KR20170114888A - Method of manufacturing metal frame for middle frame of electronic device and metal frame for middle frame of electronic device - Google Patents

Abstract

An embodiment of the present invention provides a method of manufacturing a metal frame for an electronic device middle frame and a metal frame for an electronic device middle frame, in which the material cost is reduced, the manufacturing process is simplified, and the process defect rate can be reduced. Here, a method of manufacturing a metal frame for an electronic device middle frame includes the steps of extruding a metal material into a circular tube; Obtaining a circular ring-shaped metal material through a cutting process in which the circular tube is rotated relative to the cutter; Forming a circular ring-shaped metal material into a square ring shape; Applying a pressure to a rectangular ring-shaped metal material to obtain a intermediate member by deforming the cross-sectional shape so that the rectangular ring shape is maintained, and the cross-sectional shape thereof is deformed; And cutting the inner and outer sides of the intermediate member to obtain a metal frame.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a metal frame for a middle frame,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a metal frame for an electronic device middle frame and a metal frame for an electronic device middle frame. More particularly, the present invention relates to an electronic device A method of manufacturing a metal frame for a middle frame, and a metal frame for an electronic device middle frame.

In general, some of the handheld electronic devices, including Smartphones and Tablet PCs, have middle-frame applications. The middle frame may include a metal frame and a bracket. The metal frame forms a rim of the middle frame, forms a side portion of the portable electronic device to function as an outer case, and the bracket includes various electronic components And is used for the purpose of protecting or fixing. Recently, a metal frame is made of an aluminum alloy metal material to enhance durability. In addition, surface treatment using anodizing is performed for a luxurious appearance treatment.

Conventionally, a casting method is used as a method for manufacturing a metal frame. When a metal frame is manufactured by a casting method, materials such as silicon (Si), zinc (Zn), and manganese (Mn) are added to improve the fluidity of the aluminum alloy during casting. However, since such additive materials can act as impurities, there is a problem of lowering the strength of the formed metal frame. Further, among the additive materials, there is a problem of being discolored to black when anodized by silicon and zinc.

Therefore, in the case of the casting method, the anodizing process can not be performed and the painting process is performed. However, the coated middle frame can not have a more luxurious appearance than the anodizing process.

Further, in the case of production through casting, aluminum ingots are mainly used, and it is important that the fluidity of the alloy is ensured. However, the 6000 series and 7000 series of high strength aluminum have low fluidity and it is difficult to use because the strength is lowered when the additives are added to improve the fluidity. This phenomenon may occur even when the metal frame is manufactured by a die casting method.

Metal frames are also manufactured by drawing. In the drawing process, a metal plate is formed into a tub shape having a bottom or a wide cup shape by using a press or the like, and then a bottom portion is removed to produce a metal frame. That is, in the case of manufacturing through drawing, in order to manufacture a metal frame, the bottom portion of the drawn product must be processed and removed, so that the loss of material is large, and processing time and cost are also increased. In the case of drawing processing, a material having high strength and hardness such as 7000 series of aluminum has a problem that drawing processing itself is difficult.

Patent Registration No. 10-0684276 (Feb. 20, 2007)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a metal frame for an electronic device middle frame and a metal frame for an electronic device middle frame, which can reduce material costs, simplify a processing process, and reduce a process failure rate.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. There will be.

According to an aspect of the present invention, there is provided a method of manufacturing a metal frame for an electronic device middle frame, comprising the steps of: a) extruding a metal material into a circular tube; b) obtaining a circular ring-shaped metal material through a cutting process in which the circular tube is rotated relative to the cutter; c) forming the circular ring-shaped metal material into a square ring shape; d) applying a pressure to the rectangular ring-shaped metal material to obtain an intermediate material by deforming the cross-sectional shape so that the rectangular ring shape is maintained, and the cross-sectional shape thereof is deformed; And e) cutting the inner and outer sides of the intermediate member to obtain a metal frame.

In the embodiment of the present invention, the step (e) may include a step of surface-treating the intermediate member after cutting.

In an embodiment of the present invention, the surface treatment may comprise anodizing.

In the embodiment of the present invention, in the step e), at least one through hole may be further formed in the inner protrusion formed after the cutting of the intermediate member.

In the embodiment of the present invention, in the step (e), at least one of a slit, a hole and a notch may be further formed on a side surface of the body portion of the intermediate member.

In the embodiment of the present invention, in the step e), a hairline portion or a knurling portion may be further formed on the outer surface of the body portion of the intermediate member.

According to an aspect of the present invention, there is provided a method of manufacturing a metal tube, the method including: applying a pressure to a circular ring-shaped metal material obtained through a cutting process in which a circular tube formed by extruding a metal material is rotated relative to a cutter, A metal frame for an electronic device middle frame is provided by cutting the inside and outside of an intermediate member obtained by deforming the cross sectional shape so that the cross sectional shape is deformed.

In an embodiment of the present invention, an anodized treatment section may be provided on the surface of the metal frame.

In an embodiment of the present invention, the metal frame may have a body portion formed in a square ring shape and an inner projection formed on an inner peripheral surface of the body portion.

In an embodiment of the present invention, at least one of a slit, a hole, and a notch may be formed on a side surface of the body portion.

In an embodiment of the present invention, a hairline portion or a knurling portion may be further formed on an outer surface of the body portion.

In the embodiment of the present invention, the inner protrusion may further include at least one through hole.

According to the embodiment of the present invention, since the intermediate member can be integrally compressed and formed by the shape-deforming process, shape deformation such as warping can be prevented and the strength can be increased.

Further, according to the embodiment of the present invention, since the intermediate member is formed in a ring shape corresponding to the metal frame to be formed through the cutting operation, the loss of material due to the cutting process can be reduced and the machining time can be reduced.

Further, according to the embodiment of the present invention, it is possible to manufacture a metal frame that has undergone anodizing while minimizing material loss.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a flowchart illustrating a method of manufacturing a metal frame for an electronic device middle frame according to a first embodiment of the present invention.
FIG. 2 is a view illustrating a process of manufacturing a metal frame for an electronic device middle frame according to a first embodiment of the present invention. FIG.
3 is a cross-sectional view illustrating a part of a metal mold for manufacturing an intermediate material in a manufacturing process of a metal frame for an electronic device middle frame according to a first embodiment of the present invention.
4 is a plan view showing an intermediate member manufactured by a method for manufacturing a metal frame for an electronic device middle frame according to a first embodiment of the present invention.
5 is a sectional view taken along line AA in Fig.
6 is a sectional view taken along line BB of Fig.
FIG. 7 is a view illustrating an example of a manufacturing process after an intermediate member in a manufacturing process of a metal frame for an electronic device middle frame according to a first embodiment of the present invention.
8 is a cross-sectional view taken along line CC of Fig.
9 is a sectional view taken along line DD of Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" (connected, connected, coupled) with another part, it is not only the case where it is "directly connected" "Is included. Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a flowchart illustrating a method of manufacturing a metal frame for an electronic device middle frame according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of a metal frame for an electronic device middle frame according to a first embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a part of a mold for manufacturing an intermediate member in a process of manufacturing a metal frame for an electronic device middle frame according to a first embodiment of the present invention, and FIG. 4 is a cross- FIG. 5 is a cross-sectional view taken along the line AA of FIG. 4, and FIG. 6 is a cross-sectional view taken along the line BB of FIG. 4. As shown in FIG.

As shown in FIGS. 1 to 6, the method of manufacturing a metal frame for an electronic device middle frame according to the present embodiment may include a step S110 of extruding a metal material to form a circular tube. In step S110, the metal material may include a light metal such as aluminum, beryllium, magnesium, or titanium, or an alloy material including the light metal. In particular, the metal material may include duralumin. Duralumin means high-strength aluminum alloy which has an age hardening property by adding copper, magnesium and one or two kinds of elements to aluminum. As the aluminum alloy, 6000 series and 7000 series can be used. Specifically, the 6000 series of the aluminum alloy is an aluminum (Al) -magnesium (Mg) -silicon (Si) alloy, and the copper component is 1.2 or less in mass fraction%. Aluminum alloy 7000 series is an aluminum (Al) -Zn (Zn) -Magnesium (Mg) alloy and has a copper fraction of 2.6 or less in mass fraction percentage. Aluminum 6000 series alloy has good strength and corrosion resistance. 7000 series of aluminum alloy has very high strength. By using an aluminum-based alloy including duralumin as a metal material, the final product can secure a suitable strength.

In the step S110, the tube 200 may be formed as a hollow pipe having an inner hollow shape as shown in the figure, but it is not limited thereto, and may include pipes having various shapes such as a pipe having a rectangular ring shape can do.

After step S110, a step S120 of obtaining a circular ring-shaped metal material through a cutting process in which the circular tube is rotated relative to the cutter (not shown) may be performed.

In step S120, the tube 200 may be cut by the cutter and processed into a circular ring-shaped metal material 210. The cutter can cut the tube 200 by moving the cutting blade little by little from the outside of the tube 200 rotating in one direction to the inside of the tube 200. The tube 200 cut in the above-described manner can prevent the tube 200 from being deformed because the pressure exerted from the cutter is small. The method of machining the tube 200 into a circular ring shape is not limited to the example described above, and any method of machining the tube 200 into a circular ring shape may be used so that deformation does not occur in the tube 200.

In addition, the length of the circumference of the tube 200 may be similar to the length of the body portion 231 of the intermediate member 230. The cross-sectional area of the ring-shaped metal material 210 may be similar to or slightly larger than the cross-sectional area of the body portion 231 of the intermediate member 230. The ring-shaped metal material 210 may have a cross-sectional area that is smaller than the cross-sectional area of the first ring-shaped metal material 210 when the intermediate material 230 is subjected to subsequent forming and cross-sectional shape modification. The cross sectional area of the metal frame 240 formed by cutting the body portion 231 of the intermediate member 230 and the inner and outer projecting portions 232 and 233 may be further reduced than the cross sectional area of the intermediate member 230. Therefore, it is preferable that the cross-sectional area of the ring-shaped metal material 210 is formed so as to ensure a sufficient cross-sectional area when considering the entire process and the cross-sectional area of the metal frame 240.

After step S120, a step S130 of forming a circular ring-shaped metal material into a square ring shape may be performed.

In step S130, the forming may be performed by a pressing process using a punch (not shown). The punch is not limited to a specific configuration. For example, the punch may have an upper body and a lower body. The upper body may be formed in a shape in which a ring-shaped metal material 210 is formed. In this embodiment, the upper body may have a rectangular cross-section. The lower body may be formed to extend from a lower portion of the upper body, and may be formed in a horn or hemispherical shape to facilitate insertion into an inner through hole of a ring-shaped metal material 210. [ The punch may further include a stripper and a spring provided on both sides of the upper body or the lower body, and may further include an elevating module for moving the upper body and the lower body in the vertical direction. And, the punch can be driven by a small press capable of providing a pressing pressure of about 10 to 20 tons.

In the step S130, the pressing process for forming may be performed one or more times. For example, when the circumferential length of the ring-shaped metal material 210 is shorter than the length of the body portion 241 of the metal frame 240, the deformation and the length of the ring- This should all be done. Therefore, in such a case, one or more pressing processes can be performed so that stable forming can be performed by gradually deforming the shape. In this case, it is preferable that the thickness of the ring-shaped metal material 210 is formed thicker than the thickness considered in the above situation.

Alternatively, the ring-shaped metal material 210 may be formed into a square ring shape under the pressure applied in the up, down, left, and right directions by at least one rectangular block inserted therein for forming. Alternatively, the ring-shaped metal material 210 may be deformed by the tensile force applied to the hooks connected to four portions corresponding to the corners of the quadrangle and formed into a square ring shape.

In step S130, a step of annealing the ring-shaped metal material 210 before pressing may be further performed to improve the forming workability. The annealing may be performed at 440 to 460 ° C for 2 to 4 hours. The ring-shaped metal material 210 that has undergone the annealing treatment process has no internal residual stress and can be made finer by increasing the ductility, so that the foaming workability can be improved.

Meanwhile, the tube 200 processed by extruding the metal material may be in the form of a pipe having a rectangular ring shape. If the ring-shaped metal material has a rectangular ring shape and the total length of the ring-shaped metal material corresponds to or is similar to the length of the body portion 231 of the intermediate member 230, a small number of pressing processes can be performed And it is also possible to obtain a desired level of ring-shaped metal material 220 by a single pressing process, depending on the situation. Alternatively, the step of S130 may be omitted. In any case, since the ring-shaped metal material is formed in the ring shape connected to the entire length thereof, the square ring-shaped metal material 220 having undergone the forming process can also be formed in the entire length region.

After step S130, a rectangular ring shape is maintained by applying pressure to the square ring-shaped metal material, and step S140 may be performed to obtain an intermediate material by deforming the cross-sectional shape so as to deform the cross-sectional shape.

In step S140, the cross-sectional shape (see FIG. 5) of the square ring-shaped metal material 220 is deformed while the cross-sectional shape is deformed. Specifically, the intermediate member 230 in which the rectangular ring-shaped metal material 220 is formed through a sectional shape modification process includes a body portion 231 and an inner protrusion 232 (FIG. 23) extending inwardly and outwardly of the body portion 231, respectively And an outer projecting portion 233. The inner projecting portion 232 and the outer projecting portion 233 can be respectively formed from the body portion 231 by the pressure applied during the sectional shape deforming process. The outer protrusion 233 of the intermediate member 230 is to be removed through the cutting process in the process of forming the metal frame. However, by forming the outer protrusion 233 in the intermediate member 230 in step S140, It is possible to maintain the balance and uniformity of the internal structure of the inner tube 230. In addition, the outer projection 233 can be utilized as a reference for alignment with the jig to which the intermediate member 230 is to be seated during the subsequent cutting operation.

The mold 180 used for manufacturing an intermediate material in step S140 may have an upper mold 181 and a lower mold 182. [ The inner shapes of the upper mold 181 and the lower mold 182 may be formed to be symmetrical to each other. The upper mold 181 and the lower mold 182 are provided with a first forming portion 183 for pressing the metal material 220 to form the inner protrusion 232 of the intermediate material 230, (See FIG. 3 (a) and FIG. 3 (b)). The second forming portion 184 may be formed to have the outer protruding portion 233.

The metal material 220 flows into the first forming part 183 and the third forming part 185 during the pressing process of the upper mold 181 and the lower mold 182, The shape is deformed by squeezing. Since the metal material 220 is deformed while the material flows in both directions, the shape of the inner protrusion can be well formed, and the balance and uniformity of the inner structure can be obtained as a whole throughout the intermediate material 230.

In the absence of the third forming part 185, the metal material 220 is deformed while the material is flowing only in the first forming part 183, that is, only in one direction. However, the flowability of the material is poor, ) Or the inner protrusion 232 is formed, the balance and uniformity of the internal structure of the entire intermediate member 230 may not be good.

Further, the intermediate member 230 may further have the reinforcing portion 234. The reinforcing portion 234 may be formed at each corner inner portion. The reinforcing portion 234 may be formed on both side surfaces of the inner projecting portion 232. The fourth forming portion 186 may be further formed on the upper mold 181 and the lower mold 182 to form the reinforcing portion 234 (see (c) and (d) of FIG. 3). The reinforcing portion 234 can help each side of the intermediate member 230 to be formed perpendicular to each other. Since the sectional shape of the intermediate member 230 is different from the sectional shape of the portion where the reinforcing portion 234 is formed and the portion of the intermediate member 230 where the reinforcing portion 234 is not formed, the sectional shape of a part of the intermediate member 230 may be different.

In the cross-sectional shape modification process in step S140, a cross-sectional shape is deformed by applying pressure to the rectangular metal material 220, but the rectangular ring shape can be maintained at this time. In addition, the deformation of the cross-sectional shape through the above-mentioned cross-sectional shape deformation processing may be a deformation without being cut and crushed. The cross-sectional shape deformation processing may be forging processing. In addition, the cross-sectional shape modification process may have a plurality of stroke processes.

Also, in step S140, the rectangular ring-shaped metal material 220 may be cold-forged. The press used in the cold forging process may be a large press having a capacity of 400 tons or more. Specifically, in the case of the hot forging process, it takes time to apply heat to the square ring-shaped metal material 220, and a device capable of withstanding high temperatures is additionally required. However, since the cold forging can be performed immediately at room temperature, the process can be carried out quickly, and a separate apparatus for enduring high temperatures is not required, which is economical. When a press having a capacity of less than 400 tons is used in the cold forging process, the square ring-shaped metal material 220 may not be deformed as desired because of a lack of pressure. Therefore, it is preferable to use a large press having a capacity of 400 tons or more in the cold forging process so that the amount of forging can be secured for material deformation. As lightweight alloys used in the cold forging process, Aluminum 6000 series may be used.

On the other hand, when the rectangular ring-shaped metal material 220 is made of 7000-series aluminum material, the strength of the rectangular ring-shaped metal material 220 is very high. Therefore, the capacity of the press required for the cold forging process have. Therefore, when the square ring-shaped metal material 220 is made of aluminum material of 7000 series, the forging process in step S140 is not limited to the cold forging process but can be performed by the hot forging process. In the case of the hot forging process, the metal material 220 may undergo a preheating process at 300 to 400 ° C. According to the present invention, when 7000 series of aluminum is used, only 7000 series of aluminum can be manufactured by introducing only the hot forging process in the same process described above. The 7000 series of aluminum is difficult to draw, but it can be applied to the hot forging process.

In addition, in the above-mentioned cross-sectional shape-deforming step, the press can apply pressing to the rectangular metal material 220 a plurality of times. That is, the press can apply the pressing pressure a plurality of times so that the rectangular metal material 220 is deformed into the predetermined intermediate material 230.

As described above, the intermediate member 230 formed by the cross-sectional shape transformation is dense and has a high hardness and strength. In general, it is known that a product manufactured through forging is 3 to 5% more intense than a product manufactured through a drawing process. Such an increase in strength can be applied to a portable electronic device to provide an effect of increasing the durability of a metal frame frequently exposed to an external force such as a bending force.

In addition, since the intermediate member 230 according to the present invention can be integrally formed by forging, it can be prevented from deforming such as warping. Therefore, thereafter, when the intermediate member 230 is cut, it is possible to achieve the effect of ensuring the attachment to the cutting apparatus and preventing the breakage of the cutting tool. Further, since the intermediate member 230 is formed in a ring shape corresponding to a metal frame (not shown) to be formed through the subsequent machining, material loss due to finish machining can be reduced and machining time can be reduced.

The body part 231 of the intermediate member 230 obtained through step S140 may be formed in a rectangular ring shape and the inner and outer projecting parts 232 and 233 may be provided on the inner and outer circumferential surfaces of the body part 231, . The body portion 231, the inner projecting portion 232, and the outer projecting portion 233 may be connected to each other over the entire length.

7 is an exemplary view showing a manufacturing process after an intermediate member in a process of manufacturing a metal frame for an electronic device middle frame according to the first embodiment of the present invention, FIG. 8 is a sectional view taken along the line CC in FIG. 7, Fig. Hereinafter, the present invention will be described with reference to FIGS. 7 to 9. FIG.

After step S140, a metal frame may be obtained by cutting the inner and outer sides of the intermediate member (S150). In step S150, the inner protrusion 232 of the intermediate member 230 may be machined to form one or more through holes. The machining in step S150 may be a computer numerical control (CNC) machining, specifically, machining by computer numerical control.

In step S150, one or more reference holes (not shown) are passed through the inner protrusion 232 and the outer protrusion 233 of the intermediate member 230 to position the intermediate member 230 in the correct position in the machine tool for cutting. . A pin (not shown) provided on the machine tool may be coupled to the reference hole, so that the intermediate member 230 can be accurately positioned on the machine tool.

The inner protruding portion 242 may have a function of a support for preventing the deformation of the body 241 as well as a function of a support for supporting the bracket 250 in close contact. In cutting the inner protrusion 232, the pin of the machine tool may be coupled to the reference hole formed in the outer protrusion 233. Further, at the time of cutting the outer projecting portion 233, the pin may be in a state of being coupled to the reference hole formed in the inner projecting portion 232.

Then, the outer projecting portion 233 can be cut and removed. The inner protrusion 242 may further include at least one through hole 243. The through hole 243 may be formed by machining a reference hole formed in the inner protrusion 232, or may be formed at a different position.

A step of cutting the body part 231 of the intermediate member 230 to obtain the body part 241 of the metal frame 240 may be further performed in step S150. In addition, in step S150, the corner portion of the body portion 231 may be faced or rounded through computer numerical control processing. A hairline portion or a knurling portion may be further formed on the outer circumferential surface of the body portion 241. Further, in step S150, various processes may be further performed to form at least one of the hole 244, the slit 245, and the notch (not shown) in the body portion 241 through computer numerical control processing.

The order of cutting in step S150 is not limited to the above-described order. That is, after the body portion is first cut, the protruding portion may be cut. Also, the inner protrusion 232 may be cut before the outer protrusion 233, or the outer protrusion 233 may be cut before the inner protrusion 232, in the order of cutting of the protrusion.

In addition, the step S150 may include a step of surface-treating the intermediate member after cutting. Specifically, the metal frame 240 can be surface-treated by a sanding and anodizing process. The sanding may include sand blasting, which is a surface treatment method of polishing the surface of the workpiece by uniformly spraying the abrasive such as sand through the compressed air or the impeller to the workpiece at high speed and polishing the surface. Anodizing is a surface treatment method that protects a product with an oxide film formed by intentionally oxidizing and corroding a surface of a metal material and enables coloring on the porous surface.

In this embodiment, the surface of the metal frame 240 can be uniformed and polished by a sanding process in which an abrasive such as sand is jetted at high speed onto the surface of the metal frame 240. In this embodiment, by applying the sanding process to the metal frame 240, the deformed structure can be removed or uniformed during the cross-sectional shape deforming process. When the sanding process is completed, the anodizing process can be applied. The anodizing process may be a process of immersing the metal frame 240 in a solution and electrically oxidizing the metal frame 240 to form a porous transparent oxide layer on the surface of the metal frame 240, and then attaching various dyes on the porous transparent oxide layer.

The surface of the metal frame 240 may be provided with an anodized treatment unit 249 by the surface treatment. The processing unit 249 may be provided entirely on the surface of the metal frame 240. Through such surface treatment, it is possible to cause the metallic frame 240 to exhibit the original color of the metal.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

200: tube
210: ring-shaped metal material
220: square ring-shaped metal material
230: intermediate goods
231, 241:
232, 242:
233: outer protrusion
234:
240: metal frame
243: Through hole
244: hole
245: slit

Claims (12)

A method of manufacturing a metal frame for an electronic device middle frame,
a) extruding a metal material and processing it into a circular tube;
b) obtaining a circular ring-shaped metal material through a cutting process in which the circular tube is rotated relative to the cutter;
c) forming the circular ring-shaped metal material into a square ring shape;
d) applying a pressure to the rectangular ring-shaped metal material to obtain an intermediate material by deforming the cross-sectional shape so that the rectangular ring shape is maintained, and the cross-sectional shape thereof is deformed; And
and e) cutting the inner and outer sides of the intermediate member to obtain a metal frame. The method according to claim 1,
Wherein the step (e) includes a step of surface-treating the intermediate member after cutting. 3. The method of claim 2,
Wherein the surface treatment comprises anodizing. ≪ Desc / Clms Page number 20 > The method according to claim 1,
Wherein at least one through hole is further formed in the inner projecting portion formed after the cutting of the intermediate member in the step (e). The method according to claim 1,
Wherein at least one of a slit, a hole and a notch is further formed on a side surface of a body portion of the intermediate member in the step e). The method according to claim 1,
Wherein a hairline portion or a knurling portion is further formed on the outer surface of the body portion of the intermediate member in the step (e). A square ring shape is maintained by applying a pressure to a circular ring-shaped metal material obtained through a cutting process in which a circular tube formed by extruding a metal material is relatively rotated with respect to the cutter, and is obtained by deforming a cross- A metal frame for an electronic device middle frame, which is formed by cutting the inside and outside of the intermediate member. 8. The method of claim 7,
Wherein the surface of the metal frame is provided with an anodized treatment portion. 8. The method of claim 7,
Wherein the metal frame has a body portion formed in a square ring shape and an inner projection formed on an inner peripheral surface of the body portion. 10. The method of claim 9,
Wherein at least one of a slit, a hole and a notch is formed on a side surface of the body portion. 10. The method of claim 9,
And a hairline portion or a knurling portion is further formed on an outer surface of the body portion. 10. The method of claim 9,
Wherein at least one through hole is further formed in the inner projecting portion.

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