Method for producing press-molded article

Abstract

This method for manufacturing a press-molded article is provided with: a reference press-molded article shape acquisition step for acquiring a reference press-molded article shape (5); a wave-shaped blank press-molded product shape acquisition step for acquiring a wave-shaped blank press-molded product shape (9); a first deviation amount acquisition step for obtaining a deviation amount between the reference press-molded article shape (5) and the wave-shaped blank press-molded article shape (9); a periodically shifted wave-shaped press-molded blank shape acquisition step for acquiring a periodically shifted wave-shaped press-molded blank shape (13); a second deviation amount acquisition step for obtaining a deviation amount between the reference press-molded article shape (5) and the periodically shifted wave-shaped blank press-molded article shape (13); a countermeasure-requiring part determination step for determining a countermeasure-requiring part; a convex pattern imparting step of imparting convex patterns (23, 27) to the actual mold; and an actual press-forming step in which press-forming is performed using the actual mold to which the convex pattern (23, 27) has been imparted.

Description

Technical Field

[0001] The present invention relates to a method for producing a press-formed product, which reduces the influence of shape variation of a blank collected from a metal plate having shape variation in a press-formed product obtained by press-forming the blank. Background Art

[0002] In the process of improving the collision safety of automobile bodies due to the stricter collision safety standards for automobiles, the recent carbon dioxide emission regulations have also required the lightweighting of automobile bodies in order to improve the fuel efficiency of automobiles. In order to achieve both the above-mentioned collision safety performance and the lightweighting of the body, the body adopts a metal plate with higher strength than before.

[0003] In the past, the actual metal plate collected to obtain the blank of the stamping formed product was not a completely flat metal plate, but had a wave shape (shape variation). Therefore, the actual blank collected from the metal plate was not necessarily flat, and there was a situation with shape variation.

[0004] When a metal plate having such shape fluctuations is used as a blank and press-formed into a vehicle body part, the press-formed product obtained after the press-forming may deviate from the target dimensional accuracy due to the influence of the shape fluctuations.

[0005] For stamping molded products after stamping, as a technology for screening stamping molded products that deviate from the target dimensional accuracy, for example, Patent Documents 1 and 2 are disclosed. In addition, as a technology for taking a means of giving concavoconvexity to the surface of the stamping mold, there are Patent Documents 3 and 4.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 62-047504

[0007] Patent Document 2: Japanese Patent Application Publication No. 2019-002834

[0008] Patent Document 3: Japanese Patent Application Publication No. 2020-127959

[0009] Patent Document 4: Japanese Patent Application Laid-Open No. 3-077728

[0010] The technology disclosed in Patent Documents 1 and 2 is a technology for comparing the shapes of stamped products after stamping and identifying the parts with poor dimensional accuracy. In the technology disclosed in Patent Documents 1 and 2, due to the shape change of the blank before stamping, it is difficult to identify which part of the stamped product is susceptible to the shape change of the blank, and it is difficult to take countermeasures.

[0011] In addition, the blanks used for stamping are collected from metal plates such as steel plates by punching and shearing. Therefore, if multiple blanks are collected from metal plates with shape changes, the blanks collected from the same metal plate will have different concave and convex parts in each blank due to different collection positions. Therefore, in order to reduce the impact of the shape change of the blank, it is necessary to take countermeasures considering the differences in the shape change of each blank.

[0012] The technology disclosed in Patent Document 3 provides the surface of the die with concavoconvex shapes to retain oil between the die and the blank during stamping, thereby suppressing the friction between the die and the blank and facilitating the forming. In addition, the technology disclosed in Patent Document 4 provides the surface of the die with concavoconvex shapes to manufacture a metal plate with high design properties. Therefore, the technologies disclosed in Patent Documents 3 and 4 are not technologies for reducing the influence of the shape change of the blank, which is the purpose of the present invention. Summary of the invention

[0013] The present invention has been made in view of the above-mentioned problems, and its object is to provide a method for manufacturing a stamped product, which reduces the influence of the shape variation of the blank in the stamped product obtained by stamping a blank collected from a metal plate with shape variation.

[0014] In order to solve the above problems and achieve the purpose,

[0015] (1) The method for manufacturing a stamped product of the present invention reduces the influence of the shape variation of the blank collected from a metal plate with shape variation on the stamped product obtained by stamping, and is characterized in that it comprises: a reference stamped product shape acquisition step, in which a stamping analysis is performed when a flat blank model with a flat shape is performed using a stamping forming method using a prescribed mold model, and the shape of the stamped product after demolding is acquired as the reference stamped product shape; and a wavy blank stamped product shape acquisition step, in which a wavy blank with a prescribed wavy shape corresponding to the above-mentioned shape variation is generated. A wave-shaped blank model of a wave shape with a length and a specified amplitude, using the generated wave-shaped blank model to perform stamping analysis when stamping is performed using the above-mentioned specified mold model, and obtaining the shape of the stamped product after demolding as the wave-shaped blank stamped product shape; a first deviation amount acquisition step, in which the above-mentioned reference stamped product shape is compared with the above-mentioned wave-shaped blank stamped product shape, and the location and deviation amount of the deviation between the two shapes are calculated; a periodically offset wave-shaped blank stamped product shape acquisition step, in which one or more periodically offset wave-shaped blank models are generated, and the above-mentioned periodic deviation The shifted wave shape blank model has a wave shape whose amplitude and wavelength are the same as the wave shape in the above-mentioned wave shape blank model and is periodically offset. The generated periodically offset wave shape blank model is used to perform stamping analysis when stamping is performed using the above-mentioned specified mold model, and the shape of the stamped product after demolding is obtained as the shape of the stamped product of the periodically offset wave shape blank; a second deviation amount acquisition step, in which the above-mentioned reference stamped product shape is compared with one or more of the above-mentioned periodically offset wave shape blank stamped product shapes to determine the location and deviation amount of the two shape deviations; a step of determining the location requiring countermeasures, In this step, a portion of the stamped product corresponding to a portion where a deviation exceeding a threshold value is generated in the first deviation acquisition step and a portion where a deviation exceeding a threshold value is generated in the second deviation acquisition step is determined as a portion requiring countermeasures; a convex pattern imparting step, in which a convex pattern is imparted to the portion requiring countermeasures, or a portion where the portion requiring countermeasures and its surroundings are formed, in an upper die and a lower die of an actual die for forming the stamped product; and an actual stamping step, in which the blank is stamped using an upper die and a lower die to which the convex pattern is imparted.

[0016] (2) The manufacturing method of the stamped product of the present invention is based on the invention described in (1) above, and is characterized in that, in the above-mentioned first deviation amount acquisition step, the difference between the springback amount of the specified portion in the above-mentioned reference stamped product shape and the springback amount of the portion in the above-mentioned wave-shaped blank stamped product shape that is the same as the above-mentioned specified portion of the above-mentioned reference stamped product shape is obtained as the above-mentioned deviation amount, and in the above-mentioned second deviation amount acquisition step, the difference between the springback amount of the specified portion in the above-mentioned reference stamped product shape and the springback amount of the portion in the above-mentioned periodically offset wave-shaped blank stamped product shape that is the same as the above-mentioned specified portion of the above-mentioned reference stamped product shape is obtained as the above-mentioned deviation amount.

[0017] (3) The manufacturing method of the stamped product of the present invention is based on the invention described in (1) or (2) above, and is characterized in that the above-mentioned convex pattern is composed of a plurality of convex portions formed on a plane or a curved surface at a specified interval, the longitudinal and lateral lengths A of the above-mentioned convex portions are not less than 3 mm and not more than 50 mm, and the distance between adjacent convex portions is set to not less than 1.2A and not more than 2.0A. In the above-mentioned convex pattern imparting step, the above-mentioned convex pattern is imparted to the above-mentioned upper die and the above-mentioned lower die in a configuration in which the convex portion of the upper die is opposite to the plane or curved surface of the lower die, and the convex portion of the lower die is opposite to the plane or curved surface of the upper die. In the above-mentioned actual stamping step, the stamping is performed in a manner in which the distance between the lower surface of the above-mentioned convex portion of the above-mentioned upper die and the upper surface of the above-mentioned convex portion of the above-mentioned lower die at the lower dead point of the forming when the above-mentioned blank with a plate thickness of t (mm) is formed is not less than 0.1t and not more than 0.5t.

[0018] The manufacturing method of the stamped product of the present invention can determine the location of the stamped product where the shape change of the blank has a greater impact on the basis of also taking into account the differences in the shape changes in each blank, and reduce the impact of the shape change of the blank by taking countermeasures at the location. Therefore, in the manufacturing method of the stamped product of the present invention, stamped products with good dimensional accuracy can be manufactured, and even if blanks collected from metal plates with shape changes are used, stamped products with good dimensional accuracy can be produced with a high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is an explanatory diagram of each step of the method for manufacturing a press-formed product according to the embodiment.

[0020] Figure 2 This is an external view of a component that is a subject of the embodiment.

[0021] Figure 3 This is an illustration of a flat blank model.

[0022] Figure 4 It shows the use of Figure 3 A diagram showing the reference stamped product shape obtained by performing stamping analysis on a flat blank model and the amount of change in each part of the shape from the bottom dead center of the stamping.

[0023] Figure 5 This is an explanatory diagram of a corrugated blank model.

[0024] Figure 6 It shows the use of Figure 5 A graph showing the shape of a stamped product made of a corrugated blank obtained by performing stamping analysis on a corrugated blank model and the amount of change of each part of the shape from the bottom dead point of the stamping.

[0025] Figure 7 It shows that Figure 4 The standard stamping product shape and Figure 6 A diagram of the first deviation amount when the wave-shaped blank stamping product shape is compared.

[0026] Figure 8 is a wave with amplitude and wavelength Figure 5 An explanatory diagram of a period-shifted wave shape blank model in which the wave shape in the wave shape blank model is the same but the period is shifted by 1 / 4 wavelength.

[0027] Fig. 9 It shows the use of Figure 8 A graph showing the shape of a stamped product made of a periodically shifted corrugated blank obtained by performing stamping analysis on a periodically shifted corrugated blank model, and the amount of change in each portion of the shape from the bottom dead center of the stamping.

[0028] Fig.10 It shows that Figure 4 The standard stamping product shape and Fig. 9 A diagram of the second deviation amount when the periodic deviation of the wave-shaped blank and the stamped product shape are compared.

[0029] Fig.11 Yes Figure 7 and Fig.10 The ranges of the first deviation amount and the second deviation amount shown are shown in the figure corresponding to the target shape.

[0030] Fig.12 This is an explanatory diagram of a convex pattern given to a mold.

[0031] Fig.13 This is a diagram showing a reference stamped product shape obtained by performing a stamping analysis using a die model provided with a convex pattern, and the amount of change of each portion of the shape from the bottom dead center of the stamping.

[0032] Fig.14The diagram shows the shape of a stamped product of a wave-shaped blank obtained by performing stamping analysis using a die model with a convex pattern, and the amount of change of each portion of the shape from the bottom dead point of the stamping.

[0033] Fig.15 It shows that Fig.13 The standard stamping product shape and Fig.14 A diagram of the first deviation amount when the wave-shaped blank stamping product shape is compared.

[0034] Fig.16 The figure shows the shape of a periodically offset wave-shaped blank stamped product obtained by performing stamping analysis using a die model with a convex pattern, and the amount of change of each part of the shape from the bottom dead center of the stamping.

[0035] Fig.17 It shows that Fig.13 The standard stamping product shape and Fig.16 A diagram of the second deviation amount when the periodic deviation of the wave-shaped blank and the stamped product shape are compared.

[0036] Fig.18 Yes Fig.15 and Fig.17 The ranges of the first deviation amount and the second deviation amount shown are shown in the figure corresponding to the target shape.

[0037] Fig.19 is a wave with amplitude and wavelength Figure 5 An explanatory diagram of a period-shifted wave shape blank model in which the wave shape in the wave shape blank model is the same but the period is shifted by 1 / 2 wavelength.

[0038] Fig. 20 It shows the use of Fig.19 A graph showing the shape of a stamped product made of a periodically shifted corrugated blank obtained by performing stamping analysis on a periodically shifted corrugated blank model, and the amount of change in each portion of the shape from the bottom dead center of the stamping.

[0039] Fig.21 It shows that Figure 4 The standard stamping product shape and Fig. 20 A diagram of the second deviation amount when the periodic deviation of the wave-shaped blank and the stamped product shape are compared.

[0040] Fig. 22 Yes Figure 7 and Fig.21 The ranges of the first deviation amount and the second deviation amount shown are shown in the figure corresponding to the target shape.

[0041] Fig.23The figure shows the shape of a periodically offset wave-shaped blank stamped product obtained by performing stamping analysis using a die model with a convex pattern, and the amount of change of each part of the shape from the bottom dead center of the stamping.

[0042] Fig.24 It shows that Fig.13 The standard stamping product shape and Fig.23 A diagram of the second deviation amount when the periodic deviation of the wave-shaped blank and the stamped product shape are compared.

[0043] Fig.25 Yes Fig.15 and Fig.24 The ranges of the first deviation amount and the second deviation amount shown are shown in the figure corresponding to the target shape. DETAILED DESCRIPTION

[0044] Hereinafter, an embodiment of the method for producing a press-formed product of the present invention will be described. However, the present invention is not limited to this embodiment.

[0045] The method for manufacturing a stamped product of the embodiment is a method for reducing the influence of the shape variation of the blank in the stamped product when the blank is collected from a metal plate with shape variation (convex and concave) and subjected to stamping such as collision forming and stretch forming. Specifically, Figure 1 As shown, the manufacturing method of the stamped product of the embodiment comprises a reference stamped product shape acquisition step S1 to an actual stamping step S15. Figure 2 The punched product 1 shown is punched into a target shape as an example, and each structure is described in detail below. In addition, in this embodiment, a blank composed of a 1.5 GPa grade steel plate with a plate thickness of 1.2 mm and a corresponding blank model are used, but it is not limited to this.

[0046] <Steps for obtaining the standard stamping product shape>

[0047] The reference stamping product shape acquisition step S1 is to use Figure 3 The flat blank model 3 shown in the figure is subjected to stamping analysis using a predetermined die model, and the shape of the stamped product after demolding is obtained as the reference stamped product shape. In addition, the "stamping analysis" of this description includes an analysis of obtaining the shape of the lower dead point of the forming, and an analysis of obtaining the shape after demolding, that is, after springback.

[0048] The flat blank model 3 is a blank model generally used in conventional press forming analysis, and has a flat shape without irregularities.

[0049] The stamping analysis is usually performed by CAE analysis such as finite element method (FEM). There are collision forming, stretch forming and the like in stamping, but in this embodiment, collision forming is described as an example.

[0050] Figure 4 : is a figure which shows the reference stamping molded product shape 5 after demolding obtained by performing stamping molding analysis. Figure 4 In the figure, the amount of change from the lower dead point of molding is shown by numerical values ​​and color shades. The amount of change refers to the value obtained by subtracting the height of the part corresponding to the shape of the lower dead point of molding from the height of each part of the shape of the stamped product after demolding and rebounding after stamping, which is equivalent to the amount of springback in the stamping direction. When the difference in height (amount of change) is + (positive), it is convex compared to the shape of the lower dead point of molding. When the difference in height (amount of change) is - (negative), it is concave compared to the shape of the lower dead point of molding. Figure 4 In the molding process, the color of the concave portion is made lighter than the bottom dead center shape, and the color of the convex portion is made darker. Figure 4 The + in the number shown is the change in the convex direction (near the paper), and the - is the change in the concave direction (inside the paper), and the unit is mm.

[0051] In this example, if Figure 4 As shown, the change in the left end portion (portion A) of the reference stamping molded product shape 5 is 1.06 mm. In addition, the left end (portion B) of the top plate portion of the reference stamping molded product shape 5 is 0.63 mm. In addition, the longitudinal center portion (portion C) of the reference stamping molded product shape 5 is 6.02 mm. In addition, the right end (portion D) of the lower flange portion of the reference stamping molded product shape 5 is 1.10 mm. In addition, the right end (portion E) of the reference stamping molded product shape 5 is -2.61 mm.

[0052] <Steps for obtaining the shape of a stamped product from a corrugated blank>

[0053] The wave-shaped blank stamped product shape acquisition step S3 is a step of performing stamping analysis similar to the reference stamped product shape acquisition step S1 using a blank model corresponding to the shape variation of the metal plate to acquire the shape of the stamped product after demolding.

[0054] In the corrugated blank press-formed product shape acquisition step S3, first, a corrugated blank model 7 having a shape corresponding to the shape variation of the metal plate is generated. Figure 5 (a) is a diagram showing an example of a corrugated blank model 7, and the specific shape will be described below.

[0055] Figure 5The corrugated blank model 7 shown in (a) is a corrugated blank model having a predetermined wavelength and a predetermined amplitude. Figure 5 The shades in (a) represent the concavity and convexity. The darker part is convex toward the front of the paper, and the lighter part is concave toward the back of the paper. Observe from the direction of the hollow arrow Figure 5 The state obtained by (a) is Figure 5 (b), the local enlarged view is Figure 5 (c). Figure 5 The example shown is a plate with a thickness of 1.2 mm, a wave amplitude of 5.0 mm (±2.5 mm), and a wavelength (see Figure 5 (d)) 320mm shape. In addition, the starting position and the ending position of the wave shape set in the blank do not need to be the end of the metal plate. In addition, Figure 5 (e) is emphasized Figure 5 (a) is a diagram showing the wave-shaped concavity and convexity.

[0056] In addition, the corrugated blank model 7 may also be generated based on the measurement result by measuring the shape of the actual blank collected from a predetermined position of a metal plate having a shape variation. For example, the corrugated blank model 7 may also be generated by measuring the shape of the actual blank by a three-dimensional shape measuring device based on a laser rangefinder, etc., and using a representative wavelength and amplitude in the measurement result.

[0057] Next, in the corrugated blank stamping product shape acquisition step S3, a stamping analysis is performed during stamping using the same predetermined die model as in the reference stamping product shape acquisition step S1 using the corrugated blank model 7. Then, the stamping product shape after demolding is acquired as the corrugated blank stamping product shape 9. Figure 6 FIG. 1 is a diagram showing a shape 9 of a stamped product of a corrugated blank obtained by performing stamping analysis. Figure 6 The colors, values, and Figure 4 In this case, Figure 6 As shown, the change in the left end portion (portion A) of the wavy blank stamped product shape 9 is 1.37 mm. In addition, the left end (portion B) of the top plate portion of the wavy blank stamped product shape 9 is 0.72 mm. In addition, the central portion (portion C) in the longitudinal direction of the wavy blank stamped product shape 9 is 6.02 mm. In addition, the right end (portion D) of the lower flange portion of the wavy blank stamped product shape 9 is 0.96 mm. In addition, the right end (portion E) of the wavy blank stamped product shape 9 is -2.11 mm.

[0058] <First deviation amount acquisition step>

[0059] The first deviation amount acquisition step S5 is to obtain the reference stamped product shape 5 ( Figure 4 ) and wave-shaped blank stamping product shape 9 ( Figure 6 ) to compare the two shapes and find out the location and deviation amount (first deviation amount) of the two shape deviations.

[0060] In this embodiment, the shape of the stamped product at the lower dead point of the forming is taken as the reference shape, the change amount (springback amount) of each part of the stamped product shape after demolding relative to the reference shape is obtained, and the difference between the change amounts of the two stamped product shapes is obtained as the deviation amount. That is, the first deviation amount obtained in the first deviation amount acquisition step S5 refers to the change amount ( Figure 6 ) minus the change in the reference stamped product shape 5 using a flat blank model ( Figure 4 ). Therefore, when the first deviation is + (positive), the portion of the wavy blank stamping product shape 9 is convex compared to the reference stamping product shape 5. In addition, when the first deviation is - (negative), the portion of the wavy blank stamping product shape 9 is concave compared to the reference stamping product shape 5.

[0061] Figure 7 is a graph showing the first deviation amount obtained as described above. Figure 7 As shown, the first deviation of the wavy blank stamping product shape 9 and the reference stamping product shape 5 is 0.31 mm at the left end (part A). In addition, the above-mentioned first deviation is 0.09 mm at the left end (part B) of the top plate. In addition, the above-mentioned first deviation is 0.00 mm in the central part in the longitudinal direction (part C). In addition, the above-mentioned first deviation is -0.14 mm at the right end (part D) of the lower flange. In addition, the above-mentioned first deviation is 0.50 mm at the right end (part E).

[0062] <Steps for obtaining the shape of stamped products from periodically offset wave-shaped blanks>

[0063] The periodically offset corrugated blank stamped product shape acquisition step S7 is a step of using a corrugated blank model having a shape different from the corrugated blank model 7 to perform the same stamping analysis as the reference stamped product shape acquisition step S1 to acquire the shape of the stamped product after demolding.

[0064] In the period-shifted corrugated blank stamped product shape acquisition step S7 , first, a period-shifted corrugated blank model 11 having a corrugated shape having the same wavelength and amplitude as the corrugated blank model 7 but with a period shifted therefrom is generated. Figure 8 FIG. 1 is a diagram showing an example of a periodically shifted wave-shaped blank model 11 , and a specific shape will be described below.

[0065] Figure 8 The example shown in (a) is a blank model having a periodic wave shape, wherein the periodic wave shape has a predetermined wavelength and a predetermined amplitude. Figure 8 The light and dark in (a) show the wave shape. Observe from the direction of the hollow arrow Figure 8 The state obtained by (a) is Figure 8 (b), the local enlarged view is Figure 8 (c). Figure 8 In the example shown, the plate thickness is 1.2 mm, and the amplitude and wavelength of the wave shape are Figure 5 The wave-shaped blank model 7 is the same as the wave-shaped blank model 7, but the wave-shaped period is shifted to the right of the paper by 1 / 4 wavelength (refer to Figure 8 (d) and Figure 8 (e)).

[0066] Next, in the periodic offset wave-shaped blank stamping product shape acquisition step S7, the periodic offset wave-shaped blank model 11 is used to perform stamping analysis during stamping using the same prescribed mold model as the reference stamping product shape acquisition step S1. Then, the stamping product shape after demolding is obtained as the periodic offset wave-shaped blank stamping product shape 13. Fig. 9 1 is a diagram showing the shape 13 of a blank stamped product having a periodically offset wave shape. Fig. 9 The colors, values, and Figure 4 and Figure 6 In this case, Fig. 9 As shown, the change in the left end portion (portion A) of the periodically offset wavy blank stamping product shape 13 is 1.64 mm. In addition, the change in the left end (portion B) of the top plate portion of the periodically offset wavy blank stamping product shape 13 is 0.83 mm. In addition, the change in the lengthwise central portion (portion C) of the periodically offset wavy blank stamping product shape 13 is 6.13 mm. In addition, the change in the right end (portion D) of the lower flange portion of the periodically offset wavy blank stamping product shape 13 is 1.41 mm. In addition, the change in the right end (portion E) of the periodically offset wavy blank stamping product shape 13 is -2.96 mm.

[0067] <Second deviation amount acquisition step>

[0068] The second deviation amount acquisition step S9 is a step of comparing the reference stamped product shape 5 with the periodic offset wave-shaped blank stamped product shape 13 to obtain the position and deviation amount (second deviation amount) of the deviation between the two shapes. The method for obtaining the second deviation amount is the same as the method described in the first deviation amount acquisition step S5, so the description is omitted.

[0069] Fig.10It is a representation of the standard stamping molded product shape 5 ( Figure 4 ) and the periodic offset wave-shaped blank stamping product shape 13 ( Fig. 9 ) is compared with the second deviation. Fig.10 As shown, the second deviation of the periodically offset wavy blank stamping product shape 13 and the reference stamping product shape 5 is 0.58 mm at the left end (part A). In addition, the second deviation is 0.20 mm at the left end of the top plate (part B). In addition, the second deviation is 0.11 mm in the central part in the length direction (part C). In addition, the second deviation is 0.31 mm at the right end of the lower flange (part D). In addition, the second deviation is -0.35 mm at the right end (part E).

[0070] <Steps for determining areas requiring countermeasures>

[0071] The countermeasure-required portion determining step S11 is a step of determining, as a countermeasure-required portion, a portion of the stamped product 1 corresponding to the portion having the first deviation exceeding the threshold value in the first deviation obtaining step S5 and the portion having the second deviation exceeding the threshold value in the second deviation obtaining step S9.

[0072] For example, in the case of assembling a vehicle body component by overlapping and joining a plurality of stamped parts, if the shape of the stamped parts (especially the flange part, etc.) has a large deviation, it becomes difficult to join the stamped parts together, and sometimes countermeasures are required. Therefore, in this embodiment, the part that is assumed to have a large influence (large deviation) caused by the shape change of the blank is determined as the part requiring countermeasures, and countermeasures are taken to reduce the influence.

[0073] Fig.11 The first deviation amount (see Figure 7 ) and the second deviation amount obtained in the second deviation amount acquisition step S9 (refer to Fig.10 ) Both sides correspond to the target shape of the stamped product 1. Fig.11 As shown, the deviation is 0.31mm to 0.58mm at part A. In addition, the deviation is 0.09mm to 0.20mm at part B. In addition, the deviation is 0.00mm to 0.11mm at part C. In addition, the deviation is -0.14mm to 0.31mm at part D. In addition, the deviation is -0.35mm to 0.50mm at part E.

[0074] For example, if the threshold in the measure-required site determination step S11 is set to ±0.15 mm, the sites where the deviation exceeds the threshold are site A, site B, site D, and site E. Therefore, in the measure-required site determination step S11, these sites are determined as the measure-required sites.

[0075] In this embodiment, as a countermeasure for reducing the influence of the shape change of the blank, a convex pattern is given to the part of the actual mold for forming the stamping molded product, and the stamping is performed using the actual mold. The convex pattern is respectively given to the part of the upper mold and the lower mold constituting the actual mold. Fig.12 1 is a diagram showing an example of a convex pattern given to an actual mold. The shape of the convex pattern will be described.

[0076] Fig.12 (a) is a side view of the convex pattern 23 of the upper mold 21 and the convex pattern 27 of the lower mold 25 at the molding bottom dead point. Fig.12 (b) is Fig.12 (a) CC view. Fig.12 In (b), the position of the convex pattern 27 of the opposing lower mold 25 is shown by a dotted line. Fig.12 (a) and Fig.12 As shown in (b) of FIG. 1 , the convex patterns 23 and 27 of the present embodiment are composed of a plurality of convex portions 23a and 27a (convex portion groups) formed on a flat surface or a curved surface of the surface of the upper mold 21 or the lower mold 25 at predetermined intervals.

[0077] The front end of the convex portion 23a, 27a is in the shape of a square with a side length of A (mm). Such convex portions 23a, 27a are arranged in a manner of being arranged at a predetermined distance B (mm) in the vertical and horizontal directions to form regular convex patterns 23, 27. Fig.12 The convex patterns 23 and 27 and the convex parts 23 a and 27 a as described above can be press-formed while suppressing the shape variation of the portion requiring countermeasures, thereby reducing the influence of the shape variation of the blank.

[0078] In addition, the size (longitudinal and lateral length) A of the front end surface of the convex portion 23a, 27a is preferably set to be greater than 3mm and less than 50mm. If the size A of the front end surface of the convex portion 23a, 27a is set to less than 3mm, there is a situation where the shape change (wave shape) of the blank after stamping and forming remains in the stamping molded product and the effect becomes smaller. In addition, if the size A of the front end surface of the convex portion 23a, 27a is set to exceed 50mm, it becomes a size exposed from the top plate portion, flange portion and other parts of the mold, and the blank is pressed with the wider surface of the front end of the convex portion, resulting in a molding similar to the case without a convex portion and no effect.

[0079] In addition, the distance B between adjacent convex portions can be set to be greater than 1.2A and less than 2.0A relative to the size A of the front end surface of the convex portions 23a and 27a. If the distance B (mm) between adjacent convex portions is set to be less than 1.2A or greater than 2.0A, there is a situation where the shape change (wave shape) of the blank after stamping remains in the stamped product, which is not preferred.

[0080] also, Fig.12 The number, arrangement and shape of the front end of the convex portions 23a and 27a shown are examples and do not limit the form of the convex pattern of the present invention. For example, the shape of the front end of the convex portion may be rectangular or circular.

[0081] In addition, if Fig.12 (a) and Fig.12 As shown in (b), the convex pattern 23 given to the upper mold 21 and the convex pattern 27 given to the lower mold 25 can be set so that the convex parts are not opposite to each other. That is, when the convex patterns 23 and 27 are given, the convex patterns 23 and 27 can be given to the upper mold 21 and the lower mold 25 in a configuration in which the convex part 23a of the upper mold 21 is opposite to the plane 25a (or curved surface) of the lower mold 25, and the convex part 27a of the lower mold 25 is opposite to the plane 21a (or curved surface) of the upper mold 21.

[0082] In addition, when a blank having a plate thickness of t (mm) is formed, the distance d between the lower surface of the convex portion 23a of the upper die 21 and the upper surface of the convex portion 27a of the lower die 25 at the lower dead point of the forming is preferably set to be greater than 0.1t and less than 0.5t. Thus, when the blank having shape changes is clamped by the upper die 21 and the lower die 25, a new alternating micro strain can be given to the portion of the blank surface corresponding to the portion requiring countermeasures. As a result, the shape change of the portion requiring countermeasures is alleviated by the strain, and the influence of the shape change of the blank is easily suppressed.

[0083] In addition, if the distance d is set to less than 0.1t, the amount of strain is too large, resulting in the front end surface shape of the protrusions 23a and 27a being clearly transferred to the surface of the stamped product after stamping, so it is not preferred. In addition, if the distance d is set to more than 0.5t, the amount of strain is insufficient, and the effect of alleviating the shape change of the blank becomes small, so it is not preferred.

[0084] In the present embodiment, the effect of performing press molding using the upper mold 21 and the lower mold 25 provided with the convex patterns 23 and 27 was confirmed by press molding analysis, and thus will be described below.

[0085] In the stamping analysis described below, the front end surface shape of the convex portions 23a and 27a is set to a 3 mm square (A = 3 mm), and the distance B between adjacent convex portions is set to 4.5 mm. In addition, the convex pattern 23 of the upper mold 21 and the convex pattern 27 of the lower mold 25 are provided in a manner that the convex portions do not face each other. Specifically, Fig.12 As shown in (b), the positions of the convex portion 23a of the upper mold 21 and the convex portion 27a of the lower mold 25 are set to be offset from each other in the horizontal direction and the vertical direction of the paper. In addition, the positional relationship between the convex portion of the upper mold and the convex portion of the lower mold is not limited to this, and they can also be offset only in the horizontal direction or the vertical direction of the paper.

[0086] The distance d between the lower surface of the convex portion 23a of the upper die 21 and the upper surface of the convex portion 27a of the lower die 25 at the bottom dead point of the molding is 0.36 mm. As described above, since the thickness t of the blank in this embodiment is 1.2 mm, the relationship between the distance d and the blank thickness t is d=0.3t.

[0087] In addition, in the present embodiment, the convex patterns 23 and 27 are given to the parts corresponding to the parts requiring countermeasures in the prescribed mold model used for the above-mentioned stamping analysis. Then, in the present embodiment, the same analysis as the reference stamping product shape acquisition step S1 to the second deviation acquisition step S9 is performed using this mold model (hereinafter referred to as the "convex pattern assigned mold model"). In addition, the change amount and deviation amount in the following description are obtained by comparing with Figures 4 to 11 The method shown is the same as that used to calculate .

[0088] Fig.13 This is a diagram showing how to use a convex pattern to impart a mold model to a flat blank model 3 (refer to Figure 3 ) is a diagram of a reference stamping product shape 31 obtained by performing stamping analysis. Fig.13 In FIG. 1 , a grid is annotated on the region (strain application region 33) where strain is applied to the convex patterns 23 and 27 of the mold model by the convex patterns ( Figures 14 to 18 Same).

[0089] like Fig.13 As shown, when the stamping analysis was performed using a convex pattern to impart a mold model, the change in part A of the reference stamping molded product shape 31 was 1.29 mm. In addition, the change in part B of the reference stamping molded product shape 31 was 0.07 mm. The change in part C of the reference stamping molded product shape 31 was 6.50 mm. In addition, the change in part D of the reference stamping molded product shape 31 was 2.10 mm. In addition, the change in part E of the reference stamping molded product shape 31 was 1.80 mm.

[0090] Fig.14 This is a diagram showing the use of a convex pattern to impart a die model to a corrugated blank model 7 (refer to Figure 5 ) is a diagram of the shape 35 of the wave-shaped blank stamped product obtained by performing stamping analysis. Fig.14 As shown, the amount of change in the portion A of the corrugated blank stamping product shape 35 is 1.45 mm. In addition, the amount of change in the portion B of the corrugated blank stamping product shape 35 is 0.12 mm. In addition, the amount of change in the portion C of the corrugated blank stamping product shape 35 is 6.50 mm. In addition, the amount of change in the portion D of the corrugated blank stamping product shape 35 is 2.03 mm. In addition, the amount of change in the portion E of the corrugated blank stamping product shape 35 is 2.05 mm.

[0091] Fig.15 It is a representation of the standard stamping molded product shape 31 ( Fig.13 ) and wave-shaped blank stamping product shape 35 ( Fig.14 ) to obtain the first deviation amount by comparison. Fig.15 As shown, the first deviation amount of the reference stamping product shape 31 and the wave-shaped blank stamping product shape 35 when the stamping analysis is performed using a convex pattern to give a mold model is 0.16mm at part A. In addition, the above-mentioned first deviation amount is 0.05mm at part B. In addition, the above-mentioned first deviation amount is 0.00mm at part C. In addition, the above-mentioned first deviation amount is -0.07mm at part D. In addition, the above-mentioned first deviation amount is 0.25mm at part E.

[0092] Fig.16 This is a diagram showing the use of a convex pattern to impart a periodic offset wave-shaped blank model 11 (see Figure 8 ) is a diagram of the periodic offset wave-shaped blank stamping product shape 37 obtained by performing stamping analysis. Fig.16 As shown, the amount of change in the portion A of the periodically offset wavy blank stamping product shape 37 is 1.58 mm. In addition, the amount of change in the portion B of the periodically offset wavy blank stamping product shape 37 is 0.17 mm. In addition, the amount of change in the portion C of the periodically offset wavy blank stamping product shape 37 is 6.60 mm. In addition, the amount of change in the portion D of the periodically offset wavy blank stamping product shape 37 is 2.26 mm. In addition, the amount of change in the portion E of the periodically offset wavy blank stamping product shape 37 is 1.63 mm.

[0093] Fig.17 It is a representation of the standard stamping molded product shape 31 ( Fig.13 ) and the periodically offset wave-shaped blank stamping product shape 37 ( Fig.16 ) to obtain the second deviation amount by comparison. Fig.17As shown, the second deviation amount of the reference stamped product shape 31 and the periodically offset wave-shaped blank stamped product shape 37 is 0.29mm at portion A. In addition, the above-mentioned second deviation amount is 0.10mm at portion B. In addition, the above-mentioned second deviation amount is 0.10mm at portion C. In addition, the above-mentioned second deviation amount is 0.16mm at portion D. In addition, the above-mentioned second deviation amount is -0.17mm at portion E.

[0094] Fig.18 Yes Fig.15 The first deviation and Fig.17 The second deviation amount corresponds to the target shape shown in the figure. Fig.18 As shown, the first deviation and the second deviation are 0.16mm to 0.29mm at part A. In addition, the first deviation and the second deviation are 0.05mm to 0.10mm at part B. In addition, the first deviation and the second deviation are 0.00mm to 0.10mm at part C. In addition, the first deviation and the second deviation are -0.07mm to 0.16mm at part D. In addition, the first deviation and the second deviation are -0.17mm to 0.25mm at part E. Fig.18 The deviation of Fig.11 The amount of deviation is reduced compared to that before the countermeasures shown. Therefore, it was confirmed that the use of a convex pattern to provide a die model has the effect of reducing the influence of the shape variation of the blank.

[0095] <Procedure for providing convex pattern>

[0096] The convex pattern imparting step S13 is to impart the convex pattern to the actual mold. Fig.12 The convex patterns 23 and 27 described in the above are provided. The convex patterns 23 and 27 can be provided by laser processing, etching, etc. on the surface of the actual mold. The convex patterns 23 and 27 are provided to the parts requiring countermeasures in the upper mold 21 and the lower mold 25 of the actual mold, or to the parts requiring countermeasures and the parts around the parts. Fig.12 As described in the above, it is preferred that the convex portion 23a of the upper mold 21 faces the flat surface 25a or curved surface of the lower mold 25, and the convex portion 27a of the lower mold 25 faces the flat surface 21a or curved surface of the upper mold 21. Figure 13 to Figure 18 The same convex patterns 23 and 27 as those used in the stamping analysis described in the above are given to the die model.

[0097] <Actual stamping steps>

[0098] The actual stamping step S15 is a step of stamping the actual blank using the upper die 21 and the lower die 25 to which the convex patterns 23 and 27 are given in the convex pattern giving step S13. In the actual stamping step S15, as described above, it is preferred to perform stamping in such a manner that the distance d between the lower surface of the convex portion 23a of the upper die 21 and the upper surface of the convex portion 27a of the lower die 25 at the lower dead point of the forming is greater than or equal to 0.1t and less than or equal to 0.5t (t (mm) is the plate thickness of the blank).

[0099] If an actual blank with a shape variation is stamped using an actual die to which the convex patterns 23 and 27 are applied, the shape of the stamped product after stamping will be different from that of the actual blank. Fig.18 The analysis results are similar to those of the previous work. The influence of the shape variation of the blank is reduced, and good dimensional accuracy is obtained.

[0100] As described above, according to the present embodiment, it is possible to determine the location where the shape change of the blank has a greater impact, and take appropriate countermeasures, so that a stamped product with good dimensional accuracy can be stably obtained. In addition, in the present embodiment, the pattern generates a plurality of blank models assuming blanks with shape changes, and the deviation amount in each case is calculated to determine the location requiring countermeasures, so that the difference in shape changes generated between each actual blank is taken into account.

[0101] In addition, only one periodic offset wave shape blank model is generated above, but multiple periodic offset wave shape blank models can also be generated. In this case, the wave shape of the periodic offset wave shape blank model can be set to be periodically staggered (the wavelength and amplitude are common in the wave shape blank model and all periodic offset wave shape blank models). By adding a pattern of a blank model assuming a blank with shape variation, the difference in shape variation generated between each actual blank can be considered more specifically.

[0102] In addition, in the above description, when calculating the deviation of the shapes of two stamped products, the difference in the amount of change (springback amount) from the lower dead point of the forming in the stamping forming direction is taken as the deviation, but the present invention is not limited to this. For example, the present invention can also be in the stamping forming direction, the difference obtained by subtracting the height of each part of the stamped product shape after demolding (after springback) on the other side from the height of each part of the stamped product shape after demolding (after springback) on the other side as the deviation. However, in this case, it is necessary to set a common fixed point in the two stamped product shapes, and there is a situation where the deviation varies depending on the method of selecting the fixed point. At this point, as in the present embodiment, if the changes based on the shape at the lower dead point of the forming, which is constant regardless of the presence or absence of shape change of the blank, are compared with each other, it is preferred that the deviation can be accurately and easily calculated.

[0103] In addition, although this embodiment has been described by taking collision forming as an example, stretch forming may also be employed.

[0104] In addition, there is a case where a concave-convex pattern is formed on a stamped product after stamping by using an upper die and a lower die to which a convex pattern is given. In this case, after the actual stamping step S15, a coining process may be further provided, in which the stamped product with the concave-convex pattern is re-punched to flatten the concave-convex pattern. By flattening the concave-convex pattern in the coining process, strain is applied to the part with the concave-convex pattern and its surroundings to perform work hardening, thereby further improving the rigidity. As a result, the wave shape (shape change) remaining in the stamped product can be suppressed, and the dimensional accuracy can be improved.

[0105] Example

[0106] In order to confirm the effect of the present invention, Figure 1 In this embodiment, the same as in the embodiment is used to manufacture the stamped product. Figure 2 The stamped product 1 of the embodiment is set as the target shape. In addition, the forming of the CAE analysis in this embodiment is set as collision forming in the same manner as in the embodiment. In addition, the change amount and the deviation amount in this embodiment are obtained by the same method as in the embodiment.

[0107] First, in this embodiment, a flat blank model 3 (see Figure 3 ) The reference stamping product shape acquisition step S1 is implemented. The change amount of the reference stamping product shape 5 when the stamping analysis is performed on the flat blank model 3 using the prescribed die model is as follows. That is, the above-mentioned change amount is as follows Figure 4 As described in FIG. 1 , the diameter of the part A is 1.06 mm, the diameter of the part B is 0.63 mm, the diameter of the part C is 6.02 mm, the diameter of the part D is 1.10 mm, and the diameter of the part E is -2.61 mm.

[0108] In this embodiment, the corrugated blank mold 7 (see Figure 5 ) The step S3 of acquiring the shape of the corrugated blank stamping product is implemented. The change amount of the corrugated blank stamping product shape 9 when the stamping analysis is performed on the corrugated blank model 7 using the prescribed die model is as follows. That is, the above change amount is as follows Figure 6 As described in FIG. 1 , the diameter of the part A is 1.37 mm, the diameter of the part B is 0.72 mm, the diameter of the part C is 6.02 mm, the diameter of the part D is 0.96 mm, and the diameter of the part E is −2.11 mm.

[0109] In addition, in the present embodiment, in the first deviation amount acquisition step S5, the reference stamping molded product shape 5 ( Figure 4) and wave-shaped blank stamping product shape 9 ( Figure 6 ) to compare the two shapes and find the deviation (first deviation). The first deviation is as follows Figure 7 As described in FIG. 1 , the thickness at site A is 0.31 mm, the thickness at site B is 0.09 mm, the thickness at site C is 0.00 mm, the thickness at site D is −0.14 mm, and the thickness at site E is 0.50 mm.

[0110] Next, in this embodiment, in the periodically offset wave-shaped blank stamping product shape acquisition step S7, a wave-shaped blank model having a shape different from the wave-shaped blank model 7 is generated. Then, in this embodiment, the stamping analysis is performed using the same prescribed die model as described above, and the shape of the stamped product after demolding is acquired. As a wave-shaped blank model having a shape different from the wave-shaped blank model 7, in the embodiment, Figure 8 The periodic offset wave shape blank model 11 described in Fig.19 The periodically offset corrugated blank model 41 is shown. The specific shape of the periodically offset corrugated blank model 41 will be described below.

[0111] Fig.19 The example shown is a blank model having a periodic wave shape, the periodic wave shape having a prescribed wavelength and a prescribed amplitude, Fig.19 The shades in (a) show the unevenness. Observe from the direction of the hollow arrow Fig.19 The state obtained by (a) is Fig.19 (b), the local enlarged view is Fig.19 (c). Fig.19 In the example shown, the plate thickness is 1.2 mm, and the amplitude and wavelength of the concave and convex are Figure 5 The wave-shaped blank model 7 is the same as the wave-shaped blank model 7, but the wave-shaped period is shifted to the right of the paper by 1 / 2 wavelength (refer to Fig.19 (d) and Fig.19 (e)).

[0112] Fig. 20 It means using the specified mold model to Fig.19 The periodic offset wave shape blank model 41 is subjected to the stamping analysis, and the periodic offset wave shape blank stamping product shape 43 is shown in FIG. Fig. 20As shown, the amount of change in the portion A of the periodically offset wavy blank stamped product shape 43 when the stamping analysis is performed using the specified mold model is 0.85 mm. In addition, the amount of change in the portion B of the periodically offset wavy blank stamped product shape 43 is 0.88 mm. In addition, the amount of change in the portion C of the periodically offset wavy blank stamped product shape 43 is 5.95 mm. In addition, the amount of change in the portion D of the periodically offset wavy blank stamped product shape 43 is 0.86 mm. In addition, the amount of change in the portion E of the periodically offset wavy blank stamped product shape 43 is -2.64 mm.

[0113] In addition, in the present embodiment, in the second deviation amount acquisition step S9, the reference stamping molded product shape 5 ( Figure 4 ) and the periodically offset wave-shaped blank stamping product shape 43 ( Fig. 20 ) to compare and find the deviation (second deviation). Fig.21 As shown, the second deviation of the periodically offset wave-shaped blank stamping product shape 43 and the reference stamping product shape 5 is -0.21mm at part A, 0.25mm at part B, -0.07mm at part C, -0.24mm at part D, and -0.03mm at part E.

[0114] Fig. 22 The first deviation amount ( Figure 7 ) and the second deviation amount ( Fig.21 ) are shown in the figure corresponding to the stamped product 1 (target shape). Fig. 22 As shown, the deviation before the countermeasure is -0.21mm~0.31mm at part A, 0.09mm~0.25mm at part B, -0.07mm~0.00mm at part C, -0.24mm~-0.14mm at part D, and ~0.03mm~0.50mm at part E.

[0115] Here, for example, if the threshold in the measure-required site identification step S11 is set to ±0.15 mm, the sites where the deviation exceeds the threshold are site A, site B, site D, and site E. Thus, these sites are identified as the measure-required sites.

[0116] In this embodiment, as a countermeasure for reducing the influence of the shape change of the blank, the surface of the actual mold corresponding to the above-mentioned portion requiring countermeasures is also given Fig.12 The convex patterns 23 and 27 described in the above are shown in FIG. In this embodiment, the effect was confirmed by the press forming analysis, so the following will describe it.

[0117] In the stamping analysis described below, the front end surface shape of the convex portions 23a and 27a is set to a 3 mm square (A = 3 mm), and the distance B between adjacent convex portions is set to 4.5 mm. In addition, the convex pattern 23 of the upper mold 21 and the convex pattern 27 of the lower mold 25 are provided in a manner that the convex portions 23a and 27a are not opposite to each other. Specifically, Fig.12 As shown in (b), the positions of the convex portion 23a of the upper die 21 and the convex portion 27a of the lower die 25 are set to be offset from each other in the horizontal direction and the vertical direction of the paper. In addition, the distance d between the lower surface of the convex portion 23a of the upper die 21 and the upper surface of the convex portion 27a of the lower die 25 at the lower dead point of the molding is set to 0.36mm. The plate thickness t of the blank of this embodiment is 1.2mm as in the embodiment, so the relationship between the distance d and the plate thickness t of the blank is d=0.3t.

[0118] In this embodiment, the above-mentioned convex patterns 23 and 27 are assigned to the parts corresponding to the parts requiring countermeasures in the specified mold model, and the same analysis as the reference stamping product shape acquisition step S1 to the second deviation amount acquisition step S9 is implemented using the mold model (convex pattern assigned mold model).

[0119] The flat blank model 3 (refer to Figure 3 ) The change amount of the reference stamping product shape 31 when the stamping analysis is performed is as follows Fig.13 As described in , the change in the shape of the reference stamped product 31 at part A is 1.29 mm. In addition, the change in the shape of the reference stamped product 31 at part B is 0.07 mm. In addition, the change in the shape of the reference stamped product 31 at part C is 6.50 mm. In addition, the change in the shape of the reference stamped product 31 at part D is 2.10 mm. In addition, the change in the shape of the reference stamped product 31 at part E is 1.80 mm.

[0120] The convex pattern is used to give the mold model to the corrugated blank model 7 (refer to Figure 5 ) The change in the shape 35 of the wave-shaped blank stamped product when the stamping analysis is performed is as follows Fig.14 As described in , the amount of change in the shape 35 of the wavy blank stamped product is 1.45 mm at portion A. In addition, the amount of change in the shape 35 of the wavy blank stamped product is 0.12 mm at portion B. In addition, the amount of change in the shape 35 of the wavy blank stamped product is 6.50 mm at portion C. In addition, the amount of change in the shape 35 of the wavy blank stamped product is 2.03 mm at portion D. In addition, the amount of change in the shape 35 of the wavy blank stamped product is 2.05 mm at portion E.

[0121] The standard stamped product shape 31 ( Fig.13) and wave-shaped blank stamping product shape 35 ( Fig.14 ) and the first deviation is obtained by comparison. Fig.15 As described in , the first deviation amount is 0.16 mm at the portion A. In addition, the first deviation amount is 0.05 mm at the portion B. In addition, the first deviation amount is 0.00 mm at the portion C. In addition, the first deviation amount is -0.07 mm at the portion D. In addition, the first deviation amount is 0.25 mm at the portion E.

[0122] Fig.23 This is a diagram showing the use of a convex pattern to impart a periodically offset wave-shaped blank model 41 (see Fig.19 ) is a diagram of the periodic offset wave-shaped blank stamping product shape 51 obtained by performing stamping analysis. Fig.23 As shown, the amount of change in the portion A of the periodically offset wavy blank stamping product shape 51 when the convex pattern is given to the mold model is 1.19 mm. In addition, the amount of change in the portion B of the periodically offset wavy blank stamping product shape 51 is 0.20 mm. In addition, the amount of change in the portion C of the periodically offset wavy blank stamping product shape 51 is 6.44 mm. In addition, the amount of change in the portion D of the periodically offset wavy blank stamping product shape 51 is 1.98 mm. In addition, the amount of change in the portion E of the periodically offset wavy blank stamping product shape 51 is 1.82 mm.

[0123] Fig.24 It is a representation of the standard stamping molded product shape 31 ( Fig.13 ) and the periodically offset wave-shaped blank stamping product shape 51 ( Fig.23 ) to obtain the second deviation amount by comparison. Fig.24 As shown, the second deviation amount of the reference stamping product shape 31 and the periodic offset wave-shaped blank stamping product shape 51 when the convex pattern is used to impart the mold model is -0.10mm at part A. In addition, the above-mentioned second deviation amount is 0.13mm at part B. In addition, the above-mentioned second deviation amount is -0.06mm at part C. In addition, the above-mentioned second deviation amount is -0.12mm at part D. In addition, the above-mentioned second deviation amount is 0.02mm at part E.

[0124] Fig.25 Yes Fig.15 The first deviation and Fig.24 The second deviation amount of both sides corresponds to the stamped product 1 (target shape) and is shown in the figure. Fig.25As shown, the deviation amount in the case of using the convex pattern to impart the mold model is -0.10mm to 0.16mm at the portion A. In addition, the above deviation amount is 0.05mm to 0.13mm at the portion B. In addition, the above deviation amount is -0.06mm to 0.00mm at the portion C. In addition, the above deviation amount is -0.12mm to -0.07mm at the portion D. In addition, the above deviation amount is 0.02mm to 0.25mm at the portion E. Fig.25 The deviation of Fig. 22 Therefore, it was confirmed that the effect of reducing the influence of the shape variation of the blank was achieved by providing the mold with a convex pattern corresponding to the portion requiring the countermeasure.

[0125] Therefore, in the convex pattern imparting step S13, the convex patterns 23 and 27 that are the same as those of the convex pattern imparting mold model are imparted to the actual mold surface. Specifically, the convex patterns 23 and 27 are imparted to the portion requiring countermeasures in this embodiment, or to the portion of the mold that forms the portion requiring countermeasures and its surroundings. Then, in the actual stamping step S15, the actual blank with shape variation is stamped using the actual mold imparted with the convex patterns 23 and 27. In addition, the actual blank uses a 1.5 GPa grade steel plate with a plate thickness of 1.2 mm equivalent to the above-mentioned blank model.

[0126] In this embodiment, the shape of the stamped product obtained by stamping in the actual stamping step S15 is similar to Fig.25 The analysis results are similar to those of the previous work. The influence of the shape variation of the blank is reduced, and good dimensional accuracy is obtained.

[0127] Industrial Applicability

[0128] The present invention can provide a method for producing a press-formed product in which the influence of shape variation of a blank is reduced.

[0129] Description of Reference Numerals

[0130] 1… Stamped product (target shape); 3… Flat blank model; 5… Reference stamped product shape (used by the specified die model); 7… Wave-shaped blank model; 9… Wave-shaped blank stamped product shape (used by the specified die model); 11… Periodically offset wave-shaped blank model; 13… Periodically offset wave-shaped blank stamped product shape (used by the specified die model); 21… Upper die; 21a… Plane; 23… Convex pattern (upper die); 23a… Convex part; 25… Lower die; 25a… Plane; 27… Convex pattern (lower die); 27a …convex portion; 31…reference stamping product shape (convex pattern is assigned to the mold model for use); 33…strain application area; 35…wave-shaped blank stamping product shape (convex pattern is assigned to the mold model for use); 37…periodically offset wave-shaped blank stamping product shape (convex pattern is assigned to the mold model for use); 41…periodically offset wave-shaped blank model (implementation); 43…periodically offset wave-shaped blank stamping product shape (used by the specified mold model); 51…periodically offset wave-shaped blank stamping product shape (convex pattern is assigned to the mold model for use).

Claims

1. A method for producing a stamped product, the method comprising reducing the influence of the shape variation of a blank collected from a metal plate having shape variation in a stamped product obtained by stamping the blank, The method for manufacturing the press-formed product is characterized by comprising: A reference stamping product shape acquisition step, in which a stamping analysis is performed when stamping is performed using a predetermined die model using a flat blank model, and the stamping product shape after demolding is acquired as the reference stamping product shape; A step of acquiring the shape of a corrugated blank stamped product, in which a corrugated blank model having a corrugated shape with a specified wavelength and a specified amplitude corresponding to the shape variation is generated, and a stamping analysis is performed when stamping is performed using the specified mold model using the generated corrugated blank model, and the shape of the stamped product after demolding is acquired as the shape of the corrugated blank stamped product; A first deviation amount acquisition step, in which the reference stamped product shape is compared with the wave-shaped blank stamped product shape to obtain a position and a deviation amount of the two shapes; A step of acquiring the shape of a stamped product of a periodically offset wave-shaped blank, in which one or more periodically offset wave-shaped blank models are generated, wherein the periodically offset wave-shaped blank model has a wave shape whose amplitude and wavelength are the same as the wave shape in the wave-shaped blank model and is periodically offset, and using the generated periodically offset wave-shaped blank model, a stamping analysis is performed when stamping is performed using the specified mold model, and the shape of the stamped product after demolding is acquired as the shape of the stamped product of the periodically offset wave-shaped blank; A second deviation amount acquisition step, in which the reference stamped product shape is compared with one or more of the periodically offset wave-shaped blank stamped product shapes to obtain the position and deviation amount of the two shapes; A step of determining a portion requiring countermeasures, in which a portion of the stamped product corresponding to a portion where a deviation exceeding a threshold value in the first deviation amount acquisition step is generated and a portion where a deviation exceeding a threshold value in the second deviation amount acquisition step is generated is determined as a portion requiring countermeasures; A convex pattern imparting step, in which a convex pattern is imparted to the portion requiring countermeasures, or to the portion where the portion requiring countermeasures and its surroundings are formed, in the upper die and the lower die of the actual die for forming the stamped product; as well as The actual press forming step is to press form the blank using the upper die and the lower die to which the convex pattern is applied.

2. The method for manufacturing a stamped product according to claim 1, wherein: In the first deviation amount acquisition step, the difference between the springback amount of a specified portion in the reference stamping product shape and the springback amount of the same portion as the specified portion of the reference stamping product shape in the wave-shaped blank stamping product shape is acquired as the deviation amount. In the second deviation amount acquisition step, the difference between the springback amount of a specified portion in the reference stamped product shape and the springback amount of the same portion as the specified portion of the reference stamped product shape in the periodic offset wave-shaped blank stamped product shape is acquired as the deviation amount.

3. The method for manufacturing a press-formed product according to claim 1 or 2, characterized in that: The convex pattern is composed of a plurality of convex portions formed at predetermined intervals on a flat surface or a curved surface, the longitudinal and lateral lengths A of the convex portions are greater than 3 mm and less than 50 mm, and the distance between adjacent convex portions is set to be greater than 1.2A and less than 2.0A, In the convex pattern imparting step, the convex pattern is imparted to the upper mold and the lower mold in a configuration in which the convex portion of the upper mold faces the flat surface or curved surface of the lower mold, and the convex portion of the lower mold faces the flat surface or curved surface of the upper mold, In the actual stamping step, stamping is performed in such a manner that the distance between the lower surface of the convex portion of the upper die and the upper surface of the convex portion of the lower die at the bottom dead point of the forming when the blank having a plate thickness t is formed is not less than 0.1t and not more than 0.5t, The unit of the plate thickness t is mm.

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