Insulation pouring structure between high-voltage coil and low-voltage coil of water-cooled dry-type transformer and manufacturing process of insulation pouring structure
By wrapping multi-layer insulating material on the surface of the low-voltage coil of the water-cooled dry transformer and casting resin together with the high-voltage coil to form, the problems of poor heat dissipation effect and excessive material use in traditional water-cooled dry transformers are solved. Achieve more efficient heat dissipation and production efficiency.
Patent Information
- Application Number
- CN202411610293.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-02-07
AI Technical Summary
In traditional water-cooled dry transformers, the heat dissipation effect of the high-voltage coil is poor. The separate separation structure between the high-voltage coil and the low-voltage coil leads to excessive use of copper wire materials, high cost, increased magnetic leakage, and low production efficiency.
A water-cooled dry-type transformer has been designed to insulating casting structure between high and low voltage coils. By wrapping multiple layers of insulating materials on the surface of the low voltage coil, including resin cloth, grid cloth and glass wire cloth, and casting resin together with the high voltage coil and the low voltage coil into molding. , realize the manufacturing process of insulated casting structure.
It improves the heat dissipation effect of high-voltage coils, reduces material use and magnetic leakage, reduces production costs, simplifies production processes, and improves production efficiency.
Smart Images
Figure CN119400566A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of water-cooled dry-type transformers, in particular to an insulating casting structure between high- and low-voltage coils of a water-cooled dry-type transformer and a manufacturing process thereof. Background Art
[0002] Dry-type transformer is a special type of transformer, which mainly works on the principle of magnetic induction and electromagnetic induction. Water-cooled dry-type transformer is a special form of dry-type transformer, which is designed to enhance the heat exchange rate by cleverly laying water pipes and improving insulation sealing, thereby improving the heat dissipation effect and the load working capacity of the transformer. The high-voltage coil and the low-voltage coil of the traditional high- and low-voltage transformer are separated into a structure, in which the low-voltage coil can be cooled by water cooling, and the high-voltage coil is cooled by air self-cooling or forced air cooling. However, the traditional water-cooled dry-type transformer still has shortcomings. First, in the traditional water-cooled dry-type transformer, the heat dissipation effect of the high-voltage coil is The heat dissipation performance of the low-voltage coil is not good, and the good heat dissipation performance of the low-voltage coil cannot be utilized; secondly, in the traditional water-cooled dry transformer, the high-voltage coil and the low-voltage coil adopt a separate separation structure, which leads to the use of more copper wire materials for the high-voltage coil, which is more expensive, and when the spacing is large, it will increase the leakage magnetic field, affecting the economic benefits; thirdly, in the traditional water-cooled dry transformer, the high-voltage and low-voltage coils must be cast separately, and then the high-voltage coil is put on the outer ring of the low-voltage coil. The high-voltage coil and the low-voltage coil must also be fixed to ensure that the two are fixed within the insulation spacing range, and the production efficiency is low; therefore, it is very necessary to design the insulation casting structure between the high and low voltage coils of the water-cooled dry transformer and its manufacturing process. Summary of the invention
[0003] The object of the present invention is to provide an insulating casting structure between high and low voltage coils of a water-cooled dry-type transformer and a manufacturing process thereof, so as to solve the problems raised in the above background technology.
[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solution: an insulating casting structure between high and low voltage coils of a water-cooled dry-type transformer, comprising a low voltage coil, on which a first resin cloth in a functional component is tightly attached, on which a first mesh cloth is tightly attached, on which a first mesh cloth is tightly attached, on which a first glass cloth is tightly attached, on which a second resin cloth is tightly attached, on which a second resin cloth is tightly attached, on which a second mesh cloth is tightly attached, on which a second glass cloth is tightly attached, on which a third resin cloth is tightly attached, on which a third mesh cloth is tightly attached, and on which a third mesh cloth is tightly attached.
[0005] As a further technical solution of the present invention, the functional component consists of a first resin cloth, a first mesh cloth, a first glass fiber cloth, a second resin cloth, a second mesh cloth, a second glass fiber cloth, a third resin cloth, a third mesh cloth and a third glass fiber cloth, and a high-voltage coil is tightly attached to the third glass fiber cloth.
[0006] The manufacturing process of the insulating casting structure between the high and low voltage coils of the water-cooled dry-type transformer comprises the following steps: step 1, winding the low voltage coil; step 2, setting the insulating structure; step 3, resin casting and molding; In the above step 1, the low voltage coil is wound and formed according to the traditional process for standby use; In the above step 2, the functional components are arranged on the low-voltage coil according to the design plan; In the above step three, the high-voltage coil, the functional components and the low-voltage coil are cast together with resin.
[0007] As a further technical solution of the present invention, in the step one, a winding mold is prepared, which is selected and adjusted according to the size and shape of the coil; the wire is cut into an appropriate length, and pre-treated such as deoxidation and coating with insulating paint; one end of the wire is fixed on the winding mold, and then winding is started. During the winding process, the tension and speed of the wire are kept stable to ensure the tightness and uniformity of the coil. After the winding is completed, the other end of the wire is fixed and welded to form a complete coil structure, and the coil is visually inspected to ensure that there is no damage or defect, thereby completing the winding and forming of the low-voltage coil.
[0008] As a further technical solution of the present invention, in the step 2, a layer of first resin cloth is wrapped on the surface of the low-voltage coil after winding, the thickness of the first resin cloth ranges from 0.3mm to 0.5mm, and the insulation level of the first resin cloth is Class A insulation or above.
[0009] As a further technical solution of the present invention, in the step 2, a first mesh cloth is then wrapped around the outer layer of the first resin cloth, the first mesh cloth is made of alkali-resistant glass fiber mesh cloth, and its thickness range is 0.14mm to 0.8mm; then a first glass fiber cloth is wrapped around the outer layer of the first mesh cloth, and the thickness range of the first glass fiber cloth is 0.1mm to 0.3mm, thereby completing the construction of the first insulation layer.
[0010] As a further technical solution of the present invention, in step 2, a second resin cloth, a second mesh cloth, a second glass cloth, a third resin cloth, a third mesh cloth and a third glass cloth are sequentially wrapped on the first glass cloth after wrapping.
[0011] As a further technical solution of the present invention, in the step 2, the material and thickness of the second resin cloth and the third resin cloth are the same as those of the first resin cloth, the material and thickness of the second mesh cloth and the third mesh cloth are the same as those of the first mesh cloth, and the material and thickness of the second glass fiber cloth and the third glass fiber cloth are the same as those of the first glass fiber cloth, thereby completing the construction of a total of three layers of insulation layers and completing the setting of functional components, and the thickness of the total insulation layer is 2mm to 4mm.
[0012] As a further technical solution of the present invention, in the step three, a high-voltage coil is wound on the third glass fiber cloth, and the low-voltage coil, functional components and high-voltage coil are loaded into a resin mold together, and poured in a vacuum box. First, the mold with the coil is heated to 80°C in the vacuum box as a whole and maintained at a constant temperature. When the vacuum degree is less than -0.099Mpa, resin is poured to the mold height. The resin model used is JT8068A / B.
[0013] As a further technical solution of the present invention, in the step three, after the vacuum degree is less than -0.099Mpa and maintained for 3 hours, the air is slowly released and the pressure is increased by 0.4-0.5Mpa, the pressure is maintained at 0.4-0.5Mpa for 1 hour and then slowly released, and then the vacuum is drawn to less than -0.099Mpa, the temperature is kept at 80°C for 1-2 hours and then slowly released, and then the pressure is increased by 0.4-0.5Mpa for 1 hour, the pressure is maintained at 0.4-0.5Mpa and the temperature is increased by 100°C for 4 hours and slowly released to normal pressure, the normal pressure is maintained and the temperature is increased to 130°C, and the temperature is maintained for 10 hours and then demolded after natural cooling.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the insulating casting structure between the high and low voltage coils of the water-cooled dry-type transformer and its manufacturing process, a layer of first resin cloth is wrapped on the surface of the low voltage coil after winding and forming, the thickness of the first resin cloth is in the range of 0.3mm to 0.5mm, and the insulation level of the first resin cloth is Class A insulation or above; then a layer of first mesh cloth is wrapped on the outer layer of the first resin cloth, the first mesh cloth adopts alkali-resistant glass fiber mesh cloth, and its thickness range is 0.14mm to 0.8mm; then a layer of first glass fiber cloth is wrapped on the outer layer of the first mesh cloth, the thickness of the first glass fiber cloth is in the range of 0.1mm to 0.3mm, and the construction of the first insulation layer is completed, and the second resin cloth, the second mesh cloth, the second glass fiber cloth, the third resin cloth, the third mesh cloth and the third glass fiber cloth are wrapped in sequence on the first glass fiber cloth after the wrapping is completed; wherein the material and thickness of the second resin cloth and the third resin cloth are the same as those of the first resin cloth, the material and thickness of the second mesh cloth and the third mesh cloth are the same as those of the first mesh cloth, and the second glass fiber cloth and the third glass fiber cloth are the same as those of the first mesh cloth. The material and thickness are the same as the first glass cloth, so as to complete the construction of a total of three layers of insulation layers, complete the setting of functional components, and the thickness of the total insulation layer is 2mm~4mm. The high-voltage coil is wound on the third glass cloth. Since the insulation thickness between the high-voltage coil and the low-voltage coil is very thin, only 2mm~4mm, after resin casting, the high-voltage coil and the low-voltage coil have a good heat transfer effect, and the low-voltage coil can adopt the water cooling method of copper pipe water passing, and the low-voltage coil has a strong cooling effect. After the heat of the high-voltage coil is transferred to the low-voltage coil through the bonding layer, a good heat dissipation and cooling effect is achieved through the low-voltage coil; due to the more fitted structure of the high-voltage coil and the low-voltage coil, the circumference of the high-voltage coil winding becomes smaller, so the material of the high-voltage coil is reduced, the spacing between them becomes smaller, the leakage magnetic flux will also be reduced, and the economic benefit is also higher; the low-voltage coil, the functional component and the high-voltage coil are jointly loaded into the resin mold for casting and demoulding, and the high-voltage coil and the low-voltage coil are cast together. Compared with the traditional high-voltage coil and the low-voltage coil are cast separately and then assembled, the overall production process is simpler and the production efficiency is higher. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 for Figure 1 A magnified view of the local structure of the middle A area; Figure 3 It is a partial structural cross-sectional schematic diagram of the present invention; Figure 4 for Figure 3 A magnified view of the local structure of the middle B area; Figure 5 is a flow chart of the method of the present invention; In the figure: 1. low-voltage coil; 2. functional component; 3. high-voltage coil; 21. first resin cloth; 22. first mesh cloth; 23. first glass cloth; 24. second resin cloth; 25. second mesh cloth; 26. second glass cloth; 27. third resin cloth; 28. third mesh cloth; 29. third glass cloth. DETAILED DESCRIPTION
[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0017] Please see attached Figure 1 -Attached Figure 4 An embodiment of the present invention provides: an insulating casting structure between high and low voltage coils of a water-cooled dry-type transformer, comprising a low voltage coil 1, a first resin cloth 21 in a functional component 2 is closely attached to the low voltage coil 1, a first mesh cloth 22 is closely attached to the first resin cloth 21, a first glass cloth 23 is closely attached to the first mesh cloth 22, a second resin cloth 24 is closely attached to the first glass cloth 23, a second mesh cloth 25 is closely attached to the second resin cloth 24, a second glass cloth 26 is closely attached to the second mesh cloth 25, a third resin cloth 27 is closely attached to the second glass cloth 26, a third mesh cloth 28 is closely attached to the third resin cloth 27, a third glass cloth 29 is closely attached to the third mesh cloth 28, and a functional component 2 is provided. Component 2 is composed of a first resin cloth 21, a first mesh cloth 22, a first glass fiber cloth 23, a second resin cloth 24, a second mesh cloth 25, a second glass fiber cloth 26, a third resin cloth 27, a third mesh cloth 28 and a third glass fiber cloth 29. A high-voltage coil 3 is tightly attached to the third glass fiber cloth 29. The high-voltage coil 3 is fixedly connected to the resin part. The functional component 2 is fixedly connected to the resin part. One end of the resin part is fixedly connected to the upper clamp, and the other end of the resin part is fixedly connected to the lower clamp. The lower clamp is fixedly connected to a base, and the base is fixedly connected to a traction plate. The upper clamp is fixedly connected to a lifting ring, and the upper clamp is fixedly connected to a conductive bar. The resin part is fixedly connected to a low-voltage coil 1.
[0018] Please see attached Figure 5 , an embodiment provided by the present invention: a manufacturing process of an insulating casting structure between high and low voltage coils of a water-cooled dry-type transformer, comprising the following steps: step one, winding a low voltage coil; step two, setting an insulating structure; step three, resin casting molding; In the above step 1, the low-voltage coil 1 is wound and formed according to the traditional process for standby use, and a winding mold is prepared, which is selected and adjusted according to the size and shape of the coil; the wire is cut into an appropriate length, and pre-treated by deoxidation, coating with insulating paint, etc.; one end of the wire is fixed on the winding mold, and then the winding is started. During the winding process, the tension and speed of the wire must be kept stable to ensure the tightness and uniformity of the coil. After the winding is completed, the other end of the wire is fixed and welded to form a complete coil structure, and the coil is visually inspected to ensure that there is no damage or defect, and the winding and forming of the low-voltage coil 1 is completed; In the above step 2, the functional component 2 is arranged on the low-voltage coil 1 according to the design scheme, and a layer of first resin cloth 21 is wrapped on the surface of the low-voltage coil 1 after winding. The thickness of the first resin cloth 21 ranges from 0.3mm to 0.5mm, and the insulation level of the first resin cloth 21 is Class A insulation or above; then a layer of first mesh cloth 22 is wrapped on the outer layer of the first resin cloth 21, and the first mesh cloth 22 is made of alkali-resistant glass fiber mesh cloth, and its thickness ranges from 0.14mm to 0.8mm; then a layer of first glass fiber cloth 23 is wrapped on the outer layer of the first mesh cloth 22, and the thickness of the first glass fiber cloth 23 ranges from 0.1mm to 0.3mm, completing the first insulation The second resin cloth 24, the second mesh cloth 25, the second glass cloth 26, the third resin cloth 27, the third mesh cloth 28 and the third glass cloth 29 are sequentially wrapped on the first glass cloth 23 after wrapping; wherein the material and thickness of the second resin cloth 24 and the third resin cloth 27 are the same as those of the first resin cloth 21, the material and thickness of the second mesh cloth 25 and the third mesh cloth 28 are the same as those of the first mesh cloth 22, and the material and thickness of the second glass cloth 26 and the third glass cloth 29 are the same as those of the first glass cloth 23, thereby completing the construction of a total of three layers of insulation layers, completing the setting of the functional component 2, and the thickness of the total insulation layer is 2mm to 4mm; In the above step three, the high-voltage coil 3, the functional component 2 and the low-voltage coil 1 are cast with resin together, the high-voltage coil 3 is wound on the third glass cloth 29, and the low-voltage coil 1, the functional component 2 and the high-voltage coil 3 are loaded into the resin mold together, and the casting is carried out in a vacuum box. First, the coil mold is heated to 80°C in the vacuum box as a whole and kept at a constant temperature. When the vacuum degree is less than -0.099Mpa, the resin is cast to the mold height. The resin model used is JT8068A / B; the vacuum degree is less than -0.099 After maintaining below Mpa for 3 hours, slowly release the air and increase the pressure to 0.4~0.5Mpa, maintain the pressure at 0.4~0.5Mpa for 1 hour and then slowly release the air, then evacuate to less than -0.099Mpa, maintain a constant temperature of 80℃ for 1~2 hours and then slowly release the air, then increase the pressure to 0.4~0.5Mpa for 1 hour, maintain the pressure at 0.4~0.5Mpa and increase the temperature to 100℃ for 4 hours, slowly release the air to normal pressure, maintain the normal pressure and increase the temperature to 130℃, maintain for 10 hours, then naturally cool and demold.
[0019] Working principle: When in use, a first resin cloth 21 is wrapped on the surface of the wound low-voltage coil 1. The thickness of the first resin cloth 21 ranges from 0.3mm to 0.5mm, and the insulation level of the first resin cloth 21 is Class A insulation or above; then a first mesh cloth 22 is wrapped on the outer layer of the first resin cloth 21. The first mesh cloth 22 is made of alkali-resistant glass fiber mesh cloth with a thickness range of 0.14mm to 0.8mm; then a first glass fiber cloth 23 is wrapped on the outer layer of the first mesh cloth 22. The thickness of the first glass fiber cloth 23 ranges from 0.1 mm~0.3mm, the first insulating layer is constructed, and the second resin cloth 24, the second mesh cloth 25, the second glass cloth 26, the third resin cloth 27, the third mesh cloth 28 and the third glass cloth 29 are sequentially wrapped on the first glass cloth 23 after wrapping; wherein the material and thickness of the second resin cloth 24 and the third resin cloth 27 are the same as those of the first resin cloth 21, the material and thickness of the second mesh cloth 25 and the third mesh cloth 28 are the same as those of the first mesh cloth 22, and the material and thickness of the second glass cloth 26 and the third glass cloth 29 are the same as those of the first mesh cloth 23. The first glass cloth 23 is the same, so as to complete the construction of a total of three layers of insulation layers, complete the setting of the functional component 2, and the thickness of the total insulation layer is 2mm~4mm. The high-voltage coil 3 is wound on the third glass cloth 29. Since the insulation thickness between the high-voltage coil 3 and the low-voltage coil 1 is very thin, only 2mm~4mm, after resin casting, the high-voltage coil 3 and the low-voltage coil 1 have a good heat transfer effect, and the low-voltage coil 1 can adopt the water cooling method of copper pipe water flow, and the low-voltage coil 1 has a strong cooling effect. The heat of the high-voltage coil 3 is transferred to the low-voltage coil through the bonding layer. After coil 1, a good heat dissipation and cooling effect is achieved through the low-voltage coil 1; due to the more fitted structure of the high-voltage coil 3 and the low-voltage coil 1, the circumference of the high-voltage coil 3 winding becomes smaller, so the material of the high-voltage coil 3 is reduced, the spacing between them becomes smaller, the leakage magnetic flux will also be reduced, and the economic benefit is also higher; the low-voltage coil 1, the functional component 2 and the high-voltage coil 3 are jointly loaded into the resin mold for casting and then demolding. The high-voltage coil 3 is cast together with the low-voltage coil 1. Compared with the traditional high-voltage coil 3 and the low-voltage coil 1, which are cast separately and then assembled, the overall production process is simpler and the production efficiency is higher.
[0020] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.
Claims
1. A casting structure for insulating high and low voltage coils of a water-cooled dry-type transformer, comprising a low voltage coil (1), characterized in that: The low-voltage coil (1) is closely attached to a first resin cloth (21) in the functional component (2); the first resin cloth (21) is closely attached to a first mesh cloth (22); the first mesh cloth (22) is closely attached to a first glass cloth (23); the first glass cloth (23) is closely attached to a second resin cloth (24); the second resin cloth (24) is closely attached to a second mesh cloth (25); the second mesh cloth (25) is closely attached to a second glass cloth (26); the second glass cloth (26) is closely attached to a third resin cloth (27); the third resin cloth (27) is closely attached to a third mesh cloth (28); and the third mesh cloth (28) is closely attached to a third glass cloth (29).
2. The insulating casting structure between high and low voltage coils of a water-cooled dry-type transformer according to claim 1 is characterized in that: The functional component (2) is composed of a first resin cloth (21), a first mesh cloth (22), a first glass cloth (23), a second resin cloth (24), a second mesh cloth (25), a second glass cloth (26), a third resin cloth (27), a third mesh cloth (28) and a third glass cloth (29), wherein the high-voltage coil (3) is closely attached to the third glass cloth (29).
3. The manufacturing process of the insulating casting structure between the high and low voltage coils of the water-cooled dry-type transformer comprises the following steps: Step 1: winding the low voltage coil; Step 2: setting the insulation structure; Step 3: resin casting; In the above step 1, the low-voltage coil (1) is wound and formed according to a conventional process for standby use; In the above step 2, the functional component (2) is arranged on the low-voltage coil (1) according to the design plan; In the above step three, the high-voltage coil (3), the functional component (2) and the low-voltage coil (1) are cast together with resin to form a mold.
4. The manufacturing process of the high- and low-voltage coil insulation casting structure of the water-cooled dry-type transformer according to claim 3 is characterized in that: In the step 1, a winding mold is prepared, and the winding mold is selected and adjusted according to the size and shape of the coil; the wire is cut into an appropriate length and pre-treated by deoxidation, coating with insulating paint, etc.; one end of the wire is fixed on the winding mold, and then winding is started. During the winding process, the tension and speed of the wire are kept stable to ensure the tightness and uniformity of the coil. After the winding is completed, the other end of the wire is fixed and welded to form a complete coil structure, and the coil is visually inspected to ensure that there is no damage or defect, thereby completing the winding and forming of the low-voltage coil (1).
5. The manufacturing process of the high- and low-voltage coil insulation casting structure of the water-cooled dry-type transformer according to claim 3 is characterized in that: In the second step, a layer of first resin cloth (21) is wrapped on the surface of the wound low-voltage coil (1), the thickness of the first resin cloth (21) is in the range of 0.3 mm to 0.5 mm, and the insulation level of the first resin cloth (21) is Class A insulation or above.
6. The manufacturing process of the high- and low-voltage coil insulation casting structure of the water-cooled dry-type transformer according to claim 3 is characterized in that: In the step 2, a first mesh cloth (22) is then wrapped around the first resin cloth (21), the first mesh cloth (22) being an alkali-resistant glass fiber mesh cloth with a thickness ranging from 0.14 mm to 0.8 mm; and a first glass fiber cloth (23) is then wrapped around the first mesh cloth (22), the thickness of the first glass fiber cloth (23) being in the range of 0.1 mm to 0.3 mm, thereby completing the construction of the first insulation layer.
7. The manufacturing process of the high- and low-voltage coil insulation casting structure of the water-cooled dry-type transformer according to claim 3 is characterized in that: In the second step, the second resin cloth (24), the second mesh cloth (25), the second glass cloth (26), the third resin cloth (27), the third mesh cloth (28) and the third glass cloth (29) are sequentially wrapped on the first glass cloth (23).
8. The manufacturing process of the high- and low-voltage coil insulation casting structure of the water-cooled dry-type transformer according to claim 3 is characterized in that: In the step 2, the material and thickness of the second resin cloth (24) and the third resin cloth (27) are the same as those of the first resin cloth (21), the material and thickness of the second mesh cloth (25) and the third mesh cloth (28) are the same as those of the first mesh cloth (22), and the material and thickness of the second glass cloth (26) and the third glass cloth (29) are the same as those of the first glass cloth (23), thereby completing the construction of a total of three layers of insulation layers and completing the setting of the functional component (2), and the thickness of the total insulation layer is 2 mm to 4 mm.
9. The manufacturing process of the high- and low-voltage coil insulation casting structure of the water-cooled dry-type transformer according to claim 3 is characterized in that: In the step three, a high-voltage coil (3) is wound on the third glass fiber cloth (29), and the low-voltage coil (1), the functional component (2) and the high-voltage coil (3) are placed together in a resin mold and poured in a vacuum box. The mold containing the coil is first heated to 80° C. in the vacuum box and kept at a constant temperature. When the vacuum degree is less than -0.099 MPa, resin pouring to the mold height is started. The resin model used is JT8068A / B.
10. The manufacturing process of the high- and low-voltage coil insulation casting structure of the water-cooled dry-type transformer according to claim 3, characterized in that: In the step three, after the vacuum degree is maintained below -0.099 MPa for 3 hours, the air is slowly released and the pressure is increased by 0.4-0.5 MPa, the pressure is maintained at 0.4-0.5 MPa for 1 hour and then slowly released, and then the vacuum is drawn to less than -0.099 MPa, the constant temperature is maintained at 80°C for 1-2 hours and then slowly released, and then the pressure is increased by 0.4-0.5 MPa for 1 hour, the pressure is maintained at 0.4-0.5 MPa, the temperature is increased by 100°C for 4 hours, and the air is slowly released to the normal pressure state, the normal pressure state is maintained and the temperature is increased to 130°C, and the temperature is maintained for 10 hours, and then the mold is demolded after natural cooling.