Title of the invention: A method for manufacturing a blank material, a method for manufacturing a press-molded product, a shape determination method, a shape determination program, a blank material manufacturing apparatus, and a blank material.
Technical field
[0001]
The present invention is a punching shear device with shear angle on a metal plate such as iron, aluminum, titanium, magnesium and alloys used in automobiles, home appliances, building structures, ships, bridges, construction machinery, various plants, penstock, etc. Regarding the method of manufacturing a blank material and the method of manufacturing a press-molded product, which are punched and then press-formed, a blank material manufacturing method, a shape determination method, a shape determination program, a blank material manufacturing device, and a blank material. Regarding.
Background technology
[0002]
On a metal plate (hereinafter referred to as a work material 1) of an automobile, a home electric appliance, a building structure, etc., after the work material 1 is placed on a punching die (also referred to as a die) 3 as shown in FIG. By pushing the punching punch 2 (also referred to as a punch) in the direction of the arrow shown in FIG. 1, the punching process for punching the workpiece 1 is often performed.
[0003]
As shown in FIG. 2, the punched surface 8 of the work material 1 after the punching process has a sagging 4 formed by the work material 1 being entirely pushed by the punching punch 2 and a punching punch. The work material 1 is drawn into the clearance between 2 and the punching die 3 (hereinafter, when the term “clearance” is used unless otherwise specified, it means the clearance between the punch and the die) and is formed by being locally stretched. It is composed of a shear surface 5, a fracture surface 6 formed by breaking the workpiece 1 drawn into the clearance between the punching punch 2 and the punching die 3, and a burr 7 generated on the back surface of the workpiece 1. ..
[0004]
Normally, during this punching process, the width of the workpiece 1 as shown in FIG. 3 is to reduce the punching load required for punching the workpiece 1 and the noise generated during the punching of the workpiece 1. A punching punch having an upper blade 10 (inclined blade in the case of FIG. 3) inclined with respect to a direction, that is, a cutting line direction (also referred to as a punching direction) of the work material 1 on its bottom surface is used. In this punching punch 2, since the upper blade 10 is inclined in the cutting line direction, a punching load is locally applied to the workpiece 1, and the workpiece 1 is located from one end side to the other end in the width direction. It is possible to cut sequentially over the sides, which reduces the punching load.
[0005]
However, when such an inclined blade 10 is used for a punching punch 2 having a flat bottom surface, the stretch flangeability is inferior to that of the workpiece 1 punched by the punching punch 2 having a flat bottom surface. This is because the work material 1 is sequentially cut in the width direction by the inclined blade 10, so that the work material 1 bends in the width direction and the work material 1 is excessively curved in the longitudinal direction at the time of punching. It is considered that this is because the work hardening of the punching surface 8 and the roughness of the end face properties are larger than those of the punching punch 2 having a flat blade having a flat bottom surface.
[0006]
Patent Documents 1 and 2 describe that in punching shearing with a punching punch having a tilted blade on the bottom surface, which can reduce punching load and noise, the elongation is equal to or higher than that when a punching punch having a flat blade on the bottom surface is used. A punching shear device with a shear angle that can ensure flangeability is disclosed.
[0007]
Specifically, Patent Document 1 describes a work material after cutting a part of the work material in a punching device with a shear angle having a punch having an upper blade inclined with respect to the cutting direction and a die having a lower blade. The partial plate reverse presser is provided at the position facing the punch, and the partial plate reverse presser has a shear angle, which is an inclined partial plate reverse presser whose inclination angle in the cutting line direction is the same as the inclination angle in the cutting direction of the punch. The punching device is disclosed.
[0008]
As shown in FIG. 4, Patent Document 2 has a punch having a horizontal portion partially in the cutting line direction and a portion excluding the horizontal portion having an upper blade formed of an inclined portion, and a die having a lower blade. Provided are disclosed a punching shear device with a shear angle in which the horizontal portion of the upper blade is arranged above a part or all of the planned extension flange portion in the molding after cutting the workpiece.
[0009]
Patent Document 3 discloses a punching method for punching a work material by using a punch and a die having a recess formed in a concave shape in a cross section parallel to the punching direction by using a linear or curved shear angle at the cutting edge. ing.
[0010]
In Patent Document 4, a welded portion and a work material having a heat-affected zone around the welded portion are provided with a flat portion and a punch having a flat portion and a protruding portion protruding toward the workpiece side from the flat portion. Prior to cutting the work material, the work material is positioned with respect to the punch at a position where shearing of at least one of the heat-affected zone or the welded part by the protrusion is started, and the punch and the die are relative to each other in this positioning state. It discloses a method of moving and shearing and cutting across a weld in a workpiece.
Prior art literature
Patent documents
[0011]
Patent Document 1: Japanese Patent No. 5042935
Patent Document 2: Japanese Patent No. 5042936
Patent Document 3: Japanese Unexamined Patent Publication No. 2010-36195
Patent Document 4: International Publication No. 2017/0574666
Outline of the invention
Problems to be solved by the invention
[0012]
According to the methods of Patent Documents 1 to 4, in the punching shearing process by the punching punch having the inclined blade on the bottom surface, the elongation flange property equal to or higher than that in the case of using the punching punch having the flat blade on the bottom surface is ensured. can do.
[0013]
However, as a result of the study by the present inventors, it was found that if the stretch flangeability is lowered during a large number of processes, it may become unstable.
[0014]
The present invention has been made in view of the above-mentioned problems, and in punching shearing with a punching punch having an inclined blade on the bottom surface, which can reduce a punching load and noise, a punching punch having a flat blade on the bottom surface. It is an object of the present invention to provide a punching method, a method for manufacturing a press-molded product, a blade shape determination program, and a shear angle optimization method, which can stably secure stretch flangeability equal to or higher than that in the case of using.
Means to solve problems
[0015]
As a result of diligent studies by the present inventors, it was found that the shape of the shear angle has an effect on the decrease and variation in the stretch flangeability. The shape of the shear angle where good stretch flangeability is obtained and the shape of the shear angle where the stretch flangeability is reduced or varied are difficult to judge visually, but these should be distinguished in advance. Therefore, it was found that good stretch flangeability can be stably obtained.
[0016]
The present invention has been further studied, and the gist thereof is as follows.
[0017]
(1) A method for producing a blank material by punching a metal plate arranged between the punch and the die by using a punching shear device including a punch having an upper blade and a die having a lower blade. The upper blade is composed of a first inclined portion, a second inclined portion, and a third inclined portion provided in order in the cutting line direction of the metal plate, and the angle of the first inclined portion with respect to the metal plate in the cutting line direction. θ 1, the angle θ 2 of the second inclined portion with respect to the metal plate in the cutting line direction, and the angle θ 3 of the third inclined portion with respect to the metal plate in the cutting line direction are θ 2 ≦ θ 1/2. θ 2 ≦ θ 3/2 is satisfied, and during the punching process, the first inclined portion and the third inclined portion come into contact with the metal plate, and then the second inclined portion comes into contact with the metal plate. A method for manufacturing a blank material.
Here, a set of the position (x n) in the cutting line direction of the shape of the upper blade and the displacement (y n) of the upper blade in the direction away from the metal plate along the moving direction of the punch corresponding to each x n. In the point group (x n, y n) consisting of, the second-order difference quotient J2 n = (y n + 1-2y n + y n-1) / (Δx) 2, the maximum value of the second-order difference quotient J2 max, J3 n = J2 n / | J 2max | is defined, and the first point where the absolute value of J3 n is predetermined and becomes the threshold value δ 2 or more is the boundary position between the first inclined portion and the second inclined portion, and the last. Is the boundary position between the second inclined portion and the third inclined portion, and θ 1, θ 2, and θ 3 are the first inclined portion, the second inclined portion, and the third inclined portion, respectively. The tangent line at any point is the average value of the maximum value and the minimum value of the absolute value of the angle formed with the metal plate.
[0018]
(2) The method for manufacturing a blank material according to (1), wherein the angle θ 2 of the second inclined portion with respect to the metal plate in the cutting line direction satisfies θ 2 ≦ 3.0 °.
[0019]
(3) The above (1) or (1) or (which includes a step of determining the shape of the upper blade before the punching process and including a step of adjusting the shear angle of the upper blade based on the determination result of the shape of the upper blade. 2) Method for manufacturing a blank material.
[0020]
(4) A method for manufacturing a press-molded product, which comprises performing press molding on a blank material obtained by the method for manufacturing a blank material according to any one of (1) to (3) above to obtain a press-molded product.
[0021]
(5) A method for determining the shape of the upper blade used in the method for manufacturing a blank material according to the above (3), which corresponds to the position (x n) in the cutting line direction of the shape of the upper blade and each x n. A step for inputting a point group (x n, y n) consisting of a set of displacements (yn) of the upper blade in a direction away from the metal plate along the movement direction of the punch, and an input point group (x n). , Y n), the step of finding the first-order difference quotient J1 n = (y n + 1-y n) / Δx, and the second-order difference quotient J2 n = (y n + 1-2y n + y n-1). / (Δx) 2 is obtained, the maximum value J2 max of the second-order difference quotient is obtained, the type determination value J3 n = J2 n / | J 2 max | is obtained, and the second inclined portion and the above are described. At the boundary of the first inclined portion, one or both of the boundary between the second inclined portion and the third inclined portion, the absolute value of J3 n is a predetermined threshold value δ 2 or more, and J3 n is positive. A shape determination method comprising a step of determining that it is necessary to adjust the shear angle of the upper blade in the case.
[0022]
(6) A program for determining the shape of the upper blade used in the method for manufacturing a blank material according to the above (3), which corresponds to the position (x n) in the cutting line direction of the shape of the upper blade and each x n. A step for inputting a point group (x n, y n) consisting of a set of displacements (yn) of the upper blade in a direction away from the metal plate along the movement direction of the punch, and an input point group (x n). , Y n), the step of finding the first-order difference quotient J1 n = (y n + 1-y n) / Δx, and the second-order difference quotient J2 n = (y n + 1-2y n + y n-1). / (Δx) 2 is obtained, the maximum value J2 max of the second-order difference quotient is obtained, the type determination value J3 n = J2 n / | J 2 max | is obtained, and the second inclined portion and the above are described. At the boundary of the first inclined portion, one or both of the boundary between the second inclined portion and the third inclined portion, the absolute value of J3 n is a predetermined threshold value δ 2 or more, and J3 n is positive. A shape determination program comprising executing a step of determining that it is necessary to adjust the shear angle of the upper blade in the case.
[0023]
(7) A manufacturing apparatus used in the method for manufacturing a blank material according to the above (3), in which the position of the upper blade in the cutting line direction (x n) and the movement direction of the punch corresponding to each x n. In the input unit for inputting a point group (x n, y n) consisting of a set of displacements (yn) of the upper blade in the direction away from the metal plate, and in the input point group (x n, y n). On the other hand, the first calculation unit for obtaining the first-order difference quotient J1 n = (y n + 1-y n) / Δx and the second-order difference quotient J2 n = (y n + 1-2y n + y n-1) / ( Δx) A second calculation unit for obtaining 2, a third calculation unit for obtaining the maximum value J2 max of the second-order difference quotient, and a fourth calculation unit for obtaining the type determination value J3 n = J2 n / | J 2 max | The absolute value of J3n is predetermined at one or both of the boundary between the second inclined portion and the first inclined portion and the boundary between the second inclined portion and the third inclined portion. , A blank material manufacturing apparatus comprising a determination unit for determining that it is necessary to adjust the shear angle of the upper blade when the threshold value δ 2 or more and J3 n is positive.
[0024]
(8) A blank material having a sheared end face, where the area ratio of the secondary sheared surface in the entire range of the sheared end surface is A2 and the center value of the radius of curvature in the top view of the entire range of the blank line is R, the sheared end surface. It is a region A having a width of 5 mm surrounded by two perpendicular lines drawn in the plate thickness direction, and the area ratio of the secondary shear plane in the region A is A 2/2 or less, and the upper surface of the region A. A blank material characterized in that a region A having a radius of curvature of 1/2 or less of R exists.
[0025]
(9) The blank material according to (8), wherein the area ratio of the sheared surface in the region A is 80% or less of the area ratio of the sheared surface in the region excluding the region A from the entire range of the sheared end face.
[0026]
(10) The blank material according to (8) or (9), wherein the change in the area ratio of the sheared surface in the plate width direction of the region A is within ± 20%.
The invention's effect
[0027]
According to the present invention, in punching shearing with a punching punch having a tilted blade on the bottom surface, which can reduce the punching load and noise, the elongation flange property is equal to or higher than that when a punching punch having a flat blade on the bottom surface is used. Can be stably secured.
A brief description of the drawing
[0028]
[Fig. 1] Fig. 1 is a diagram schematically showing a punching process.
FIG. 2 is a diagram schematically showing the characteristics of the punched surface 8.
3A and 3B are views schematically showing a conventional punching process with an inclined blade, in which FIG. 3A is a front elevation view thereof, FIG. 3B is a side view thereof, and AA in FIG. 3A. It is a line sectional view.
[Fig. 4] Fig. 4 is a diagram schematically showing a punching shear device to which an inclined blade having a horizontal portion partially in the cutting line direction is applied, in which (a) is a front elevation view thereof and (b) is a front view thereof. It is a side view, and is a sectional view taken along the line BB in (a).
FIG. 5 is a diagram showing the shape of a punch with a shear angle used in the study of the present invention.
6A and 6B are views showing the configuration of a punching die for a drum-shaped stretch flange test used in the study of the present invention, where FIG. 6A is a perspective view, FIG. 6B is a front view, and FIG. 6C is a side view.
FIG. 7 is a diagram showing the shape of the punched portion used in the study of the present invention.
[Fig. 8] Fig. 8 is a diagram showing the results of investigating the fracture limit strain of a sample punched using punches with shear angles having different shapes.
[Fig. 9] Fig. 9 is a diagram schematically showing an example of an stretched flange portion, in which (a) is a blank (work material) before flange-up molding, and (b) is a member after flange-up molding. It is a figure which shows.
[Fig. 10] Fig. 10 is a diagram showing the shape of a punch including horizontal portions at both ends of the upper blade.
FIG. 11 is a flowchart for determining a punch shape type from the punch two-dimensional shape data in the present invention.
FIG. 12 is an example of determining a punch shape type from the punch two-dimensional shape data in the present invention.
FIG. 13 is another example in which the shape type of a punch is determined from the two-dimensional shape data of the punch in the present invention.
FIG. 14 is another example of determining the shape type of a punch from the two-dimensional shape data of the punch in the present invention.
FIG. 15 is another example of determining the shape type of a punch from the two-dimensional shape data of the punch in the present invention.
FIG. 16 is another example of determining the shape type of a punch from the two-dimensional shape data of the punch in the present invention.
FIG. 17 is a diagram illustrating a shear plane of a blank obtained by the present invention.
Embodiment for carrying out the invention
[0029]
First, the contents of the study conducted by the present inventors that led to the completion of the present invention will be described.
[0030]
The present inventors diligently examined the relationship between the shapes of the four patterns of punches shown in FIG. 5 and the stretch flangeability of the punched surface 8 for the work material 1 punched by the punching punch 2.
[0031]
FIG. 5 shows the shape of the punch from the front view, and FIGS. 5A to 5C are inclined blades having a first inclined portion, a second inclined portion, and a third inclined portion in the cutting line direction. The first inclined portion has an angle θ 1 with respect to the metal plate in the cutting line direction, the second inclined portion has an angle θ 2 with respect to the metal plate in the cutting line direction, and the third inclined portion has a metal in the cutting line direction. It forms an angle θ 3 with respect to the plate.
[0032]
Here, from the set of the position in the cutting line direction (x n) of the shape of the upper blade and the displacement (y n) of the upper blade in the direction away from the metal plate along the moving direction of the punch corresponding to each x n. In the point group (x n, y n), the second-order difference quotient J2 n = (y n + 1-2y n + y n-1) / (Δx) 2, the maximum value of the second-order difference quotient J2 max, J3 n = J2 n / | J 2max | is defined, and the first point where the absolute value of J3 n is predetermined and the threshold value δ 2 or more is the boundary position between the first inclined portion and the second inclined portion, and the last point is. This is the boundary position between the second inclined portion and the third inclined portion.
[0033]
Further, θ 1, θ 2, and θ 3 are the maximum values ​​of the absolute values ​​of the angles formed by the tangents at any points of the first inclined portion, the second inclined portion, and the third inclined portion with the metal plate, respectively. It is the average value of the minimum values. In the example of FIG. 5, the first inclined portion, the second inclined portion, and the third inclined portion have a shape that becomes a straight line in the cutting line direction, and an arbitrary tangent line in the cutting line direction forms an angle with the metal plate in each inclined portion. Is constant. Further, in the example of FIG. 5, θ 1 = θ 3 and θ 2 = 0.0 °.
[0034]
(A) is a shape in which a horizontal portion is provided at the R shear angle and the reverse shear angle, and the shear angle first penetrates into the workpiece and the central horizontal portion finally penetrates (hereinafter, “TYPE”). -A "). (B) is a shape in which a horizontal portion is provided in a part of the shear angle inclined in one direction, and one of the shear angles first penetrates the workpiece, then the central portion, and finally the other shear. The shape is such that the corners penetrate into the work piece (hereinafter referred to as "TYPE-B"). (C) is a shape in which a horizontal portion is provided at the roof shear angle, and the central horizontal portion first penetrates the workpiece and finally the shear angle (hereinafter referred to as "TYPE-C"). ). (D) is a flat blade having no inclined portion (hereinafter referred to as "TYPE-1").
[0035]
For TYPE-A, TYPE-B, and TYPE-C, four types of punches with different horizontal widths and shear angles were prepared.
[0036]
Punches of these shapes were punched using the punching die for drum-shaped stretch flange test shown in FIG. As shown in FIG. 7, the blank line was common at R30 mm and the opening angle θ120 ° in the top view, only the punch was replaced, and the shear angle and the pattern of the horizontal portion were changed. At the time of punching, the center position of the second inclined portion of the punch in the cutting line direction is arranged so as to correspond to the center position of the blank line.
[0037]
The 13 types of drum-shaped test punches shown in Table 1 were prepared and punched with a 60-ton crank press machine. The test material was JSC980Y with a thickness of 1.4 mm, and the punching clearance was constant at 12.6% of the plate thickness of the work material.
[0038]
A side bend test was carried out on the sample after punching to investigate the fracture limit strain. Table 1 shows the results of two tests for each sample.
[0039]
[table 1]

[0040]
FIG. 8 illustrates the results of Table 1. Group 1 shows the test results for TYPE-A-1, TYPE-B-1, and TYPE-C-1 in Table 1, and Group 2 shows TYPE-A-2, TYPE-B-2, and TYPE- in Table 1. The test results for C-2, Group 3 shows the results of the tests for TYPE-A-3, TYPE-B-3, and TYPE-C-3 in Table 1, and Group 4 shows the TYPE-A-4 in Table 1. , TYPE-B-4, TYPE-C-4. "Xx-y" on the horizontal axis of the graph (X is any of A, B, C, x, y is a numerical value) means the y-th test result of TYPE-X-x. The horizontal lines in the graph are the average values ​​of TYPE-1, and the bars are the results of two tests for each of the four types of samples, TYPE-A, TYPE-B, and TYPE-C. The vertical axis of the graph is the breaking limit strain.
[0041]
A specific method of the side bend test is disclosed in Japanese Patent Application Laid-Open No. 2009-145138.
[0042]
Specifically, the side bend test device has a pair of arms rotatably attached to fulcrums at different positions, and a ruled line or a marked point is marked on the upper surface or the lower surface at the tip of the arm. It has a pair of grips that fix the upper and lower surfaces of both ends of the test piece together with the arms, and a load applying means that applies a load to the rear ends of the pair of arms, and the pair of arms is a leg. The parts are configured to intersect each other. Then, a load is applied to the rear end by the load applying means, and the tips of the pair of arms move in opposite directions and separate from each other with the fulcrum as the center, whereby the arm and the grip are fixed. It has a function of imparting tensile and bending deformation to the end face in the plate thickness direction at the central portion in the longitudinal direction of the test piece.
[0043]
Then, using a side bend test device, the upper and lower surfaces of both ends of the test piece marked with a ruled line or a reference point on the upper surface or the lower surface are formed by the arm portion and the grip portion at the tips of the pair of arms, respectively. After fixing, a load is applied to the rear ends of the pair of arms by the load applying means to apply tension and bending deformation so that the end face in the plate thickness direction at the central portion in the longitudinal direction of the test piece is widened, and the storage means. Based on the image observed by the first observing means memorized by the second observing means, the strain when the crack penetrated in the plate thickness direction of the end face of the test piece observed by the first observing means was observed by the second observing means. Calculated based on borders or gauge points.
[0044]
As can be seen from FIG. 8, it was confirmed that in the case of the TYPE-C shape, the breaking strain may be smaller than that in the case of using the flat blade, that is, the stretch flangeability may be lowered. As can be seen from this result, TYPE-C, that is, the upper blade has the shape of (c), and punches are made in advance so that the horizontal portion of the upper blade is not punched by the punch that first penetrates the work material. By checking the shape of the upper blade, it is possible to avoid deterioration of the stretch flangeability.
[0045]
In other words, by using a punch such as TYPE-A and TYPE-B in which the inclined portion first penetrates into the work material, it is possible to avoid deterioration of the stretch flangeability. The inclined portion that first penetrates the work material may be an inclined portion on both sides of the horizontal portion as in TYPE-A, or only an inclined portion on one side of the horizontal portion as in TYPE-B. You may.
[0046]
The cause of the decrease in stretch flangeability in TYPE-C is considered as follows.
[0047]
When flange-up molding is performed on the workpiece 1 having the shape as shown in FIG. 9 (a) by punching and the planned stretch flange portion 22 is used as the stretch flange portion 21, the punched surface 8 (cut surface) is used. Tensile stress is applied to. The tensile stress is greatest at the center of the stretch flange portion 21.
[0048]
When the upper blade of the punch has a TYPE-C shape, only the horizontal part of the upper blade penetrates near the center of the planned extension flange at the beginning of punching. At this time, since the horizontal portion of the upper blade does not have the effect of reducing the load due to the shear angle, it reaches a situation where it cannot easily penetrate into the workpiece, the formation of the fracture surface is delayed, and the shear surface ratio increases. As a result, the work hardening of the work material becomes large. Since this portion is the portion to which the tensile stress is most applied during the flange-up molding, the stretch flangeability is deteriorated.
[0049]
Further, the same punching process was performed using punches in which the length W of the second inclined portion and the angles θ 1, θ 2, and θ 3 of the first, second, and third inclined portions were changed, and the sample after punching was performed. The rupture limit strain was investigated. The results are shown in Tables 2 and 3.
[0050]
[Table 2]

[0051]
[Table 3]

[0052]
From the above results, it can be seen that when the length W of the second inclined portion is W = 3.0 mm, the effect of improving the breaking limit strain is small, and it is preferable that W ≧ 5.0 mm is satisfied. Also, the angle of the first and third inclined portions However, it can be seen that the effect can be obtained even when θ 1 = θ 3 = 5.0 °, but the effect is small when θ 1 = θ 3 = 0.1 °. Further, it can be seen that the angle of the second inclined portion preferably satisfies θ 2 ≦ 1.0 °. Further, when the difference between the angle of the first (third) inclined portion and the angle of the second inclined portion is small, the effect is small, and it is preferable that θ 2 ≦ θ 1/2 (θ 2 ≦ θ 3/2) is satisfied. I understand.
[0053]
As can be seen from Table 2, when W = 5.0 mm, TYPE-A has a larger breaking limit strain than TYPE-B. In the case of TYPE-A, the horizontal portion is cut with the inclined portions on both sides already cut off, while in the case of TYPE-B, the horizontal portion is cut with one inclined portion remaining. As a result, it is considered that there is a difference in the range of W that can secure high stretch flangeability. That is, it can be seen that TYPE-A can secure high stretch flangeability in a wide range as compared with TYPE-B and is superior to TYPE-B.
[0054]
Further, the same test was performed using punches including horizontal portions at both ends of the upper blade shown in FIG. As a result of two tests, the breaking limit strains were 0.22 and 0.21, and the effect of improving the breaking limit strain was not observed. It is considered that this is because the horizontal portion, which does not have the load reduction effect due to the shear angle, first invades the work material.
[0055]
Next, each step of the method of determining the shape of the upper blade of such a punch will be described.
[0056]
As illustrated above, the shape of the upper blade of the punch has a horizontal portion width of several tens of mm and a shear angle of about 1.0 °, so it is extremely difficult to visually determine the shape. Therefore, the shape of the upper blade is measured using a laser displacement meter, a contact-type three-dimensional shape measuring device, or the like. However, according to the present invention, the shape measurement data is used to measure the shape of the upper blade. It is easily determined whether or not the shape of the blade is suitable for punching.
[0057]
First, input the 2D data of the upper blade with an inclined punch measured by a laser displacement meter or a contact type 3D shape measuring device. The two-dimensional data is a point cloud (x n) consisting of k sets of evenly spaced cutting line direction positions (x n) and the displacement of the upper blade (y n) in the movement direction of the punch corresponding to each x n. n, y n) (n = 1 to k). y n is the displacement that is the smallest at the position where it first penetrates into the work piece and becomes larger as it moves away, and the position in the moving direction of the punch where y n = 0 may be arbitrarily set.
[0058]
Next, for the point cloud (x n, y n) (n = 2 to k-1), the first-order difference quotient J1 n = (y n + 1-y n) / Δx is obtained.
[0059]
If the absolute value | J1 n | of the first-order difference quotient J1 n is larger than the predetermined threshold value δ 1 of the horizontal part determination, it can be seen that the upper blade between the nth to n + 1st points of the point cloud is tilted. .. The threshold value δ 1 can be, for example, 0.1. Subsequently, the second-order difference quotient J2 n = (y n + 1-2y n + y n-1) / (Δx) 2 is obtained. Further, the maximum value J2 max of the second-order difference quotient is obtained. The maximum value J2 max of the second-order difference quotient is the second-order difference quotient (y 3-2 y 2 + y 1) / (Δx) 2 of the point cloud (x, y) obtained by changing n to (y k-2 y k). -1 + y k-2) / (Δx) The maximum value up to 2.
[0060]
Subsequently, the type determination value J3 n = J2 n / | J2 max | is obtained. When the absolute value of J3 n is larger than the threshold value δ 2 of the type determination, the nth point corresponds to the position where the shape of the upper blade changes. The threshold value δ 2 is a value of 1 or less and can be arbitrarily set as needed. For example, δ 2 = 0.5 can be set.
[0061]
At this time, if the sign of J3 n is negative, the inclined portion has a shape inclined downward with respect to the horizontal portion (direction closer to the workpiece), and if the sign of J3 n is positive, the inclined portion has a shape. When the shape is inclined upward (in the direction close to the workpiece) with respect to the horizontal portion, the inclined direction of the inclined portion can be determined by the reference numeral of J3n.
[0062]
As described above, the shape used in the present invention is the shape of TYPE-A as shown in FIG. 5A. That is, at one or both of the boundary between the second inclined portion and the first inclined portion and the boundary between the second inclined portion and the third inclined portion, the absolute value of J3 n is equal to or more than the predetermined threshold value δ 2 and J3. If n is positive, it is necessary to adjust the shear angle of the upper blade.
[0063]
The flowchart of this determination is shown in FIG. The shape of the punch is determined by causing a computer or the like to execute an upper blade shape determination program that performs such processing. Specific determination examples are shown in FIGS. 12 to 16.
[0064]
FIG. 12 (a) shows the punch shapes (x, y) and J1 n, and FIG. 12 (b) shows the punch shapes (x, y) and J3 n. In this example, the absolute value of J3 n is larger than δ 2 and the sign of J3 n is negative at both ends of the horizontal portion (| J1 n | <δ 1) (| J3 n | <δ 2, J3 n < 0) There is a point. In this case, the shape of the punch is determined to be TYPE-A.
[0065]
In the examples of FIGS. 13 and 14, the absolute value of J3 n is larger than δ 2 and the sign of J3 n is negative at one end of the horizontal portion (| J1 n | <δ 1) (| J3 n | <δ 1). 2. There is a point J3 n <0), the absolute value of J3 n is larger than δ 2 at the other end, and the sign of J3 n is positive (| J3 n | <δ 2, J3 n> 0). exist. In this case, the shape of the punch is determined to be TYPE-B.
[0066]
In the example of FIG. 15, the absolute value of J3 n is larger than δ 2 and the sign of J3 n is positive at both ends of the horizontal portion (| J1 n | <δ 1) (| J3 n | <δ 2, J3). n> 0) There is a point. In this case, the shape of the punch is determined to be TYPE-C.
[0067]
The example of FIG. 16 is a pattern in which TYPE-A, TYPE-B, and TYPE-C are mixed. When the punch has such a shape, it is conceivable to use it so that the shape of TYPE-B and TYPE-C does not hit the planned extension flange where the end face property of the punched surface is the most problematic, but the processing is stable. It is preferable not to use it in consideration of sex.
[0068]
In the determination method of the present invention, the value of J3 n is stable with respect to the change of the value of Δx, and the absolute values ​​of J1 n and J2 n do not need to be highly accurate. That is, in the punch shape determination by this algorithm, it is not necessary to carefully examine Δx and examine the influence on J1 n and J2 n in advance, and it is possible to easily determine the punch shape without considering the measurement accuracy. can.
[0069]
The punch determined to be TYPE-B or TYPE-C cannot be used as it is, but if the shear angle is optimized by processing the upper blade and adjusted to the shape of TYPE-A, TYPE- It can be used in the same way as the punch determined to be A. For the upper blade after processing, the shape is determined again by using the above determination method.
[0070]
Each component of the punching shear device 15 with a shear angle used in the present invention will be described.
[0071]
As shown in FIG. 4, the punching shear device 15 with a shear angle includes at least a punching punch 2, a punching die 3, and a holding plate 9. The punching punch 2 is provided with an upper blade 10 on the bottom surface thereof, and the upper blade 10 has a first inclined portion 12a, a second inclined portion 11, and a third inclined portion 12c in the width direction. In FIG. 4, the second inclined portion is parallel to the cutting line direction.
[0072]
The first inclined portion 12a and the third inclined portion 12b function as so-called shear angles. In the present invention, as described above, the shapes of the first inclined portion 12a and the third inclined portion 12b are first covered by both ends (first inclined portion and third inclined portion) as shown in FIG. 5A. A shape that invades the processed material and finally the central portion (second inclined portion) can be applied, and the shape shown in (b) and (c) is not applied. The punching punch 2 is configured to be operable in the direction P shown in FIG.
[0073]
The punching die 3 has an end portion located in the longitudinal direction of the upper surface thereof functioning as the lower blade 3a, and the upper blade 10 of the punching punch 2 is located above the lower blade 3a. The shapes of the side surface 2b on the lower end side of the punching punch 2 and the side surface 3b on the upper end side of the punching die 3 correspond to each other, and any shape can be provided between the side surface 2b and the side surface 3b. It is configured to provide clearance. The lower blade 3a may be configured to be able to cut an open cross section in order to enable blank processing, or may be configured to be able to cut a closed cross section in order to enable hole processing.
[0074]
A work material 1 is placed on the upper surface of the punching die 3, and the work material 1 placed in this way is sandwiched between the upper surface of the punching die 3 and the lower surface of the pressing plate 9. It will be.
[0075]
The second inclined portion 11 of the upper blade 10 is a part of the work material 1, and the punching punch 2 described above is partially or wholly formed on a part or all of the planned extension flange portion 22 where the end surface property of the punched surface 8 is most problematic. It is preferable to arrange the second inclined portion 11 of the above.
[0076]
Next, a process of punching the workpiece 1 using the punching shear device 15 with a shear angle having such a configuration will be described.
[0077]
First, as shown in FIG. 4, the work material 1 is placed on the punching die 3, and then the work material 1 is sandwiched between the upper surface of the punching die 3 and the lower surface of the pressing plate 9. After that, the punching punch 2 having the upper blade 10 is pushed in from above the workpiece 1 toward the lower side indicated by the direction P. After that, by being sandwiched between the lower blade 3a and the upper blade 10, a shearing force acts on the work material 1, so that the work material 1 is cut and punched into a predetermined shape.
[0078]
Here, since the first inclined portion 12a and the third inclined portion 12b are inclined in the width direction, a punching load is locally applied to the workpiece 1 at the time of punching to cut the workpiece 1. Will be done. Since the punching load is locally applied, the required punching load can be reduced and the noise can be reduced as compared with the punching punch 2 using a flat blade having a flat bottom surface.
[0079]
On the other hand, unlike the first inclined portion 12a and the third inclined portion 12b, the second inclined portion 11 does not locally apply a punching load, but is punched by the second inclined portion 11 having a small inclination. Since the surface 8 is less likely to bend in the width direction, the punched surface 8 becomes uniform and the stretch flangeability is improved. Further, since the work material 1 is punched by the first inclined portion 12a and the third inclined portion 12b over a certain range before being punched by the second inclined portion 11, it is punched by the second inclined portion 11. The range is smaller than that of the punching punch 2 having a flat blade on the entire bottom surface, and as a result, the required punching load can be reduced and the noise can be reduced even when punching by the second inclined portion 11. ..
[0080] [0080]
That is, in the punching punch 2 to which the present invention is applied, the second inclined portion 11 is provided in a part of the upper blade 10, and the first inclined portion 12a and the third inclined portion 12b are provided in the portion other than the second inclined portion 11. As a result, it is possible to reduce the punching load and noise as compared with the punching punch having a flat blade on the entire bottom surface, and further to make the punching surface uniform and improve the stretch flangeability.
[0081]
The length L1 in the width direction (cutting line direction) of the second inclined portion 11 of the upper blade 10 is preferably 10 to 60% of the length L2 in the width direction of the workpiece 1, preferably 20 to 50%. More preferably, 30-40% is even more preferable.
[0082]
When the length L1 of the second inclined portion 11 is shorter than 10% of the length L2 in the width direction of the work material 1, the work material is formed by the first inclined portion 12a and the third inclined portion 12b around the second inclined portion 11. 1 tends to bend in the width direction, non-uniformity of the punched surface 8 and work hardening increase, and it becomes difficult to obtain the effect of the present invention that the stretch flangeability is improved.
[0083]
When the length L1 of the second inclined portion 11 is longer than 60% of the length L2 in the width direction of the workpiece 1.Since the stretch flange processing occurs due to the concentration of strain in the width direction (cutting line direction), it becomes difficult to obtain the effect of the present invention of improving the stretch flange property.
[0084]
However, these values ​​may vary depending on the processing conditions and the material of the material 1 to be processed, and it does not mean that the effect of the present invention cannot be obtained if it exceeds this range in all cases.
[0085]
If the absolute values ​​θ 1 and θ 3 of the angles in the width direction of the first inclined portion 12a and the third inclined portion 12b of the upper blade 10 to which the present invention is applied are in the range of 0.5 to 5.0 °, the first 2 There is almost no effect on the amount of work hardening and the non-uniformity of the fracture surface shape of the portion punched by the inclined portion 11.
[0086]
When the absolute values ​​θ 1 and θ 3 of the angles of the first inclined portion 12a and the third inclined portion 12b exceed 5.0 °, the effect of reducing the press load and reducing the noise becomes large, but the beating with the inclined blade 10 is used. The fracture surface properties (work hardening, non-uniformity of the fracture surface) of the punched surface 8 of the punched portion become worse. Therefore, the absolute values ​​θ 1 and θ 3 of the angles of the first inclined portion 12a and the third inclined portion 12b are preferably 0.5 to 5.0 °. Further, θ 1 and θ 3 may be different from each other as long as they are within the above range.
[0087]
The metal plate used as the work material in the present invention is not particularly limited, and a metal plate such as iron, aluminum, titanium, magnesium, or an alloy thereof can be punched. The plate thickness is not particularly limited, but is suitable for processing a metal plate having a thickness of 0.5 to 4.0 mm. Further, edge cracking in stretch flange forming is likely to occur when a high-strength steel sheet is press-formed to obtain a press-molded product, which is particularly effective for processing a steel sheet having a tensile strength of 590 MPa or more.
[0088]
The blank obtained by the above method has a sheared end face 31 as shown in FIG. The sheared end face includes a sheared surface 32 and a secondary sheared surface 33. The secondary sheared surface 33 may have a divided shape as shown in (a) or a continuous shape as shown in (b).
[0089]
Assuming that the area ratio of the secondary shear surface 33 in the entire range of the shear end surface 31 is A2 and the median value of the radius of curvature in the top view of the entire blank line is R, the shear end surface 31 is in the plate thickness direction in the shear end surface 31. A region A having a width of 5 mm surrounded by two drawn perpendicular lines, the area ratio of the secondary shear surface 33 in the region A is A2 / 2 or less, and the radius of curvature in the top view of the region A is R. There is a region A that is less than or equal to 1/2 of. Here, the radius of curvature of the blank line in the top view is obtained every 1 mm from the end of the blank line. When the blank line is a straight line, the radius of curvature is ∞. The area A in the figure is for explaining the range of the area A.
[0090]
If the secondary shear surface 33 is present on the shear end surface 31 of the blank, the stretch-flange property of the blank tends to decrease, and if the ratio of the secondary shear surface 33 is large, the decrease becomes remarkable. If the ratio of the secondary sheared surface 33 is low in a region where the radius of curvature of the blank line is small, that is, in a portion where deformation is concentrated, deterioration of the stretch flangeability can be suppressed.
[0091]
Further, the area ratio of the sheared surface 32 in the region A is preferably 80% or less, more preferably 70% or less, still more preferably 60% or less of the area ratio of the sheared end surface 31 excluding the region A.
[0092]
Further, since the stretch flangeability tends to decrease even when the ratio of the sheared surface 32 is non-uniform, it is preferable that the change in the area ratio of the sheared surface 32 in the plate width direction of the region A is within ± 20%. For the change in the area ratio of the sheared surface 32 in the plate width direction of the region A, the area ratio of the sheared surface 32 is obtained every 1 mm from the end of the region A, and the change is obtained. The change in the sheared surface 32 is more preferably within ± 15%, and even more preferably within ± 10%.
[0093]
The width of such a region A is more preferably large, more preferably a width of 7 mm satisfying the above-mentioned conditions, and further preferably a width of 10 mm satisfying the above-mentioned conditions.
Code description
[0094]
1 Work material
2 Punch for punching
3 Punching die
3a lower blade
4 Dare
5 Sheared surface
6 Fracture surface
7 Bali
8 punched surface
9 Holding plate
10 Upper blade
11 Second slope
12a 1st slope
12b 3rd slope
15 Punching shear device
21 Extension flange part
22 Scheduled extension flange
31 Shear end face
32 sheared surface
33 Secondary shear surface
The scope of the claims
[Claim 1]
A method of producing a blank material by punching a metal plate arranged between the punch and the die using a punching shear device including a punch having an upper blade and a die having a lower blade.
The upper blade is composed of a first inclined portion, a second inclined portion, and a third inclined portion provided in order in the cutting line direction of the metal plate.
The angle θ 1 of the first inclined portion with respect to the metal plate in the cutting line direction, the angle θ 2 of the second inclined portion with respect to the metal plate in the cutting line direction, and the third inclined portion in the cutting line direction. The angle θ 3 with respect to the metal plate is
Θ 2 ≤ θ 1/2,
Θ 2 ≤ θ 3/2
The filling,
During the punching process, the first inclined portion and the third inclined portion come into contact with the metal plate, and then the second inclined portion comes into contact with the metal plate.
A method for manufacturing a blank material.
here,
A point consisting of a set of the position in the cutting line direction (x n) of the shape of the upper blade and the displacement (y n) of the upper blade in the direction away from the metal plate along the moving direction of the punch corresponding to each x n. In the group (x n, y n)
2nd floor difference quotient J2 n = (y n + 1-2y n + y n-1) / (Δx) 2, 2nd floor difference quotient maximum value J2 max,
J3 n = J2 n / | J 2max | is defined, and the first point where the absolute value of J3 n becomes the threshold value δ 2 or more is the boundary position between the first inclined portion and the second inclined portion. The last point is the boundary position between the second inclined portion and the third inclined portion.
θ 1, θ 2, and θ 3 are the maximum values ​​of the absolute values ​​of the angles formed by the tangents at any points of the first inclined portion, the second inclined portion, and the third inclined portion with the metal plate, respectively. The average of the value and the minimum value.
[Claim 2]
The method for manufacturing a blank material according to claim 1, wherein the angle θ 2 of the second inclined portion with respect to the metal plate in the cutting line direction satisfies θ 2 ≦ 3.0 °.
[Claim 3]
The blank according to claim 1 or 2, which includes a step of determining the shape of the upper blade before the punching process and includes a step of adjusting the shear angle of the upper blade based on the determination result of the shape of the upper blade. Material manufacturing method.
[Claim 4]
A method for manufacturing a press-molded product, which comprises performing press molding on a blank material obtained by the method for manufacturing a blank material according to any one of claims 1 to 3 to obtain a press-molded product.
[Claim 5]
A method for determining the shape of the upper blade used in the method for manufacturing a blank material according to claim 3.
A point consisting of a set of the position in the cutting line direction (x n) of the shape of the upper blade and the displacement (y n) of the upper blade in the direction away from the metal plate along the moving direction of the punch corresponding to each x n. Steps to enter the group (x n, y n),
For the input point cloud (x n, y n), the step of finding the first-order difference quotient J1 n = (y n + 1-yn) / Δx,
2nd floor difference quotient J2 n = (y n + 1-2y n + y n-1) / (Δx) 2
The step to find the maximum value J2 max of the second floor difference quotient,
The step to obtain the type judgment value J3 n = J2 n / | J 2max |
At the boundary between the second inclined portion and the first inclined portion, or one or both of the boundary between the second inclined portion and the third inclined portion, the absolute value of J3 n is a predetermined threshold value δ 2 or more. And when J3 n is positive, it is determined that the shear angle of the upper blade needs to be adjusted.
A shape determination method characterized by comprising.
[Claim 6]
A program for determining the shape of the upper blade used in the method for manufacturing a blank material according to claim 3.
A point consisting of a set of the position in the cutting line direction (x n) of the shape of the upper blade and the displacement (y n) of the upper blade in the direction away from the metal plate along the moving direction of the punch corresponding to each x n. Steps to enter the group (x n, y n),
For the input point cloud (x n, y n), the step of finding the first-order difference quotient J1 n = (y n + 1-yn) / Δx,
2nd floor difference quotient J2 n = (y n + 1-2y n + y n-1) / (Δx) 2
The step to find the maximum value J2 max of the second floor difference quotient,
The step to obtain the type judgment value J3 n = J2 n / | J 2max |
At the boundary between the second inclined portion and the first inclined portion, or one or both of the boundary between the second inclined portion and the third inclined portion, the absolute value of J3 n is a predetermined threshold value δ 2 or more. And when J3 n is positive, it is determined that the shear angle of the upper blade needs to be adjusted.
A shape determination program characterized by executing.
[Claim 7]
A manufacturing apparatus used in the method for manufacturing a blank material according to claim 3.
A point consisting of a set of the position in the cutting line direction (x n) of the shape of the upper blade and the displacement (y n) of the upper blade in the direction away from the metal plate along the moving direction of the punch corresponding to each x n. An input unit for inputting a group (x n, y n),
For the input point cloud (x n, y n), the first calculation unit for obtaining the first-order difference quotient J1 n = (y n + 1-yn) / Δx,
Second-order difference quotient J2 n = (y n + 1-2y n + y n-1) / (Δx) 2 and the second calculation unit
The third calculation unit for finding the maximum value J2 max of the second-floor difference quotient,
The 4th calculation unit that obtains the type judgment value J3 n = J2 n / | J 2max |
At the boundary between the second inclined portion and the first inclined portion, or one or both of the boundary between the second inclined portion and the third inclined portion, the absolute value of J3 n is a predetermined threshold value δ 2 or more. And when J3 n is positive, the determination unit that determines that it is necessary to adjust the shear angle of the upper blade.
A blank material manufacturing apparatus characterized by comprising.
[Claim 8]
A blank material with a sheared end face
When the area ratio of the secondary sheared surface in the entire range of the sheared end surface is A2 and the median value of the radius of curvature in the top view of the entire blank line range is R.
A region A having a width of 5 mm surrounded by two perpendicular lines drawn in the plate thickness direction in the shear end face, and the area ratio of the secondary shear plane in the region A is A 2/2 or less, and the region A. There is a region A whose radius of curvature is ½ or less of R in the top view of.
A blank material characterized by that.
[Claim 9]
The blank material according to claim 8, wherein the area ratio of the sheared surface in the region A is 80% or less of the area ratio of the sheared surface in the region excluding the region A from the entire range of the sheared end surface.
[Claim 10]
The blank material according to claim 8 or 9, wherein the change in the area ratio of the sheared surface in the plate width direction of the region A is within ± 20%.