Hollow two-way pressing string bead cold pressing die structure

Abstract

The application provides a kind of hollow two-way pressing string bead cold-pressing die structure, including upper pressure head, core rod, female die, lower pressure head assembly, lower pressure head assembly includes lower pressure head sleeve, positioning core and height adjusting gasket, positioning core includes base and longitudinally fixed positioning core rod on base, positioning core rod passes through lower pressure head sleeve and forms lower pressure head mechanism with annular groove on top;Height adjusting gasket is padded between lower pressure head sleeve bottom end and base to adjust groove height;The diameter of positioning core rod is less than the longitudinal through hole of lower pressure head sleeve, and the positioning guide table with matching diameter is arranged on the rod body, and the outer wall of positioning guide table is processed flat position for powder falling.The hollow two-way pressing string bead cold-pressing die structure provided by the application can press string bead in two directions to press out diamond string bead compact with base exposed in two directions;And the exposed height of base bottom can be conveniently adjusted to better meet production requirements.

Description

Technical Field

[0001] This invention relates to the field of cold pressing mold technology for diamond beads, specifically to a cold pressing mold structure for hollow bidirectional pressing beads. Background Technology

[0002] Diamond wire saws, as flexible cutting tools, are widely used in the mining and shaping of stone. Diamond beads are the core component of diamond wire saws, and cold pressing is a crucial step in the production of diamond beads. Cold pressing is a process in which diamond-containing metal matrix powder is bonded to a base material through cold pressing to form a diamond bead blank. Cold pressing determines the final performance of the diamond wire saw and is the core process in the production of beaded wire saws.

[0003] Existing traditional cold pressing molds mainly include an upper pressing head 1, a lower pressing head 2, a mandrel 3, and a female mold 4. The upper pressing head 1 and the lower pressing head 2 are inserted into the female mold 4 from the upper and lower ends, respectively. The mandrel 3 and the lower pressing head 2 respectively limit the upper and lower ends of the bead base. When the upper pressing head 1 presses the powder downwards, the mandrel 3 slides into the core hole opened at the bottom of the upper pressing head 1, as shown in the attached figure. Figure 1 As shown in (a, b, c), the top of the lower pressure head 2 of this mold is flat except for the central positioning core. The cold-pressed beaded blank only has the top substrate exposed. During subsequent sintering, the bottom of the blank needs to be pressed again to expose the bottom substrate, forming a bidirectional substrate exposure structure. Since the sintering pressure head is a graphite pressure head while the substrate is steel, extrusion occurs between the pressure head and the substrate during sintering, easily causing deformation and damage to both, affecting the performance of the final beaded wire saw product. Furthermore, the graphite pressure head used in the sintering process needs frequent replacement, significantly increasing maintenance and operating costs and reducing production efficiency.

[0004] Based on the aforementioned shortcomings, a cold-pressing mold capable of bidirectional pressing is needed to press diamond bead blanks with bidirectional exposure at both ends of the matrix. Using this mold simplifies the subsequent sintering process, avoids the need for re-pressing with the graphite indenter, and improves production efficiency and product yield. Summary of the Invention

[0005] This invention proposes a cold-pressing mold structure for bidirectional pressing of beads, which can bidirectionally press the beads to produce diamond bead blanks with bidirectional exposed base material; and the exposed height of the base material bottom can be easily adjusted to better meet production needs.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention solves the above-mentioned problems through the following technical solutions:

[0007] A cold-pressing mold structure for hollow bidirectional pressing beads includes an upper pressing head, a mandrel, a female mold, and a lower pressing head assembly. The upper pressing head and the lower pressing head assembly are inserted into the female mold from the upper and lower ends, respectively. A core hole for inserting the mandrel is opened at the bottom end of the upper pressing head. The lower pressing head assembly includes a lower pressing head sleeve, a positioning core, and a height adjustment shim. The positioning core includes a base and a positioning core rod longitudinally fixed to the upper part of the base. The positioning core rod passes through a longitudinal through hole opened in the lower pressing head sleeve from bottom to top. A height adjustment shim is placed between the bottom end of the lower pressing head sleeve and the base. The diameter of the positioning core rod is smaller than the longitudinal through hole of the lower pressing head sleeve. A positioning guide platform with a diameter matching the longitudinal through hole is set on the rod body. Multiple flat positions are machined on the outer wall of the positioning guide platform for powder to fall. A positioning post is set at the middle of the top of the positioning core rod to fit through the bead base. The top surface of the positioning core rod is installed at a height lower than the top surface of the lower pressing head sleeve.

[0008] In the above scheme, the pressing head sleeve, positioning core, and height adjustment shims combine to form the pressing head structure. During installation, the top surface of the positioning core rod is lower than the top surface of the pressing head sleeve, forming an annular groove with the positioning column and pressing head sleeve to allow the bottom of the substrate to sink. The sinking of the substrate allows the pressed substrate to protrude from the compact below, forming a bottom exposed substrate structure. Combined with the top exposed substrate, this creates a bidirectional exposed substrate structure. By selecting height adjustment shims of different thicknesses, the relative height between the positioning core and the pressing head sleeve can be adjusted, thereby adjusting the depth of the annular groove, i.e., the substrate sinking height, to meet different substrate exposure height requirements.

[0009] During the bead-pressing process, extremely fine metal powder may be squeezed into the annular groove through the gap between the substrate and the pressing head. By setting the diameter of the positioning core rod smaller than that of the pressing head and machining a flattened section on the outer wall of the positioning guide platform, a hollow structure is created, allowing the powder entering the annular groove to fall down. This prevents the powder from accumulating and clumping in the groove, which could lead to mold failure and prevent the substrate from protruding properly. The annular groove uses an assembled structure of positioning core rod, positioning column, and pressing head, which not only facilitates adjustment of the substrate's exposed height but also makes it easy to disassemble and clean up the fallen powder, thus improving mold lifespan and ensuring production accuracy.

[0010] Furthermore, the outer wall of the positioning guide platform is machined with four flat positions arranged in a circumferential array, with the included angle between each flat position being 90 degrees.

[0011] Furthermore, the positioning guide platform is located at the top or bottom of the positioning core rod, and the positioning core rod, positioning guide platform, and positioning column are an integrated structure machined by a milling machine.

[0012] Furthermore, the positioning guide platform is located at the bottom end of the positioning core rod, and the longitudinal through hole is divided into an upper material dropping section and a lower guiding section. The diameter of the guiding section is larger than that of the material dropping section; the diameter of the positioning guide platform matches that of the guiding section.

[0013] Furthermore, the diameter of the positioning post matches the inner diameter of the bead base, and the inner diameter of the pressing head sleeve matches the outer diameter of the bead base.

[0014] Furthermore, the height adjustment shim is a metal ring made of the same material as the positioning core.

[0015] The present invention has the following beneficial effects:

[0016] 1. The pressing head in this solution adopts a modular structure. It consists of a pressing head sleeve, a positioning core, and a height adjustment shim, forming a pressing head with an annular groove at the top. During pressing, the bottom of the substrate sinks into the annular groove, ensuring that the substrate remains exposed at the bottom during the cold pressing process, achieving bidirectional cold pressing. Compared with existing methods, this invention achieves bidirectional bead pressing without changing the traditional semi-automatic cold pressing operation, improving cold pressing efficiency, reducing costs, and ensuring product performance.

[0017] 2. This design incorporates a gap between the positioning core and the pressing head sleeve. By using a positioning core rod with a diameter smaller than that of the pressing head sleeve and a flattened outer wall of the positioning guide platform to create a hollow structure, the powder and diamonds squeezed into the annular groove fall into the gap and do not accumulate in the annular groove. This reduces mold wear and replacement frequency, ensuring production quality.

[0018] 3. This solution adopts a modular design for the positioning core and the pressing head sleeve. The relative height of the positioning core and the pressing head sleeve can be adjusted by selecting height adjustment shims of different thicknesses, thereby adjusting the depth of the annular groove to meet different substrate exposure height requirements. The modular design allows for the replacement of different parts according to damage conditions, reducing mold wear. It features simple method, strong forward compatibility, and low cost. Attached Figure Description

[0019] Figure 1 (a) is a schematic diagram of the structure before pressing using an existing cold-pressing mold;

[0020] Figure 1 (b) is a schematic diagram of the structure after pressing with an existing cold-pressing mold;

[0021] Figure 1 (c) A cold-pressed beaded blank pressed using an existing cold-pressing die;

[0022] Figure 2 This is a schematic diagram of the cold pressing mold structure of Embodiment 1 of the present invention;

[0023] Figure 3 for Figure 2 Schematic diagram of the middle and lower pressure head assembly;

[0024] Figure 4 For along Figure 3 Sectional view of line AA in the middle;

[0025] Figure 5 A cold-pressed beaded compact with bidirectional exposure of the matrix;

[0026] Figure 6 This is a schematic diagram of the structure of the pressure head assembly in Embodiment 2 of the present invention;

[0027] Figure 7 In order to be in Figure 1 The diagram shows a structure with a sinkhole.

[0028] Part number markings: 1. Upper pressure head, 2. Lower pressure head, 3. Mandrel, 4. Female mold; 5. Lower pressure head sleeve, 51. Longitudinal through hole, 6. Positioning core, 61. Base, 62. Positioning core rod, 63. Positioning guide platform, 631. Flat part, 64. Positioning post, 7. Height adjustment shim.

[0029] 8. Beaded substrate, 9. Powder, 10. Sinking tank. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] Example 1

[0032] The cold-pressing mold structure for hollow bidirectional pressed beads described in this embodiment is shown in the attached figure. Figures 2-5 As shown, its main body includes an upper pressure head 1, a mandrel 3, a female mold 4, and a lower pressure head assembly. The upper pressure head 1 and the lower pressure head assembly are inserted into the female mold 4 from the upper and lower ends, respectively. The mandrel 3 and the lower pressure head assembly respectively limit the upper and lower ends of the bead base 8. When the upper pressure head 1 is inserted downward, the mandrel 3 slides into the core hole opened at the bottom of the upper pressure head 1. The upper pressure head 1, the lower pressure head assembly, the mandrel 3, and the female mold 4 form a bead forming cavity for pressing the cold-pressed bead blank.

[0033] As attached Figure 7 As shown, in the initial design phase, to achieve the sunken structure of the bead base 8, a sunken groove 10 was created at the top of the existing pressing head for the bottom of the bead base 8 to be inserted. This structure could press out diamond bead blanks with the base exposed in both directions. However, during further development, it was considered that extremely fine metal powder 9 would be squeezed into the sunken groove 10 from the gap between the bead base 8 and the pressing head 2 during the bead pressing process. Due to the high cold pressing pressure, the powder in the groove would clump together and become impossible to clean, causing the mold structure to fail and the base to be unable to protrude from the bottom, affecting bidirectional pressing. Furthermore, the exposed height of the base in the groove of this structure is inconvenient to adjust, and damage to any part requires replacement of the entire pressing head. Further improvements are needed to achieve a better bidirectional pressing effect.

[0034] Therefore, this embodiment improves the traditional pressure head into a pressure head assembly structure. (See attached diagram) Figure 3, 4 As shown, the pressure head assembly includes a pressure head sleeve 5, a positioning core 6, and a height adjustment shim 7. A longitudinal through hole 51 is formed in the center of the pressure head sleeve 5. The positioning core 6 includes a base 61, a positioning core rod 62, a positioning guide platform 63, and a positioning post 64. The positioning core rod 62 is longitudinally fixed to the top center of the base 61, and the positioning core 6 is mounted on the top center of the positioning core rod 62. The positioning guide platform 63 is coaxially disposed at the bottom of the positioning core rod 62. The positioning core rod 62, the positioning guide platform 62, and the positioning post 64 are an integral structure machined by a milling machine.

[0035] The positioning core rod 62 passes through the longitudinal through hole 51 of the pressing head sleeve 5 from bottom to top. During installation, the top surface of the positioning core rod 62 is lower than the top surface of the pressing head sleeve 5. The pressing head sleeve 5, the positioning core rod 62, and the positioning post 64 form an annular groove structure that allows the bottom of the base to sink into. The longitudinal through hole 51 of the pressing head sleeve 5 is divided into an upper material dropping section and a lower guiding section. The diameter of the guiding section is larger than that of the material dropping section, and the diameter of the positioning core rod 62 is smaller than that of the material dropping section. The diameter of the positioning guiding platform 63 matches that of the guiding section. The outer wall of the positioning guiding platform 63 is machined with four flat positions 631 arranged in a circumferential array, with an included angle of 90 degrees between each flat position 631.

[0036] The diameter of the positioning guide platform 63 matches that of the guiding section, which improves the connection stability between the positioning core rod 62 and the base 61, and can radially position the positioning core rod 62 to prevent wobbling. The diameter of the positioning core rod 62 is smaller than that of the pressing head sleeve 5, and the outer wall of the positioning guide platform 63 is machined with a flat part 631, which allows a hollow gap between the positioning core 6 and the pressing head sleeve 5, so that the diamond powder 8 squeezed into the annular groove can fall through the gap, avoiding accumulation in the groove and affecting the sinking height and flatness of the substrate.

[0037] The height adjustment shim 7 is installed between the bottom of the pressure head sleeve 5 and the base 61. By selecting height adjustment shims of different thicknesses, the relative height between the positioning core and the pressure head sleeve can be adjusted, thereby adjusting the depth of the annular groove and realizing the adjustment of the exposed height of the substrate. The height adjustment shim 5 uses a metal ring of the same material as the positioning core 6. The metal ring has high strength and can provide stable support for the pressure head sleeve 5.

[0038] In this embodiment, the outer diameter of the pressing head sleeve 5 is 12mm and the inner diameter is 7.2mm. The diameter of the guiding section of the longitudinal through hole 51 is 8mm. The diameter of the positioning core rod 62 is 6.2mm. The diameter of the positioning post 64 at the top of the positioning core rod 62 is 4.2mm. The width of the flat part 63 of the positioning guide platform 63 is 17.2mm. The height adjustment shim 7 is 1.5mm thick, so that the upper end face of the positioning core rod 62 is 1.5mm lower than the pressing head sleeve 5.

[0039] Using the hollow bidirectional pressing bead cold pressing mold structure described in this embodiment, the lower pressing head assembly is first assembled, and a suitable height adjustment shim 7 is placed on the base 61 of the positioning core 6 so that the positioning core rod 62 passes through the lower pressing head sleeve 5 from bottom to top, forming a lower pressing head structure with an annular groove at the top.

[0040] Then, the beaded base 8 is installed on the top of the lower pressure head 2, and the bottom of the beaded base 8 is fitted onto the positioning post 64. The bottom end of the beaded base 8 is sunk into the annular groove at the top of the lower pressure head assembly. Next, the lower pressure head assembly is placed into the female mold 4, and the mandrel 3 is installed on top of the beaded base 8. After completing the above steps, powder 9 is fed into the groove between the mandrel 3 and the female mold 4. The upper pressure head 1 will press the powder 9 down to the required height, and the powder 9 squeezed into the annular groove will fall through the structural gaps. After pressing, the top surface of the powder 9 is lower than the top surface of the beaded base 8, and the top of the beaded base 8 is exposed; the bottom surface of the powder 8 is higher than the bottom surface of the beaded base 8, and the bottom of the beaded base 8 is exposed. The structure of the beaded blank obtained by pressing is shown in the attached figure. Figure 5 As shown. After pressing, disassemble the lower pressing head assembly and clean up the fallen powder 9. Through the above steps, bidirectional pressing of beads can be achieved, resulting in diamond bead blanks with bidirectional exposure of the matrix, simplifying the subsequent sintering process and facilitating the production of high-quality beads.

[0041] Example 2

[0042] As attached Figure 6 As shown, unlike Embodiment 1, the positioning guide platform 63 is located at the top of the positioning core rod 62, and the diameter of the positioning guide platform 63 matches the blanking section above the longitudinal through hole 51. In this installation position of the positioning guide platform 63, the longitudinal through hole 51 can be a straight hole with only one diameter. The positioning guide platform 63, located at the top of the positioning core rod 62, is suitable for high-pressure pressing situations, preventing the positioning core rod 62 from bending due to excessive pressure. Of course, two positioning guide platforms, one at the top and one at the bottom, can also be used simultaneously according to the bead-stringing pressing requirements.

[0043] Through the above embodiments, bidirectional pressing of beads can be achieved without changing the traditional semi-automatic cold pressing operation, thereby improving cold pressing efficiency, reducing costs, and ensuring product performance.

[0044] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. Various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A cold-pressing mold structure for hollow bidirectional pressing beads, characterized in that: It includes an upper pressure head (1), a mandrel (3), a female mold (4) and a lower pressure head assembly. The upper pressure head (1) and the lower pressure head assembly are inserted into the female mold (4) from the upper and lower ends respectively. The bottom end of the upper pressure head (1) has a core hole for the mandrel (3) to be inserted. The pressing head assembly includes a pressing head sleeve (5), a positioning core (6), and a height adjustment shim (7); the positioning core (6) includes a base (61) and a positioning core rod (62) longitudinally fixed to the upper part of the base (61), the positioning core rod (62) passing through the longitudinal through hole (51) opened in the pressing head sleeve (5) from bottom to top; a height adjustment shim (7) is placed between the bottom end of the pressing head sleeve (5) and the base (61). The diameter of the positioning core rod (62) is smaller than the longitudinal through hole (51) of the pressure head sleeve (5). A positioning guide platform (63) with a diameter matching the longitudinal through hole (51) is provided on the rod body. Multiple flat positions (631) are machined on the outer wall of the positioning guide platform (63) for powder to fall. The positioning guide platform (63) is located at the top or bottom of the positioning core rod (62). The positioning core rod (62), the positioning guide platform (63) and the positioning column (64) are an integrated structure machined by a milling machine. The positioning core rod (62) is provided with a positioning post (64) at the top center, which is matched with the through hole of the bead base (8) for positioning. The top surface of the positioning core rod (62) is installed at a height lower than the top surface of the pressing head sleeve (5). The diameter of the positioning post (64) matches the inner diameter of the bead base (8), and the inner diameter of the pressing head sleeve (5) matches the outer diameter of the bead base (8). The pressing head sleeve (5), the positioning core rod (62), and the positioning post (64) form an annular groove structure into which the bottom of the bead base (8) can sink. The diameter of the positioning core rod (62) is smaller than that of the pressing head sleeve (5). The outer wall of the positioning guide platform (63) is machined with a flat part (631) so that there is a hollow gap between the positioning core rod (62) and the pressing head sleeve (5). The powder that is squeezed into the annular groove falls from the gap.

2. The cold pressing mold structure for hollow bidirectional pressed beads according to claim 1, characterized in that: The outer wall of the positioning guide platform (63) is machined with four flat positions (631) arranged in a circumferential array, and the included angle between each flat position (631) is 90 degrees.

3. The cold pressing mold structure for hollow bidirectional pressed beads according to claim 2, characterized in that: The positioning guide platform (63) is located at the bottom end of the positioning core rod (62). The longitudinal through hole (51) is divided into an upper material dropping section and a lower guide section. The diameter of the guide section is larger than that of the material dropping section. The diameter of the positioning guide platform (63) matches that of the guide section.

4. The cold pressing mold structure for hollow bidirectional pressed beads according to claim 1, characterized in that: The height adjustment pad (7) is a metal ring made of the same material as the positioning core (6).

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