JP2007245205A - Hemming process of aluminum alloy panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hemming process capable of excellently hemming even a 6000-series aluminum alloy panel subjected to the room-temperature aging hardening. <P>SOLUTION: In the hemming process of an aluminum alloy panel, when a panel folded portion by a down-flange step, and a pre-hemming step subsequent thereto is further folded inward of the panel by a flat-hemming step or a roped-hemming step, the panel folded portion 1b is constrained by an elastic body 7 thicker than the thickness t of a final panel folded portion after the hemming inward of the panel from the direction of the panel peripheral edge; the elastic body 7 is pressed by a punch 4 together with the panel folded portion 1b to deform the elastic body 7 inward of the panel from the direction of the panel peripheral edge; and the panel folded portion 1b is pressed also by the deformation of the elastic body 7 together with the punch 4 to fold the panel folded portion 1b inward of the panel to the angle of nearly 180°. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aluminum alloy panel hem processing method (heme is also referred to as hemming) that is particularly suitable for use in automobile body panels (hereinafter, aluminum is also referred to as Al). The panel as used in the field of this invention means the panel by which hemming processed the shaping | molding processes, such as press, a cutting | disconnection, and bending, for the rolled aluminum alloy thin plate.

  Conventionally, panels such as outer panels (outer plates) and inner panels (inner plates) of panel structures such as automobile hoods, fenders, doors, roofs, and trunk lids have been made of thin and high-strength Al alloy panels. Al-Mg-based AA or JIS standard (satisfying the standards) of 5,000-based aluminum alloys with excellent formability and Al-Mg-Si-based 6000-based aluminum alloy sheets with excellent formability and bake hardenability (Rolled sheet material) has begun to be used.

  This 6000 series aluminum alloy sheet has excellent age-hardening ability, so it ensures formability by reducing the yield strength during press forming and bending, and at the time of artificial age-hardening treatment such as baking coating after forming. There is an advantage that the strength can be improved by age-hardening by heating and the required strength can be ensured. This characteristic is particularly excellent in the excess Si type 6000 series aluminum alloy. This excess Si type 6000 series aluminum alloy is basically an Al—Mg—Si series aluminum alloy containing Si and Mg as essential elements and having a Si / Mg weight ratio of 1 or more.

  In the outer panel of the automobile panel structure described above, after press molding, the outer panel is folded (turned 180 degrees) and joined to the edge of the inner panel after molding, hemming (helix folding) This is called hem processing.

  An outline of this hem processing is shown in FIGS. 3 (a) to 3 (d). As can be seen from FIG. 3, the outer panel obtained through the down flange process of FIG. 3 (a) after the press molding process and the outer periphery trim process is described in detail below, and the pre-hem process of FIG. 3 (b) is performed. After that, the process is basically performed by selecting the flat hem process in FIG. 3 (c) or the rope hem process in FIG. 3 (d).

  First, in the down flange process of FIG. 3 (a), the edge 1a of the outer panel 1 after the forming process, which is fixed by the die 3a and the plate holder 5a, is bent to an angle close to a right angle (90 °) by the punch 4a.

  Next, in the pre-hem process in FIG. 3 (b), the edge of the inner panel 2 after the forming process such as the drawing process or the trim process is accommodated (inserted) in the bent portion of the outer panel 1 after the down flange process, and then the outer panel 1 The inner panel 2 and the inner panel 2 are fixed by the die 3b and the plate holder 5b, and the edge 1b of the outer panel 1 is further bent inward to about 135 ° by the die 3b and the punch 4b. Reference numeral 6b denotes an end portion (peripheral portion, bent portion) of the bent portion of the outer panel 1.

  Further, in the flat hem process of FIG. 3 (c) and the rope hem process of FIG. 3 (d), the outer panel 1 and the inner panel 2 are fixed by a plate presser (not shown) and dies 3c and 3d, and the outer panel 1 The edges 1c and 1d are bent further inside by a punch 4c and 4d to an angle of 180 ° to form a flat hem or rope hem bent portion. In this way, the edge of the inner panel 2 and the edges 1c and 1d of the outer panel 1 which are the edges of the flat hem or rope hem (180-degree bent part) are in contact with each other, and both are joined at the ends. Close contact. Reference numerals 6c and 6d denote end portions (peripheral portions and bent portions) in the bent portion of the outer panel 1.

  Among these, the rope hem process in FIG. 3 (d) has a rope-like shape in which the shape of the hem edge bent portion (folded portion) swells in an arc shape compared to the flat hem process in FIG. 3 (c). It does not have a sharp or flat hem shape, and the appearance is not good. In addition, there is a problem that the contact area between the outer panel and the inner panel is small and the bonding property and adhesion are lacking.

  For this reason, in particular, in automotive parts and the like that place importance on the appearance and aesthetics, the final process of hem processing is usually performed by the flat hem process of FIG. 3 (c), which is a severe bending process.

  In recent years, outer panels such as hoods and doors have been made thicker to improve pedestrian protection performance, and inner panels have been made thinner. For this reason, the thickening of the outer panel to be hemmed reduces the flat hemming workability, and the thinning of the inner panel inserted into the edge bend of the outer panel also becomes strict as bending conditions, and the flat hemming workability is further improved. Reduce.

  On the other hand, the character line and shape of the outer panel of the automobile panel structure tend to be complicated, and the strength of the Al alloy panel is also increased to cope with the thinning. Reduces flat hem workability of alloy panels.

  For this reason, in response to changes in the environment and processing conditions that deteriorate the flat hem workability, the edge curve portion of the flat hem formed by flat hem processing of the Al alloy panel is also disclosed in Patent Documents 2 and 3 described later. Defects such as rough skin, minute cracks, and relatively large cracks (described in order of degree) that are disclosed in detail are likely to occur, and there is a high possibility that they cannot be applied to the panel structure.

  On the other hand, various technologies have been proposed to prevent the occurrence of defects such as wrinkles and cracks in the hem part (edge bent part, bent part) on the flat hem processing process side or on the material side of the Al alloy plate. Yes.

  For example, in flat hem processing of a high-strength aluminum alloy plate, the arc radius Rd (the shoulder radius of the die) of the flange bending portion formed in the outer panel material is increased in the down flange process of FIG. Specifically, in relation to the thickness of the aluminum alloy plate, it has been proposed that the bending radius Rd is 0.8 t to 1.8 t (where t is the thickness of the aluminum alloy plate) to prevent the occurrence of the defect. (See Patent Document 1).

  Also, a flat hem processing method for an aluminum alloy outer panel material, wherein the outer panel material is a Si-rich Al-Mg-Si aluminum alloy plate with a specific composition, and the characteristics of this plate are artificial under certain conditions. It has also been proposed to improve the hem workability of an aluminum alloy panel by specifying the yield strength after aging treatment (see Patent Document 2).

  Further, it is a hem processing method of an arc-shaped peripheral edge portion having an arc radius of 1500 or less in an aluminum alloy panel, wherein the arc-shaped peripheral edge portion is bent by approximately 180 ° to have a hem peripheral edge shape corresponding to the panel peripheral edge shape. There has also been proposed a hem processing method for an aluminum alloy panel in which a flange is bent to a length of 7 mm or less when forming the flange (see Patent Document 3).

Japanese Patent Publication No.63-2690 (full text) JP 2003-39124 A (full text) JP 2004-98154 A (full text)

  However, these conventional technologies only improve the material side of the plate, such as the definition of the hem bending radius and the flange bending length in relation to the thickness of the aluminum alloy plate, or the characteristics of the Al alloy plate. After all, there is a limit to improving the hemmability of the high-strength aluminum alloy panel under the severe environment described above. For this reason, it is necessary to improve the flat hem processing step.

  In particular, the 6000 series Al alloy, due to its excellent age-hardening ability, tends to cause age-hardening at room temperature (room temperature) after the production of the Al alloy material itself and before it is used for each of the above applications. Such a 6000 series Al alloy panel material aged at room temperature tends to have a buckled shape in which the bending tip is bent acutely at the time of hem processing, and there is a problem that the hem workability is remarkably lowered.

  For this reason, in particular, there has been no effective and practical forming method as a hem processing method for 6000 series aluminum alloy panels that have been age-hardened at room temperature. The actual situation is that measures such as reducing the molding process conditions at the expense of efficiency have been adopted.

  The present invention has been made by paying attention to such circumstances, and its purpose is to provide a processing method that can satisfactorily hem even an aluminum alloy panel such as 6000 series that has been age-hardened at room temperature. It is what.

  In order to achieve this object, the gist of the aluminum alloy panel hem processing method according to the present invention is an aluminum alloy panel hem processing method, in which the peripheral edge of the panel is moved to the inside of the panel by a down flange process and a subsequent prehem process. When the panel bent portion is further bent toward the inside of the panel by a flat hem process or a roped hem process, the panel bent portion is more than the thickness of the final panel bent portion after hem processing. By restraining the elastic body from the peripheral edge direction of the panel toward the inside of the panel by a thick elastic body, and pressing the elastic body together with the panel bent portion by the punch, the elastic body is deformed from the peripheral edge direction of the panel toward the inside of the panel, Along with the punch, the panel bending part is also deformed by the deformation of this elastic body. Pressure and is to shape by bending toward the panel bent portion to the panel inward to an angle of approximately 180 °.

  In the present invention, the elastic body is preferably a hard rubber.

  In the present invention, the down-flange process and the subsequent pre-hem process in hem processing may be a conventional molding method, and improve the subsequent flat hem process or roped hem process.

  According to the present invention, when the panel is bent further toward the inside of the panel by the flat hem process or the roped hem process, the panel bent part is restrained by the elastic body, and the elastic body is pressed with the panel bent part by a punch. Mold.

  In the conventional flat hem process or roped hem process in which the panel bent portion is directly pressed by a punch, the load (pressure) due to the punch tends to concentrate on a part of the panel bent portion, particularly on the bending peripheral portion. As a result, it is difficult to uniformly deform the panel bent portion over a wide range, and particularly at the bending peripheral portion, the formability (crack limit) of the hem is lowered and cracking is likely to occur.

  On the other hand, according to the present invention, the load (pressure) by the punch is distributed by being applied to the elastic body. In addition, the load applied to the elastic body also deforms the elastic body from the peripheral edge direction of the panel toward the inside of the panel (panel center side), and the deformation of the elastic body causes the panel bent portion to move laterally. Pressing toward the inside of the panel, the shape of the panel bent portion is made a shape close to a semicircle.

  By these combined effects, the panel bent portion is uniformly deformed over a wider range of the bent portion, and the formability (crack limit) of the hem is improved. As a result, even a 6000 series aluminum alloy panel that has been age-hardened at room temperature can be hemmed well.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings, particularly in the case of an outer panel such as a hood or a door for an automobile. An embodiment of the prehem process characteristic of the hem processing method of the present invention is shown in cross-sectional views in FIGS.

  In one embodiment of the hem processing method of the present invention, except for the flat hem process (or rope hem process) shown in FIGS. 1 and 2, the down flange process and the prehem process, which are the previous processes, are the same as those shown in FIGS. This is basically the same as that of the conventional hem processing in (b). That is, the process is basically performed by the flat hem process (or the rope hem process) shown in FIGS. 1 and 2 through the down flange process of FIG. 3 (a) and the prehem process of FIG. 3 (b).

  Although not shown in these drawings, a die 3 or a punch 4 having a curved or linear contact surface corresponding to the hem portion shape (outer periphery shape, character line) at the outer panel peripheral edge is used.

(Down flange process)
In the down-flange process of FIG. 3 (a), the aluminum alloy outer panel 1 after press forming such as drawing, overhanging, trimming, etc. is fixed by a die 3a and a plate presser 5a, and the peripheral edge of the outer panel 1 is fixed. The portion (tip portion) 1a is bent to an angle (approximately 90 °) close to 90 ° to 90 ° (right angle) by the punch 4a.

  At this time, it is preferable that the 90 ° bending radius of the corner portion 7a, which is the bending radius of the outer panel peripheral edge portion 1a, be in the range of 0.5 to 3.0. This 90 ° bending radius is performed by adjusting the shoulder radius Rd of the die 3a and the shoulder radius Rp of the punch 4a in FIG. 3 (a). When the 90 ° bend radius is less than 0.5, the accuracy of the shape and dimensions of the outer panel peripheral edge 1a (hem peripheral edge) when the hem processing conditions are particularly severe or flat hem processing is as follows. Although improved, there is a problem that defects such as cracks are likely to occur in the hem portion.

  On the other hand, when the 90 ° bend radius exceeds 3.0, the flatness of the hem part (hem edge curve part) like flat hem is lost and it becomes close to the rope hem shown in Fig. 3 (d), and the appearance of the hem part The aesthetic appearance is impaired. In addition, the contour line after the actual processing is shortened or too long compared to the originally designed outer diameter line or outline line of the edge of the flat hem. There is also a greater possibility of not.

(Prehem process)
Next, in the pre-hem process in FIG. 3 (b), the outer panel 1 after the down-flange process is fixed by the pre-hem die (lower mold) 3b and the plate holder 5b and bent by 90 °. 1a is further bent inward to about 135 ° by the punch 4b to form the outer panel peripheral edge 1b.

  At this time, an inner mold may be used, and the outer panel peripheral edge 1a may be brought into contact with the forming surface of the die, and the outer panel peripheral edge 1b contact surface may be formed into a shape bent inward to about 135 °. This makes it easier to obtain the shape accuracy when the outer panel peripheral edge 1a is bent and formed than when the mold 3b is not used.

(Flat hem process)
Thereafter, the outer panel peripheral edge portion 1b, which is a panel folding portion, formed by this prehem process is further bent toward the inside of the panel to an angle of about 180 ° by a flat hem process or a roped hem process. The selection of the rope hem process or the flat hem process is selected depending on the appearance and the necessity of the bonding property and adhesion between the outer panel and the inner panel.

(Use of elastic body)
In the present invention, an elastic body is used in this flat hem process or roped hem process, as shown in FIGS. 1 and 2, particularly for hem processing of room temperature aging materials and high strength materials.

  That is, as shown in FIG. 1, the outer panel peripheral edge 1b is restrained while being pressed by the elastic body 7. More specifically, the elastic body 7 sufficiently thicker than the thickness t (also referred to as the hem thickness) of the final panel bent portion 1c after the hem processing shown in FIG. Toward the left (from the right side to the left side of the panel in FIGS. 1 and 2), on the inner peripheral side surface 7a (7b in FIG. 2) of the elastic body, the bent portion 6a (6b in FIG. 2) of the panel peripheral edge 1b While pressing, restrains.

(Elastic body condition)
This elastic body 7 has such a characteristic that it can be elastically deformed without being plastically deformed when a load is applied from above (by the case of FIGS. 1 and 2) by a punch 4 (corresponding to the punch 4c in FIG. 3 (c)). It is selected from hard rubber or resin. When the elastic body 7 is plastically deformed by the load of the punch 4, the outer panel peripheral portion 1b, which is a panel bent portion, cannot be deformed.

  As the shape of the elastic body 7, an appropriate shape such as a rectangular shape, a circular shape, or an indeterminate shape is selected as long as the outer panel peripheral edge 1 a can be pressed uniformly. The contact surface shape of the punch 4 with the elastic body 7 may be a shape corresponding to the contact surface shape of the elastic body 7.

  However, the thickness of the elastic body 7 (length in the vertical direction in FIG. 1) is sufficiently thicker than the thickness t of the final panel bent portion (outer panel peripheral portion) 1c after hem processing in FIG. 2, as described above. is necessary. Therefore, FIG. 1 shows that the thickness of the elastic body 7 is sufficiently higher (larger) than the thickness t of the final panel bent portion after the hemming. This height (thickness) is set to a thickness sufficient to cause deformation, which is sufficient to deform the outer panel peripheral edge portion 1b, which is a panel bent portion. If the elastic body 7 is made thicker than necessary, the load on the punch 4 required for the deformation of the elastic body 7 becomes too large. A preferable thickness of the elastic body 7 depends on the hardness of the elastic body 7 but is approximately 1.2 to 1.5 t.

  If the thickness of the elastic body 7 is as thin as equal to or less than the thickness t of the final panel bent portion 1c, the load toward the elastic body 7 and the deformation of the elastic body 7 are reduced when the punch 4 is deformed by the load. For this reason, the pressing force of the outer panel peripheral edge 1b due to the deformation of the elastic body 7 is weakened or does not act, and the outer panel peripheral edge 1b cannot be deformed by the deformation of the elastic body 7. As a result, the load of the punch 4 is concentrated only on the outer panel peripheral edge 1b or on the outer panel peripheral edge 1b.

  This eliminates a significant difference from the conventional flat hem process or the roped hem process in which the panel bent portion is directly pressed by a punch, and the load (pressure) due to the punch tends to concentrate on a part of the panel bent portion, particularly on the bending peripheral portion. . Therefore, in particular, a room temperature aging material or a high strength material makes it difficult to uniformly deform the panel bent portion over a wide range, and particularly at the bending peripheral portion, the formability (crack limit) of the hem is lowered and cracking is likely to occur.

(Action of elastic body)
As shown in FIG. 2, by pressing the elastic body 7 with the punch 4, the elastic body 7 is deformed from the peripheral edge of the panel toward the inside of the panel (from the right to the left in FIG. 2). At this time, the deformation of the elastic body 7 is mainly the deformation toward the outer panel peripheral edge portion 1c which is a panel bending portion.

  The bent portion 6a of the outer panel peripheral edge portion 1b is pressed in FIG. 1 by both the deformed inner peripheral side surface 7b of the elastic body 7 and the punch 4 due to this deformation. Therefore, as shown in FIG. 2, the outer panel peripheral edge portion 1c (and the bent portion 6b) is bent toward the inside of the panel (left side in the figure) and finally bent inward to about 180 °.

  According to this aspect, when the outer panel peripheral edge 1b is further bent toward the inner side of the panel by the hem process, the panel bent portion is formed by both the lateral direction due to the deformation of the elastic body 7 and the upward direction by the punch 4. The outer panel peripheral edge 1b is pressed. That is, with the deformation of the elastic body 7 as an auxiliary driving force, the outer panel peripheral edge portion 1b, which is a panel bent portion, is bent toward the inside of the panel by the punch 4.

  As a result, unlike the conventional hem process in which the panel bent portion is directly pressed by the punch, the load (pressure) by the punch does not concentrate on a part of the panel bent portion, particularly on the bending peripheral portion. That is, according to the present invention, a part of the load by the punch 4 is converted into a pressing force from the lateral direction of the elastic body 7, so that the load directly applied to the outer panel peripheral portion 1b by the punch 4 is reduced. .

  Furthermore, by bending further while restraining the panel bent portion 1a by the pressing force of the elastic body 7 from the lateral direction, an acute buckling shape as shown in FIG. And a flat hem shape close to a semicircular shape can be obtained.

  As a result, the processing (deformation) of the outer panel peripheral edge portion 1b, which is a panel bent portion, is remarkably wide, uniform, and mild as compared with a direct load by a conventional punch. Therefore, the outer panel peripheral edge portion 1b is uniformly deformed over a wider range in the longitudinal direction, and the formability (crack limit) of the hem is improved. As a result, even a 6000 series aluminum alloy panel that has been age-hardened at room temperature can be hemmed well.

  In order to preferentially deform the elastic body 7 when pressed by the punch 4 toward the outer panel peripheral edge 1b, which is a panel bent portion, a jig is disposed on the outer peripheral side of the elastic body 7, and You may restrain the side.

(Aluminum alloy for panel)
As the aluminum alloy used in the present invention, 3000 series, 5000 series, 6000 series, 7000 series, etc., which are widely used for this kind of structural member use, depending on the use of the panel, or AA to JIS specified in AA to JIS. An aluminum alloy plate (rolled plate), which is a general-purpose alloy having a relatively high yield strength and tempered as necessary, is preferably used.

  However, a high-strength aluminum alloy plate having a 0.2% proof stress of 120 MPa or more is preferable for the panel used for the automobile. As an aluminum alloy that satisfies these characteristics, it usually has excellent age-hardening ability and a relatively small amount of alloy elements, and is excellent in scrap recyclability and formability. It is preferable to use an excess Si type 6000 series aluminum alloy. Excess Si type 6000 series aluminum alloy is most suitable in that it is easy to age at room temperature and is effective using the present invention.

  In the present invention, regarding the thickness of the aluminum alloy panel to be hemmed, in particular, the thickness of the aluminum alloy outer panel is 0.8 mm or more. This is preferable in that it is effective. The aluminum alloy inner panel having a thickness of 1.0 mm or less, which is less susceptible to hem processing, is preferable in view of the effect of the present invention.

  Next, examples of the present invention will be described. In order to support the effect of the elastic body used in the present invention, a flat hem processing test of 180 ° bending of an aluminum alloy plate was performed, in which flat hem processing was performed using the elastic body.

  As a 6000 series aluminum alloy for outer panels, a 1.0 mm thick test plate (0.2% proof stress 140 MPa in the rolling direction) aged for 6 months at room temperature with a T4 tempered material with AA6022 standard composition, T4 grade with AA6111 standard composition A test plate (0.2% proof stress 150 MPa in the rolling direction) with a thickness of 1.0 mm and aged at room temperature for 6 months was prepared.

  From these test plates, a bending test piece having a length of 150 mm and a width of 30 mm in the rolling direction was taken, and the flat hem workability was evaluated. That is, the test piece was simulated by pressing the outer panel of an automobile, 10% strain was added in advance, and the pre-strained part was bent about 90 ° in the longitudinal direction by a down flange process, Simulating the hem processing of an automobile outer panel, sandwiching an inner panel with a thickness of 0.8 mm, pre-hem processing, and flat hem processing at an angle of 180 ° were performed.

  The invention example is a test piece that has been subjected to the pre-hem processing and is bent by 180 ° using hard rubber (TRUSCO urethane rubber, rubber hardness of about 90 degrees) as the elastic body shown in FIGS. Flat hem processing was performed. The thickness of this hard rubber in the vertical direction is sufficiently higher than the hem thickness after hem processing of 2.8mm (equivalent to the thickness of the bent portion after hem processing: two 1.0mmt test pieces + inner plate thickness of 0.8mmt). 4.0 mm thickness and 5.0 mm thickness. As described above, the hard rubber had a rectangular cross-sectional shape having 4.0 mm thickness, 5.0 mm thickness (height) and 8.0 mm width, and had the same length as the width of the bending test specimen.

  For comparison, a hard rubber having a thickness of 2.5 mm thinner than a comparative example in which the conventional flat hem processing shown in FIG. Similarly, the heme processing test was also performed on the comparative example using. In both the inventive example and the comparative example, the 90 ° bending down-flange process was performed by the method of FIG. 4 (a), and the 135 ° bending pre-hem process was performed by the method of FIG. 4 (b).

The flat hem workability was evaluated by visual observation of the surface state of the test piece outside the final 180 ° bent portion (flat hem processed portion outer peripheral portion). The evaluation was carried out by visually checking the degree of occurrence of cracks on the outside of the bent part, and evaluated in five stages based on the following criteria.
0: No rough skin or fine cracks.
1: Rough skin has occurred.
2: Although there is rough skin, there is no cracking.
3: Small cracks occur.
4: Large cracks occur.
5: Fracture at the bent part.
Of the above ranks, 0 to 2 stages are acceptable as hem workability (for actual automobile outer panels), and 3 to 5 stages are unacceptable.

  As is apparent from Table 1, Invention Examples 1 to 4 are the comparative examples in which the flat hem processing using the elastic body shown in FIGS. 1 and 2 is performed and the conventional flat hem processing without using the elastic body is performed. Compared with 7 to 10, the flat hem processability is remarkably improved.

  Further, in the comparison between the AA6022 standard composition and the AA6111 standard composition, the AA6111 standard composition having a relatively high strength (yield strength) has a remarkable effect of improving the hemmability. Therefore, the effect and significance of the present invention for the hem processing of a 6000 series Al alloy plate (panel) that is aged at room temperature or has high strength (yield strength) are supported.

  As described above, according to the present invention, it is possible to provide a processing method that can satisfactorily heme even a 6000 series aluminum alloy panel that has been age hardened at room temperature. As a result, the present invention expands the application of high-strength aluminum alloys such as 6000 series aluminum alloys, which are easy to age harden at room temperature, particularly to automobile body panels.

It is sectional drawing which shows the one aspect | mode of the flat hem process in this invention hem processing method. It is sectional drawing which shows the aspect which the process of FIG. 1 advanced. A general hem processing method is shown, (a) is a down-flange processing panel, (b) is a pre-hem processing panel, and (c) is a cross-sectional view showing a flat hem processing panel.

Explanation of symbols

1: Outer panel, 2: Inner panel, 3: Die, 4: Punch, 5: Plate retainer,
6: bending part, 7: elastic body,

Claims (2)

  A method of hem processing of an aluminum alloy panel, in which a panel peripheral portion is bent toward the inside of the panel by a down flange process and a pre-hem process, and then the panel bent portion is further processed by a flat hem process or a roped hem process. When forming by bending toward the inner side of the panel, the panel bent portion is restrained from the peripheral edge of the panel toward the inner side of the panel by an elastic body thicker than the thickness of the final panel bent portion after the hem processing. The elastic body is deformed from the peripheral edge of the panel toward the inside of the panel by pressing with the panel bent portion, and the panel bent portion is pressed together with the punch by the deformation of the elastic body. Is bent to the inside of the panel to an angle of approximately 180 ° Hemming method of an aluminum alloy panel, characterized in that.   The method for hem processing an aluminum alloy panel according to claim 1, wherein the elastic body is hard rubber.

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