KR20230136309A - Injection molded product using metal insert part with FRP molded parts inserted and method for manufacturing the same - Google Patents

Abstract

The present invention relates to an injection molded product and a method of manufacturing the same, and more specifically, to a part of an insert member having a reinforcement structure formed by inserting an FRP molded body into an insertion space formed through bending instead of thinning the thickness of the metal insert member and reducing the number of bends. It relates to an injection molded product using a metal insert member inserted with an FRP molded body that can contribute to weight reduction and slimming of an electronic device by injection molding to form a resin layer that completely buries the same, and to a method of manufacturing the same.

Description

Injection molded product using metal insert part with FRP molded parts inserted and method for manufacturing the same}

The present invention relates to an injection molded product and a method of manufacturing the same, and more specifically, to a part of an insert member having a reinforcement structure formed by inserting an FRP molded body into an insertion space formed through bending instead of thinning the thickness of the metal insert member and reducing the number of bends. It relates to an injection molded product using a metal insert member inserted with an FRP molded body that can contribute to weight reduction and slimming of an electronic device by injection molding to form a resin layer that completely buries the same, and to a method of manufacturing the same.

In electronic devices, including mobile devices, with a display module on the front, a front case frame (or bracket) and a rear case frame are combined to form the exterior of the electronic device. It may be configured in such a way that the display module is exposed on the front of the case frame.

Front case frames are generally manufactured by injecting glass fiber-reinforced composite resin into a metal frame. However, in order to satisfy the mechanical performance with only a metal frame, there is a problem in that the thickness and weight of the metal frame increase, and as a result, the thickness of the product increases. increases and restrictions on design arise.

In addition, conventional methods have been used to increase the rigidity and strength of the final product by bending the metal frame, but there is a problem that the frame production time and cost increase as the number of bending increases.

As such, conventional electronic devices have the disadvantage that the overall weight and volume of the electronic device increases due to the front case frame or bracket, and in recent years, they have become lighter, shorter, and slimmer, which may run counter to the trend.

The matters described in the background art section above are written to improve understanding of the background of the invention, and may include matters that are not prior art already known to those skilled in the art in the field to which this technology belongs.

Patent Publication No. 10-2016-0132294

As a result of numerous studies to solve the above-mentioned problems, the present inventors completed the present invention by developing a metal frame designed to have a plurality of insertion spaces and an insert member formed by inserting an FRP molded body into the insertion spaces.

Therefore, the purpose of the present invention is to provide an injection molded product whose strength is improved by a strength reinforcement structure through an FRP molded body and the thickness of the metal frame constituting the insert member can be thinner, thereby achieving weight reduction and slimming, and a method for manufacturing the same. is to provide.

Another object of the present invention is to provide an injection molded product and a manufacturing method thereof that can increase production efficiency by minimizing bending of the metal frame constituting the insert member, which is performed as a way to increase the rigidity and strength of the final product. .

The object of the present invention is not limited to the object mentioned above, and even if not explicitly mentioned, the object of the invention that can be recognized by a person of ordinary skill in the art from the description of the detailed description of the invention described later may also naturally be included. .

In order to achieve the purpose of the present invention described above, the present invention first provides an insert consisting of a metal frame that is bent and processed several times to form a plurality of insertion spaces, and a plurality of FRP (Fiber Reinforced Plastic) molded bodies that are inserted into the plurality of insertion spaces. absence; and a resin layer formed to bury part or all of the insert member.

In a preferred embodiment, the metal frame has a thickness of less than 0.3T, and the insertion space and the FRP molded body have a fitting tolerance.

In a preferred embodiment, the FRP molded body includes a matrix made of a thermosetting resin or a thermoplastic resin; and one or more reinforcing fibers selected from the group consisting of glass fibers, aramid fibers, carbon fibers, metal fibers, ceramic fibers, natural fibers, and nanocarbon fibers located inside the matrix.

In a preferred embodiment, the reinforcing fibers are continuous fibers.

In a preferred embodiment, when the reinforcing fiber is a conductive fiber, the FRP molded body further includes a non-conductive coating layer formed on the surface.

In a preferred embodiment, the resin layer is formed of one or more of FRP and polymer resin.

In a preferred embodiment, the injection molded product is a smartphone front case.

In addition, the present invention includes the steps of bending and processing a metal plate several times to prepare a metal frame with a plurality of insertion spaces; Preparing a plurality of FRP (Fiber Reinforced Plastic) molded bodies having a size to fit into a plurality of insertion spaces formed in the metal frame; Preparing an insert member by inserting the FRP molded body into the insertion space of the metal frame; and placing the insert member in an injection mold and injecting resin to perform injection molding to form a resin layer that fills part or all of the insert member.

In a preferred embodiment, the step of preparing the FRP molded body is to mix glass fiber, aramid fiber, carbon fiber, metal fiber, ceramic fiber, natural fiber, and nanocarbon fiber in a matrix resin made of thermosetting resin or thermoplastic resin in a desired mold. and impregnating one or more reinforcing fibers selected from the group consisting of.

In a preferred embodiment, in the step of preparing the FRP molded body, continuous fibers are used as the reinforcing fibers.

In a preferred embodiment, when the reinforcing fiber is a conductive fiber, preparing the FRP molded body includes forming the FRP molded body and forming a non-conductive coating layer on the surface of the FRP molded body.

In a preferred embodiment, the injection molding step is performed so that a resin layer is formed that fills at least the surface of the FRP molded body exposed to the outside after being inserted into the insertion space of the metal frame.

According to the present invention described above, the strength is improved by the strength reinforcement structure through the FRP molded body, and the thickness of the metal frame constituting the insert member can be made thinner, thereby achieving weight reduction and slimming.

In addition, according to the present invention, bending of the metal frame constituting the insert member, which is performed as a way to increase the rigidity and strength of the final product, can be minimized, thereby increasing production efficiency.

These technical effects of the present invention are not limited to the scope mentioned above, and even if not explicitly mentioned, the effects of the invention that can be recognized by a person of ordinary skill in the art from the description of the specific contents for implementing the invention described later. Of course it is included.

Figure 1 illustrates an embodiment of a metal frame among insert members included in injection molded products according to various embodiments of the present invention.
Figure 2a shows an embodiment of the FRP molded body inserted into the insertion space of the metal frame shown in Figure 1, Figure 2b is a longitudinal and unidirectional cross-sectional view of the FRP molded body shown in Figure 2a, and Figure 2c is an FRP molded body This shows another implementation example.
Figure 3a shows an example of an insert member included in an injection molded product according to various embodiments of the present invention, and Figure 3b is a cross-sectional view taken along line AA.
Figure 4 shows one embodiment of an injection molded product according to various embodiments of the present invention.
Figure 5 is a flowchart showing a method of manufacturing an injection molded product according to various embodiments of the present invention.
Figure 6 is a conceptual diagram of a method for evaluating the amount of deformation under a design load for an injection molded product according to various embodiments of the present invention.

The terms used in the present invention are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the description of the invention, but are intended to indicate the presence of one or more other It should be understood that this does not exclude in advance the presence or addition of features, numbers, steps, operations, components, parts, or combinations thereof.

Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component without departing from the scope of the present invention.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless clearly defined in the present invention, should not be interpreted in an idealized or excessively formal sense. No.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description. In particular, when terms of degree such as "about", "substantially", etc. are used, they may be interpreted as being used at or close to that value when manufacturing and material tolerances inherent in the stated meaning are presented. .

In the case of a description of a temporal relationship, for example, if a temporal relationship is described as ‘after’, ‘after’, ‘after’, ‘before’, etc., ‘immediately’ or ‘directly’ Even non-consecutive cases are included unless ' is used.

Hereinafter, the technical configuration of the present invention will be described in detail with reference to the attached drawings and preferred embodiments.

However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Like reference numerals used to describe the invention throughout the specification represent like elements. Additionally, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

The technical feature of the present invention is that the strength is improved by the strength reinforcement structure through the FRP molded body, and the thickness of the metal frame constituting the insert member can be made thinner, thereby achieving weight reduction and slimming, and improving the rigidity and strength of the final product. Injection molded products and their manufacture using metal insert members with FRP moldings inserted into them, which can increase production efficiency by reducing assembly man-hours by minimizing the bending of the metal frame constituting the insert member, which is performed as a way to increase There is a method.

In other words, lightweighting is a very important issue as portable mobile devices, including smartphones, are trying to reduce the weight by even 1g, and in conventional injection molded products using metal frames as inserts, the resin layer is formed with glass fiber reinforced composite resin for strength. This is because, in order to improve strength, excessive glass fiber content of more than 50% is added to the glass fiber reinforced composite resin, resulting in a very high cost level.

Therefore, the injection molded product of the present invention includes a metal frame that is bent and processed several times to form a plurality of insertion spaces, and an insert member made of a plurality of FRP (Fiber Reinforced Plastic) molded bodies fitted into the plurality of insertion spaces; and a resin layer formed to bury part or all of the insert member.

In addition, the method for manufacturing an injection molded product of the present invention includes the steps of bending and processing a metal plate several times to prepare a metal frame with a plurality of insertion spaces; Preparing a plurality of FRP (Fiber Reinforced Plastic) molded bodies having a size to fit into a plurality of insertion spaces formed in the metal frame; Preparing an insert member by inserting the FRP molded body into the insertion space of the metal frame; and placing the insert member in an injection mold and injecting resin to perform injection molding to form a resin layer that buries part or all of the insert member.

Various embodiments of the present invention have been shown and described with respect to a portable electronic device for communication including a display module. However, it is not limited to this and can be applied to various electronic devices having a display module. Various embodiments of the present invention are directed to various electronic devices including a display on the front, such as a personal digital assistant (PDA), a laptop computer, a mobile phone, a smart phone, and a netbook. It can be applied to various electronic devices such as (Netbook), mobile Internet device (MID), ultra mobile PC (UMPC), tablet personal computer, navigation, MP3, and wearable electronic devices. You can.

Figure 1 illustrates an embodiment of the metal frame 110 among the insert members 100 included in the injection molded product 1 according to various embodiments of the present invention.

Looking at the metal frame 110 among the insert members 100 included in the injection molded product 1 of the present invention with reference to Figure 1, the metal frame 110 is not limited as long as it is made of metal, but as an example, SUS ( A metal plate 111 with a thickness of less than 0.3T made of one or more materials selected from the group consisting of Stainless Use Steel, aluminum, iron, and their alloys is bent and processed several times to form a plurality of insertion spaces 112. It can be formed. Accordingly, the metal frame 110 may include a metal plate 111 and a plurality of insertion spaces 112. Here, the number, size, and location of the insertion spaces 112 formed are designed to be optimal for reinforcing the overall strength of the metal frame 110 according to the purpose of the final product, and are fitted with the FRP molded body 120 to be fitted. There can be tolerances. That is, the insertion space 112 is designed to be slightly smaller than the FRP molded body 120 and can be bent. Additionally, processing may include punching the inside of the metal plate 111 and, if necessary, removing a portion of the exterior.

Figure 2a shows an embodiment of the FRP molded body inserted into the insertion space of the metal frame shown in Figure 1, Figure 2b is a longitudinal and unidirectional cross-sectional view of the FRP molded body shown in Figure 2a, and Figure 2c is an FRP molded body This shows another implementation example.

Looking at the FRP molded body 120 inserted into the insertion space 112 of the metal frame 110 constituting the insert member 100 with reference to FIGS. 2A to 2C, the FRP molded body 120 is a metal frame 110. In order to minimize the weight while reinforcing the overall strength of the matrix 121b made of thermosetting resin or thermoplastic resin, and glass fiber, aramid fiber, carbon fiber, metal fiber, ceramic fiber, natural fiber, and nano located inside the matrix 121b. It has a structure including one or more reinforcing fibers (121a) selected from the group consisting of carbon fibers, and is manufactured in a known manner by impregnating a plurality of reinforcing fibers (121a) with a resin that forms a matrix (121b) in a desired mold. It can be. The size and shape of the FRP molded body 120 may be a size and shape that fits into the insertion space 112 formed in the metal frame 110, that is, a size and shape that has a fitting tolerance with the insertion space 112.

Additionally, the FRP molded body 120 may be formed in a known manner, but considering strength and ease of use, the reinforcing fibers 121a may be implemented using continuous fibers as shown in FIG. 2B. As an example, if reinforcing fibers are used as continuous fibers to form an FRP molded body, pultrusion is used, or if it is manufactured as an integrated structure according to the structure to be inserted into the metal frame 110, filament winding and resin transfer molding are used. It can be manufactured in a variety of ways using prepreg compression molding, etc.

On the other hand, when the reinforcing fibers 121a included in the FRP molded body 120 are conductive fibers, as shown in FIG. 2C, the FRP molded body 120 is formed of the reinforcing fibers 121a and the matrix 121b. ) and may further include a non-conductive coating layer 122 formed to surround the surface of the FRP molded body 121. In other words, when an FRP molded body containing conductive fibers such as carbon fibers as reinforcing fibers is injected in direct contact with a metal frame, corrosion of the metal may be accelerated due to galvanic corrosion. The non-conductive coating layer 122 is not limited as long as it is an insulating material, but as an example, it may be a glass fiber-reinforced composite resin and/or a non-conductive polymer resin. At this time, to facilitate interfacial adhesion, the same type of resin as the thermoplastic resin and/or thermosetting resin forming the FRP molded body 121 may be used as the resin and/or non-conductive polymer resin forming the glass fiber reinforced composite resin.

Figure 3a shows an example of an insert member included in an injection molded product according to various embodiments of the present invention, and Figure 3b is a cross-sectional view taken along line A-A.

Referring to FIGS. 3A and 3B, it can be seen that the insert member 100 of the present invention is made of an FRP molded body 120 inserted into the insertion space 112 of the metal frame 110. In this way, since the insert member (!00) is composed of the metal frame 110 and the FRP molded body 120, even if the thickness of the metal frame 110 becomes thinner, sufficient strength can be secured through the reinforcement structure through the FRP molded body 120. You can. If necessary, the FRP molded body 120 does not need to be inserted into all the insertion spaces 112 formed in the metal frame 110 constituting the insert member 100.

Figure 4 shows one embodiment of an injection molded product according to various embodiments of the present invention.

Referring to Figure 4, it can be seen that the injection molded product 1 of the present invention includes an insert member 100 and a resin layer 200.

The resin layer 200 may be formed to bury a portion of the insert member 100 as shown, but, if necessary, it can also be formed to bury the entire insert member 100. The material forming the resin layer 200 is not limited as long as it is a resin generally used during injection molding, and may be formed of one or more of FRP and polymer resin. In the injection molded product 1 of the present invention, the resin layer 200 embedding the insert member 100 covers at least the surface of the FRP molded body 120 exposed to the outside after being inserted into the insertion space 112 of the metal frame 110. It can be formed to be buried to complete the strength reinforcement structure.

The injection molded product 1 of the present invention may be any injection molded product that uses a metal frame formed by bending and processing several times to reinforce strength as an insert member. As an example, it may be a smartphone front case.

Figure 5 is a flowchart showing a method of manufacturing an injection molded product according to various embodiments of the present invention.

Looking at the manufacturing method of the injection molded product of the present invention with reference to Figure 5, preparing a metal frame with a plurality of insertion spaces (S110), preparing an FRP molded body (S120), preparing an insert member (S130) ) and injection molding (S140).

The step of preparing a metal frame (S110) includes selecting a metal plate of a material and thickness that can be as light as possible considering the strength reinforcement structure using the FRP molded body; Bending several times to form the required number of insertion spaces; and removing unnecessary parts through punching.

The step of preparing the FRP molded body (S120) must be performed so that the FRP molded body has at least a size and shape that has a fitting tolerance with the insertion space formed in the metal frame. That is, in one embodiment, the FRP molded body is prepared to include thermosetting resin or thermoplastic resin and one or more reinforcing fibers selected from the group consisting of glass fiber, aramid fiber, carbon fiber, metal fiber, ceramic fiber, natural fiber, and nanocarbon fiber. The reinforcing fiber may be a continuous fiber, and when the reinforcing fiber is a conductive fiber, the step of preparing the FRP molded body includes forming the FRP molded body and forming a non-conductive coating layer on the surface of the FRP molded body; may include.

The step of preparing an insert member (S130) can be performed by inserting an FRP molded body prepared to have a fitting tolerance with each insertion space into the metal frame 110 in which a plurality of insertion spaces are formed.

The injection molding step (S140) is performed by placing the prepared insert member 100 in an injection mold and then injecting resin. At least, a resin layer that fills the surface of the FRP molded body exposed to the outside after being inserted into the insertion space of the metal frame. This is carried out so that (200) is formed. At this time, the resin layer may be formed of one or more of FRP and polymer resin.

Example 1

A metal frame having the structure shown in FIG. 1 was manufactured by bending and processing a SUS metal plate with a thickness of 0.2T and a width of 70 × 160 mm. The sizes of insertion spaces 1 to 3 formed in the metal frame are 80mm Molded bodies 1 to 3 were manufactured. FRP molded bodies 1 to 3 used continuous carbon fiber as the reinforcing fiber, epoxy resin as the matrix resin, and the non-conductive coating layer was formed to a thickness of 0.3 mm using glass fiber reinforced resin. After preparing the insert member by inserting FRP molded bodies 1 to 3 into the manufactured metal frame, it was placed in an injection mold, and glass fiber reinforced resin or general polymer resin was injected as the resin to manufacture injection molded product 1 having the shape of FIG. 4.

Example 2

Injection molded product 2 was manufactured in the same manner as in Example 1, except that the thickness of the metal plate in Example 1 was set to 0.1T.

Comparative example

In the example, the thickness of the metal plate was set to 0.3T, the number of bending of the metal plate was increased by 10 times compared to Example 1, and FRP molding agents 1 to 3 were manufactured and were not inserted into the metal frame, except that the material was the same as Example 1. The comparative example injection molded product was manufactured by carrying out the method.

Experiment example

After measuring the weight of the injection molded products 1 and 2 obtained in the Examples and the comparative injection molded products obtained in the Comparative Example, the amount of deformation at the design load, heat aging resistance, and impact resistance were tested as follows, and the results are shown in Table 1. showed.

The amount of deformation under the design load was completely fixed with a clamp on one side of the product (approximately 25 mm), and then a weight of a certain load was attached to the center of the opposite side, and the amount of deflection was observed according to the conceptual diagram of the deformation amount evaluation method under the design load shown in Figure 6. .

Heat aging resistance of injection molded products is determined according to industry standards by keeping the parts in a constant temperature bath at 60ㅁ2℃ It was confirmed that there were no deformations that would impede the original performance, such as changes, stickiness, or looseness between the insert and the injection resin. In the case of impact resistance, the test product was checked by freely falling from a height of 1 m onto a parallel steel plate (thickness of 10 mm or more). This test was performed once for each side so that each side of the falling test product touches the steel plate to prevent any effects on the appearance such as breaks, cracks, or deformation. It was confirmed that there were no defects affecting the .

Injection molded product 1 Injection molded product 2 Comparative example
injection molded product Weight (g) 38 29 47 Deformation at design load (mm) 2 3 2 Heat aging resistance No deformation No deformation No deformation impact resistance No modifications No deformation No deformation

As shown in Table 1, the injection molded product of the present invention is not only lighter as the thickness of the metal frame constituting the insert member is reduced by more than 20% compared to the comparative injection product, but the deformation amount, heat aging resistance, and impact resistance are equal or greater. It can be seen that it exhibits excellent characteristics.

Although the present invention has been illustrated and described with preferred embodiments as discussed above, it is not limited to the above-described embodiments and is intended to be used by those skilled in the art without departing from the spirit of the invention. Various changes and modifications will be possible.

1: Injection molded product 100: Insert member
110: metal frame 111: metal plate
112: insertion space
120: FRP molded body 121: Non-conductive coating layer
200: Resin layer

Claims (12)

An insert member made of a metal frame that is bent and processed several times to form a plurality of insertion spaces, and a plurality of FRP (Fiber Reinforced Plastic) molded bodies fitted into the plurality of insertion spaces; and
An injection molded product comprising a resin layer formed to bury part or all of the insert member, According to claim 1,
An injection molded product, wherein the metal frame has a thickness of less than 0.3T, and the insertion space and the FRP molded body have a fitting tolerance.
According to claim 1,
The FRP molded body includes a matrix made of thermosetting resin or thermoplastic resin; and one or more reinforcing fibers selected from the group consisting of glass fibers, aramid fibers, carbon fibers, metal fibers, ceramic fibers, natural fibers, and nanocarbon fibers located inside the matrix.
According to claim 3,
An injection molded product, wherein the reinforcing fibers are continuous fibers.
According to claim 3,
When the reinforcing fiber is a conductive fiber, the FRP molded body further includes a non-conductive coating layer formed on the surface.
According to claim 1,
An injection molded product, characterized in that the resin layer is formed of one or more of FRP and polymer resin.
The method according to any one of claims 1 to 6,
The injection molded product is an injection molded product, characterized in that it is a smartphone front case.
Preparing a metal frame with a plurality of insertion spaces by bending and processing a metal plate several times;
Preparing a plurality of FRP (Fiber Reinforced Plastic) molded bodies having a size to fit into a plurality of insertion spaces formed in the metal frame;
Preparing an insert member by inserting the FRP molded body into the insertion space of the metal frame; and
A method of manufacturing an injection molded product comprising: placing the insert member in an injection mold and injecting resin to form a resin layer that fills part or all of the insert member.
According to claim 8,
The step of preparing the FRP molded body is to add one selected from the group consisting of glass fiber, aramid fiber, carbon fiber, metal fiber, ceramic fiber, natural fiber, and nanocarbon fiber to a matrix resin made of thermosetting resin or thermoplastic resin in a desired mold. A method for manufacturing an injection molded product, comprising the step of impregnating the above reinforcing fibers.
According to clause 9,
In the step of preparing the FRP molded body, the reinforcing fiber is a method of manufacturing an injection molded product, characterized in that continuous fiber is used.
According to clause 9,
When the reinforcing fiber is a conductive fiber, the step of preparing the FRP molded body includes forming the FRP molded body and forming a non-conductive coating layer on the surface of the FRP molded body. .
According to claim 8,
The injection molding step is performed so that a resin layer is formed that fills the surface of the FRP molded body exposed to the outside after being inserted into the insertion space of the metal frame.