KR102405868B1 - FRP Flange manufactured by Infusion and Method thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing an FRP flange using a vacuum forming method and to an FRP flange manufactured by this method, wherein in the resin injection step, in order to maintain a constant negative pressure state in the inner space of a mold at a predetermined pressure, the main outlet is The ratio of the amount of discharged air per unit time discharged through the auxiliary outlet and the amount of discharged air per unit time discharged through the auxiliary outlet is 60 to 70%: 30 to 40% by maintaining the ratio, arbitrarily selected in the mold inner space in the decompression step and the resin injection step While minimizing the pressure difference between the two positions, the resin injected into the resin inlet is uniformly impregnated into the first, second, and third reinforcing materials stacked in the space for forming the body and the space for forming the expansion part of the inner space of the mold. It is characterized in that it becomes possible.

Description

FRP flange manufacturing method using vacuum forming method and FRP flange manufactured by this method {FRP Flange manufactured by Infusion and Method thereof}

The present invention relates to a method for manufacturing an FRP flange using a vacuum forming method and to an FRP flange manufactured by the method.

FRP (Fiber-reinforced plastic) is a plastic reinforced with fibers. In general, ducts and chemical tanks are used in semiconductor factories and chemical factories, etc. FRP (Fiber Reinforced Plastics) material with corrosion resistance is widely used.

In the case of constructing such an FRP pipe or FRP duct, an FRP flange is used to connect the ends of the two pipes to each other. The FRP flange for pipe connection has a body having a hollow part into which the end of the pipe is fitted, and an extension part having a cross section that is larger than the outer diameter of the body part.

Up to now, the forming and processing of FRP flanges has been made by hand lay-up process.

The present invention proposes a method of forming a FRP flange by infusion, which has features such as production of superior quality products and provision of a clean working environment compared to the manual lamination method, which is a conventional FRP forming and lamination method.

The vacuum molding method is one of the closed molding methods in which the molded product in operation is not exposed to the atmosphere, and is also called vacuum infusion (or bagging). As shown in Fig. 1, the principle of the vacuum molding method is to place a reinforcement material such as glass fiber in the mold that has been subjected to external release treatment, cover the vacuum vinyl, connect a vacuum pump, and apply a vacuum to the mold. It lowers the pressure inside the mold, connects the synthetic resin to the opposite side of the vacuum pump, and injects the synthetic resin into the mold using the pressure difference in the mold.

In general, the vacuum forming method (infusion) has the following characteristics compared to the manual forming method, which is a conventional glass fiber laminate forming method.

First, it is possible to secure an even strength. In the manual lamination method, the worker uses a roller to impregnate the synthetic resin and pressurize it to maintain the strength, so the quality depends on the worker's experience and skill. However, the vacuum forming method maintains the pressure inside the mold (mold) with a vacuum pump, so it can achieve equal strength.

Second, a beautiful surface finish is possible. In the manual lamination method, the surface of the opposite side of the mold is rough and the gel coat is applied after finishing. However, since the vacuum forming method uses a peel ply or a release film to make the surface opposite to the mold as if it has been polished, it is possible to reduce or omit the finishing operation.

Third, light weight and high strength products can be obtained. The manual lamination method has no choice but to maintain the ratio of synthetic resin to fiber at around 7:3 due to the limitations of manual work, whereas in the vacuum forming method, even if the ratio of synthetic resin to glass fiber (reinforcing material) is maintained up to about 3:7, the synthetic resin has a fibrous tissue. It can be evenly impregnated inside. In FRP molded products, if the content of synthetic resin is low, the thickness of the laminate becomes thinner and the product weight becomes lighter. Also, since the ratio of fibers can be increased, tensile strength and flexural strength can be increased.

However, since the vacuum molding method is impregnated in such a way that the synthetic resin is injected and the fiber reinforcement absorbs the synthetic resin, there is a high possibility that voids are generated inside the fiber reinforcement.

In particular, the FRP flange for pipe connection has a shape that is perpendicular to the body having a hollow part into which the pipe end is fitted, in which the expanded part (the wing part in which several fastening screw insertion holes are radially formed) having a cross section that is larger than the outer diameter of the body is perpendicular to the body. Due to the characteristics of the resin, not only the arrangement of the resin inlet and the air outlet is important, but also the lamination of the fiber reinforcement (glass fiber) is very important.

Korean Patent Registration No. 10-2176913 Korean Patent Registration No. 10-2325433 Korean Patent Registration No. 10-2288285 Republic of Korea Patent Publication No. 10-2020-0134525

The present invention has been devised to solve the above problems,

The purpose of this is to propose a method for forming FRP flanges by vacuum forming method (infusion), which has features such as production of superior quality products and provision of a clean working environment compared to the manual lamination method, which is the existing FRP forming lamination method.

In addition, the present invention relates to the shape of a flange at a right angle to a body having a hollow part into which an extension part (a wing part having a plurality of fastening screw insertion holes formed in a radial direction) having a cross section wider than the outer diameter of the body is fitted with a pipe end. By proposing a manufacturing method optimally suitable for aims to propose.

In order to achieve the above object, the FRP flange manufacturing method using the vacuum forming method according to the present invention,

In the method of forming an FRP flange for pipe connection, the body having a hollow part into which the end of the pipe is fitted, and an extension part having a cross-section wider than the outer diameter of the body part,

a first mold preparation step of installing a first mold 110 having an outer chin forming an outer rim of the extension part and a bottom part forming a lower end surface of the extension part;

a first reinforcing material stacking step of cutting and processing a first reinforcing material to correspond to the cross-sectional shape of the expanded portion and stacking the first reinforcing material on the first mold;

a second mold installation step of installing a second mold forming the hollow part of the body by seating it on the bottom of the first mold;

a second reinforcing material laminating step of laminating a second reinforcing material on an outer circumferential surface of the second mold perpendicular to the upper surface of the first reinforcing material;

a third reinforcing material laminating step of simultaneously stacking a third reinforcing material bent at right angles on the first reinforcing material stacked on the upper surface of the first mold and the second reinforcing material stacked on the outer circumferential surface of the second mold;

a mold sealing step of sealing a third mold coupled to the outer jaw of the first mold and forming an upper surface of the extension part and an outer surface of the body with the first mold and the second mold;

The resin supply valve of the connecting pipe connecting the synthetic resin container and the mold inner space formed by the first mold, the second mold, and the third mold is cut off, and the compressor is connected to the air outlet communicating with the mold inner space, and the air a decompression step of lowering the pressure in the inner space of the mold by opening the discharge valve;

Injecting the synthetic resin into the resin inlet by opening the resin supply valve of the connecting pipe connecting the synthetic resin container and the resin inlet communicating with the mold inner space formed by the first mold, the second mold, and the third mold step;

a curing step of stopping the decompression step and shutting off the resin supply valve when the set capacity of the synthetic resin is injected into the inner space of the mold, and maintaining it for about 1 to 2 hours;

After completion of the curing step, a demolding step of separating the first mold, the second mold, and the third mold to demold the product;

It characterized in that it comprises a post-processing step of processing the edge of the demolded product.

In particular, the resin inlet is formed in the third mold at a position spaced at equal intervals at a radial position with respect to the vertical central axis of the third mold,

The air outlet, the main outlet formed on the vertical central axis of the third mold, and the auxiliary outlet formed on the vertical central axis of the first mold, the amount of air discharged per unit time discharged through the main outlet and the ratio of the amount of exhaust air per unit time discharged through the auxiliary outlet is maintained at a ratio of 60 to 70%: 30 to 40%, thereby minimizing the pressure difference between two positions arbitrarily selected in the inner space of the mold in the decompression step and the resin injection step It is characterized in that the resin injected into the resin injection port is uniformly impregnated with the first reinforcing material, the second reinforcing material and the third reinforcing material stacked in the space for forming the body and the space for forming the extension part of the inner space of the mold.

Furthermore, in the present invention, a plurality of grooves communicating the inner space of the mold for molding the body and the main outlet are radially formed on the upper surface of the second mold or the inner surface of the third mold, in the decompression step It is characterized in that while the air in the inner space of the mold is discharged to the main outlet, the pressure difference between two positions arbitrarily selected in the inner space of the mold is minimized.

Another problem to be solved in the present invention and specific solutions thereof will be described in more detail in the 'Specific Contents for Carrying Out the Invention' and accompanying drawings to be described later.

By the FRP flange manufacturing method according to the present invention, it is possible to minimize the number of working people. That is, in the existing manual work (hand layup process), at least 4 to 6 people were input for each process, but in each step of the present invention, FRP flange manufacturing is possible with only two working people, so the labor cost of about 50% or more savings can be obtained.

And, in the existing manual work (hand layup process), it took at least 8 hours (including at least 3 hours for hardening) to produce one FRP flange.

According to the manufacturing method according to the present invention, it takes up to 3 hours (including at least 1 hour for hardening) to manufacture one FRP flange of the same size, so productivity can be increased by about 3 times .

Furthermore, in the existing manual work (hand layup process), the Choft Strand Mat is wetted with resin and wrapped around the mold to form the FRP flange. 'Surface post-processing' was required, but with the manufacturing method according to the present invention, resin is injected into the inner space of the mold to obtain a product of a certain thickness in the form of the inner space of the mold, so the time required for post-processing can be greatly reduced. have.

And, in the case of the existing manual work, the lamination time and curing time of the chop strand mat were greatly increased as the size of the product increased. Although cost is required, after the mold preparation is completed, large-scale production is possible with only a slight increase in the time required for lamination of the chopped strand mat and time for resin injection.

In addition, the FRP flange manufacturing method using the vacuum forming method according to the present invention is a hollow in which the end of the pipe is fitted with an extension (a wing portion in which a plurality of fastening screw insertion holes are formed radially) having an outer diameter that is larger than the outer diameter of the body. Considering the shape characteristics of the flange forming a right angle with respect to the body having the portion, a third reinforcing material having a bent portion bent at a right angle, the first reinforcing material stacked on the upper surface of the first reinforcing material and the second mold By laminating at the same time on the second reinforcing material laminated on the outer circumferential surface, the strength of the connection part of the extension part and the body is improved,

Furthermore, in the decompression step of discharging air from the inner space of the mold, separate from the main outlet in order to minimize voids that may be caused by non-uniformly impregnated resin in the molding process of the flange in which the extension is perpendicular to the body. to further form a plurality of auxiliary outlets, and to have a ratio of 60 to 70%: 30 to 40% of the amount of exhaust air discharged per unit time through the main outlet and the amount of air discharged per unit time discharged through the auxiliary outlet, thereby reducing the pressure In the step and the resin injection step, the reinforcing material is uniformly impregnated with the injected resin while minimizing the pressure difference between the two positions arbitrarily selected in the inner space of the mold, so that a high-quality FRP flange can be produced.

Another effect of the present invention will be described in more detail in the 'Specific details for carrying out the invention' to be described later.

1 is an explanatory diagram illustrating the basic principle of a vacuum forming method;
2 is an external view of the FRP flange to be manufactured by the present invention by the vacuum forming method.
3 is a perspective view of a mold as an embodiment of the FRP flange manufacturing method according to the present invention;
4 is a vertical cross-sectional view in the assembled state of the mold shown in FIG. 3;
5 is a photograph of a first mold according to an embodiment of the present invention;
6 is a photograph illustrating the step of stacking the first reinforcement material by cutting and processing the first reinforcement material in the FRP flange manufacturing method according to the present invention and stacking it on the first mold;
7 is a photograph taken of the second mold installation step;
8 and 9 are a third reinforcing material stacking step in which a third reinforcing material bent at a right angle is simultaneously laminated on the first reinforcing material stacked on the first mold and on the second reinforcing material stacked on the outer circumferential surface of the second mold. Photo
10 is a photograph illustrating a working step of alternately repeating the step of stacking the second reinforcing material 52 and the step of stacking the third reinforcing material 53 several times.
11 is a photo explaining the mold sealing step
12 is a photograph illustrating the injection step of injecting the synthetic resin into the resin injection port while depressurizing the mold inner space;

Since the present invention can have various changes and can have various forms, implementation examples (態樣, aspects) (or embodiments) will be described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

In addition, in each drawing, components are expressed in exaggeratedly large (or thick), small (or thin) or simplified in size or thickness in consideration of convenience of understanding, but the protection scope of the present invention is limited by this. it shouldn't be

The terminology used herein is only used to describe a specific embodiment (aspect, aspect, aspect) (or embodiment), and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present application, terms such as ~ comprises ~ or ~ consists of are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

~1~, ~2~, etc. described in the present specification are only to be referred to in order to distinguish that they are different components, and are not limited to the order of manufacture, and their names in the detailed description and claims of the invention are may not match.

In describing the FRP flange manufacturing method according to the present invention together with the accompanying drawings, if the approximate direction reference is specified with reference to FIG. 2 for convenience,

The direction of the central axis (z) of the inner hollow part 12 of the body 11 is defined as the 'up and down direction', and the direction away from the central axis (z) is 'outward' or outward, and the opposite direction is defined as the direction away from the central axis (z). referred to as 'medially' or medially. And in the detailed description and claims of the invention related to other drawings, unless otherwise specified, directions are specified and described according to this standard.

Hereinafter, the FRP flange manufacturing method using the vacuum forming method according to the present invention will be described in detail with reference to the accompanying drawings, mainly showing preferred embodiments.

First, Figure 2 shows a schematic external appearance of the FRP flange product manufactured by the FRP flange manufacturing method using the vacuum forming method according to the present invention. Although FIG. 2 shows an FRP flange having a cylindrical shape, it is natural that the manufacturing method according to the present invention can be applied to manufacturing a rectangular FRP flange.

As shown in FIG. 2 , the FRP flange 10 manufactured by the FRP flange manufacturing method using the vacuum forming method according to the present invention has a body 11 having a hollow part 12 into which the end of the pipe is fitted. ) and an extension 13 having an outer diameter that is larger than the outer diameter of the body 11 . The body 11 and the extension 13 form a right angle. A plurality of fastening holes 17 are formed in the extension part 13 at regular intervals from the central axis line z and radially. In addition, a protruding jaw 15 is formed in the inner direction of the extension part 13 . The body 11 may have a constant thickness in the vertical direction, but in order to secure rigidity at the connection part between the extension part and the body and to secure the ease of demolding, the thickness gradually decreases as it goes up from the extension part to the upper part. it is preferable

In order to manufacture the FRP flange of the same structure as the example shown in FIG. 2 by the vacuum forming method, as shown in FIG. 3 , the first mold 110 , the second mold 120 and the third mold 130 . Prepare a mold (mold) consisting of

The first mold 110 is a mold for molding the expanded portion 13 of the FRP flange, and an outer jaw 113 forming an outer rim of the expanded portion 13, and a lower end surface of the expanded portion A bottom portion 115 is provided. And, in the center of the bottom part 115 of the first mold 110 , the first mold 110 , the second mold 120 , and the third mold 130 , to remove air from the mold inner space. Auxiliary outlet 112 is further provided for. In FIG. 3 , reference numeral 117 denotes a protrusion formed on the first mold 110 to form a plurality of fastening holes 17 .

The second mold 120 is a mold for molding the hollow portion 12 of the FRP flange, and on the upper surface of the second mold, a plurality of first grooves 122a formed from the edge of the second mold toward the center. It is preferred that this is formed. And a protruding jaw forming part 125 for forming the protruding jaw 15 in the inward direction shown in FIG. 2 is provided at the lower portion of the second mold. The protruding jaw forming part 125 has a height and an outer diameter corresponding to the height and protrusion amount of the protruding jaw 15 . In addition, a plurality of second concave grooves 122b formed from the edge of the protruding chin forming part 125 toward the center are formed on the lower surface of the protruding chin forming part 125 .

The third mold 130 includes a wing part 131 coupled to the outer jaw of the first mold 110 to shape the upper surface of the extension part 13 , and a body part forming the outer surface of the body 11 . (132) is provided. In addition, the wing portion 131 of the third mold 130 is for injecting a resin into the mold inner space composed of the first mold 110 , the second mold 120 , and the third mold 130 . A plurality of resin injection holes 133 are formed. Each of the plurality of resin injection holes 133 is configured to be positioned at the same distance with respect to the central axis line z, and is preferably spaced apart from each other at equal intervals. For example, when it consists of two resin inlets 133, the imaginary line connecting the two resin inlets intersects the central axis line z, and is disposed at opposite positions.

And in the upper center of the third mold 130, the first mold 110, the second mold 120, and the main outlet 134 for removing air from the mold inner space composed of the third mold 130. ) is further provided. The main outlet 134 is preferably located on the central portion of the third mold 130 , that is, on the central axis line z, in order to have the same separation distance from the resin inlets 133 .

FIG. 4 is a vertical cross-sectional view showing the first mold 110, the second mold 120, and the third mold 130 shown in FIG. 3 in an assembled state.

As shown in FIG. 4, after the synthetic resin injected into the mold inner space is filled in the space to be molded by the expansion part 13, it is gradually moved upward and filled in the space to be molded, the FRP flange product to be molded. The height of the second mold 120 and the third mold 130 so that the height of the second mold 120 and the third mold 130 is slightly higher than the body height, that is, to have an additional height H. It is preferable to form By configuring in this way, accurate and uniform product molding is possible only with simple post-processing of the upper end of the body.

A method of manufacturing the FRP flange by the vacuum forming method using the first mold 110 , the second mold 120 and the third mold 130 described so far will be described.

3 or 5, prepare a first mold 110 having an outer jaw 113, a bottom part 115, and an auxiliary outlet 112 for venting air in the center of the bottom part ( 1st mold preparation step).

As a next step, as shown in FIG. 6 , the first reinforcing material 51 is processed and cut to correspond to the cross-sectional shape of the expanded part, and laminated on the first mold (first reinforcing material lamination step). A chopped strand mat is used as the first reinforcing material, and is cut to a size corresponding to the width of the extension to be formed, and a hole for accommodating the protrusion 117 is machined.

For reference, FIGS. 5 and 6 show a contact portion where the first mold 110 and the second mold 120 come into contact with each other, and a contact portion where the first mold 110 and the third mold 130 come into contact with each other. , as a photograph of each arrangement of the sealing member, the sealing member may be omitted, but it is more preferable to install the sealing member in order to improve sealing performance of the inner space of the mold in the depressurization step to be described later.

As a next step, as shown in FIG. 7 , the second mold 120 for molding the hollow part 12 of the body is seated on the bottom of the first mold 110 (second mold installation step) .

Then, a second reinforcing material 52 is laminated on the outer circumferential surface of the second mold having an outer circumferential surface perpendicular to the upper surface of the first reinforcing material 51 (second reinforcing material lamination step). Since the second reinforcing material 52 is made of woven roving glass fiber, it is possible to ensure smooth impregnation of the resin.

In the vacuum forming method, in a state in which the fiber reinforcement is laminated inside the mold, the synthetic resin flows by vacuum pressure to infiltrate the synthetic resin into the fiber reinforcement. do. The spacing ratio of the first and second reinforcing materials refers to the spacing between weaving fibers or fiber strands, and is usually about 0.5 to 0.85. Permeability refers to the degree of fluid flow of the fiber itself. In the FRP flange manufacturing method using the vacuum forming method according to the present invention, Woven Roving Glass Fiber was applied as the second reinforcing material 52 .

In the next step, in order to improve the strength of the connection portion of the body 11 forming a right angle with the extension 13, after bending the third reinforcing material 53 at a right angle, the horizontal surface of the first reinforcing material 51 is It is laminated on the upper surface and the vertical surface is laminated simultaneously on the second reinforcing material 52 laminated on the outer circumferential surface of the second mold (third reinforcing material lamination step). 8 and 9 are photographs for explaining the 'third reinforcement material stacking step' of laminating the third reinforcement material 53 . The third reinforcing material 53 increases the strength at the connection portion of the body forming a right angle with the extension by applying a chopped strand mat having a lower gap rate and lower permeability than the second reinforcing material 52 . can do.

In particular, in order to further strengthen the rigidity at the connection portion of the body forming a right angle with the extension, the step of stacking the second reinforcing material 52 and the step of stacking the third reinforcing material 53 are alternately repeated several times to form the FRP flange to be formed. It is preferable to laminate the reinforcing material to correspond to the thickness. 10 is a photograph illustrating a working step in which the second reinforcing material 52 stacking step and the third reinforcing material 53 stacking step are alternately repeated several times.

When the first reinforcing material stacking step, the second reinforcing material stacking step, and the third reinforcing material stacking step are completed, the third mold 130 is placed in the first mold 110 and the second mold ( 120) and sealed (mold sealing step).

As described above, in the first mold preparation step or the mold sealing step, the first mold 110 and the second mold 120 are in close contact with each other or the first mold 110 and the third mold (130) may further include a sealing member installation step of disposing each sealing member in close contact with each other.

The next step is to connect the resin supply valve 134 of the connecting pipe connecting the mold inner space formed by the first mold 110 , the second mold 120 , and the third mold 130 and the synthetic resin storage container to each other. The compressor is connected to the main outlet 134 for discharging air from the inner space of the mold in communication with the inner space of the mold, and the air outlet valve is opened to lower the pressure in the inner space of the mold (pressure reducing step). The degree of decompression in the decompression step is adjusted according to the size of the product to be molded, the gap rate and permeability of the reinforcing material, and the viscosity of the synthetic resin. and a third reinforcing material 53, woven roving glass fiber as a second reinforcing material, and a synthetic resin having a viscosity of 250 to 450 mPas is applied. Based on the example, about 0.08 to 0.09 MPa It was confirmed that optimal quality can be secured by forming a sound pressure of

In the decompression step, in order to form a uniform negative pressure over the entire inner space of the mold and at the same time prevent the occurrence of disorder of the reinforcing materials stacked in the decompression process, in the present invention, the main axis in the vertical direction of the third mold 130 is An outlet 134 is formed, and an auxiliary outlet 112 is further provided on the vertical central axis of the first mold 110 . 12 is a photograph illustrating an injection step of injecting a synthetic resin into a resin inlet while depressurizing the inner space of the mold, and reference numeral 112a in FIG. 12 is an air exhaust hose for discharging air through the auxiliary outlet 112 .

Then, a plurality of first grooves 122a formed from the edge of the second mold toward the main outlet 134 are formed on the upper surface of the second mold,

By forming a plurality of second concave grooves 122b formed toward the auxiliary outlet 112 from the edge of the protruding jaw forming part 125 also on the lower surface of the protruding jaw forming part 125 of the second mold,

It is preferable to sufficiently secure an air flow path between the mold inner space and the main outlet 134 and between the mold inner space and the auxiliary outlet 112 .

After the decompression step, the resin supply valve is opened to inject the synthetic resin into the mold inner space formed by the first mold 110 , the second mold 120 and the third mold 130 through the resin injection port 133 . Inject (resin injection step). The viscosity of the synthetic resin applied in this step was carried out by applying 350 mPas.

In the resin injection step, the design of the position of the resin injection port is very important. In a preferred embodiment of the present invention, the resin inlet 133 is formed in a position spaced at equal intervals in a radial position based on the vertical central axis of the third mold, so that the resin is discharged by the negative pressure of the inner space of the mold. Another feature is that it is uniformly and uniformly impregnated when it is impregnated into the reinforcing material while being injected into the mold.

In particular, it is particularly important to constantly maintain the negative pressure state of the inner space of the mold at about 0.08 to 0.09 MPa by continuing the decompression step in the resin injection step. In the present invention, for this, the ratio of the amount of exhaust air per unit time discharged through the main outlet and the amount of exhaust air per unit time discharged through the auxiliary outlet is 60 to 70%: 30 to 40% by maintaining the ratio of the decompression step and the resin In the injection step, the resin injected into the resin injection port while minimizing the pressure difference between two positions arbitrarily selected in the inner space of the mold in the injection step is laminated in the space for forming the body and the space for forming the extension part of the inner space of the mold, the first reinforcing material and the second It is characterized in that it is uniformly impregnated into the second reinforcing material and the third reinforcing material.

When the injection of the set capacity of the synthetic resin into the inner space of the mold is completed, the decompression step and the resin injection step are stopped, and a curing step of maintaining the resin for about 1 to 2 hours is performed.

After the curing step is completed, the first mold 110 , the second mold 120 , and the third mold 130 are separated, and a demolding step of demolding the product from the mold is performed.

As a final process, after a post-processing step of processing the edges of the demolded product, the FRP flange using the vacuum forming method according to the present invention is completed.

In the above description of the present invention, preferred embodiments have been mainly described with reference to the accompanying drawings, but the present invention is capable of various modifications, changes and substitutions by those skilled in the art, and these modifications, changes and substitutions are within the scope of protection of the present invention. should be construed as belonging to

10: FRP flange 11: body
12: hollow part 13: expanded part
110: first mold 112: auxiliary outlet
120: second mold 125: protruding jaw forming part
130: third mold 133: resin inlet
134: main outlet

Claims (4)

delete delete A method of forming an FRP flange for pipe connection having a body having a hollow portion into which an end of a pipe is fitted, and an extension having a cross-section that is larger than the outer diameter of the body,
a first mold preparation step of installing a first mold 110 having an outer chin forming an outer rim of the extension part and a bottom part forming a lower end surface of the extension part;
a first reinforcing material stacking step of cutting and processing a first reinforcing material to correspond to the cross-sectional shape of the expanded portion and stacking the first reinforcing material on the first mold;
a second mold installation step of installing a second mold forming the hollow portion of the body by seating it on the bottom of the first mold;
a second reinforcing material laminating step of laminating a second reinforcing material on an outer circumferential surface of the second mold perpendicular to the upper surface of the first reinforcing material;
a third reinforcing material laminating step of simultaneously laminating a third reinforcing material bent at right angles on the first reinforcing material stacked on the upper surface of the first mold and the second reinforcing material stacked on the outer circumferential surface of the second mold;
a mold sealing step of sealing a third mold coupled to the outer jaw of the first mold and forming an upper surface of the extension part and an outer surface of the body with the first mold and the second mold;
Block the resin supply valve of the connecting pipe connecting the synthetic resin container and the mold inner space formed by the first mold, the second mold, and the third mold, and connect the compressor to the air outlet communicating with the mold inner space, a decompression step of lowering the pressure in the inner space of the mold by opening the discharge valve;
By opening the resin supply valve of the connecting pipe connecting the synthetic resin container and the resin inlet communicating with the mold inner space formed by the first mold, the second mold, and the third mold, the synthetic resin is injected into the resin inlet. step;
a curing step of stopping the decompression step and shutting off the resin supply valve when the set capacity of the synthetic resin is injected into the inner space of the mold, and maintaining it for 1 to 2 hours;
After completion of the curing step, a demolding step of separating the first mold, the second mold, and the third mold to demold the product;
Including; a post-processing step of processing the edge of the demolded product

The second reinforcing material laminating step and the third reinforcing material laminating step are alternately repeated two or more times, but the first reinforcing material is a chopped strand mat, and the second reinforcing material is a woven roving glass fiber ), and the third reinforcing material is a chopped strand mat;

the resin inlet is formed in the third mold at positions spaced apart at equal intervals in a radial position with respect to the vertical central axis of the third mold;
the air outlet includes a main outlet 134 formed on the vertical central axis of the third mold and an auxiliary outlet 112 formed on the vertical central axis of the first mold;

In the decompression step, a negative pressure of 0.08 to 0.09 MPa is formed, but the ratio of the amount of exhaust air per unit time discharged through the main outlet 134 and the amount of exhaust air discharged through the auxiliary outlet 112 per unit time is 60 to 70 %: by controlling the ratio to be 30-40%, and maintaining a constant negative pressure state in the inner space of the mold;
The first reinforcing material and the second reinforcing material in which the resin injected in the injection step is laminated in the space for forming the body and the space for forming the expansion part of the inner space of the mold while minimizing the pressure difference between the two arbitrarily selected positions in the inner space of the mold. and a method for manufacturing an FRP flange using a vacuum forming method, characterized in that it is uniformly impregnated with the third reinforcing material.
An FRP flange manufactured by the manufacturing method of claim 3.

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