Successive forming method

Abstract

To solve the problem that it is difficult to improve form accuracy of mold goods in conventional sequential forming methods.SOLUTION: A sequential forming method is given in which a tip of a bar-like tool T is pressed and moved against one principal surface of a metal plate W whose periphery is retained to form the metal plate W into a three-dimensional shape. The sequential forming method includes a pedestal 2 arranged at the other principal surface side of the metal plate W, where the pedestal 2 has a flat surface 2S which faces an apical surface of the bar-like tool T, the pedestal is retractable at least regarding the metal plate W, the pedestal 2 follows movement of the bar-like tool T to form the metal plate W while the bar-like tool T and the pedestal 2 sandwiches the metal plate W, and distortion difference between front and back of the metal plate W at a portion where the rod-like tool T contacts with to improve form accuracy of a mold good and quality while suppressing apparatus cost and manufacturing cost.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sequential forming method and a sequential forming apparatus for forming a metal plate into a three-dimensional shape by pressing and moving a rod-shaped tool against the metal plate.

Background Art

[0002] As a conventional sequential forming method, for example, there is one described in Patent Document 1. The sequential forming method described in Patent Document 1 uses a first tool disposed on one surface side of a plate-shaped workpiece and a second tool disposed on the other surface side of the workpiece. The first tool has a first curved surface protruding hemispherically toward the workpiece. The second tool has a convex second curved surface that forms an annular shape and is in line contact with the first curved surface along the opening thereof. And the above sequential forming method provides a forming apparatus and a forming method capable of suppressing a reduction in plate thickness by moving the first tool and the second tool relative to each other while bringing the first curved surface and the second curved surface into contact with the forming surface of the workpiece to form the workpiece.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the conventional sequential molding method described above uses a rod-shaped first tool with a spherical first curved surface and a second tool with an annular second curved surface, making it difficult to improve the shape accuracy of the molded product and resulting in the problem of tool marks being easily left behind. Sequential molding methods that are less likely to leave tool marks include a method in which the rod-shaped tool is in contact with only one side of the metal plate during molding, or a method in which a lower mold is placed on the opposite side of the rod-shaped tool, and the metal plate is molded along the lower mold by pressing and moving the rod-shaped tool. However, in the former case, the difference in distortion between the front and back sides at the contact point of the rod-shaped tool becomes large, making it difficult to improve the shape accuracy of the molded product, and in the latter case, it is necessary to prepare a lower mold according to the molded product, which results in increased equipment costs and manufacturing costs.

[0005] The present invention has been made in view of the above-mentioned conventional circumstances, and aims to provide a sequential molding method and sequential molding apparatus that can reduce the difference in distortion between the front and back surfaces of a metal plate at the contact portion of a rod-shaped tool, while suppressing equipment costs and manufacturing costs, thereby improving the shape accuracy and quality of the molded product. [Means for solving the problem]

[0006] The sequential forming method according to the present invention forms a metal plate into a three-dimensional shape by pressing the tip of a rod-shaped tool against one main surface of the metal plate, which is held around its perimeter, and moving it. In this sequential forming method, a tool is placed on the other main surface side of the metal plate. one A support stand is used. This support stand faces the tip surface of the rod-shaped tool. Furthermore, the size is equivalent to the area to be formed of the metal plate. It has a plane, With the Z-axis as the direction of movement relative to the metal plate, movement occurs in three mutually orthogonal directions: X, Y, and Z. It is possible. And the sequential forming method involves sandwiching the metal plate between a rod-shaped tool and a support base, and then using the rod-shaped tool 3-axis This method is characterized by forming a metal plate by having a support base follow the movement of the metal.

[0007] The sequential molding apparatus according to the present invention is a sequential molding apparatus used in the above-described sequential molding method, and is characterized by comprising a clamping device for holding the periphery of a metal plate, a rod-shaped tool positioned on one main surface side of the metal plate, a support base positioned on the other main surface side of the metal plate, and a control device for controlling the position of the support base based on pre-set movement path data of the rod-shaped tool. [Effects of the Invention]

[0008] The sequential molding method and sequential molding apparatus according to the present invention, by adopting the above configuration, can reduce equipment and manufacturing costs by using a support base that can accommodate various shapes of molded products, while also reducing the difference in distortion between the front and back surfaces of the metal plate at the contact point of the rod-shaped tool, thereby improving the shape accuracy and quality of the molded product. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view showing a sequential molding apparatus to which the sequential molding method according to the present invention can be applied, in the first embodiment of the sequential molding method according to the present invention. [Figure 2] Figure 1 is a plan view illustrating the drive mechanism of the support stand. [Figure 3] These are a side view (A) and a top view (B) showing the relationship between the rod-shaped tool and the support base. [Figure 4] This is a side view following Figure 1, showing the metal sheet forming process. [Figure 5] Following Figure 4, this is a side view showing the metal sheet forming process. [Figure 6] This is a side view of the key part showing the relationship between the rod-shaped tool and the forming angle of the metal plate. [Figure 7] The side views (A) to (C) show the relationship between the various shapes of the rod-shaped tool and the support base. [Figure 8] These are cross-sectional diagrams illustrating the relationship between the rod-shaped tool and the metal plate when the forming angle is large (A), cross-sectional diagrams illustrating the changes in the metal plate during forming (B), and cross-sectional diagrams illustrating the changes in the metal plate after forming (C). [Figure 9]Cross-sectional explanatory view (A) of the main part showing the relationship between the bar-shaped tool and the metal plate when the forming angle is small, cross-sectional explanatory view (B) showing the change of the metal plate during forming, and cross-sectional explanatory view (C) showing the change of the metal plate after forming. [Figure 10] In the second embodiment of the sequential forming method according to the present invention, it is a side view showing a sequential forming apparatus to which the method is applicable. [Figure 11] It is a side view showing the forming process of the metal plate following FIG. 11.

Mode for Carrying Out the Invention

[0010] <First Embodiment> FIG. 1 is a view showing a sequential forming apparatus to which the sequential forming method according to the present invention is applicable. The illustrated sequential forming apparatus basically includes a clamp device 1 that holds the periphery of the metal plate W, a bar-shaped tool T disposed on one main surface side (upper side in FIG. 1) of the metal plate W, a pedestal 2 disposed on the other main surface side (lower side) of the metal plate W, and a control device 3 that controls the position of the pedestal 2 based on preset movement path data of the bar-shaped tool T.

[0011] The metal plate W is a flat plate that is the material of the formed product. In this embodiment, it is held horizontally by the clamp 1 at the periphery. Note that the sequential forming method according to the present invention is a die-less forming that does not use a mold. In this sequential forming method, it is also possible to hold the metal plate W in a vertical state or an inclined state, and the bar-shaped tool T and the pedestal 2 are arranged according to the posture of the metal plate W. The clamp device 1 includes a fixed lower frame portion 1A and an upper frame portion 1B that can move up and down with respect to the lower frame portion 1A, and firmly clamps the periphery of the metal plate W between the lower frame portion 1A and the upper frame portion 1B.

[0012] The bar-shaped tool T is held in a posture with its axis in the vertical direction in the illustrated example, and the lower tip portion has a well-known appropriate shape such as a spherical shape, and is driven in three orthogonal axial directions by the tool driving device 4.

[0013] The tool driving device 4 can use a multi-axis control type work robot, a NC machine tool, etc. The tool driving device 4 in the illustrated example moves the mounted bar-shaped tool T in the horizontal X and Y directions and the vertical Z direction. Note that the bar-shaped tool T can also be rotated around each axis.

[0014] The receiving base 2 has a plane 2S facing the tip surface of the bar-shaped tool T and is at least retractable with respect to the metal plate W. In this embodiment, taking the direction of advancing and retreating with respect to the metal plate W as the Z-axis direction, it is movable in the three mutually perpendicular X, Y, and Z axis directions. That is, the receiving base 2 only needs to have the plane 2S regardless of the various shapes of the molded product, and is driven in the three mutually perpendicular axis directions by the receiving base driving device 5 shown in FIGS. 1 and 2.

[0015] Further, as shown in FIGS. 3(A) and (B), the receiving base 2 of this embodiment is substantially square in plan view and has a plane 2S having an area equal to or slightly larger than the projected area in the axial direction of the bar-shaped tool T, and also has a chamfered portion R at the shoulder portion around the plane 2S.

[0016] The receiving base driving device 5 includes a frame 5A having a square frame shape, a lifter 5B that drives the frame 5A to move up and down in a horizontal state, a beam 5C installed between one pair of opposing sides (the upper and lower opposing sides in FIG. 2) of the frame 5A, and a slide 5D disposed on the beam 5C. The beam 5C is reciprocally movable in the longitudinal direction of the opposing sides (the left and right directions in FIG. 2) by a driving mechanism not shown. Also, the slide 5D is reciprocally movable in the longitudinal direction of the beam 5C (the up and down direction in FIG. 2) by a driving mechanism not shown, and the receiving base 2 is fixed to its upper part.

[0017] Thereby, in FIG. 2, the receiving base 2 is movable in the X-axis direction by the beam 5C, movable in the Y-axis direction by the slide 5D, and further, in FIG. 1, movable in the Z-axis direction by the lifter 5B.

[0018] The control device 3 is a computer that has pre-programmed data for driving the rod-shaped tool T used to form a metal plate W into a molded product, including the entire movement path from the starting point to the ending point of the molding process, the movement speed, and the amount of pressure applied to the metal plate W. The control device 3 has the function of controlling the position of the support base 2 to follow the movement of the rod-shaped tool T based on the pre-set movement path data of the rod-shaped tool T.

[0019] More precisely, the control device 3 controls the tool drive device 4 so that the rod-shaped tool T moves along a set movement path, and also controls the support base drive device 5 so that the support base 2 follows the movement of the rod-shaped tool T.

[0020] Next, the sequential forming method will be explained along with the operation of the sequential forming apparatus described above. In a well-known sequential forming method, as shown in Figure 1, the tip of a rod-shaped tool T is pressed against a metal plate W held around its perimeter by clamps 1 and moved. Specifically, after moving the rod-shaped tool T along a circular path, a pitch feed is performed to displace the rod-shaped tool T inward and downward by a predetermined amount, and the operation of moving along the next circular path and pitch feed is repeated. In this way, the sequential forming method moves the rod-shaped tool T in a contour line manner, forming the metal plate W by gradually pushing down the bottom, as shown in Figures 4 and 5, and finally obtaining a molded product with a three-dimensional shape.

[0021] In the sequential forming method, the surface of the metal plate W that contacts the rod-shaped tool T is stretched, so the difference between the residual stress on the surface contacted by the rod-shaped tool T and the residual stress on the opposite surface, i.e., the difference in strain between the front and back sides, becomes large, making it easier for dimensional deterioration phenomena such as twisting to occur.

[0022] In contrast, in the sequential molding method according to the present invention, when performing sequential molding as described above, the metal plate W is sandwiched between a rod-shaped tool T and a support base 2, and the support base 2 is made to follow the movement of the rod-shaped tool T. In the illustrated example, as shown in Figure 4, the support base 2 is moved in the X, Y, and Z axes to follow the circumferential movement and pitch feed of the rod-shaped tool T, thereby forming the outer inclined surface K1 on the metal plate W. Subsequently, as shown in Figure 5, the inner inclined surface K2 is formed by the cooperation of the rod-shaped tool T and the support base 2, and a molded product having a stepped recessed shape is obtained.

[0023] In other words, in the sequential forming method described above, the metal plate W is sandwiched between a rod-shaped tool T and a support base 2 positioned on its opposite side, and the metal plate W is formed by squeezing it from both sides. This reduces the difference in distortion between the front and back sides of the metal plate W, thereby suppressing forming defects such as twisting caused by the difference in distortion.

[0024] Furthermore, in a more preferred embodiment of the sequential forming method, the forming angle θ is defined as the angle between the main surface of the metal plate W before forming and the formed inclined surfaces (K1, K2), and the distance d between the rod-shaped tool T and the support base 2 is controlled within a range less than or equal to the thickness t0 of the metal plate W, according to the magnitude of the forming angle θ.

[0025] The rod-shaped tool T can have various tip shapes, such as a spherical tip as shown in Figure 7(A), a flat tip with a chamfered edge as shown in Figure 7(B), or a tip with different curvatures than the chamfered edge as shown in Figure 7(C). In the above sequential forming method, rod-shaped tools T with various tip shapes can be used, and in any case, the distance d between the rod-shaped tool T and the support base 2 is controlled to be less than or equal to the thickness t0 of the metal plate W.

[0026] Furthermore, in the sequential forming method, when controlling the above-mentioned interval d, a more preferred embodiment is to set the yield stress or 0.2% proof stress of the metal plate W to Ys(N / mm²). 2 ), Young's modulus is E(N / mm 2 ), and when the plate thickness is t0 (mm), the forming angle θ is θ <arctan(40×Ys / (E×t0 3 When forming the area that is )), the distance d between the rod-shaped tool T and the support base 2 is controlled to be less than or equal to the thickness t0 of the metal plate W.

[0027] As mentioned earlier, when the metal plate W is gradually shaped by repeatedly moving the rod-shaped tool T along its circumferential path and feeding it at a pitch, the proportion of elastic deformation among the deformations applied by the rod-shaped tool T increases depending on the material of the metal plate W and the shaping angle θ.

[0028] Figure 8(A) shows the deformation of a metal plate W when the forming angle θ is 10 degrees. The rod-shaped tool T moves along the circular path at the position shown by the solid line, and then the feed amount L 10 The metal plate W is then fed by a pitch mechanism and moves along the next circular path at the position indicated by the dotted line. At this time, the metal plate W is subjected to a displacement Pz corresponding to the amount of indentation in the Z direction by the rod-shaped tool T, as shown in Figure 8(B). In other words, the metal plate W is displaced from the white area to the gray area. Subsequently, springback occurs in the metal plate W as shown in Figure 8(C), but when the forming angle θ is 10 degrees, the amount of springback is small, so the final deformation amount (plastic deformation amount) Pz' becomes large, and the difference between the indentation amount (Pz) of the rod-shaped tool T and the final deformation amount (plastic deformation amount) Pz' becomes small.

[0029] Figure 9(A) shows the deformation of the metal plate W when the forming angle θ is 5 degrees. The rod-shaped tool T moves along the circular path at the position shown by the solid line, as in Figure 8, then is pitch-feeded at a feed rate L5, and moves along the next circular path at the position shown by the dotted line. At this time, the metal plate W is given a displacement Pz corresponding to the amount of indentation by the rod-shaped tool T, as shown in Figure 9(B). However, when the forming angle θ is 5 degrees, the amount of springback is large, as shown in Figure 9(C), so the final deformation amount (plastic deformation amount) Pz' becomes small, and the difference between the amount of indentation (Pz) of the rod-shaped tool T and the final deformation amount Pz' becomes large.

[0030] In a sequential forming method, whether or not the metal sheet W can be given the desired final deformation amount (plastic deformation amount) Pz' depends on the Young's modulus E, yield stress or 0.2% proof stress Ys, and sheet thickness t0 of the metal sheet W. In other words, if the Young's modulus E is small, or if the yield stress or 0.2% proof stress Ys or sheet thickness t0 is large, plastic deformation becomes more difficult even when the same displacement is applied. Based on experimental results of these relationships, the forming angle θ is θ <arctan(40×Ys / (E×t0 3 It was found that under the conditions of ), a sufficient final deformation (plastic deformation) Pz' could not be given to the metal plate W.

[0031] Therefore, in the sequential molding method described above, as previously stated, the molding angle θ is θ <arctan(40×Ys / (E×t0 3 When forming the area where )) is achieved, the distance d between the rod-shaped tool T and the support base 2 is controlled to be less than or equal to the thickness t0 of the metal plate W, thereby providing the metal plate W with a sufficient final deformation (plastic deformation) Pz'. The distance d between the rod-shaped tool T and the support base 2 can be controlled by adjusting the displacement amount in the Z-axis direction of at least one of the rod-shaped tool T and the support base 2.

[0032] Furthermore, in the sequential forming method, when the forming angle θ is within the above range, a more preferred embodiment involves controlling the distance d between the rod-shaped tool T and the support base 2 within the range of 0.9t0 ≤ d ≤ 0.95t0. This is because, when sequential forming was experimentally performed with varying distance d, it was found that the forming accuracy was good when the thickness t0 of the metal plate W was in the range of 0.9t0 to 0.95t0. It was also found that narrowing the distance d in the compression direction beyond 0.9t0 is undesirable, as setting the distance d to less than 0.9t0 causes the metal plate W to move laterally, resulting in wrinkle-like patterns.

[0033] As described above, the sequential molding method and sequential molding apparatus described in the above embodiment, by using a support base 2 that can accommodate various shapes of molded products, can reduce equipment costs and manufacturing costs, while also reducing the difference in distortion between the front and back surfaces of the metal plate W at the contact portion of the rod-shaped tool T, thereby improving the shape accuracy of the molded product and obtaining a high-quality molded product without tool marks.

[0034] Furthermore, the above sequential forming method controls the distance d between the rod-shaped tool T and the support base 2 within a range less than or equal to the thickness t0 of the metal plate W, according to the magnitude of the forming angle θ, and preferably, the forming angle θ is θ <arctan(40×Ys / (E×t0 3 When forming the area where )) is the case, the distance d between the rod-shaped tool T and the support base 2 is controlled to be less than or equal to the thickness t0 of the metal plate W, and more preferably the distance d between the rod-shaped tool T and the support base 2 is controlled to be within the range of 0.9t0 ≤ d ≤ 0.95t0.

[0035] As a result, the above sequential molding method can produce molded products with high shape accuracy while maintaining good surface quality, and can manufacture high-quality molded products even if the metal sheet W is made of a low Young's modulus material such as aluminum.

[0036] Furthermore, the above sequential molding method employs a support base 2 that can move in the three axes of X, Y, and Z, which allows the support base 2 to be made to the minimum necessary size, thereby reducing the labor required for the drive mechanism.

[0037] Furthermore, the above sequential forming method uses a support base 2 having a plane 2S with a size equivalent to the axial projected area of ​​the rod-shaped tool T, and a chamfered portion R around it. This not only enables miniaturization of the support base 2 and labor savings for the drive mechanism, but also facilitates the movement of the support base 2 in the X and Y directions, preventing damage to the metal plate W.

[0038] <Second Embodiment> Figure 10 shows a sequential molding apparatus applicable to a second embodiment of the sequential molding method according to the present invention. In the second embodiment, the same reference numerals are used for components equivalent to those in the first embodiment, and detailed descriptions are omitted.

[0039] In the illustrated example of a sequential molding apparatus, the support base 12 has a flat surface 12S of the same size as the molding area of ​​the metal plate W, and is driven by a support base drive device 15. In this case, the support base drive device 15 is equipped with a lifter 15B and drives the support base 12 only in the Z direction, moving it forward and backward relative to the metal plate W. Similar to the previous embodiment, this support base 12 only needs to have a flat surface 12S, regardless of the various shapes of the molded product.

[0040] In the sequential forming method using the support base 12 described above, the metal plate W is formed by sandwiching the metal plate W between the rod-shaped tool T and the support base 12, and allowing the support base 12 to follow the movement of the rod-shaped tool T. In other words, in the sequential forming method described above, while the rod-shaped tool T is moving in the horizontal X and Y directions, the support base 12 is in contact with the entire area of ​​the metal plate W to be formed, so there is no need to drive the support base 12.

[0041] In the sequential forming method described above, as shown in Figure 11, the support base 12 is lowered while sandwiching the metal plate W between itself and the rod-shaped tool T as the rod-shaped tool T descends in the Z direction. Also, in this embodiment of the sequential forming method, similar to the first embodiment, the distance d between the rod-shaped tool T and the support base 12 is controlled according to the forming angle θ.

[0042] The sequential molding method and sequential molding apparatus of the above embodiment, similar to the first embodiment, use a support base 12 that can accommodate various shapes of molded products, thereby reducing equipment and manufacturing costs while minimizing the difference in distortion between the front and back surfaces of the metal plate W at the contact portion of the rod-shaped tool T, thereby improving the shape accuracy and quality of the molded product. Furthermore, the above sequential molding method and sequential molding apparatus employ a support base 12 having a flat surface 12S of the same size as the molding area of ​​the metal plate W, so the support base 12 only needs to be driven in the forward / backward direction (Z direction) relative to the metal plate W. This allows for simplification of the structure of the support base drive device 15 and simplification of the control program of the device 15.

[0043] The sequential molding method and sequential molding apparatus according to the present invention are not limited to the above embodiments in terms of their structure, and can be modified as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0044] 1. Clamping device 2,12 Receiving stand 2S, 12S Plane (Plane of the support base) 3. Control device 4. Tool drive device 5.15 Support stand drive device R chamfered section T bar tool W Metal plate

Claims

1. In a sequential forming method for shaping a metal plate into a three-dimensional form by pressing the tip of a rod-shaped tool against one main surface of the metal plate, which is held around its periphery, and moving it, Using one support base positioned on the other main surface side of the aforementioned metal plate, The support base has a flat surface facing the tip surface of the rod-shaped tool and having a size equivalent to the molding area of ​​the metal plate, and is movable in three mutually orthogonal directions: X, Y, and Z, with the direction of advancement and retraction relative to the metal plate being the Z-axis direction. A sequential forming method characterized by forming the metal plate by sandwiching the metal plate between the rod-shaped tool and the support base, and allowing the support base to follow the movement of the rod-shaped tool in the three axial directions.

2. The angle between the main surface of the metal plate before forming and the formed inclined surface is defined as the forming angle θ. The sequential molding method according to claim 1, characterized in that the distance d between the rod-shaped tool and the support base is controlled within a range less than or equal to the thickness of the metal plate, according to the magnitude of the molding angle θ.

3. Ys(N / mm²) is the yield stress or 0.2% proof stress of the aforementioned metal plate. ２ ), Young's modulus E (N / mm) ２ ), and the plate thickness t ０ When (mm), The molding angle θ is θ < arctan(40 × Ys / (E × t) ０ ３ When forming the area that is )), the distance d between the rod-shaped tool and the support base is the thickness t of the metal plate. ０ The sequential molding method according to claim 2, characterized in that it is controlled to be as follows.

4. The distance d between the rod-shaped tool and the support base is 0.9t ０ ≤d ≤0.95t ０ The sequential molding method according to claim 3, characterized by controlling within a range.

5. The sequential molding method according to claim 1, characterized in that the support base has a plane having a size equivalent to the projected area in the axial direction of the rod-shaped tool, and has a chamfered portion around the plane.

6. Apparatus for use in the sequential molding method described in claim 1, A clamping device that holds the periphery of the metal plate, The rod-shaped tool is positioned on one main surface side of the metal plate, The support base is positioned on the other main surface side of the metal plate, A sequential molding apparatus characterized by comprising a control device that controls the position of the support base based on pre-set movement path data of the rod-shaped tool.

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