JP2014050863A - Metal formed body and method of producing metal formed body - Google Patents

Abstract

The present invention provides a metal molded body having sharp edge corners and a method for producing the same.
A metal molded body 2 having a corner portion 2c formed by molding a metal plate 1 mainly composed of light metal. The corner portion 2c of the metal molded body 2, than the thickness T of the flat portion 2p of the non-corner portion 2c present a thin region of thickness, the outer bending radius R _O of the corner portion 2c, the thickness of the flat portion 2p T or less. In order to produce the metal molded body 2, a bending groove 1g is first formed in a part of the metal plate 1 (step α). Next, the metal plate 1 is formed with the bending groove 1g inside the bending so that the outer bending radius R _O of the corner portion 2c is equal to or less than the thickness T of the flat portion 2p other than the corner portion 2c (step β). ).
[Selection] Figure 1

Description

  The present invention relates to a metal molded body having a corner formed by molding a metal plate mainly composed of light metal, and a method for manufacturing the metal molded body.

  Metal molded bodies of metal plates mainly composed of light metals such as Mg and Al are used in various industrial product components (for example, housings of electronic devices such as personal computers and mobile phones). In recent years, such component parts are often required to be designed, and specifically, it is desired to make the corners of the component parts sharp edges to provide an industrial product with a stylish design. That is, it is desired that the corners formed on the metal plate have sharp edges in the metal molded body that is the element of the component.

  For example, Patent Document 1 discloses a technique in which a corner is sharpened by pressing a metal plate in two stages. Specifically, in the first pressing step, the metal plate is bent so that the inner bending radius r of the corner is substantially 0 mm, and in the second pressing step, it is configured from the vicinity of the corner toward the corner. The materials are brought together so that the corner outer bending radius R is equal to or less than the thickness t of the metal plate. As a result, as shown in FIG. 4, it is possible to obtain a metal molded body 200 in which both the inner bending radius r and the outer bending radius R of the corner portion 200c are small.

JP 2010-69504 A

  Although the technique of the above-mentioned patent document 1 can produce a metal molded body having a corner portion having a very sharp edge, it is premised on performing two-step pressing, so there is room for improvement in terms of productivity. In particular, the demand for industrial products having sharp-edged corners has increased in recent years, and therefore it is desired to further improve the productivity of metal molded products having sharp-edged corners.

  The present invention has been made in view of the above circumstances, and one of the objects of the present invention is a metal molded body having sharp-edged corners and a metal molded body capable of producing the metal molded body with high productivity. It is in providing the manufacturing method of a body.

The metal molded body of the present invention is a metal molded body having a corner portion formed by molding a metal plate mainly composed of light metal, and the corner portion has a thickness T of a flat portion other than the corner portion. A region having a smaller thickness exists, and the outer bending radius R _O at the corner is equal to or less than the thickness T of the flat portion. Here, the “light metal” is a metal having a specific gravity of 5 or less, specifically, Mg, Al, Be, Ti, an alkali metal, an alkaline earth metal, or the like. The “metal plate mainly composed of light metal” is a metal plate containing “light metal” by 50% or more by mass%. Furthermore, “molding” includes all processing in which corners can be formed in a metal molded body. Typical “molding” includes pressing, drawing, bending and the like.

The metal molded body of the present invention has a stylish appearance because the corner has an outer bend radius R _O having a sharp-edged corner portion having a thickness T or less of the flat portion.

The method for producing a metal molded body according to the present invention is a method for producing a metal molded body in which corners are formed in a metal molded body by molding a metal plate mainly composed of light metals, and includes the following steps α and β. It is characterized by providing. The definitions of “light metal”, “metal plate mainly composed of light metal”, and “forming” are the same as those of the metal molded body of the present invention.
[Step α] ... A bending groove is formed on one side of the metal plate.
[Step β]... A metal plate is formed with the bending groove inside the bend so that the outer bend radius _RO of the corner is equal to or less than the thickness T of the flat portion other than the corner.

  FIG. 1 is an explanatory view simply showing a method for producing a metal molded body of the present invention, wherein (A) and (C) are states in which a groove for bending is formed in a metal plate before molding, (B) , (D) shows a state in which a metal formed body is produced by forming the metal plates (A) and (B) at the positions of the bending grooves, respectively. Examples of the method for forming the bending groove in step α of the production method of the present invention include cutting, pressing, polishing, and melting by laser. If cutting, pressing, and polishing are used, a portion thinner than the thickness T of the metal plate 1 is formed on one surface side of the metal plate 1 as shown in FIG. It becomes. On the other hand, if the melting by the laser is used, as shown in FIG. 1C, the portion hit by the laser is melted and dented to form a bending groove 1g. At that time, the melted constituent material of the metal plate 1 escapes to both sides of the bending groove 1g, so that both sides of the bending groove 1g are thickened so as to rise.

According to the method for producing a metal molded body of the present invention, as shown in FIGS. 1 (A) and (C), before forming the metal plate 1, by forming a bending groove 1g on the metal plate 1, The metal plate 1 can be easily formed at the position of the bending groove 1g. Further, when the metal plate 1 having the bending groove 1g is formed, the bending groove 1g is placed inside the bending, so that the outer side bending of the corner portion 2c is performed as shown in FIGS. The metal molded body 2 of the present invention in which the radius R _O is equal to or less than the thickness T of the planar portion 2p can be produced. The bending groove 1g formed on the metal plate 1 in the manufacturing method of the present invention leaves a trace on the metal molded body 2 of the present invention as a thin region at the corner 2c.

When a metal plate having a uniform thickness is bent, the constituent material of the metal plate approaches from the both sides of the corner toward the corner on the inner peripheral side of the corner, and the corner on the outer peripheral side of the corner is accordingly increased. The constituent material of the metal plate escapes from the corner toward both sides of the corner, and the outer bending radius R _O of the corner tends to increase. In particular, the outer bending radius R _O is not less than the thickness T of the flat portion other than the corner portion (that is, the thickness T of the prepared metal plate). For example, in order to set the outer bending radius R _O larger than the thickness T of the flat portion to be equal to or smaller than the thickness T of the flat portion, it is necessary to perform a second pressing step as in the technique of Patent Document 1, for example. .

  Hereinafter, the metal molded object of this invention and the preferable form of the manufacturing method are demonstrated.

  As one form of the metal molded body of the present invention, a form in which a polishing mark or a melt mark is formed on the inner peripheral surface of a thin region (thin region) at a corner portion can be exemplified.

  The surface state of the bending groove is a unique surface state corresponding to the method of forming the bending groove. Therefore, by observing the inner peripheral surface of the thin region that is a remnant of the bending groove, it is possible to know by which method the bending groove is formed. The reason for mentioning the polishing mark and the melting mark in the above configuration is that the formation of the bending groove by using polishing or melting by laser is advantageous in producing the metal molded body of the present invention. is there. The advantages will be described when the preferred embodiment of the production method of the present invention is described.

As one form of the metal molded body of the present invention, a form in which the outer side bending radius R _O of the corner part is 3/4 or less of the thickness T of the flat part can be mentioned.

A corner with an outer bend radius R _O less than the thickness T of the flat part gives a very stylish and sharp impression. Therefore, if an industrial product is produced using the metal molded body of the present invention, the industrial product can have a stylish and sharp impression. Therefore, the outer bending radius R _O is less than the thickness T of the plane portion, preferably 3/4 or less. To achieve an outer bend radius R _O as described above, the depth of the groove bend to be formed in the metal plate (distance to the deepest portion of the groove for bending the surface of the metal plate), the thickness of the metal plate It is good to set it to 1/3 or more and less than 1.

  As one form of the metal molded body of the present invention, the metal plate constituting the metal molded body can be an Mg alloy.

  Mg alloys (including pure Mg) are lightweight and have high hardness. Therefore, if an industrial product is produced using a metal molded body made of an Mg alloy, the industrial product can be reduced in weight, and the durability of the industrial product can be improved.

  As an embodiment of the metal molded body of the present invention made of an Mg alloy, the Mg alloy can include an embodiment that is an ASTM standard AZ91 equivalent material.

  Among Mg alloys, Mg—Al alloys in which Al is added as an additive element to Mg are excellent in corrosion resistance. In particular, the ASTM standard AZ91 equivalent material contains Al in an amount of 8.3 mass% to 9.5 mass% and Zn in an amount of 0.5 mass% to 1.5 mass%, and has very excellent corrosion resistance. Therefore, if an industrial product is produced using a metal molded body made of an AZ91-equivalent material, it is possible to improve the corrosion resistance of the industrial product in addition to reducing the weight and durability of the industrial product.

  The additive elements other than Al are selected from Zn, Mn, Si, Be, Ca, Sr, Y, Cu, Ag, Sn, Ni, Au, Li, Zr, Ce, and rare earth elements (excluding Y and Ce). And at least one element. When these additive elements are contained, the total content is preferably 0.01 to 10% by mass, and more preferably 0.1 to 5% by mass. Among these additive elements, a total of at least one element selected from Si, Sn, Y, Ce, Ca and rare earth elements (excluding Y and Ce) is 0.001% by mass or more, preferably in total. When the content is 0.1 to 5% by mass, heat resistance and flame retardancy are improved. Moreover, in the case of a rare earth element, it is preferable to contain 0.1 mass% or more, and among these, Y is preferably contained 0.5 mass% or more. Examples of the impurities include Fe.

  On the other hand, as an embodiment of the method for producing a metal molded body of the present invention, the bending groove can be formed by using polishing or melting by laser.

  As already described, various methods such as cutting, pressing, polishing, and melting by laser can be used to form the bending groove. Of these methods, polishing and laser melting are preferable because they are simple and can form a bending groove with almost no change in physical properties of the metal plate. In particular, when a laser is used, a bending groove can be formed in a very short time. When forming a bending groove using a laser, as shown in FIG. 1C, the molten constituent material rises on both sides of the bending groove 1g. That is, in the metal plate 1 having the bending groove 1g, the portion of the bending groove 1g is the thinnest and the both side portions of the bending groove 1g are the thickest. It becomes easier to bend the metal plate 1 along the bending groove 1g. As shown in FIG. 1 (D), the inner peripheral surface of the corner portion 2c of the metal molded body 2 obtained as a result is sandwiched between the recessed portion and the recessed portion toward the outside of the corner portion 2c, A unique shape is formed in which a raised portion is formed inside the metal molded body 2.

  Since the metal molded body of the present invention has corner portions that give a stylish and sharp impression, an industrial product using the metal molded body of the present invention can also have a stylish and sharp impression. Moreover, the manufacturing method of the metal forming body of this invention can manufacture the said metal forming body of this invention with sufficient productivity.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows simply the manufacturing method of the metal forming body of this invention, Comprising: (A) is the state which formed the groove | channel for bending in metal plate by grinding | polishing, cutting, etc., (B) is the metal plate of (A). A state where a metal molded body is formed by forming a metal plate at the position of the bending groove, (C) is a state where a bending groove is formed on the metal plate using a laser, and (D) is a bending of the metal plate of (C). The state which produced the metal molded object by shape | molding in the position of a groove for use is shown. It is explanatory drawing explaining the procedure of the manufacturing method of the metal forming body described in Embodiment 1, Comprising: (A) is the state which has arrange | positioned the metal plate in the metal mold | die, (B) is the state which pressed the metal plate. Show. (A) is explanatory drawing explaining the procedure of the additional process described in Embodiment 2, (B) is an enlarged view of the encircled part of (A). It is sectional drawing of the metal molded object obtained by the manufacturing method of the conventional metal molded object.

<Embodiment 1>
In Embodiment 1, a plurality of metal plates having different compositions are prepared, and a metal molded body is produced by the method for producing a metal molded body of the present invention in which bending grooves are formed in the metal plates, and the corners of the metal molded body are produced. The outer bend radius R _O was measured. For comparison, a metal molded body was produced by a conventional method for producing a metal molded body in which no bending groove was formed on the metal plate, and the outer bending radius R _O of the corner of the metal molded body was measured.

≪Preparation of metal plate≫
The prepared metal plates are the following three types. The plate thickness was a 0.8 mm rolled plate.
[Metal plate corresponding to AZ91] ... Mg alloy plate containing 8.3 mass% to 9.5 mass% of Al and 0.5 mass% to 1.5 mass% of Zn [Metal plate equivalent to AZ31] ... Al Mg alloy plate containing 2.5% to 3.5% by mass and 0.6% to 1.4% by mass of Zn [A5052-equivalent metal plate] ... 2.2% to 2.8% by mass of Mg %, Cr 0.15 mass% to 0.35 mass%, Si 0.25 mass% or less, Fe 0.4 mass% or less, Cu 0.10 mass% or less, Mn 0.10 mass% Hereinafter, an Al alloy plate containing 0.10% by mass or less of Zn

≪Formation of bending groove≫
A bending groove 1g as shown in FIG. 1A was formed by polishing the prepared various metal plates. Specifically, the bending groove 1 g includes a flat bottom surface portion that is substantially parallel to the flat surface portion of the metal plate 1 and a gentle curved surface portion that connects the bottom surface portion and the flat surface portion of the metal plate 1. The depth of the bending groove (the distance between the flat surface portion and the bottom surface portion of the bending groove 1g) was 0.2 mm or 0.4 mm. For comparison, a variety of metal plates in which no bending groove was formed were also prepared. That is, a total of nine types of metal plates having different compositions, presence / absence of bending grooves, and bending groove depths were prepared.

≪Press processing of metal plate≫
Nine kinds of prepared metal plates are pressed, and a flat top plate portion (planar portion) 20 as shown in FIG. 2B and a pair of flat side wall portions (from the top plate portion 20) ( The metal molded body 2 having a cross-section “[” shape having a flat surface portion 21 is manufactured. The metal press 2 was produced using the same press machine as in the past. The press working procedure is as shown in FIG.

  First, as shown in FIG. 2A, the metal plate 1 is placed on the plate 51 and the die plate 52 and sandwiched between the punch 53 and the pressing plate 54. In that case, about the metal plate 1 which has a bending groove | channel, the bending groove | channel is arrange | positioned facing the paper surface upper direction. This is because the upper side of the paper is the inside of the bending as will be described later.

  Next, as shown in FIG. 2 (B), the punch 53 is moved downward in the drawing with the metal plate 1 sandwiched between the plate 51 and the punch 53 so that the upper surface of the metal plate 1 is inside the bend. The metal plate 1 is formed into a metal molded body 2 having a cross-section “[” shape. Here, the bending radius Rp (see FIG. 2A) of the shoulder portion of the punch 53 is substantially 0 mm, and the two surfaces constituting the shoulder portion are orthogonal to each other. 21 is orthogonal. A corner portion 2 c is formed between the outer peripheral surface 20 o of the top plate portion 20 and the outer peripheral surface 21 o of the side wall portion 21, and a corner is formed between the inner peripheral surface 20 i of the top plate portion 20 and the inner peripheral surface 21 i of the side wall portion 21. Part is formed.

  The plate 51, the die plate 52, the punch 53, and the pressing plate 54 can be heated by a heating means (not shown). In the press working, the members 51 to 54 are heated, and the metal plate 1 is pressed in a state where the temperature of the metal plate 1 is the same as those of the members 51 to 54. The heating temperature at the time of pressing is preferably about 200 ° C. to 300 ° C. In this embodiment, the heating temperature at the time of pressing is about 250 ° C.

≪Result≫
About each metal molded object produced according to the said procedure, a metal molded object is cut | disconnected in the thickness direction of the top-plate part (plane part) 20 and the side wall part (plane part) 21, and the cross section is buff-polished (diamond abrasive grain # 200). And then observed with an optical microscope (400 times). Based on the observed image, the outer bending radius R _O of the corner of each metal molded body was measured. The measurement results are shown in Table 1.

As is apparent from the results in Table 1, by forming a bending groove in the metal plate before pressing, the outer bending radius R _O is flat in any of the metal plates corresponding to AZ91, AZ31, and A5052. Thus, a metal molded body having a corner portion with sharp edges was obtained. Further, by setting the depth of the bending groove to 3/4 to 1/2 of the plate thickness of the metal plate, the outer bending radius R _O could be set to 3/4 of the thickness T of the flat portion. On the other hand, when the bending groove is not formed in the metal plate before press working, any of the metal plates has an outer bending radius R _O larger than the thickness T of the flat portion and sharp corners. Only hard to say metal molded bodies were obtained.

<Embodiment 2>
The outer bend radius R _O at the corner of a metal molded body produced using a metal plate having a bending groove can be further sharpened. For example, additional processing corresponding to the second pressing step in Patent Document 1 is performed on the metal molded body obtained in the first embodiment. Hereinafter, the additional processing will be briefly described with reference to FIG. FIG. 3B is an enlarged view of the encircled portion of FIG. 3A after performing additional processing.

  In the additional processing, the end surface 21e of the side wall portion 21 of the metal molded body 2 is pressed using a convex stepped punch 55 as shown in FIG. The step punch 55 includes an end pressing surface 55p that presses the end surface 21e of the side wall portion 21, a shoulder 55s (see FIG. 3B) corresponding to the corner of the metal molded body 2, and the top plate 20 A main pressing surface 55m corresponding to the peripheral surface 20i.

  As shown in FIG. 3, the inner side of the metal molded body 2 is pressed by the step punch 55 in a state where the metal molded body 2 is disposed on a die 56 having a recess that fits into the outer shape of the box-shaped metal molded body 2. At this time, when the end pressing surface 55 p of the step punch 55 first presses the end surface 21 e of the side wall 21, the entire side wall 21 moves downward, and the lower constituent material of the side wall 21 moves to the corner of the recess of the die 56. As a result of being pushed together, an acute corner 2c is formed in the metal molded body 2 along the corner of the recess.

By performing the additional processing described above, the corner portion 2c of the metal molded body 2 can be made a sharper edge. Depending on the pushing amount, the outer bending radius R _O of the corner 2c can be substantially 0 mm.

  In addition, this invention is not necessarily limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably and can implement. For example, the bending groove formed on the metal plate in the first embodiment has a gentle shape having a flat bottom surface portion and a curved surface portion, but may be a V-shaped groove or an arc groove made only of a curved surface.

  The metal molded body of the present invention can be suitably used for constituent members of various industrial products, for example, a housing of a personal computer. Moreover, the manufacturing method of the metal molded object of this invention can be utilized suitably for manufacture of the metal molded object of this invention.

DESCRIPTION OF SYMBOLS 1 Metal plate 1g Bending groove 2 Metal molding 2c Corner | angular part 2p Plane part 20 Top plate part (Plain part) 20i Inner peripheral surface 20o Outer peripheral surface 21 Side wall part (Flat part) 21i Inner peripheral surface 21o Outer peripheral surface 21e End surface 51 Plate 52 Die plate 53 Punch 54 Holding plate 55 Step punch 55s Shoulder 55m Main pressing surface 55p End pressing surface 56 Die 200 Metal molded body 200c Corner

Claims (7)

A metal molded body having a corner portion formed by molding a metal plate mainly composed of light metal,
In the corner, there is a region having a thickness smaller than the thickness T of the flat portion other than the corner,
A metal molded body in which an outer bending radius R _O of the corner portion is equal to or less than a thickness T of the planar portion.   The metal molded body according to claim 1, wherein a polishing mark or a melting mark is formed on an inner peripheral surface of a thin region in the corner portion. The metal molded body according to claim 1 or 2, wherein an outer bending radius R _O of the corner portion is 3/4 or less of a thickness T of the planar portion.   The said metal plate is Mg alloy, The metal molded object as described in any one of Claims 1-3.   The metal molded body according to claim 4, wherein the Mg alloy is an ASTM standard AZ91 equivalent material. A metal molded body manufacturing method for forming a corner in a metal molded body by molding a metal plate mainly composed of light metal,
Forming a bending groove on one side of the metal plate; and
Forming the metal plate with the bending groove inside the bend so that the outer bend radius _RO of the corner is equal to or less than the thickness T of the flat portion other than the corner;
The manufacturing method of a metal molded object provided with.   The method for producing a metal molded body according to claim 6, wherein the bending groove is formed by polishing or melting by laser.

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