JP4658630B2 - Trimming method of aluminum alloy molded plate - Google Patents

Description

  The present invention relates to a method for trimming a 6000 series aluminum alloy molded plate after forming which generates less chips.

  Aluminum or aluminum alloy plates (hereinafter collectively referred to as aluminum alloy plates) used for automobile panels and parts thereof, electrical equipment panels, precision parts, etc. are formed by pressing these material plates, such as press molding. Alternatively, trimming is performed to remove an edge (excess portion) of a molded product (hereinafter also referred to as a panel) to obtain a product panel. In recent years, demands for weight reduction of automobiles have increased, and aluminum alloy sheets have been used as automobile panel materials instead of conventional steel sheets. Furthermore, among aluminum alloy plates, the use of AA to JIS 6000 series aluminum alloy plates, which have bake hardness that increases in strength after paint baking and can be expected to be lighter, is increasing. However, even when these aluminum alloy plates are used, the process from forming to trimming is basically the same as that for steel plates.

  That is, when a molded product is obtained from a material aluminum alloy plate by press forming, after forming the material, trimming is performed to remove the edge of the formed plate, and unnecessary portions (hereinafter referred to as “unnecessary portions”) are formed from the formed plate. An operation of removing a scrap portion) and leaving a shape portion of a molded product is performed. In this trimming process, generally, the shape part of the molded product is pressed against the lower blade and fixed by a member, and the molded plate is shear-cut (sheared) with the upper blade and the lower blade to remove the scrap part. ing.

  More specifically, a conventional representative trimming method will be described with reference to FIG. FIG. 6 is a schematic diagram showing a conventional typical trimming apparatus. In FIG. 6, the molded plate 7 after molding is sandwiched between the lower blade 10 and the pressing plate 8, and the portion to be removed is protruded from above the lower blade 10. It is supported by the plate 8. Thereafter, the upper blade 9 is lowered as indicated by an arrow 11, and an unnecessary portion (scrap portion) of the aluminum alloy molded plate 7 is shear-cut by shearing with the upper blade 9 and the lower blade 10. The upper blade 9 is then lifted, and the scrap portion is trimmed and removed by a press operation in which the upper blade 9 reciprocates once.

  The molded product after trimming is used as a panel or a part constituting an automobile or the like after undergoing a bending process, an assembly process, a painting process, and the like.

  However, the shear cutting may cause burr on the end face after the shearing process, which may be lost to generate chips (abrasion powder). The generated swarf adheres to the molded product shape part and the molding die of the workpiece, and forms irregularities called stars on the surface of the molded product. If there are irregularities on the surface of the molded product, color unevenness in which the painted surface does not become a uniform color, that is, unevenness in the coating, will occur in the subsequent painting process. For this reason, when a star is formed, the surface of the molded product is polished to remove irregularities. In this case, if there are many molded products that need to be reworked, this may cause a decrease in productivity. For this reason, various studies have been made so far that no abrasion powder is generated during trimming.

  As a method for this, a continuous groove portion is formed along the trim line and a cut line intersecting the trim line, and the scrap portion is pushed by a plurality of push bars, and the groove portion is separated as a leading end according to the trim line and the cut line. A method for performing trimming has been proposed (see Patent Document 1). In this method, after a groove is formed at a predetermined position of the molded product, trimming is performed using the groove as a separation tip, so that an unnecessary portion is reliably separated from the molded product shape portion through the groove. Thus, burr is prevented from occurring on the molded product shape portion side.

Japanese Patent No. 290889 (pages 1 to 3, FIG. 1)

  However, when trimming a molded product formed from an aluminum alloy plate, if the trimming is performed under the same conditions as a conventional steel plate, burr is likely to occur after trimming because the steel plate and the aluminum plate have different burr generation behavior. There is a problem. For this reason, in the case of an aluminum alloy plate, chips are more likely to be generated than a steel plate, and the occurrence rate of unevenness after coating increases.

  Furthermore, among the aluminum alloy plates that are press-formed and trimmed, the AA to JIS 6000 series aluminum alloy plates have more chips than the other 5000 series aluminum alloy plates due to the shear cutting during trimming. There is a unique tendency to occur easily.

  This is presumably due to the fact that the 6000 series aluminum alloy plate is more susceptible to cracks on the cut surface of the plate with a smaller amount of biting of the shear blade than other 5000 series aluminum alloy plates. When the cut surface of the plate is cracked with a smaller amount of biting by the shearing blade, the cut surface of the plate becomes a shape in which chips are easily produced.

  Fig. 7 shows the shear blades when the same 1mm thickness, 6000 series and 5000 series aluminum alloy plates and mild steel plates were trimmed under the same conditions as shown in Fig. 6 when the plates were cracked. Each bite (mm) is shown. As shown in FIG. 7, it can be seen that the 6000 series aluminum alloy plate is prone to cracking with less biting amount of the shearing blade.

  For this reason, there has been a demand for a trimming method that can suppress the generation of swarf that is effective for a 6000 series aluminum alloy plate that tends to generate such swarf.

  This invention is made | formed in view of this problem, Comprising: It aims at providing the trimming method of the 6000 series aluminum alloy molded board which can suppress generation | occurence | production of a chip easily and reliably.

  In order to achieve the above object, the gist of the aluminum alloy molded plate trimming method of the present invention is the method of trimming a 6000 series aluminum alloy molded plate after forming by shearing the upper blade and the lower blade. Each cutting edge R of the upper blade and the lower blade is in the range of 80 to 300 μm.

  As shown in FIG. 7, the 6000 series aluminum alloy plate has a shape in which the cut surface of the plate is easily cracked and the cut surface of the plate is easy to generate chips with a smaller bite amount of the shearing blade. This leads to easy generation of chips.

  Therefore, if the amount of biting of the shearing blade is increased until the 6000 series aluminum alloy plate cracks, the cutting surface of the plate is prevented from becoming a shape that tends to generate chips, and the generation of chips is suppressed. Can do.

  Therefore, in the present invention, the cutting edge R of each of the cutting edges at the time of trimming is set to a range of 80 to 300 μm for each cutting edge R of the upper blade and the lower blade. Make R relatively dull and increase the amount of biting of the shear blade until cracks occur in the cut surface of the 6000 series aluminum alloy sheet.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing the structure of a trimming mold of the trimming apparatus of this embodiment. FIGS. 2 and 3 show the state of shear cutting by the trimming die in FIG. 1, FIG. 2 is a schematic diagram showing the state of plate pressing in the initial stage of shear cutting, and FIG. 3 is the state after plate shearing.

  First, in FIG. 1, an aluminum alloy molded plate 1 after forming such as press forming is sandwiched between a lower die (lower blade) 4 and a pad which is a plate pressing member 2. The aluminum alloy molded plate 1b on the molded product side is positioned on the lower mold 4, and the aluminum alloy molded plate 1a on the scrap side is positioned to extend away from the upper mold 4. A dotted line 5 indicates a cut (assumed) plane of the aluminum alloy molded plate 1.

  In the embodiment of FIG. 1, the lower mold 4 is fixedly installed. Of course, the lower die 4 may not be fixed and may be configured to be moved up and down (moved) in cooperation with the upper die (upper blade) 3. In FIG. 1, the pad 2 is disposed above the lower mold 4 and in the vicinity of the upper mold (upper blade) 3. On the other hand, the upper die (upper blade) 3 is supported by the support frame (frame) 6 together with the pad 2 so as to be able to be moved up and down (moved) upward or downward.

  The lower die 4 and the upper die 3 have a constant clearance c between their blade surfaces (shear surfaces) 4b and 3b with respect to the cut (assumed) surface 5 of the 6000 series aluminum alloy molded plate 1. The blade surfaces are arranged so that they move (raise and lower) in parallel.

  As shown in FIGS. 2 and 3, the upper die 3 moves in a vertically downward direction so as to slide on the lower die 4 in cooperation with the pad 2, and between the upper die 3 and the lower die 4. The unnecessary portion (scrap portion) 1 a that protrudes from the lower mold 4 of the 6000 series aluminum alloy plate 1 is sheared and removed at the cut surface 5 by shearing.

(Shearing blade R)
Here, the characteristic configuration of the present invention includes a cutting edge R ₁ of the upper die 3, and a cutting edge R ₂ of the lower die 4, and each 80 to 300 [mu] m range. The cutting edge R ₁ and the cutting edge R ₂ are R ₁ at the cutting surface corner of each cutting edge or R 1 at the cutting surface corner, as shown in FIGS. Thus, the cutting edge R ₁ of the upper die 3, and a relatively blunt and cutting edges R ₂ of the lower die 4, 6000 the cut surface 5 of an aluminum alloy molded sheet 1 of shear blades to crack The amount of biting is increased, and the cutting surface 5 of the plate is prevented from becoming a shape in which chips are likely to be produced, and the generation of chips is suppressed.

If the cutting edges R ₁ and R ₂ are less than 80 μm, the cutting edge R is too small, the cutting edge R is too sharp, and the cutting of the 6000 series aluminum alloy molded plate 1 during trimming is the same as the conventional cutting edge R. The amount of biting by the shearing blade until the surface 5 is cracked does not increase. For this reason, generation | occurrence | production of swarf cannot be suppressed. Note that the cutting edges R ₁ and R ₂ immediately after normal sharpening are about 20 μm. On the other hand, when the cutting edges R ₁ and R ₂ exceed 300 μm, the cutting edge R is too large and the amount of biting of the shearing blade becomes too large, making trimming itself difficult.

A cutting edge R ₁ of the upper die 3, in order to cutting edge R ₂ and each 80 to 300 [mu] m in the range of the lower die 4, after dressing the cutting edge and the cutting edge of the lower die 4 of the upper die 3 Polishing with a sandpaper or other polishing tool, each cutting edge R is in the range of 80-300 μm.

(Shear cutting status)
The state of shear cutting of the 6000 series aluminum alloy molded plate 1 by the trimming die having such a configuration will be described below. In the initial stage of shear cutting in FIG. 2, when the upper die 3 is lowered together with the support frame 6 toward the lower die 4 in the direction of the arrow, the cooperating pad 2 also starts to descend.

  The bottom surface 2a of the pad 2 comes into contact with the upper surface of the 6000 series aluminum alloy formed plate 1 as the pad 2 descends. When the pad 2 further descends, the bottom surface 2a of the pad 2 presses the aluminum alloy molded plate 1 and plays a role of plate pressing.

  This pressing force is preferably a pressing force that suppresses the fluctuation of the forming plate 1 and keeps the clearance c between the upper die 3 and the lower die 4 at the time of shear cutting without fluctuation. . This is because the burr of the cut surface 5 is mainly caused by the fluctuation of the molded plate 1 at the start of shear cutting where the upper mold 3 and the lower mold 4 bite into the molded plate.

In shear cutting late 3 from shear cutting the initial 2, a cutting edge R ₁ of the upper mold 3, the cutting edge R ₂ of the lower die 4, there is a respective 80 to 300 [mu] m range. Thus, the cutting edge R ₁ of the upper die 3, and is relatively slow and the cutting edge R ₂ of the lower die 4, to crack the 6000-based cutting surface 5 of an aluminum alloy molded sheet 1, an aluminum alloy molding The amount of shearing blade biting into plate 1 increases. As a result, it is possible to suppress the cut surface 5 of the plate from having a shape in which chips are likely to be produced, and to suppress the generation of chips.

(Bottom 2a of pad 2)
At this time, the pad 2 applies a pressing force to the molding plate 1 at the same time when the bottom surface 3a of the upper mold 3 contacts the molding plate 1 or at a slightly earlier timing than that. It is effective in suppressing. By applying a pressing force to the forming plate 1 at this timing, the amount of biting of the shearing blade into the forming plate 1 until the cut surface 5 of the forming plate 1 is cracked increases. As a result, it is possible to suppress the cut surface 5 of the plate from having a shape in which chips are likely to be produced, and to suppress the generation of chips.

  When the pressing force applied to the plate by the bottom surface 2a of the pad 2 is delayed and shear cutting of the formed plate 1 is started, if sufficient pressing force is applied to the aluminum alloy formed plate 1, There is a possibility of burr on the cut surface (end face) 5.

  In order to apply the pressing force of the pad 2 to the molding plate 1 at the same time when the bottom surface 3a of the upper mold 3 contacts the molding plate 1 or slightly earlier than that, the bottom surface 2a of the pad 2 It is preferable that the mold 3 protrudes from the upper surface of the molding plate 1 to be sheared by a distance indicated by a in FIG. In other words, the bottom surface 2a of the pad 2 is preferably located below the bottom surface 3a of the upper mold 3 by a distance a and close to the top surface of the aluminum alloy molded plate 1. .

  The distance a of the bottom surface 2a of the pad 2 (soft pressing member) is preferably in the range of 0.1 to 0.5 mm. The reason why the range is 0.1 to 0.5 mm is to produce an action that produces the optimum timing for applying the pressing force. If the distance a is less than 0.1 mm, the aluminum alloy molded plate 1 is sufficiently pressed from the contact of the bottom surface 2a of the pad 2 with the upper surface of the aluminum alloy molded plate 1 using the pad 2 or its bottom surface 2a as a relatively hard material. Even if the timing is advanced, the timing of pressing the plate is not in time for the shear cutting start of the aluminum alloy molded plate 1 due to the lowering and contacting of the upper die 3. In addition, since the bottom surface 2a of the pad 2 is made of a relatively hard material, the surface of the molded plate is easily damaged. Therefore, the distance a is preferably set to 0.1 mm or more.

  On the other hand, when the distance a exceeds 0.5 mm, it takes a long time to press the aluminum alloy forming plate 1 until the shear cutting by the lowering of the upper die 3 even if the pad 2 or its bottom surface 2a is made of a relatively soft material. Become. For this reason, there is a high possibility that an indentation or a dent due to the pad 2 is generated on the surface of the soft aluminum alloy molded plate 1. Such indentations and dents, depending on the area of the bottom surface 2a of the pad 2, are emphasized by the metallic luster peculiar to the aluminum alloy, whether or not the surface treatment is used. It becomes conspicuous as a large difference in glossiness, and the value of the molded product is significantly impaired.

  The pad 2 needs to have a certain degree of hardness to ensure the sufficient pressing force. For this reason, as the pressing time becomes longer, the surface of the aluminum alloy molded plate 1 has indentations and dents due to the pad 2. Is more likely to occur. Therefore, in order to shorten the time for pressing the aluminum alloy molded plate 1 by the pad 2 as much as possible, the distance a is preferably 0.5 mm or less.

(Pad 2 bottom 2a hardness)
The effect of the optimum timing of applying the pressing force and the magnitude of the pressing force sufficient to suppress the fluctuation of the molding plate is also affected by the hardness of the bottom surface 2a of the pad 2 which is a soft pressing member. In this regard, if the hardness of the bottom surface 2a of the pad 2 is in the range of 20 to 60 Hv in terms of Vickers hardness, the effects of the above optimum timing of applying the pressing force and the magnitude of the pressing force are further exhibited.

  If the hardness of the bottom surface 2a of the pad 2 is less than 20 Hv, when the pad bottom surface 2a satisfies the distance a within the range of the present invention, depending on the trimming die conditions and shear cutting conditions, that is, the shear cutting is performed more. In difficult conditions, the pad 2 or its bottom surface 2a becomes too soft. For this reason, even if the bottom surface 2a of the pad 2 contacts the upper surface of the aluminum alloy molded plate 1 quickly, it takes time to sufficiently press the aluminum alloy molded plate 1 due to compression of the soft bottom surface 2a. There is a possibility that the timing of the plate pressing may not be in time for the start of shear cutting by descent and contact.

  On the other hand, when the hardness of the bottom surface 2a of the pad 2 exceeds 60 Hv, the surface of the molding plate 1 is easily damaged when the pad bottom surface 2a satisfies the distance a within the range of the present invention.

  In the present invention, in order to ensure that the hardness of the bottom surface 2a of the pad 2 is in the above range, and to ensure the above-mentioned optimal timing of applying the above-mentioned pressing force and the amount of pressing force sufficient to suppress the variation of the above-mentioned forming plate. In addition, the material and thickness of the pad 2 itself or the bottom surface 2a of the pad 2 are preferably designed and configured. For example, in the present invention, it is recommended that the material of the bottom surface 2a of the pad 2 be a soft resin such as urethane or felt, a foamed resin, or a cloth so that the pad hardness is in the above range. However, for the material of the bottom surface 2a, the body of the pad 2 that supports the bottom surface 2a may be the same material, another soft material, a metal such as steel, or a hard resin.

  In the present invention, as in the normal shearing process, the angle formed between the surface of the forming plate portion to be sheared and the moving direction of the upper blade is 90 °, and the forming plate is sheared in a direction perpendicular to the surface. However, with respect to the aluminum alloy forming plate 1b on the molded product side, the aluminum alloy forming plate 1a on the scrap side is moved downward at an angle of 50 to 80 ° with respect to the moving direction of the upper blade 3 on the cut surface 5. After bending, trimming may be performed by shearing the upper blade 3 and the lower blade 4. With this configuration, the aluminum alloy molded plate 1a on the scrap side is inclined at the above angle with respect to the moving direction (vertically downward) of the upper mold 3, so that the upper mold 3 is lowered and raised. Even if the shearing operation is reciprocated once, the fluctuation of the plate is suppressed, and the occurrence of burr on the cut surface 5 on the molded product side can be prevented or suppressed.

  In addition to the above description, in the present invention, there is basically no need to change the structure of a normal or conventional trimming apparatus, trimming mold, shearing conditions or method. This point is also an advantage of the present invention.

  The aluminum alloy molded plate 1 to be trimmed in the present invention refers to a material aluminum alloy plate formed into a product shape. Therefore, it can include not only a molded plate formed into a three-dimensional shape by press molding or bending, but also a plate as a raw material or a flat molded plate cut from a coil.

Hereinafter, a flat 6000 series aluminum alloy molded sheet 1, in practice, as shown in Table 1, the cutting edge R ₁ of the upper mold 3 was variously changed and cutting edge R ₂ of the lower die 4, in FIG. 1 Tests and investigations were made on the occurrence of chips when shear cutting was performed using the trimming mold shown. FIG. 4 is a plan view showing the dimensions of the 6000 series aluminum alloy molded plate 1 to be shear-cut, and FIG. 5 is a perspective view showing the dimensions of the plate presser pad 2 in FIG.

  In the 6000 series aluminum alloy forming plate 1 in FIG. 4, 1b is a forming portion (length 200 mm, width 300 mm), and 1a is an edge portion (remaining portion) removed by trimming. The edge portion 1a has a width of 30 mm at the four side portions of the molding portion 1b, and further has a rectangular trimming portion with a side of 30 mm at the four corner portions of the molding portion 1b. The molded plate 1 is a 6000 series aluminum alloy made of AA 6022-T4 material and has a thickness of 1 mm.

  The upper mold 3 and the lower mold 4 of FIG. 1 used for shear cutting have a planar shape of a cut surface corresponding to the outer edge shape of the molded part 1b, and are made of JIS FCD-55 mold steel. The clearance c between the blade surfaces 4b and 3b was 1 mm, which is 10% of the plate thickness.

  The pad 2 shown in FIG. 5 has a rectangular shape with an area that can hold almost the entire surface of the molded part 1b shown in FIG. 4 and has a thickness of 30 mm. In this shape, a pad made of an urethane resin including the bottom surface 2a was used. Further, the hardness of the bottom surface 2a was 40 Hv, and the downward protruding amount a was 0.2 mm.

For each of the same conditions (1 condition), 10 trimming tests (10 times) were performed, and the amount of biting (mm) of the shearing blade when the plate cut surface 5 was cracked when trimming was performed. The average of the amount of chips generated per 1 m ^{2 of the} molded plate (mg / m ² ) was obtained. The cut powder was collected by sucking the cut surface during cutting and measuring the weight. These results are shown in Table 1. In addition, when a shear failure occurred such as the plate could not be sheared even once during the test, the subsequent test was stopped and it was evaluated that shearing was impossible.

As shown in Table 1, Inventive Example 1-5, the cutting edge R of the shearing blades, the cutting edge R ₁ of the upper die 3, and a cutting edge R ₂ together 80 to 300 [mu] m in the range of the lower mold 4 . As a result, compared with Comparative Examples 6 to 11 outside this range, the amount of biting of the shearing blade (mm) when the plate cut surface 5 was cracked was large, and the amount of chips generated (mg / m ² ) was also high. It is running low.

On the other hand, in Comparative Examples 6 to 11, including Comparative Example 6 which is the cutting edge R of the shearing blade when sharpening, the amount of biting (mm) of the shearing blade is smaller than that of Invention Examples 1 to 5. The amount of chips generated (mg / m ² ) has also increased. Further, in Comparative Examples 12 and 13, since the cutting edge R 1 of the shearing blade was too large, a shear failure occurred, and the shearing could not be reliably performed.

  From the above results, the critical significance for the effect of suppressing the generation of chips within the specified range of the cutting edge R of the shearing blade of the present invention can be understood.

  As described above in detail, according to the present invention, it is possible to provide a method for trimming a 6000 series aluminum alloy formed plate that can easily and reliably suppress generation of chips. Therefore, the present invention can be applied to the manufacturing process of automobile panels and parts thereof, electrical equipment panels, precision parts, and the like that press-form 6000 series aluminum alloy plates.

It is a schematic diagram which shows the trimming apparatus of the aluminum alloy plate which concerns on embodiment of this invention. It is a schematic diagram which shows the initial trimming state of the trimming apparatus of FIG. It is a schematic diagram which shows the latter stage trimming state of the trimming apparatus of FIG. It is a top view which shows the shaping | molding board trimmed. It is a perspective view which shows a board pressing member. It is a schematic diagram which shows the conventional trimming apparatus. It is explanatory drawing which each shows the amount of biting of the shearing blade when the aluminum alloy plate and the mild steel plate are trimmed under the same conditions and the plate is cracked.

Explanation of symbols

1, 7; aluminum alloy molded plate, 2, 8; plate pressing member,
3, 9; Upper mold (upper blade) 4, 10; Lower mold (lower blade) 5; Molded plate cutting surface 6; Support frame, R ₁ ; Cutting blade R, R _{2 of} upper mold 3; Lower mold 4 Cutting edge R

Claims (3)

  In the method of trimming a 6000 series aluminum alloy molded plate after forming by shearing between the upper blade and the lower blade, each cutting edge R of the upper blade and the lower blade should be in the range of 80 to 300 μm. A trimming method of a featured aluminum alloy molded plate.   The aluminum alloy molded plate trimming method according to claim 1, wherein a thickness of the 6000 series aluminum alloy plate is 2 mm or less. The method for trimming an aluminum alloy molded plate according to claim 1 or 2, wherein the upper blade and the lower blade are sharpened and polished so that each cutting edge R is in the range of 80 to 300 µm.

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