JP7229470B2 - METHOD FOR MANUFACTURING METAL PLATE LAMINATED PRODUCT - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a laminate of metal plates by punching and laminating metal plates in a work holding hole of a die, irradiating the side surface of the metal plates with a laser beam, and welding the plates together in the die.

The corner of the upper end surface of the lower die outer shell punching hole in the stacking die inside the metal plate punching die of a predetermined shape is used as a cutting edge, and the side surface is used as a work holding hole, and a thin line is formed at a short distance from the cutting edge in the stacking direction of this work holding hole. A metal plate laminate manufacturing method in which a hole is provided to expose the side surface of a metal plate, a laser beam is irradiated to the side surface of the metal plate by a laser beam welding mechanism, and the plates are welded together in the mold. It is known as the inner laser welded sheet laminate manufacturing method. For example, Patent Literature 1 and Patent Literature 2 describe techniques for laser-welding the side surfaces of laminated metal plates, although it is not explicitly stated that they are in a mold.

In the general method of manufacturing in-mold laser welded metal plate laminates, the laser beam used for welding is oscillated by an excitation lamp and a rod in the laser machine body, split into 2 to 6, and condensed by a lens to enter each optical fiber. The light is radially emitted from the exit of the optical fiber in each output unit mounted in the punching die, and then parallelized by the lens and condensed to the processing position by the lens again. Both lenses and optical fibers have the same circular shape, and the processing position of the laser beam is also circular. The diameter of the optical fiber is typically 0.6 mm due to practical focusing precision constraints of the entrance lens. The diameter of the processing position of the laser beam is slightly larger than the diameter of the optical fiber, and is 0.8 to 0.9 mm at the minimum, because of the practical focusing accuracy of the lens at the exit.

Although an optical fiber with a diameter of 0.4 mm is also used for a laminated product of small thin and thick metal plates, the accuracy of light collection at the entrance is strictly controlled. If the accuracy is out of order and the entrance of the optical fiber is burned out, it will need to be repaired, and the cost is close to the purchase price, so it is avoided at the actual production site.

In addition, deep penetration for securing welding strength cannot be adopted because it causes welding defects such as spatter and blowholes. Welding with a large amount of extracted oil in the mold causes intense vaporization, so it is necessary to make the welding depth shallow in order to quickly release this from the molten pool into the atmosphere and achieve the good welding and appearance required by the product. From the above, general spot welding has a pot shape with a diameter of 0.8 to 0.9 mm and a depth of about 0.3 mm.

Now, the method of separating the laser-welded metal plate laminate in the mold, in which the plates are punched out in order, into upper and lower units is performed while the welding is stopped, but the combined thickness of the plates to be welded is 1.0 mm. Considering that the welding position shifts due to variations in the thickness of the laminated plates, the diameter is made slightly larger than the spot welding diameter so that the separation is ensured and the upper and lower plates are not welded. The thickness of one sheet that can be separated by basic two-sheet welding is 1.0/2, which is 0.5 mm or more. The plate thickness is 0.35 mm (1.05 mm) when three plates are welded.

1 and 2 are welding diagrams of metal plate laminates of the prior art, and the diameter of the spot welding circle 33 is all 0.8-0.9 mm. In the laminated product with a plate thickness of 0.5 mm in FIG. 1, the welding center 34 is set at the center between the plates, and even if the position of the welding center 34 moves by 0.1 mm due to the plate thickness variation, the separation of the product can be performed without any problem. Strength is also ensured. In the laminated product with a plate thickness of 0.35 mm in FIG. is also ensured.

However, recent metal plate laminates, especially in the electromagnetic cores made by laminating electromagnetic steel sheets used in motors, etc., have been made thinner in order to improve electrical performance. there is Moreover, since the overall size and weight of the core remains the same as before, the welding strength must be the same as before.

In the welding diagram of the metal plate laminate with a plate thickness of 0.2 mm in FIG. 0 mm) welding, the position of the welding center 34 is set at the center of the center plate of the five plates, and the required welding strength cannot be obtained at the separated laminate end plate 10 because the weld length is shorter than the center plate. In particular, when the position of the welding center moves by 0.05 mm, the welding length of the laminate end plate 10 is reduced to half or less.

JP-A-7-255151 JP-A-9-149605

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for producing a metal plate laminate that can obtain the required welding strength even when the metal plate is thinned to 0.35 mm to 0.2 mm .

The present invention, which has been made in order to solve the above-mentioned problems, has a cutting edge at the upper end surface corner of a lower die outer shell punched hole of a metal plate punching die with a predetermined shape, and a work holding hole at the side surface. A small hole is made close to the cutting edge in the stacking direction of the workpiece holding hole to expose the side of the metal plate, and a laser beam is applied to the side of the metal plate by a laser beam welding mechanism in which a condenser lens is installed in the mold. In the manufacturing method of metal plate laminates in which the plates are welded together in a mold by irradiation, the plate thickness of the metal plates is 0.35 mm to 0.2 mm, and spot welding circular plate lamination at the processing position of the laser beam. It is characterized by shortening the upper and lower parts in the direction.

In the present invention, before the laser beam is focused on the processing position with a lens , a shield is placed above and below the laser beam to absorb a part of the energy, thereby weakening the strength and not welding, and processing the laser beam. It is possible to shorten the upper and lower parts of the plate lamination direction of the spot welding circular shape of the position.

According to the method for manufacturing a metal plate laminated product according to the present invention, shields are installed above and below the laser beam, and part of the energy is absorbed to weaken the strength and prevent welding. Freely shorten the welding length. Therefore, in the present invention, the required welding strength of the metal plate laminate can be ensured, thereby eliminating the weakly welded laminate end plate 10 shown in FIG .

FIG. 2 is a weld diagram of a prior art example of an in-mold laser welded metal plate laminate with a plate thickness of 0.5 mm. FIG. 2 is a weld diagram of a prior art example of a laser welded metal plate laminate in a mold having a thickness of 0.35 mm. Welding diagram of an in-mold laser-welded metal plate laminate of a prior art example of a new thin plate material. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall schematic cross-sectional view of an in-mold laser-welded metal plate lamination method of Example 1 of the present invention. FIG. 2 is a welding drawing of an in-mold laser-welded metal plate laminate of Example 1 of the present invention of the new thin plate material.

Embodiment 1 of the present invention will be described below with reference to FIGS. 4 and 5. FIG .
FIG. 4 is a sectional view showing an in-mold laser-welded metal plate laminating apparatus. Reference numeral 13 denotes an upper shell punch that constitutes a laminated mold inside the metal sheet punching die, and 14 a lower mold shell punching die. A lower die contour punching hole 15 is formed in the lower die contour punching die 14, and a cutting edge 16 is formed at the corner of the upper end face.

A metal plate 11 having a predetermined shape is punched out from a material plate 12 by an upper mold contour punch 13 and a lower mold contour punch die 14, and a side surface 15 of the contour punch hole is used as a work holding hole. The workpieces are stacked one on another while being in close contact with each other inside the holding hole, and when they reach the lower end of the workpiece holding hole, they are dropped and taken out.

A small hole 17 is provided at a short distance from the die cutting edge 16 of this work holding hole, the side surface of the metal plate 11 is exposed, and a laser beam is irradiated in the mold by a laser beam welding mechanism to weld the plates together. .

The laser beam welding mechanism irradiates the rod 18 with light from the excitation lamp 19, takes out the laser beam 20, splits it with the branching mirror 21, and focuses it on the entrance of the optical fiber 23 with the lens 22, but the practical focusing accuracy is limited. The laser beam is passed through an optical fiber 0.6 mm in diameter to an emission unit mounted in the mold. It is a structure for condensing light to a processing position 26 on the side surface of the .

In the present invention, the upper and lower portions of the spot-welded circular plate stacking direction at the processing position of the laser beam are shortened according to the plate thickness of 0.35 mm to 0.2 mm . For this reason, before focusing on the processing position, the upper and lower parts of the laser beam are shielded to absorb part of the energy and weaken the strength to prevent welding. The upper and lower parts of the circular plate stacking direction are shortened. That is, the shields 31 and 32 for shortening the stacking direction of the laser beam are placed behind the lens 25 for condensing the laser beam to the processing position, and absorb part of the energy of the upper and lower laser beams. These shields 31 and 32 are made of aluminum, which easily absorbs the laser beam, and the surface of which is blackened by alumite processing (anodization treatment) to absorb light and release it as heat.

The laser beam is irradiated in accordance with the timing of removing the mold. The metal sheet laminate 27 shown in FIG. 4 is separated into single pieces. Separation is performed by stopping the irradiation welding of the laser beam at the timing of separation so as not to weld between the metal plates 11 .

FIG. 5 is a welding diagram of a metal plate laminate with a plate thickness of 0.2 mm according to the present invention. Set at the center of the plate thickness. As shown in FIG. 3 of the prior art, five plates are required to be joined together for separation. No obstacles.

As described above, according to the present invention, by shortening the upper and lower parts of the spot welding circular plate stacking direction at the processing position of the laser beam according to the plate thickness of 0.35 mm to 0.2 mm , the required welding Strength can be obtained.

10 Laminated product end plate 11 Metal plate of predetermined shape 12 Material plate 13 Upper mold contour punch 14 Lower mold contour punch die 15 Side face of contour punch hole 16 Die cutting blade 17 Fine hole 18 for exposing metal plate and passing laser beam 18 Rod 19 Excitation lamp 20 Laser beam 21 Diverting mirror 22 Optical fiber input lens 23 Optical fiber 24 Optical fiber radiation parallel lens 25 Processing position condenser lens 26 Processing position on side of metal plate 27 Metal plate laminate 31 Upper fixed shield 32 Lower fixed shield 33 Spot welding circle 34 Welding center

Claims (2)

The corner of the upper end surface of the lower die outer shell punching hole in the stacking die inside the metal plate punching die of a predetermined shape is used as a cutting edge, and the side surface is used as a work holding hole, and a thin line is formed at a short distance from the cutting edge in the stacking direction of this work holding hole. A metal that exposes the side of a metal plate by making a hole and irradiates the side of the metal plate with a laser beam using a laser beam welding mechanism in which a condensing lens is installed in the mold to weld the plates together in the mold. In the method for manufacturing a laminated plate product,
A method for manufacturing a laminated metal plate product, characterized in that the plate thickness of the metal plate is set to 0.35 mm to 0.2 mm, and the upper and lower portions of the plate lamination direction of the spot-welded circular shape at the processing position of the laser beam are shortened. Shortening the upper and lower parts of the spot welding circular plate stacking direction at the processing position of the laser beam by installing a shield on the upper and lower parts of the laser beam before focusing on the processing position to absorb part of the energy. The method for manufacturing a metal sheet laminate according to claim 1, characterized by:

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