Method for cutting unnecessary part from die-cast product and die-cast product
Patent Information
- Application Number
- JP2025041231
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-10-03
AI Technical Summary
Existing methods for cutting unnecessary parts from die-cast products, such as runner parts, are often difficult or impossible due to the shape of the product, and can result in product deformation or defects from excessive force or molten metal adhesion.
A method using a laser to cut unnecessary parts from die-cast products, where the laser is irradiated from the mountain fold side to melt and cut the protruding pieces, and the laser is advanced in a direction approaching the connection part to minimize molten metal adhesion and deformation.
This method allows for easy and non-contact cutting of unnecessary parts without deforming the product, while reducing the risk of molten metal adhesion and subsequent product defects.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a method for cutting unnecessary parts from a die-cast product after casting, and a die-cast product from which unnecessary parts have been cut.
Background Art
[0002] In a cast die-cast product, there are unnecessary parts such as a runner part. In the following Patent Documents 1 to 3, unnecessary parts such as a runner part are trimmed by a press machine. 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
Patent Document 2
Patent Document 3
Summary of the Invention
Problems to be Solved by the Invention
[0004] An object of the present invention is to enable easy cutting of unnecessary parts from a die-cast product.
Means for Solving the Problems
[0005] The method for cutting unnecessary parts of a die-cast product according to the present invention is a method for cutting unnecessary parts from the product part of a cast die-cast product. The product part has a first piece and a second piece that is bent in a mountain fold with respect to the first piece and extends from one end of the first piece in the first direction. The unnecessary part has a protruding piece that protrudes in the second direction at at least one of one end of the first piece in the second direction orthogonal to the first direction and one end of the second piece in the second direction. The method includes a cutting step of irradiating the unnecessary part with a laser from the mountain fold side to cut it. The cutting step includes a step of advancing the laser in a direction approaching the connection part of the first piece and the second piece to cut the protruding piece.
[0006] In the cast die-cast product, the second piece is bent with respect to the first piece. A protruding piece as an unnecessary part is provided on the first piece or the second piece. The protruding piece is, for example, a runner part or the like. Since the second piece is bent with respect 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. Also, by irradiating the laser from the mountain fold side instead of the valley fold side, the laser can be easily irradiated onto the protruding piece. And the protruding piece can be cut non-contact by the laser. Therefore, an excessive force does not act on the product part, and there is no risk of the product part being deformed like in pressing, and the protruding piece can be easily separated and removed from the product part.
[0007] On the other hand, when the protruding piece is irradiated with a laser, the cutting portion of the protruding piece melts, and the molten metal (spatter) scatters to the side opposite to the laser irradiation side. Since the first piece and the second piece are bent with respect to each other, there is a risk that the molten metal adheres to the valley fold side surface 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 adheres to the second piece, and when cutting the protruding piece of the second piece, there is a risk that the molten metal adheres to the first piece. If the molten metal adheres to the first piece or the second piece, it may cause product defects.
[0008] In the above method, when cutting the protruding piece with a laser, instead of advancing the laser in a direction away from the connection part between the first piece and the second piece, the laser is advanced in a direction approaching the connection part. If the laser is advanced in a direction away from the connection part between the first piece and the second piece, the molten metal is likely to fly toward the connection part side which is on the rear side in the advancing direction of the laser. That is, when cutting the protruding piece of the first piece, the molten metal is likely to fly toward the second piece, and when cutting the protruding piece of the second piece, the molten metal is likely to fly toward the first piece. On the other hand, when the laser is advanced in a direction approaching the connection part, the molten metal is likely to fly to the side opposite to the connection part and is less likely to fly toward the first piece or the second piece. Therefore, it is less likely for the molten metal to adhere to the first piece or the second piece. Although the direction in which the molten metal flies varies depending on various conditions such as the output of the laser, irradiation time, moving speed, irradiation angle, etc., compared with the case where the laser is advanced in a direction away from the connection part, by advancing the laser in a direction approaching the connection part, it becomes less likely for the molten metal to fly toward the connection part side, and it is possible to suppress the adhesion of the molten metal to the first piece or the second piece.
[0009] Further, the method for cutting an unnecessary part of a die-cast product according to the present invention is a method for cutting an unnecessary part from a product part of a cast die-cast product. The product part has a first piece and a second piece that is bent in a mountain-fold manner with respect to the first piece and extends from one end of the first piece in the first direction. The unnecessary part has a protruding piece that protrudes in the second direction at at least one of one end of the first piece in the second direction orthogonal to the first direction and one end of the second piece in the second direction. The method includes a cutting step of irradiating from the mountain-fold side with a laser to cut the unnecessary part. The cutting step includes a step of advancing the laser in a direction away from the connection part between the first piece and the second piece and obliquely irradiating the protruding piece by advancing the laser obliquely from the rear side to the front side in the advancing direction.
[0010] According to this method, when cutting the protruding piece with a laser, the laser is made to travel in a direction away from the connecting part. As described above, when the traveling direction of the laser is away from the connecting part, the molten metal is likely to jump toward the connecting part side. In this case, instead of irradiating the protruding piece perpendicularly with the laser, the laser is irradiated at an angle. That is, the laser is obliquely irradiated on the protruding piece from the rear side to the front side in the traveling direction. When the laser is irradiated at an angle in this way, at the end on the cutting start side of the protruding piece, it is possible to melt the surface on the side opposite to the laser irradiation side (valley-fold side) earlier than the surface on the laser irradiation side (mountain-fold side). And then, the melted part can be expanded to the surface on the laser irradiation side. Therefore, compared with the case where the irradiation angle of the laser is perpendicular, the molten metal is less likely to jump to the rear side in the traveling direction of the laser, and it is less likely for the molten metal to adhere to the first piece or the second piece.
[0011] Moreover, the method for cutting an unnecessary part of a die-cast product according to the present invention is a method for cutting an unnecessary part from a product part of a cast die-cast product. The product part includes a first piece, a second piece that is bent in a mountain-fold manner with respect to the first piece and extends from one end of the first piece in a first direction, and a third piece that is bent in a mountain-fold manner with respect to the first piece and extends from the other end of the first piece in the first direction. The unnecessary part has a first protruding piece that protrudes in a second direction from one end of the first piece in a second direction orthogonal to the first direction. The method includes a cutting step of irradiating the unnecessary part with a laser from the mountain-fold side to cut it. The cutting step includes a step of obliquely irradiating the first protruding piece with the laser from the rear side to the front side in the traveling direction to cut the first protruding piece.
[0012] According to this method, when cutting the first protruding piece, the laser is obliquely irradiated on the first protruding piece from the rear side to the front side in the traveling direction. As a result, the molten metal is less likely to jump toward the second piece or the third piece, and it is less likely for the molten metal to adhere to the second piece or the third piece.
[0013] In particular, the unnecessary part has a second protruding piece that protrudes in the second direction from one end in the second direction of the second piece, and the cutting process preferably includes a process of advancing a laser in a direction approaching the connection part between the first piece and the second piece to cut the second protruding piece. Thereby, when cutting the second protruding piece, it becomes difficult for the molten metal to go toward the first piece and difficult to adhere to the first piece.
[0014] Also, the unnecessary part has a second protruding piece that protrudes in the second direction from one end in the second direction of the second piece, and the cutting process preferably includes a process of advancing the laser in a direction away from the connection part between the first piece and the second piece and obliquely irradiating the laser from the rear side to the front side in the advancing direction to cut the second protruding piece. Thereby, when cutting the second protruding piece, it becomes difficult for the molten metal to go toward the first piece and difficult to adhere to the first piece.
[0015] Moreover, the die-cast product according to the present invention is a die-cast product in which an unnecessary part is cut, and includes a first piece and a second piece that is bent in a mountain fold with respect to the first piece and extends from one end in the first direction of the first piece. A cut surface having a streak-like laser cutting mark is provided on at least one of one end in the second direction orthogonal to the first direction of the first piece and one end in the second direction of the second piece. The laser cutting mark is a streak inclined in a direction away from the other piece from the surface on the mountain fold side toward the surface on the valley fold side, or a streak substantially perpendicular from the surface on the mountain fold side toward the surface on the valley fold side.
Effects of the Invention
[0016] As described above, by melting and cutting the unnecessary part non-contact by a laser, the restrictions on the shape of the die-cast product are reduced, and the unnecessary part can be easily cut without deforming the product part. And, by the advancing direction of the laser or the inclination with respect to the advancing direction of the laser, the adhesion of the molten metal to the product part can be suppressed, and the occurrence of product defects can be suppressed.
Brief Description of the Drawings
[0017]
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Embodiments for Carrying Out the Invention
[0018] Hereinafter, a method for cutting unnecessary parts in a die-cast product according to an embodiment of the present invention and the die-cast product with the unnecessary parts cut will be described with reference to the drawings. The die-cast product 1 is composed of a product part 2 and an unnecessary part 3, and the cutting method is to cut the unnecessary part 3. First, the basic principle of the cutting method will be explained.
[0019] Figs. 1 to 4 conceptually show the cutting method. The cutting method is to irradiate the protruding piece 4 as the unnecessary part 3 with the laser 10 and cut the protruding piece 4 with the laser 10. Figs. 1 to 4 are views of the protruding piece 4 seen in the protruding direction from the tip side in the protruding direction. The protruding piece 4 is plate-shaped with the first surface 4a and the second surface 4b as the plate surfaces. The laser 10 irradiates 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 anti-laser irradiation side. In Fig. 1 etc., a torch 11 (nozzle) for irradiating the laser 10 is shown. The laser 10 is irradiated from the tip of the torch 11. Incidentally, air is supplied inside the torch 11. Therefore, air is jetted from the tip of the torch 11 together with the laser 10.
[0020] In FIG. 1, the left end portion 4d (one end portion in the advancing direction) of the protruding piece 4 is irradiated with the laser 10. The arrow A shown in FIG. 1 indicates the advancing direction (scanning direction) of the laser 10. In FIG. 1, the laser 10 advances from the left side to the right side toward the paper surface. The laser 10 is irradiated onto the protruding piece 4 from the first surface 4a side of the protruding piece 4. The torch 11 is perpendicular to the advancing direction. The laser 10 is irradiated perpendicularly toward the first surface 4a of the protruding piece 4. As shown in FIG. 1(a), when the laser 10 is irradiated perpendicularly to the first surface 4a at the left end portion 4d of the protruding piece 4, the left end portion 4d of the protruding piece 4 begins to melt from the first surface 4a side.
[0021] Then, as shown in FIG. 1(b), the melting of the left end portion 4d of the protruding piece 4 proceeds from the first surface 4a side to the second surface 4b side, and as the torch 11 is moved toward the right side, the melted portion 5 of the protruding piece 4 expands toward the right side. Incidentally, in the figure, a large number of dots are shown in the melted portion 5. 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) will fly obliquely to the left as shown in FIG. 1(b). That is, the molten metal 6 will fly obliquely from the first surface 4a side to the second surface 4b side and toward the rear side with respect to the advancing direction of the laser 10. Incidentally, 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, etc.
[0022] FIG. 1(c) shows the cut surface 7 after the protruding piece 4 is cut. On the cut surface 7, traces of the melting of the protruding piece 4 due to the irradiation and scanning of the laser 10 remain as laser cutting marks 8. The laser cutting marks 8 are streak-like, and the direction of the streaks is close to the direction in which the molten metal 6 travels. In this example, as described above, the molten metal 6 travels obliquely to the left and downward. Therefore, the streaks of the laser cutting marks 8 are inclined to the left and downward when viewed from the front. That is, the streaks of the laser cutting marks 8 are inclined from the first surface 4a to the second surface 4b and to the rear side of the advancing direction of the laser 10.
[0023] FIG. 2 shows a case where the torch 11 is moved from the right end portion 4c of the protruding piece 4 toward the left side to cut the protruding piece 4, contrary to FIG. 1. Similarly in this case, first, melting starts from the first surface 4a side of the right end portion 4c as shown in FIG. 2(a), and then the melted portion 5 gradually expands toward the second surface 4b side. At the same time, as shown in FIG. 2(b), as the torch 11 advances to the left side, on the first surface 4a side, the melted portion 5 expands to the left side earlier than the second surface 4b side, while the second surface 4b side melts later and with a delay. Therefore, the molten metal 6 will fly diagonally to the right as shown in FIG. 2(b). That is, the molten metal 6 will fly obliquely from the first surface 4a side to the second surface 4b side and toward the rear side with respect to the advancing direction of the laser 10.
[0024] FIG. 2(c) shows the cut surface 7 after the protruding piece 4 is cut. In this example, as described above, the molten metal 6 goes diagonally to the right. Therefore, the streak of the laser cutting mark 8 is inclined to the right side and the lower side when viewed from the front. That is, the streak of the laser cutting mark 8 is inclined from the first surface 4a toward the second surface 4b and toward the rear side of the advancing direction of the laser 10.
[0025] On the other hand, the laser 10 can also be irradiated from a direction inclined with respect to the protruding piece 4 rather than perpendicularly. In that case, the molten metal 6 can be made to fly in a direction different from the case where the laser 10 is irradiated perpendicularly to the protruding piece 4.
[0026] In FIG. 3, the torch 11 is tilted so as to fall backward from a state perpendicular to 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 in 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 portion 4d (left side surface) of the protruding piece 4. More specifically, the laser 10 is first irradiated to the second surface 4b side rather than the first surface 4a side of the left end portion 4d of the protruding piece 4. Therefore, the second surface 4b side of the left end portion 4d of the protruding piece 4 starts to melt earlier than the first surface 4a side. Then, as shown in FIG. 3(b), as the laser 10 moves toward the right side, the molten portion 5 expands from the second surface 4b side to the first surface 4a side of the left end portion 4d of the protruding piece 4. As a result, the molten metal 6 is less likely to fly backward in the traveling direction of the laser 10 compared to the case where the laser 10 is irradiated perpendicularly. In FIG. 3(b), as an example for easy understanding, a state where the molten metal 6 flies substantially straight from the first surface 4a side to the second surface 4b side is shown, but the direction in 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.
[0027] FIG. 3(c) shows the cut surface 7 after the protruding piece 4 is cut. In this example, as an example for easy understanding, a case where the molten metal 6 travels substantially straight from the first surface 4a side to the second surface 4b side is shown. In this case, the streak of the laser cut mark 8 is substantially perpendicular when viewed from the front. That is, the streak of the laser cut mark 8 is a streak in a substantially perpendicular direction from the first surface 4a to the second surface 4b.
[0028] In Figure 4, contrary to Figure 3, the torch 11 is inclined so as to fall forward in the traveling direction from a state perpendicular to the traveling direction. The traveling direction of the laser 10 is from the left side to the right side as in Figure 3. The laser 10 is irradiated obliquely from the front side to the rear side in the traveling direction. As shown in Figure 4(a), the laser 10 is irradiated onto the first surface 4a of the left end portion 4d of the protruding piece 4. Therefore, the first surface 4a side of the left end portion 4d of the protruding piece 4 starts to melt earlier than 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 portion 4d of the protruding piece 4 progresses from the first surface 4a side to the second surface 4b side. That is, the first surface 4a side of the protruding piece 4 melts significantly ahead of the second surface 4b side, and the second surface 4b side melts considerably later. Therefore, the molten metal 6 flies obliquely to the left as shown in Figure 4(b). This inclination angle to the oblique left becomes larger than when shown in Figure 1(b) when the conditions such as the output of the laser 10 are the same as in the case of Figure 1, and it flies with a larger inclination to the oblique left than in Figure 1(b).
[0029] Figure 4(c) shows the cut surface 7 after the protruding piece 4 is cut. In this example, as described above, the molten metal 6 goes further to the left than in the case of Figure 1(b). The streak of the laser cut mark 8 is inclined more greatly to the left side and the lower side than in Figure 1(c) when viewed from the front. The streak of the laser cut mark 8 is inclined greatly to the rear side in the traveling direction of the laser 10 from the first surface 4a to the second surface 4b.
[0030] Next, a specific example of the die-cast product 1 will be given for further explanation. Figure 5(a) schematically shows an example of the die-cast product 1 immediately after casting. Also, Figure 5(b) shows the state where the unnecessary portion 3 is removed from the die-cast product 1, that is, only the product portion 2. Incidentally, in Figure 5(b), a large number of dots are attached to the cut surfaces (the first cut surface 41 and the second cut surface 42) where the unnecessary portion 3 is cut.
[0031] The die-cast product 1 immediately after casting has an unnecessary part 3 in addition to the product part 2. The shape of the product part 2 is arbitrary, but in this embodiment, the product part 2 has a first piece 21 and a second piece 22. The first piece 21 and the second piece 22 are plate-shaped.
[0032] Let the two longitudinal and transverse directions of the first piece 21 be the first direction 101 and the second direction 102 respectively. The first direction 101 and the second direction 102 are perpendicular to each other. Let the plate thickness direction of the first piece 21 be the 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 the left-right direction, and the left and right directions are defined based on the case where the product part 2 is viewed from the first end side in 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. Also, the second direction 102 is the front-rear direction, and the first end side of the second direction 102 is 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. Further, the third direction 103 is the up-down direction, and the direction in which the second piece 22 extends from the first piece 21 is the lower side. The first end of the third direction 103 is the upper end, and the second end of the third direction 103 is the lower end.
[0033] The first piece 21 extends horizontally, and the second piece 22 extends downward from the right end 21a of the first piece 21. The second piece 22 is bent in a mountain fold when viewed from above with respect to the first piece 21. In this embodiment, the second piece 22 is bent at a right angle with respect to the first piece 21, but the bending angle is arbitrary. The right end 21a of the first piece 21 is the connection end with the second piece 22, and the left end 21b of the first piece 21 is the free end. Also, the upper end 22a of the second piece 22 is the connection end with the first piece 21, and the lower end 22b of the second piece 22 is the free end.
[0034] The shape of the unnecessary part 3 is arbitrary, but in this embodiment, the unnecessary part 3 has a first protruding piece 31 and a second protruding piece 32. Each protruding piece 31, 32 is plate-shaped. The protruding piece is, for example, a runner part or the like.
[0035] The first protruding piece 31 protrudes forward from the front end portion 21c of the first piece 21. The second protruding piece 32 protrudes forward from the front end portion 22c of the second piece 22. Thus, 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 part of the entire length of the front end portion 21c of the first piece 21, and 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.
[0036] Next, a method for cutting these first protruding piece 31 and second protruding piece 32 will be described. FIGS. 6 to 11 show various cutting methods. In FIGS. 6 to 11, the states of the first piece 21 and the second piece 22 as viewed from the front side are shown.
[0037] <Cutting Method No. 1> FIG. 6(a) shows an example of the cutting method. When cutting the first protruding piece 31, the torch 11 is installed above the first protruding piece 31. When cutting the second protruding piece 32, the torch 11 is installed on the right side of the second protruding piece 32. Thus, the torch 11 is installed on the mountain-fold side of each of the first piece 21 and the second piece 22, and the laser 10 is irradiated from the mountain-fold side.
[0038] When cutting the first protruding piece 31, the first protruding piece 31 is cut from its left end portion 31b toward the right end portion 31a. That is, while moving the torch 11 to the right toward the connection portion 27 between the first piece 21 and the second piece 22, the first protruding piece 31 is cut. The torch 11 is perpendicular to the first protruding piece 31 and is set perpendicular to the traveling direction. By setting the traveling direction of the laser 10 (the moving direction of the torch 11) to be the direction approaching the connection portion 27 in this way, the molten metal 6 can be blown obliquely to the left. That is, the molten metal 6 can be blown in a direction away from the second piece 22, and it is possible to suppress the molten metal 6 from adhering to the second piece 22. Note that the angle at which the molten metal 6 flies 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 portion 32b toward its upper end portion 32a. That is, the torch 11 is moved upward so as to approach the first piece 21, that is, so as to approach the connecting portion 27. The moving direction of the torch 11 is from the lower side to the upper side. 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 in this way to be the direction approaching the connecting portion 27, the molten metal 6 can be blown obliquely downward. That is, the molten metal 6 can be blown in a direction away from the first piece 21, and it is possible to suppress the molten metal 6 from adhering to the first piece 21. Also in this case, the angle at which the molten metal 6 flies varies depending on various conditions of the laser 10. Incidentally, the cutting order of the first protruding piece 31 and the second protruding piece 32 may be either first.
[0040] Fig. 6(b) shows the die-cast product 1 after the first protruding piece 31 and the second protruding piece 32 are cut. A first cut surface 41 formed by cutting the first protruding piece 31 is provided at the front end portion 21c of the first piece 21. A second cut surface 42 formed by cutting the second protruding piece 32 is provided at the front end portion 22c of the second piece 22. The streaks of the laser cut marks 8 on the first cut surface 41 are inclined to the left 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 laser irradiation side surface) toward the valley-fold side surface (the anti-laser irradiation side surface) when viewed from the front. Also, 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 in a direction away from the first piece 21 from the mountain-fold side surface toward the valley-fold side surface when viewed from the front. Incidentally, the inclination angle of the streaks varies depending on various conditions of the laser 10.
[0041] <Cutting Method Part 2> Fig. 7(a) shows an example of the 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 in Fig. 6(a). That is, contrary to the case of Fig. 6(a), the second protruding piece 32 is cut from its upper end 32a toward its lower end 32b. That is, the torch 11 is moved downward so as to be away from the first piece 21, that is, away from the connecting portion 27. The moving direction of the torch 11 is from the upper side to the lower side. The torch 11 is not perpendicular to the second protruding piece 32, but is inclined so as to fall on the upper side which is the rear side in the advancing direction. That is, the torch 11 is tilted upward by a predetermined angle, and the laser 10 is obliquely inclined from the upper side which is the rear side in the advancing direction toward the lower side which is the front side in the advancing direction and irradiates the second protruding piece 32. Thereby, the molten metal 6 can be flown straight substantially at a right angle to the second piece 22, that is, toward the left side. Therefore, it becomes difficult for the molten metal 6 to adhere to the first piece 21. Note that the direction in which the molten metal 6 flies varies depending on the conditions of the laser 10, but here, the case where it flies straight substantially toward the left side is shown. Further, for example, after cutting the first protruding piece 31, the second protruding piece 32 can be continuously cut in one stroke.
[0042] Fig. 7(b) shows the die-cast product 1 after the first protruding piece 31 and the second protruding piece 32 are cut. The grain of the laser cutting mark 8 on the first cutting surface 41 is the same as that in Fig. 6(b). On the other hand, the grain of the laser cutting mark 8 on the second cutting surface 42 is different from that in Fig. 6(b). When viewed from the front, it is substantially perpendicular to the second piece 22 and extends from the right side to the left side. That is, the grain of the laser cutting mark 8 on the second cutting surface 42 is a grain substantially perpendicular from the mountain-folded side surface to the valley-folded side surface when viewed from the front.
[0043] <Cutting Method Part 3> Fig. 8(a) shows an example of the 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 in Fig. 7(a). That is, contrary to the case of Fig. 7(a), the first protruding piece 31 is cut from its right end 31a toward the left end 31b. That is, the torch 11 is moved to the left so as to be away from the second piece 22, that is, away from the connecting portion 27. The moving direction of the torch 11 is from the right side to the left side. The torch 11 is not perpendicular to the first protruding piece 31, but is tilted so as to fall to the right side which is the rear side in the advancing direction. That is, the torch 11 is tilted to the right by a predetermined angle, and the laser 10 is obliquely tilted from the right side which is the rear side in the advancing direction toward the left side which is the front side in the advancing direction and irradiates the first protruding piece 31. Thereby, the molten metal 6 can be flown straight downward substantially. Therefore, it becomes difficult for the molten metal 6 to adhere to the second piece 22. Note that the direction in which the molten metal 6 flies varies depending on the conditions of the laser 10, but here the case where it flies straight downward substantially is shown.
[0044] Fig. 8(b) shows the die-cast product 1 after the first protruding piece 31 and the second protruding piece 32 are cut. The streaks of the laser cutting marks 8 on the second cutting surface 42 are the same as those in Fig. 7(b). On the other hand, the streaks of the laser cutting marks 8 on the first cutting surface 41 are different from those in Fig. 7(b). When viewed from the front, they are substantially perpendicular to the first piece 21 and extend from the upper side to the lower side. That is, the streaks of the laser cutting marks 8 on the first cutting surface 41 are streaks that are substantially perpendicular from the mountain-folded side surface to the valley-folded side surface when viewed from the front.
[0045] <Cutting Method No. 4> Fig. 9(a) shows an example of the cutting method. The advancing direction of the torch 11 is the same as that in the case of Fig. 6(a). When cutting the first protruding piece 31, it is to the right, and when cutting the second protruding piece 32, it is upward. That is, in either case of cutting the first protruding piece 31 or the second protruding piece 32, the advancing direction of the torch 11 is the direction approaching the connecting portion 27. What is different from Fig. 6(a) is the angle of the torch 11. The torch 11 is inclined so as to fall forward in the advancing direction. Incidentally, other conditions such as the output of the laser 10 and the moving speed are the same as those in Fig. 6(a). When setting the irradiation angle in this way, when cutting the first protruding piece 31, the molten metal 6 can be ejected more to the left than in Fig. 6(a), and when cutting the second protruding piece 32, the molten metal 6 can be ejected more 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. The streaks of the laser cutting marks 8 on the first cutting surface 41 are inclined more greatly to the left and downward than in the case of Fig. 6(b) when viewed from the front. That is, the streaks of the laser cutting marks 8 on the first cutting surface 41 are inclined greatly in the direction away from 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. Also, the streaks of the laser cutting marks 8 on the second cutting surface 42 are inclined more greatly to the left and downward than in the case of Fig. 6(b) when viewed from the front. That is, the streaks of the laser cutting marks 8 on the second cutting surface 42 are inclined greatly in the direction away from 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.
[0047] <Cutting method No. 5> FIG. 10(a) shows an example of the cutting method. The traveling direction of the torch 11 is the same as that in the case of FIG. 6(a). When cutting the first protruding piece 31, it is on the right side, and when cutting the second protruding piece 32, it is on the upper side. 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 connecting portion 27. What is different 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. Incidentally, other conditions such as the output and moving speed of the laser 10 are the same as those in FIG. 6(a). When the irradiation angle is set in this way, when cutting the first protruding piece 31, the molten metal 6 can be ejected, for example, downward, and when cutting the second protruding piece 32, it can be ejected, for example, to the left side. Also in this case, it is possible to suppress the adhesion of the molten metal 6 to the first piece 21 and the second piece 22.
[0048] <Cutting Method No. 6> FIG. 11(a) shows an example of the 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 in FIG. 6(a). That is, contrary to the case of FIG. 6(a), the second protruding piece 32 is cut from its upper end portion 32a toward its lower end portion 32b. That is, the torch 11 is moved downward so as to be away from the connecting portion 27. The moving direction of the torch 11 is from the upper side to the lower side. 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 toward the left side and the upper side. 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 are cut. The grain of the laser cutting mark 8 on the first cutting surface 41 is the same as that in Fig. 6(b). On the other hand, the grain of the laser cutting mark 8 on the second cutting surface 42 is different from that in Fig. 6(b). When viewed from the front, it is inclined to the left and upper side. That is, the grain of the laser cutting mark 8 on the second cutting surface 42 is inclined in the direction approaching the first piece 21 from the mountain-fold side surface to the valley-fold side surface when viewed from the front.
[0050] <Cutting Method No. 7> Fig. 12(a) shows an example of the 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 in Fig. 11(a). That is, contrary to the case of Fig. 11(a), the first protruding piece 31 is cut from its right end 31a toward the left end 31b. That is, the torch 11 is moved away from the connecting portion 27. Also, the angle of the torch 11 is perpendicular to the first protruding piece 31. In this way, in both the case of cutting the first protruding piece 31 and the case of cutting the second protruding piece 32, the advancing direction of the torch 11 is away from the connecting portion 27, and the angle of the torch 11 is perpendicular to each of the protruding pieces 31, 32. When cutting the first protruding piece 31, the molten metal 6 tends to move toward the second piece 22 and easily adheres to the second piece 22. When cutting the second protruding piece 32, the molten metal 6 tends to move toward the first piece 21 and easily adheres 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 are cut. The grain of the laser cutting mark 8 on the second cutting surface 42 is the same as that in Fig. 11(b). On the other hand, the grain of the laser cutting mark 8 on the first cutting surface 41 is different from that in Fig. 11(b). When viewed from the front, it is inclined to the right and lower side. That is, the grain of the laser cutting mark 8 on the first cutting surface 41 is inclined in the direction approaching the second piece 22 from the mountain-fold side surface to the valley-fold side surface when viewed from the front.
[0052] In the above description, protruding pieces existed on both the first piece 21 and the second piece 22. However, the same applies even when protruding pieces exist only on one of the first piece 21 and the second piece 22. For example, as shown in FIGS. 13 and 14, even when 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 can be set at a right angle to the first protruding piece 31 and moved toward the connecting portion 27 to cut the first protruding piece 31. In that case, as shown in FIG. 13(b), on the first cut surface 41, for example, the lines of the laser cut marks 8 inclined to the left and lower side when viewed from the front remain.
[0053] Also, as shown in FIG. 14(a), while moving the torch 11 in a direction away from the connecting portion 27 and tilting it so as to fall backward in the traveling direction, the first protruding piece 31 can be cut. In that case, as shown in FIG. 14(b), on the first cut surface 41, when viewed from the front, the lines of the laser cut marks 8 substantially perpendicular to the first piece 21 remain. In FIGS. 13 and 14, the case where protruding pieces are provided only on the first piece 21 is illustrated. Conversely, the same applies when protruding pieces are provided only on the second piece 22. Further, protruding pieces may be provided at the rear end portions 21d of the first piece 21 and 22d of the second piece 22, and those protruding pieces can also be cut by the cutting method as described above. For example, the first protruding piece 31 may be provided at the front end portion 21c of the first piece 21, and the second protruding piece 32 may be provided at the rear end portion 22d of the second piece 22.
[0054] Next, another specific example of the die-cast product 1 will be given. FIG. 15 schematically shows another example of the die-cast product 1 immediately after casting. Further, FIG. 16 shows a state in which the unnecessary portion 3 has been removed from the die-cast product 1. FIG. 16 shows only the product portion 2. In FIG. 16, a large number of dots are attached to the cut surfaces (the first cut surface 41, the second cut surface 42, the third cut surface 43, the fourth cut surface 44, the fifth cut surface 45, the sixth cut surface 46) where the unnecessary portion 3 has been cut.
[0055] In this embodiment, the product part 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 in the case of FIG. 5. The third piece 23 extends downward from the left end portion 21b of the first piece 21. That is, the second piece 22 and the third piece 23 extend from the same side of the first piece 21. The third piece 23 is bent into a mountain fold when viewed from above with respect to the first piece 21. With respect to the first piece 21, both the second piece 22 and the third piece 23 are bent to the same side. 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 orthogonal to the first piece 21, but they may be inclined, and the respective bending angles with respect to the first piece 21 are arbitrary.
[0057] The right end portion 21a of the first piece 21 is the connection end portion with the second piece 22, and the left end portion 21b of the first piece 21 is the connection end portion with the third piece 23. The upper end portion 22a of the second piece 22 is the connection end portion with the first piece 21, and the lower end portion 22b of the second piece 22 is a free end portion. The upper end portion 23a of the third piece 23 is the connection end portion with the first piece 21, and the lower end portion 23b of the third piece 23 is a free end portion. The rear end portion 21d of the first piece 21, the rear end portion of the second piece 22, and the rear end portion of the third piece 23 are the connection end portions 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 portion 21d of the first piece 21. The fourth piece 24 is bent into a valley fold when viewed from above with respect to the first piece 21. In this embodiment, the fourth piece 24 is bent at a right angle with respect to the first piece 21, but the bending angle is arbitrary.
[0059] The fifth piece 25 extends rearward from the right end portion 24a of the fourth piece 24. The fifth piece 25 is folded in a valley fold when viewed from the front side with respect to the fourth piece 24. In the present embodiment, the fifth piece 25 is folded at a right angle with respect to the fourth piece 24, but the folding 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.
[0060] The sixth piece 26 extends rearward from the left end portion 24b of the fourth piece 24. The fifth piece 25 and the sixth piece 26 extend from the same side of the fourth piece 24. The sixth piece 26 is folded in a valley fold when viewed from the front side with respect to the fourth piece 24. With respect to the fourth piece 24, both the fifth piece 25 and the sixth piece 26 are folded to the same side. The fifth piece 25 and the sixth piece 26 face each other. In the present 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 orthogonal to the fourth piece 24, but they may be inclined, and the respective folding angles with respect 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.
[0061] The right end portion 24a of the fourth piece 24 is the connection end portion with the fifth piece 25, and the left end portion 24b of the fourth piece 24 is the connection end portion with the sixth piece 26. The front end portion of the fifth piece 25 is the connection end portion with the fourth piece 24, and the rear end portion of the fifth piece 25 is a free end portion. The front end portion of the sixth piece 26 is the connection end portion with the fourth piece 24, and the rear end portion of the sixth piece 26 is a free end portion.
[0062] In the present 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 piece is, for example, a runner portion or the like.
[0063] The first protruding piece 31 and the second protruding piece 32 are the same as in the case of 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 portion 24c of the fourth piece 24. The fifth protruding piece 35 protrudes upward from the upper end portion 25c of the fifth piece 25. The sixth protruding piece 36 protrudes upward from the upper end portion 26c of the sixth piece 26. Thus, 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 part of the entire length of the upper end portion 24c of the fourth piece 24, the fifth protruding piece 35 is provided on a part of the entire length of the upper end portion 25c of the fifth piece 25, and the sixth protruding piece 36 is provided on a part of the entire length of the upper end portion 26c of the sixth piece 26.
[0065] These first protruding piece 31 to sixth protruding piece 36 are cut and removed by the laser 10. Incidentally, typically, the case of cutting the first protruding piece 31 to the third protruding piece 33 will be described, but the case of cutting the fourth protruding piece 34 to the sixth protruding piece 36 is the same. When the first protruding piece 31 is cut, a first cut surface 41 is formed. When the second protruding piece 32 is cut, a second cut surface 42 is formed. When the third protruding piece 33 is cut, a third cut surface 43 is formed. When the fourth protruding piece 34 is cut, a fourth cut surface 44 is formed. When the fifth protruding piece 35 is cut, a fifth cut surface 45 is formed. When the sixth protruding piece 36 is cut, a sixth cut surface 46 is formed.
[0066] Figures 17 to 21 illustrate the cutting method. In Figures 17 to 21, the states of the first piece 21 to the third piece 23 are shown as viewed from the front side, but the illustrations of the fourth piece 24 to the sixth piece 26 are omitted. Figure 17(a) shows an example of the cutting method. When cutting the first protruding piece 31, the torch 11 is installed above the first protruding piece 31. When cutting the second protruding piece 32, the torch 11 is installed on the right side of the second protruding piece 32. When cutting the third protruding piece 33, the torch 11 is installed on the left side of the third protruding piece 33. That is, the torch 11 is installed 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 from the mountain-fold side toward each protruding piece.
[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 not perpendicular to the first protruding piece 31 but is inclined so as to fall to the left side which is the rear side in the traveling direction. That is, the torch 11 is tilted to the left by a predetermined angle, and the laser 10 is obliquely inclined 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 and irradiated onto the first protruding piece 31. In this way, by irradiating the laser 10 obliquely onto the first protruding piece 31 from the rear side to the front side in the traveling direction, the molten metal 6 can be flown straight downward substantially. That is, the molten metal 6 can be flown in a direction substantially orthogonal (substantially normal direction) to the first piece 21. Therefore, it is possible to suppress the adhesion of the molten metal 6 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 in 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 blown obliquely downward. That is, the molten metal 6 can be blown in the 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 in 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 blown obliquely downward. That is, the molten metal 6 can be blown in the 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. A first cut surface 41 is formed at the front end portion 21c of the first piece 21 by cutting the first protruding piece 31, a second cut surface 42 is formed at the front end portion 22c of the second piece 22 by cutting the second protruding piece 32, and a third cut surface 43 is formed at the front end portion 23c of the third piece 23 by cutting the third protruding piece 33.
[0071] The grain of the laser cutting mark 8 on the first cutting plane 41 is substantially perpendicular to the first piece 21 when viewed from the front and extends from the upper side to the lower side. That is, the grain of the laser cutting mark 8 on the first cutting plane 41 is a grain that is substantially perpendicular from the mountain-fold side surface to the valley-fold side surface when viewed from the front. The grain of the laser cutting mark 8 on the second cutting plane 42 is inclined to the left and lower when viewed from the front. That is, the grain of the laser cutting mark 8 on the second cutting plane 42 is inclined in the 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 grain of the laser cutting mark 8 on the third cutting plane 43 is inclined to the right and lower when viewed from the front. That is, the grain of the laser cutting mark 8 on the third cutting plane 43 is inclined in the direction away from the first piece 21 from the mountain-fold side surface to the valley-fold side surface when viewed from the front.
[0072] It may be as shown in Fig. 18(a). 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 for cutting the first protruding piece 31 is opposite to that in Fig. 17(a), and the first protruding piece 31 is cut from its right end 31a towards its left end 31b. That is, the advancing direction of the torch 11 is to the left. In this case, the torch 11 is inclined so as to fall to the right, which is the rear side in the advancing direction, with respect to the first protruding piece 31. That is, the torch 11 is tilted to the right by a predetermined angle, and the laser 10 is obliquely inclined from the right side, which is the rear side in the advancing direction, towards the left side, which is the front side in the advancing direction, and irradiated onto the first protruding piece 31. Thereby, when cutting the first protruding piece 31, the molten metal 6 can be flown straight downward substantially 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. Incidentally, in this case, after cutting the second protruding piece 32, the first protruding piece 31 can be continuously cut in one 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 are cut. The grains of the respective laser cutting marks 8 on the first cutting plane 41, the second cutting plane 42, and the third cutting plane 43 are the same as those shown in Fig. 17(b).
[0074] It may be as shown in Fig. 19(a). 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 in the same manner as in Fig. 17(a). However, the torch 11 is inclined so as to be tilted upward, which is the front side in the advancing direction. By tilting the torch 11 forward in the advancing direction in this way, the laser 10 can be obliquely irradiated onto the second protruding piece 32 and the third protruding piece 33 from the front side to the rear side in the advancing direction. By obliquely irradiating the laser 10 onto the second protruding piece 32 and the third protruding piece 33 from the front side to the rear side in the advancing direction, the molten metal 6 can be obliquely ejected more 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 are cut. The grain of the laser cutting mark 8 on the first cutting surface 41 is the same as that shown in Fig. 17(b). On the other hand, the grain of each laser cutting mark 8 on the second cutting surface 42 and the third cutting surface 43 is inclined more downward than that shown in Fig. 17(b).
[0076] It may be as shown in Fig. 20(a). The cutting of the first protruding piece 31 is the same as in the case of 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 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 connecting portion 27. Then, the torch 11 is tilted so as to fall on the upper side which is the rear side in the traveling direction. By tilting the torch 11 to the rear side in the traveling direction in this way, the laser 10 can be obliquely irradiated on 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 on 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 flown substantially horizontally so as not to approach the first piece 21. That is, the molten metal 6 can be flown in a direction substantially orthogonal to the second piece 22 and the third piece 23. Thereby, the adhesion of the molten metal 6 to the first piece 21 can be suppressed.
[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. The streaks of the laser cutting marks 8 on the first cutting surface 41 are the same as those shown in Fig. 17(b). On the other hand, the streaks of the laser cutting marks 8 on the second cutting surface 42 and the third cutting surface 43 are substantially perpendicular to the second piece 22 and the third piece 23, respectively. That is, the streaks of the laser cutting marks 8 on the second cutting surface 42 and the third cutting surface 43 are streaks that extend substantially vertically from the mountain-fold side surface to the valley-fold side surface when viewed from the front. In this way, in the case of Fig. 20(b), all the streaks of the laser cutting marks 8 are streaks that extend substantially vertically from the mountain-fold side surface to the valley-fold side surface when viewed from the front.
[0078] You may do it as shown in Fig. 21(a). The cutting of the first protruding piece 31 is the same as in the case of Fig. 17(a). Also, the moving direction of the torch 11 when cutting the second protruding piece 32 and the third protruding piece 33 is the same as in the case of Fig. 17(a). What is different from the case of 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 inclined so as to be tilted downward, which is the rear side in the advancing direction. By tilting the torch 11 backward in the advancing direction in this way, the laser 10 can be obliquely irradiated onto the second protruding piece 32 and the third protruding piece 33 from the rear side to the front side in the advancing direction. By irradiating the laser 10 obliquely onto the second protruding piece 32 and the third protruding piece 33 from the rear side to the front side in the advancing direction, the molten metal 6 can be flown substantially horizontally so as not to approach the first piece 21. That is, the molten metal 6 can be flown in a direction substantially orthogonal to the second piece 22 and the third piece 23. Thereby, the adhesion of the molten metal 6 to the first piece 21 can be suppressed.
[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 are cut. The streaks of the laser cutting marks 8 are the same as those shown in Fig. 20(b).
[0080] In addition, in Fig. 15, protruding pieces were provided on all of the first piece 21, the second piece 22, and the third piece 23. However, protruding pieces may be provided on only, for example, one of these three pieces or only on two of these three pieces. The same applies to the fourth piece 24, the fifth piece 25, and the sixth piece 26. Also, the fourth piece 24 was bent in a valley-fold shape (bent upward) when viewed from above with respect to the first piece 21. Conversely, the fourth piece 24 may be bent in a mountain-fold shape (bent downward) when viewed from above with respect to the first piece 21. Also, the fourth piece 24 to the sixth piece 26 may be omitted.
Explanation of Reference Numerals
[0081] 1 Die-cast product 2 Product part 3 Excluded Portion 4 Protrusion 4a First Surface 4b Second Surface 4c Right End 4d Left End 5 Melted Portion 6 Melted Metal 7 Cut Surface 8 Laser Cutting Mark 10 Laser 11 Torch 21 First Piece 21a Right End (One End in the First Direction) 21b Left End (The Other End in the First Direction) 21c Front End (One End in the Second Direction) 21d Rear End (The Other End in the Second Direction) 22 Second Piece 22a Upper End 22b Lower End 22c Front End 23 Third Piece 23a Upper End 23b Lower End 23c Front End 24 Fourth Piece 24a Right End 24b Left End 24c Upper End 25 Fifth Piece 25c Upper End 26 Sixth Piece 26c Upper End 27 Connection Portion 31 First Protrusion 31a Right End 31b Left End 32 Second Protrusion 32a Upper End 32b Lower End 33 Third Protrusion 33a Upper End 33b Lower End 34 Fourth Protrusion 35 Fifth Protrusion 36 Sixth Protrusion 41 First Cut Surface 42 Second Cut Surface 43 Third Cut Surface 44 Fourth cutting plane 45 Fifth cutting plane 46 Sixth cutting plane 101 First direction 102 Second direction 103 Third direction
Claims
1. A method for cutting unnecessary portions from a product portion of a cast die-cast product, comprising: 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 the first direction, the other end of the first piece in the first direction is a free end; the unnecessary portion has a first protruding piece protruding in the second direction at one end of the first piece in a second direction perpendicular to the first direction, a cutting step of irradiating a laser from the mountain fold side to cut off the unnecessary portion, The cutting step is a method for cutting unnecessary portions of a die-cast product, and includes a step of advancing a laser from the free end of the first piece toward the connecting end with the second piece to cut the first protruding piece.
2. The end of the second piece opposite to the end connected to the first piece is a free end, the unnecessary portion has a second protruding piece protruding in the second direction at one end of the second piece in the second direction, 2. A method for cutting unnecessary portions of a die-cast product according to claim 1, wherein the cutting step includes a step of advancing a laser from the free end of the second piece toward the connecting end with the first piece to cut the second protruding piece.
3. A method for cutting unnecessary portions from a product portion of a cast die-cast product, comprising: the product portion has a first piece, 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 the first direction, and a third piece that is bent in a mountain fold relative to the first piece and extends from the other end of the first piece in the first direction, an end of the second piece opposite to the end connected to the first piece is a free end; the unnecessary portion has a second protruding piece protruding in the second direction at one end of the second piece in a second direction perpendicular to the first direction, a cutting step of irradiating a laser from the mountain fold side to cut off the unnecessary portion, The cutting step is a method for cutting unnecessary portions of a die-cast product, and includes a step of advancing a laser from the free end of the second piece toward the connection end with the first piece to cut the second protruding piece.
4. The end of the third piece opposite to the end connected to the first piece is a free end, the unnecessary portion has a third protruding piece that protrudes in the second direction from one end of the third piece in the second direction, 4. A method for cutting off unnecessary portions of a die-cast product according to claim 3, wherein the cutting step includes a step of cutting off the third protruding piece by irradiating a laser from the free end of the third piece toward the connecting end with the first piece.
5. A die-cast product from which unnecessary parts have been cut off, 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, a cut surface having a streak-like laser cutting mark is provided at one end of the first piece in a second direction perpendicular to the first direction; The laser cutting marks are lines that are inclined in a direction away from the second piece from the mountain fold surface to the valley fold surface, in this die-cast product.