the present invention is simple, easy to control, and has strong forward-looking process compatibility. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0030] Figure 4 The figure 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 Die for Diamond Beads with Inner and Outer Layer Structures

[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 respectively matched with the inner diameter of the outer female mold 8. 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.

[0036] The outer upper pressure head assembly includes an outer upper pressure head sleeve 9 mounted on an outer upper die base 12. An elastic element 11 and an outer upper core rod 10 are provided inside the outer upper pressure head sleeve 9. The diameters of the elastic element 11 and the outer upper core rod 10 both match the inner diameter of the outer upper pressure head sleeve 9. The upper end of the elastic element 11 is fixed to the upper die base at the top end of the outer upper pressure head sleeve 9, and its 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 directly opposite the outer lower core rod 14. Supported by the outer upper die base 12 and the elastic element 11, the outer upper core rod 10 extends out of the outer upper pressure head sleeve 9 and can slide relatively therein.

[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 disposed on the outer surface of the base body. 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. Therefore, the lower end of the returned outer upper core rod 10 extends out of the outer upper pressing head sleeve 9 and directly faces the inner-layer beaded cold-pressed blank placed on the outer lower core rod 14, and further, can directly face 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 outer layer cold pressing die, the elastic element 11 may be a compression spring, which is pre-tightened between the upper die base and the outer upper core rod 10 .

[0041] The cold pressing mold for the inner and outer layer structured 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 diamond beads with inner and outer layer structures

[0043] The method for producing diamond beads with inner and outer layer structures 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 the carcass structure;

[0045] 2) Determine the formula of the outer carcass structure layer on the outer circumference of the inner beaded cold pressed blank, weigh the corresponding amount of components and mix them evenly to obtain the outer 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 the predetermined position. During 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 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 upper pressure head assembly includes an outer upper pressure head sleeve (9) mounted on an outer upper die base (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 provided in 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 faces 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). 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. 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 exits the outer female mold (8); starting from the outer upper pressure head assembly entering the outer female mold (8), the outer layer body 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 body 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 structured 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 structured 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 diamond beads with inner and outer layer structures 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 carcass structure; 2) determining the formula of the outer carcass structure layer on the outer peripheral surface of the inner beaded cold pressed blank, weighing the corresponding amount of components and mixing them evenly to obtain the outer 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 structured diamond beads.

Images