Method for producing press-molded article

Abstract

The invention provides a method for manufacturing a press-molded article, which can reduce the influence caused by the shape change of a blank. This method for manufacturing a press-molded article comprises: a reference press-molded article shape acquisition step for acquiring a reference press-molded article shape (5); a waveform-shaped blank press-formed product shape acquisition step for acquiring a waveform-shaped blank press-formed product shape (9); a first deviation amount acquisition step for obtaining a first deviation amount between the reference press-formed product shape (5) and the waveform-shaped blank press-formed product shape (9); a step for acquiring the shape of a periodically shifted waveform-shaped blank press-formed article, in which the shape (13) of the periodically shifted waveform-shaped blank press-formed article is acquired; a second deviation amount acquisition step for obtaining a second deviation amount between the reference press-formed article shape (5) and the periodically shifted waveform-shaped blank press-formed article shape (13); a countermeasure-needing part determination step: determining a countermeasure-needing part; and a rib application step of applying ribs to the actual mold.

Description

Technical Field

[0001] The present invention relates to a technology for producing a press-formed product by press-forming a blank collected from a metal plate having shape variations. The present invention relates to a method for producing a press-formed product capable of reducing the influence of the shape variations of the blank. Background Art

[0002] As the collision safety standards for automobiles become stricter, the demand for improved collision safety performance of automobile bodies has increased. Along with this demand, the recent carbon dioxide emission restrictions have led to the need to reduce the weight of automobile bodies in order to improve fuel efficiency. In order to achieve both collision safety performance and vehicle body weight reduction, there is a trend to use higher strength metal plates for vehicle bodies than before.

[0003] A press-formed product is manufactured by press-forming a blank. The actual metal plate from which the blank used for press-forming is obtained is not a metal plate with a completely flat surface, but has a corrugated shape (shape fluctuation) along the surface.

[0004] Therefore, the actual blank collected from the metal plate is not necessarily flat and may have shape variations.

[0005] When a blank having such shape fluctuations is press-formed into a vehicle body part, the press-formed product obtained after press-forming is affected by the shape fluctuations and may deviate from the target dimensional accuracy.

[0006] Regarding press-formed products after press forming, for example, Patent Documents 1 and 2 disclose techniques for screening out press-formed products that deviate from target dimensional accuracy.

[0007] In addition, Patent Document 3 describes a technology for suppressing springback generated in a stamped product. Patent Document 3 discloses a technology for providing ribs to a flange portion in order to balance the residual stress of a stamped product. Furthermore, Patent Document 4 discloses a technology for controlling the flow of material during stamping by providing ribs to a die during deep drawing, thereby suppressing springback.

[0008] Patent Document 5 discloses the use of a developed blank when performing press forming of a crash box. Patent Document 6 discloses a technique for providing ribs to portions of a press-formed product where cracks or wrinkles may occur.

[0009] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 62-047504 Patent Document 2: Japanese Patent Application Publication No. 2019-002834 Patent Document 3: Japanese Patent Application Publication No. 2009-255117 Patent Document 4: Japanese Patent Application Publication No. 2012-166225 Patent Document 5: Japanese Patent Re-Publication No. 2015-053075 Patent Document 6: Japanese Patent Re-Publication No. 2015-115348 Summary of the invention

[0010] Problems to be solved by the invention

[0011] The techniques disclosed in Patent Documents 1 and 2 compare the shapes of stamped products after stamping to identify the parts with poor dimensional accuracy after stamping. Therefore, the techniques disclosed in Patent Documents 1 and 2 are not techniques for identifying the parts of the shape change of the blank before stamping that affect the dimensional accuracy of the stamped product after stamping and taking countermeasures for the parts. In other words, the techniques disclosed in Patent Documents 1 and 2 do not reduce the impact caused by the shape change of the blank before stamping.

[0012] Furthermore, conventionally, it has not been possible to identify which part of a press-formed product is susceptible to the influence of the shape change of the blank, and it has been difficult to take countermeasures.

[0013] Furthermore, the blanks used in stamping are collected from metal plates such as steel plates by punching and shearing. Therefore, if multiple blanks are collected from a metal plate with a variable shape, the blanks collected from the same metal plate will have different concave and convex parts due to different collection positions.

[0014] Therefore, in order to reduce the influence of the shape variation of the blank, it is necessary to take measures taking into account the fact that the shape variation of each blank is different.

[0015] In addition, patent documents 3 and 4 disclose technologies for suppressing springback by providing ribs. However, the ribs are components that equalize or reduce the stress remaining in the stamped product released from the die after stamping due to the strain applied during the stamping process. Therefore, the technologies disclosed in patent documents 3 and 4 are aimed at controlling the material flow during the stamping process, and are not aimed at reducing the impact of the shape change of the blank as the object of the present invention.

[0016] In addition, when performing stamping of a stamped product, in the past, for example, as disclosed in Patent Document 5, an expanded blank is collected. Specifically, the expanded blank shape obtained by expanding the stamped product into a blank is obtained, and the expanded blank according to the expanded blank shape is collected from the metal plate. In addition, the so-called expanded blank means a blank having a shape obtained by expanding the stamped product into a plane.

[0017] Furthermore, Patent Document 6 discloses a technique for manufacturing a stamped product by providing ribs to a blank in order to suppress cracks and wrinkles during stamping. However, the ribs are not the ribs for reducing the influence of the shape change of the blank before stamping on the dimensional accuracy of the stamped product after stamping, which is the purpose of the present invention.

[0018] The present invention has been made to solve such a problem and has an object to reduce the influence of the shape variation of the blank on the dimensional accuracy of a press-formed product produced by press-forming a blank collected from a metal plate having shape variation.

[0019] Technical solutions to solve problems

[0020] In order to solve the problem, one embodiment of the present invention is a method for manufacturing a stamped product, which manufactures a stamped product by stamping a blank using a stamping die, wherein the blank is obtained from a metal plate with shape variation, and includes: a reference stamped product shape acquisition step, using a flat blank model with a flat shape, performing a stamping analysis of stamping using a prescribed die model, and obtaining the shape of the stamped product after demolding as the reference stamped product shape, wherein the prescribed die model is set based on the shape of the target stamped product; a waveform shaped blank stamped product shape acquisition step, generating a waveform shaped blank with a set shape based on the shape variation. A waveform blank model of a waveform shape with a wavelength and amplitude of a waveform, using the generated waveform blank model to perform stamping analysis using the set specified mold model, and obtaining the shape of the stamped product after demolding as the waveform blank stamped product shape; a first deviation amount acquisition step, comparing the reference stamped product shape with the waveform blank stamped product shape, and finding the location where the two shapes deviate and the first deviation amount as the deviation amount of the two shapes; a periodically offset waveform blank stamped product shape acquisition step, generating one or more periodically offset waveform blank models, and using the generated A periodically offset waveform shape blank model is used to perform stamping analysis of stamping using the set specified mold model, and the shape of the stamped product after demolding is obtained as the periodically offset waveform shape blank stamped product shape, wherein the periodically offset waveform shape blank model has a waveform shape with an amplitude that is the same as the waveform shape in the waveform shape blank model and a period that is offset; a second deviation amount acquisition step is used to compare the reference stamped product shape with one or more of the periodically offset waveform shape blank stamped product shapes, and to obtain a position where the two shapes deviate and a second deviation amount as the deviation amount of the deviation between the two shapes; a countermeasure unit is required A position determination step, determining a portion of the stamped product that is equivalent to a portion where a deviation of the first deviation amount exceeding a preset threshold value and a portion where a deviation of the second deviation amount exceeding a preset threshold value is generated as a portion requiring countermeasures; and a forming accuracy improvement step, correcting the shape of at least one of the forming surface of the actual mold and the actual blank selected so that the deviation at the portion requiring countermeasures determined in the step of determining the portion requiring countermeasures becomes smaller, the actual mold is a stamping mold used in the manufacture of the stamped product, and the actual blank is the blank used in the manufacture of the stamped product.

[0021] Effects of the Invention

[0022] According to the method of the present invention, the parts of the stamped product that are greatly affected by the shape change of the blank are determined based on the difference in the shape change of each blank. And by taking corresponding measures for the corresponding parts, the influence caused by the shape change of the blank can be reduced.

[0023] Thus, according to the aspect of the present invention, a press-formed product with good dimensional accuracy can be manufactured, and even when a blank collected from a metal plate with shape fluctuations is used, a press-formed product with good dimensional accuracy can be produced with a good yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an explanatory diagram of each step of the method for manufacturing a press-formed product according to the first embodiment. Figure 2 This is an external view of the target component in the first embodiment. Figure 3 This is an illustration of a flat blank model. Figure 4 It means use Figure 3 A diagram showing the reference stamped product shape obtained by performing stamping (deep drawing) 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. Figure 5 It is an explanatory diagram of the corrugated shape blank model involved in the first embodiment. Figure 6 It means use Figure 5 A diagram showing the shape of a corrugated blank stamped product obtained by performing stamping (deep drawing) analysis on a corrugated blank model and the amount of change in each part of the shape from the bottom dead point of the forming. Figure 7 It means that Figure 4 The standard stamping product shape and Figure 6 A diagram of the first deviation amount when comparing the waveform shape of the blank and the stamped product shape. Figure 8 is a vibration with amplitude Figure 5 An explanatory diagram of a period-shifted waveform shape blank model in which the waveform shape is the same as that of the waveform shape blank model and the period is shifted by 1 / 4 wavelength. Fig. 9 It means use Figure 8 A diagram showing the shape of a stamped product of a periodically offset corrugated shape blank obtained by performing stamping (deep drawing) analysis on a periodically offset corrugated shape blank model and the amount of change in each part of the shape from the bottom dead point of the forming. Fig.10 It means that Figure 4 The standard stamping product shape and Fig. 9A diagram of the second deviation amount when comparing the periodically offset waveform shape of the blank stamped product shape. Fig.11 Yes Figure 7 and Fig.10 The diagram shows the ranges of the first deviation amount and the second deviation amount in correspondence with the target shape. Fig.12 This is a diagram showing a reference stamped product shape obtained by performing stamping (deep drawing) analysis using a die model with ribs, and the amount of change in each portion of the shape from the bottom dead point of the forming. Fig.13 This is a diagram showing the shape of a corrugated blank stamped product obtained by performing stamping (deep drawing) analysis using a die model with ribs, and the amount of change in each part of the shape from the bottom dead point of the forming. Fig.14 It means that Fig.12 The standard stamping product shape and Fig.13 A diagram of the first deviation amount when comparing the waveform shape of the blank and the stamped product shape. Fig.15 This is a diagram showing the shape of a periodically offset waveform blank stamped product obtained by performing stamping (deep drawing) analysis using a die model with ribs, and the amount of change in each part of the shape from the bottom dead center of the forming. Fig.16 It means that Fig.12 The standard stamping product shape and Fig.15 A diagram of the second deviation amount when comparing the periodically offset waveform shape of the blank stamped product shape. Fig.17 Yes Fig.14 and Fig.16 The diagram shows the ranges of the first deviation amount and the second deviation amount in correspondence with the target shape. Fig.18 It means use Figure 3 A diagram showing the reference stamped product shape obtained by performing stamping forming (collision forming) analysis on a flat blank model and the amount of change in each part of the shape from the bottom dead point of forming. Fig.19 It means use Figure 5 A diagram showing the shape of a corrugated blank stamped product obtained by performing stamping forming (collision forming) analysis on a corrugated blank model and the amount of change in each part of the shape from the bottom dead point of forming. Fig. 20 It means that Fig.18 The standard stamping product shape and Fig.19 A diagram of the first deviation amount when comparing the waveform shape of the blank and the stamped product shape. Fig.21 is a vibration with amplitude Figure 5 An explanatory diagram of a period-shifted waveform shape blank model in which the waveform shape is the same as that of the waveform shape blank model and the period is shifted by 1 / 2 wavelength. Fig. 22 Shows the use of Fig.21 The periodically offset waveform shape blank model is subjected to stamping forming (collision forming) analysis to obtain the shape of the stamped product of the periodically offset waveform shape blank and the amount of change of each part of the shape from the forming bottom dead point. Fig.23 It means that Fig.18 The standard stamping product shape and Fig. 22 A diagram of the second deviation amount when comparing the periodically offset waveform shape of the blank stamped product shape. Fig.24 Yes Fig. 20 and Fig.23 The diagram shows the ranges of the first deviation amount and the second deviation amount in correspondence with the target shape. Fig.25 This is a diagram showing a reference stamped product shape obtained by performing stamping (collision forming) analysis using a die model with ribs, and the amount of change of each portion of the shape from the forming bottom dead point. Fig.26 This is a diagram showing the shape of a corrugated blank press-formed product obtained by performing press forming (collision forming) analysis using a die model with ribs, and the amount of change of each part of the shape from the forming bottom dead point. Fig. 27 It means that Fig.25 The standard stamping product shape and Fig.26 A diagram of the first deviation amount when comparing the waveform shape of the blank and the stamped product shape. Fig.28 This is a diagram showing the shape of a blank formed product having a periodically offset corrugated shape obtained by performing press forming (collision forming) analysis using a die model with ribs, and the amount of change of each portion of the shape from the forming bottom dead point. Fig.29 It means that Fig.25 The standard stamping product shape and Fig.28 A diagram of the second deviation amount when comparing the periodically offset waveform shape of the blank stamped product shape. Fig.30 Yes Fig. 27 and Fig.29 The diagram shows the ranges of the first deviation amount and the second deviation amount in correspondence with the target shape. Fig.31 It is an explanatory diagram of each step of the method for manufacturing a press-formed product according to the second embodiment. Fig.32 This is an example of an appearance diagram of a target shape to be used in the second embodiment. Fig.33 It is an explanatory diagram of a flat blank model according to the second embodiment. Fig.34 It means use Fig.33 A diagram showing the reference stamped product shape and the amount of change from the bottom dead point obtained by performing stamping analysis on a flat blank model. Fig.35 This is an explanatory diagram of a corrugated blank model. Fig.36 It means use Fig.35 A diagram showing the shape of a corrugated blank stamped product and the amount of change from the bottom dead point of the forming obtained by performing stamping analysis on a corrugated blank model. Fig.37 It means Fig.34 The standard stamping product shape and Fig.36 A diagram of the deviation amount when comparing the waveform-shaped blank with the stamped product shape. Fig.38 is a vibration with amplitude Fig.35 An explanatory diagram of a period-shifted waveform shape blank model in which the waveform shape is the same as that of the waveform shape blank model and the period is shifted by 1 / 2. Fig.39 It means use Fig.38 A diagram showing the shape of a stamped product of a periodically offset waveform shape blank and the amount of change from the bottom dead point of the forming obtained by performing stamping analysis on a periodically offset waveform shape blank model. Fig.40 It means Fig.34 The standard stamping product shape and Fig.39 A diagram of the deviation amount when comparing the periodic deviation waveform shape of the blank stamped product shape. Fig.41 Yes Fig.37 and Fig.40 A diagram showing the range of the deviation amount in correspondence with the target shape. Fig.42 It is the same as the blank model. Fig.41 A diagram in which ribs are assigned to the parts corresponding to the parts that require countermeasures and have large deviations. Fig.43 It means to use Fig.33 A diagram showing a reference stamped product shape with ribs and the amount of change from the bottom dead point of forming obtained by performing stamping analysis on a flat blank model with ribs. Fig.44 It means to use Fig.35 A graph showing the shape of a stamped product of a corrugated blank with ribs obtained by performing stamping analysis on the corrugated blank with ribs and the amount of change from the bottom dead point of forming. Fig.45 It means Fig.43 The basic stamping part shape with ribs and Fig.44 A diagram of the deviation amount when the shape of the blank stamped product is compared with the shape of the corrugated shape of the rib. Fig.46 It means to use Fig.38 A graph of the shape of the stamped product of the periodically offset waveform shape blank with ribs obtained by giving ribs to the periodically offset waveform shape blank model and the amount of change from the bottom dead point of the forming obtained by performing stamping analysis on the periodically offset waveform shape blank with ribs. Fig.47 It means Fig.43 The basic stamping part shape with ribs and Fig.46 A diagram of the deviation amount when the periodic deviation of the ribs is compared with the waveform shape of the blank stamped product shape. Fig.48 Yes Fig.45 and Fig.47 A diagram showing the range of the deviation amount in correspondence with the target shape. DETAILED DESCRIPTION

[0025] Next, embodiments of the present invention will be described with reference to the drawings.

[0026] "First Implementation Method"

[0027] The manufacturing method of the stamped product involved in this embodiment uses a blank collected from a metal plate with shape variation (convexo-concave). In this embodiment, the blank is subjected to stamping such as collision forming and deep drawing forming using a stamping die corresponding to the shape of the target stamped product to manufacture the stamped product. In the present invention, when manufacturing the stamped product, the influence of the shape variation of the blank on the manufactured stamped product is reduced, and a stamped product with higher dimensional accuracy is manufactured.

[0028] Here, the shape variation of the metal plate refers to a shape variation in which projections and depressions are continuously formed along a predetermined direction, for example.

[0029] In addition, examples of the material of the metal plate include steel and aluminum alloy, but are not limited thereto. The present invention is a technology suitable for high-strength steel plates with a tensile strength of 980 MPa or more, and particularly for ultra-high-strength steel plates with a tensile strength of 1470 MPa or more. When the tensile strength of the metal plate is high, the influence of the shape change of the metal plate or the blank on the dimensional accuracy becomes greater than when the tensile strength is low.

[0030] like Figure 1 As shown, the manufacturing method of the stamped product involved in the present embodiment includes a reference stamped product shape obtaining step S1, a corrugated blank stamped product shape obtaining step S3, a first deviation amount obtaining step S5, a periodically offset corrugated blank stamped product shape obtaining step S7, a second deviation amount obtaining step S9, a location requiring countermeasures determining step S11, a forming accuracy improving step S13 and an actual stamping forming step S15.

[0031] Mention will Figure 2 The case where the stamped product 1 shown is stamped into a target shape is taken as an example, and each structure is described in detail below. It should be noted that in this embodiment, a blank composed of a 1.5GPa grade steel plate with a plate thickness of 1.2mm and a blank model corresponding thereto are used as an example. However, the present invention is not limited to this.

[0032] <Steps for obtaining the standard stamped product shape>

[0033] The reference stamping product shape acquisition step S1 uses Figure 3 The flat blank model 3 is shown. In addition, a stamping analysis is performed using a predetermined die model to obtain the stamping product shape after demolding as a reference stamping product shape.

[0034] The prescribed die model is set based on the forming surface shape of the actual die that is used to stamp a flat blank into a target stamped product shape. For example, a die model that imitates the shape of the target stamped product shape is used as the prescribed die model. Among them, a die model that corrects the amount of springback after demolding is preferably used as the prescribed die model.

[0035] It should be noted that the “press forming analysis” in this description includes an analysis for obtaining the shape at the bottom dead point of forming and an analysis for obtaining the shape after demolding, that is, after springback.

[0036] The flat blank model 3 is a blank model generally used in conventional press forming analysis, and has a flat shape without irregularities.

[0037] The stamping analysis is usually performed by CAE analysis such as the finite element method (FEM). That is, the stamping analysis can be performed by structural analysis using a computer, such as the well-known CAE analysis. There are collision forming, deep drawing, etc. in stamping, but the present invention can be applied to any stamping. In this embodiment, the case of deep drawing is cited as an example for explanation.

[0038] The reference stamped product shape 5 after demolding obtained by stamping analysis is shown in FIG. Figure 4 .exist Figure 4 In the figure, the depth of color is used to indicate the amount of change caused by demolding from the bottom dead point of molding.

[0039] The so-called variation is the value obtained by subtracting the height of the corresponding part of the shape of the lower dead point of the forming from the height of each part of the shape of the stamped product after demolding and rebounding after stamping in the stamping direction. Therefore, the variation is a value equivalent to the rebound amount in the stamping direction. When the height difference (variation) is + (positive), the shape after demolding becomes convex compared to the shape of the lower dead point of the forming. On the other hand, when the height difference (variation) is - (negative), the shape after demolding becomes concave compared to the shape of the lower dead point of the forming.

[0040] exist Figure 4 In the molding process, the color of the concave portion compared to the lower dead point of the molding is made lighter, and the color of the convex portion is made darker. Figure 4 The numbers shown in the figure are: + is the amount of change in the convex direction (toward the front of the paper), - is the amount of change in the concave direction (toward the back of the paper), and the unit is mm. The same applies to the numbers shown in the following other figures.

[0041] In this case, Figure 4 The change amount shown. That is, the change amount of the left end (part A) of the reference stamping product shape 5 is -1.22mm. In addition, the left end (part B) of the top plate is -0.17mm. The center part in the longitudinal direction (part C) is 5.55mm. The right end (part D) of the lower flange is 2.47mm. The right end (part E) is 0.07mm.

[0042] <Steps for obtaining the shape of a corrugated blank stamped product>

[0043] The corrugated blank stamping product shape acquisition step S3 uses a blank model corresponding to the shape variation of the metal plate and performs stamping analysis similar to the reference stamping product shape acquisition step S1 to acquire the stamping product shape after demolding.

[0044] In the corrugated blank stamping product shape acquisition step S3, first, based on the shape variation of the metal plate, a corrugated blank model 7 having a shape corresponding to the shape variation of the metal plate is generated. Figure 5 (a) The specific shape is described below.

[0045] Figure 5 The corrugated blank model 7 shown in (a) is a blank model having a corrugated shape with a predetermined wavelength and a predetermined amplitude. Figure 5 The depth in (a) represents convexity and concavity. The darker part is convex toward the front of the paper, and the lighter part is concave toward the back of the paper.

[0046] Observe from the direction of the hollow arrow Figure 5 The state of (a) is Figure 5 (b), Figure 5 (b) is a partial enlarged view of Figure 5 (c). Figure 5 In the example shown, the blank has a plate thickness of 1.2 mm, an amplitude of 5.0 mm (± 2.5 mm), and a wavelength (refer to Figure 5 (d)) is a shape change of 320 mm. In addition, the starting position and the ending position of the wave shape (shape change) set in the blank do not need to be the end of the metal plate. Figure 5 (e) emphasizes Figure 5 (a) The concavity and convexity of the shape.

[0047] It should be noted that the corrugated blank model 7 can also be generated based on the measurement results by measuring the shape of the actual blank collected from a predetermined position of a metal plate with shape variation. For example, the shape of the actual blank is measured using a three-dimensional shape measuring device based on a laser rangefinder. In addition, the representative wavelength and amplitude in the measurement results can also be used as the wavelength and amplitude of the corrugated shape of the corrugated blank model 7 to generate it.

[0048] Next, using the corrugated blank model 7, a stamping analysis is performed using the same predetermined die model as in the reference stamping product shape acquisition step S1. Then, based on the analysis result, the stamping product shape after demolding is acquired as the corrugated blank stamping product shape 9. The corrugated blank stamping product shape 9 obtained by the stamping analysis is shown in FIG. Figure 6 . Figure 6 The colors and values ​​shown are the same as Figure 4 same.

[0049] In this case, Figure 6The change amount shown. That is, the change amount of the left end (part A) of the corrugated blank stamping product shape 9 is -1.05mm. The left end (part B) of the top plate is -0.39mm. The center part in the length direction (part C) is 5.57mm. The right end (part D) of the lower flange is 2.74mm. The right end (part E) is -0.22mm.

[0050] <First deviation amount acquisition step>

[0051] In the first deviation amount acquisition step S5, the reference stamped product shape 5 ( Figure 4 ) and the shape of the corrugated blank stamped product 9 ( Figure 6 Then, the position where the two shapes deviate and the first deviation amount which is the deviation amount at the deviated position are obtained.

[0052] For example, a plurality of regions are set for the shape of a stamped product, and a representative portion of each region is used as a portion for obtaining the deviation amount. For example, a region can be set as a representative region estimated to be prone to rebound after demolding. In addition, for example, the deviated portion and the first deviation amount can also be used as a group to store data.

[0053] In this embodiment, the stamped product shape at the lower dead point is used as the reference shape, and the change (springback) of the stamped product shape after demolding relative to each part of the reference shape is calculated. Then, the difference between the changes of the two stamped product shapes is calculated as the deviation.

[0054] That is, the first deviation amount obtained in the first deviation amount acquisition step S5 is the amount of change in the shape 9 of the corrugated blank stamped product ( Figure 6 ) minus the change in the standard stamped product shape 5 ( Figure 4 ) and the value obtained. The change in the shape 9 of the corrugated blank stamping product ( Figure 6 ) is the amount of change using the blank model with shape variation. The amount of change in the standard stamped product shape 5 ( Figure 4 ) is the amount of change using a flat blank model. Therefore, when the first deviation is + (positive), the corresponding portion of the waveform blank stamping product shape 9 becomes a convex shape compared to the reference stamping product shape 5. In addition, when the first deviation is - (negative), the corresponding portion of the waveform blank stamping product shape 9 becomes a concave shape compared to the reference stamping product shape 5.

[0055] The first deviation amount obtained as described above is shown in Figure 7 .

[0056] like Figure 7As shown, the first deviation of the waveform blank stamping product shape 9 from the reference stamping product shape 5 is the following value. That is, 0.17mm at the left end (part A). -0.22mm at the left end of the top plate (part B). 0.02mm at the center of the length direction (part C). 0.27mm at the right end of the lower flange (part D). -0.29mm at the right end (part E).

[0057] <Steps for obtaining the shape of a blank stamped product with a periodically offset waveform shape>

[0058] The periodically offset corrugated blank stamped product shape acquisition step S7 uses a corrugated blank model having a shape different from the corrugated blank model 7 and performs stamping analysis similar to the reference stamped product shape acquisition step S1 to acquire the stamped product shape after demolding.

[0059] In the periodically offset waveform blank stamping product shape acquisition step S7, first, a periodically offset waveform blank model 11 is generated, wherein the periodically offset waveform blank model 11 has a waveform shape having the same wavelength and amplitude as the waveform shape in the waveform blank model 7 and having a period offset. An example of the periodically offset waveform blank model 11 is shown in FIG. Figure 8 (a) The specific shape is described below.

[0060] 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 depth in (a) represents the concavity and convexity.

[0061] Observe from the direction of the hollow arrow Figure 8 The state of (a) is Figure 8 (b), Figure 8 (b) is a partial enlarged view of Figure 8 (c). Figure 8 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 waveform shape blank model 7 is the same. However, the period of the waveform shape is shifted to the right of the paper by 1 / 4 wavelength (refer to Figure 8 (d) Figure 8 (e)).

[0062] In addition, the shift of the set period is not limited to the 1 / 4 wavelength.

[0063] Next, using the periodic offset waveform shape blank model 11, a stamping analysis is performed when stamping is performed using the same predetermined die model as in the reference stamping product shape acquisition step S1. Then, the stamping product shape after demolding is obtained as the periodic offset waveform shape blank stamping product shape 13. The periodic offset waveform shape blank stamping product shape 13 is shown in Fig. 9 . Fig. 9 The colors and values ​​shown are the same as Figure 4 , Figure 6 same.

[0064] In this case, Fig. 9 The change amount shown. That is, the change amount of the left end (part A) of the periodically offset waveform blank stamping product shape 13 is -0.64mm. The left end (part B) of the top plate is 0.03mm. The center part in the length direction (part C) is 5.66mm. The right end (part D) of the lower flange is 2.78mm. The right end (part E) is -0.28mm.

[0065] <Second deviation amount acquisition step>

[0066] In the second deviation amount acquisition step S9, the reference stamped product shape 5 is compared with the periodically offset waveform blank stamped product shape 13. And, it is a step of obtaining the second deviation amount as the deviation amount at the position where the two shapes deviate and the deviation amount at each deviated position. 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.

[0067] The standard stamped product shape 5 ( Figure 4 ) and the periodically offset waveform shape blank stamping product shape 13 ( Fig. 9 ) is compared with the second deviation value shown in Fig.10 .

[0068] like Fig.10 As shown, the second deviation of the periodically offset waveform blank stamping product shape 13 from the reference stamping product shape 5 is the following value. That is, 0.58mm at the left end (part A). 0.20mm at the left end of the top plate (part B). 0.11mm at the center of the length direction (part C). 0.31mm at the right end of the lower flange (part D). -0.35mm at the right end (part E).

[0069] <Steps for determining areas requiring countermeasures>

[0070] The countermeasure-requiring portion identifying step S11 is a step of identifying portions of the stamped product 1 corresponding to portions having the first deviation exceeding the threshold value in the first deviation obtaining step S5 and portions having the second deviation exceeding the threshold value in the second deviation obtaining step S9 as countermeasure-requiring portions.

[0071] For example, in the case of assembling a plurality of stamped parts to a vehicle body by overlapping and joining them, if the shapes of the stamped parts (especially the flange parts, etc.) deviate greatly, it becomes difficult to join the stamped parts to each other. In such a case, countermeasures are sometimes required. Therefore, in this embodiment, the parts that are assumed to be greatly affected by the shape change of the blank, that is, the parts with large deviations, are determined as the parts that require countermeasures. In addition, countermeasures are taken to reduce the influence caused by the shape change of the blank.

[0072] 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 ) These two correspond to the stamped product 1 and are shown in Fig.11 .

[0073] like Fig.11 As shown, the first deviation and the second deviation are as follows. That is, at part A, it is 0.17 mm to 0.58 mm. At part B, it is -0.22 mm to 0.20 mm. At part C, it is 0.02 mm to 0.11 mm. At part D, it is 0.27 mm to 0.31 mm. At part E, it is -0.35 mm to -0.29 mm.

[0074] exist Fig.11 In the figure, for each part, the minimum range including the first deviation and the second deviation is shown as the range of the deviation that may occur in each part. In this example, one second deviation is obtained for each part, but when two or more second deviations are obtained, for each part, the minimum range including one first deviation and two or more second deviations is used as the range of the deviation that may occur in each part.

[0075] For example, if the threshold in the measure-required site identification step S11 is set to ±0.20 mm, the sites where the deviation exceeds the threshold is site A, site B, site D, and site E. These sites are then identified as the measure-required sites.

[0076] In this embodiment, as a countermeasure for reducing the influence of the shape change of the blank, a rib is added to the portion of the actual die surface corresponding to the portion requiring the countermeasure. The countermeasure for reducing the influence of the shape change of the blank is equivalent to the forming accuracy improvement step S13. Then, the actual die with the rib added is used for stamping.

[0077] <Steps to improve molding accuracy>

[0078] In the forming accuracy improvement step S13, a correction process is performed to reduce the above-mentioned deviation at the position requiring countermeasures determined in the position requiring countermeasures determination step S11. That is, a process of correcting the shape of at least one of the shapes selected from the forming surface of the actual die, i.e., the stamping die used in the manufacture of the stamped product, and the actual blank, i.e., the blank used in the manufacture of the stamped product, is performed.

[0079] In the forming accuracy improvement step of the present embodiment, in order to reduce the influence of the shape variation of the blank, the forming surface of the actual die used in the press forming is corrected. Therefore, the forming accuracy improvement step S13 of the present embodiment includes a rib providing step S13A.

[0080] The rib-adding step S13A is a step of adding the above-mentioned ribs to the actual mold. The ribs are added to the portion of the actual mold surface that requires countermeasures for forming, or to the portion that requires countermeasures for forming and its surrounding portion.

[0081] It should be noted that when the rib marks 22 are formed in the stamped product, Figure 12 to Figure 16 It is advisable to give ribs to the actual mold, just like the rib marks 22 formed at the parts B, D, and E of the stamping. In addition, it is advisable to give ribs to the actual mold in such a way that the length direction of the rib marks 22 becomes a direction that intersects with the end edge of the stamped product. By forming such rib marks 22, the rigidity of the end of the stamped product can be improved, and the wave shape (shape change) from the blank residue before stamping to the stamped product can be suppressed, thereby further improving the dimensional accuracy.

[0082] Therefore, in the rib imparting step S13A, it is preferable to impart ribs to the actual mold in such a manner that the length direction of the rib mark 22 becomes a direction intersecting with the end edge closest to the portion requiring countermeasures in the stamped product 1. However, in the case where it is not possible to set the rib at the end edge closest to the portion requiring countermeasures due to reasons such as the design of the component, the rib is set near a location that can be set, such as near the portion requiring countermeasures.

[0083] In addition, when a blank having a continuous concavo-convex shape change is subjected to stamping as in the present embodiment, ribs may be provided to the actual die in such a manner that the length direction of the rib mark 22 is along the direction of the continuous concavo-convex shape change. By providing such ribs to the actual die, the shape change of the blank can be suppressed by the ribs of the actual die near the lower dead point during stamping. As a result, a stamped product can be obtained in a state where the shape change is suppressed, thereby improving dimensional accuracy.

[0084] Therefore, in the rib imparting step S13A, it is advisable to impart ribs to the actual mold as follows. That is, as described above, it is advisable to impart ribs to the actual mold in such a manner that the length direction of the rib marks is along the direction of the continuous concave-convex shape changes of the blank at the part of the stamped product that requires countermeasures or at a part nearby. Here, it is preferred to impart ribs in such a manner that the length direction of the rib marks is along the direction of the continuous concave-convex shape changes of the blank at the part of the stamped product that requires countermeasures. However, in the case where it is impossible to impart ribs to the part that requires countermeasures due to reasons such as the design of the component, for example, the rib marks may be imparted in such a manner that the length direction of the rib marks is along the direction of the continuous concave-convex shape changes of the blank at a part nearby the part of the stamped product that requires countermeasures.

[0085] It should be noted that the length of the line in the direction in which the concavities and convexities of the blank with shape variation is longer depending on the amplitude. Figure 3 Flat blank model 3 and Figure 5 In the case of the corrugated blank model 7 , the direction in which the concavities and convexities of the corrugated blank model 7 are continuous, that is, the line length from the left end to the right end is longer than that of the flat blank model 3 .

[0086] In such a case, it is advisable to obtain the difference between the line length of the blank and the line length of the blank without shape change, and to give ribs to the actual die in a manner that forms rib marks to correct the line length difference. By giving such ribs, the dimensional accuracy of the stamped product can be further improved.

[0087] In addition, the rib marks formed in the parts requiring countermeasures can be convex or concave. The length, width, and height of the rib marks should be appropriately determined based on the allowable height and spacing of the wavy shape (shape change) remaining in the stamped product, depending on the allowable degree of shape required for the target stamped product.

[0088] In addition, as the shape of the rib mark, a circle, an ellipse, an oval, a square, a rectangle, a triangle, a rhombus, etc. can be applied when viewed from above, and a mountain shape, a trapezoid, a semicircle, a semi-ellipse, etc. can be applied when viewed from the side.

[0089] Here, the shape of the rib mark is the same as the shape of the rib given to the actual mold.

[0090] <Actual stamping steps>

[0091] The actual press forming step S15 is a step of press forming the actual blank using the actual die to which the ribs were provided in the rib providing step S13A.

[0092] <Confirmation of the effect of rib formation>

[0093] Here, the effect of stamping by using an actual die with ribs was confirmed by stamping analysis. The confirmation content is described below.

[0094] Here, ribs are added to the parts of the predetermined die model used in the above-mentioned stamping analysis that correspond to the parts that need countermeasures. Then, using the die model based on the actual die with ribs added (hereinafter referred to as the "die model with ribs added"), the same analysis as the reference stamping product shape acquisition step S1 to the second deviation amount acquisition step S9 is performed. It should be noted that 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 .

[0095] Apply ribs to the die model and apply them to the flat blank model 3 (refer to Figure 3 ) The reference stamping product shape 21 obtained by performing stamping analysis is shown in Fig.12 .

[0096] like Fig.12 As shown, the rib shape of the rib-giving die model is transferred to the reference stamping product shape 21, forming a rib mark 22. Fig.12 As shown in the enlarged view of FIG. 1 , the portion of the actual mold corresponding to the portion A is provided with ribs. Specifically, the ribs are provided in a manner that the length direction of the rib marks 22 transferred to the blank is along the direction in which the concave and convex of the shape change of the blank is continuous. Furthermore, the ribs are provided in a manner parallel to the left end side of the stamped product 1.

[0097] In addition, ribs are provided at the portions corresponding to the portions B, D, and E of the die model so that the longitudinal direction of the rib marks 22 intersects with the edge closest to the corresponding portion in the press-formed product 1 .

[0098] like Fig.12 As shown, the amount of change is as follows. That is, the amount of change of the part A of the reference stamping product shape 21 when the stamping analysis is performed using the rib-giving die model is 0.07 mm. Part B is -0.04 mm. Part C is 5.50 mm. Part D is 2.52 mm. Part E is -0.82 mm.

[0099] Next, the rib-imparting die model is used to form a corrugated blank model 7 (refer to Figure 5 ) The shape of the waveform blank stamped product 23 obtained by stamping analysis is shown in Fig.13 .

[0100] like Fig.13 As shown, the changes are as follows. That is, the changes in the portion A of the corrugated blank stamping product shape 23 are 0.14 mm. The portion B is -0.07 mm. The portion C is 5.55 mm. The portion D is 2.54 mm. The portion E is -0.84 mm.

[0101] The reference stamped product shape 21 ( Fig.12 ) and the shape of the corrugated blank stamped product 23 ( Fig.13 ) is shown in Fig.14 .

[0102] like Fig.14 As shown, the first deviation amount of the reference stamping product shape 21 and the waveform blank stamping product shape 23 when the stamping analysis is performed using the rib-giving die model is as follows. That is, it is 0.07mm at part A, -0.03mm at part B, 0.05mm at part C, 0.02mm at part D, and -0.02mm at part E.

[0103] Next, the periodically offset waveform shape blank model 11 (refer to Figure 8 ) The periodic offset waveform shape blank stamping product shape 25 obtained by stamping forming analysis is shown in Fig.15 .

[0104] like Fig.15 As shown, the variation is as follows. That is, the variation of the portion A of the periodically offset wave-shaped blank stamping product shape 25 is 0.10 mm. In addition, the portion B is -0.07 mm, the portion C is 5.55 mm, the portion D is 2.65 mm, and the portion E is -0.79 mm.

[0105] The reference stamped product shape 21 ( Fig.12 ) and the periodic offset waveform shape blank stamping product shape 25 ( Fig.15 The second deviation obtained by comparison is shown in Fig.16 .

[0106] like Fig.16As shown, the second deviation amount between the reference stamped product shape 21 and the periodically offset waveform blank stamped product shape 25 is as follows: 0.03 mm at part A, -0.03 mm at part B, 0.05 mm at part C, 0.13 mm at part D, and 0.03 mm at part E.

[0107] make Fig.14 The first deviation and Fig.16 The second deviation amount and the second deviation amount are shown in FIG. Fig.17 .

[0108] like Fig.17 As shown, the first deviation amount and the second deviation amount are as follows: that is, 0.03 mm to 0.07 mm at the portion A, -0.03 mm at the portion B, 0.05 mm at the portion C, 0.02 mm to 0.13 mm at the portion D, and -0.02 mm to 0.03 mm at the portion E. Fig.17 The deviation from Fig.11 The deviation amount before the countermeasure shown is significantly smaller than that before the countermeasure is shown. Therefore, it can be confirmed that the use of the corrected rib-imparting die model has the effect of reducing the influence of the shape variation of the blank.

[0109] Thus, when the actual blank with shape variation is stamped using the corrected actual die with ribs, the shape of the stamped product after stamping is obtained. Fig.17 That is, the influence of the shape change of the blank is reduced, and good dimensional accuracy is obtained.

[0110] As described above, according to the present embodiment, it is possible to identify the portion that is greatly affected by the shape variation of the blank and take appropriate measures, thereby stably obtaining a press-formed product with good dimensional accuracy.

[0111] It should be noted that in this embodiment, a plurality of patterns are generated from a blank model assuming a blank with shape variation, and the deviation amount in each case is calculated to determine the location requiring countermeasures. Therefore, the difference in shape variation occurring between actual blanks is taken into account.

[0112] It should be noted that, although only one periodic offset waveform blank model is generated, multiple periodic offset waveform blank models can also be generated. In this case, the waveform of the periodic offset waveform blank model is preferably such that the periods are offset from each other. However, the wavelength and amplitude are common in the waveform blank model and all periodic offset waveform blank models.

[0113] By increasing the pattern of the blank model assuming a blank with shape fluctuation, it is possible to more specifically consider the difference in shape fluctuation that occurs between actual blanks.

[0114] In the above description, when the deviation between the shapes of two stamped products is determined, the difference in the amount of change (springback) from the bottom dead point in the stamping direction is taken as the deviation. However, the present invention is not limited to this.

[0115] For example, in the stamping direction, the height of each part of the stamping product shape after demolding (after springback) is obtained. Then, the difference obtained by subtracting the height of each part of the stamping product shape after demolding (after springback) from the height of each part can be set as the deviation amount.

[0116] However, in this case, it is necessary to set a common fixed point for the two press-formed product shapes, and the amount of deviation may vary depending on the method of selecting the fixed point.

[0117] In this regard, it is preferable to compare the variation amounts based on the shape at the bottom dead point of forming which is constant regardless of the presence or absence of shape variation of the blank as in the present embodiment because the deviation amount can be accurately and easily obtained.

[0118] In addition, the actual stamping step S15 may also include the following coining process when stamping is performed using the corrected actual mold. That is, it may also include a coining process of re-punching the stamped product with the rib marks 22 transferred from the actual mold to which the ribs are given to crush the rib marks 22. By crushing the rib marks 22 in the coining process, strain is applied to the rib marks 22 and their surroundings to perform work hardening, and the rigidity of the stamped product is further improved. In addition, the wave shape (shape change) remaining from the blank before stamping to the stamped product can be suppressed, thereby further improving the dimensional accuracy.

[0119] It should be noted that in the present invention, it is not necessary to form clear rib marks on the stamped product. For example, there is a case where the height of the ribs given to the actual mold is low, and the stamped product does not have clear rib marks transferred. However, in this case, stamping can be performed in a state where the ribs of the actual mold suppress the shape change of the blank, so the influence caused by the shape change of the blank can be reduced.

[0120] (Example)

[0121] In order to confirm the effect of the first embodiment, Figure 1 A method for manufacturing a stamped product as described in .

[0122] In this embodiment, similarly to the first embodiment, Figure 2The stamped product 1 is set as the target shape. In addition, regarding the forming method in the stamping forming analysis, the embodiment is deep drawing, while in this embodiment, it is collision forming. It should be noted that the change amount and deviation amount in this embodiment are obtained by the same method as the first embodiment.

[0123] First, in the reference stamping product shape acquisition step S1, a flat blank model 3 (see Figure 3 ) for stamping analysis. Then, the stamping product shape after demolding is obtained as the reference stamping product shape 31. It is shown in Fig.18 .

[0124] like Fig.18 As shown, the change amount of the part A of the reference stamped product shape 31 when the stamping analysis is performed using a predetermined die model is 1.06 mm. In addition, the part B is 0.63 mm, the part C is 6.02 mm, the part D is 1.10 mm, and the part E is -2.61 mm.

[0125] Next, in the step S3 of obtaining the shape of the corrugated blank stamped product, the same predetermined die model as above is used to obtain the shape of the corrugated blank stamped product. Figure 5 The waveform blank model 7 is subjected to stamping analysis. The waveform blank stamping product shape 33 as the stamping product shape after demolding is shown in FIG. Fig.19 .

[0126] like Fig.19 As shown, the change amount of the part A of the corrugated blank stamping product shape 33 when the stamping analysis is performed using a predetermined die model is 1.37 mm. In addition, the part B is 0.72 mm, the part C is 6.02 mm, the part D is 0.96 mm, and the part E is -2.11 mm.

[0127] Then, in the first deviation amount acquisition step S5, the reference stamped product shape 31 ( Fig.18 ) and the shape of the corrugated blank stamped product 33 ( Fig.19 ) are compared. Then, the deviation between the two shapes (first deviation) is calculated.

[0128] like Fig. 20 As shown, the first deviation amount of the corrugated blank stamped product shape 33 from the reference stamped product shape 31 is as follows: 0.31 mm at part A, 0.09 mm at part B, 0.00 mm at part C, -0.14 mm at part D, and 0.50 mm at part E.

[0129] Next, in the periodically offset corrugated blank stamping product shape acquisition step S7, a corrugated blank model having a shape different from the corrugated blank model 7 is generated. Then, stamping analysis is performed using the same predetermined die model as above to acquire the stamping product shape after demolding.

[0130] As a corrugated blank model having a shape different from the corrugated blank model 7, a corrugated blank model having a shape different from the corrugated blank model 7 is used in the embodiment. Figure 8 The periodic offset waveform shape blank model 11 described in the embodiment. However, in this embodiment, Fig.21 The periodically shifted corrugated shape blank model 41 is shown. The specific shape of the periodically shifted corrugated shape blank model 41 will be described below.

[0131] Fig.21 The example shown is a blank model having a periodic wave shape having a prescribed wavelength and a prescribed amplitude. Fig.21 The depth in (a) represents the concavity and convexity.

[0132] Observe from the direction of the hollow arrow Fig.21 The state of (a) is Fig.21 (b). Fig.21 (b) is a partial enlarged view of Fig.21 (c). Fig.21 In the example shown, the plate thickness is 1.2 mm, and the amplitude and wavelength of the concave and convex are Figure 5 However, in this embodiment, the period of the waveform is shifted to the right of the paper by 1 / 2 wavelength (refer to Fig.21 (d) Fig.21 (e)).

[0133] The specified mold model will be used Fig.21 The periodic offset waveform shape blank model 41 is subjected to stamping analysis, and the periodic offset waveform shape blank stamping product shape 43 is shown in FIG. Fig. 22 .

[0134] like Fig. 22 As shown, the change amount of the periodic deviation waveform blank stamping product shape 43 in the case of stamping analysis using a predetermined die model is 0.85mm. In addition, the change amount of the portion A is 0.88mm, the portion C is 5.95mm, the portion D is 0.86mm, and the portion E is -2.58mm.

[0135] Then, in the second deviation amount acquisition step S9, the reference stamped product shape 31 ( Fig.18 ) and the periodically offset waveform shape blank stamping product shape 43 ( Fig. 22Then, the deviation (second deviation) is calculated.

[0136] like Fig.23 As shown, the second deviation amount of the periodically offset waveform blank stamped product shape 43 from the reference stamped product shape 31 is as follows: that is, -0.21 mm at part A, 0.25 mm at part B, -0.07 mm at part C, -0.24 mm at part D, and 0.03 mm at part E.

[0137] The first deviation amount ( Fig. 20 ) and the second deviation amount ( Fig.23 ) These two correspond to the stamped product 1 and are shown in Fig.24 .

[0138] like Fig.24 As shown, the deviation amounts before the countermeasures were as follows: -0.21 mm to 0.31 mm at site A, 0.09 mm to 0.25 mm at site B, -0.07 mm to 0.00 mm at site C, -0.24 mm to -0.14 mm at site D, and 0.03 mm to 0.50 mm at site E.

[0139] Here, for example, the threshold in the measure-required site determination step S11 is set to ±0.20 mm. In this case, the sites where the deviation exceeds the threshold is site A, site B, site D, and site E. Therefore, these sites are determined as the measure-required sites.

[0140] In this embodiment, as a countermeasure for reducing the influence of the shape variation of the blank, the surface of the actual mold corresponding to the above-mentioned countermeasure-required portion is also given the same ribs as in the embodiment. In this embodiment, the effect is confirmed by stamping analysis, so it is described below.

[0141] Here, similarly to the embodiment, ribs are added to a predetermined die model, and this die model (rib adding die model) is used. Then, the same analysis as the reference stamped product shape acquisition step S1 to the second deviation amount acquisition step S9 is performed.

[0142] Apply ribs to the die model and apply them to the flat blank model 3 (refer to Figure 3 ) The reference stamping product shape 51 obtained by performing stamping analysis is shown in Fig.25 .

[0143] like Fig.25As shown, the variation of the portion A of the reference stamped product shape 51 when the rib providing die model is used is 1.29 mm, the portion B is 0.07 mm, the portion C is 6.50 mm, the portion D is 2.10 mm, and the portion E is 1.80 mm.

[0144] Next, the rib-imparting die model is used to form a corrugated blank model 7 (refer to Figure 5 ) The shape of the waveform blank stamped product 53 obtained by stamping forming analysis is shown in Fig.26 .

[0145] like Fig.26 As shown, the change amount of the portion A of the corrugated blank stamping product shape 53 when the rib-providing die model is used is 1.38 mm. In addition, the portion B is 0.08 mm, the portion C is 6.50 mm, the portion D is 1.93 mm, and the portion E is 1.86 mm.

[0146] The reference stamped product shape 51 ( Fig.25 ) and the shape of the corrugated blank stamped product 53 ( Fig.26 ) is shown in Fig. 27 .

[0147] like Fig. 27 As shown, the first deviation between the reference stamping product shape 51 and the waveform blank stamping product shape 53 when the rib-imparting die model is used is as follows. That is, it is 0.09 mm at part A, 0.01 mm at part B, 0.00 mm at part C, -0.17 mm at part D, and 0.06 mm at part E.

[0148] Next, the periodically offset waveform shape blank model 41 (refer to Fig.21 ) The periodic offset waveform shape blank stamping product shape 55 obtained by stamping forming analysis is shown in Fig.28 .

[0149] like Fig.28 As shown, the change amount of the periodically offset corrugated blank stamping product shape 55 in the case of using the rib providing die model is 1.29 mm at part A. In addition, part B is 0.19 mm, part C is 6.45 mm, part D is 1.97 mm, and part E is 1.85 mm.

[0150] The reference stamped product shape 51 ( Fig.25 ) and the periodically offset waveform shape blank stamping product shape 55 ( Fig.28 The second deviation obtained by comparison is shown in Fig.29 .

[0151] like Fig.29 As shown, the second deviation amount of the reference stamping product shape 51 and the periodic offset waveform blank stamping product shape 55 when the rib-imparting die model is used is as follows. That is, it is 0.00mm at part A, 0.12mm at part B, -0.05mm at part C, -0.13mm at part D, and 0.05mm at part E.

[0152] make Fig. 27 The first deviation and Fig.29 The second deviation amount and the second deviation amount are shown in FIG. Fig.30 .

[0153] like Fig.30 As shown, the deviation amount when using the rib-imparting die model is as follows: 0.00 mm to 0.09 mm at part A, 0.01 mm to 0.12 mm at part B, -0.05 mm to 0.00 mm at part C, -0.17 mm to -0.13 mm at part D, and 0.05 mm to 0.06 mm at part E. Fig.30 The deviation from Fig.24 Therefore, it can be confirmed that by providing ribs to the die corresponding to the portion requiring countermeasures, the effect of reducing the influence of the shape change of the blank is also achieved in the case of collision forming.

[0154] Therefore, in the rib imparting step S13A, the same ribs as those in the rib imparting mold model are imparted to the actual mold surface. Specifically, ribs are imparted to the portion requiring countermeasures for forming in this embodiment, or to the portion requiring countermeasures for forming and the surrounding portions of the mold.

[0155] Then, in the actual stamping step S15, the actual blank with the shape variation is stamped using the actual die with the ribs. It should be noted that the actual blank uses a 1.5 GPa grade steel plate with a thickness of 1.2 mm, which corresponds to the above-mentioned blank model.

[0156] In this embodiment, the shape of the stamped product obtained by stamping in the actual stamping step S15 is similar to Fig.30 Similarly to the analysis results, the influence of the shape variation of the blank is reduced, and good dimensional accuracy is obtained.

[0157] "Second Implementation Method"

[0158] Next, a second embodiment of the present invention will be described with reference to the drawings.

[0159] In addition, in the second embodiment, the same structures and components as those in the first embodiment are denoted by the same reference numerals and described.

[0160] The manufacturing method of the stamped product involved in this embodiment uses a blank collected from a metal plate with shape variation (concave and convex). In addition, it is a method for reducing the influence of the shape variation of the blank during stamping such as collision forming and deep drawing forming, and improving the dimensional accuracy of the stamped product.

[0161] Specifically, if Fig.31 As shown, the manufacturing method of the stamped product involved in this embodiment includes a reference stamped product shape acquisition step S1, a corrugated blank stamped product shape acquisition step S3, a first deviation amount acquisition step S5, a periodically offset corrugated blank stamped product shape acquisition step S7, a second deviation amount acquisition step S9, a location requiring countermeasures determination step S11, a forming accuracy improvement step S23 and a rib-giving actual blank stamping step S25.

[0162] The structures of the reference stamped product shape obtaining step S1, the corrugated blank stamped product shape obtaining step S3, the first deviation amount obtaining step S5, the periodically offset corrugated blank stamped product shape obtaining step S7, the second deviation amount obtaining step S9 and the step S11 of determining the part requiring countermeasures are respectively the same as the steps described in the first embodiment.

[0163] In this example, Fig.32 The stamped product 1 shown is stamped into a target shape as an example, and each step is described in detail below. It should be noted that 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.

[0164] <Steps for obtaining the standard stamped product shape>

[0165] In the reference stamped product shape acquisition step S1, as described in the first embodiment, the reference stamped product shape acquisition step S2 is performed using Fig.33 The flat blank model 3 shown is subjected to stamping analysis using a predetermined die model, and the stamping product shape after demolding is obtained as a reference stamping product shape.

[0166] The press forming may be collision forming or stretch forming, etc., and is not particularly limited. In the second embodiment, the case where the press forming is collision forming is described as an example.

[0167] The standard stamped product shape 5 after demolding based on stamping analysis is shown in FIG. Fig.34 .exist Fig.34In addition to the shape, the amount of change from the bottom dead point of forming is also expressed by the depth of color.

[0168] The definition of the amount of change and the like in this embodiment is the same as that described in the first embodiment.

[0169] In this example, if Fig.34 As shown, the change amount of the left end (part A) of the reference stamping product shape 5 is 1.06mm. In addition, the left end (part B) of the top plate is 0.63mm, the longitudinal center (part C) is 6.02mm, the right end (part D) of the lower flange is 1.10mm, and the right end (part E) is -2.61mm.

[0170] <Steps for obtaining the shape of a corrugated blank stamped product>

[0171] The corrugated 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.

[0172] In the corrugated blank stamping product shape acquisition step S3, first, a corrugated blank model 7 of a shape corresponding to the shape variation of the metal plate, for example, a concave and convex corrugated shape, is generated. An example of the corrugated blank model 7 is shown in FIG. Fig.35 (a) The specific shape is described below.

[0173] Fig.35 The example shown in (a) is a blank model having a waveform shape with a predetermined wavelength and a predetermined amplitude. Fig.35 The depth in (a) represents the concavity and convexity. The darker part is convex toward the front of the paper, while the lighter part is concave toward the back of the paper.

[0174] Observe from the direction of the hollow arrow Fig.35 The state of (a) is Fig.35 (b) The enlarged image of a part of it is Fig.35 (c). Fig.35 The blank of the example shown has a plate thickness of 1.2 mm, a wave (concavity and convexity) amplitude of 5.0 mm (±2.5 mm), and a wavelength of concavity and convexity (refer to Fig.35 (d)) is a 320 mm wave shape. In addition, the starting position and the ending position of the concave and convex set on the blank do not need to be the end of the blank. It should be noted that Fig.35 (e) emphasizes Fig.35 (a) The concave and convex parts of the shape.

[0175] It should be noted that the corrugated blank model 7 may be generated as described in the first embodiment.

[0176] Next, using the corrugated blank model 7, a stamping analysis is performed when stamping is performed using the same predetermined die model as in the reference stamping product shape acquisition step S1. Then, based on the analysis result, the stamping product shape after demolding is obtained as the corrugated blank stamping product shape 9. The corrugated blank stamping product shape 9 obtained by the stamping analysis is shown in FIG. Fig.36 . Fig.36 The colors and values ​​shown have the same meaning as Fig.34 same.

[0177] In this example, if Fig.36 As shown, the change amount of the left end (part A) of the corrugated blank stamping product shape 9 is 1.37mm. In addition, the left end (part B) of the top plate is 0.72mm, the central part in the length direction (part C) is 6.02mm, the right end (part D) of the lower flange is 0.96mm, and the right end (part E) is -2.11mm.

[0178] <First deviation amount acquisition step>

[0179] In the first deviation amount acquisition step S5, the reference stamped product shape 5 ( Fig.34 ) and the shape of the corrugated blank stamped product 9 ( Fig.36 ) for comparison. And, it is a step to find the position and amount of deviation between the two shapes.

[0180] In this embodiment, the stamped product shape at the lower dead point of the stamping is used as the reference shape, and the change (springback) of the stamped product shape after demolding relative to each part of the reference shape is calculated. Then, the difference between the changes in the shapes of the two stamped products is calculated as the deviation.

[0181] That is, the deviation amount obtained in the first deviation amount acquisition step S5 is the amount of change in the shape 9 of the corrugated blank stamped product ( Fig.36 ) minus the change in the standard stamped product shape 5 ( Fig.34 ) and the value obtained. The change in the shape 9 of the corrugated blank stamping product ( Fig.36 ) is the amount of change using the blank model with shape variation. The amount of change in the standard stamped product shape 5 ( Fig.34) is the amount of change using a flat blank model. Therefore, when the deviation is + (positive), the corresponding portion of the waveform blank stamping product shape 9 becomes a convex shape compared to the reference stamping product shape 5. In addition, when the deviation is - (negative), the corresponding portion of the waveform blank stamping product shape 9 becomes a concave shape compared to the reference stamping product shape 5.

[0182] The deviation amount obtained as described above is shown in correspondence with the shape 9 of the corrugated blank press-formed product. Fig.37 .

[0183] like Fig.37 As shown, the deviations of the corrugated blank stamped product shape 9 from the reference stamped product shape 5 are as follows: 0.31 mm at part A, 0.09 mm at part B, 0.00 mm at part C, -0.14 mm at part D, and 0.50 mm at part E.

[0184] <Steps for obtaining the shape of a blank stamped product with a periodically offset waveform shape>

[0185] The periodically shifted corrugated blank stamped product shape acquisition step S7 is a step of performing stamping analysis using a corrugated blank model having a shape different from the corrugated blank model 7. Then, it is a step of acquiring the shape of the stamped product after demolding based on the analysis result.

[0186] In the periodically offset waveform blank stamping product shape acquisition step S7, first, a periodically offset waveform blank model 11 is generated, wherein the periodically offset waveform blank model 11 has a waveform shape having the same wavelength and amplitude as the waveform shape in the waveform blank model 7 and having a period offset. An example of the periodically offset waveform blank model 11 is shown in FIG. Fig.38 (a). Its specific shape is described below.

[0187] Fig.38 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. Fig.38 The depth in (a) represents the concavity and convexity.

[0188] Observe from the direction of the hollow arrow Fig.38 The state of (a) is Fig.38 (b) Fig.38 (b) is a magnified portion of the image. Fig.38 (c). Fig.38 In the example shown, the plate thickness is 1.2 mm, and the amplitude and wavelength of the concave and convex are Fig.35However, in this example, the period of the waveform is shifted to the right of the paper by 1 / 2 wavelength compared to the waveform blank model 7 (refer to Fig.38 (d) Fig.38 (e)).

[0189] Next, the periodic offset waveform shape blank model 11 is used to perform stamping analysis using the same predetermined die model as in the reference stamping product shape acquisition step S1. Then, the stamping product shape after demolding is obtained as the periodic offset waveform shape blank stamping product shape 13. The periodic offset waveform shape blank stamping product shape 13 is shown in FIG. Fig.39 . Fig.39 The colors and values ​​shown have the same meaning as Fig.34 , Fig.36 same.

[0190] In this example, if Fig.39 As shown, the change amount of the left end (part A) of the periodically offset waveform blank stamping product shape 13 is 0.85mm. In addition, the left end (part B) of the top plate is 0.88mm, the central part in the length direction (part C) is 5.95mm, the right end (part D) of the lower flange is 0.86mm, and the right end (part E) is -2.58mm.

[0191] <Second deviation amount acquisition step>

[0192] The second deviation amount acquisition step S9 is a step of comparing the reference stamped product shape 5 with the periodically offset waveform blank stamped product shape 13 to find the deviation position and deviation amount of the two shapes. The method for finding the deviation amount is the same as the method described in the first deviation amount acquisition step S5, so the description is omitted.

[0193] The standard stamped product shape 5 ( Fig.34 ) and the periodically offset waveform shape blank stamping product shape 13 ( Fig.39 The deviation between the two at this time corresponds to the blank stamping product shape 13 of the periodic offset waveform shape. Fig.40 .

[0194] like Fig.40 As shown, the deviations of the periodically offset waveform blank stamped product shape 13 from the reference stamped product shape 5 are as follows: -0.21 mm at part A, 0.25 mm at part B, -0.07 mm at part C, -0.24 mm at part D, and 0.03 mm at part E.

[0195] <Steps for determining areas requiring countermeasures>

[0196] The measure-required portion specifying step S11 is a step of specifying, as a measure-required portion, a portion having a deviation exceeding a threshold value among the deviations obtained in the first deviation obtaining step S5 and the second deviation obtaining step S9 .

[0197] For example, in the case of assembling a plurality of stamped parts to a vehicle body by overlapping and joining them, if the shapes of the stamped parts (especially flange parts, etc.) deviate greatly, it becomes difficult to join the stamped parts to each other. In this case, countermeasures are sometimes required. Therefore, in this embodiment, a portion that is assumed to be greatly affected (largely deviated) by the shape change of the blank is determined as a portion requiring countermeasures, and countermeasures are taken to reduce the influence.

[0198] The deviation amount (see Fig.37 ) and the deviation amount obtained in the second deviation amount acquisition step S9 (refer to Fig.40 ) and the target shape (stamped product 1) are shown in FIG. Fig.41 .

[0199] like Fig.41 As shown, the deviation amounts are as follows: -0.21 mm to 0.31 mm at part A, 0.09 mm to 0.25 mm at part B, -0.07 mm to 0.00 mm at part C, -0.24 mm to -0.14 mm at part D, and 0.03 mm to 0.50 mm at part E.

[0200] For example, the threshold in the countermeasure-required portion determination step S11 is set to ±0.15 mm. In this case, the portions where the deviation exceeds the threshold is portion A, portion B, portion D, and portion E. Therefore, these portions are determined as the countermeasure-required portions in the stamped product shape.

[0201] <Steps to improve molding accuracy>

[0202] The forming accuracy improvement step S23 is a step of performing correction processing to reduce the above-mentioned deviation at the position requiring countermeasures determined in the position requiring countermeasures determination step S11. Specifically, a process of correcting the shape of at least one of the shapes selected from the forming surface of the stamping die, i.e., the actual die, used in the manufacture of the stamped product, and the blank, i.e., the actual blank, used in the manufacture of the stamped product is performed.

[0203] In the forming accuracy improvement step S23 of the present embodiment, in order to reduce the influence caused by the shape change of the blank, the actual blank used in the stamping is corrected. Therefore, the forming accuracy improvement step S23 of the present embodiment includes a step S23A of determining the part requiring countermeasures of the unfolded blank model and a step S23B of assigning blank ribs.

[0204] [Steps for determining the parts that require countermeasures in the expanded blank model]

[0205] The developed blank model required countermeasure portion specifying step S23A is a step of specifying a portion on the blank model corresponding to the required countermeasure portion in the shape of the stamped product.

[0206] In this example, after determining the location requiring countermeasures in the stamped product shape obtained by stamping analysis, the stamped product shape is subjected to inverse forming analysis and expanded into a blank model. Thus, it is possible to calculate which location on the blank model the location requiring countermeasures in the stamped product shape corresponds to.

[0207] In this example, the locations where the deviation amount exceeding the threshold value occurred in the waveform blank press-formed product shape 9 are the locations A and E (see Fig.37 ). In addition, the locations where the deviation amount exceeding the threshold value is generated in the periodically offset waveform blank stamping product shape 13 are the locations A, B, and D (refer to Fig.40 ).

[0208] Therefore, in the aforementioned countermeasure-requiring portion identification step S11, the portions A, B, D, and E are identified as countermeasure-requiring portions in the shape of the stamped product.

[0209] In the step S23A of determining the locations requiring countermeasures of the developed blank model, first, the determined locations requiring countermeasures are set on a single stamped product shape. The locations requiring countermeasures in this example are locations A, B, D, and E.

[0210] The stamped product shape for the portion requiring countermeasures may be any one of the above-mentioned reference stamped product shape 5 , the waveform-shaped blank stamped product shape 9 , and the periodically offset waveform-shaped blank stamped product shape 13 .

[0211] Next, the shape of the stamped product with the required countermeasures set is subjected to reverse forming analysis and developed into a blank model. By developing the shape of the stamped product with the required countermeasures set into a blank model, the required countermeasures on the blank model can be determined.

[0212] By determining the location on the blank model where countermeasures are needed, countermeasures for reducing the influence of the shape change of the blank can be implemented on the blank before stamping. As a countermeasure, in this embodiment, ribs are given to the location of the actual blank corresponding to the location on the blank model where countermeasures are needed. Therefore, the effect of stamping using the actual blank with ribs is confirmed by stamping analysis, which is described below.

[0213] An example of providing ribs to a blank is shown in Fig.42In this embodiment, the parts requiring countermeasures (parts A, B, D, E) are set in the reference stamping product shape 5. Then, the reference stamping product shape 5 is unfolded to determine the parts requiring countermeasures on the flat blank model 3. Then, the parts requiring countermeasures on the flat blank model 3 are assigned Fig.42 tendons shown.

[0214] It should be noted that in Fig.42 The figure also shows the parts corresponding to the parts A to E of the reference stamped product shape 5 and the magnitude of the deviation generated at each part (with Fig.41 same).

[0215] like Fig.42 As shown, the parts on the blank model corresponding to the parts A, B, D, and E of the stamped product shape that require countermeasures are set as the parts that require countermeasures in the blank model. Then, ribs 15 are given to the parts A, B, D, and E in the blank model. Fig.42 The example is an example in which the rib 15 is provided in a direction intersecting or parallel to the end side of the blank model in the length direction. However, the rib of the present invention is not limited to this, and for example, the rib may be provided in a direction along the advancing direction of the corrugated shape of the corrugated blank model (the direction of the pitch of the concave and convex).

[0216] In this example, the ribs 15 are also provided to the corrugated blank model 7 and the periodically offset corrugated blank model 11. Then, using each blank model provided with the ribs 15, the same analysis as from the reference stamped product shape acquisition step S1 to the second deviation amount acquisition step S9 is performed.

[0217] It should be noted that the change and deviation in the following description are obtained by Figure 34 to Figure 41 The method shown is the same as that used to calculate .

[0218] Will Fig.42 The reference stamped product shape 21 with ribs 15 obtained by performing stamping analysis on the flat blank model 3 with ribs 15 shown in FIG. Fig.43 .

[0219] like Fig.43 As shown, the change amount of the left end portion (part A) of the reference stamping product shape 21 with ribs is 0.88mm. In addition, the left end (part B) of the top plate is -0.81mm, the longitudinal center (part C) is 6.66mm, the right end (part D) of the lower flange is 0.52mm, and the right end (part E) is -1.71mm.

[0220] Next, Fig.35 The wave-shaped blank model 7 is endowed with Fig.42The same rib 15 is shown in FIG. 1. Furthermore, the rib-bearing rib-bearing blank stamping product shape 23 obtained by performing stamping analysis on the rib-bearing blank model 7 having the rib 15 is shown in FIG. Fig.44 .

[0221] like Fig.44 As shown, the change amount of the left end portion (part A) of the wave-shaped blank stamping product shape 23 with ribs is 0.95mm. In addition, the left end (part B) of the top plate is -0.83mm, the central part in the longitudinal direction (part C) is 6.67mm, the right end (part D) of the lower flange is 0.62mm, and the right end (part E) is -1.74mm.

[0222] In addition, similarly to the first deviation amount acquisition step S5, the reference stamped product shape 21 ( Fig.43 ) and the shape of the blank stamped product with a rib-shaped waveform 23 ( Fig.44 ) and the deviation is shown in Fig.45 .

[0223] like Fig.45 As shown, the deviation between the wave-shaped blank stamping product shape 23 with ribs and the reference stamping product shape 21 with ribs is as follows: 0.07 mm at part A, -0.02 mm at part B, 0.01 mm at part C, 0.10 mm at part D, and -0.03 mm at part E.

[0224] As described above, the deviation amount when the rib 15 is provided to the blank model is different from the deviation amount when the rib 15 is not provided (refer to Fig.37 ) is significantly reduced compared to the stamped product. Therefore, it can be seen that the ribs 15 given to the blank model reduce the influence of the shape change of the blank on the dimensional accuracy of the stamped product.

[0225] Next, Fig.38 The periodic offset waveform shape blank model 11 is given with Fig.42 The same rib 15 is shown in FIG. 1. Furthermore, the periodically offset waveform shaped blank stamped product shape 25 obtained by performing stamping analysis on the periodically offset waveform shaped blank model 11 having the rib 45 is shown in FIG. Fig.46 .

[0226] like Fig.46 As shown, the change amount of the left end portion (part A) of the blank stamping product shape 25 with periodic offset waveform shape given to the rib is 0.94mm. In addition, the left end (part B) of the top plate portion is -0.82mm, the central portion in the longitudinal direction (part C) is 6.69mm, the right end (part D) of the lower flange portion is 0.56mm, and the right end (part E) is -1.73mm.

[0227] In addition, similarly to the second deviation amount acquisition step S9, the reference stamped product shape 21 ( Fig.43 ) and the periodic offset waveform shape of the blank stamped product with the ribs 25 ( Fig.16 ) and the deviation is shown in Fig.47 .

[0228] like Fig.47 As shown, the deviation of the periodically offset waveform-shaped blank stamped product shape 25 with ribs and the reference stamped product shape 21 with ribs is as follows. That is, it is 0.06mm at part A, -0.01mm at part B, 0.03mm at part C, 0.04mm at part D, and -0.02mm at part E.

[0229] In the case of a periodically offset waveform-shaped blank model, the deviation amount when the rib 15 is provided to the blank model is different from the deviation amount when the rib 15 is not provided (refer to Fig.40 ) is also significantly reduced compared to the stamped product. Therefore, it can be seen that the influence of the shape change of the blank on the dimensional accuracy of the stamped product is reduced.

[0230] The deviation amount (see Fig.45 ) and the deviation amount obtained in the second deviation amount acquisition step S9 (refer to Fig.47 ) are shown in correspondence with the target shape. Fig.48 .

[0231] like Fig.48 As shown in FIG. 1 , the deviation amount when the rib 15 is given to the blank model is as follows. That is, it is 0.06 to 0.07 mm at part A, -0.02 to -0.01 mm at part B, 0.01 to 0.03 mm at part C, 0.04 to 0.10 mm at part D, and -0.03 to -0.02 mm at part E. Fig.41 The deviation amount before the countermeasure shown is significantly smaller than that before the countermeasure.

[0232] As a result of the above analysis, the ribs 15 are provided to the locations requiring measures on the blank model determined in the step S23A of determining the locations requiring measures on the developed blank model. This can reduce the influence of the shape variation of the blank and improve the dimensional accuracy of the stamped product.

[0233] [Blank rib giving step]

[0234] The blank rib imparting step S23B is a step of imparting the rib 15 to a portion of the actual blank corresponding to the portion requiring measures determined in the developed blank model requiring measures determining step S23A.

[0235] First, the actual blank and the required countermeasures part determined in the step S23A of determining the required countermeasures part of the developed blank model are compared. Fig.42 The corresponding parts of parts A, B, D, E) are set as the parts requiring countermeasures on the actual blank.

[0236] Next, the required countermeasures are assigned to the actual blank. Fig.42 The same applies to the preforming of the ribs 15 .

[0237] It should be noted that when the ribs are given to the actual blank, Fig.42 It is appropriate to provide ribs like the ribs 15 at the parts B, D, and E of the parts. That is, it is appropriate to provide ribs in such a way that the longitudinal direction intersects with the end edge closest to the part requiring countermeasures in the actual blank. However, when it is not possible to provide ribs at the end edge closest to the part requiring countermeasures due to reasons such as the design of the component, ribs may be provided near the part requiring countermeasures, for example, near the part requiring countermeasures.

[0238] In addition, in the case of stamping an actual blank having a shape change such as continuous concavo-convex, it can also be described as follows. That is, the rib 15 can also be given to the actual blank in such a way that the length direction is along the direction of the continuous concavo-convex of the shape change of the actual blank at the position where the actual blank needs countermeasures or the position near it. Here, it is preferred to give it in such a way that the length direction is along the direction of the continuous concavo-convex of the shape change of the actual blank at the position where the actual blank needs countermeasures. However, in the case where it is impossible to give it to the position where countermeasures are needed due to reasons such as the design of the component, for example, it can also be given in such a way that the length direction is along the direction of the continuous concavo-convex of the shape change of the actual blank at the position near the position where countermeasures are needed.

[0239] By providing such ribs 15, the rigidity of the blank end during stamping is improved. In this case, the wave shape (shape change) from the blank remaining before stamping to the stamped product can be suppressed, thereby improving the dimensional accuracy of the stamped product.

[0240] It should be noted that the ribs can be convex or concave, and the length, width and height of the ribs should be appropriately determined based on the allowable height and spacing of the wavy shape (shape variation) remaining in the stamped product and the allowable degree of shape required for the target stamped product.

[0241] In addition, as the shape of the rib, a circle, an ellipse, an oval, a square, a rectangle, a triangle, a rhombus, etc. can be applied in a plan view, and a mountain shape, a trapezoid, a semicircle, a semi-ellipse, etc. can be applied in a side view.

[0242] <Steps for stamping the actual blank with ribs>

[0243] The rib-imparting actual blank press forming step S25 is a step of press forming the actual blank with the rib 15 provided at the portion corresponding to the portion requiring measures determined in the developed blank model portion requiring measures determination step S23A. The rib-imparting actual blank press forming step S25 corresponds to the forming step.

[0244] That is, the actual blank provided with the ribs 15 is press-formed using an actual die of the same type as the predetermined die model in the above-mentioned press-forming analysis.

[0245] If the actual blank with shape variation is subjected to stamping after the ribs 15 are provided, the shape of the stamped product after stamping is as follows: Fig.48 As the analysis result of the blank model, the influence of the shape change of the blank can be reduced. Therefore, a stamped product with the same good dimensional accuracy as the stamped product shape obtained by stamping analysis of the flat blank model can be obtained.

[0246] In addition, if you do not want the ribs to remain after stamping, you can also flatten them by crushing them in the coining process. In this way, strain is applied to the part with the ribs and its surroundings to perform work hardening. Therefore, the rigidity is further improved, and the wave shape of the stamped product can be suppressed from the blank before stamping, thereby improving the dimensional accuracy.

[0247] As described above, according to the present embodiment, it is possible to identify the portion greatly affected by the shape variation of the blank and take appropriate measures for the actual blank before press forming. Therefore, it is possible to stably obtain a press-formed product with good dimensional accuracy.

[0248] In this embodiment, a plurality of patterns are generated for a blank model assuming a blank with shape variation, and the deviation amount in each case is calculated to determine the location requiring countermeasures. Therefore, the difference in shape variation occurring between actual blanks is taken into consideration.

[0249] It should be noted that, although only one periodic offset waveform blank model is generated, multiple periodic offset waveform blank models can also be generated. In this case, the waveform of the periodic offset waveform blank model is preferably such that the periods are offset from each other. That is, the wavelength and amplitude are preferably common in the waveform blank model and all periodic offset waveform blank models.

[0250] By increasing the number of patterns of blank models that assume a blank with shape fluctuations, it is possible to cope with actual shape fluctuations of the blank with high accuracy.

[0251] In addition, in the above description, the shape of the stamped product when the blank is flat is compared with the shape of the stamped product when the blank has a concave and convex shape. When making this comparison, the difference in the amount of change (springback amount) from the lower dead point of the stamping direction is set as the deviation amount, but the present invention is not limited to this.

[0252] For example, the difference obtained by subtracting the height of each part of the stamped product shape after demolding when the blank is flat from the height of each part of the stamped product shape after demolding in the stamping direction when the blank has projections and depressions may be used as the deviation amount.

[0253] However, in this case, it is necessary to set a common fixed point for the two press-formed product shapes, and the amount of deviation may vary depending on the method of selecting the fixed point.

[0254] In this regard, it is preferable to compare the amounts of change based on the shape at the bottom dead point of forming, which is constant regardless of the shape of the blank, as in the present embodiment, because the amount of deviation can be accurately and easily determined.

[0255] This embodiment is performed by collision forming as an example, but even if the above embodiment is performed by deep drawing, it is possible to obtain good dimensional accuracy similar to collision forming.

[0256] The forming accuracy improvement step S23 may further include the rib providing step S13A of the first embodiment. Also, at least one of the blank rib providing step S23B and the rib providing step S13A may be selected and executed based on predetermined conditions such as target accuracy.

[0257] The present disclosure may also take the following structures.

[0258] (1) A method for manufacturing a stamped product by stamping a blank using a stamping die, the blank being obtained from a metal plate having a shape variation, comprising: A reference stamping product shape acquisition step, using a flat blank model with a flat shape, performs stamping analysis by using a predetermined die model to acquire the shape of the stamping product after demolding as the reference stamping product shape, wherein the predetermined die model is set based on the shape of the target stamping product; A step of obtaining a shape of a corrugated blank stamped product, generating a corrugated blank model having a corrugated shape with a set wavelength and amplitude based on the shape change, performing a stamping analysis of stamping using the set prescribed mold model, and obtaining a shape of the stamped product after demolding as a shape of the corrugated blank stamped product; A first deviation amount acquisition step, comparing the reference stamped product shape with the waveform-shaped blank stamped product shape, and obtaining a position where the two shapes deviate and a first deviation amount as a deviation amount of the two shapes; A step of obtaining the shape of a periodically offset waveform-shaped blank stamped product, generating one or more periodically offset waveform-shaped blank models, using the generated periodically offset waveform-shaped blank models to perform stamping analysis using the set prescribed mold model, and obtaining the shape of the stamped product after demolding as the shape of the periodically offset waveform-shaped blank stamped product, wherein the periodically offset waveform-shaped blank model has a waveform shape with an amplitude that is the same as that of a waveform shape in the waveform-shaped blank model and a period that is offset; A second deviation amount acquisition step, comparing the reference stamped product shape with one or more of the periodically offset waveform shaped blank stamped product shapes, and obtaining a position where the two shapes deviate and a second deviation amount as a deviation amount of the two shapes; a step of determining a portion requiring countermeasures, determining a portion of the stamped product that is equivalent to a portion where a deviation of the first deviation amount exceeding a preset threshold value has occurred and a portion where a deviation of the second deviation amount exceeding a preset threshold value has occurred as a portion requiring countermeasures; and The forming accuracy improvement step corrects the shape of at least one of the forming surface of the actual mold and the actual blank so that the deviation at the location requiring measures determined in the step of determining the location requiring measures becomes smaller. The actual mold is the stamping mold used in the manufacture of the stamped product, and the actual blank is the blank used in the manufacture of the stamped product.

[0259] (2) In the first deviation amount obtaining step, The difference between the springback amount of a predetermined portion in the reference stamped product shape and the springback amount of a portion in the waveform-shaped blank stamped product shape that is the same as the predetermined portion in the reference stamped product shape is obtained as the first deviation amount. In the second deviation amount obtaining step, The difference between the springback amount at a predetermined portion of the reference stamped product shape and the springback amount at the same portion as the predetermined portion of the reference stamped product shape in the periodically offset waveform blank stamped product shape is obtained as the second deviation amount.

[0260] (3) The step of improving the molding accuracy includes a step of providing ribs to a portion of the molding surface of the actual mold where the portion requiring measures is formed, or to a portion where the portion requiring measures and its surroundings are formed.

[0261] (4) The rib providing step provides ribs to the actual die so that a longitudinal direction of a rib mark formed on the press-formed product by the ribs provided to the actual die intersects with an end side of the press-formed product that is closest to the portion requiring countermeasures.

[0262] (5) The actual blank has a shape with continuous concavity and convexity along a prescribed direction, The rib imparting step imparts ribs to the actual die in such a manner that the length direction of the rib marks formed on the stamped product by the ribs imparted to the actual die is along the direction in which the concavities and convexities of the shape variation of the blank at the portion of the stamped product requiring countermeasures are continuous.

[0263] (6) comprising a real stamping step of stamping the blank using a real die provided with the ribs, In the actual stamping step, a rib mark is formed at a portion of the stamped product that requires countermeasures, or at a portion including the portion that requires countermeasures and its surroundings. The method further includes a coining step of punching the stamped product punched in the actual stamping step again to crush the rib marks.

[0264] (7) The step of improving forming accuracy comprises: The step of determining the part requiring countermeasures of the unfolded blank model, setting the part requiring countermeasures in any one of the reference stamped product shape, the waveform-shaped blank stamped product shape and the periodically offset waveform-shaped blank stamped product shape and unfolding it into a blank model, and determining the part requiring countermeasures on the unfolded blank model; and The step of providing a rib to a portion of the actual blank corresponding to the portion requiring measures determined in the step of determining the portion requiring measures of the developed blank model.

[0265] (8) The step of providing the rib to the actual blank includes providing the rib to the actual blank so that the longitudinal direction of the rib intersects with the end side of the actual blank closest to the portion requiring measures.

[0266] (9) The actual blank has a shape in which the concavity and convexity continuously change along a predetermined direction, The step of providing the blank ribs provides the actual blank with ribs such that the length direction of the ribs provided to the blank is along a direction in which the concavities and convexities of the shape variation of the actual blank at the portion requiring countermeasures of the actual blank continue.

[0267] (10 includes a forming step, wherein the forming step uses the actual mold to stamp the actual blank with the ribs, After the forming step, there is a step of performing press forming to crush the rib.

[0268] The entire contents of Japanese Patent Application No. 2022-117070 (filed on July 22, 2022) and Japanese Patent Application No. 2022-198304 (filed on December 13, 2022) to which this application claims priority are hereby incorporated by reference into this disclosure. Although the invention has been described with reference to a limited number of embodiments, the scope of the invention is not limited thereto, and modifications based on the embodiments disclosed above will be apparent to those skilled in the art.

[0269] Description of symbols 1 Stamped product (target shape) 3 Flat blank model 5 Standard stamping product shapes 7 Wave-Shaped Blank Model 9 Shape of stamped product from corrugated blank 11 Periodic offset waveform shape blank model 13 Periodic deviation waveform shape Blank stamping product shape 15 tendons 21 Standard stamping product shapes 22 Muscle Marks 23 Shape of stamped product from corrugated blank 25 Periodic offset waveform shape Blank stamping product shape 31 Standard stamping product shape 33 Shape of stamped product from corrugated blank 41 Periodic offset waveform shape blank model 43 Periodically offset wave-shaped blank stamping product shape 51 Standard stamping product shapes 53 Shape of stamped product from corrugated blank 55 Periodically offset waveform shape of blank stamped product.

Claims

1. A method for manufacturing a stamped product, comprising: stamping a blank using a stamping die to stamp the blank, the blank being obtained from a metal plate having a shape change, wherein: include: A reference stamping product shape acquisition step, using a flat blank model with a flat shape, performs stamping analysis by using a predetermined die model to acquire the shape of the stamping product after demolding as the reference stamping product shape, wherein the predetermined die model is set based on the shape of the target stamping product; A step of obtaining a shape of a corrugated blank stamped product, generating a corrugated blank model having a corrugated shape with a set wavelength and amplitude based on the shape change, performing a stamping analysis of stamping using the set prescribed mold model, and obtaining a shape of the stamped product after demolding as a shape of the corrugated blank stamped product; A first deviation amount acquisition step, comparing the reference stamped product shape with the waveform-shaped blank stamped product shape, and obtaining a position where the two shapes deviate and a first deviation amount as a deviation amount of the two shapes; A step of obtaining the shape of a periodically offset waveform-shaped blank stamped product, generating one or more periodically offset waveform-shaped blank models, using the generated periodically offset waveform-shaped blank models to perform stamping analysis using the set prescribed mold model, and obtaining the shape of the stamped product after demolding as the shape of the periodically offset waveform-shaped blank stamped product, wherein the periodically offset waveform-shaped blank model has a waveform shape with an amplitude that is the same as that of a waveform shape in the waveform-shaped blank model and a period that is offset; A second deviation amount acquisition step, comparing the reference stamped product shape with one or more of the periodically offset waveform shaped blank stamped product shapes, and obtaining a position where the two shapes deviate and a second deviation amount as a deviation amount of the two shapes; a step of determining a portion requiring countermeasures, determining a portion of the stamped product that is equivalent to a portion where a deviation of the first deviation amount exceeding a preset threshold value has occurred and a portion where a deviation of the second deviation amount exceeding a preset threshold value has occurred as a portion requiring countermeasures; and The forming accuracy improvement step corrects the shape of at least one of the forming surface of the actual mold and the actual blank so that the deviation at the location requiring measures determined in the step of determining the location requiring measures becomes smaller. The actual mold is the stamping mold used in the manufacture of the stamped product, and the actual blank is the blank used in the manufacture of the stamped product.

2. The method for manufacturing a press-formed product according to claim 1, wherein: The first deviation amount acquisition step acquires the difference between the springback amount of a specified portion in the reference stamped product shape and the springback amount of a portion in the waveform-shaped blank stamped product shape that is the same as the specified portion of the reference stamped product shape as the first deviation amount, The second deviation amount acquisition step acquires the difference between the springback amount of a specified portion in the reference stamped product shape and the springback amount of a portion in the periodically offset waveform shaped blank stamped product shape that is the same as the specified portion of the reference stamped product shape as the second deviation amount.

3. The method for manufacturing a press-formed product according to claim 1 or 2, wherein: The step of improving the molding accuracy includes a step of providing ribs to a portion of the molding surface of the actual mold where the portion requiring measures is formed, or to a portion where the portion requiring measures and its surroundings are formed.

4. The method for manufacturing a stamped product according to claim 3, wherein: The rib imparting step imparts ribs to the actual die in such a manner that the length direction of rib marks formed on the stamped product by the ribs imparted to the actual die becomes a direction intersecting with the end edge of the stamped product that is closest to the portion requiring countermeasures.

5. The method for manufacturing a stamped product according to claim 3, wherein: The actual blank has a shape variation in which the concavity and convexity continuously change along a predetermined direction. The rib imparting step imparts ribs to the actual die in such a manner that the length direction of the rib marks formed on the stamped product by the ribs imparted to the actual die is along the direction in which the concavities and convexities of the shape variation of the blank at the portion of the stamped product requiring countermeasures are continuous.

6. The method for manufacturing a press-formed product according to any one of claims 3 to 5, wherein: The method for manufacturing a stamped product includes an actual stamping step of stamping the blank using an actual die provided with the ribs. In the actual stamping step, a rib mark is formed at a portion of the stamped product that requires countermeasures, or at a portion including the portion that requires countermeasures and its surroundings. The method for manufacturing the stamped product further includes a coining step of re-punching the stamped product stamped in the actual stamping step to crush the rib marks.

7. The method for producing a press-formed product according to any one of claims 1 to 6, wherein: The forming accuracy improvement step comprises: The step of determining the part requiring countermeasures of the unfolded blank model, setting the part requiring countermeasures in any one of the reference stamped product shape, the waveform-shaped blank stamped product shape and the periodically offset waveform-shaped blank stamped product shape and unfolding it into a blank model, and determining the part requiring countermeasures on the unfolded blank model; and The step of providing a rib to a portion of the actual blank corresponding to the portion requiring measures determined in the step of determining the portion requiring measures of the developed blank model.

8. The method for manufacturing a press-formed product according to claim 7, wherein: The step of providing the blank rib provides the actual blank with a rib so that a longitudinal direction of the rib becomes a direction intersecting an end side of the actual blank closest to the portion requiring measures.

9. The method for manufacturing a press-formed product according to claim 8, wherein: The actual blank has a shape variation in which the concavity and convexity continuously change along a predetermined direction. The step of providing the blank ribs provides the actual blank with ribs such that the length direction of the ribs provided to the blank is along a direction in which the concavities and convexities of the shape variation of the actual blank at the portion requiring countermeasures of the actual blank continue.

10. The method for manufacturing a press-formed product according to any one of claims 7 to 9, wherein: The method for manufacturing a stamped product includes a forming step of stamping a real blank provided with the ribs using the real die, After the forming step, there is a step of performing press forming to crush the rib.

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