A method for manufacturing a pressure-resistant, lightweight, heat-resistant, and non-cutting magnetic field line protective cover

Abstract

The present invention discloses a method for making a pressure-resistant, lightweight, heat-resistant, and non-cutting magnetic line protective cover, which belongs to the technical field of protective covers. Its material composition includes: 40 to 50 parts by weight of resin, 15 to 25 parts by weight of curing agent, 45 to 55 parts by weight of inorganic fiber, and 3 to 7 parts by weight of inorganic ceramic powder. The method for making the protective cover includes the processes of mold design and production, mold release agent selection, fiber weaving, heat-resistant resin preparation, heat-resistant resin coating, thermal curing, fine processing, inspection and packaging. The protective cover made by the present invention has excellent mechanical properties and heat resistance, and does not cut magnetic lines. It can be widely used in magnetic transmission devices, replace metal protective covers, resist impact, generate little heat under magnetic induction conditions, and can ensure the long-term and effective operation of devices such as magnetic pumps and magnetic compressors. The method for making the protective cover disclosed by the present invention has a clear process flow, is easy to realize automation, has high production efficiency, low production cost, and high product cost performance.

Description

Technical Field

[0001] The present invention relates to the technical field of protective covers, and more specifically, to a method for manufacturing a pressure-resistant, lightweight, heat-resistant protective cover that does not cut magnetic lines of force. Background Art

[0002] The protective cover is a key component that can prevent dust and foreign matter from entering the device, and prevent the leakage of the medium in the device. It is commonly seen in general mechanical equipment such as pumps and compressors. In order to ensure sufficient strength and high and low temperature resistance, metal materials are generally used to make protective covers, but it inevitably increases the total weight and energy consumption of the device, and the corrosion resistance is poor.

[0003] In recent years, magnetic transmission technology has been continuously improving, and the size of components is controllable and the structure is simple. There are more and more application fields where magnetic transmission replaces mechanical transmission. In scenarios such as ships and new energy vehicles, the weight and size of magnetic pumps and magnetic compressors must be strictly controlled within a certain range. The protective cover is mainly used between the inner and outer magnetic steels to prevent leakage of the medium. If metal materials are used, the magnetic lines may be cut, affecting the efficiency of magnetic transmission, and increasing the risk of magnetic induced heating. Therefore, a non-metallic protective cover that is pressure-resistant, lightweight, high-temperature resistant, and does not cut magnetic lines has become an urgent need in the fields of ships, weapons, aviation, and aerospace.

[0004] Patent No. CN201310485891.X discloses a combined protective cover for a lead screw guide rail of a wire cutting machine tool, which is mainly composed of a front outer protective cover, a left connecting protective cover, a rear outer protective cover, a right connecting protective cover, a front inner protective cover, a rear inner protective cover, a left slide rail, a right slide rail, a left slide rail mounting bent plate, a right slide rail mounting bent plate, a left spring and a right spring. The left slide rail is provided with a plurality of threaded holes, each of which is provided with a plurality of threaded holes, each of which is provided with a plurality of threaded holes. A left movable rail front bolt and a left movable rail rear bolt are installed so that the left movable rail is installed on the left slide rail mounting plate. A left static rail rear bolt and a left static rail front bolt are installed in the rear hole and the front hole of the two left static rail mounting bent plate through holes on the left static rail of the left slide rail and in the rear hole and the front hole of the two left slide rail mounting bent plate threaded holes on the left slide rail mounting bent plate, respectively, so that the left slide rail mounting bent plate is installed together with the left static rail. A left spring front end ring and a left spring rear end ring of the left spring are hung on the left spring front end ring hanging bolt and the left static rail rear bolt, respectively.

[0005] This patent has the advantages of good protection performance, no noise, easy installation and sensitive movement, but the protective cover is made of a combination of ordinary materials, has low strength, and does not consider high and low temperature resistance, so it cannot be used in magnetic transmission mechanisms with limited space.

[0006] Patent No. CN202121494064.3 discloses a high temperature protection cover for a magnetic pump, including a bottom plate, a fixing bolt is arranged on the outer wall of the bottom plate, a slide groove is provided inside the bottom plate, a positioning block is provided on the inner wall of the slide groove, a ventilation hole is provided in the middle of the bottom plate, the bottom plate is connected to the slide plate through the slide groove, the outer wall of the slide plate is provided with a positioning groove, a baffle is provided on the outer wall of the slide plate, a connecting block is welded on the outer wall of the baffle plate, a cooling fan is provided on the inner wall of the ventilation hole, a fixing ring is provided at the bottom of the bottom plate, and a rotating plate is provided inside the fixing ring. The utility model uses a slide plate, when it is necessary to protect the magnetic pump, the slide plate is slid upward to protect the outer wall of the magnetic pump, and then the baffle plate is fitted with the outer wall of the slide plate, so that the slide plate is fixed and the magnetic pump is sealed at the same time, so that the high temperature can be isolated from the outside to prevent the high temperature from damaging the magnetic pump and causing the magnetic pump to fail to operate normally.

[0007] Patent No. CN201921057795.4 discloses a high temperature protection cover for a magnetic pump, including a protection cover body, a heat conducting plate is glued on the inner wall of the protection cover body, a cooling water bag is connected to the outside of the heat conducting plate in sequence, a magnetic pump is arranged on the inner side of the protection cover body, a support is installed at the lower end of the magnetic pump, a slider is fixed at the lower end of the support, a track is laid at the lower end of the protection cover body, the slider is connected with the track, the inside of the protection cover body is correspondingly provided with a vacuum layer, a first insulation layer and a second insulation layer from the outside to the inside, and a cover plate is installed at one end of the protection cover body. The utility model solves the problem that the insulation effect of the magnetic pump protection cover is not good and the external high temperature easily affects the performance of the magnetic pump by arranging the protection cover body, the heat conducting plate, the cooling water bag, the track, the screw, the mounting plate, the slider, the temperature sensor and the transmission module.

[0008] The above two patents both install protective covers on the outside of the magnetic pump main unit, which are not used for the core part of the magnetic transmission. They do not consider the energy saving of the equipment and the problem of magnetic transmission efficiency, and therefore cannot be used as protective covers for magnetic transmission devices. Summary of the invention

[0009] 1. Technical issues to be solved

[0010] The purpose of the present invention is to provide a method for manufacturing a pressure-resistant, lightweight, heat-resistant, and non-cutting magnetic field line protective cover, so as to solve the problems of poor corrosion resistance, heavy weight, and easy cutting of magnetic field lines proposed in the above-mentioned background technology. The protective cover made by the present invention is made of non-metallic materials, has low density and high strength, can be used repeatedly under 150°C working conditions, is not easy to deform, will not cut magnetic field lines, and can be widely used in magnetic transmission devices.

[0011] 2. Technical solution

[0012] A method for manufacturing a pressure-resistant, lightweight, heat-resistant, and non-cutting magnetic field line protective cover, characterized in that it comprises the following materials:

[0013]

[0014] Preferably, the resin includes epoxy resin, phenolic resin, vinyl resin, etc., and one or more of them are selected when used, with a number average molecular weight ranging from 200 to 500.

[0015] Preferably, the curing agent includes aromatic polyamines, amino resins, dicyandiamide, etc., and one of them is selected when used, and the number average molecular weight ranges from 100 to 300.

[0016] Preferably, the inorganic fibers include glass fibers, carbon fibers, boron fibers, etc., one or more of which are selected when used, and the fiber diameter is 8 to 15 μm, and the fibers are continuous filaments.

[0017] Preferably, the inorganic ceramic powder includes silicon oxide, silicon nitride, titanium oxynitride, etc., and one or more of them are selected when used. The microscopic morphology of the ceramic powder is approximately round, the particle size is 25 to 150 nm, and the purity is greater than 98%.

[0018] Preferably, the production method comprises the following steps:

[0019] S1: Design and production of molds. The molds are designed according to the shape, size and material shrinkage ratio of the workpiece. The mold material is hot working die steel, and the mold cavity structure is the same as the workpiece structure.

[0020] S2: Selection of a release agent, wherein methyl silicone oil is selected as the release agent, the mold is placed in a closed and clean container, and the methyl silicone oil is evenly applied to the inner cavity wall of the outer mold and the outer wall of the inner mold for standby use.

[0021] S3: Fiber weaving, the manufacturing process is: around the outer wall of the inner mold coated with methyl silicone oil, the warp wires of different fibers are crossed above and below every two weft wires, and each weft wire is crossed above and below every two warp wires to form a mat-type twill braided fabric, the thickness of the braided fabric is 0.1-0.8mm, and the pore size is 0.1-0.6mm. Multiple layers can be woven according to actual needs.

[0022] S4: Preparation of heat-resistant resin, the preparation process of the heat-resistant resin is: select one or more of epoxy resin, phenolic resin and vinyl resin, when multiple resins are selected, mix them together in a certain proportion, add the mixture into a mechanical stirring kettle, stir at a speed of 50-100rpm, stir for 20-30min, and obtain mixture one for standby use. Weigh a certain weight of curing agent and add it to an ultrasonic stirring kettle, and add an appropriate proportion of inorganic ceramic powder, stir for 20-30min, and obtain mixture two for standby use. When the coating process can start, add mixture one and mixture two into a mechanical stirring kettle, stir at a speed of 100-200rpm, stir for 10-20min, and obtain a colloidal mixture three.

[0023] S5: coating of heat-resistant resin. The coating process of the heat-resistant resin is as follows: the mixture obtained in step 4 is evenly coated on the surface of the woven fabric obtained in step 3. The coating can be performed multiple times according to actual needs.

[0024] S6: heat curing, the heat curing process is: put the braided fabric coated in step 5 into the outer mold together with the inner mold, put the whole into the curing furnace, start heating, the heating rate is 120-150℃ / h, when the temperature reaches 100℃, keep warm for 30-70min, then continue heating, the heating rate is 100-120℃ / h, when the temperature reaches 200℃, keep warm for 40-80min, stop heating after the insulation, and demould when the temperature drops below 35℃. Let it stand for 48 hours for use.

[0025] S7: Finishing: According to the drawing requirements of the protective cover product, further finishing such as turning, milling, and grinding is performed to meet the requirements of product dimensional tolerance and surface finish, pending inspection and acceptance.

[0026] S8: Check the packaging, check the size and appearance of the protective cover product, observe whether there are bubbles, cracks, flash, burrs and other abnormalities on the surface, and arrange the packaging after confirming that there are no abnormalities.

[0027] Preferably, in step S4, the weight ratio of various resins is in the range of (epoxy resin: phenolic resin: vinyl resin): 7:2:1.

[0028] Preferably, in step S4, the frequency of ultrasonic stirring is 20-25 Khz.

[0029] Preferably, in step S4, mixture three must be used up within 10 to 30 minutes.

[0030] 3. Beneficial effects

[0031] Compared with the prior art, the advantages of the present invention are:

[0032] 1. The protective cover proposed by the present invention is made of non-metallic materials with low density (not higher than 2.5g / cm 3 ), high specific strength, on the basis of meeting the mechanical properties, can greatly reduce the weight of the protective cover body, reduce the energy consumption of the host equipment. In addition, the protective cover proposed by the present invention is used to isolate the internal and external magnetic steels, will not cut the magnetic lines of force, and will not generate additional magnetic induction heating while ensuring the normal operation of the magnetic mechanism, which can ensure the long-term safe operation of devices such as magnetic pumps and magnetic compressors.

[0033] 2. The protective cover proposed by the present invention is modified by adding high-hardness, corrosion-resistant ceramic powder. On the one hand, it can improve the surface hardness of the protective cover and resist scratches. On the other hand, it can improve the corrosion resistance of the protective cover and can be used in corrosive environments such as acids and alkalis. It has better adaptability than metal materials.

[0034] 3. The present invention proposes a method of multi-variety fiber, multi-directional positioning mixed weaving, according to the characteristics of each fiber, respectively exert its excellent performance, such as high strength and temperature resistance of carbon fiber, high hardness and high toughness of glass fiber, so as to ensure the high strength and impact resistance of the main skeleton of the protective cover. In addition, the multi-directional mixed weaving of fibers also has a more beneficial effect on the strength of the protective cover proposed by the present invention.

[0035] 4. The present invention proposes a method for producing a pressure-resistant, lightweight, heat-resistant, and non-cutting magnetic field line protective cover. The process flow is clear, and weaving, gluing, thermal curing, and finishing can all be automated. The production efficiency is high, which can greatly reduce the production cost of such protective cover products and is conducive to the large-scale promotion of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic flow chart of a method for manufacturing a pressure-resistant, lightweight, heat-resistant, and non-cutting magnetic field line protective cover according to the present invention;

[0037] Figure 2 The present invention is a schematic structural diagram of a pressure-resistant, lightweight, heat-resistant, and non-cutting magnetic field line protective cover. DETAILED DESCRIPTION

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] In the description of the present invention, “plurality” means two or more than two, unless otherwise clearly and specifically defined.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] See also Figure 1 , the present invention provides two implementation cases:

[0042] Implementation Case 1

[0043] This case study produced a pressure-resistant, lightweight, heat-resistant, non-cutting magnetic field line protective cover, which uses a single resin, a single ceramic powder, and two types of fibers, and is suitable for general magnetic transmission conditions. The specific production steps are as follows:

[0044] S101: Design and manufacture the inner mold and outer mold for shaping according to the shape and size of the workpiece and the material shrinkage ratio. Apply methyl silicone oil evenly on the outer cavity wall of the inner film and the inner cavity wall of the outer mold.

[0045] S201: Weigh a certain weight of inorganic fiber filaments, including 20 parts by weight of glass fiber filaments and 25 parts by weight of carbon fiber filaments, and weave them on the outer cavity wall of the inner membrane according to the pre-designed weaving process to ensure that the thickness of the first layer of the braid is 0.1 mm.

[0046] S301: Weigh a certain weight of aromatic polyamine and silicon oxide powder, put them into an ultrasonic stirring kettle, wherein the aromatic polyamine is 15 parts by weight and the silicon oxide powder is 4 parts by weight. Turn on the machine, set the ultrasonic frequency to 20KHZ, stir for 30 minutes, and obtain a mixture 1 for standby use.

[0047] S401: Weigh 45 parts by weight of epoxy resin and mixture 1, add them into a mechanical stirring kettle, stir at a speed of 100 rpm, stir for 20 minutes, and obtain a colloidal mixture 2 for standby use.

[0048] S501: Apply the above glue mixture evenly on the surface of the woven fabric. According to the actual strength and size requirements, the woven and glued fabric can be applied multiple times. Note: The second application can be performed only after the mixture has penetrated into the fabric.

[0049] S601: Put the above glued braided fabric and the inner mold into the outer mold, preliminarily shape it, and then put it into the curing furnace as a whole, start heating, heating speed 150℃ / h, when the temperature reaches 100℃, keep it warm for 40min, then continue heating, heating speed 120℃ / h, when the temperature reaches 200℃, keep it warm for 40min, stop heating after the insulation, and demould when the temperature drops below 35℃. Let it stand for 48 hours for use.

[0050] S701: After the protective cover blank is taken out, it is precisely processed to meet the requirements of size and finish. Observe whether there are bubbles, cracks, flash, burrs and other abnormalities on the surface. After the inspection is completed, a qualified protective cover product is obtained.

[0051] Example 2

[0052] This case study produced a pressure-resistant, lightweight, heat-resistant, and non-cutting magnetic field line protective cover, which uses two types of resins, two types of ceramic powders, and two types of fibers. It is suitable for magnetic transmission conditions with alternating pressure and highly corrosive media. The specific production steps are as follows:

[0053] S102: Design and manufacture the inner mold and outer mold for shaping according to the shape and size of the workpiece and the material shrinkage ratio, and evenly apply methyl silicone oil on the outer cavity wall of the inner film and the inner cavity wall of the outer mold.

[0054] S202: Weigh a certain weight of inorganic fiber filaments, including 27 parts by weight of glass fiber filaments and 18 parts by weight of boron fiber filaments, and weave them on the outer cavity wall of the inner membrane according to the pre-designed weaving process to ensure that the thickness of the first layer of the braid is 0.15 mm.

[0055] S302: Weigh a certain weight of epoxy resin and phenolic resin, add them into a mechanical stirring kettle, wherein the epoxy resin is 30 parts by weight and the phenolic resin is 10 parts by weight, and the stirring speed is 70 rpm to reach a mixed colloid 1.

[0056] S402: Weigh a certain weight of dicyandiamide, silicon oxide powder and titanium oxynitride powder, and put them into an ultrasonic stirring kettle, wherein 13 parts by weight of dicyandiamide, 2 parts by weight of silicon oxide powder and 2 parts by weight of titanium oxynitride powder are added. Turn on the machine, set the ultrasonic frequency to 20KHZ, stir for 30 minutes, and obtain a mixture II for standby use.

[0057] S502: Add mixture 1 and mixture 2 into the mechanical stirring kettle successively, stirring at a speed of 150 rpm for 20 min to obtain a colloidal mixture 3 for standby use.

[0058] S602: Apply the above glue mixture evenly on the surface of the woven fabric. According to the actual strength and size requirements, the woven fabric can be woven and glued multiple times. Note: The second coating can be performed only after the mixture is soaked into the fabric.

[0059] S702: Put the above glued braided fabric and the inner mold into the outer mold together, preliminarily shape it, and then put it into the curing furnace as a whole, start heating, heating speed 120℃ / h, when the temperature reaches 100℃, keep it warm for 50min, then continue heating, heating speed 100℃ / h, when the temperature reaches 200℃, keep it warm for 60min, stop heating after the insulation ends, demould when the temperature drops below 35℃, and let it stand for 48 hours.

[0060] S802: After the protective cover blank is taken out, it is precisely processed to meet the requirements of size and finish. Observe whether there are bubbles, cracks, flash, burrs and other abnormalities on the surface. After the inspection is completed, a qualified protective cover product is obtained.

[0061] In summary: Implementation Case 2 uses two resins and two ceramic powders at the same time, and the protective cover product produced has better impact resistance and corrosion resistance, and higher surface hardness. In certain special fields, such as the discontinuous discharge of gas or liquid media, it has better adaptability. Therefore, the protective cover made of multiple fiber varieties, multiple resin varieties, and multiple ceramic powder varieties disclosed in the patent of this invention can meet the use requirements of different working conditions and has deeper and broader application prospects in the field of magnetic transmission.

[0062] The protective cover proposed by the present invention is made of non-metallic material with low density (no more than 2.5g / cm 3 ), high specific strength, on the basis of meeting the mechanical properties, can greatly reduce the weight of the protective cover body and reduce the energy consumption of the host equipment. The protective cover is used to isolate the internal and external magnetic steels, will not cut the magnetic lines of force, and will not generate additional magnetic induction heating while ensuring the normal operation of the magnetic mechanism, which can ensure the long-term safe operation of devices such as magnetic pumps and magnetic compressors. The addition of high-hardness, corrosion-resistant ceramic powder for modification can, on the one hand, improve the surface hardness of the protective cover and resist scratches, and on the other hand, improve the corrosion resistance of the protective cover. It can be used in corrosive environments such as acids and alkalis, and has better adaptability than metal materials. A method of mixed weaving of multiple varieties of fibers and multi-directional positioning is proposed. According to the characteristics of each fiber, its excellent performance is exerted respectively, such as the high strength and temperature resistance of carbon fiber, the high hardness and high toughness of glass fiber, etc., thereby ensuring the high strength and impact resistance of the main skeleton of the protective cover. In addition, the multi-directional mixed weaving of fibers also has a more beneficial effect on the strength of the protective cover proposed by the present invention. The process flow of the present invention is clear, and weaving, gluing, thermal curing and finishing can all be automated, with high production efficiency, which can greatly reduce the production cost of such protective cover products and is conducive to the large-scale promotion of the products.

[0063] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for making a pressure-resistant, lightweight, heat-resistant, and non-cutting magnetic field line protective cover. Features: The invention comprises the following materials: 35-45 parts by weight of resin, 15-25 parts by weight of curing agent, 40-55 parts by weight of inorganic fiber and 3-7 parts by weight of inorganic ceramic powder, wherein the resin comprises epoxy resin, phenolic resin and vinyl resin, one or more of which are selected when used, and the number average molecular weight ranges from 200 to 500, the curing agent comprises aromatic polyamine, amino resin and dicyandiamide, one of which is selected when used, and the number average molecular weight ranges from 100 to 300, the inorganic fiber comprises glass fiber, carbon fiber and boron fiber, one or more of which are selected when used, the fiber diameter is 8 to 15 μm, and the fiber is continuous filament, the inorganic ceramic powder comprises silicon oxide, silicon nitride and titanium oxynitride, one or more of which are selected when used, the microscopic morphology of the ceramic powder is approximately circular, the particle size is 25 to 150 nm, and the purity is greater than 98%; The production method comprises the following steps: S1: Mould design and production The mold is designed according to the shape, size and material shrinkage ratio of the workpiece. The mold material is hot working die steel, and the mold cavity structure is the same as the workpiece structure; S2: Selection of release agent The mold release agent is methyl silicone oil. The mold is placed in a closed and clean container, and the methyl silicone oil is evenly applied to the inner cavity wall of the outer mold and the outer wall of the inner mold for standby use. S3: Fiber weaving The fiber weaving process is as follows: surround the outer wall of the inner mold coated with methyl silicone oil, cross the warp wires of different fibers above and below every two weft wires, and cross each weft wire above and below every two warp wires to form a mat-type twill braided fabric with a thickness of 0.1 to 0.8 mm and a pore size of 0.1 to 0.6 mm; weave multiple layers according to actual needs; S4: Preparation of heat-resistant resin The preparation process of the heat-resistant resin is as follows: one or more of epoxy resin, phenolic resin and vinyl resin are selected, and when multiple resins are selected, they are mixed together in a certain proportion, and the mixture is added to a mechanical stirring kettle at a stirring speed of 50 to 100 rpm, and stirred for 20 to 30 minutes to obtain a mixture 1 for standby use; a certain weight of a curing agent is weighed and added to an ultrasonic stirring kettle, and an appropriate proportion of inorganic ceramic powder is added, and stirred for 20 to 30 minutes to obtain a mixture 2 for standby use; when the coating process can be started, the mixture 1 and the mixture 2 are added to the mechanical stirring kettle at a stirring speed of 100 to 200 rpm, and stirred for 10 to 20 minutes to obtain a colloidal mixture 3; S5: Heat-resistant resin coating The coating process of the heat-resistant resin is as follows: the mixture obtained in step S4 is uniformly coated on the surface of the braided fabric obtained in step S3, and the coating is performed multiple times according to actual needs; S6: Heat curing The heat curing process is as follows: the braided fabric coated in step S5 is loaded into the outer mold together with the inner mold, and the whole is placed in a curing furnace, and heating is started at a heating rate of 120-150°C / h. When the temperature reaches 100°C, it is kept warm for 30-70 minutes, and then the heating is continued at a heating rate of 100-120°C / h. When the temperature reaches 200°C, it is kept warm for 40-80 minutes. After the insulation is completed, the heating is stopped, and when the temperature drops below 35°C, it is demoulded; and it is left to stand for 48 hours for use; S7: Finishing The finishing process refers to further turning, milling and grinding according to the drawing requirements of the protective cover product to meet the requirements of product dimensional tolerance and surface finish, pending inspection and acceptance; S8: Check the packaging Check the size and appearance of the protective cover product, observe whether there are bubbles, cracks, flash, burrs or abnormalities on the surface, and pack it after confirming that there are no abnormalities.

2. A method for manufacturing a pressure-resistant, lightweight, heat-resistant, non-cutting magnetic field line protective cover according to claim 1, Features: In step S4, the weight ratio of epoxy resin:phenolic resin:vinyl resin is 7:2:

1.

3. A method for manufacturing a pressure-resistant, lightweight, heat-resistant, non-cutting magnetic field line protective cover according to claim 1, Features: In step S4, the frequency of ultrasonic stirring is 20-25 Khz.

4. A method for manufacturing a pressure-resistant, lightweight, heat-resistant, non-cutting magnetic field line protective cover according to claim 1, Features: In step S4, the mixture three must be used up within 10 to 30 minutes.

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