Balancing device, clamp and method for high-temperature and high-pressure true triaxial large-displacement shear experiment

Abstract

The invention provides a balancing device, a clamp and a method for a high-temperature and high-pressure true triaxial large-displacement shear experiment, and belongs to the technical field of high-temperature and high-pressure rock mechanics experiments. The balancing device comprises a connector and a flexible shell. And a liquid channel is arranged in the joint. And a cavity is formed in the flexible shell. And the flexible shell is hermetically connected with the joint. The liquid channel is communicated with the cavity. And the confining pressure medium can enter the cavity through the liquid channel. The side, away from the connector, of the flexible shell is used for abutting against the rock sample so as to balance bending moment generated by normal stress in the shearing process. The balancing device for the high-temperature and high-pressure true triaxial large-displacement shear experiment can balance the moment of force generated by normal stress along with shear displacement in the shear experiment process, and the large-displacement shear experiment is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature and high-pressure rock mechanics experiments, and specifically relates to a balancing device, a fixture and a method for a high-temperature and high-pressure true triaxial large-displacement shear experiment. Background Art

[0002] Geotechnical engineering and deep energy development include mining engineering, tunnel excavation, nuclear waste treatment, carbon dioxide storage, wastewater treatment, geothermal energy production and oil and gas production. With the continuous utilization of shallow geotechnical engineering resources, the depth of geotechnical engineering application scenarios continues to increase, from hundreds of meters to thousands of meters. The basic occurrence environment of deep geotechnical engineering is a high-temperature, three-dimensional, high-stress, and high-fluid pressure environment. In order to better improve the safety of deep geotechnical engineering mining and development, it is necessary to explore the shear properties of rock masses and rocks related to the engineering, especially the increase in depth and the impact of high temperature and high pressure on the shear properties of rocks.

[0003] Traditional direct shear equipment and double shear equipment are easy and fast to operate, and extremely convenient, but they also have obvious disadvantages. That is, as the shear displacement continues to increase, the applied normal stress will produce an obvious bending moment, which will have an uncorrectable effect on the shear displacement curve, resulting in the inability to accurately obtain the mechanical properties of rocks under large displacement shear. Therefore, such equipment cannot carry out large displacement shear experiments on rocks. At the same time, due to the limitations of such equipment itself, the expansion of temperature modules and high-pressure seepage modules is very difficult, so most direct shear equipment and double shear equipment can only carry out conventional shear experiments, which also leads to their stress state not being consistent with the actual occurrence environment.

[0004] Therefore, the triaxial shear test equipment was born, which can easily realize the expansion of temperature modules and high-pressure fluid modules, and the stress conditions are closer to the real environment. However, there are also obvious disadvantages. First, the triaxial shear test equipment realizes shearing through an oblique section. During the loading process, its normal stress is not constant, but changes with the change of shear stress, which leads to the inability to effectively control variables during the experiment; secondly, most triaxial shear test equipment uses heat shrink tubes for sealing. When the shear displacement is too large, the heat shrink tube will be punctured, causing the failure of the experiment, so it is impossible to realize large displacement shear experiments; the last point is that the heat shrink tube has limited temperature resistance, and the temperature will cause the heat shrink tube to shrink and deform, which also affects the accurate measurement of rock deformation.

[0005] In addition, since the stress state of some shallow geotechnical engineering projects is actually true triaxial, and the deep energy engineering projects are even more complex true triaxial stress states, and are accompanied by high temperatures and high flow pressures, when conducting large displacement shear experiments under high temperature and high pressure, traditional direct shear equipment, double shear equipment and triaxial shear test equipment cannot meet the experimental requirements. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to provide a balancing device, a fixture and a method for high-temperature and high-pressure true triaxial large-displacement shear experiments, which can balance the bending moment generated by the normal stress during the shear process and realize high-temperature and high-pressure true triaxial large-displacement shear tests.

[0007] In a first aspect, the present invention provides a balancing device for high-temperature and high-pressure true triaxial large-displacement shear experiments, comprising: a joint and a flexible outer shell. A liquid channel is provided in the joint. A cavity is provided in the flexible outer shell. The flexible outer shell is sealingly connected to the joint. The liquid channel communicates with the cavity. The confining pressure medium can enter the cavity through the liquid channel. The side of the flexible outer shell away from the joint is used to abut against the rock sample to balance the bending moment generated by the normal stress during the shear process.

[0008] Wherein, a protective layer is provided on the flexible outer shell. The protective layer is located on the side of the flexible outer shell away from the joint.

[0009] Wherein, on the outer wall of the joint, a groove is provided along the circumferential direction of the joint. The groove is used to place a sealing ring. The sealing ring is used to be tightly connected to the maximum principal stress direction press head.

[0010] Wherein, the joint is made of metal. The flexible outer shell is made of silicone.

[0011] In a second aspect, the present invention provides a true triaxial fixture, comprising: a pair of maximum principal stress direction press heads and a pair of intermediate principal stress direction press heads. A pair of maximum principal stress direction press heads and a pair of intermediate principal stress direction press heads are closely abutted around the rock sample and are sequentially interlocked. An installation groove is provided on each maximum principal stress direction press head. The opening of the installation groove faces the rock sample. The balancing device as described above is provided in the installation groove. The flexible outer shell of the balancing device is attached to the surface of the rock sample. The minimum principal stress of the rock sample is the hydrostatic pressure, which is applied by a hydraulic system.

[0012] In a third aspect, the present invention provides a manufacturing method for manufacturing the balancing device for high-temperature and high-pressure true triaxial large-displacement shear experiments as described above. The method comprises the following steps: S1. Obtain a wax casting mold and a shell casting mold; S2. Install the joint on the wax casting mold, and use a metal rod to pass through the liquid channel and extend into the wax casting mold; S3. Pour paraffin into the wax casting mold; S4. After the paraffin cools, remove the wax casting mold to obtain a wax block; the wax block is connected to the joint through the metal rod to form a lost-wax model; S5. Place the lost-wax model in the shell casting mold; S6. Pour liquid silicone into the outer shell casting mold until the bottom of the wax block and the joint are submerged in the liquid silicone; S7. After the liquid silicone cures, remove the outer shell casting mold to form a flexible outer shell; the flexible outer shell is hermetically connected to the bottom of the joint, and the wax block is wrapped inside the flexible outer shell; S8. Take out the metal rod, melt and drain the wax block to obtain the balancing device.

[0013] Among them, the wax block casting mold includes: an annular fixing beam and four cavity shells. The four cavity shells are buckled with each other, and the four cavity shells are fastened together by the annular fixing beam to enclose a paraffin casting cavity. A wax injection hole is provided at the top of the paraffin casting cavity. An observation hole is provided on the side of the paraffin casting cavity. A positioning groove is provided on the outer side of the bottom of the paraffin casting cavity. A through hole is provided in the positioning groove. The through hole is communicated with the inside of the paraffin casting cavity.

[0014] Among them, step S2 includes: S21. Install the joint in the positioning groove; S22. Make the metal rod extend into the paraffin casting cavity through the liquid channel and the through hole in sequence.

[0015] Among them, step S3 includes: S31. Coat the inner wall of the paraffin casting cavity with a release agent; S32. Pour paraffin into the paraffin casting cavity through the wax injection hole, and observe the paraffin liquid level in the paraffin casting cavity through the observation hole; S33. Stop pouring paraffin when the paraffin is about to overflow from the observation hole.

[0016] Among them, the outer shell casting mold includes: a mold body, a baffle, a partition board, a cross beam and an overflow groove. The mold body is a bottomless structure and includes an annular side wall. The mold body includes a plurality of casting grooves. The baffle is arranged on the top of the mold body. An overflow hole is provided at the connection between the baffle and the mold body. The partition boards are arranged on the opposite sides of the casting grooves. And two adjacent casting grooves share a partition board. A clamping groove is provided at the top of each partition board. The cross beam is erected in the clamping groove at the top of the partition board. The cross beam includes a plurality of metal rod positioning holes. Each metal rod positioning hole corresponds to a casting groove. A joint positioning groove is provided at one end of the metal rod positioning hole facing the mold body. The overflow groove is arranged on the side of the mold body, and the overflow hole is connected to the overflow groove.

[0017] Among them, step S5 includes: S51. Install the lost wax model on the cross beam, insert the top of the metal rod into the metal rod positioning hole, and insert the top of the joint into the joint positioning groove; S52. Install the cross beam frame in the clamping groove at the top of the partition board; S53. Bond the bottom of the mold body to the bottom plate; S54. A fixing strip is arranged along the connection between the mold body and the bottom plate on the outer side of the mold body.

[0018] Among them, step S6 includes: S61. Coat a release agent on the inner wall of the pouring groove; S62. Pour liquid silicone into the pouring groove to a first liquid level height; S63. Place the outer shell casting mold into a vacuum autoclave, and evacuate the vacuum autoclave until no air bubbles are discharged from the liquid silicone in the pouring groove, then stop evacuating; S64. Open the vacuum autoclave, pour liquid silicone into the pouring groove until the liquid silicone flows into the overflow groove from the overflow hole, then stop; S65. Continue to evacuate the vacuum autoclave until no bubbles float out from the liquid silicone in the pouring groove, then stop; S66. Take out the outer shell casting mold in the vacuum autoclave and put it into an incubator for constant temperature cooling.

[0019] Beneficial effects: The balancing device for high-temperature and high-pressure true triaxial large-displacement shear experiments provided by the present invention can effectively balance the moment generated by the normal stress during the rock shear experiment using a confining pressure medium, effectively avoid the influence of bending moment on the experimental results, and make the results of the shear experiment more accurate; the balancing device for high-temperature and high-pressure true triaxial large-displacement shear experiments provided by the present invention can also balance the moment generated by the normal stress with the shear displacement during the shear experiment, realizing large-displacement shear experiments. Description of the drawings

[0020] Figure 1 It is a schematic structural diagram of a true triaxial fixture provided by an embodiment of the present invention; Figure 2 It is a sectional view of a true triaxial fixture provided by an embodiment of the present invention; Figure 3 It is a flowchart of a manufacturing method of the first embodiment provided by the present invention; Figure 4 It is a schematic structural diagram of a wax block casting mold provided by an embodiment of the present invention; Figure 5 It is a sectional view of a wax block casting mold provided by an embodiment of the present invention; Figure 6 It is a schematic structural diagram of a lost wax model provided by an embodiment of the present invention; Figure 7 It is a sectional view of a lost wax model provided by an embodiment of the present invention; Figure 8 It is a flowchart of a manufacturing method of the second embodiment provided by the present invention; Figure 9Flow chart of the manufacturing method of the third embodiment provided by the present invention; Figure 10 Structural schematic diagram of the shell casting mold of an embodiment provided by the present invention; Figure 11 Cross-sectional view of the shell casting mold of an embodiment provided by the present invention; Figure 12 Structural schematic diagram of a single shell casting mold of an embodiment provided by the present invention; Figure 13 Cross-sectional view of a single shell casting mold of an embodiment provided by the present invention; Figure 14 Flow chart of the manufacturing method of the fourth embodiment provided by the present invention; Figure 15 Flow chart of the manufacturing method of the fifth embodiment provided by the present invention.

[0021] The reference numerals are shown as: 1, balancing device; 2, true triaxial fixture; 3, wax block casting mold; 4, metal rod; 5, wax block; 6, shell casting mold; 7, single shell casting mold; 8, rock sample; 11, joint; 12, flexible shell; 13, liquid channel; 14, cavity; 15, protective layer; 16, first groove; 17, connecting part; 21, maximum principal stress direction indenter; 22, intermediate principal stress direction indenter; 23, mounting groove; 24, sealing ring; 31, annular fixing beam; 32, cavity shell; 33, paraffin casting cavity; 34, wax injection hole; 35, observation hole; 36, positioning groove; 37, through hole; 41, second groove; 61, mold body; 62, baffle; 63, partition; 64, cross beam; 65, overflow groove; 66, casting groove; 67, overflow hole; 68, clamping groove; 69, metal rod positioning hole; 610, joint positioning groove; 611, fixing strip; 71, single mold body; 72, cross beam support plate; 73, short cross beam; 74, positioning hole; 75, joint limiting groove; 76, cross beam clamping groove; 77, flexible shell casting groove. Detailed implementation manners

[0022] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0023] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0024] In the present invention, unless otherwise clearly specified and limited, the terms such as "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention and are not used to limit the present invention.

[0026] In a first aspect, this embodiment provides a true triaxial fixture 2. Figure 1 It is a schematic structural diagram of a true triaxial fixture 2 provided in this embodiment. Figure 2 It is a sectional view of the true triaxial fixture 2 provided in this embodiment.

[0027] As Figure 1 and Figure 2As shown in the figure, the true triaxial fixture 2 of this embodiment includes: a pair of major principal stress direction heads 21 and a pair of intermediate principal stress direction heads 22. The pair of major principal stress direction heads 21 and the pair of intermediate principal stress direction heads 22 are closely attached to the periphery of the rock sample 8 and are sequentially interlocked. Each major principal stress direction head 21 is provided with an installation groove 23. The opening of the installation groove 23 faces the rock sample 8. An equilibrium device 1 for high-temperature and high-pressure true triaxial large-displacement shear experiments is provided in the installation groove 23. The flexible outer shell 12 of the equilibrium device 1 is attached to the surface of the rock sample 8. The minor principal stress of the rock sample 8 is the hydrostatic pressure, which is applied through a hydraulic system.

[0028] In this embodiment, there are two intermediate principal stress direction heads 22 and two major principal stress direction heads 21, a total of four pieces, which are closely attached to the periphery of the rock sample 8 and are sequentially interlocked and connected together. The intermediate principal stress direction heads 22 and the major principal stress direction heads 21 are both made of high-strength steel materials and can be machined by CNC. The intermediate principal stress direction heads 22 transfer the intermediate principal stress, and the major principal stress direction heads 21 transfer the major principal stress, which is also the shear stress. Among them, the minor principal stress is the hydrostatic pressure, which is applied hydraulically and is also the normal stress.

[0029] The rock sample 8 of this embodiment is the experimental object of this embodiment and can be any type of rock. It is made into a square sample of the required size by wire cutting. The requirements for its size ratio and surface flatness need to meet the relevant specifications of rock mechanics experiments. In some examples, the true triaxial fixture 2 can realize the true triaxial large-displacement shear experiment of a 50mm×50mm×50mm rock sample 8.

[0030] The true triaxial fixture 2 of this embodiment mainly plays the role of transmitting force. The applied true triaxial stress acts on the true triaxial fixture 2 and then is transmitted to the rock sample 8 to realize the shear test.

[0031] Among them, as Figure 1 and Figure 2 shown, the equilibrium device 1 for high-temperature and high-pressure true triaxial large-displacement shear experiments of this embodiment includes: a joint 11 and a flexible outer shell 12. A liquid channel 13 is provided in the joint 11. A cavity 14 is provided in the flexible outer shell 12. The flexible outer shell 12 is hermetically connected to the joint 11. The liquid channel 13 communicates with the cavity 14. The confining pressure medium can enter the cavity 14 through the liquid channel 13. The side of the flexible outer shell 12 away from the joint 11 is used to abut against the rock sample 8 to balance the bending moment generated by the normal stress during the shear process.

[0032] In some examples, as Figure 2 shown, the liquid channel 13 is an opening with a diameter of 4mm to facilitate the inflow of pressurized liquid into the internal cavity 14 to generate a moment to balance the moment brought by the normal stress during the shear process.

[0033] The balancing device 1 of this embodiment has a moment balancing function, which can effectively reduce the moment generated by the normal stress during the shearing process. During use, the joint 11 is installed in the indenter of the true triaxial experimental equipment, and the side of the flexible outer shell 12 away from the joint 11 contacts the rock sample 8. When conducting a fracturing experiment, the confining pressure medium is introduced into the cavity 14 through the liquid channel 13; after the pressurized liquid enters the cavity 14, as the experiment progresses and along with the movement of the indenter, the flexible outer shell 12 can deform well, generating a moment to balance the moment brought by the normal stress during the shearing process, and it will not affect the moment balancing function. At the same time, no additional stress will be generated during the shearing process, ensuring the reliability of the experiment.

[0034] The balancing device 1 for the high-temperature and high-pressure true triaxial large-displacement shearing experiment of this embodiment has a self-balancing feature, which can effectively balance the bending moment generated during the shearing process and achieve large-displacement shearing under true triaxial stress conditions. The balancing device 1 for the high-temperature and high-pressure true triaxial large-displacement shearing experiment of this embodiment can effectively balance the moment generated by the normal stress during the rock shearing experiment using the confining pressure medium, effectively avoiding the influence of the bending moment on the experimental results and making the results of the shearing experiment more accurate; the balancing device 1 for the high-temperature and high-pressure true triaxial large-displacement shearing experiment provided by this embodiment can also balance the moment generated by the normal stress with the shearing displacement during the shearing experiment, realizing the large-displacement shearing experiment.

[0035] Among them, as Figure 1 and Figure 2 shown, a protective layer 15 is provided on the flexible outer shell 12. The protective layer 15 is located on the side of the flexible outer shell 12 away from the joint 11.

[0036] The protective layer 15 of this embodiment is made of a soft silicone material.

[0037] In this embodiment, the protective layer 15 is provided on the side of the flexible outer shell 12 away from the joint 11, which can play a protective role for the flexible outer shell 14 and block the sharp rock chips generated during the shear failure process of the rock sample 8. Setting the protective layer 15 can prevent these rock chips from invading the space where the flexible outer shell 12 is located as the shearing displacement increases, avoiding puncturing the flexible outer shell 12 and causing the leakage of the pressurized liquid, polluting the surface of the rock sample 8 and resulting in the failure of the experiment.

[0038] Among them, as Figure 1 and Figure 2 shown, on the outer wall of the joint 11, a first groove 16 is provided along the circumferential direction of the joint. The first groove 16 is used to place the sealing ring 24. The sealing ring 24 is used to tightly connect with the indenter 21 in the direction of the maximum principal stress.

[0039] The joint 11 of this embodiment includes a main body portion and a connecting portion 17 that are connected to each other. The diameter of the connecting portion 17 is greater than the diameter of the main body portion. The liquid passage 13 penetrates through the main body portion and the connecting portion 17 axially. The first groove 16 is provided on the outer periphery of the main body portion. The flexible outer shell 12 wraps the connecting portion 17 therein, and there is a sealed connection between the flexible outer shell 12 and the connecting portion 17.

[0040] The surface of the joint 11 of this embodiment is subjected to a matte treatment to facilitate effective sealed bonding with the flexible outer shell 12.

[0041] In this embodiment, the first groove 16 is machined on the joint 11 for placing the sealing ring 24, which can enable the outer wall of the joint to be tightly connected to the inner wall of the pressure head to prevent the intrusion of liquid.

[0042] Among them, as Figure 1 and Figure 2 shown, the joint 11 is made of metal. The flexible outer shell 12 is made of silica gel.

[0043] The joint 11 of this embodiment is made of metal, such as high-strength steel, etc., has good strength and is corrosion-resistant. The flexible outer shell 12 is made of silica gel, such as industrial silica gel, etc., and has a soft texture and good elasticity.

[0044] In a second aspect, the present invention provides a manufacturing method for manufacturing the balance device 1 for the high-temperature and high-pressure true triaxial large-displacement shear experiment described above. Figure 3 It is a flowchart of the first manufacturing method provided for this embodiment.

[0045] As Figure 3 shown, the manufacturing method of this embodiment includes the following steps: S1. Obtain the wax block casting mold 3 and the outer shell casting mold 6.

[0046] Specifically, the wax block casting mold 3 and the outer shell casting mold 6 can be made by 3D printing. After using three-dimensional modeling software to draw the models of the wax block casting mold 3 and the outer shell casting mold 6, use an auxiliary tool, a 3D printer, to make them. The main material can be selected as PLA polylactic acid. After printing, a vernier caliper needs to be used to check the dimensions of relevant components. If the dimensions are unqualified, reprinting is required.

[0047] S2. Install the joint 11 on the wax block casting mold 3, and use the metal rod 4 to pass through the liquid passage and extend into the wax block casting mold 3; as Figure 4 and Figure 5 shown.

[0048] Specifically, the metal rod 4 is made of high-strength steel, and its main function is to connect the joint 11 and the wax block 5. For example, the metal rod 4 has a diameter of 3.9 mm and a length of 55 mm.

[0049] The metal rod 4 of this embodiment is provided with a second groove 41 to facilitate a more firm connection between the metal rod 4 and the wax block 5 and prevent deflection.

[0050] S3. Pour paraffin into the wax block casting mold 3.

[0051] Specifically, the paraffin used in this embodiment is liquid paraffin No. 58.

[0052] S4. After the paraffin cools, remove the wax block casting mold 3 to obtain the wax block 5; the wax block 5 is connected to the joint 11 through the metal rod 4 to form a lost-wax model. Figure 6 It is a schematic structural diagram of a lost-wax model provided by this embodiment. Figure 7 It is a cross-sectional view of the lost-wax model provided by this embodiment.

[0053] Specifically, after the lost-wax model is cooled and demolded, the surface of the wax block 5 needs to be trimmed to ensure that the surface of the wax block 5 is flat and meets the dimensional requirements.

[0054] S5. Place the lost-wax model in the outer shell casting mold 6; as Figure 10 and Figure 11 shown.

[0055] Specifically, the function of the outer shell casting mold 6 is to pour a flexible outer shell 12 at the bottom of the lost-wax model so that the flexible outer shell 12 and the joint 11 can be tightly and firmly bonded together.

[0056] S6. Pour liquid silicone into the outer shell casting mold 6 until the bottom of the wax block 5 and the joint 11 are immersed in the liquid silicone.

[0057] Specifically, when pouring the liquid silicone, the connection part of the wax block 5 and the joint 11 should be immersed in the liquid silicone to ensure a tight bond between the joint 11 and the flexible outer shell 12.

[0058] S7. After the liquid silicone solidifies, remove the outer shell casting mold 6 to form the flexible outer shell 12; the flexible outer shell 12 is hermetically connected to the bottom of the joint 11, and the wax block 5 is wrapped inside the flexible outer shell 12.

[0059] Specifically, after the flexible outer shell 12 is demolded, the flexible outer shell 12 needs to be trimmed to remove the excess silicone.

[0060] S8. Take out the metal rod 4, melt and drain the wax block 5 to obtain the balance device 1.

[0061] Specifically, tools such as pliers can be used to take out the metal rod 4, and then it is placed in an incubator. The temperature is set to the required temperature so that the wax block 5 inside the flexible outer shell 12 melts into liquid paraffin and flows out automatically. However, since some of the liquid paraffin cannot flow out completely, heat-resistant gloves need to be worn to manually extrude it.

[0062] The manufacturing method provided in this embodiment can realize the manufacturing of the above-mentioned balancing device 1 to assist in carrying out high-temperature and high-pressure true triaxial large-displacement experiments. Compared with the traditional shear test device, the balancing device 1 obtained by using the manufacturing method of this embodiment can effectively balance the torque generated by the normal stress during the rock shear test process by using the confining pressure medium, effectively avoiding the influence of bending moment on the test results and making the results of the shear test more accurate. Compared with the traditional shear test device, the balancing device 1 obtained by using the manufacturing method of this embodiment effectively balances the torque generated by the normal stress with the shear displacement during the shear test process, realizing a large-displacement shear test.

[0063] Figure 4 It is a schematic structural diagram of a wax block casting mold 3 provided in this embodiment. Figure 5 It is a cross-sectional view of the wax block casting mold 3 provided in this embodiment. Among them, as Figure 4 and Figure 5 shown, the wax block casting mold 3 includes: an annular fixed beam 31 and four cavity shells 32. The four cavity shells 32 are buckled together, and the four cavity shells 32 are fastened together by the annular fixed beam 31 to enclose a paraffin casting cavity 33. A wax injection hole 34 is provided at the top of the paraffin casting cavity 33. An observation hole 35 is provided on the side of the paraffin casting cavity 33. A positioning groove 36 is provided on the outer side of the bottom of the paraffin casting cavity 33. A through hole 37 is provided in the positioning groove 36. The through hole 37 communicates with the paraffin casting cavity 33.

[0064] The wax block casting mold 3 in this embodiment is made by 3D printing. The main material is PLA polylactic acid, which is used for casting the wax block 5 and connecting the wax block 5 and the metal rod 4 together.

[0065] The four cavity shells 32 are the main body for casting the wax block 5, and two adjacent cavity shells 32 are symmetric to each other. The cavity shell 32 is made by a 3D printer using PLA polylactic acid material and can be reused multiple times. Therefore, before each use, it is necessary to check the integrity of its size and structure. Only those with the size meeting the requirements and the structure being complete can be used continuously. For example, the wall thickness of the four cavity shells 32 is 3 mm. The external dimensions of the paraffin casting cavity 33 are: length 26 mm, width 14.5 mm, and height 42 mm.

[0066] The main function of the wax injection hole 34 is to facilitate the injection of liquid paraffin into the paraffin casting cavity 33 to form the wax block 5. For example, the diameter of the wax injection hole 34 is 10 mm.

[0067] The main function of the observation hole 35 is to facilitate observing whether the liquid paraffin fills the paraffin casting cavity 33. Meanwhile, the excess liquid paraffin can overflow from the observation hole 35 to prevent the cast wax block 5 from exceeding the specified size, which is inconvenient for subsequent use. For example, the length and width dimensions of the observation hole 35 are 22 mm × 10 mm.

[0068] The main function of the positioning groove 36 is to fix the joint 11 and prevent the joint 11 from deflecting during the casting process, which may lead to casting failure. The size of the positioning groove 36 is adapted to the connecting part of the joint. For example, the size of the positioning groove 36 is 21 mm × 14 mm.

[0069] The main function of the annular fixing beam 31 is to fix the paraffin casting cavity 33 assembled by four cavity shells 32, and at the same time, there is no gap between the four cavity shells 32 to prevent the liquid paraffin from flowing out. For example, the thickness of the annular fixing beam 31 is 3 mm, and the external dimensions of length, width, and height are 61 mm × 38 mm × 15 mm.

[0070] The paraffin casting cavity 33 is the space for forming the wax block 5. The liquid paraffin enters the paraffin casting cavity 33 through the wax injection hole 34 at the top and forms the wax block 5 after cooling and solidification. For example, the internal dimensions of the paraffin casting cavity 33 are 44 mm × 19 mm × 21 mm.

[0071] In this embodiment, the metal rod 4 passes through the through hole 37 into the paraffin casting cavity 33 and finally bonds with the solidified wax block 5. For example, the diameter of the through hole 37 is 4 mm.

[0072] In this embodiment, the thickness of the bottom partition of the paraffin casting cavity 33 is 1 mm. Its main function is to separate the joint 11 from the wax block 5 so that when casting the flexible outer shell 12, the connection between the flexible outer shell 12 and the joint 11 can be more firm and tight.

[0073] Figure 8 It is a flowchart of the second manufacturing method provided for this embodiment. Among them, as Figure 8 shown, step S2 includes: S21. Install the joint 11 in the positioning groove 36.

[0074] Specifically, install the connecting part 17 of the joint 11 in the positioning groove 36 to prevent the joint 11 from deflecting during the casting process, which may lead to casting failure.

[0075] S22. Make the metal rod 4 extend into the paraffin casting cavity 33 through the liquid channel 13 and the through hole 37 in sequence.

[0076] Specifically, make the end of the metal rod 4 with the second groove 41 extend into the paraffin casting cavity 33 through the liquid channel 13 and the through hole 37 in sequence.

[0077] In addition, before installing the joint 11 in this embodiment, the wax block casting mold 3 needs to be assembled: First, four cavity shells 32 are assembled together to form a paraffin casting cavity 33; then, the four cavity shells 32 are fastened together by an annular fixing beam 31; and carefully check whether there are any gaps in the assembly. If there are gaps, reassembly is required. It should be noted that these components can be reused, so before reuse, the dimensions of each component need to be rechecked using a vernier caliper to ensure that the dimensions meet the requirements.

[0078] Figure 9 It is a flowchart of the third manufacturing method provided for this embodiment. Among them, as Figure 9 shown, step S3 includes: S31. Coat a release agent on the inner wall of the paraffin casting cavity 33.

[0079] Specifically, place the assembled wax block casting mold 3 on the ground or workbench surface, and evenly spray the release agent on the inner wall surface of the paraffin casting cavity 33. Its main function is to facilitate demolding and prevent the paraffin and the wax block casting mold 3 from sticking together, resulting in inability to demold or damage to the wax block 5.

[0080] S32. Pour paraffin into the paraffin casting cavity 33 through the wax injection hole 34, and observe the paraffin liquid level in the paraffin casting cavity 33 through the observation hole 35.

[0081] Specifically, first, use an incubator to dissolve solid paraffin, including: put 58# paraffin into a container and place it in the incubator. The temperature of the incubator is set at 70°C. It should be noted that the temperature cannot be set too high because the wax block casting mold is made of PLA polylactic acid and has limited heat resistance. It will deform at high temperatures. The paraffin liquid above 70°C will cause it to deform during the process of pouring into the wax block casting mold, resulting in the obtained wax block not meeting the dimensional requirements. After all the 58# paraffin is dissolved, use crucible tongs to clamp out the container containing the liquid paraffin and slowly pour the liquid 58# paraffin into the paraffin casting cavity 33 of the wax block casting mold 3 from the wax injection hole 34.

[0082] S33. Stop pouring paraffin when the paraffin is about to overflow from the observation hole 35.

[0083] Specifically, the volume of the liquid 58# paraffin will shrink during the solidification process. Therefore, when it is found that the liquid level is lower than the specified liquid level, it is necessary to appropriately replenish the liquid level again from the wax injection hole to meet the requirements during the solidification process.

[0084] In addition, after pouring is completed, it is necessary to stand still for about four hours to ensure that the 58# paraffin has enough time to fully solidify. Then, the annular fixed beam 31, the four cavity shells 32, and the bottom partition are removed in sequence. However, at this time, the surface of the wax block 5 is not flat and the dimensions do not fully meet the requirements. Tools need to be used to trim the surface of the wax block 5, and a vernier caliper is used to check its dimensions in a timely manner until the requirements are met. Finally, a lost-wax model is obtained.

[0085] Figure 10 Schematic structural diagram of a housing pouring mold 6 provided in this embodiment. Figure 11 Cross-sectional view of the housing pouring mold 6 provided in this embodiment. Among them, as Figure 10 and Figure 11 shown, the housing pouring mold 6 includes: a mold body 61, a baffle 62, a partition 63, a cross beam 64, and an overflow groove 65. The mold body 61 has a bottomless structure and includes an annular side wall. The mold body 61 includes a plurality of pouring grooves 66. The baffle 62 is arranged at the top of the mold body 61. An overflow hole 67 is provided at the connection between the baffle 62 and the mold body 61. The partition 63 is arranged on opposite sides of the pouring groove 66. And two adjacent pouring grooves 66 share a partition 63. A clamping groove 68 is provided at the top of each partition 63. The cross beam 64 is erected in the clamping groove 68 at the top of the partition 63. The cross beam 64 includes a plurality of metal rod positioning holes 69. Each metal rod positioning hole 69 corresponds to a pouring groove 66. A joint positioning groove 610 is provided at one end of the metal rod positioning hole 69 facing the mold body 61. The overflow groove 65 is arranged on the side of the mold body 61, and the overflow hole 67 is connected to the overflow groove 65.

[0086] The housing pouring mold 6 of this embodiment is printed by a 3D printer using PLA polylactic acid material, and it can be reused multiple times. Its main function is to pour silicone to form a flexible housing 12 on the joint 11, and finally form the balancing device 1 in the above embodiment.

[0087] In this embodiment, the main function of the cross beam 64 is to fix the joint 11. For example, the cross beam 64 has a thickness of 3 mm, a length of 149 mm, a width of 25 mm, and is equally spaced in 6 numbers with a spacing of 29 mm. Five 4-mm metal rod positioning holes 69 are equally spaced and used to pass through the metal rod 4.

[0088] The joint positioning groove 610 of this embodiment is used to fix the joint 11 to prevent it from shifting during the process of pouring silicone. For example, the joint positioning groove 610 of this embodiment is designed as a circular groove with a diameter of 15 mm. The partition 63 of this embodiment is provided with a card slot 68 for embedding the cross beam 64 and tightly clamping the cross beam 64 to prevent affecting the positioning. For example, the thickness of the partition 63 is 3 mm, and there are a total of 6, evenly distributed, with dimensions of 35 mm × 25 mm × 3 mm. The size of the card slot is 25 mm × 4.5 mm × 3 mm.

[0089] The function of the baffle 62 in this embodiment is to increase the height of the mold body 61 and prevent the insufficient height of the cast flexible shell 12.

[0090] A large number of air bubbles will be mixed into the silicone during the pouring process, and silicone will overflow during the defoaming process. Therefore, an overflow hole 67 is designed at the upper part of the mold body 61 in this embodiment, which can effectively discharge the excess silicone during the pouring and defoaming processes.

[0091] The overflow groove 65 in this embodiment is used to collect the silicone flowing out from the overflow hole 67. For example, the specific size of the overflow groove 65 is 20 mm × 5 mm × 3 mm.

[0092] The mold body 61 of this embodiment is the main body for casting the flexible shell 12, which is made of PLA polylactic acid material, and the bottom surface adopts a bottomless design to facilitate the demolding of the silicone in the later stage. For example, the inner wall size of the mold body 61 is 149 mm × 58 mm × 21.5 mm.

[0093] Figure 14 It is a flowchart of the fourth manufacturing method provided for this embodiment. Among them, as Figure 14 shown, step S5 includes: S51. Install the lost-wax model on the cross beam 64, insert the top of the metal rod 4 into the metal rod positioning hole 69, and insert the top of the joint 11 into the joint positioning groove 610.

[0094] Specifically, pass the metal rod 4 on the lost-wax model through the metal rod positioning hole 69, and fix the joint 11 in the joint positioning groove 610. When fixing, ensure that the long side of the wax block 5 is perpendicular to the long side of the cross beam 64.

[0095] S52. Install the cross beam 64 in the card slot 68 at the top of the partition 63.

[0096] Specifically, fix the cross beam 64 on the card slot 68 and appropriately adjust the position to ensure that the wax block 5 is centered in the pouring groove 66, and the distance from the four sides of the pouring groove 66 is 3 mm, ensuring that the wall thickness of the cast flexible shell 12 is uniform.

[0097] S53. Bond the bottom of the mold body 61 to the bottom plate.

[0098] Specifically, the bottom plate can be made of transparent acrylic board. Place the mold body 61 of the outer shell casting mold 6 on the transparent acrylic board, fix it with hot melt adhesive while sealing the bottom gap to prevent the silicone from flowing out at the bottom.

[0099] S54. On the outside of the mold body 61, a fixing strip 611 is provided along the connection between the mold body 61 and the bottom plate.

[0100] Specifically, the function of the fixing strip 611 is bonding and fixing. Since the mold body 61 adopts a bottomless design, it is necessary to fix the mold body 61 to the acrylic board with glue. Therefore, the fixing strip 611 is needed for reinforcement to improve the sealing and firmness of the connection between the mold body 61 and the bottom plate.

[0101] In addition, before step S51, it also includes: assembling the outer shell casting mold 6. Specifically, the mold body 61, the overflow groove 65, the baffle 62, and the partition 63 are assembled in sequence.

[0102] It should be noted that in some other embodiments, if only one balance device 1 of the above embodiment needs to be manufactured, this embodiment also provides a single outer shell casting mold 7. Figure 12 The structural schematic diagram of a single outer shell casting mold 7 provided by this embodiment. Figure 13 The cross-sectional view of the single outer shell casting mold 7 provided by this embodiment.

[0103] As Figure 12 and Figure 13 shown, the single outer shell casting mold 7 includes a single mold body 71, a crossbeam support plate 72, and a short crossbeam 73. The structure of the single outer shell casting mold 7 is similar to that of the above-mentioned outer shell casting mold 6. The crossbeam support plate 72 is arranged on the opposite sides of the single mold body 71 for supporting the short crossbeam 73. For example, the thickness of the short crossbeam 73 is 3 mm, the length is 33 mm, and the width is 15 mm. A positioning hole 74 is designed at the center position of the short crossbeam 73 for fixing the metal rod 4. For example, the diameter of the positioning hole 74 is 4 mm. A circular groove is provided on the side of the positioning hole 74 facing the single mold body 71 as a joint limit groove 75 for fixing the joint 11 with the wax block 5 to prevent deviation during the silicone casting process. A crossbeam slot 76 is designed at the top of the crossbeam support plate 72 for clamping the short crossbeam 73. For example, the size of the crossbeam support plate 72 is 48 mm × 21 mm × 2 mm.

[0104] There is only one flexible outer shell casting groove 77 in the single mold body 71, which is made of PLA polylactic acid material, and the specific size is 54 mm × 29 mm × 21.5 mm.

[0105] Figure 15 The flowchart of the fifth manufacturing method provided by this embodiment. Among them, asFigure 15 As shown, step S6 includes: S61. Coat the inner wall of the pouring tank 66 with a release agent.

[0106] Specifically, before pouring the silicone rubber, evenly spray a silicone rubber release agent on the inner wall surface of the pouring tank 66 to facilitate the later release of the silicone rubber.

[0107] S62. Pour liquid silicone rubber into the pouring tank 66 to the first liquid level height.

[0108] Specifically, take the silicone rubber out of the bottle and place it in a beaker, stir it thoroughly to make it evenly mixed, and slowly pour it into the pouring tank 66. Among them, the first liquid level height can be half of the height of the pouring tank 66.

[0109] S63. Place the outer shell casting mold 6 into the vacuum autoclave, and evacuate the vacuum autoclave until no air bubbles are discharged from the liquid silicone rubber in the pouring tank 66, then stop evacuating the vacuum.

[0110] Specifically, place the outer shell casting mold 6 into the vacuum autoclave, connect and start the vacuum pump, evacuate the vacuum to make the bubbles in the silicone rubber float up and be discharged, and stop evacuating the vacuum after a few minutes when no large air bubbles are discharged.

[0111] S64. Open the vacuum autoclave, pour liquid silicone rubber into the pouring tank 66 until the liquid silicone rubber flows into the overflow tank 65 from the overflow hole 67 and then stop.

[0112] Specifically, open the vacuum autoclave and continue to pour the remaining silicone rubber into the pouring tank 66 until the silicone rubber flows out from the overflow hole 67 and enters the overflow tank 65, then stop pouring the silicone rubber.

[0113] S65. Continue to evacuate the vacuum autoclave until no bubbles float up from the liquid silicone rubber in the pouring tank 66, then stop.

[0114] Specifically, close the vacuum autoclave again and start the vacuum pump for secondary evacuation. At the same time, carefully observe the silicone rubber liquid level. When it is lower than the specified position, stop evacuating the vacuum, supplement the silicone rubber and then continue to evacuate the vacuum. Observe the silicone rubber until no bubbles float up, then stop evacuating the vacuum.

[0115] S66. Take out the outer shell casting mold 6 from the vacuum autoclave and place it in an incubator for constant temperature cooling.

[0116] Specifically, take out the outer shell casting mold 6 from the vacuum autoclave and place it in an incubator, set the temperature to a constant temperature of 40°C to accelerate the curing of the silicone rubber, observe the curing situation of the silicone rubber at irregular intervals, and take it out of the incubator after it is completely cured.

[0117] It is understandable that in addition to using the above-mentioned wax block casting mold 3 and outer shell casting mold 6 in the manufacturing method of this embodiment, other auxiliary equipment is also required, including a 3D printer, a vacuum autoclave, a vacuum pump, and an incubator.

[0118] The main function of the 3D printer is to print the required wax block casting mold 3 and outer shell casting mold 6 (and / or a single outer shell casting mold 7) using PLA polylactic acid material.

[0119] The main functions of the vacuum autoclave and the vacuum pump are to evacuate the air and remove the bubbles from the silicone. After the outer shell casting mold 6 or a single outer shell casting mold 7 is cast, a large amount of air bubbles are contained in the silicone. If these bubbles are not removed, it will affect the performance of the flexible outer shell 12. Therefore, after casting, the outer shell casting mold 6 or a single outer shell casting mold 7 needs to be placed in the vacuum autoclave, and the vacuum pump is used to evacuate the vacuum autoclave.

[0120] The main function of the incubator is to dissolve paraffin. For example, before the wax block 5 is cast, the incubator is needed to heat and dissolve the paraffin into a liquid state. When the wax block 5 inside the flexible outer shell 12 of the balancing device 1 is taken out, the incubator is also needed to heat and dissolve the paraffin into a liquid state. The incubator can achieve a constant temperature function of 100°C and can be used for heating and dissolving 58# paraffin.

[0121] In addition, after the outer shell casting mold 6 is taken out of the incubator, the demolding step is carried out. First, the outer shell casting mold 6 is removed from the bottom plate. Secondly, the cross beam 64 is removed. A blade is used to cut the silicone that is adhered together, and a thin iron sheet is inserted between the mold body 61 of the outer shell casting mold 6 and the silicone to separate them. Push the silicone forcefully to separate it from the outer shell casting mold 6.

[0122] After demolding, use scissors to trim it to remove the excess silicone. After the metal rod 4 is taken out using a tool, it is placed in the incubator, and the temperature is set to 70°C to melt the wax block 5 inside into liquid paraffin, allowing it to flow out automatically. However, part of the liquid paraffin cannot flow out completely, and it is necessary to wear high-temperature resistant gloves and manually squeeze it out.

[0123] However, there may still be some paraffin residues inside. Therefore, it is necessary to start the constant temperature water bath heating device, set the temperature to 65°C, and rinse repeatedly to fully wash out the paraffin residues inside the flexible outer shell 12.

[0124] After the rinsing is completed, dry the moisture, let it stand for a period of time to make the inside dry as well, and use scissors to trim again to make the surface flat and without excess silicone residues at the corners.

[0125] Finally, check whether the dimensions meet the requirements and whether the internal wall thickness is uniform, and reject the parts with non-compliant dimensions and uneven internal wall thickness.

[0126] Finally, a balancing device 1 that meets the requirements is obtained.

[0127] Those skilled in the art can easily understand that, on the premise of no conflict, the above advantageous ways can be freely combined and superimposed.

[0128] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and variations can still be made, and these improvements and variations should also be regarded as within the protection scope of the present invention.

Claims

1. An equilibrium device for high-temperature and high-pressure true triaxial large-displacement shear experiments, characterized in that, Comprising: A connector and a flexible outer shell; a liquid passage is provided in the connector; a cavity is provided in the flexible outer shell; The flexible outer shell is sealingly connected to the connector; the liquid passage communicates with the cavity; The confining pressure medium can enter the cavity through the liquid passage; One side of the flexible outer shell away from the connector is used to abut against the rock sample to balance the bending moment generated by the normal stress during the shearing process.

2. The equilibrium device for the high-temperature and high-pressure true triaxial large-displacement shear experiment according to claim 1, characterized in that, A protective layer is provided on the flexible outer shell; The protective layer is located on the side of the flexible outer shell away from the connector.

3. The balance device for the high-temperature and high-pressure true triaxial large-displacement shear experiment according to claim 1, characterized in that, On the outer wall of the connector, a groove is provided along the circumferential direction of the connector; the groove is used to place a sealing ring; the sealing ring is used to tightly connect with the maximum principal stress direction indenter.

4. The equilibrium device for high-temperature and high-pressure true triaxial large-displacement shear experiments according to claim 1, characterized in that, The connector is made of metal; the flexible outer shell is made of silica gel.

5. A true triaxial fixture, characterized in that, Comprising: A pair of maximum principal stress direction indenters and a pair of intermediate principal stress direction indenters; A pair of the maximum principal stress direction indenters and a pair of the intermediate principal stress direction indenters are closely attached to the periphery of the rock sample and are sequentially interlocked; Each of the maximum principal stress direction indenters is provided with an installation groove; the opening of the installation groove faces the rock sample; The balance device as described in any one of claims 1 to 4 is provided in the installation groove; the flexible outer shell of the balance device is attached to the surface of the rock sample; The minimum principal stress of the rock sample is hydrostatic pressure, which is applied by a hydraulic system.

6. A manufacturing method for manufacturing the equilibrium device for high-temperature and high-pressure true triaxial large-displacement shear experiments as described in any one of claims 1 to 4, characterized in that, The method comprises the following steps: S1. Obtain a wax casting mold and a shell casting mold; S2. Install the connector on the wax casting mold, and insert a metal rod through the liquid passage and into the wax casting mold; S3. Pour paraffin into the wax casting mold; S4. After the paraffin cools, remove the wax casting mold to obtain a wax block; the wax block is connected to the connector through the metal rod to form a lost-wax model; S5. Place the lost-wax model in the shell casting mold; S6. Pour liquid silica gel into the shell casting mold until the wax block and the bottom of the connector are immersed in the liquid silica gel; S7. After the liquid silica gel solidifies, remove the shell casting mold to form the flexible outer shell; the flexible outer shell is sealingly connected to the bottom of the connector, and the wax block is wrapped inside the flexible outer shell; S8. Take out the metal rod, melt and discharge the wax block to obtain the balance device.

7. The manufacturing method according to claim 6, characterized in that, The wax casting mold comprises: an annular fixed beam and four cavity shells; The four cavity shells are interlocked with each other, and the four cavity shells are fastened together by the annular fixed beam to enclose a paraffin casting cavity; A wax injection hole is provided at the top of the paraffin casting cavity; an observation hole is provided on the side of the paraffin casting cavity; a positioning groove is provided on the outer side of the bottom of the paraffin casting cavity; a through hole is provided in the positioning groove; the through hole communicates with the inside of the paraffin casting cavity; The step S2 comprises: S21. Install the connector in the positioning groove; S22. Insert the metal rod into the paraffin casting cavity through the liquid passage and the through hole in sequence.

8. The manufacturing method according to claim 7, characterized in that, The step S3 comprises: S31. Coat a release agent on the inner wall of the paraffin casting cavity; S32. Pour the paraffin into the paraffin casting cavity through the wax injection hole, and observe the paraffin liquid level in the paraffin casting cavity through the observation hole; S33. Stop pouring the paraffin when the paraffin is about to overflow from the observation hole.

9. The manufacturing method according to claim 6, characterized in that, The outer shell casting mold includes: a mold body, a baffle, a partition, a cross beam, and an overflow groove; The mold body has a bottomless structure and includes an annular side wall; the mold body includes a plurality of casting grooves; The baffle is arranged at the top of the mold body; an overflow hole is provided at the connection between the baffle and the mold body; The partition is arranged on opposite sides of the casting groove; and two adjacent casting grooves share one partition; a card slot is provided at the top of each partition; The cross beam is erected in the card slot at the top of the partition; the cross beam includes a plurality of metal rod positioning holes; each metal rod positioning hole corresponds to one casting groove; a joint positioning slot is provided at one end of the metal rod positioning hole facing the mold body; The overflow groove is arranged on the side of the mold body, and the overflow hole is connected to the overflow groove; The step S5 includes: S51. Install the lost wax model on the cross beam, insert the top of the metal rod into the metal rod positioning hole, and insert the top of the joint into the joint positioning slot; S52. Install the cross beam in the card slot at the top of the partition; S53. Bond the bottom of the mold body to the bottom plate; S54. On the outside of the mold body, arrange a fixing strip along the connection between the mold body and the bottom plate.

10. The manufacturing method according to claim 9, characterized in that, The step S6 includes: S61. Coat the inner wall of the casting groove with a release agent; S62. Pour the liquid silicone into the casting groove to a first liquid level height; S63. Place the outer shell casting mold in a vacuum autoclave and evacuate the vacuum autoclave until no air bubbles are discharged from the liquid silicone in the casting groove, then stop evacuating; S64. Open the vacuum autoclave, pour the liquid silicone into the casting groove until the liquid silicone flows into the overflow groove from the overflow hole, then stop; S65. Continue to evacuate the vacuum autoclave until no bubbles float out from the liquid silicone in the casting groove, then stop; S66. Take out the outer shell casting mold in the vacuum autoclave and put it into an incubator for constant temperature cooling.

Images