Method for cutting unnecessary parts of die-cast products and die-cast products

Abstract

To cut an unnecessary part easily from a die-cast product.SOLUTION: This invention relates to a method for cutting an unnecessary part 3 from a product part 2 of a cast die-cast product 1, wherein: the product part 2 has a first piece 21 and a second piece 22 which is folded in a mountain fold with respect to the first piece 21 and extends from one end of a first direction 101 of the first piece 21; and the unnecessary part 3 has protruding pieces 31, 32 protruding in a second direction at least at one of one end of a second direction 102 orthogonal to the first direction 101 in the first piece 21 and one end of the second direction 102 in the second piece 22. The method includes a cutting step of cutting the unnecessary part 3 by emitting a laser 10 from the mountain fold side, wherein the cutting step includes a step of cutting the protruding pieces 31, 32 by advancing the laser 10 in a direction closer to a connection part 27 of the first piece 21 and the second piece 22.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for cutting off an unnecessary portion from a die-cast product after casting, and to a die-cast product from which an unnecessary portion has been cut off. [Background technology]

[0002] A die-cast product has unnecessary parts such as a runner. In the following Patent Documents 1 to 3, the unnecessary parts such as the runner are trimmed by a press. However, depending on the shape of the die-cast product, pressing may be impossible or difficult. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 63-132731 [Patent Document 2] Japanese Utility Model Application Publication No. 5-88755 [Patent Document 3] Japanese Patent Application Publication No. 6-15316 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to make it possible to easily cut off unnecessary portions from a die-cast product. [Means for solving the problem]

[0005] The method for cutting an unnecessary portion of a die-cast product of the present invention is a method for cutting an unnecessary portion from a product portion of a cast die-cast product, wherein the product portion has a first piece and a second piece bent in a mountain fold relative to the first piece and extending from one end of the first piece in a first direction, and the unnecessary portion has a protruding piece protruding in the second direction from at least one of one end of the first piece in a second direction perpendicular to the first direction and one end of the second piece in the second direction, and the method includes a cutting step of irradiating a laser from the mountain fold side to cut the unnecessary portion, and the cutting step includes a step of advancing the laser in a direction approaching the connection portion between the first piece and the second piece to cut the protruding piece.

[0006] The second piece in the die-cast product is bent relative to the first piece. The first piece or the second piece is provided with a protruding piece as an unnecessary part. The protruding piece is, for example, a runner part. Since the second piece is bent relative to the first piece, it is difficult to trim the protruding piece by pressing. In the above method, the protruding piece is irradiated with a laser to melt and cut the protruding piece. In addition, by irradiating the laser from the mountain fold side instead of the valley fold side, the protruding piece can be easily irradiated with the laser. Then, the protruding piece can be cut by the laser without contact. Therefore, excessive force is not applied to the product part, and there is no risk of the product part being deformed as in the case of pressing, and the protruding piece can be easily cut off and removed from the product part.

[0007] On the other hand, when the protruding piece is irradiated with a laser, the cut portion of the protruding piece melts, and molten metal (spatter) splashes on the side opposite to the laser irradiation side. Because the first piece and the second piece are bent toward each other, there is a risk that the molten metal will adhere to the fold side of the first piece or the second piece. For example, when cutting the protruding piece of the first piece, there is a risk that the molten metal will adhere to the second piece, and when cutting the protruding piece of the second piece, there is a risk that the molten metal will adhere to the first piece. If the molten metal adheres to the first piece or the second piece, it may result in a defective product.

[0008] In the above method, when cutting the protruding piece with a laser, the laser is advanced in a direction toward the connection part, rather than in a direction away from the connection part between the first piece and the second piece. When the laser is advanced in a direction away from the connection part between the first piece and the second piece, the molten metal is more likely to fly toward the connection part behind the direction of laser advancement. In other words, when cutting the protruding piece of the first piece, the molten metal is more likely to fly toward the second piece, and when cutting the protruding piece of the second piece, the molten metal is more likely to fly toward the first piece. On the other hand, when the laser is advanced in a direction toward the connection part, the molten metal is more likely to fly toward the opposite side of the connection part and is less likely to be directed toward the first piece or the second piece. Therefore, the molten metal is less likely to adhere to the first piece or the second piece. The direction in which the molten metal flies varies depending on various conditions such as the laser output, irradiation time, moving speed, and irradiation angle. However, compared to when the laser is advanced in a direction away from the connection part, by advancing the laser in a direction toward the connection part, the molten metal is less likely to fly toward the connection part, and the molten metal can be prevented from adhering to the first piece or the second piece.

[0009] In addition, the method for cutting an unnecessary portion of a die-cast product of the present invention is a method for cutting an unnecessary portion from a product portion of a cast die-cast product, wherein the product portion has a first piece and a second piece bent in a mountain fold relative to the first piece and extending from one end of the first piece in a first direction, and the unnecessary portion has a protruding piece protruding in the second direction from at least one of one end of the first piece in a second direction perpendicular to the first direction and one end of the second piece in the second direction, and the method includes a cutting step of irradiating a laser from the mountain fold side to cut off the unnecessary portion, and the cutting step includes a step of advancing the laser in a direction away from the connection portion between the first piece and the second piece and irradiating the laser diagonally from the rear side to the front side in the direction of advancement to cut off the protruding piece.

[0010] According to this method, when cutting the protruding piece with a laser, the laser is advanced in a direction away from the connection part. As described above, when the laser advances in a direction away from the connection part, the molten metal is likely to fly toward the connection part. In this case, the laser is not irradiated at a right angle to the protruding piece, but is irradiated at an angle. That is, the laser is irradiated at an angle from the rear side to the front side in the advancement direction to the protruding piece. When the laser is irradiated at an angle in this manner, the surface on the opposite side to the laser irradiation side (the surface on the valley fold side) can be melted before the surface on the laser irradiation side (the surface on the mountain fold side) at the end of the protruding piece on the cutting start side. Then, the melted portion can be expanded to the surface on the laser irradiation side. Therefore, compared to when the laser irradiation angle is at a right angle, the molten metal is less likely to fly backward in the laser advancement direction, and the molten metal is less likely to adhere to the first piece or the second piece.

[0011] In addition, the method for cutting an unnecessary portion of a die-cast product of the present invention is a method for cutting an unnecessary portion from a product portion of a cast die-cast product, wherein the product portion has a first piece, a second piece extending from one end of the first piece in a first direction, bent in a mountain fold relative to the first piece, and a third piece extending from the other end of the first piece in the first direction, and the unnecessary portion has a first protruding piece protruding in a second direction from one end of the first piece in a second direction perpendicular to the first direction, and the cutting process includes a cutting step of irradiating a laser from the mountain fold side to cut the unnecessary portion, and the cutting step includes a step of irradiating the laser obliquely from the rear side to the front side in the direction of travel to cut the first protruding piece.

[0012] According to this method, when cutting the first protruding piece, the laser is irradiated obliquely from the rear side to the front side in the traveling direction of the first protruding piece, which makes it difficult for the molten metal to splash toward the second piece or the third piece, and makes it difficult for the molten metal to adhere to the second piece or the third piece.

[0013] In particular, it is preferable that the unnecessary portion has a second protruding piece protruding in the second direction from one end of the second piece in the second direction, and the cutting step includes a step of advancing the laser in a direction approaching the connection portion between the first piece and the second piece to cut the second protruding piece. This makes it difficult for the molten metal to head toward the first piece and adhere to the first piece when cutting the second protruding piece.

[0014] Preferably, the unnecessary portion has a second protruding piece protruding in the second direction from one end of the second piece in the second direction, and the cutting step includes a step of cutting the second protruding piece by advancing a laser in a direction away from the connection portion between the first piece and the second piece and irradiating the laser obliquely from the rear side to the front side in the advancing direction. This makes it difficult for molten metal to head toward the first piece and adhere to the first piece when cutting the second protruding piece.

[0015] Furthermore, the die-cast product of the present invention is a die-cast product from which unnecessary portions have been cut off, and comprises a first piece and a second piece extending from one end of the first piece in a first direction, bending in a mountain fold relative to the first piece, and at least one of the one end of the first piece in a second direction perpendicular to the first direction and the one end of the second piece in the second direction is provided with a cut surface having a line-like laser cutting mark, and the laser cutting mark is a line that is inclined in a direction away from the other piece from the mountain fold surface toward the valley fold surface, or a line that is approximately perpendicular from the mountain fold surface toward the valley fold surface. Effect of the Invention

[0016] As described above, by melting and cutting the unnecessary parts without contact using a laser, restrictions on the shape of the die-cast product are reduced, and the unnecessary parts can be easily cut off without deforming the product. Furthermore, depending on the laser travel direction or the inclination with respect to the laser travel direction, adhesion of molten metal to the product part can be suppressed, and the occurrence of product defects can be suppressed. [Brief description of the drawings]

[0017] [Figure 1]4(a) and (b) are front views showing a cutting method in one embodiment of the present invention, and (c) is a front view showing a cut surface. [Diagram 2] 4(a) and (b) are front views showing the same cutting method, and (c) is a front view showing the cut surface. [Diagram 3] 4(a) and (b) are front views showing the same cutting method, and (c) is a front view showing the cut surface. [Figure 4] 4(a) and (b) are front views showing the same cutting method, and (c) is a front view showing the cut surface. [Diagram 5] FIG. 2A is a perspective view showing a state after casting of a die-cast product that is the target of a cutting method in one embodiment of the present invention, and FIG. 2B is a perspective view showing the die-cast product from which unnecessary portions have been cut off. [Figure 6] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 7] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 8] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 9] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 10] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 11] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 12] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 13] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 14] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 15] FIG. 11 is a perspective view showing a state after casting of a die-cast product that is a target of a cutting method in another embodiment of the present invention. [Figure 16]FIG. 4 is a perspective view showing the die-cast product after unnecessary portions have been removed. [Figure 17] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 18] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 19] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 20] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. [Figure 21] 4(a) is a front view showing the same cutting method, and (b) is a front view showing the die-cast product after cutting. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, a method for cutting off an unnecessary portion of a die-cast product according to one embodiment of the present invention and the die-cast product from which the unnecessary portion has been cut off will be described with reference to the drawings. The die-cast product 1 is composed of a product portion 2 and an unnecessary portion 3, and the cutting method involves cutting off the unnecessary portion 3. First, the basic principle of the cutting method will be described.

[0019] 1 to 4 show a conceptual diagram of a cutting method. In the cutting method, a laser 10 is irradiated onto a protruding piece 4 as an unnecessary part 3, and the protruding piece 4 is cut by the laser 10. FIG. 1 to FIG. 4 show the protruding piece 4 as seen from the tip side in the protruding direction. The protruding piece 4 is plate-shaped with a first surface 4a and a second surface 4b as plate surfaces. The laser 10 is irradiated onto the protruding piece 4 from the first surface 4a side. That is, the first surface 4a is the surface on the laser irradiation side, and the second surface 4b is the surface on the opposite side to the laser irradiation side. FIG. 1 and other figures show a torch 11 (nozzle) for irradiating the laser 10. The laser 10 is irradiated from the tip of the torch 11. Air is supplied inside the torch 11. Therefore, air is sprayed from the tip of the torch 11 together with the laser 10.

[0020] In FIG. 1, the laser 10 is irradiated to the left end 4d (one end in the traveling direction) of the protruding piece 4. The arrow A shown in FIG. 1 indicates the traveling direction (scanning direction) of the laser 10. In FIG. 1, the laser 10 travels from the left side to the right side of the paper. The laser 10 is irradiated to the protruding piece 4 from the first surface 4a side of the protruding piece 4. The torch 11 is perpendicular to the traveling direction. The laser 10 is irradiated perpendicularly toward the first surface 4a of the protruding piece 4. As shown in FIG. 1(a), the laser 10 is irradiated perpendicularly to the first surface 4a at the left end 4d of the protruding piece 4, so that the left end 4d of the protruding piece 4 starts to melt from the first surface 4a side.

[0021] As shown in FIG. 1(b), the melting of the left end 4d of the protruding piece 4 progresses from the first surface 4a side to the second surface 4b side, and the melted portion 5 of the protruding piece 4 expands to the right as the torch 11 is moved to the right. In the figure, the melted portion 5 is indicated by a number of dots. The protruding piece 4 melts first on the first surface 4a side, and then on the second surface 4b side. Therefore, the molten metal 6 (spatter) flies diagonally to the left as shown in FIG. 1(b). That is, the molten metal 6 flies diagonally from the first surface 4a side to the second surface 4b side and backward with respect to the traveling direction of the laser 10. The angle at which the molten metal 6 flies varies depending on the output of the laser 10, the irradiation time, the moving speed of the laser 10, and the like.

[0022] FIG. 1(c) shows the cut surface 7 after the protruding piece 4 has been cut off. On the cut surface 7, a trace of the protruding piece 4 melted by irradiation and scanning with the laser 10 remains as a laser cut mark 8. The laser cut mark 8 is streak-like, and the direction of the streak is close to the direction in which the molten metal 6 moves. In this example, as described above, the molten metal 6 moves diagonally leftward and downward. Therefore, the streak of the laser cut mark 8 is inclined leftward and downward when viewed from the front. In other words, the streak of the laser cut mark 8 is inclined backward in the traveling direction of the laser 10, from the first surface 4a to the second surface 4b.

[0023] FIG. 2 shows a case where the torch 11 is moved from the right end 4c of the protruding piece 4 to the left side in the opposite direction to FIG. 1 to cut the protruding piece 4. In this case as well, melting starts from the first surface 4a side of the right end 4c as shown in FIG. 2(a), and then the melted portion 5 gradually expands to the second surface 4b side. At the same time, as shown in FIG. 2(b), the torch 11 advances to the left, so that the melted portion 5 expands to the left on the first surface 4a side before the second surface 4b side, while the second surface 4b side melts later. Therefore, the molten metal 6 flies diagonally to the right as shown in FIG. 2(b). That is, the molten metal 6 flies diagonally from the first surface 4a side to the second surface 4b side and backward with respect to the traveling direction of the laser 10.

[0024] 2(c) shows the cut surface 7 after the protruding piece 4 is cut off. In this example, the molten metal 6 flows diagonally to the right as described above. Therefore, the streaks of the laser cut marks 8 are inclined to the right and downward when viewed from the front. In other words, the streaks of the laser cut marks 8 are inclined backward in the traveling direction of the laser 10 from the first surface 4a to the second surface 4b.

[0025] On the other hand, the laser 10 can also be irradiated from an inclined direction rather than perpendicular to the protruding piece 4. In that case, the molten metal 6 can be thrown in a direction different from that in the case where the laser 10 is irradiated perpendicularly to the protruding piece 4.

[0026] In FIG. 3, the torch 11 is tilted from a perpendicular state to the traveling direction to the rear side of the traveling direction. The traveling direction of the laser 10 is from the left side to the right side. The laser 10 is irradiated obliquely from the rear side to the front side of the traveling direction. That is, the laser 10 is irradiated obliquely from the left side to the right side. As shown in FIG. 3(a), the laser 10 is first irradiated to the left end 4d (left side surface) of the protruding piece 4. More specifically, the laser 10 is first irradiated to the second surface 4b side of the left end 4d of the protruding piece 4, not the first surface 4a side. Therefore, the second surface 4b side of the left end 4d of the protruding piece 4 starts to melt before the first surface 4a side. Then, as shown in FIG. 3(b), the laser 10 moves to the right side, and the molten portion 5 expands from the second surface 4b side to the first surface 4a side of the left end 4d of the protruding piece 4. As a result, the molten metal 6 is less likely to fly to the rear side of the traveling direction of the laser 10 compared to when the laser 10 is irradiated at a right angle. FIG. 3(b) shows, as an easy-to-understand example, a state in which the molten metal 6 flies in an approximately straight line from the first surface 4a side to the second surface 4b side, but the direction in which the molten metal 6 flies varies depending on the output of the laser 10, the irradiation time, the movement speed of the laser 10, etc.

[0027] 3(c) shows the cut surface 7 after the protruding piece 4 is cut off. In this example, as an easy-to-understand example, a case is shown in which the molten metal 6 flows in a substantially straight line from the first surface 4a side to the second surface 4b side. In this case, the streaks of the laser cutting marks 8 are substantially vertical when viewed from the front. That is, the streaks of the laser cutting marks 8 are substantially vertical streaks from the first surface 4a to the second surface 4b.

[0028] In FIG. 4, the torch 11 is tilted from a perpendicular state to the traveling direction to the front side of the traveling direction, which is the opposite of FIG. 3. The traveling direction of the laser 10 is from left to right as in FIG. 3. The laser 10 is irradiated obliquely from the front side to the rear side of the traveling direction. As shown in FIG. 4(a), the laser 10 is irradiated to the first surface 4a of the left end 4d of the protruding piece 4. Therefore, the first surface 4a side of the left end 4d of the protruding piece 4 starts to melt before the second surface 4b side. Then, as the laser 10 moves to the right, the melted portion 5 of the protruding piece 4 expands to the right, and the melting at the left end 4d of the protruding piece 4 progresses from the first surface 4a side to the second surface 4b side. In other words, the first surface 4a side of the protruding piece 4 melts much earlier than the second surface 4b side, and the second surface 4b side melts much later. Therefore, the molten metal 6 flies obliquely to the left as shown in FIG. 4(b). This angle of inclination diagonally to the left will be even larger than that shown in FIG. 1(b) when the conditions such as the output of laser 10 are the same as in FIG. 1(b), and the ball will fly at an even greater angle diagonally to the left than in FIG. 1(b).

[0029] Fig. 4(c) shows the cut surface 7 after the protruding piece 4 is cut off. In this example, the molten metal 6 moves further left than in Fig. 1(b) as described above. The streaks of the laser cut marks 8 are inclined more significantly toward the left and downward side than in Fig. 1(c) when viewed from the front. The streaks of the laser cut marks 8 are inclined more significantly toward the rear side in the traveling direction of the laser 10, from the first surface 4a toward the second surface 4b.

[0030] Next, a further explanation will be given by giving a specific example of the die-cast product 1. Fig. 5(a) shows a schematic diagram of an example of the die-cast product 1 immediately after casting. Fig. 5(b) shows the die-cast product 1 in a state where the unnecessary portion 3 has been removed, i.e., only the product portion 2. In Fig. 5(b), a large number of dots are added to the cut surfaces (first cut surface 41, second cut surface 42) where the unnecessary portion 3 has been cut.

[0031] Immediately after casting, the die-cast product 1 has a waste portion 3 in addition to a product portion 2. The shape of the product portion 2 is arbitrary, but in this embodiment, the product portion 2 has a first piece 21 and a second piece 22. The first piece 21 and the second piece 22 are plate-shaped.

[0032] The two vertical and horizontal directions of the first piece 21 are defined as a first direction 101 and a second direction 102, respectively. The first direction 101 and the second direction 102 are perpendicular to each other. The plate thickness direction of the first piece 21 is defined as a third direction 103. The third direction 103 is perpendicular to the first direction 101 and the second direction 102. Hereinafter, the first direction 101 is defined as a left-right direction, and the left-right direction is defined based on the product part 2 viewed from the first end side of the second direction 102 as shown in FIG. 6 and the like. Therefore, the first end of the first direction 101 is the right end, and the second end of the first direction 101 is the left end. In addition, the second direction 102 is defined as a front-rear direction, and the first end side of the second direction 102 is defined as the front side. Therefore, the first end of the second direction 102 is the front end, and the second end of the second direction 102 is the rear end. Furthermore, the third direction 103 is defined as a top-bottom direction, and the direction in which the second piece 22 extends from the first piece 21 is defined as the bottom side. The first end in the third direction 103 is the top end, and the second end in the third direction 103 is the bottom end.

[0033] The first piece 21 extends horizontally, and the second piece 22 extends downward from a right end 21a of the first piece 21. The second piece 22 is bent in a mountain fold relative to the first piece 21 when viewed from above. In this embodiment, the second piece 22 is bent at a right angle relative to the first piece 21, but the bending angle is arbitrary. The right end 21a of the first piece 21 is a connecting end with the second piece 22, and the left end 21b of the first piece 21 is a free end. In addition, the upper end 22a of the second piece 22 is a connecting end with the first piece 21, and the lower end 22b of the second piece 22 is a free end.

[0034] The unnecessary portion 3 may have any shape, but in this embodiment, the unnecessary portion 3 has a first protruding piece 31 and a second protruding piece 32. Each of the protruding pieces 31 and 32 is plate-shaped. The protruding pieces are, for example, runner portions.

[0035] The first protruding piece 31 protrudes forward from the front end 21c of the first piece 21. The second protruding piece 32 protrudes forward from the front end 22c of the second piece 22. In this way, both the first protruding piece 31 and the second protruding piece 32 protrude forward from the product portion 2, but at least one of them may protrude rearward. The first protruding piece 31 is provided on a portion of the entire length of the front end 21c of the first piece 21, and the second protruding piece 32 is provided on a portion of the entire length of the front end 22c of the second piece 22.

[0036] Next, a method for cutting the first protruding piece 31 and the second protruding piece 32 will be described. Various cutting methods are shown in Figures 6 to 11. In Figures 6 to 11, the first piece 21 and the second piece 22 are shown as viewed from the front.

[0037] <Cutting method 1> An example of a cutting method is shown in Fig. 6(a). When cutting first protruding piece 31, torch 11 is placed above first protruding piece 31. When cutting second protruding piece 32, torch 11 is placed on the right side of second protruding piece 32. In this way, torch 11 is placed on the mountain fold sides of first piece 21 and second piece 22, respectively, and laser 10 is irradiated from the mountain fold sides.

[0038] When cutting the first protruding piece 31, the first protruding piece 31 is cut from its left end 31b toward its right end 31a. That is, the first protruding piece 31 is cut while moving the torch 11 to the right toward the connection portion 27 of the first piece 21 and the second piece 22. The torch 11 is set perpendicular to the first protruding piece 31 and perpendicular to the traveling direction. By setting the traveling direction of the laser 10 (the moving direction of the torch 11) to the direction approaching the connection portion 27 in this way, the molten metal 6 can be thrown diagonally toward the left side. That is, the molten metal 6 can be thrown in a direction away from the second piece 22, and the molten metal 6 can be prevented from adhering to the second piece 22. The angle at which the molten metal 6 is thrown varies depending on various conditions of the laser 10.

[0039] When cutting the second protruding piece 32, the second protruding piece 32 is cut from its lower end 32b toward its upper end 32a. That is, the torch 11 is moved upward so as to approach the first piece 21, that is, so as to approach the connection portion 27. The movement direction of the torch 11 is from the bottom side to the top side. The torch 11 is set perpendicular to the second protruding piece 32 and perpendicular to the traveling direction. By setting the traveling direction of the laser 10 to the direction approaching the connection portion 27 in this way, the molten metal 6 can be shot diagonally downward. That is, the molten metal 6 can be shot in a direction away from the first piece 21, and the molten metal 6 can be prevented from adhering to the first piece 21. In this case, the angle at which the molten metal 6 is shot varies depending on various conditions of the laser 10. It is to be noted that the order of cutting the first protruding piece 31 and the second protruding piece 32 may be any order.

[0040] FIG. 6(b) shows the die-cast product 1 after the first protruding piece 31 and the second protruding piece 32 are cut off. The front end 21c of the first piece 21 has a first cut surface 41 formed by cutting the first protruding piece 31. The front end 22c of the second piece 22 has a second cut surface 42 formed by cutting the second protruding piece 32. The streaks of the laser cut marks 8 on the first cross section 41 are inclined leftward and downward when viewed from the front. That is, the streaks of the laser cut marks 8 on the first cut surface 41 are inclined in a direction away from the second piece 22 from the mountain fold side surface (the surface on the laser irradiation side) to the valley fold side surface (the surface on the opposite side to the laser irradiation side) when viewed from the front. Also, the streaks of the laser cut marks 8 on the second cut surface 42 are inclined leftward and downward when viewed from the front. That is, the streaks of the laser cut marks 8 on the second cut surface 42 are inclined in a direction away from the first piece 21 from the mountain fold side surface to the valley fold side surface when viewed from the front. The inclination angle of the streak varies depending on various conditions of the laser 10.

[0041] <Cutting method 2> FIG. 7(a) shows an example of a cutting method. The cutting method of the first protruding piece 31 is the same as that shown in FIG. 6(a). The cutting method of the second protruding piece 32 is different from that shown in FIG. 6(a). That is, the second protruding piece 32 is cut from its upper end 32a to its lower end 32b, inversely to the case of FIG. 6(a). That is, the torch 11 is moved downward away from the first piece 21, that is, away from the connection part 27. The movement direction of the torch 11 is from the upper side to the lower side. The torch 11 is inclined so as to be tilted upward, which is the rear side of the traveling direction, rather than perpendicular to the second protruding piece 32. That is, the torch 11 is tilted upward at a predetermined angle, and the laser 10 is inclined obliquely from the upper side, which is the rear side of the traveling direction, to the lower side, which is the front side of the traveling direction, and irradiated to the second protruding piece 32. This allows the molten metal 6 to fly approximately perpendicular to the second piece 22, that is, approximately straight toward the left side. Therefore, the molten metal 6 is less likely to adhere to the first piece 21. The direction in which the molten metal 6 flies varies depending on the conditions of the laser 10, but here, the molten metal 6 flies in a substantially straight line toward the left side. Also, for example, after the first protruding piece 31 is cut, the second protruding piece 32 can be cut in a single stroke.

[0042] Fig. 7(b) shows the die-cast product 1 after the first protruding piece 31 and the second protruding piece 32 have been cut off. The streaks of the laser cutting marks 8 in the first cross section 41 are the same as those in Fig. 6(b). On the other hand, unlike those in Fig. 6(b), the streaks of the laser cutting marks 8 in the second cut surface 42 are approximately perpendicular to the second piece 22 and extend from the right side to the left side when viewed from the front. In other words, the streaks of the laser cutting marks 8 in the second cut surface 42 are approximately perpendicular from the surface on the mountain fold side to the surface on the valley fold side when viewed from the front.

[0043] <Cutting method 3> FIG. 8(a) shows an example of a cutting method. The cutting method of the second protruding piece 32 is the same as that shown in FIG. 7(a). The cutting method of the first protruding piece 31 is different from that shown in FIG. 7(a). That is, the first protruding piece 31 is cut from its right end 31a to its left end 31b, inversely to the case of FIG. 7(a). That is, the torch 11 is moved to the left so as to move away from the second piece 22, that is, away from the connection part 27. The movement direction of the torch 11 is from the right side to the left side. The torch 11 is not at a right angle to the first protruding piece 31, but is tilted so as to tilt to the right side, which is the rear side in the traveling direction. That is, the torch 11 is tilted to the right at a predetermined angle, and the laser 10 is tilted obliquely from the right side, which is the rear side in the traveling direction, to the left side, which is the front side in the traveling direction, and irradiated to the first protruding piece 31. This allows the molten metal 6 to fly almost straight downward. Therefore, the molten metal 6 is less likely to adhere to the second piece 22. The direction in which the molten metal 6 flies varies depending on the conditions of the laser 10, but here, the case is shown in which the molten metal 6 flies downward in a substantially straight line.

[0044] Fig. 8(b) shows the die-cast product 1 after the first protruding piece 31 and the second protruding piece 32 have been cut off. The streaks of the laser cutting marks 8 on the second cut surface 42 are similar to those in Fig. 7(b). On the other hand, unlike Fig. 7(b), the streaks of the laser cutting marks 8 on the first cut surface 41 are approximately perpendicular to the first piece 21 and extend from the top to the bottom when viewed from the front. In other words, the streaks of the laser cutting marks 8 on the first cut surface 41 are approximately perpendicular from the surface on the mountain fold side to the surface on the valley fold side when viewed from the front.

[0045] <Cutting method 4> FIG. 9(a) shows an example of a cutting method. The moving direction of the torch 11 is the same as that in FIG. 6(a), and is the right side when cutting the first protruding piece 31, and is the upper side when cutting the second protruding piece 32. That is, when cutting either the first protruding piece 31 or the second protruding piece 32, the moving direction of the torch 11 is the direction approaching the connection part 27. The difference from FIG. 6(a) is the angle of the torch 11. The torch 11 is inclined so as to be tilted forward in the moving direction. Other conditions such as the output and moving speed of the laser 10 are the same as those in FIG. 6(a). By setting the irradiation angle in this way, when cutting the first protruding piece 31, the molten metal 6 can be thrown further left than in FIG. 6(a), and when cutting the second protruding piece 32, the molten metal 6 can be thrown further downward than in FIG. 6(a). Therefore, it is possible to further suppress the adhesion of the molten metal 6 to the first piece 21 and the second piece 22.

[0046] FIG. 9(b) shows the die-cast product 1 after the first protruding piece 31 and the second protruding piece 32 are cut off. The streaks of the laser cutting marks 8 on the first cross section 41 are inclined more to the left and downward when viewed from the front than in FIG. 6(b). That is, the streaks of the laser cutting marks 8 on the first cut surface 41 are inclined more to the left and downward when viewed from the front than in FIG. 6(b). That is, the streaks of the laser cutting marks 8 on the first cut surface 41 are inclined more to the left and downward when viewed from the front than in FIG. 6(b). That is, the streaks of the laser cutting marks 8 on the second cut surface 42 are inclined more to the left and downward when viewed from the front than in FIG. 6(b). That is, the streaks of the laser cutting marks 8 on the second cut surface 42 are inclined more to the left and downward when viewed from the front than in FIG.

[0047] <Cutting method 5> FIG. 10(a) shows an example of a cutting method. The traveling direction of the torch 11 is the same as that in FIG. 6(a), and is the right side when cutting the first protruding piece 31, and is the upper side when cutting the second protruding piece 32. That is, in either case of cutting the first protruding piece 31 or the second protruding piece 32, the traveling direction of the torch 11 is the direction approaching the connection part 27. The difference from FIG. 6(a) is the angle of the torch 11. The torch 11 is inclined so as to be tilted backward in the traveling direction. The laser 10 is irradiated from the rear side to the front side in the traveling direction. Note that other conditions such as the output and moving speed of the laser 10 are the same as those in FIG. 6(a). By setting the irradiation angle in this way, when cutting the first protruding piece 31, the molten metal 6 can be sprayed, for example, downward, and when cutting the second protruding piece 32, the molten metal 6 can be sprayed, for example, toward the left side. In this case, too, it is possible to prevent the molten metal 6 from adhering to the first piece 21 or the second piece 22.

[0048] <Cutting method 6> FIG. 11(a) shows an example of a cutting method. The cutting method of the first protruding piece 31 is the same as that shown in FIG. 6(a). The cutting method of the second protruding piece 32 is different from that shown in FIG. 6(a). That is, the second protruding piece 32 is cut from its upper end 32a to its lower end 32b, in the opposite manner to the case of FIG. 6(a). That is, the torch 11 is moved downward so as to move away from the connecting portion 27. The moving direction of the torch 11 is from the top to the bottom. The torch 11 is perpendicular to the second protruding piece 32. In this way, when the angle of the torch 11 is set perpendicular to the second protruding piece 32 and the torch 11 is moved away from the connecting portion 27, the molten metal 6 is likely to fly to the left and upward. That is, the molten metal 6 is likely to move toward the first piece 21, and the molten metal 6 is likely to adhere to the first piece 21.

[0049] Fig. 11(b) shows the die-cast product 1 after the first protruding piece 31 and the second protruding piece 32 have been cut off. The streaks of the laser cutting marks 8 in the first cross section 41 are the same as those in Fig. 6(b). On the other hand, the streaks of the laser cutting marks 8 in the second cut surface 42 are inclined to the left and upward when viewed from the front, unlike those in Fig. 6(b). In other words, the streaks of the laser cutting marks 8 in the second cut surface 42 are inclined in the direction approaching the first piece 21, from the surface on the mountain fold side to the surface on the valley fold side when viewed from the front.

[0050] <Cutting method 7> FIG. 12(a) shows an example of a cutting method. The cutting method of the second protruding piece 32 is the same as that shown in FIG. 11(a). The cutting method of the first protruding piece 31 is different from that shown in FIG. 11(a). That is, the first protruding piece 31 is cut from its right end 31a toward its left end 31b, in the opposite direction to that shown in FIG. 11(a). That is, the torch 11 is moved away from the connecting portion 27. The angle of the torch 11 is perpendicular to the first protruding piece 31. In this way, in both cases of cutting the first protruding piece 31 and cutting the second protruding piece 32, the moving direction of the torch 11 is a direction away from the connecting portion 27, and the angle of the torch 11 is perpendicular to each of the protruding pieces 31 and 32. When cutting the first protruding piece 31, the molten metal 6 tends to move toward the second piece 22 and adhere to the second piece 22. When the second projecting piece 32 is cut, the molten metal 6 tends to flow toward the first piece 21 and tends to adhere to the first piece 21 .

[0051] Fig. 12(b) shows the die-cast product 1 after the first protruding piece 31 and the second protruding piece 32 have been cut off. The streaks of the laser cutting marks 8 on the second cut surface 42 are similar to those in Fig. 11(b). On the other hand, unlike Fig. 11(b), the streaks of the laser cutting marks 8 on the first cut surface 41 are inclined to the right and downward when viewed from the front. In other words, the streaks of the laser cutting marks 8 on the first cut surface 41 are inclined in the direction approaching the second piece 22, from the surface on the mountain fold side to the surface on the valley fold side when viewed from the front.

[0052] In the above description, the protruding pieces are present on both the first piece 21 and the second piece 22, but the same applies to the case where a protruding piece is present on only one of the first piece 21 and the second piece 22. For example, as shown in Figs. 13 and 14, the same applies to the case where the first protruding piece 31 is provided on the first piece 21 and no protruding piece is provided on the second piece 22. As shown in Fig. 13(a), the torch 11 is set at a right angle to the first protruding piece 31 and moved toward the connection part 27 to cut the first protruding piece 31. In that case, as shown in Fig. 13(b), a line of the laser cutting mark 8 that is inclined downward and to the left when viewed from the front remains on the first cut surface 41.

[0053] Also, as shown in FIG. 14(a), the torch 11 can be moved away from the connecting portion 27 while tilting it backward in the traveling direction to cut the first protruding piece 31. In this case, as shown in FIG. 14(b), a line of the laser cutting mark 8 remains on the first cut surface 41, which is approximately perpendicular to the first piece 21 when viewed from the front. Note that, although the case where a protruding piece is provided only on the first piece 21 is illustrated in FIG. 13 and FIG. 14, the same applies to the case where a protruding piece is provided only on the second piece 22. Also, a protruding piece may be provided on the rear end 21d of the first piece 21 or the rear end 22d of the second piece 22, and these protruding pieces can also be cut by the cutting method described above. For example, the first protruding piece 31 may be provided on the front end 21c of the first piece 21, and the second protruding piece 32 may be provided on the rear end 22d of the second piece 22.

[0054] Next, other specific examples of the die-cast product 1 will be given. Fig. 15 shows a schematic diagram of another example of the die-cast product 1 immediately after casting. Fig. 16 shows the die-cast product 1 after removing the unnecessary portion 3. Fig. 16 shows only the product portion 2, and in Fig. 16, a large number of dots are added to the cut surfaces (first cut surface 41, second cut surface 42, third cut surface 43, fourth cut surface 44, fifth cut surface 45, sixth cut surface 46) where the unnecessary portion 3 has been cut.

[0055] In this embodiment, the product portion 2 has a first piece 21, a second piece 22, a third piece 23, a fourth piece 24, a fifth piece 25, and a sixth piece 26. The first piece 21 to the sixth piece 26 are plate-shaped.

[0056] The first piece 21 and the second piece 22 are the same as those in FIG. 5. The third piece 23 extends downward from the left end 21b of the first piece 21. That is, the second piece 22 and the third piece 23 extend to the same side from the first piece 21. The third piece 23 is bent in a mountain fold relative to the first piece 21 when viewed from above. The second piece 22 and the third piece 23 are both bent to the same side relative to the first piece 21. The second piece 22 and the third piece 23 face each other. In this embodiment, the second piece 22 and the third piece 23 are parallel to each other, but they do not have to be parallel. The second piece 22 and the third piece 23 are perpendicular to the first piece 21, but may be inclined, and the respective bending angles relative to the first piece 21 are arbitrary.

[0057] The right end 21a of the first piece 21 is a connecting end with the second piece 22, and the left end 21b of the first piece 21 is a connecting end with the third piece 23. The upper end 22a of the second piece 22 is a connecting end with the first piece 21, and the lower end 22b of the second piece 22 is a free end. The upper end 23a of the third piece 23 is a connecting end with the first piece 21, and the lower end 23b of the third piece 23 is a free end. The rear end 21d of the first piece 21, the rear end of the second piece 22, and the rear end of the third piece 23 are connecting ends with the fourth piece 24, the fifth piece 25, and the sixth piece 26, respectively.

[0058] The fourth piece 24 extends upward from the rear end 21d of the first piece 21. The fourth piece 24 is bent in a valley fold relative to the first piece 21 when viewed from above. In this embodiment, the fourth piece 24 is bent at a right angle relative to the first piece 21, but the bending angle is arbitrary.

[0059] The fifth piece 25 extends rearward from the right end 24a of the fourth piece 24. The fifth piece 25 is bent in a mountain fold relative to the fourth piece 24 when viewed from the front. In this embodiment, the fifth piece 25 is bent at a right angle relative to the fourth piece 24, but the bending angle is arbitrary. The fifth piece 25 is continuous with the rear side of the second piece 22, and the second piece 22 and the fifth piece 25 are flush with each other.

[0060] The sixth piece 26 extends rearward from the left end 24b of the fourth piece 24. The fifth piece 25 and the sixth piece 26 extend from the fourth piece 24 to the same side. The sixth piece 26 is bent in a mountain fold relative to the fourth piece 24 when viewed from the front. The fifth piece 25 and the sixth piece 26 are both bent to the same side relative to the fourth piece 24. The fifth piece 25 and the sixth piece 26 face each other. In this embodiment, the fifth piece 25 and the sixth piece 26 are parallel to each other, but they do not have to be parallel. The fifth piece 25 and the sixth piece 26 are perpendicular to the fourth piece 24, but may be inclined, and the respective bending angles relative to the fourth piece 24 are arbitrary. The sixth piece 26 is continuous with the rear side of the third piece 23, and the third piece 23 and the sixth piece 26 are flush with each other.

[0061] The right end 24a of the fourth piece 24 is the connecting end with the fifth piece 25, and the left end 24b of the fourth piece 24 is the connecting end with the sixth piece 26. The front end of the fifth piece 25 is the connecting end with the fourth piece 24, and the rear end of the fifth piece 25 is a free end. The front end of the sixth piece 26 is the connecting end with the fourth piece 24, and the rear end of the sixth piece 26 is a free end.

[0062] In this embodiment, the unnecessary portion 3 has a first protruding piece 31, a second protruding piece 32, a third protruding piece 33, a fourth protruding piece 34, a fifth protruding piece 35, and a sixth protruding piece 36. Each protruding piece is plate-shaped. The protruding pieces are, for example, runner portions or the like.

[0063] The first protruding piece 31 and the second protruding piece 32 are the same as those in FIG. 5. The third protruding piece 33 protrudes forward from the front end portion 23c of the third piece 23. The first protruding piece 31, the second protruding piece 32, and the third protruding piece 33 all protrude forward. The first protruding piece 31 is provided on a part of the entire length of the front end portion 21c of the first piece 21, the second protruding piece 32 is provided on a part of the entire length of the front end portion 22c of the second piece 22, and the third protruding piece 33 is provided on a part of the entire length of the front end portion 23c of the third piece 23.

[0064] The fourth protruding piece 34 protrudes upward from the upper end 24c of the fourth piece 24. The fifth protruding piece 35 protrudes upward from the upper end 25c of the fifth piece 25. The sixth protruding piece 36 protrudes upward from the upper end 26c of the sixth piece 26. In this manner, the fourth protruding piece 34, the fifth protruding piece 35, and the sixth protruding piece 36 all protrude upward. The fourth protruding piece 34 is provided on a portion of the entire length of the upper end 24c of the fourth piece 24, the fifth protruding piece 35 is provided on a portion of the entire length of the upper end 25c of the fifth piece 25, and the sixth protruding piece 36 is provided on a portion of the entire length of the upper end 26c of the sixth piece 26.

[0065] The first protruding piece 31 to the sixth protruding piece 36 are cut and removed by the laser 10. Although a case where the third protruding piece 33 is cut from the first protruding piece 31 will be representatively described, the same applies to a case where the sixth protruding piece 36 is cut from the fourth protruding piece 34. The first protruding piece 31 is cut to form a first cut surface 41, the second protruding piece 32 is cut to form a second cut surface 42, the third protruding piece 33 is cut to form a third cut surface 43, the fourth protruding piece 34 is cut to form a fourth cut surface 44, the fifth protruding piece 35 is cut to form a fifth cut surface 45, and the sixth protruding piece 36 is cut to form a sixth cut surface 46.

[0066] 17 to 21 show an example of a cutting method. In addition, in FIG. 17 to FIG. 21, the first piece 21 to the third piece 23 are shown as viewed from the front side, but the fourth piece 24 to the sixth piece 26 are omitted. FIG. 17(a) shows an example of a cutting method. When cutting the first protruding piece 31, the torch 11 is placed on the upper side of the first protruding piece 31, when cutting the second protruding piece 32, the torch 11 is placed on the right side of the second protruding piece 32, and when cutting the third protruding piece 33, the torch 11 is placed on the left side of the third protruding piece 33. That is, the torch 11 is placed on the mountain fold side of each of the first piece 21, the second piece 22, and the third piece 23, and the laser 10 is irradiated toward each protruding piece from the mountain fold side.

[0067] When cutting the first protruding piece 31, the first protruding piece 31 is cut from its left end 31b toward its right end 31a. That is, the first protruding piece 31 is cut while moving the torch 11 to the right. In this case, the torch 11 is tilted so as to tilt toward the left side, which is the rear side in the traveling direction, rather than at a right angle to the first protruding piece 31. That is, the torch 11 is tilted toward the left at a predetermined angle, and the laser 10 is irradiated to the first protruding piece 31 while being inclined obliquely from the left side, which is the rear side in the traveling direction, toward the right side, which is the front side in the traveling direction. In this way, by irradiating the first protruding piece 31 with the laser 10 obliquely from the rear side to the front side in the traveling direction, the molten metal 6 can be thrown substantially straight downward. That is, the molten metal 6 can be thrown in a direction substantially perpendicular to the first piece 21 (substantially normal direction). Therefore, it is possible to suppress the molten metal 6 from adhering to the second piece 22 and the third piece 23.

[0068] When cutting the second protruding piece 32, the second protruding piece 32 is cut from its lower end portion 32b toward its upper end portion 32a. That is, the torch 11 is moved so as to approach the first piece 21. The moving direction of the torch 11 is from the lower side to the upper side. In this case, the torch 11 is perpendicular to the second protruding piece 32 and is set perpendicular to the traveling direction. By setting the traveling direction of the laser 10 to be the direction approaching the connection portion 27 between the first piece 21 and the second piece 22 in this way, the molten metal 6 can be ejected obliquely downward. That is, the molten metal 6 can be ejected in a direction away from the first piece 21, and the adhesion of the molten metal 6 to the first piece 21 can be suppressed.

[0069] The same applies when cutting the third protruding piece 33. The third protruding piece 33 is cut from its lower end portion 33b toward its upper end portion 33a. That is, the torch 11 is moved so as to approach the first piece 21. The moving direction of the torch 11, that is, the traveling direction of the laser 10, is from the lower side to the upper side. Also in this case, the torch 11 is perpendicular to the third protruding piece 33 and is set perpendicular to the traveling direction. By setting the traveling direction of the laser 10 to be the direction approaching the connection portion 27 between the first piece 21 and the third piece 23 in this way, the molten metal 6 can be ejected obliquely downward. That is, the molten metal 6 can be ejected in a direction away from the first piece 21, and the adhesion of the molten metal 6 to the first piece 21 can be suppressed. Incidentally, in this case, after cutting the third protruding piece 33, subsequently, the first protruding piece 31 can be cut in one stroke.

[0070] FIG. 17(b) shows the die-cast product 1 after the first protruding piece 31, the second protruding piece 32, and the third protruding piece 33 are cut. At the front end portion 21c of the first piece 21, a first cut surface 41 is formed by cutting the first protruding piece 31. At the front end portion 22c of the second piece 22, a second cut surface 42 is formed by cutting the second protruding piece 32. At the front end portion 23c of the third piece 23, a third cut surface 43 is formed by cutting the third protruding piece 33.

[0071] The streaks of the laser cut marks 8 on the first cross section 41 are approximately perpendicular to the first piece 21 and extend from the top to the bottom when viewed from the front. That is, the streaks of the laser cut marks 8 on the first cut surface 41 are approximately perpendicular from the mountain fold surface to the valley fold surface when viewed from the front. The streaks of the laser cut marks 8 on the second cut surface 42 are inclined to the left and downward when viewed from the front. That is, the streaks of the laser cut marks 8 on the second cut surface 42 are inclined from the mountain fold surface to the valley fold surface in a direction away from the first piece 21 when viewed from the front. The streaks of the laser cut marks 8 on the third cut surface 43 are inclined to the right and downward when viewed from the front. That is, the streaks of the laser cut marks 8 on the third cut surface 43 are inclined from the mountain fold surface to the valley fold surface in a direction away from the first piece 21 when viewed from the front.

[0072] 18(a) may be used. The cutting of the second protruding piece 32 and the third protruding piece 33 is the same as that in FIG. 17(a). The direction in which the first protruding piece 31 is cut is the opposite to that in FIG. 17(a), and the first protruding piece 31 is cut from its right end 31a to its left end 31b. That is, the traveling direction of the torch 11 is the left side. In this case, the torch 11 is inclined so as to be tilted to the right side, which is the rear side in the traveling direction, with respect to the first protruding piece 31. That is, the torch 11 is tilted to the right at a predetermined angle, and the laser 10 is irradiated to the first protruding piece 31 while being inclined obliquely from the right side, which is the rear side in the traveling direction, to the left side, which is the front side in the traveling direction. Thereby, when the first protruding piece 31 is cut, the molten metal 6 can be thrown substantially straight downward as in FIG. 17(a), and the adhesion of the molten metal 6 to the second piece 22 and the third piece 23 can be suppressed. In this case, after the second projecting piece 32 is cut, the first projecting piece 31 can be cut in a single stroke.

[0073] Fig. 18(b) shows the die-cast product 1 after the first protruding piece 31, the second protruding piece 32, and the third protruding piece 33 have been cut off. The streaks of the laser cutting marks 8 on the first cross section 41, the second cut surface 42, and the third cut surface 43 are similar to those shown in Fig. 17(b).

[0074] 19(a) may be used. The cutting of the first protruding piece 31 is the same as in the case of FIG. 17(a). In FIG. 19(a), when cutting the second protruding piece 32 and the third protruding piece 33, the torch 11 is moved upward as in FIG. 17(a). However, the torch 11 is tilted so as to tilt to the upper side, which is the front side in the traveling direction. By tilting the torch 11 to the front side in the traveling direction in this manner, the laser 10 can be irradiated obliquely from the front side to the rear side in the traveling direction to the second protruding piece 32 and the third protruding piece 33. By irradiating the laser 10 obliquely from the front side to the rear side in the traveling direction to the second protruding piece 32 and the third protruding piece 33, the molten metal 6 can be shot obliquely further downward than in the case shown in FIG. 17, and the adhesion of the molten metal 6 to the first piece 21 can be further suppressed.

[0075] Fig. 19(b) shows the die-cast product 1 after the first protruding piece 31, the second protruding piece 32, and the third protruding piece 33 have been cut off. The streaks of the laser cutting marks 8 on the first cross section 41 are similar to those shown in Fig. 17(b). On the other hand, the streaks of the laser cutting marks 8 on the second cut surface 42 and the third cut surface 43 are inclined further downward than those shown in Fig. 17(b).

[0076] 20(a) may be used. The cutting of the first protruding piece 31 is the same as that in FIG. 17(a). In FIG. 20(a), when cutting the second protruding piece 32 and the third protruding piece 33, the torch 11 is moved downward in the opposite direction to that in FIG. 17(a). That is, when cutting the second protruding piece 32 and the third protruding piece 33, the torch 11 is moved in a direction away from each connection portion 27. Then, the torch 11 is tilted so as to be tilted upward, which is the rear side in the traveling direction. By tilting the torch 11 rearward in the traveling direction in this manner, the laser 10 can be obliquely irradiated to the second protruding piece 32 and the third protruding piece 33 from the rear side to the front side in the traveling direction. By irradiating the laser 10 obliquely to the second protruding piece 32 and the third protruding piece 33 from the rear side to the front side in the traveling direction, the molten metal 6 can be thrown approximately horizontally so as not to approach the first piece 21. That is, the molten metal 6 can be thrown in a direction approximately perpendicular to the second piece 22 and the third piece 23. This makes it possible to suppress adhesion of the molten metal 6 to the first piece 21 .

[0077] FIG. 20(b) shows the die-cast product 1 after the first protruding piece 31, the second protruding piece 32, and the third protruding piece 33 are cut off. The streaks of the laser cutting marks 8 in the first cross section 41 are similar to those shown in FIG. 17(b). On the other hand, the streaks of the laser cutting marks 8 in the second cut surface 42 and the third cut surface 43 are approximately perpendicular to the second piece 22 and the third piece 23, respectively. That is, the streaks of the laser cutting marks 8 in the second cut surface 42 and the third cut surface 43 extend approximately perpendicularly from the mountain fold surface to the valley fold surface when viewed from the front. Thus, in the case of FIG. 20(b), all the streaks of the laser cutting marks 8 extend approximately perpendicularly from the mountain fold surface to the valley fold surface when viewed from the front.

[0078] 21(a) may be used. The cutting of the first protruding piece 31 is the same as in FIG. 17(a). The moving direction of the torch 11 when cutting the second protruding piece 32 and the third protruding piece 33 is also the same as in FIG. 17(a). What is different from FIG. 17(a) is the angle of the torch 11 when cutting the second protruding piece 32 and the third protruding piece 33. That is, when cutting the second protruding piece 32 and the third protruding piece 33, the torch 11 is tilted so as to be tilted downward, which is the rear side in the traveling direction. By tilting the torch 11 rearward in the traveling direction in this way, the laser 10 can be irradiated obliquely from the rear side to the front side in the traveling direction to the second protruding piece 32 and the third protruding piece 33. By irradiating the laser 10 obliquely from the rear side to the front side in the traveling direction to the second protruding piece 32 and the third protruding piece 33, the molten metal 6 can be scattered approximately horizontally so as not to approach the first piece 21. In other words, the molten metal 6 can be splashed in a direction substantially perpendicular to the second piece 22 and the third piece 23. This makes it possible to prevent the molten metal 6 from adhering to the first piece 21.

[0079] Fig. 21(b) shows the die-cast product 1 after the first protruding piece 31, the second protruding piece 32, and the third protruding piece 33 have been cut off. The streaks of the laser cutting marks 8 are similar to those shown in Fig. 20(b).

[0080] In addition, in Fig. 15, the first piece 21, the second piece 22, and the third piece 23 are all provided with protruding pieces, but for example, only one piece or only two pieces of these three pieces may be provided with protruding pieces. The same applies to the fourth piece 24, the fifth piece 25, and the sixth piece 26. Also, the fourth piece 24 is bent in a valley fold (a shape bent upward) relative to the first piece 21 when viewed from above, but conversely, the fourth piece 24 may be bent in a mountain fold (a shape bent downward) relative to the first piece 21 when viewed from above. Also, the fourth piece 24 to the sixth piece 26 may be omitted. [Explanation of symbols]

[0081] 1. Die-cast products 2 Product Department 3. Don't 4 protruding piece 4a Side 1 4b Side 2 4c Right end 4d Left end 5 molten part 6 molten metal 7 Cut surface 8 レーザ cutting marks 10 レーザ 11 トーチ 21 First Film 21a Right end (one end in the first direction) 21b Left end (other end in the first direction) 21c front end (one end in the second direction) 21d rear end (other end in the second direction) 22 The second piece 22a Upper end 22b Lower end 22c Front end 23 The third piece 23a Upper end 23b Lower end 23c Front end 24 The fourth piece 24a Right end 24b Left end 24c Upper end 25 The fifth piece 25c Upper end 26 The Sixth Piece 26c Upper end 27 Jiebu 31 First protruding piece 31a Right end 31b Left end 32 Second protruding piece 32a Upper end 32b Lower end 33 Third protruding piece 33a Upper end 33b Lower end 34 Fourth protruding piece 35 Fifth protrusion 36 Sixth protruding piece 41 First section 42 Second section 43 Third section 44 Fourth section 45 Fifth section 46 Sixth section 101 First Direction 102 Second Direction 103 The Third Direction

Claims

1. A method for cutting off an unnecessary portion from a product portion of a cast die-cast product, comprising the steps of: The product portion has a first piece and a second piece that is bent in a mountain fold relative to the first piece and extends from one end of the first piece in a first direction, the unnecessary portion has a protruding piece protruding in the second direction at least at one end of the first piece in a second direction perpendicular to the first direction and at least one end of the second piece in the second direction, A cutting step is provided in which a laser is irradiated from the mountain fold side to cut off the unnecessary portion, The cutting process is a method for cutting unnecessary portions of a die-cast product, the method including a step of advancing a laser in a direction away from the connection between the first piece and the second piece and irradiating the laser diagonally from the rear side to the front side in the direction of advancement to cut off the protruding piece.

2. A method for cutting off an unnecessary portion from a product portion of a cast die-cast product, comprising the steps of: The product portion has a first piece, a second piece bent in a mountain fold relative to the first piece and extending from one end of the first piece in the first direction, and a third piece bent in a mountain fold relative to the first piece and extending from the other end of the first piece in the first direction, the unnecessary portion has a first protruding piece protruding in the second direction from one end of the first piece in a second direction perpendicular to the first direction, A cutting step is provided in which a laser is irradiated from the mountain fold side to cut off the unnecessary portion, The cutting step is a method for cutting off an unnecessary portion of a die-cast product, the method including a step of irradiating a laser obliquely from the rear side to the front side in the traveling direction to cut off the first protruding piece.

3. the unnecessary portion has a second protruding piece protruding in the second direction from one end of the second piece in the second direction, 3. The method for cutting off an unnecessary portion of a die-cast product according to claim 2, wherein the cutting step includes a step of advancing a laser in a direction approaching the connection portion between the first piece and the second piece to cut off the second protruding piece.

4. the unnecessary portion has a second protruding piece protruding in the second direction from one end of the second piece in the second direction, A method for cutting unnecessary portions of a die-cast product as described in claim 2, wherein the cutting process includes a step of advancing a laser in a direction away from the connection portion between the first piece and the second piece and irradiating the laser obliquely from the rear side to the front side in the direction of advancement to cut the second protruding piece.

5. A die-cast product from which unnecessary parts have been cut off, A first piece and a second piece extending from one end of the first piece in a first direction while being bent in a mountain fold relative to the first piece, A cut surface having a streak-like laser cut mark is provided on both one end of the first piece in a second direction perpendicular to the first direction and one end of the second piece in the second direction, The laser cut mark of the first piece is a line inclined in a direction away from the second piece from the mountain fold surface to the valley fold surface, A die-cast product in which the laser cutting marks on the second piece are lines that are inclined in a direction away from the first piece from the mountain fold surface to the valley fold surface.

6. A die-cast product from which unnecessary parts have been cut off, A first piece and a second piece extending from one end of the first piece in a first direction while being bent in a mountain fold relative to the first piece, a cut surface having a streak-like laser cut mark is provided on both one end of the first piece in a second direction perpendicular to the first direction and one end of the second piece in the second direction; The laser cut mark of the first piece is a line inclined in a direction away from the second piece from the mountain fold surface to the valley fold surface, A die-cast product in which the laser cutting marks on the second piece are approximately vertical lines extending from the mountain fold surface to the valley fold surface.

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