Pressing die of flat vulcanizing machine for laboratory

Abstract

The utility model relates to the technical field of press molds of press vulcanizers, in particular to a press mold of a press vulcanizer for a laboratory, which comprises an upper mold and a lower mold, a cavity is arranged in one surface of the upper mold, a lug boss is arranged in the cavity, and when the upper mold and the lower mold are assembled, the surface of the upper mold, which is provided with the cavity, is attached to the lower mold. The die further comprises an upper die vacuum groove, an upper die air exhaust hole and an upper die connecting hole, the upper die air exhaust hole is formed in the surface of the protruding part, the upper die vacuum groove is formed in the upper die and communicated with the cavity through the upper die air exhaust hole, and the upper die connecting hole is formed in the side face of the upper die and communicated with the upper die vacuum groove. According to the utility model, the mold cavity can be effectively and well exhausted, so that pits in a sample are avoided, and the test use effect is effectively improved.

Description

Technical Field

[0001] This utility model relates to the technical field of pressing molds for flat vulcanizing machines, and more specifically, to a pressing mold for a laboratory flat vulcanizing machine. Background Technology

[0002] In existing flat vulcanizing machine technologies, flat vulcanizing machines are generally used in conjunction with compression molds to complete the sample preparation requirements. However, various technologies on the market are mainly aimed at finished product processing, with less emphasis on laboratory testing equipment.

[0003] The existing laboratory flat vulcanizing molds, due to the characteristics of each component in the mixed material system such as melting temperature, decomposition temperature, boiling point, and water absorption, cannot achieve good venting when processing mixed materials (such as mixed materials with added color masterbatch or carbon black masterbatch). As a result, the products will have uneven mixing and incomplete venting, leading to pits in the samples and affecting the test results. Utility Model Content

[0004] The purpose of this invention is to overcome the problem that existing laboratory flat vulcanizing machine molds cannot achieve good venting, and to provide a laboratory flat vulcanizing machine pressing mold that can achieve sufficient venting during the pressing process of the flat vulcanizing machine.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0006] A pressing mold for a laboratory flat vulcanizing machine is provided, including an upper mold and a lower mold. A cavity is provided in one side of the upper mold, and a protrusion is provided in the cavity. When the upper mold and the lower mold are closed, the side of the upper mold with the cavity is in contact with the lower mold. The mold also includes an upper mold vacuum groove, an upper mold evacuation hole, and an upper mold connecting hole. The upper mold evacuation hole is located on the surface of the protrusion. The upper mold vacuum groove is located inside the upper mold and communicates with the cavity through the upper mold evacuation hole. The upper mold connecting hole is located on the side of the upper mold and communicates with the upper mold vacuum groove.

[0007] In the above-described process, the upper and lower molds are first placed in a preheated vulcanizing machine for preheating. After preheating, the upper mold is opened, and an appropriate amount of sample mixture or pre-milled sample strips or slices is poured into the cavity. The upper and lower molds are then closed, and the external vacuum pump is connected to the upper mold connection hole. The vacuum pump is started, and the appropriate evacuation pressure is adjusted. The gas in the cavity is extracted through the upper mold evacuation hole and the upper mold vacuum groove. At the same time, a negative pressure environment is formed inside the upper mold vacuum groove to adsorb the sample. Finally, the vulcanizing machine's pressing program is started to complete the pressing. Throughout the sample pressing process, the upper mold evacuation hole and the upper mold vacuum groove effectively vent the cavity, preventing pits in the sample and effectively improving the testing results.

[0008] Furthermore, the lower mold is internally provided with a lower mold vacuum groove, a lower mold evacuation hole, and a lower mold connection hole. The lower mold connection hole is located on the side of the lower mold, and the lower mold evacuation hole is located on the surface that is in contact with the upper mold. The vacuum groove is connected to the lower mold evacuation hole, and the lower mold connection hole is connected to the lower mold vacuum groove. After the pressing process is completed, the vacuum pump connection pipe on the upper mold connection hole needs to be removed and installed on the lower mold connection hole. Then, the vacuum pump is started to extract the gas in the lower mold vacuum groove, so that a negative pressure is formed in the lower mold vacuum groove to adsorb the pressed sample before demolding, effectively solving the problem of difficult sample demolding.

[0009] Furthermore, the diameter of the upper mold evacuation hole is set between 1 mm and 0.5 mm, and the diameter of the lower mold evacuation hole is set between 4 mm and 5 mm. The diameter of the upper mold evacuation hole needs to be set appropriately to avoid the sample mixture being sucked into the evacuation hole or vacuum tank during the vacuum pump evacuation process, which would cause blockage. The lower mold evacuation hole does not need to work when the mixture is being evacuated, so it can be set to be larger than the upper mold evacuation hole, but it cannot be too large, otherwise the amount of cutting required for processing will increase and the processing time will be increased.

[0010] Furthermore, both the upper mold vacuum groove and the lower mold vacuum groove are closed annular grooves surrounding the protrusion; the design of the upper mold vacuum groove and the lower mold vacuum groove can effectively increase the arrangement area of ​​the evacuation holes and increase the number of evacuation holes, thereby improving the evacuation efficiency.

[0011] Furthermore, both the upper mold evacuation hole and the lower mold evacuation hole are provided with a plurality of holes. The upper mold evacuation holes are evenly arranged along the contour of the upper mold vacuum groove, and the lower mold evacuation holes are evenly arranged along the contour of the lower mold vacuum groove. The even arrangement of the lower mold evacuation holes along the contour of the lower mold vacuum groove and the even arrangement of the upper mold evacuation holes along the contour of the upper mold vacuum groove can evenly extract air from the cavity or the sample, avoiding the presence of unextracted gas in the cavity.

[0012] Furthermore, it also includes a base plate, which is installed on the side of the lower mold away from the upper mold and in contact with the lower mold. The base plate is provided with several base plate protrusions, and the lower mold evacuation hole is a through hole. When the base plate is installed on the lower mold, the base plate protrusions are inserted into the lower mold evacuation hole, and the top surface of the base plate protrusions is flush with the top surface of the lower mold. The lower mold evacuation hole is a through hole. When the mold is closed and pressed, the lower mold evacuation hole is in a non-working state. The base plate protrusions are inserted into the lower mold evacuation hole to seal the entire lower mold evacuation hole. The top surface of the base plate protrusions is flush with the top surface of the lower mold, making the surface of the sample after pressing smoother and preventing the appearance of tiny protrusions formed by the evacuation hole.

[0013] Furthermore, it also includes a column member. The base plate is provided with a column hole, and the column member can be inserted into the column hole. After the column member is inserted into the column hole, the column member lifts the lower mold, so that the bottom surface of the lower mold is separated from the surface of the base plate, and the lower mold evacuation hole is in communication with the lower mold vacuum groove. After pressing is completed, the lower mold evacuation hole needs to enter the working state. The lower mold evacuation hole needs to be opened to communicate with the lower mold vacuum groove. The column member is placed into the column hole of the base plate. The column hole is a through hole. The column member penetrates the base plate and lifts the lower mold, so that the base plate protrusion descends in the lower mold evacuation hole, so that the lower mold evacuation hole is in communication with the lower mold vacuum groove.

[0014] Furthermore, the lower mold vacuum groove divides the lower mold evacuation hole into an upper hole on one side near the upper mold and a lower hole on the other side. After the column member lifts the lower mold, the top surface of the bottom plate protrusion is located in the lower hole. After the bottom surface of the lower mold separates from the bottom plate surface, a part of the bottom plate protrusion still needs to remain in the through-hole type lower mold evacuation hole to seal the opening at the bottom of the through hole, which facilitates the subsequent evacuation and demolding process of the lower mold vacuum groove, and also facilitates the bottom plate protrusion to extend back into the upper hole.

[0015] Furthermore, the edge of the protrusion is set as an inclined surface around the protrusion, and the angle between the inclined surface and the bottom surface of the cavity is greater than 0 degrees and does not exceed 10 degrees. The upper mold evacuation hole is located on the inclined surface. By setting the upper mold evacuation hole on the inclined surface, the sample in the molten state can achieve full flow through the inclined surface and the external force of vacuuming and discharge the bubbles generated by the vaporization of low boiling point substances. After the color masterbatch in the melt has flowed fully, it will not slowly sink in the cavity, which can avoid obvious upper and lower delamination of the material after compression molding. The inclination angle of the inclined surface should not be too large, otherwise the product will stick to the inclined surface after cooling, which will increase the difficulty of subsequent demolding.

[0016] Furthermore, the surface of the upper mold is provided with an upper mold sealing groove around the edge of the upper mold, and the surface of the lower mold is provided with a lower mold sealing groove around the edge of the lower mold. When the upper mold and the lower mold are closed, the upper mold sealing groove and the lower mold sealing groove are joined to form a sealing cavity. When the molds are closed, a sealing ring is placed in the upper mold sealing groove. When the upper and lower molds are closed, the thickness of the sealing ring is equal to the groove depth of the upper mold sealing groove plus the groove depth of the lower mold sealing groove, so as to prevent gas from entering the cavity from the parting surface during the vacuum pump extraction process.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] 1. The upper mold has a cavity on one side, and a protrusion is provided inside the cavity. When the upper and lower molds are closed, the side of the upper mold with the cavity fits against the lower mold. It also includes an upper mold vacuum groove, an upper mold evacuation hole, and an upper mold connection hole. The upper mold evacuation hole is located on the surface of the protrusion, the upper mold vacuum groove is located inside the upper mold and communicates with the cavity through the upper mold evacuation hole, and the upper mold connection hole is located on the side of the upper mold and communicates with the upper mold vacuum groove. During the entire pressing process, the upper mold evacuation hole and the upper mold vacuum groove can effectively vent the cavity, avoid pits in the sample, and effectively improve the test results.

[0019] 2. The lower mold is equipped with a lower mold vacuum groove, a lower mold air extraction hole, and a lower mold connection hole. During demolding, the vacuum pump connection pipe on the upper mold connection hole is removed and installed on the lower mold connection hole. The gas in the lower mold vacuum groove is extracted to create a negative pressure in the lower mold vacuum groove, which adsorbs the pressed sample before demolding, effectively solving the problem of difficult sample demolding. Attached Figure Description

[0020] Figure 1 A three-dimensional view of the upper mold of a laboratory flat vulcanizing machine pressing mold;

[0021] Figure 2 A cross-sectional view of the upper mold of a laboratory flat vulcanizing machine pressing mold;

[0022] Figure 3 for Figure 2 A magnified view of a section at point A in the middle;

[0023] Figure 4 A three-dimensional view of the lower mold of a laboratory flat vulcanizing machine pressing mold;

[0024] Figure 5 A sectional view of the lower die of a laboratory flat vulcanizing press mold;

[0025] Figure 6 for Figure 5 A magnified view of a section at point B in the middle;

[0026] Figure 7 This is a three-dimensional view of the base plate of a pressing mold for a laboratory flat vulcanizing machine.

[0027] In the attached diagram: 100, upper mold; 110, cavity; 120, protrusion; 121, inclined surface; 130, upper mold vacuum groove; 140, upper mold air extraction hole; 150, upper mold connecting hole; 160, upper mold sealing groove; 200, lower mold; 210, lower mold vacuum groove; 220, lower mold air extraction hole; 221, upper hole; 222, lower hole; 230, lower mold connecting hole; 240, lower mold sealing groove; 300, base plate; 310, base plate protrusion; 320, column hole; 400, column component. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0029] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0030] Example 1

[0031] This embodiment is a first embodiment of a pressing mold for a laboratory flat vulcanizing machine, such as... Figures 1 to 7 As shown, the mold includes an upper mold 100 and a lower mold 200. A cavity 110 is provided in one side of the upper mold 100, and a protrusion 120 is provided in the cavity 110. When the upper mold 100 and the lower mold 200 are closed, the side of the upper mold 100 with the cavity 110 fits against the lower mold 200. The mold also includes an upper mold vacuum groove 130, an upper mold air extraction hole 140, and an upper mold connecting hole 150. The upper mold air extraction hole 140 is located on the surface of the protrusion 120. The upper mold vacuum groove 130 is located inside the upper mold 100 and communicates with the cavity 110 through the upper mold air extraction hole 140. The upper mold connecting hole 150 is located on the side of the upper mold 100 and communicates with the upper mold vacuum groove 130.

[0032] Specifically, the lower mold 200 is internally equipped with a lower mold vacuum groove 210, a lower mold evacuation hole 220, and a lower mold connection hole 230. The lower mold connection hole 230 is located on the side of the lower mold 200, and the lower mold evacuation hole 220 is located on the surface that is in contact with the upper mold 100. The vacuum groove is connected to the lower mold evacuation hole 220, and the lower mold connection hole 230 is connected to the lower mold vacuum groove 210. After the pressing process is completed, the vacuum pump connection pipe on the upper mold connection hole 150 needs to be removed and installed on the lower mold connection hole 230. Then, the vacuum pump is started to extract the gas in the lower mold vacuum groove 210, so that a negative pressure is formed in the lower mold vacuum groove 210 to adsorb the pressed sample before demolding, which effectively solves the problem of difficult sample demolding.

[0033] Specifically, the diameter of the upper mold evacuation hole 140 is set between 1mm and 0.5mm; the diameter of the lower mold evacuation hole 220 is set between 4mm and 5mm. The diameter of the upper mold evacuation hole 140 needs to be set appropriately to avoid the sample mixture being sucked into the evacuation hole or vacuum chamber during the vacuum pump evacuation process, causing blockage. The lower mold evacuation hole 220 does not need to work when the mixture is being evacuated, so it can be set to be larger than the upper mold evacuation hole 140. However, it cannot be too large, otherwise the amount of cutting required for processing will increase and the processing time will be increased.

[0034] Specifically, both the upper mold vacuum groove 130 and the lower mold vacuum groove 210 are closed annular grooves surrounding the protrusion 120. The design of the upper mold vacuum groove 130 and the lower mold vacuum groove 210 can effectively increase the arrangement area of ​​the evacuation holes and increase the number of evacuation holes, thereby improving the evacuation efficiency. The closed annular groove can be circular or polygonal.

[0035] Specifically, there are several upper mold evacuation holes 140 and lower mold evacuation holes 220. The upper mold evacuation holes 140 are evenly arranged along the contour of the upper mold vacuum groove 130, and the lower mold evacuation holes 220 are evenly arranged along the contour of the lower mold vacuum groove 210. The even arrangement of the lower mold evacuation holes 220 along the contour of the lower mold vacuum groove 210 and the upper mold evacuation holes 140 along the contour of the upper mold vacuum groove 130 can evenly extract air from the cavity 110 or the sample, avoiding the presence of unextracted gas in the cavity 110.

[0036] Specifically, it also includes a base plate 300, which is installed on the side of the lower mold 200 away from the upper mold 100 and is in contact with the lower mold 200. The base plate 300 is provided with several base plate protrusions 310, and the lower mold evacuation hole 220 is a through hole. When the base plate 300 is installed on the lower mold 200, the base plate protrusions 310 are inserted into the lower mold evacuation hole 220, and the top surface of the base plate protrusions 310 is flush with the top surface of the lower mold 200. The lower mold evacuation hole 220 is a through hole. When the mold is closed and pressed, the lower mold evacuation hole 220 is in a non-working state. The base plate protrusions 310 are inserted into the lower mold evacuation hole 220 to close the entire lower mold evacuation hole 220. The top surface of the base plate protrusions 310 is flush with the top surface of the lower mold 200, so that the surface of the sample after pressing is smoother and there will be no small protrusions formed by the evacuation hole.

[0037] The working principle of a laboratory flat vulcanizing machine pressing mold in this embodiment is as follows:

[0038] During the pressing process, a base plate 300 is installed below the lower mold 200, with the base plate protrusion 310 inserted into the lower mold evacuation hole 220. The upper mold connection hole 150 is connected to a vacuum pump, which extracts the gas from the cavity 110 and the sample through the upper mold evacuation hole 140. At the same time, a negative pressure is formed in the upper mold vacuum groove 130 to maintain the adsorption of the sample until the pressing is completed. After pressing is completed, the vacuum pump is switched to the lower mold connection hole 230, and the base plate 300 is separated so that the lower mold evacuation hole 220 is connected to the lower mold vacuum groove 210. A pressurizing or inflation device is connected to the upper mold connection hole 150. During demolding, the pressurizing device blows air onto the product through the upper mold evacuation hole 140, and the vacuum pump adsorbs the product through the lower mold evacuation hole 220. After the upper mold 100 and the lower mold 200 are separated, the pressed sample can be adsorbed on the surface of the lower mold 200 and will not be embedded in the cavity 110 of the upper mold 100 and difficult to remove.

[0039] The beneficial effects of this embodiment are as follows: During the sample pressing process, the upper mold venting hole 140 and the upper mold vacuum groove 130 can effectively vent the cavity 110, avoid pitting in the sample, and effectively improve the test results. When the sample is demolded, the pressurizing device blows air into the product through the upper mold venting hole 140, and the vacuum pump adsorbs through the lower mold venting hole 220. After the upper mold 100 and the lower mold 200 are separated, the pressed sample can be adsorbed on the surface of the lower mold 200, effectively preventing the sample from being embedded in the cavity 110 of the upper mold 100 and difficult to remove.

[0040] Example 2

[0041] This embodiment is a second embodiment of a pressing mold for a laboratory flat vulcanizing machine, such as... Figure 6 and 7 As shown, the difference from Embodiment 1 is as follows:

[0042] Specifically, it also includes a column member 400. The base plate 300 is provided with a column hole 320. The column member 400 can be inserted into the column hole 320. After the column member 400 is inserted into the column hole 320, the column member 400 lifts the lower mold 200, so that the bottom surface of the lower mold 200 is separated from the surface of the base plate 300, and the lower mold evacuation hole 220 is in a connected state with the lower mold vacuum groove 210. After pressing is completed, the lower mold evacuation hole 220 needs to enter the working state. The lower mold evacuation hole 220 needs to be opened to connect with the lower mold vacuum groove 210. The column member 400 is placed into the column hole 320 of the base plate 300. The column hole 320 is a through hole. The column member 400 penetrates the base plate 300 and lifts the lower mold 200, so that the base plate protrusion 310 can descend in the lower mold evacuation hole 220, so that the lower mold evacuation hole 220 is connected with the lower mold vacuum groove 210.

[0043] Specifically, the lower mold vacuum groove 210 divides the lower mold evacuation hole 220 into an upper hole 221 on one side near the upper mold 100 and a lower hole 222 on the other side. After the column member 400 lifts the lower mold 200, the top surface of the bottom plate protrusion 310 is located in the lower hole 222. After the bottom surface of the lower mold 200 separates from the surface of the bottom plate 300, a part of the bottom plate protrusion 310 still needs to remain in the through hole type lower mold evacuation hole 220 to seal the opening at the bottom of the through hole, so as to facilitate the subsequent work of the lower mold vacuum groove 210 of the lower mold 200 for evacuation and demolding, and also to facilitate the bottom plate protrusion 310 to extend into the upper hole 221 again.

[0044] The working principle of a laboratory flat vulcanizing machine pressing mold in this embodiment is as follows:

[0045] When demolding the sample, the entire mold is lifted manually. After inserting the column 400 into the column hole 320 of the base plate 300, the entire mold is laid flat. The base plate 300 is then manually pressed down to detach it from the lower mold 200. The base plate protrusion 310 slides in the lower mold evacuation hole 220 as the base plate 300 moves. The top surface of the base plate protrusion 310 slides into the lower hole 222, and the upper hole 221 can then connect with the lower mold vacuum groove 210.

[0046] The beneficial effects of this embodiment are: by setting the column member 400 and inserting the column member 400 into the column hole 320, the base plate 300 and the lower mold 200 can be effectively separated, while the lower mold air extraction hole 220 and the lower mold vacuum groove 210 can be kept connected.

[0047] Example 3

[0048] This embodiment is a third embodiment of a pressing mold for a laboratory flat vulcanizing machine, such as... Figure 3 and 6 As shown, the difference from Embodiment 1 is as follows:

[0049] Specifically, the edge of the protrusion 120 is set as an inclined surface 121 around the protrusion 120. The angle between the inclined surface 121 and the bottom surface of the cavity 110 is greater than 0 degrees and does not exceed 10 degrees. The upper mold evacuation hole 140 is located on the inclined surface 121. By setting the upper mold evacuation hole 140 on the inclined surface 121, the sample in the molten state can achieve full flow through the inclined surface 121 and the external force of vacuuming and discharge the bubbles generated by the vaporization of low boiling point substances. After the color masterbatch in the melt has flowed fully, it will not slowly sink in the cavity 110, which can avoid obvious upper and lower delamination of the material after compression molding. The inclination angle of the inclined surface 121 should not be too large, otherwise the product will stick to the inclined surface 121 after cooling, which will increase the difficulty of subsequent demolding.

[0050] Specifically, the surface of the upper mold 100 is provided with an upper mold sealing groove 160 around the edge of the upper mold 100, and the surface of the lower mold 200 is provided with a lower mold sealing groove 240 around the edge of the lower mold 200. When the upper mold 100 and the lower mold 200 are closed, the upper mold sealing groove 160 and the lower mold sealing groove 240 are joined to form a sealing cavity. When the molds are closed, a sealing ring is placed in the upper mold sealing groove 160. When the lower mold 200 is closed, the thickness of the sealing ring is equal to the groove depth of the upper mold sealing groove 160 plus the groove depth of the lower mold sealing groove 240, so as to prevent gas from entering the cavity 110 from the parting surface during the vacuum pump extraction process.

[0051] The working principle of a laboratory flat vulcanizing machine pressing mold in this embodiment is as follows:

[0052] When closing the mold, first place the sealing ring in the upper mold sealing groove 160, then close the upper and lower molds 200. After completing the mold closing steps, the vacuum pump can be started to perform the air extraction operation.

[0053] The beneficial effects of this embodiment are: by setting the upper mold sealing groove 160 and the lower mold sealing groove 240 and installing the sealing ring, the gas is effectively prevented from entering the cavity 110 from the parting surface during the vacuum pumping process, thus improving the exhaust effect.

[0054] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0055] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A press molding die for a laboratory press vulcanizer, comprising an upper die (100) and a lower die (200), a cavity (110) is provided in one side of the upper die (100), a protrusion (120) is provided in the cavity (110), when the upper die (100) and the lower die (200) are closed, the side of the upper die (100) provided with the cavity (110) is attached to the lower die (200), characterized in that, The upper die (100) is provided with an upper die vacuum groove (130), an upper die air extraction hole (140) and an upper die connecting hole (150). The upper die air extraction hole (140) is located on the surface of the convex part (120), the upper die vacuum groove (130) is located in the interior of the upper die (100) and communicates with the cavity (110) through the upper die air extraction hole (140), and the upper die connecting hole (150) is located on the side of the upper die (100) and communicates with the upper die vacuum groove (130).

2. A press mold for a laboratory press according to claim 1, characterized in that The lower die (200) is provided with a lower die vacuum groove (210), a lower die air extraction hole (220) and a lower die connecting hole (230). The lower die connecting hole (230) is located on the side of the lower die (200), the lower die air extraction hole (220) is located on the surface in contact with the upper die (100), the lower die vacuum groove (210) communicates with the lower die air extraction hole (220), and the lower die connecting hole (230) communicates with the lower die vacuum groove (210).

3. A press mold for a laboratory press according to claim 2, characterized in that The diameter of the upper die air extraction hole (140) is set to be between 1 mm and 0.5 mm, and the diameter of the lower die air extraction hole (220) is set to be between 4 mm and 5 mm.

4. A press mold for a laboratory press according to claim 2, wherein The upper die vacuum groove (130) and the lower die vacuum groove (210) are both closed ring type grooves surrounding the convex part (120).

5. A press mold for a laboratory press according to claim 4, characterized in that The upper die air extraction hole (140) and the lower die air extraction hole (220) are both provided with a plurality of holes. The upper die air extraction holes (140) are uniformly arranged along the contour of the upper die vacuum groove (130), and the lower die air extraction holes (220) are uniformly arranged along the contour of the lower die vacuum groove (210).

6. A press mold for a laboratory press according to claim 2, wherein The bottom plate (300) is installed on the side of the lower die (200) away from the upper die (100) and is in contact with the lower die (200). The bottom plate (300) is provided with a plurality of bottom plate convex parts (310), and the lower die air extraction hole (220) is a through hole. When the bottom plate (300) is installed on the lower die (200), the bottom plate convex parts (310) are inserted into the lower die air extraction holes (220), and the top surface of the bottom plate convex parts (310) is flush with the top surface of the lower die (200).

7. A press mold for a laboratory press according to claim 6, characterized in that The bottom plate (300) is provided with a column hole (320), and the column part (400) can be inserted into the column hole (320). After the column part (400) is inserted into the column hole (320), the column part (400) lifts the lower die (200) to separate the bottom surface of the lower die (200) from the surface of the bottom plate (300) and to put the lower die air extraction hole (220) in communication with the lower die vacuum groove (210).

8. A press mold for a laboratory press according to claim 7, characterized in that The lower die vacuum groove (210) divides the lower die air extraction hole (220) into an upper hole (221) close to the upper die (100) and a lower hole (222) on the other side. After the column part (400) lifts the lower die (200), the top surface of the bottom plate convex part (310) is located in the lower hole (222).

9. A press mold for a laboratory press according to claim 1, wherein The edge of the protruding part (120) is provided with an inclined surface (121) around the protruding part (120), the included angle of the inclined surface (121) with the bottom surface of the cavity (110) ranges from more than 0 degree to not more than 10 degrees, and the upper die air extraction hole (140) is located on the inclined surface (121).

10. A press mold for a laboratory press according to any one of claims 1-9, characterized in that The surface of the upper die (100) is provided with an upper die sealing groove (160) around the edge of the upper die (100), the surface of the lower die (200) is provided with a lower die sealing groove (240) around the edge of the lower die (200), and when the upper die (100) and the lower die (200) are closed, the upper die sealing groove (160) and the lower die sealing groove (240) are spliced to form a sealing cavity.

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