Combined graphite die for hot pressing sintering

Abstract

The utility model discloses a combined graphite die for hot pressing sintering, which comprises a positioning base plate connected with a lower lifting column of a hot pressing furnace. A lower die cavity is formed in the center of the lower top die in a penetrating manner; the lower bottom die is clamped at the bottom of the lower die cavity; a lower graphite base plate is laid at the bottom of the lower die cavity; flexible graphite paper is laid on the inner wall of the lower die cavity; an upper bottom die is fixedly connected to the lower pressing head, an upper top die is arranged on the upper bottom die, an upper die cavity is formed in the center of the upper top die in a penetrating mode, the upper bottom die is clamped to the bottom of the upper die cavity, an upper graphite base plate is laid at the bottom of the upper die cavity, flexible graphite paper is laid on the inner wall of the upper die cavity, an upper powder containing cavity is formed in the upper graphite base plate, and an upper pressing head is arranged on the upper powder containing cavity. The utility model solves the problems of low working area utilization rate, low plate yield after demoulding and low production efficiency of the existing hot pressing sintering mould.

Description

Technical Field

[0001] The utility model belongs to the technical field of hot pressing and sintering molds, and particularly relates to a hot pressing and sintering combined graphite mold. Background Art

[0002] Hot pressing is a sintering method that involves filling a mold with dry powder and then applying pressure and heating in either a uniaxial or biaxial direction, achieving simultaneous forming and sintering. The advantage of this method is that the simultaneous application of pressure and heating maintains the powder in a thermoplastic state, facilitating contact, diffusion, and flow and mass transfer between particles. Hot pressing reduces the sintering temperature and shortens the sintering time, thereby suppressing grain growth. The resulting product features fine grains, high density, and excellent mechanical properties. Furthermore, with the appropriate mold, hot pressing can also produce products with complex shapes and precise dimensions.

[0003] Common mold materials for hot pressing and sintering include graphite, copper oxide, and silicon carbide. Graphite is widely used in hot pressing and sintering molds due to its good thermal conductivity, low linear expansion coefficient, strong thermal stability and thermal shock resistance, good lubrication and wear resistance, and excellent machinability.

[0004] The existing hot pressing and sintering mold can only sinter one blank at a time. On the basis of meeting the design strength, the mold size only occupies less than half of the space of the sintering furnace working area. At the same time, the existing mold is likely to have powder leakage problems during hot pressing and sintering, causing the finished plate to stick to the mold after sintering, and the edges and corners of the plate to crack during demolding, reducing the yield rate; and the hot pressing and sintering process involves multiple steps such as heating, heat preservation, cooling, pressure increase, pressure holding, and pressure reduction. Although the forming and sintering processes can be carried out simultaneously, the entire process is still very time-consuming, especially when batch production is required. The time cost is particularly prominent and the production efficiency is low. Utility Model Content

[0005] The utility model aims to provide a combined graphite die for hot pressing and sintering, which solves the problems of low working area utilization, low plate yield after demoulding and low production efficiency of existing hot pressing and sintering dies.

[0006] The technical solution adopted by the utility model is: a combined graphite mold for hot pressing and sintering, comprising a positioning pad, which is connected to a lifting column under a hot pressing furnace; a lower bottom mold is fixedly connected to the positioning pad, a lower top mold is arranged on the lower bottom mold, a lower mold cavity is penetrated through the center of the lower top mold, the bottom of the lower mold cavity is clamped with the lower bottom mold, a lower graphite pad is laid on the bottom of the lower mold cavity, a flexible graphite paper is laid on the inner wall of the lower mold cavity, a lower powder cavity is arranged on the lower graphite pad, a lower pressure head is arranged on the lower powder cavity, the lower pressure head is fixedly connected to the upper bottom mold, an upper top mold is arranged on the upper bottom mold, an upper mold cavity is penetrated through the center of the upper top mold, the bottom of the upper mold cavity is clamped with the upper bottom mold, an upper graphite pad is laid on the bottom of the upper mold cavity, flexible graphite paper is laid on the inner wall of the upper mold cavity, an upper powder cavity is arranged on the upper graphite pad, and an upper pressure head is arranged on the upper powder cavity.

[0007] The utility model is also characterized in that:

[0008] A pad positioning groove is provided on the lower surface of the positioning pad, and a pad positioning guide hole is provided on the upper surface of the positioning pad. The pad positioning guide hole and the pad positioning groove are arranged opposite to each other, and the bottom surface of the positioning pad is embedded in the lifting column under the hot pressing furnace along the pad positioning groove.

[0009] A lower bottom mold positioning guide column is set downward on the lower surface of the lower bottom mold, and the lower bottom mold positioning guide column is set opposite to the pad positioning guide hole. The lower bottom mold is inserted into the pad positioning guide hole along the lower bottom mold positioning guide column, and a lower bottom mold positioning boss is set upward on the upper surface of the lower bottom mold.

[0010] The bottom of the lower die cavity of the lower top die is clamped with the positioning boss of the lower bottom die, and the inner wall of the lower die cavity is gradually inclined outward from bottom to top.

[0011] A lower pressure head positioning guide hole is provided downward on the upper surface of the lower pressure head, and an upper bottom mold positioning guide column is provided upward on the lower surface of the upper bottom mold. The upper bottom mold positioning guide column is arranged opposite to the lower pressure head positioning guide hole. The upper bottom mold is inserted into the lower pressure head positioning guide hole along the upper bottom mold positioning guide column, and an upper bottom mold positioning boss is provided upward on the upper surface of the upper bottom mold.

[0012] The bottom of the upper die cavity of the upper top die is clamped with the positioning boss of the upper bottom die, and the inner wall of the upper die cavity is gradually inclined outward from bottom to top.

[0013] The lower bottom mold and the upper bottom mold have the same structural dimensions, the lower top mold and the upper top mold have the same structural dimensions, and the lower graphite pad and the upper graphite pad have the same structural dimensions.

[0014] The beneficial effects of the present invention are as follows: the combined graphite mold for hot pressing and sintering of the present invention has a compact structure and can simultaneously press and sinter two blanks in the working area, greatly improving space utilization and production efficiency. A circle of flexible graphite paper is laid out, and during hot pressing and sintering, the flexible graphite paper is respectively tightly attached to the mold, the pressure head and the blank, thereby sealing and preventing powder leakage. At the same time, due to the characteristics of graphite itself, the inner wall surfaces of the lower top mold and the upper top mold are inclined to facilitate demolding. During demolding, the flexible graphite paper can also play a lubricating role, preventing the material from adhering to the mold, thereby smoothly demolding and reducing the probability of edge collapse, thereby improving the yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of the hot-pressed and sintered combined graphite mold of the utility model;

[0016] Figure 2 yes Figure 1 Structural diagram of the AA section;

[0017] Figure 3 It is a cross-sectional schematic diagram of the hot-pressed sintered positioning pad of the utility model;

[0018] Figure 4 This is a cross-sectional schematic diagram of the lower bottom mold in the hot-pressed sintered combined graphite mold of the utility model;

[0019] Figure 5 This is a cross-sectional schematic diagram of the lower top mold in the hot-pressed sintered combined graphite mold of the utility model;

[0020] Figure 6 This is a schematic diagram of the lower pressure head in the hot-pressed sintered combined graphite die of the utility model;

[0021] Figure 7 This is a cross-sectional schematic diagram of the upper and lower molds in the hot-pressed sintered combined graphite mold of the utility model;

[0022] Figure 8 This is a cross-sectional schematic diagram of the upper die in the hot-pressed sintering composite graphite mold of the present invention. In the figure, 1. Positioning pad, 101. Pad positioning groove, 102. Pad positioning guide hole, 2. Lower base die, 201. Lower base die positioning guide post, 202. Lower base die positioning boss, 3. Lower top die, 4. Lower punch, 401. Lower punch positioning guide hole, 5. Upper base die, 501. Upper base die positioning guide post, 502. Upper base die positioning boss, 6. Upper die, 7. Upper punch, 8. Flexible graphite paper, 9. Lower graphite pad, 10. Upper graphite pad, 11. Lower powder chamber, 12. Upper powder chamber. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0024] The utility model is a hot-pressed sintered combined graphite mold, the structure of which is as follows Figure 1 and Figure 2 As shown, it includes a positioning pad 1, which is connected to the lifting column under the hot pressing furnace; the positioning pad 1 is fixedly connected to the lower bottom mold 2, and a lower top mold 3 is arranged on the lower bottom mold 2. The center of the lower top mold 3 runs through to open a lower mold cavity, and the bottom of the lower mold cavity is clamped with the lower bottom mold 2. The bottom of the lower mold cavity is paved with a lower graphite pad 9, and the inner wall of the lower mold cavity is paved with flexible graphite paper 8. A lower powder cavity 11 is arranged on the lower graphite pad 9, and a lower pressure head 4 is arranged on the lower powder cavity 11. The lower pressure head 4 is fixedly connected to the upper bottom mold 5, and an upper top mold 6 is arranged on the upper bottom mold 5. The center of the upper top mold 6 runs through to open an upper mold cavity, and the bottom of the upper mold cavity is clamped with the upper bottom mold 5. The upper graphite pad 10 is laid on the bottom of the upper mold cavity, and the inner wall of the upper mold cavity is paved with flexible graphite paper 8. An upper powder cavity 12 is arranged on the upper graphite pad 10, and an upper pressure head 7 is arranged on the upper powder cavity 12.

[0025] like Figure 3 As shown, the lower surface of the positioning pad 1 is provided with a pad positioning groove 101 upward, and the upper surface of the positioning pad 1 is provided with a pad positioning guide hole 102 downward. The pad positioning guide hole 102 and the pad positioning groove 101 are arranged opposite to each other, and the bottom surface of the positioning pad 1 is embedded in the lifting column under the hot pressing furnace along the pad positioning groove 101; Figure 4 As shown, the lower bottom mold 2 is provided with a lower bottom mold positioning guide column 201 downward on the lower surface, and the lower bottom mold positioning guide column 201 is arranged opposite to the pad positioning guide hole 102. The lower bottom mold 2 is inserted into the pad positioning guide hole 102 along the lower bottom mold positioning guide column 201, and the lower bottom mold 2 is provided with a lower bottom mold positioning boss 202 upward on the upper surface, as shown in FIG. Figure 5 As shown, the bottom of the lower mold cavity of the lower top mold 3 is clamped with the lower bottom mold positioning boss 202, and the inner wall of the lower mold cavity is gradually inclined outward from bottom to top.

[0026] like Figure 6 As shown, the upper surface of the pressing head 4 is provided with a pressing head positioning guide hole 401 downward, as shown in FIG. Figure 7 As shown, the lower surface of the upper bottom mold 5 is provided with an upper bottom mold positioning guide column 501, which is arranged opposite to the lower pressure head positioning guide hole 401. The upper bottom mold 5 is inserted into the lower pressure head positioning guide hole 401 along the upper bottom mold positioning guide column 501, and the upper surface of the upper bottom mold 5 is provided with an upper bottom mold positioning boss 502. Figure 8 As shown, the bottom of the upper mold cavity of the upper top mold 6 is clamped with the upper bottom mold positioning boss 502, and the inner wall of the upper mold cavity is gradually inclined outward from bottom to top.

[0027] The lower bottom mold 2 and the upper bottom mold 5 have the same structural dimensions and can be used interchangeably; the lower top mold 3 and the upper top mold 6 have the same structural dimensions and can be used interchangeably; the lower graphite pad 9 and the upper graphite pad 10 have the same structural dimensions and can be used interchangeably.

[0028] The working principle of the combined graphite mold for hot pressing and sintering of the present invention is that the lower top mold 3 is designed with an inclination; the lower top mold 3 is buckled into the lower bottom mold 2 along the positioning boss 202 of the lower bottom mold; the lower pressure head 4 is designed with a positioning guide hole 401; the upper bottom mold 5 is designed with a positioning guide column 501 and a positioning boss 502, and the upper bottom mold 5 is inserted into the positioning guide hole 401 along the positioning guide column 501; the upper top mold 6 is designed with an inclination; the upper top mold 6 is buckled into the upper bottom mold 5 along the positioning boss 502; flexible graphite paper 8 is arranged between the lower pressure head 4 and the inner wall of the lower top mold 3, and between the upper pressure head 7 and the inner wall of the upper top mold 6; the positioning pad 1 adopts a rectangular structure, and the working area size of the bidirectional hot pressing sintering furnace is φ350mm×300mm. In order to improve the utilization rate of the working area, improve production efficiency, and at the same time improve the yield rate of the plate after demoulding, a combined graphite mold for sintering two blanks can be formed at the same time.

[0029] Example 1

[0030] Two bags of molybdenum powder, each weighing 1.5 kg, were prepared for use. The positioning plate 1 was inserted into the lower lifting column of the sintering furnace along the plate positioning groove 101. The lower base mold 2 was placed horizontally, and the lower top mold 3 was lifted and snapped into the lower base mold 2 along the lower base mold positioning boss 202. The lower graphite plate 9 was then inserted. A circle of flexible graphite paper 8 was then placed on the inner wall of the lower base mold 2. The flexible graphite paper 8 was tightly attached to the wall of the lower powder chamber 11 and the lower graphite plate 9.

[0031] Pour 1.5kg of pre-prepared molybdenum powder into the lower powder loading chamber 11, shake it evenly, pre-press it flat, and then place it into the lower pressing head 4. Then, move the assembly into the sintering furnace working area, and insert the lower bottom mold positioning guide column 201 into the pad positioning guide hole 102 of the positioning pad 1. Next, place the upper bottom mold 5 horizontally, lift the upper top mold 6, and snap it into the upper bottom mold 5 along the positioning boss 502. Then, place the upper graphite pad 10. Then, arrange a circle of flexible graphite paper 8 on the wall of the upper powder loading chamber 12. The flexible graphite paper 8 is tightly attached to the wall of the upper powder loading chamber 12 and the upper graphite pad 10.

[0032] Pour another bag of 1.5kg heavy molybdenum powder prepared in advance into the upper powder loading chamber 12, shake it evenly, pre-press it flat, and then put it into the upper pressure head 7. Then move the assembly into the working area of the sintering furnace, and insert the upper bottom mold positioning guide column 501 into the positioning guide hole 401 of the lower pressure head 4. At this point, the powder loading, mold closing and furnace installation of the entire set of combined graphite mold are completed.

[0033] Example 2

[0034] Take two bags of molybdenum powder, each weighing 2kg, and insert the positioning plate 1 into the lower lifting column of the sintering furnace along the plate positioning groove 101. Place the lower base mold 2 horizontally, lift the lower top mold 3, and snap it into the lower base mold 2 along the positioning boss 202. Then, insert the lower graphite plate. Then, arrange a circle of flexible graphite paper 8 on the inner wall of the lower base mold. The flexible graphite paper 8 is tightly attached to the wall of the lower powder chamber 11 and the lower graphite plate 9.

[0035] Pour 2kg of pre-prepared molybdenum powder into the lower powder loading chamber 11, shake it evenly, pre-press it flat, and then place it into the lower pressure head 4. Then, move the assembly into the sintering furnace working area, and insert the lower bottom mold positioning guide column 201 into the pad positioning guide hole 102 of the positioning pad 1. Next, place the upper bottom mold 5 horizontally, lift the upper top mold 6, and snap it into the upper bottom mold 5 along the positioning boss 502. Then, place the upper graphite pad 10. Then, arrange a circle of flexible graphite paper 8 on the wall of the upper powder loading chamber 12. The flexible graphite paper 8 is tightly attached to the wall of the upper powder loading chamber 12 and the upper graphite pad 10.

[0036] Pour another 2kg bag of molybdenum powder prepared in advance into the upper powder loading chamber 12, shake it evenly, pre-press it flat, and then put it into the upper pressure head 7. Then move the assembly into the sintering furnace working area, and insert the upper bottom mold positioning guide column 501 into the positioning guide hole 401 of the lower pressure head 4. At this point, the powder loading, mold closing and furnace installation of the entire set of combined graphite mold are completed.

[0037] Example 3

[0038] Two bags of molybdenum trioxide powder, each weighing 1.5 kg, were prepared for use. The positioning plate 1 was inserted into the lower lifting column of the sintering furnace along the plate positioning groove 101. The lower base mold 2 was placed horizontally, and the lower top mold 3 was lifted and snapped into the lower base mold 2 along the positioning boss 202. The lower graphite plate was then inserted. A circle of flexible graphite paper 8 was then placed on the inner wall of the lower base mold. The flexible graphite paper 8 was tightly attached to the wall of the lower powder chamber 11 and the lower graphite plate 9.

[0039] Pour 1.5kg of pre-prepared molybdenum powder into the lower powder loading chamber 11, shake it evenly, pre-press it flat, and then place it into the lower pressing head 4. Then, move the assembly into the sintering furnace working area, and insert the lower bottom mold positioning guide column 201 into the pad positioning guide hole 102 of the positioning pad 1. Next, place the upper bottom mold 5 horizontally, lift the upper top mold 6, and snap it into the upper bottom mold 5 along the positioning boss 502. Then, place the upper graphite pad 10. Then, arrange a circle of flexible graphite paper 8 on the wall of the upper powder loading chamber 12. The flexible graphite paper 8 is tightly attached to the wall of the upper powder loading chamber 12 and the upper graphite pad 10.

[0040] Pour another 1.5kg bag of molybdenum trioxide powder prepared in advance into the upper powder loading chamber 12, shake it evenly, pre-press it flat, and then place it into the upper pressure head 7. Then, move the assembly into the working area of the sintering furnace, and insert the upper bottom mold positioning guide column 501 into the positioning guide hole 401 of the lower pressure head 4. At this point, the powder loading, mold closing and furnace installation of the entire set of combined graphite molds are completed.

[0041] The combined graphite mold for hot pressing and sintering of the utility model realizes the positioning and assembly of the mold through positioning grooves, positioning guide columns and positioning holes, thereby improving the installation and positioning effect of the workpiece, thereby improving the stability during hot pressing and sintering; the lower top mold 3 and the upper top mold 6 have the same structural dimensions, and the demoulding difficulty and the probability of edge collapse are reduced by setting the slope and arranging flexible graphite paper, thereby facilitating unloading after pressing.

Claims

1. A hot pressing and sintering combined graphite mold, characterized in that: The invention comprises a positioning pad (1), the positioning pad (1) is connected to the lifting column under the hot pressing furnace; the positioning pad (1) is fixedly connected to the lower bottom mold (2), the lower top mold (3) is provided on the lower bottom mold (2), the center of the lower top mold (3) is penetrated to open a lower mold cavity, the bottom of the lower mold cavity is clamped with the lower bottom mold (2), the bottom of the lower mold cavity is paved with a lower graphite pad (9), the inner wall of the lower mold cavity is paved with flexible graphite paper (8), the lower graphite pad (9) is provided with a lower powder cavity (11), and the lower powder cavity ( 11) is provided with a lower pressure head (4), the lower pressure head (4) is fixedly connected to the upper bottom mold (5), the upper top mold (6) is provided on the upper bottom mold (5), the center of the upper top mold (6) is penetrated to open an upper mold cavity, the bottom of the upper mold cavity is clamped with the upper bottom mold (5), the bottom of the upper mold cavity is paved with an upper graphite pad (10), the inner wall of the upper mold cavity is paved with flexible graphite paper (8), an upper powder cavity (12) is provided on the upper graphite pad (10), and an upper pressure head (7) is provided on the upper powder cavity (12).

2. A hot pressing and sintering combined graphite mold according to claim 1, characterized in that: The lower surface of the positioning pad (1) is provided with a pad positioning groove (101) pointing upwards, and the upper surface of the positioning pad (1) is provided with a pad positioning guide hole (102) pointing downwards. The pad positioning guide hole (102) and the pad positioning groove (101) are arranged opposite to each other, and the bottom surface of the positioning pad (1) is embedded in the lifting column under the hot pressing furnace along the pad positioning groove (101).

3. A hot pressing and sintering combined graphite mold according to claim 2, characterized in that: A lower bottom mold positioning guide column (201) is provided on the lower surface of the lower bottom mold (2) facing downwards, the lower bottom mold positioning guide column (201) is arranged opposite to the pad positioning guide hole (102), the lower bottom mold (2) is inserted into the pad positioning guide hole (102) along the lower bottom mold positioning guide column (201), and a lower bottom mold positioning boss (202) is provided on the upper surface of the lower bottom mold (2) facing upwards.

4. A hot pressing and sintering combined graphite mold according to claim 3, characterized in that: The bottom of the lower die cavity of the lower top die (3) is clamped with the lower bottom die positioning boss (202), and the inner wall of the lower die cavity is gradually inclined outward from bottom to top.

5. The hot pressing and sintering composite graphite mold according to claim 4, characterized in that: The upper surface of the lower pressure head (4) is provided with a lower pressure head positioning guide hole (401) facing downwards, and the lower surface of the upper bottom mold (5) is provided with an upper bottom mold positioning guide column (501) facing upwards. The upper bottom mold positioning guide column (501) is arranged opposite to the lower pressure head positioning guide hole (401), and the upper bottom mold (5) is inserted into the lower pressure head positioning guide hole (401) along the upper bottom mold positioning guide column (501). The upper surface of the upper bottom mold (5) is provided with an upper bottom mold positioning boss (502) facing upwards.

6. The hot pressing and sintering composite graphite mold according to claim 5, characterized in that: The bottom of the upper die cavity of the upper top die (6) is clamped with the upper bottom die positioning boss (502), and the inner wall of the upper die cavity is gradually inclined outward from bottom to top.

7. The hot pressing and sintering composite graphite mold according to claim 6, characterized in that: The lower bottom mold (2) and the upper bottom mold (5) have the same structural dimensions, the lower top mold (3) and the upper top mold (6) have the same structural dimensions, and the lower graphite pad (9) and the upper graphite pad (10) have the same structural dimensions.

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