Sequential forming method

Abstract

To prevent or suppress unexpected deformation of a plate material without using a dedicated jig.SOLUTION: According to the present invention, in a sequential forming method of a plate material P1, a structure easy to be buckled and deformed is formed at a position not becoming a final product in the plate material, sequential forming is performed, and the plate material is heated in a state of restraining the periphery of the plate material.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a sequential forming method.

Background Art

[0002] Parts such as body panels are produced not only by press working using a mold but also by a method that does not use a mold when producing only a small number of parts like repair parts. Such a processing method can be called die-less forming (incremental forming).

[0003] Die-less forming is a method that applies sequential forming in which a plate material is deformed little by little by a tool attached to a robot or the like. In the prior art related to die-less forming, a blank holder that can move up and down is provided, a forming tool that forms a pair with a receiving jig is movably attached to a processing apparatus, and after performing a forming process by lowering the blank holder, the first to third annealing processes are carried out (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When performing sequential forming on a plate material as in Patent Document 1, heat treatment such as annealing may be performed. The inventors of the present invention focus on suppressing the deformation of the plate material so as to be contrary to the assumed shape during the above heat treatment. In order to suppress the unexpected deformation of the plate material, it is conceivable to prepare a dedicated jig that matches the part shape, but in that case, there are problems in terms of cost and the like.

[0006] An object of the present invention is to suppress the deformation of a plate material contrary to expectations without using a dedicated jig.

Means for Solving the Problems

[0007] One aspect of the present invention is a sequential forming method for forming a plate material. In this method, a structure that is prone to buckling is formed at a position on the plate material that does not become the final product. Then, sequential forming is performed on the plate material, and the plate material is heated while restraining the periphery of the plate material.

Advantages of the Invention

[0008] According to the above forming method, it is possible to suppress the plate material from being deformed contrary to expectations without using a dedicated jig.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] (Embodiment) Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. In the drawings, the same members are denoted by the same reference numerals, and duplicate descriptions are omitted. In the drawings, the sizes and ratios of the respective members may be exaggerated for easy understanding of the embodiments and may be different from the actual sizes and ratios.

[0011] The sequential forming according to the present embodiment can be used, for example, for large parts such as vehicle body panels when not mass-producing parts such as repair parts. Since the sequential forming according to the present embodiment forms the plate material P1 without using a mold, it can also be called die-less forming (incremental forming). By using die-less forming for the forming of the plate material P1 and suppressing springback, a product with relatively high accuracy can be manufactured at a relatively low cost. The material of the plate material P1 is not particularly limited, but aluminum or the like that is prone to springback can be used.

[0012] FIG. 1 is a block diagram showing the apparatus configuration of the sequential forming method according to the present embodiment. The apparatus configuration of the sequential forming according to the present embodiment includes an input unit 10, a position information acquisition unit 20, a storage unit 30, a forming unit 40, and an apparatus control unit 50, as shown in FIG. 1. Details will be described below.

[0013] (Input Unit) The input unit 10 is used for an operator or the like to input and instruct the shape of the final product formed by the plate material P1, the position information acquired by the position information acquisition unit 20, the content stored in the storage unit 30, the tool path of the plate material P1 formed by the forming unit 40, and the control content of the device control unit 50, etc. The input unit 10 can include at least any one of a mouse, a keyboard, a touch screen, etc. In addition, the device used in the sequential forming method according to the present embodiment can communicate with the Internet or the like, or can connect storage media such as various disks and memory sticks, so as to capture shape data such as drawings of parts to be manufactured.

[0014] (Position Information Acquisition Unit) The position information acquisition unit 20 is configured to be able to acquire information regarding the path of the tool input and instructed by the input unit 10. The position information acquisition unit 20 can be configured to include a light projecting unit that irradiates light to image the plate material P1 to be processed, a light receiving unit that receives the light from the light projecting unit, a display that processes and displays the information received by the light receiving unit, and the like. As a device including the above-described light projecting unit, light receiving unit, display, etc., a three-dimensional shape measuring device or a 3D scanner can be cited. By imaging the plate material P1 formed using the position information acquisition unit 20, data having the coordinate position at a specific part of the plate material P1 can be acquired.

[0015] (Storage Unit) The storage unit 30 is configured to be able to store information such as applications necessary for sequential forming, the physical properties of the plate material P1 input and instructed by the operator, the shape of the final product, the position information by the position information acquisition unit 20, the forming information by the forming unit 40, and the control content by the device control unit 50. The storage unit 30 can include a RAM and a ROM. In the storage unit 30, in addition to the position information acquired by the above-described position information acquisition unit 20, data regarding the target shape can be stored. In the storage unit 30, drawing data, shape data of parts as design data, applications necessary for analysis and data of analysis results described later, and data regarding the tool path calculated by the device control unit 50 can be stored.

[0016] (Forming unit) FIG. 2 is a diagram showing a forming unit 40 included in an apparatus for a sequential forming method according to the present embodiment. The forming unit 40 is configured to perform forming on a plate material P1 under the control of an apparatus control unit 50 based on a tool path stored in a storage unit 30. The forming unit 40 can include, for example, a multi-axis robot 41 having a linear tool 42 or the like attached to its tip as an example.

[0017] The forming unit 40 creates a portion on the plate material P1 that is likely to undergo buckling deformation before or after performing die-less forming. In this specification, this portion is referred to as an easily deformable portion. The plate material P1 can be formed into a vehicle bonnet or the like, and the periphery of the plate material P1 or the like is trimmed until it becomes a product, but the easily deformable portion is set to a portion that does not remain as a final product.

[0018] In addition, in FIG. 2, one robot 41 is illustrated, but if sequential forming is performed without using a mold, the number of robots does not have to be one. Further, the forming unit 40 can include, in addition to the multi-axis robot 41, a jig 43 for fixing the outer peripheral portion of the plate material P1 or the vicinity of the outer peripheral portion, a mounting portion 44 such as a table for installing the plate material P1, and the like. By the forming unit 40, sequential forming is performed on the plate material P1.

[0019] Further, the forming unit 40 includes a hot air blower as a heat treatment unit 45. Thereby, the plate material P1 can be heated on the machine without using a heating furnace or the like. In addition, the heating by the hot air blower related to the heat treatment unit 45 can be set so that the order is from the product portion to the portion other than the product portion, from the portion that is likely to buckle among the plate materials P1 toward the portion that is likely to buckle (see the arrow in FIG. 3). Thereby, it is possible to concentrate thermal expansion on the portion that is likely to buckle and avoid buckling in the product portion.

[0020] (Apparatus control unit) The device control unit 50 includes a CPU and the like, and is configured to control the input unit 10, the position information acquisition unit 20, the storage unit 30, and the forming unit 40. Further, based on information such as the material and thickness of the plate material P1 and the tool path stored in the storage unit 30 through the input unit 10, the device control unit 50 can sequentially perform forming on the plate material P1 using the forming unit 40.

[0021] (Forming method) Next, the sequential forming method according to the present embodiment will be described. FIG. 3 is a diagram showing the plate material P1 according to the present embodiment, and FIG. 4 is a flowchart showing an outline of the sequential forming method according to the present embodiment. Briefly describing the sequential forming method according to the present embodiment with reference to FIG. 4, it includes sequential forming (S1), forming of a deformable part (S2), and heating (S3). Details will be described below.

[0022] First, in this forming method, the plate material P1 is set on the placement part 44 and the necessary parts are constrained by the jig 43. Then, the operator inputs and designates the forming path of the tool 42 required for forming the plate material P1 through the input unit 10.

[0023] Next, when a switch (not shown) or the like is pressed, the device control unit 50 executes the program designated by the operator from the storage unit 30 and operates the tool 42 of the robot 41 according to the input program. As a result, the robot 41 uses the tool 42 and sequentially forms the plate material P1 according to the program stored in the storage unit 30 (S1).

[0024] Next, the robot 41 forms a deformable part d1 on the plate material P1. In the present embodiment, as shown in FIG. 3, four hole parts are formed as the deformable part d1 at the lower right of the plate material P1 (S2). Then, the plate material P1 is heated (S3).

[0025] Here, the use of the deformable part d1 will be described. FIG. 5 is a diagram showing the behavior of a conventional plate material when heating the plate material after sequential forming, and FIG. 6 is a diagram showing the behavior of the plate material of the present embodiment when heating the plate material after sequential forming.

[0026] After successive forming, the periphery of the plate material P1 is constrained and heated. At this time, due to the difference in the thermal expansion coefficients of the plate material P1 and the constraining jig, the part may be deformed so as to be clogged, and buckling may occur at a part where the displacement amount is large, and the part pr1 may break (see FIG. 5).

[0027] In this regard, in the present embodiment, a readily deformable portion d1 is set at a portion of the plate material P1 that does not become the final product. Therefore, buckling preferentially occurs from the readily deformable portion d1, and even if the readily deformable portion d1 buckles and breaks during successive forming, deformation of other portions can be suppressed so that buckling does not occur in other portions. As the installation position of the readily deformable portion, it can be provided at a position where buckling occurs or in the vicinity thereof during heating. By configuring in this way, the position where a structure that easily buckles can be simply provided can be determined. The position where buckling occurs can be set to be a portion pr2 other than the final product in the plate material P1 as shown in FIGS. 3 and 6.

[0028] FIGS. 7 and 8 are views showing plate materials P2 and P3 according to a modification of FIG. 3, and FIG. 9 is a view showing deformation of the plate material in a cross section along line 9-9 of FIG. 8. Specific examples of the shape of the readily deformable portion include the hole portion shown in the plate material P1 of FIG. 3, the long hole as the readily deformable portion d2 shown in the plate material P2 of FIG. 7, or the emboss (convex shape) as the readily deformable portion d3 shown in the plate material P3 of FIG. 8. By using the readily deformable portion described above, it is possible to eliminate the use of a dedicated jig that matches the part shape in order to suppress (permanent) deformation during heating.

[0029] (Modification 1) Hereinafter, modifications of the above embodiment will be described. In the following, configurations different from the above-described embodiment will be described, and since other configurations are the same as those of the above-described embodiment, descriptions of common configurations will be omitted. FIGS. 10 and 11 are views for explaining a method of forming a plate material according to Modification 1.

[0030] In the above embodiment, it has been described that the easily deformable portion is set at a portion of the plate material P1 that does not become the final product. However, the setting position of the easily deformable portion can utilize simulation by numerical analysis. Thereby, the position where a shape that is likely to buckle can be easily determined. As the content of the numerical analysis, thermal expansion analysis using the finite element method can be performed. In this numerical analysis, the constrained portion and the input load in the plate material P1 can be specified. The condition setting of the numerical analysis is performed through the input unit 10, the application for performing the numerical analysis and the data of the analysis result are stored in the storage unit 30, and the execution of the analysis can be performed by the device control unit 50.

[0031] If the input is set so as to reproduce the change in heat over time as the input condition for heat in the simulation, it will take a considerably long time to obtain the analysis result. On the other hand, the inventors have found that even if it is analyzed and set that the temperature of the entire plate material has risen uniformly, the tendency of the portion where the displacement amount becomes large in the plate material is almost the same as when the change in heat is set over time. Thereby, among the thermal expansion analyses, the analysis result regarding the position that is easily buckled can be easily obtained by setting that heat is uniformly input to the plate material as the heat input condition. That is, when the analysis result as shown in FIG. 10 is obtained, by setting the easily deformable portion at the portion of the plate material that does not become the final product in the same manner as FIG. 3 of the first embodiment, it can be confirmed that the analysis result after setting the easily deformable portion is good (see FIG. 11).

[0032] (Modification Example 2) In Modification Example 1, it has been described that the position where the easily deformable portion is set can be determined as a portion that is likely to buckle by numerical analysis. However, the position where the easily deformable portion is set can also be set at a location with a large curvature in the boundary between the formed portion pr3 formed on the curved surface by, for example, die-less forming and the peripheral flange portion pr4 (see the red circle in FIG. 10). Since buckling can also occur starting from a location with a large curvature, by providing the easily deformable portion in this way, buckling can be preferentially generated starting from this portion, and buckling of other portions that unintentionally become products as in the prior art can be suppressed.

[0033] (Modification Example 3) FIG. 12 is a diagram showing the position where the easily deformable portion is set in Modification Example 3 of the embodiment. FIG. 13 is a diagram showing a state in which the easily deformable portion is set in the plate material P4 according to Modification Example 3.

[0034] In Modification Example 2, it was explained that the easily deformable portion is set at a location with a large curvature among the boundaries between the portion formed into a curved surface by die-less forming and the peripheral flange portion. However, the inventors conceived the idea that a flat portion that continues in addition to the above is likely to buckle. Therefore, the easily deformable portion d4 can be provided at a portion where a surface with a small curvature, such as the portion pr5 shown in gray in FIG. 12, continues in the plate material P4 (see FIG. 13). Thereby, the said part can be made to buckle preferentially, and it can prevent or suppress that other parts buckle unintentionally.

[0035] (Modification Example 4) FIG. 14 is a diagram showing the heating order of the plate material by the heat treatment portion according to Modification Example 4. In the first embodiment, as shown in FIG. 3, it was explained that the hot air is blown so that the heating order becomes a portion where buckling is likely to occur from the product portion. However, in addition to the above, the heating order can also be set to go from the center, which is the product portion, toward the outer peripheral portion as shown by the arrow in FIG. 14. By configuring in this way, it is possible to avoid buckling occurring in the product portion by concentrating the thermal expansion on the outer peripheral portion.

[0036] Note that the present invention is not limited only to the above-described embodiments, and various modifications are possible within the scope of the claims. In the above, the easily deformable portion was formed after sequential forming, but sequential forming may be performed after forming the easily deformable portion. By configuring in this way as well, deformation of other parts can be suppressed in the same manner as above.

[0037] Also, the following embodiments are also included in the scope of the present invention: the sequential forming method according to claim 1 having the features of claim 2; the sequential forming method according to claim 1 or claim 2 having the features of claim 3; the sequential forming method according to claim 3 having the features of claim 4; the sequential forming method according to claim 4 having the features of claim 5; the sequential forming method according to any one of claims 1 to 5 having the features of claim 6; the sequential forming method according to any one of claims 1 to 6 having the features of claim 7; the sequential forming method according to claim 3 having the features of claim 8; the sequential forming method according to any one of claims 1 to 8 having the features of claim 9; the sequential forming method according to any one of claims 1 to 9 having the features of claim 10; the sequential forming method according to claim 10 having the features of claim 11; the sequential forming method according to claim 10 having the features of claim 12; the sequential forming method according to any one of claims 1 to 12 having the features of claim 13.

Explanation of Reference Signs

[0038] 45 Heat treatment section (hot air blower), P1, P2, P3, P4 Sheet materials, pr3 Forming portion, pr4 Flange portion.

Claims

1. In a sequential forming method of a sheet material, a structure that is likely to undergo buckling deformation is formed at a position that does not become the final product among the sheet materials, the sheet material is sequentially formed, A sequential forming method in which the sheet material is heated while restraining the periphery of the sheet material.

2. The sequential forming method according to claim 1, wherein the shape that is likely to undergo buckling deformation includes a hole or a convex shape.

3. The sequential forming method according to claim 1, wherein the shape that is likely to undergo buckling deformation is formed at or near a position where buckling occurs during heating.

4. The sequential forming method according to claim 3, wherein the position that is likely to undergo buckling deformation is specified by numerical analysis.

5. The sequential forming method according to claim 4, wherein the numerical analysis is performed assuming that the temperature of the entire sheet material rises uniformly.

6. The sequential forming method according to claim 1, wherein the shape that is likely to buckle is formed near a location with a large curvature at the boundary between the formed portion and the peripheral flange portion.

7. The sequential forming method according to claim 1, wherein the shape that is likely to buckle is formed at a position where surfaces with a small curvature are continuous.

8. The sequential forming method according to claim 3, wherein the shape that is likely to buckle is determined such that the buckling site during heating is a site other than the final product.

9. The sequential forming method according to claim 1, wherein the sheet material is formed by sequential forming and springback is suppressed.

10. The sequential forming method according to claim 1, wherein the sheet material is heated by a hot air blower.

11. The sequential forming method according to claim 10, wherein the heating of the sheet material is performed so as to go from the product portion toward the shape that is likely to buckle.

12. The sequential forming method according to claim 10, wherein the heating of the sheet material is performed so as to go from the product portion toward the outer peripheral portion.

13. The sequential forming method according to claim 1, wherein the sheet material contains aluminum.

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