Polycrystalline diamond sintering mold

Abstract

The utility model belongs to the field of diamond generation by applying an ultrahigh pressure method, and particularly relates to a polycrystalline diamond sintering mold. In order to solve the technical problems that a sintering grinding tool in the prior art does not improve the heat conduction efficiency of an insulating heat conduction layer, the utilization rate of heat at the two axial ends of the insulating heat conduction layer is low, and uniform distribution of a temperature field in a synthesis cavity is not facilitated, the utility model provides a polycrystalline diamond sintering mold. The sintering mold comprises a synthesis cavity, an insulating heat conduction layer defining the synthesis cavity and a heating layer located outside the insulating heat conduction layer, thinning parts are arranged at the two axial ends of the insulating heat conduction layer, and the heating layer comprises embedded parts corresponding to the thinning parts. The heating amount of the two axial ends of the synthesis cavity can be increased through the embedding parts, the utilization rate of heat of the two axial ends of the insulating heat conduction layer can be increased through the thinning parts, and therefore the temperature of the two ends of the synthesis cavity is increased, and temperature field distribution in the synthesis cavity is more uniform.

Description

Technical Field

[0001] The utility model belongs to the field of generating diamonds by applying an ultrahigh pressure method, in particular to a polycrystalline diamond sintering die. Background Art

[0002] Polycrystalline diamond is made of diamond or diamond plus carbide matrix sintered by high temperature and high pressure. Sintering can transform powdered materials into dense bodies. Sintering molds are required during the sintering process.

[0003] like Figure 1 As shown, a Chinese invention patent with authorization announcement number CN107362750B and authorization announcement date 2020.01.07 discloses a polycrystalline diamond composite sheet and a synthetic block thereof. The synthetic block is a sintering mold. The sintering mold includes a synthetic cavity 1 for accommodating the blank and an insulating thermally conductive layer 2 surrounding the synthetic cavity 1. The insulating thermally conductive layer 2 is composed of salt (NaCl). The salt can play a role in heat conduction and heat equalization, and the salt will not react with the blank in the synthetic cavity 1, nor will it contaminate the blank.

[0004] A heating layer is provided outside the insulating heat-conducting layer 2, and the heating layer includes a circumferential heating layer 3 located on the circumferential outside of the insulating heat-conducting layer 2 and end heating layers located at both axial ends of the insulating heat-conducting layer 2. The circumferential heating layer 3 is a circumferential metal heating layer with a relatively small heat generation, and the end heating layers include a central metal heating layer 4 with a relatively small heat generation and a graphite heating layer 5 located on the outer side of the outer circumferential surface of the central metal heating layer 4 and with a relatively large heat generation.

[0005] According to the heat transfer theory, when the synthesis chamber 1 is heated, the temperature in the middle of the synthesis chamber 1 is higher, and the temperature at the two axial ends of the synthesis chamber 1 is lower. In the above synthesis block, the heat generated at the two axial ends of the synthesis chamber 1 is increased by the graphite heating layer 5, so that the temperature field distribution inside the synthesis chamber 1 can be more uniform, which is beneficial to the synthesis of polycrystalline diamond and improves the quality of polycrystalline diamond products.

[0006] However, in the above-mentioned invention patent, in order to make the temperature field distribution in the synthesis chamber 1 more uniform, the technical means adopted is to set a graphite heating layer 5, and increase the heating value at both ends of the synthesis chamber 1 through the graphene heating layer 5, and the insulating heat-conducting layer 2 is not improved, that is, the thermal conductivity efficiency of the insulating heat-conducting layer 2 is not improved, resulting in low utilization rate of the heat generated by the heating layer and waste of energy; at the same time, the thermal conductivity efficiency of each part of the insulating heat-conducting layer 2 is the same, resulting in low utilization rate of the heat at the axial ends of the insulating heat-conducting layer 2, which is not conducive to the uniform distribution of the temperature field in the synthesis chamber 1. Utility Model Content

[0007] The utility model aims to provide a polycrystalline diamond sintering mold to solve the problem that in the prior art, in order to make the temperature field distribution in the synthesis cavity more uniform, the technical means adopted is to increase the heat generation at the axial ends of the synthesis cavity, but the thermal conductivity efficiency of the insulating heat-conducting layer is not improved, and the thermal conductivity efficiency of each part of the insulating heat-conducting layer is the same, resulting in low utilization rate of the heat at the axial ends of the insulating heat-conducting layer, which is not conducive to the uniform distribution of the temperature field in the synthesis cavity. At the same time, the utilization rate of the heat generated by the heating layer is low, wasting energy.

[0008] To achieve the above purpose, the technical solution of the polycrystalline diamond sintering mold provided by the utility model is:

[0009] A polycrystalline diamond sintering mold comprises a synthesis cavity for accommodating a blank, an insulating heat-conducting layer surrounding the synthesis cavity and a heating layer located outside the insulating heat-conducting layer, wherein both axial ends of the insulating heat-conducting layer are provided with thinning portions, and the heating layer comprises an embedding portion corresponding to the thinning portion.

[0010] Furthermore, the thinned portion extends along the axial direction of the insulating heat-conducting layer.

[0011] Furthermore, the embedded parts are connected end to end along the circumferential direction of the insulating heat-conducting layer.

[0012] Furthermore, the insulating heat-conducting layer includes a middle sleeve and end sleeves located at both axial ends of the middle sleeve, the inner diameters of the end sleeve and the middle sleeve are the same, and the outer diameter of the end sleeve is smaller than the outer diameter of the middle sleeve to form a thinning portion.

[0013] Furthermore, the thinned portion is located on the end surfaces at both axial ends of the insulating heat-conducting layer.

[0014] Furthermore, the thinned portion is located at a position close to the edge of the end surface of the insulating heat-conducting layer along the axial direction.

[0015] Furthermore, the thinned portions at the same end of the insulating heat-conducting layer are connected end to end.

[0016] Furthermore, the insulating heat-conducting layer includes end plates located at both axial ends of the insulating heat-conducting layer, and a groove is provided at one end of the end plate away from the synthesis cavity, and the end plate corresponding to the groove constitutes a thinning portion.

[0017] Furthermore, the end plate is a circular end plate, and the groove is a circular ring groove having the same center as the end plate.

[0018] Furthermore, the heating layer is made of graphite material.

[0019] The beneficial effects of the polycrystalline diamond sintering mold provided by the utility model are as follows: the utility model is an improved invention. The blank can be accommodated through the synthesis cavity, the blank in the synthesis cavity can be heated through the heating layer, and the temperature field distribution in the synthesis cavity can be made more uniform through the insulating heat-conducting layer, while avoiding the reaction between the blank and the heating layer; by arranging thinning parts at both axial ends of the insulating heat-conducting layer, and making the heating layer include corresponding embedded parts, on the one hand, the heat generation at both axial ends of the synthesis cavity can be increased through the embedded parts, which is conducive to making the temperature field distribution inside the synthesis cavity more uniform; on the other hand, by arranging the thinning parts, the thickness of the insulating heat-conducting layer between the embedded parts and the synthesis cavity can be reduced. When the thermal conductivity of the insulating heat-conducting layer is the same, the heat loss can be reduced by thinning the thickness of the insulating heat-conducting layer, that is, the thermal conductivity efficiency at both axial ends of the insulating heat-conducting layer can be improved, and the utilization rate of the heat at both axial ends of the insulating heat-conducting layer can be improved, thereby increasing the temperature at both ends of the synthesis cavity, making the temperature field distribution inside the synthesis cavity more uniform, and improving the quality of the final product. At the same time, the utilization rate of heat can be improved and energy can be saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a polycrystalline diamond sintering mold in the prior art;

[0021] Figure 2 It is a structural schematic diagram of a specific implementation method of the polycrystalline diamond sintering mold in the utility model;

[0022] Figure 3 It is a structural schematic diagram of another specific implementation manner of the polycrystalline diamond sintering mold in the utility model.

[0023] Description of reference numerals:

[0024] Figure 1 Middle: 1. Synthetic cavity; 2. Insulating heat-conducting layer; 3. Circumferential heating layer; 4. Central metal heating layer; 5. Graphite heating layer.

[0025] Figure 2-3 In the figure: 1. synthesis cavity; 2. insulating heat-conducting layer; 21. thinning portion; 3. heating layer; 31. embedding portion; 4. conductive element; 5. pressure head; 6. shell. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the embodiments.

[0027] The specific embodiment of the polycrystalline diamond sintering mold provided by the utility model is as follows:

[0028] The purpose of this embodiment is to provide a polycrystalline diamond sintered abrasive tool. By arranging thinning portions at both axial ends of the insulating heat-conducting layer and making the heating layer include corresponding embedded portions, on the one hand, the heating amount at the axial ends of the synthesis cavity can be increased, and on the other hand, the utilization rate of the heat at the axial ends of the synthesis cavity can be increased, and finally the temperature field distribution inside the synthesis cavity can be more uniform.

[0029] like Figure 2-3 As shown, as a specific embodiment, the polycrystalline diamond sintering mold includes a synthesis cavity 1 for accommodating the blank, an insulating heat-conducting layer 2 surrounding the synthesis cavity 1, and a heating layer 3 located outside the insulating heat-conducting layer 2, and thinning portions 21 are provided at both axial ends of the insulating heat-conducting layer 2, and the heating layer 3 includes an embedded portion 31 corresponding to the thinning portion 21.

[0030] Specifically, Figure 2 As shown, the polycrystalline diamond sintering mold also includes a shell 6, which is provided with a mounting through hole, and the heating layer 3, the synthesis cavity 1 and the insulating heat-conducting layer 2 are all located in the mounting through hole. The heating layer 3 is provided with a pressing head 5 that cooperates with the six-sided top press at both ends of the axial direction of the synthesis cavity 1, and a conductive element 4 electrically connected to the heating layer 3 is provided between the pressing head 5 and the heating layer 3. In this embodiment, the settings of the shell 6, the pressing head 5 and the conductive element 4 are all prior art, and any polycrystalline diamond sintering mold in the prior art can be referred to; the material of the insulating heat-conducting layer 2 is also prior art, and will not be repeated here.

[0031] The synthesis chamber 1 can accommodate the blank, the heating layer 3 can heat the blank in the synthesis chamber 1, and the insulating heat-conducting layer 2 can make the temperature field distribution in the synthesis chamber 1 more uniform, while avoiding the reaction between the blank and the heating layer 3; by arranging the thinning portions 21 at the axial ends of the insulating heat-conducting layer 2, and making the heating layer 3 include the corresponding embedded portions 31, on the one hand, the heat generation at the axial ends of the synthesis chamber 1 can be increased by the embedded portions 31, which is conducive to making the temperature field distribution inside the synthesis chamber 1 more uniform; on the other hand, by arranging the thinning portions 21, the thickness of the insulating heat-conducting layer 2 between the embedded portions 31 and the synthesis chamber 1 can be reduced. When the thermal conductivity of the insulating heat-conducting layer 2 is the same, the heat loss can be reduced by thinning the thickness of the insulating heat-conducting layer 2, that is, the thermal conductivity efficiency at the axial ends of the insulating heat-conducting layer 2 can be improved, and the utilization rate of the heat at the axial ends of the insulating heat-conducting layer 2 can be improved, thereby increasing the temperature at the two ends of the synthesis chamber 1, making the temperature field distribution inside the synthesis chamber 1 more uniform, and improving the quality of the final product. At the same time, it is possible to improve the heat utilization rate and save energy.

[0032] like Figure 2As shown, as a specific implementation, the thinning portion 21 extends along the axial direction of the insulating heat-conducting layer 2, and the embedded portion 31 is connected end to end along the circumferential direction of the insulating heat-conducting layer 2. Specifically, the insulating heat-conducting layer 2 includes a middle sleeve and end sleeves located at both ends of the middle sleeve in the axial direction, the end sleeve and the middle sleeve have the same inner diameter, and the outer diameter of the end sleeve is smaller than the outer diameter of the middle sleeve to form the thinning portion 21.

[0033] When the axial length of the synthetic cavity 1 is relatively long, the thinning portion 21 is extended along the axial direction of the insulating heat-conducting layer 2. Compared with the technical solution in which the thinning portion 21 is arranged at both axial ends of the insulating heat-conducting layer 2, the embedded portion 31 can be closer to the center of the synthetic cavity 1, which is beneficial to making the temperature field distribution inside the synthetic cavity 1 more uniform; the embedded portion 31 is connected end to end along the circumferential direction of the insulating heat-conducting layer 2, so that the synthetic cavity 1 corresponding to the embedded portion 31 can be heated in all aspects, which is beneficial to making the temperature field distribution inside the synthetic cavity 1 more uniform; the thinning portion 21 can be conveniently formed by using the intermediate sleeve and the end sleeve, and the structure is simple.

[0034] However, in other specific embodiments, the insulating heat-conducting layer 2 may also only include an insulating heat-conducting sleeve and insulating heat-conducting end plates located at the axial ends of the insulating heat-conducting sleeve, and grooves are provided on the outer peripheral surface of the insulating heat-conducting sleeve near the axial ends, and the insulating heat-conducting sleeve corresponding to the grooves constitutes a thinning portion 21, and the grooves may be two concentric annular grooves, and the two annular grooves are not connected; or, the groove is a "C"-shaped groove, or; the groove is three, four or more annular grooves spaced evenly on the same circumference. In this embodiment, the formation method of the thinning portion 21 is not limited.

[0035] like Figure 3 As shown, as another specific embodiment, the thinning portion 21 is located on the end faces at both axial ends of the insulating heat-conducting layer 2, the thinning portion 21 is located near the edge of the end face of the insulating heat-conducting layer 2 along the axial direction, and the thinning portions 21 located at the same end of the insulating heat-conducting layer 2 are connected end to end.

[0036] Specifically, the insulating thermal conductive layer 2 includes end plates located at both axial ends of the insulating thermal conductive layer 2. A groove is provided at the end of the end plate away from the synthetic cavity 1. The end plate corresponding to the groove constitutes a thinning portion 21. The end plate is a circular end plate, and the groove is a circular groove concentric with the end plate.

[0037] However, in other specific embodiments, the groove may also be provided at the center of the end plate, and the temperature field distribution at the end plate may be improved by increasing the ratio of the radius of the groove to the radius of the end plate; or, the end plate may also include a center plate and a flange connected to the outer peripheral surface of the center plate near one end of the insulating heat-conducting layer 2, and the thickness of the flange along the axial direction of the synthetic cavity 1 is less than the thickness of the center plate to form a thinning portion 21. Of course, in other specific embodiments, two, three, four or more annular grooves spaced apart on the same circumference may also be provided on the end plate, and the annular grooves are not interconnected; or, a rectangular groove connected end to end is provided on the end plate, and the rectangular groove includes two transverse grooves and two longitudinal grooves connected end to end and corresponding to the four sides of the rectangle. In this embodiment, the formation method of the thinning portion 21 is not limited.

[0038] like Figure 2-3 As shown, in order to further save energy, the heating layer 3 is made of graphite material. The resistance of graphite material is relatively large. When the power supply has internal resistance, compared with the metal heating layer with smaller resistance, according to the heat generation formula of resistance P = I 2 R shows that when the heating power is constant, the current corresponding to the graphite heating layer with larger resistance is smaller, that is, the heat generated by the internal resistance of the power supply is smaller, so the energy utilization rate is higher when the graphite heating layer is used, which is beneficial to saving energy. Of course, in other specific embodiments, the heating layer 3 can also be composed of metal materials such as molybdenum, niobium, zirconium, titanium or tantalum or other existing non-metallic materials. This part is the prior art and will not be repeated here.

[0039] At the same time, when the material of the heating layer 3 is constant, since the current passing through the heating layer 3 is constant, the calorific value of each part of the heating layer 3 is constant, and the effect of adjusting the temperature field in the synthesis chamber 1 can be achieved by changing the material of part of the heating layer 3. For example, in the Chinese invention patent with the authorization announcement number CN107362750B and the authorization announcement date of 2020.01.07, the heating layer 3 at both ends of the axial direction of the synthesis chamber 1 is set to a material with a larger calorific value. However, the calorific value of various materials is discontinuous, and the distribution of the temperature field in the synthesis chamber 1 cannot be well adjusted.

[0040] In this embodiment, the utilization rate of heat can be controlled by adjusting the thickness of the thinned portion 21. At the same time, the thickness of the thinned portion 21 can be continuously adjusted, so as to more conveniently adjust the distribution of the temperature field in the synthesis chamber 1. Of course, in other specific embodiments, after the heating layers 3 at both axial ends of the synthesis chamber 1 are set to materials with a large heat generation, the thickness of the thinned portion 21 can be adjusted, so as to make the temperature field distribution in the synthesis chamber 1 more uniform.

[0041] Finally, it should be noted that the above are only preferred embodiments of the utility model and are not intended to limit the utility model. Although the utility model is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A polycrystalline diamond sintering mold, comprising a synthesis cavity for accommodating a blank, an insulating heat-conducting layer surrounding the synthesis cavity, and a heating layer located outside the insulating heat-conducting layer, characterized in that: Both axial ends of the insulating heat-conducting layer are provided with thinning portions, and the heating layer comprises an embedding portion corresponding to the thinning portion.

2. The polycrystalline diamond sintering mold according to claim 1, characterized in that: The thinned portion extends along the axial direction of the insulating heat-conducting layer.

3. The polycrystalline diamond sintering mold according to claim 2, characterized in that: The embedded parts are connected end to end along the circumferential direction of the insulating heat-conducting layer.

4. The polycrystalline diamond sintering mold according to claim 3, characterized in that: The insulating heat-conducting layer comprises a middle sleeve and end sleeves located at two axial ends of the middle sleeve. The inner diameters of the end sleeve and the middle sleeve are the same, and the outer diameter of the end sleeve is smaller than that of the middle sleeve to form a thinning portion.

5. The polycrystalline diamond sintering mold according to claim 1, characterized in that: The thinned portion is located on the end surfaces at both axial ends of the insulating heat-conducting layer.

6. The polycrystalline diamond sintering mold according to claim 5, characterized in that: The thinned portion is located at a position close to the edge of the end surface of the insulating heat-conducting layer along the axial direction.

7. The polycrystalline diamond sintering mold according to claim 6, characterized in that: The thinned portions at the same end of the insulating heat-conducting layer are connected end to end.

8. The polycrystalline diamond sintering mold according to any one of claims 5 to 7, characterized in that: The insulating heat-conducting layer comprises end plates located at two axial ends of the insulating heat-conducting layer. A groove is provided at one end of the end plate away from the synthesis cavity. The end plate corresponding to the groove forms a thinning portion.

9. The polycrystalline diamond sintering mold according to claim 8, characterized in that: The end plate is a circular end plate, and the groove is a circular ring groove having the same center as the end plate.

10. The polycrystalline diamond sintering mold according to any one of claims 1 to 7, characterized in that: The heating layer consists of graphite material.

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