Method for evaluating molding inflow rate, manufacturing method of pressed part, device for evaluating molding inflow rate, and device for manufacturing pressed part

Abstract

To provide a technique that can evaluate inflow of a material using means with versatility, without being influenced by vibration caused during pressing, in press-molding a work-piece such as a thin steel sheet.SOLUTION: In a method for evaluating inflow in molding, which evaluates inflow in molding which is inflow of a material caused by pressing molding, in press-molding a work-piece 1A to manufacture a pressed component, an image of the press-molded work-piece is photographed with a camera 11, an outer peripheral contour 1Aa of the press-molded work-piece is detected from data on the photographed image, an evaluation-determination amount for evaluating the inflow in molding is calculated on the basis of the data on the photographed image and the detected outer peripheral contour 1Aa, and the inflow in molding is evaluated on the basis of the calculated evaluation-determination amount.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a technology for evaluating the amount of material flowing in when a workpiece such as a thin steel plate is press-formed. The present invention is also applicable to, for example, detecting defects in advance from changes in the amount of material flowing in during mass production of pressed parts. [Background technology]

[0002] In mass production presses for manufacturing mass-produced products such as automobile parts, variations in material properties of thin steel sheets and changes in press forming conditions, including mold damage, occur. These can cause forming defects such as cracks and wrinkles, which in turn reduces productivity. Draw forming, in which material is sandwiched between a die and a blank holder and pressed against a punch, is a forming method that is widely used in press forming of automotive parts. However, draw forming is also a forming method in which press forming conditions are easily changed.

[0003] For example, if the roughness of the die's forming surface changes, the sliding conditions between the material and the die change, which in turn changes the amount of material that flows in. Also, the draw bead controls the amount of material that flows in, but poor draw bead management can change the amount of material that flows in. Furthermore, the distance block height adjusts the gap between the die and blank holder, but the amount of material that flows in can also change depending on the distance block height setting.

[0004] Furthermore, in mass production presses, continuous press forming accumulates frictional heat in the mold. This accumulated frictional heat causes the mold to expand in volume, changing the gap between the die and the blank holder, which also changes the inflow rate. The inflow rate also changes if foreign matter such as plastic is attached to the workpiece.

[0005] As mentioned above, in draw forming, the amount of material flowing in is easily affected by changes in forming conditions. If the amount of material flowing in is less than the appropriate amount, strain will concentrate in other areas, making the part more likely to crack. Conversely, if the amount of material flowing in is more than the appropriate amount, excess material will be left over, making the part more likely to wrinkle. Therefore, in mass production presses, it is necessary to constantly monitor whether the inflow rate of molded parts is appropriate, and by understanding the trend of changes, it is possible to predict the occurrence of defects in advance.

[0006] Techniques for addressing this issue include those described in Patent Documents 1 to 5, for example. In Patent Document 1, a wire rope is attached to the end of the workpiece to be pressed, and a camera captures the amount of material that is drawn in as the material flows in. In this way, Patent Document 1 proposes a method for measuring the amount of material that flows in.

[0007] In Patent Document 2, an air cylinder with a linear sensor is connected to the end of the workpiece to be pressed. Patent Document 2 also proposes a method for measuring the inflow amount by calculating the amount of air drawn in as the end of the workpiece flows in. Patent Document 3 proposes a method for measuring the amount of inflow by measuring the amount of work drawn in by the inflow of the work to be pressed using a non-contact laser displacement meter.

[0008] In addition, in Patent Document 4, a camera embedded in a mold is used to analyze images of the flattened portion of the steel plate surface before and after the workpiece is moved to be pressed, thereby proposing a method for measuring the inflow amount, pressing force, and strain amount. In Patent Document 5, the temperature of a molded part is measured using a radiation thermometer such as a thermograph after press molding. Patent Document 5 also proposes a method of recognizing the difference between the molded part temperature and the outside air temperature as a boundary and calculating the change in inflow rate from the number of pixels at the changed boundary. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 4766251 [Patent Document 2] Patent No. 4816922 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-34716 [Patent Document 4] Japanese Patent Application Laid-Open No. 2012-11453 [Patent Document 5] Japanese Patent Application Laid-Open No. 2012-50998 Summary of the Invention [Problem to be solved by the invention]

[0010] The methods proposed in Patent Documents 1 to 3 can only measure the inflow amount at a specific position on a molded part. Therefore, it is necessary to identify the measurement position for each part, which affects the occurrence of molding defects such as cracks and wrinkles. In addition, the position where the inflow amount is measured varies for each part. Therefore, the positions of markers, cameras, air cylinders with linear sensors, and laser displacement meters must be incorporated into the design for each mold. Therefore, the methods proposed in Patent Documents 1 to 3 lack versatility. Furthermore, with the methods proposed in Patent Documents 1 to 3, if the edge of the molded part is bent, the measurements of the various measuring devices cannot follow the inflow. Furthermore, with the methods proposed in Patent Documents 1 to 3, if there is vibration due to impact during pressing, the vibration may prevent accurate measurements.

[0011] The method proposed in Patent Document 4, like the above, can only measure the inflow amount at a specific position, and the camera installation position must be incorporated into the design for each mold, which makes it less versatile. The method proposed in Patent Document 5 does not require the camera installation position to be designed for each mold, and can measure changes in inflow over a relatively wide range. However, with the method proposed in Patent Document 5, there is a concern that the boundary between the molded part and the outside air may become unclear due to changes in the outside air temperature, resulting in measurement errors. In addition, the pixels of the temperature distribution image measured by thermography or the like are relatively large. For this reason, the method proposed in Patent Document 5 is prone to reducing the measurement resolution of the inflow.

[0012] The present invention has been made in light of the above points and relates to the evaluation of press forming of workpieces such as thin steel sheets. The present invention aims to provide a technique that can evaluate material flow using a versatile means that is not affected by vibrations during pressing. [Means for solving the problem]

[0013] In order to solve the problem, one aspect of the present invention is a method for evaluating a molding inflow amount, which is the amount of material that flows in through press molding when a workpiece is press-molded to produce a press part.The method for evaluating a molding inflow amount comprises: imaging the workpiece after press molding from the thickness direction of the workpiece; detecting the outer peripheral contour of the workpiece after press molding from the image data; calculating an evaluation judgment amount for evaluating the molding inflow amount based on the image data and the detected outer peripheral contour; and evaluating the molding inflow amount based on the calculated evaluation judgment amount. [Effects of the Invention]

[0014] According to this aspect of the present invention, the amount of material flowing in during press molding is evaluated based on a feature quantity (evaluation determination quantity) defined by the contour of the molded part detected from an image of the molded part after press molding captured by an imaging device. Therefore, it is possible to evaluate the amount of material flowing in the entire molded part without being affected by vibrations during press molding. Furthermore, the information required for this evaluation can be obtained during any process, such as during an idle process after press molding or on a conveying device, which eliminates the need to design a camera installation position for each mold, enabling general-purpose evaluation of the inflow amount.

[0015] Furthermore, since the boundaries of molded parts are recognized directly from captured images through image analysis, it is less susceptible to disturbances such as outside temperature. Also, since it is possible to capture images with a high pixel count, it is possible to measure the inflow rate with a relatively high resolution. Furthermore, by using the evaluation method according to the embodiment of the present invention, it is possible to detect the occurrence of defects in advance from changes in the inflow rate during mass production. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram illustrating an example of a manufacturing device for a pressed part. [Figure 2] FIG. 1 is a diagram illustrating an example of a manufacturing device for a pressed part. [Figure 3] 1 is a diagram showing a configuration of an evaluation device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating an example of a mounting table. [Figure 5] FIG. 2 is a diagram illustrating a configuration of a calculation processing unit. [Figure 6] 1 is a perspective view illustrating a pressed part exemplified in an embodiment based on the present invention. FIG. [Figure 7] FIG. 2 is a plan view showing the workpiece (a) before forming and the workpiece (b) after forming. [Figure 8] FIG. 1 is a flow diagram showing an example of an evaluation method. [Figure 9] FIG. 10 is a diagram showing an evaluation in the first embodiment. [Figure 10] FIG. 1 is a diagram illustrating press molding. [Figure 11] FIG. 2 is a plan view showing a workpiece in the embodiment; [Figure 12] FIG. 10 is a plan view illustrating the orientation of the workpiece after molding. [Figure 13] FIG. 10 is a diagram showing the relationship between BHF and contour area. [Figure 14] FIG. 10 is a diagram showing the relationship between BHF and contour perimeter. [Figure 15] FIG. 10 is a diagram showing the relationship between lubrication conditions and contour inner area. [Figure 16]FIG. 10 is a diagram showing the relationship between lubrication conditions and contour periphery length. [Figure 17] FIG. 10 is a diagram showing an evaluation in the second embodiment. [Figure 18] FIG. 10 is a diagram illustrating the relationship between BHF and similarity. [Figure 19] FIG. 10 is a diagram showing the relationship between lubrication conditions and similarity. [Figure 20] 10 is a diagram showing the relationship between a reference point H, a direction K, and a distance L in the third embodiment. FIG. [Figure 21] 10 is a diagram showing the relationship between a reference point H, a direction K, and a distance L in the third embodiment. FIG. [Figure 22] FIG. 1 is a diagram showing the relationship between direction and distance (L: length) for an angle of 360°. [Figure 23] FIG. 1 is a diagram showing the relationship between the direction and distance (L: length) over an angle of 360° under different lubrication conditions. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments based on the present invention will be described with reference to the drawings. (Pressed part manufacturing equipment) In this embodiment, as an example of a press part manufacturing apparatus, the present invention can be applied to a transfer press line in which a plurality of press processes 3A to 3D are arranged in series, as shown in Fig. 1. It can also be applied to a tandem press line as shown in Fig. 2. Of course, the present disclosure can also be applied to a press line with only one press process. In the transfer press line illustrated in Fig. 1, a workpiece 1 (blank) such as a thin steel plate is transferred by a transfer device 2 such as a robot arm and transported into a transfer press 3. In this embodiment, a case where draw forming is performed in the press forming in the first process 3A is illustrated.

[0018] In this embodiment, the press line is provided with an evaluation device for the molding inflow rate of this embodiment. In the case of the transfer press line shown in Fig. 1, for example, the second process 3B is set as an idle process in which no processing is performed. In the second process 3B (idle process), devices such as a camera 11 for evaluation and a lighting device are installed, and image data of the formed part 1A (workpiece 1 after press forming) after draw forming (after press forming) is acquired from above.

[0019] In the case of a tandem press line as shown in FIG. 2, similar to the transfer press line of FIG. 1, a workpiece 1 such as a thin steel plate is transported into a press machine 4A by a robot arm 2 or the like. Then, the workpiece 1 undergoes draw forming as press forming in the first process 4A. Thereafter, devices such as a camera 11 for evaluation and a lighting device are installed along the way as the formed part 1A is transported by a conveyor or the like to the press machine that performs the second process 4B. Then, an image of the formed part 1A after draw forming is taken. The press forming for evaluating the amount of material inflow (molding inflow) is not limited to draw forming. The amount of material inflow (molding inflow) may be evaluated after two or more press forming processes.

[0020] (Evaluation device for molding inflow amount) "First embodiment" Next, the molding inflow rate evaluation device of this embodiment will be described. In the following description, the press forming to be evaluated is performed by draw forming, and in this embodiment, the workpiece 1 after press forming is referred to as a formed part 1A. FIG. 3 is a schematic diagram illustrating the configuration of the molding inflow rate evaluation device of this embodiment. As shown in Fig. 3, the molding inflow rate evaluation device of this embodiment includes a mounting table 14, a camera 11, a control computer 15, and external devices 16 such as a monitor 16A and an alarm 16B. In Fig. 3, reference numeral 10 denotes a press machine, and reference numeral 10A denotes a control device for the press machine 10.

[0021] <Placement Table 14> The mounting table 14 is a table for taking an image, and is a table on which the molded part 1A produced by press molding is placed. An example of the mounting table 14 is shown in FIG. 4. That is, the mounting table 14 may be a flat table as shown in FIG. 4(a). Alternatively, the mounting table 14 may have a movable upper surface (mounting surface 14a) like a conveyor as shown in FIG. 4(b). Alternatively, the mounting table 14 may be configured as a jig or the like having a surface shaped to follow the shape of the molded portion of the molded part 1A so that the image of the molded part 1A is always taken in the same direction as shown in FIG. 4(c). Furthermore, the upper surface (mounting surface 14a) of the mounting table 14 is preferably painted or colored in a color such as black, white, or green, so that the background color is different from the color of the molded part 1A. This allows the boundary between the upper surface of the mounting table 14 and the molded part 1A to be clearly recognized. Furthermore, the upper surface (mounting surface 14a) of the mounting table 14 may be provided with grid-like lines or markings for the purpose of defining the position and orientation of the molded part 1A.

[0022] <Camera 11> The camera 11 is an imaging device that captures an image from above of the molded part 1A placed on the mounting table 14. The camera 11 is disposed above the imaging position on the mounting table 14, with its imaging axis pointing downward toward the imaging position. Reference numeral 13 denotes a support member that supports the camera 11.

[0023] Camera 11 is installed in a position where it can capture an image of the entire molded part 1A. Preferably, camera 11 is positioned so that it is focused on molded part 1A. For example, an imaging area that fits the entire molded part 1A is defined, and the imaging axis of camera 11 is set to face the center of that imaging area. The imaging axis of camera 11 is preferably perpendicular (vertical) to the top surface (center) of mounting table 14, but imaging may also be performed from a position where the imaging axis is tilted. If the imaging axis of camera 11 is tilted to take into account interference with other parts, it is preferable to perform image conversion using image processing so that the image data is captured from above. Furthermore, depending on the environment of the press line, an illumination device 12 may be used if necessary, as shown in Figure 3. The illumination device 12 brightens the area to be photographed. The image data (captured image) captured by the camera 11 is supplied to a control computer 15.

[0024] <Control Computer 15> As shown in FIG. 3, the control computer 15 includes an input / output unit 15A, a processing unit 15B, and a storage unit 15C including a hard disk or the like. The input / output unit 15A receives image data from the camera 11 and stores it in the storage unit 15C. 5, the calculation processing unit 15B includes a contour detection unit 15Ba, an evaluation determination amount calculation unit 15Bb, and an evaluation unit 15Bc. The contour detection unit 15Ba and the evaluation determination amount calculation unit 15Bb are processing units that perform image processing on image data by computer processing.

[0025] The evaluation results (measurement results) and image data processed by the control computer 15 are output to an external device 16 such as a monitor. This allows an operator or the like to visually check the condition of the molded part 1A. Furthermore, if an abnormality is found in the measurement results, an indicator light or the like can be used to warn those in the vicinity of the abnormality. Furthermore, the control computer 15 is connected to the control device 10A of the press machine 10. If the control computer 15 estimates an abnormality in the formed part 1A from the obtained evaluation results, it can send a control signal to the control device 10A of the press machine 10 to stop press forming, etc. The control computer 15 may also receive a signal from the control device 10A of the press machine to indicate the end of pressing.

[0026] [Contour detection unit 15Ba] The contour detection unit 15Ba executes a process of detecting the outer contour of the molded part 1A by image processing from the captured image data. Before detecting the outer periphery contour, the contour detection unit 15Ba may perform a known image conversion process on the image data in order to improve the detection accuracy of the outer periphery contour. Examples of image conversion processing include grayscale conversion, resizing, and smoothing. Grayscale conversion is performed to clarify the boundary between the molded part 1A and the background. Resizing (processing to change the size of an image) is performed to make the image size easier to process. Smoothing is performed to remove noise from the image.

[0027] [Evaluation determination amount calculation unit 15Bb] The evaluation determination quantity calculation unit 15Bb calculates an evaluation determination quantity for evaluating the molding inflow amount based on the captured image data and the outer peripheral contour detected by the contour detection unit 15Ba. The evaluation determination quantity is a feature quantity defined by the detected outer peripheral contour. Here, the inventors have made the following findings through various studies. The outline shape of the material after it has flowed in by draw forming was detected by the image analysis described above, and the area inside the outline enclosed by the outline and the perimeter of the outline, etc., were calculated as evaluation criteria. It was then found that this evaluation criteria is positively correlated with the amount of material that flows in during press forming. In other words, it was found that the feature quantity defined by the outline of the workpiece 1 after forming is positively correlated with the amount of material that flows in during press forming. Based on this finding, it was found that by calculating the evaluation criteria, it is possible to detect changes in the amount of material that flows in during mass production press forming and predict the occurrence of defects in advance.

[0028] In this embodiment, at least one of the area surrounded by the outer peripheral contour in the image data and the outer peripheral length of the molded part 1A defined by the outer peripheral contour is calculated as the evaluation determination amount. The area enclosed by the contour is calculated, for example, by the number of pixels enclosed by the contour. The contour length is also calculated, for example, by the number of pixels where the contour is located, i.e., overlaps. If the output value is in pixels, it is desirable to image an object with a known length under the same imaging conditions as when the molded part 1A was imaged, calculate the length per pixel, and then perform calibration.

[0029] [Evaluation Section 15Bc] The evaluation unit 15Bc evaluates the molding inflow amount based on the evaluation determination amount, which is the characteristic amount calculated by the evaluation determination amount calculation unit 15Bb. The evaluation unit 15Bc, for example, calculates the difference between a reference evaluation amount, which is a preset reference evaluation amount, and the evaluation determination amount calculated by the evaluation determination amount calculation unit 15Bb, and evaluates the molding inflow amount based on the difference. For example, if the calculated difference is equal to or greater than a preset threshold, the evaluation unit 15Bc determines that the molding inflow amount is abnormal. There is a positive correlation between the area enclosed by the outer contour and the outer periphery length and the amount of material inflow during press molding. In other words, the evaluation criterion amount is an index value that defines the amount of material inflow, which is proportional to the amount of material inflow. Therefore, the difference between the reference evaluation amount and the calculated evaluation criterion amount is an index value that represents the change in the amount of material inflow relative to the reference value. The reference evaluation amount may be obtained in advance by conducting an experiment or the like.

[0030] Furthermore, in the case of equipment that sequentially press-forms workpieces 1 of the same shape into the same press parts, the reference evaluation amount may be set as follows. Note that this equipment is mass production equipment that manufactures the same press parts. In this case, the reference evaluation amount for the current evaluation may be the average value of the evaluation judgment amounts obtained before the press forming to be evaluated (the evaluation judgment amounts for the first few times may also be used), or the evaluation judgment amount obtained immediately before. In this case, it is possible to evaluate changes from past press forming, and to detect molding defects in the process of sequentially manufacturing mass-produced products from changes in the amount of material inflow due to press forming.

[0031] <Processing in the arithmetic processing unit 15B> Next, the processing performed by the arithmetic processing unit 15B, that is, the method for evaluating the molding inflow rate of the press-molded part 1A, will be described in detail. Here, a method for evaluating the forming inflow amount will be described using an example in which the press-formed part 1A is a square cylindrical draw-formed part made of a thin steel plate as shown in FIG. Fig. 7(a) shows a plan view of a thin steel sheet (workpiece 1) before forming, and Fig. 7(b) shows a plan view of a rectangular tube draw-formed part 1A (workpiece 1 after press forming). In this formed part 1A, as the rectangular tube portion is formed by draw forming, a large amount of material flows into the four sides of the workpiece 1 such as a thin steel plate, as shown in FIG. 7(a)→(b).

[0032] Here, the captured image data is processed using the image processing flow shown in Fig. 8, and the boundary between the molded part 1A and the background is recognized as a contour 1Aa. Fig. 8 illustrates an example in which an index value (evaluation determination amount) of the inflow amount is measured. There are no particular limitations on the image processing method, and any known image processing method can be applied. Here, image processing was performed by implementing OpenCV, an open source computer vision library, in a Python program.

[0033] <Image resizing (step S10)> The captured image, depending on the performance of the camera 11, is composed of, for example, 4000 x 6000 pixels. If the number of pixels is too large, problems may occur in detecting the contour 1Aa. For this reason, the image size is changed to, for example, about 800 x 1200 pixels. This makes it possible to more accurately detect the contour 1Aa of the molded part 1A from the image data.

[0034] <Grayscale Conversion (Step S20)> As a preliminary step for image processing, if the image data is a color image stored in RGB format, the image data is converted to a grayscale format that represents white to black on a scale of 0 to 255.

[0035] <Smoothing (Step S30)> In addition to the target molded part 1A, the captured image may contain multiple noises due to reflected light, etc. This noise can reduce the accuracy of detecting the contour 1Aa of the molded part 1A. To prevent this, the image data is smoothed by passing it through various filters. Known filters such as an averaging filter, median filter, Laplacian filter, and Gaussian filter can be used.

[0036] <Boundary Acquisition (Step S40)> The boundary detection unit performs processing to acquire the boundary between the molded part 1A and the background in order to detect the contour 1Aa of the molded part 1A from the image. This can be done using an edge detection function such as a Sobel filter or a Canny filter, or by performing binarization processing so that the molded part 1A appears white and the background appears black. Any known processing can be used to detect the contour 1Aa.

[0037] <Contour detection (step S50)> The boundary detection unit obtains the boundary between the molded part 1A and the background, and then detects the closed outermost contour 1Aa within that boundary. If there are multiple detected contours 1Aa in the list, additional conditions, such as the area or length of the contour 1Aa, are added to perform processing so that only the contour 1Aa of the molded part 1A is detected.

[0038] <Feature Calculation (Step S60)> The evaluation determination quantity calculation unit 15Bb calculates the evaluation determination quantity, which is made up of the area and outer periphery length inside the detected contour 1Aa of the molded part 1A, as a feature quantity that serves as an index value of the molding inflow amount. Figure 9 shows an image of the measurement results after calculating the evaluation judgment quantities (feature quantities). In Figure 9, the contour 1Aa of the molded part 1A is highlighted. The area within the contour 1Aa and the perimeter length along the contour 1Aa are also displayed on the same screen as feature quantities. In addition to the above feature quantities, Figure 9 also displays a rectangle that circumscribes the contour 1Aa with the smallest area, along with its width and height. The center of gravity G of the contour 1Aa is also calculated and displayed from the image moment of the contour 1Aa.

[0039] Furthermore, although this depends on the image processing tool, if the output values ​​of the various calculated feature quantities related to length and area are in pixel units, it is preferable to process them as follows: That is, it is preferable to image an object whose length is known in advance under the same imaging conditions as when the molded part 1A was imaged, find the length per pixel, and then perform calibration.

[0040] (Operation etc.) In this embodiment, the press forming of a workpiece 1 such as a thin steel plate is evaluated. That is, in this embodiment, an evaluation criterion for evaluating the amount of material inflow is obtained from image data of a formed part 1A after press forming captured by a camera 11. The amount of material inflow is then evaluated from the obtained evaluation criterion. Therefore, it is possible to stably evaluate the amount of material inflow for the entire formed part 1A without being affected by vibrations during press forming. In this embodiment, the evaluation determination quantity is a feature quantity defined by the detected contour 1Aa of the molded part 1A. As will be described later, the feature quantity defined by the contour 1Aa of the molded part 1A has a positive correlation with the amount of material inflow. Therefore, the amount of material inflow can be evaluated using the evaluation determination quantity.

[0041] In the above description, the area within the contour defined by the contour 1Aa and the perimeter length are exemplified as evaluation and determination quantities. The area has a higher correlation with the amount of material flowing in than the perimeter length (see Examples). For this reason, the area is more preferable to the perimeter length as an evaluation and determination quantity. Furthermore, in this embodiment, the information for evaluation can be acquired at any process, such as an idle process after press molding or during transportation, etc. Therefore, there is no need to design the installation position of the camera 11 for each mold, and the inflow amount can be evaluated in a general manner.

[0042] Furthermore, in this embodiment, the boundaries of the molded part 1A are recognized directly from the captured image through image analysis. Therefore, the acquisition of information for evaluation is less susceptible to disturbances such as outside temperature. In addition, the ability to capture images with a high pixel count allows for measurement of the inflow rate with relatively high resolution. Furthermore, by applying the method of the present disclosure, it is possible to detect defects in advance from changes in the inflow rate during mass production.

[0043] "Second embodiment" Next, a molding inflow rate evaluation device and evaluation method according to a second embodiment will be described with reference to the drawings. The basic configuration of the second embodiment is the same as that of the first embodiment, so a description of the same processing as in the first embodiment will be omitted. The second embodiment differs from the first embodiment in that the shape of the outer peripheral contour 1Aa is used as the evaluation determination amount. Therefore, the processing of the evaluation determination amount calculation unit 15Bb and the evaluation unit 15Bc in the second embodiment will be described below.

[0044] [Evaluation determination amount calculation unit 15Bb] The evaluation determination quantity calculation unit 15Bb calculates the contour shape of the molded part 1A defined by the detected outer peripheral contour 1Aa as an evaluation determination quantity (feature quantity).

[0045] [Evaluation Section 15Bc] The evaluation unit 15Bc calculates the degree of similarity between the set reference contour shape (reference evaluation amount) and the contour shape that is the evaluation determination amount. The evaluation unit 15Bc then evaluates the molding inflow rate based on the calculated similarity. For example, it determines whether the calculated similarity is within a set range (similar), and if it is within the range, it determines that there is no abnormality in the molding inflow rate. The reference contour shape may be obtained in advance by conducting an experiment or the like.

[0046] Furthermore, in the case of equipment that sequentially press-forms workpieces 1 of the same shape into the same press part, the reference contour shape may be set as follows. Note that this equipment is a mass production equipment that produces the same press part. In this case, the reference contour shape to be used this time may be the average value of the evaluation judgment amount obtained before the press forming to be evaluated (the evaluation judgment amount for the first few times may be used), or the evaluation judgment amount obtained immediately before. In this case, it is possible to evaluate changes from past press forming, and it becomes possible to detect forming defects in the process of sequentially manufacturing mass-produced products from changes in the amount of material inflow due to press forming.

[0047] <About similarity> In this embodiment, the contour shape of the workpiece 1 after flowing in by press molding is detected by image analysis. Then, a predetermined reference contour shape is compared with the contour shape (feature value) of the molded part 1A to be evaluated, and the similarity is calculated. The inventors have found that the calculated similarity can be used to evaluate changes in the flow rate during mass production press molding, and to predict the occurrence of defects in advance. In this embodiment, the reference contour shape is compared with the contour shape of the molded part 1A to be evaluated, and the similarity is calculated. This similarity serves as an index value for the molding inflow rate of the reference molded part 1A corresponding to the reference contour shape. An image of the measurement results after calculating the feature amount (contour shape) is shown in Fig. 17. In Fig. 17, the reference contour shape 40 and the contour shape of the part to be measured are displayed on the same screen. In addition, Fig. 18 displays the calculated similarity between both contour shapes.

[0048] [Example of similarity calculation method] The similarity can be calculated using any known method. Similarity can be calculated using, for example, the matchShapes function implemented in OpenCV, an open-source computer vision library. The matchShapes function has three modes for calculating the similarity between two contour shapes. The similarities I1(A,B), I2(A,B), and I3(A,B) for each mode are expressed by the following formulas:

[0049]

number

[0050] Here, A and B respectively represent the reference molded part corresponding to the reference contour shape and the molded part 1A to be evaluated. A and mi B is calculated by the following formula:

[0051]

number

[0052] Here, hi A and hi B indicate the outer peripheral contour of the reference molded part and the Hu moment of the molded part 1A to be measured, respectively. If the degree of similarity does not meet a preset standard, for example, it is determined that there was an abnormality in the press molding of the molded part 1A to be evaluated. Other than that, the same processing as in the first embodiment may be executed.

[0053] "Third embodiment" Next, a molding inflow rate evaluation device and evaluation method according to a third embodiment will be described with reference to the drawings. The basic configuration of the third embodiment is the same as that of the first embodiment, so a description of the same processing as in the first embodiment will be omitted. The third embodiment differs from the first embodiment in that the shape of the outer peripheral contour 1Aa is used as the evaluation determination amount. Therefore, the processing of the evaluation determination amount calculation unit 15Bb and the evaluation unit 15Bc in the third embodiment will be described.

[0054] [Evaluation determination amount calculation unit 15Bb] The evaluation determination amount calculation unit 15Bb sets a reference point H in the image data within the area surrounded by the detected outer peripheral contour 1Aa, as shown in Fig. 20. Then, one or more distances L from the reference point H to the outer peripheral contour 1Aa in one or more directions K set from the reference point H are calculated as the evaluation determination amount. The distance L is a straight-line distance in the image. An example of multiple directions K is shown in Fig. 21. The above direction K is, for example, one or more directions for each side, that is, four or more directions. For example, it is 20 or more directions.

[0055] [Setting reference point H] The reference point H can be set at any position within the area surrounded by the detected outer peripheral contour 1Aa. The reference point H may be the center of gravity of the detected contour 1Aa, or may be any coordinate within the contour 1Aa of the molded part 1A if the molded part 1A can always be installed in the same position and imaged.

[0056] [Measurement of distance L from reference point H to contour 1Aa in one direction K] A method for measuring the distance L from the reference point H to the contour 1Aa in one direction K will be described with reference to FIG. As shown in Figure 20, the coordinates of a reference point H at an arbitrary position are set. Next, the direction K for measuring the distance L to the contour 1Aa is defined. The measurement direction K is defined using the angle θ from the reference line LH, and in Figure 20, the line pointing upward from the reference point H is defined as the reference line LH with θ = 0°. When a straight line is drawn from the reference point H in the measurement direction K, the length of the line until it intersects with the contour 1Aa is calculated as the measurement distance L in the measurement direction K. For example, the length of the line is found as the distance L from the coordinates of the reference point H and the coordinates of the position where the line intersects with the contour 1Aa.

[0057] [Measurement of all directions of the panel] The measurement of the above straight line is repeated along the entire circumference of the workpiece 1 for the number of directions K. For example, the angle θ defining the measurement direction K is changed in 1° increments within the range of 0 to 359°, and the distance L from the reference point H to the contour 1Aa is measured. In this case, the calculation process of the measurement direction K and the measurement distance L is repeated 360 times. The measurement direction K may be defined at any equal intervals, or, depending on the molded part 1A, may be set to a predetermined measurement direction K even if it is not at equal intervals (FIG. 21). Here, the position of the reference point H is set to the same standard and is applied to all of the molded parts that serve as the reference and the mass-produced products that are to be evaluated.

[0058] The measurement direction K is also adjusted so that the same reference orientation is set as the base point for the reference molded part 1A and the workpiece 1 of each press-molded molded part 1A. For example, the orientation of the workpiece 1 is set to be the same when imaging, and then imaging is performed. Alternatively, image processing is performed so that the orientation of the captured image data is in the same direction K. For example, the orientation of the molded part 1A is determined based on the orientation of the four corner positions of each tube formed by draw molding.

[0059] [Evaluation Section 15Bc] The evaluation unit 15Bc evaluates the molding inflow amount based on the evaluation determination amount (measurement direction K and measurement length), which is a feature amount calculated by the evaluation determination amount calculation unit 15Bb. In this embodiment, the evaluation of the molding inflow amount is performed for each measurement direction K. The molding inflow amount may be evaluated using the sum of the multiple evaluation and determination quantities. In this case, the molding inflow amount for the entire molded part 1A can be evaluated. In contrast, if the amount is evaluated for each measurement direction K, it becomes possible to detect the location of an abnormal change in the inflow amount. Although the measurement direction K may be one direction, in this embodiment, measurements are taken in multiple directions.

[0060] The evaluation unit 15Bc, for example, calculates the difference between a reference evaluation amount, which is a preset reference evaluation amount, and the evaluation determination amount calculated by the evaluation determination amount calculation unit 15Bb, and evaluates the molding inflow amount based on the difference. For example, if the calculated difference is equal to or greater than a preset threshold, the evaluation unit 15Bc determines that the molding inflow amount is abnormal. There is a positive correlation between the measurement length (distance L) in the measurement direction K and the amount of material inflow in the measurement direction K due to press forming. In other words, the evaluation determination amount is an index value that defines the amount of material inflow, which is proportional to the amount of material inflow. In this embodiment, by setting multiple measurement directions K, the amount of inflow at multiple locations along the circumferential direction of the workpiece 1 can be individually evaluated. The reference evaluation amount may be obtained in advance by conducting an experiment or the like.

[0061] Furthermore, in the case of equipment that sequentially press-forms workpieces 1 of the same shape into the same press parts, the reference evaluation amount may be set as follows. Note that this equipment is mass production equipment that manufactures the same press parts. In this case, the reference evaluation amount for the current evaluation may be the average value of the evaluation judgment amounts obtained before the press forming to be evaluated (the evaluation judgment amounts for the first few times may also be used), or the evaluation judgment amount obtained immediately before. In this case, it is possible to evaluate changes from past press forming, and to detect molding defects in the process of sequentially manufacturing mass-produced products from changes in the amount of material inflow due to press forming. The rest is the same as in the first embodiment. However, in this third embodiment, by setting a plurality of measurement directions K, it is possible to individually evaluate the molding inflow amounts at a plurality of locations along the circumferential direction of the workpiece 1.

[0062] (Variation) Alternatively, for example, the evaluation process may be performed as follows: First, the validity of the molding inflow rate is determined based on the total value of the evaluation determination amount (measured distance L) for each direction K. Then, only if the molding inflow rate is determined to be abnormal, the evaluation determination amount (measured distance L) for each direction K may be evaluated to identify the location of the molding inflow rate abnormality. Similarly, the evaluation process may be performed as follows: That is, the validity of the molding inflow rate of the entire molded part 1A is evaluated using the evaluation method of the first or second embodiment. Then, only if the molding inflow rate is determined to be abnormal, the evaluation method of the third embodiment may be used to evaluate the evaluation judgment amount (measured distance L) for each direction K, and the location of the molding inflow rate abnormality may be identified.

[0063] (others) The present disclosure may also have the following configuration. (1) A method for evaluating a molding inflow amount, which is the amount of material that flows in by press molding when a workpiece is press-molded to produce a pressed part, comprising: After press forming, the workpiece is photographed from the thickness direction of the workpiece, Detecting an outer peripheral contour of the workpiece after the press forming from the captured image data; calculating an evaluation determination amount for evaluating the molding inflow amount based on the captured image data and the detected outer peripheral contour; The molding inflow amount is evaluated based on the calculated evaluation determination amount. A molding inflow rate evaluation method characterized by:

[0064] (2) The evaluation determination quantity is the area within the outer peripheral contour. (3) The evaluation determination quantity is the perimeter of the outer peripheral contour. (4) The evaluation is performed by calculating the difference between the reference evaluation amount, which is a set reference evaluation amount, and the calculated evaluation judgment amount, and evaluating the molding inflow amount based on this difference. (5) When workpieces of the same shape are press-molded into the same press parts in sequence, For each workpiece after press forming, an evaluation determination amount is determined by the method described in claim 2 or claim 3, and a change in the forming inflow amount is evaluated based on the determined multiple evaluation determination amounts. (6) A method for manufacturing a pressed part, in which workpieces of the same shape are press-molded into the same pressed part in sequence, thereby successively manufacturing the pressed parts, An inspection process is provided in which each workpiece after molding is evaluated using the molding inflow amount evaluation method of the present disclosure, and the validity of the molding inflow amount is inspected based on whether or not the difference between the reference evaluation amount and the evaluation judgment amount is within a predetermined range. A method for manufacturing a pressed part.

[0065] (7) The evaluation determination amount is the contour shape of the outer peripheral contour. (8) The evaluation is performed by calculating the similarity between the set reference contour shape and the contour shape that is the evaluation determination amount, and evaluating the molding inflow amount based on the calculated similarity. (9) A method for manufacturing a pressed part, in which workpieces of the same shape are press-molded sequentially into the same pressed part, to sequentially manufacture the pressed part, Each workpiece after forming is evaluated using the forming inflow amount evaluation method of the present disclosure, The method further includes an inspection step of inspecting the validity of the molding inflow amount based on whether or not the similarity is within a preset range. (10) In the image data, a reference point is set within an area surrounded by the detected outer contour; The evaluation determination amount is one or more distances from the reference point to the outer peripheral contour in one or more directions set from the reference point.

[0066] (11) The direction in which the evaluation determination amount is calculated is set to two or more directions, and the distance is calculated for each direction. The evaluation is performed by comparing the reference distance set for each of the directions with the distance that is the evaluation determination amount, thereby evaluating the molding inflow amount at each of the multiple positions. (12) When workpieces of the same shape are press-molded sequentially into the same press parts, For each workpiece after press forming, an evaluation determination amount is determined by the method described in claim 10 or claim 11, and a change in the forming inflow amount is evaluated based on the determined multiple evaluation determination amounts. (13) A method for manufacturing a pressed part, in which workpieces of the same shape are press-molded into the same pressed part in sequence, to sequentially manufacture the pressed parts, Each workpiece after forming is evaluated using the forming inflow amount evaluation method of the present disclosure, and an inspection step of inspecting the validity of the molding inflow amount based on whether or not a difference between a reference distance and the distance that is the evaluation determination amount is within a preset range for each of the directions. A method for manufacturing a pressed part.

[0067] (14) A molding inflow amount evaluation device for evaluating a molding inflow amount, which is an inflow amount of material by press molding when a workpiece is press-molded to manufacture a press part, comprising: an imaging device that images the workpiece after press forming from the plate thickness direction of the workpiece; a contour detection unit that detects an outer peripheral contour of the workpiece after the press forming from the captured image data; and an evaluation determination amount calculation unit that calculates an evaluation determination amount for evaluating the molding inflow amount based on the captured image data and the detected outer peripheral contour; an evaluation unit that evaluates the molding inflow amount based on the calculated evaluation determination amount; A molding inflow rate evaluation device comprising:

[0068] (15) The evaluation determination amount calculation unit calculates the area surrounded by the outer peripheral contour as the evaluation determination amount. (16) The evaluation determination amount calculation unit calculates the outer periphery length of the outer periphery contour, which is the total length along the outer periphery contour, as the evaluation determination amount. (17) The evaluation unit calculates the difference between the reference evaluation amount, which is the set reference evaluation amount, and the evaluation determination amount calculated by the evaluation determination amount calculation unit, and evaluates the molding inflow amount based on the difference. (18) A molding inflow rate evaluation device provided in equipment for press-molding workpieces of the same shape into the same press parts in sequence, a storage unit that sequentially stores the evaluation determination amounts calculated by the evaluation determination amount calculation unit; The evaluation unit evaluates the change in molding inflow amount based on a plurality of evaluation determination amounts stored in the storage unit. (19) A press part manufacturing apparatus that sequentially manufactures press parts by press-molding workpieces of the same shape into identical press parts, Equipped with the molding inflow rate evaluation device of the present disclosure, The molding inflow rate evaluation device evaluates the validity of the molding inflow rate for each workpiece after molding based on whether or not the difference between the reference evaluation amount and the evaluation determination amount is within a preset range. A press part manufacturing device characterized by:

[0069] (20) The evaluation determination amount calculation unit calculates the contour shape of the outer peripheral contour as the evaluation determination amount. (21) The evaluation unit calculates the similarity between the set reference contour shape and the contour shape that is the evaluation determination amount, and evaluates the molding inflow amount based on the calculated similarity. (22) A molding inflow rate evaluation device provided in equipment for press-molding workpieces of the same shape into the same press parts in sequence, comprising: a storage unit that sequentially stores the evaluation determination amounts calculated by the evaluation determination amount calculation unit; The evaluation unit evaluates the validity of the molding inflow amount based on a plurality of evaluation determination amounts stored in the storage unit, depending on whether the similarity is within a preset range.

[0070] (23) The evaluation judgment quantity calculation unit sets a reference point within the area surrounded by the detected outer contour in the image data, and calculates one or more distances from the reference point to the outer contour in one or more directions set from the reference point as the evaluation judgment quantity. (24) The evaluation determination amount calculation unit calculates the distance for each of two or more directions for which the evaluation determination amount is calculated, The evaluation unit compares the reference distance set for each of the directions with the distance that is the evaluation determination amount, thereby evaluating the molding inflow amount at each of the multiple positions.

[0071] (25) A molding inflow rate evaluation device provided in equipment for press-molding workpieces of the same shape into the same press parts in sequence, a storage unit that sequentially stores the evaluation determination amounts calculated by the evaluation determination amount calculation unit; The evaluation unit evaluates the change in molding inflow amount based on a plurality of evaluation determination amounts stored in the storage unit. (26) A press part manufacturing apparatus that sequentially manufactures press parts by press-molding workpieces of the same shape into the same press parts, The molding inflow rate evaluation device according to claim 23 or 24 is provided, The molding inflow volume evaluation device evaluates the validity of the molding inflow volume for each workpiece after molding based on whether the difference between the reference distance and the distance that is the evaluation judgment volume for each of the above directions is within a predetermined range. [Example]

[0072] Next, an example of this embodiment will be described. (Example of the first embodiment) Using the same mold and workpiece 1 (blank) under the same conditions, molded parts 1A were obtained by square tube draw forming under different press forming conditions. Next, the details will be explained. <Work 1> The workpiece 1 used was a cold-rolled mild steel sheet with a tensile strength of 270 MPa. The steel sheet had a thickness of 0.7 mm. The cold-rolled mild steel sheet was then cut into a square of 200 mm on each side to prepare the test piece (workpiece 1). For lubrication, the general-purpose rust preventative oil Preton R352L was applied to both sides of the test piece.

[0073] <Press molding> The test piece was draw-formed using a rectangular tube draw-forming die shown in Fig. 10 to obtain a molded part 1A. The shape of the molded part 1A was as shown in Fig. 6. The punch 10 used was a square with sides of 100 mm, with the four corners rounded with a radius of 25 mm and the punch shoulder rounded with a radius of 12 mm. The clearance with the die 21 was 2.1 mm, and the die shoulder rounded with a radius of 10 mm. The press forming speed was approximately 20 mm / sec, and the forming height was uniformly set to 35 mm.

[0074] <Press molding conditions> The molding conditions for each sample are shown in Table 1. [Table 1]

[0075] That is, in Samples No. 1 to 5, the blank holding force (BHF) of the blank holder 20 was changed to change the press forming conditions. For sample No. 6, the blank holding force (BHF) of the blank holder 20 was set to 200 kN. Furthermore, for sample No. 6, a poly sheet 30 was attached to a portion of the test piece as shown in Figure 11, and press forming was performed. The poly sheet 30 was attached as a disturbance during press forming. The poly sheet 30 was attached to both sides of the test piece, with a thickness of approximately 0.1 mm and a size of 20 mm square. The attachment positions were as shown in Figure 11. For each sample condition, press molding was performed twice to obtain molded parts 1A.

[0076] <Evaluation> Each of the obtained molded parts 1A was placed on a black screen and an image was taken with a single-lens reflex camera 11. The camera 11 was placed in a position where the focus was on the top of the molded part 1A (the bottom of the part). As shown in Figure 12(a), the images were taken not only with the molded part 1A facing the same direction as during draw molding, but also with the molded part 1A rotated at an arbitrary angle, as shown in Figure 12(b), and multiple images were taken in each direction. Then, the image of each molded part 1A was subjected to image processing, and the contour inner area and contour outer periphery length of each molded part 1A (workpiece 1 after molding) were calculated.

[0077] The relationship between the area within the detected contour 1Aa and the BHF for Samples No. 1 to 5 is shown in Fig. 13. Furthermore, the relationship between the detected contour perimeter and the BHF for Samples No. 1 to 5 is shown in Fig. 14. 13 and 14 show that both the inner contour area and the contour periphery length tend to increase with increasing BHF. This is because increasing BHF reduces the material inflow during rectangular tube draw forming.

[0078] Furthermore, since the contour perimeter length showed a tendency to converge at BHF > 150 kN, measuring the contour area of ​​formed part 1A was more sensitive in detecting changes in press forming conditions, i.e., changes in the amount of material flowing in. Next, the evaluation results of samples No. 4 and No. 6, which have the same BHF, are compared. Figure 15 shows the relationship between the contour inner area when the lubrication conditions are R352L (No. 4) and when poly sheet 30 is mixed in (No. 6) under the same BHF condition. Figure 16 shows the relationship between the contour outer periphery length when the lubrication conditions are R352L (No. 4) and when poly sheet 30 is mixed in (No. 6) under the same BHF condition.

[0079] The area inside the contour of the molded part 1A is slightly reduced by mixing in the poly sheet 30. The poly sheet 30 is about 0.1 mm thick, and only the areas of the test specimen where the poly sheet 30 is inserted are tightly sandwiched between the die 21 and the blank holder 20, while the pressure from the die 21 and the blank holder 20 is weaker in other areas. This causes an overall increase in the inflow amount. On the other hand, the contour perimeter of molded part 1A was measured to be about the same length regardless of whether or not poly sheet 30 was mixed in. This result also shows that in order to detect slight changes in molding conditions due to the mixing in of 20 mm square poly sheet 30, it is more effective to evaluate the contour inner area than the contour perimeter.

[0080] (Example of the second embodiment) An example based on the second embodiment will be described below. <Work 1>, <Press molding>, <Press molding conditions> These conditions were the same as those in the first embodiment.

[0081] <Evaluation> The molded part 1A of sample No. 4, which was molded in the first press, was designated as the reference molded part 1A. The contour shape of this reference molded part 1A was then set as the reference contour shape. Then, the other molded part 1A was used as the measurement target part to calculate the similarity. The similarity was calculated using the matchShapes function, which is an OpenCV contour shape calculation function, and the mode was calculated using I1(A,B) shown in the above formula (1). Here, the similarity of the reference molded part 1A itself calculated using this mode is I1(A,A) = 0, so the closer the similarity is to zero, the more similar the contour shape is.

[0082] The relationship between the similarity and BHF obtained using samples No. 1 to No. 5 is shown in FIG. In this example, the molded part 1A under the molding conditions shown in No. 4 of Table 1 as described above is the reference molded part 1A, which is the first molded part 1A under N1 (the first molded part). Therefore, the value indicating the similarity of the molded part 1A under the same molding conditions under N2 (the second molded part) is the lowest, making it the most similar in relative terms. It was also confirmed that the value indicating the similarity tends to increase as the BHF deviates from 200 kN, meaning that the parts become more dissimilar. Therefore, it was found that it is possible to detect changes in press molding conditions by calculating the similarity between the contour shape of the reference molded part 1A and the contour shape of the molded part 1A to be measured.

[0083] Additionally, samples No. 4 and No. 6 were compared. Figure 19 shows the relationship between the similarity and the lubrication conditions when the BHF is 200 kN and the lubrication conditions are R352L (No. 4) and when poly sheet 30 is mixed in (No. 6). As can be seen from Figure 19, when poly sheet 30 was mixed in, the value indicating the similarity increased. In other words, the similarity decreased. The poly sheet 30 was about 0.1 mm thick, and only the area of ​​the test specimen where the poly sheet 30 was inserted was tightly sandwiched between the die 21 and the blank holder 20. In other areas, the pressure from the die 21 and the blank holder 20 was weaker, so the inflow amount increased overall. This is because the contour shape deviated slightly from that of the reference molded part 1A.

[0084] These results also show that calculating the similarity of the contour shape of the molded part 1A to be measured to the contour shape of the reference molded part 1A is effective in detecting slight changes in molding conditions due to the inclusion of a 20 mm square poly sheet 30.

[0085] (Example of the third embodiment) An example based on the third embodiment will be described below. <Work 1>, <Press molding>, <Press molding conditions> These conditions were the same as those in the first embodiment. However, the images were taken at the positions shown in FIG. 12, and each molded part 1A was placed so that it faced the same direction as during draw molding.

[0086] <Evaluation> For each molded part 1A, the distance L from the reference point H to the contour 1Aa was measured over the entire circumference of the molded part 1A. Here, the center of gravity of the detected contour 1Aa is set as the reference point H. In addition, the angle θ = 0° in the upward direction from the reference point H, and the distance L to the contour 1Aa was measured in a measurement direction K (360 direction K in this example) in which θ = 0 to 359° was changed in 1° increments. At this time, the relationship between the angle θ, which is the index value of the measurement direction K, and the measured distance L in that direction K was converted into a data frame and saved in a database.

[0087] The evaluation results of samples No. 1 to 5 will be explained. FIG. 22 shows the relationship between the distance L from the reference point H to the contour 1Aa and the measurement direction K, calculated by image processing of the molded part 1A molded with the BHF varied between 50 and 250 kN. As can be seen from Fig. 22, regardless of the size of the BHF, the distance L from the reference point H to the contour 1Aa is long in the measurement directions K (the directions of the corners of the workpiece 1) of 45°, 135°, 224°, and 315°. On the other hand, it can be seen that the distance L is shorter in the measurement directions K between these angles, that is, the four sides.

[0088] Furthermore, as the BHF increased, there was no significant change in the distribution pattern of the distance L from the reference point H to the contour 1Aa, and an overall upward shift was observed. Therefore, the measurement results show that the increase in BHF does not significantly change the inflow balance, but rather reduces the overall inflow volume. Next, the evaluation results of samples Nos. 4 and 6 will be described. FIG. 23 shows the relationship between the length from the reference point H to the contour 1Aa and the measurement direction K under the condition of a constant BHF of 200 kN and the lubrication conditions of the presence or absence of the poly sheet 30 described above.

[0089] As can be seen from Figure 23, when press molding is performed with a 20mm square poly sheet 30 mixed in as a disturbance, the distribution pattern of the length from the reference point H to the outline 1Aa is almost the same as when there is no poly sheet 30. However, a slight difference in the inflow rate was confirmed near the measurement direction Kθ = 270°. Near θ = 270° is the position exactly opposite the position where the poly sheet 30 was mixed in, as shown in Figure 11, across the center of the test piece.

[0090] The mixed area of ​​the poly sheet 30 has a partially increased thickness, which results in strong wrinkle suppression, but conversely, the area other than the poly sheet 30 is relatively thin, which makes it difficult to suppress wrinkles, and therefore an increase in the inflow amount is predicted. The measurement results show that when poly sheet 30 is present, the distance L from reference point H to contour 1Aa is shorter around θ = 270°, on the opposite side of the poly sheet 30 mixing position, and therefore the inflow volume increases as predicted.

[0091] From the above, the contour shape of the workpiece 1 after press forming is detected by image processing of the molded part 1A after press forming, and the distance L from the reference point H set within the contour 1Aa to the contour 1Aa is measured over the entire periphery of the panel. This demonstrates that it is possible to measure the change in the inflow rate of the entire molded part 1A and the position where the inflow rate is changing. [Explanation of symbols]

[0092] 1 Work 1A Molded part (workpiece after molding) 1A Press-molded parts 1Aa Contour 11 Camera 12 Lighting equipment 14 Mounting table 14 14a Placement surface 15 Control Computer 15A input / output section 15B Processing unit 15Ba Contour detection unit 15Bb Evaluation judgment amount calculation unit 15Bc Evaluation Department 15C Memory Section H reference point Similarity of I1, I2, I3 K direction L distance θ angle

Claims

1. A method for evaluating a molding inflow amount, which is an inflow amount of material by press molding, when a workpiece is press-molded to produce a press part, comprising: After press forming, the workpiece is photographed from the thickness direction of the workpiece, Detecting an outer peripheral contour of the workpiece after the press forming from the captured image data; calculating an evaluation determination amount for evaluating the molding inflow amount based on the captured image data and the detected outer peripheral contour; The molding inflow amount is evaluated based on the calculated evaluation determination amount, the evaluation determination amount is the area within the outer peripheral contour, When workpieces of the same shape are press-molded into the same press parts in sequence, The evaluation determination amount is calculated for each workpiece after press forming, and a change in the molding inflow amount is evaluated based on the calculated evaluation determination amounts. A molding inflow rate evaluation method characterized by:

2. The evaluation is performed by calculating the difference between the reference evaluation amount, which is a set reference evaluation amount, and the calculated evaluation judgment amount, and evaluating the molding inflow amount based on the difference.

2. The molding inflow rate evaluation method according to claim 1, wherein the molding inflow rate is determined based on the molding inflow rate.

3. A method for manufacturing a pressed part, in which workpieces having the same shape are press-molded sequentially into identical pressed parts, thereby sequentially manufacturing pressed parts, The method for evaluating the molding inflow amount of each workpiece after molding is described in claim 2, and the inspection step is performed to check the validity of the molding inflow amount based on whether the difference between the reference evaluation amount and the evaluation judgment amount is within a predetermined range. A method for manufacturing a pressed part.

4. A method for evaluating a molding inflow amount, which is an inflow amount of material by press molding, when a workpiece is press-molded to produce a press part, comprising: After press forming, the workpiece is photographed from the thickness direction of the workpiece, Detecting an outer peripheral contour of the workpiece after the press forming from the captured image data; calculating an evaluation determination amount for evaluating the molding inflow amount based on the captured image data and the detected outer peripheral contour; The molding inflow amount is evaluated based on the calculated evaluation determination amount, The evaluation determination amount is the perimeter length of the outer peripheral contour. A molding inflow rate evaluation method characterized by:

5. The evaluation is performed by calculating the difference between the reference evaluation amount, which is a set reference evaluation amount, and the calculated evaluation judgment amount, and evaluating the molding inflow amount based on the difference.

5. The method for evaluating the molding inflow rate according to claim 4.

6. When workpieces of the same shape are press-molded into the same press parts in sequence, For each workpiece after press forming, an evaluation determination amount is obtained by the method described in claim 4, and a change in the molding inflow amount is evaluated based on the obtained multiple evaluation determination amounts. A molding inflow rate evaluation method characterized by:

7. A method for manufacturing a pressed part, in which workpieces having the same shape are press-molded sequentially into identical pressed parts, thereby sequentially manufacturing pressed parts, The method for evaluating the molding inflow amount of each workpiece after molding is described in claim 5, and the inspection step is performed to check the validity of the molding inflow amount based on whether the difference between the reference evaluation amount and the evaluation judgment amount is within a predetermined range. A method for manufacturing a pressed part.

8. A method for evaluating a molding inflow amount, which is an inflow amount of material by press molding, when a workpiece is press-molded to produce a press part, comprising: After press forming, the workpiece is photographed from the thickness direction of the workpiece, Detecting an outer peripheral contour of the workpiece after the press forming from the captured image data; calculating an evaluation determination amount for evaluating the molding inflow amount based on the captured image data and the detected outer peripheral contour; The molding inflow amount is evaluated based on the calculated evaluation determination amount, In the image data, a reference point is set within an area surrounded by the detected outer peripheral contour; The evaluation determination amount is one or more distances from the reference point to the outer peripheral contour in one or more directions set from the reference point. A molding inflow rate evaluation method characterized by:

9. The direction in which the evaluation determination amount is to be obtained is set to two or more directions, and the distance is obtained for each direction; The evaluation is performed by comparing the reference distance set for each of the directions with the distance that is the evaluation determination amount, thereby evaluating the molding inflow amount at each of the multiple positions.

9. The molding inflow rate evaluation method according to claim 8.

10. When workpieces of the same shape are press-molded into the same press parts in sequence, For each workpiece after press forming, an evaluation determination amount is obtained by the method according to claim 8 or claim 9, and a change in the molding inflow amount is evaluated based on the obtained plurality of evaluation determination amounts. A molding inflow rate evaluation method characterized by:

11. A method for manufacturing a pressed part, in which workpieces having the same shape are press-molded sequentially into identical pressed parts, thereby sequentially manufacturing pressed parts, Each workpiece after molding is evaluated by the molding inflow amount evaluation method according to claim 8 or claim 9, and an inspection step of inspecting the validity of the molding inflow amount based on whether or not a difference between a reference distance and the distance that is the evaluation determination amount is within a preset range for each of the directions. A method for manufacturing a pressed part.

12. A molding inflow rate evaluation device that evaluates a molding inflow rate, which is the amount of material that flows in by press molding when a workpiece is press-molded to produce a press part, and that is installed in equipment that press-moldes workpieces of the same shape into identical press parts in sequence, an imaging device that images the workpiece after press forming from the plate thickness direction of the workpiece; a contour detection unit that detects an outer peripheral contour of the workpiece after the press forming from the captured image data; and an evaluation determination amount calculation unit that calculates an evaluation determination amount for evaluating the molding inflow amount based on the captured image data and the detected outer peripheral contour; an evaluation unit that evaluates the molding inflow amount based on the calculated evaluation determination amount; Equipped with the evaluation determination amount calculation unit calculates an area surrounded by the outer peripheral contour as an evaluation determination amount; a storage unit that sequentially stores the evaluation determination amounts calculated by the evaluation determination amount calculation unit; The evaluation unit evaluates the change in molding inflow amount based on a plurality of evaluation determination amounts stored in the storage unit. A molding inflow rate evaluation device characterized by:

13. The evaluation unit calculates a difference between a reference evaluation amount, which is a set reference evaluation amount, and the evaluation determination amount calculated by the evaluation determination amount calculation unit, and evaluates the molding inflow amount based on the difference.

13. The molding inflow rate evaluation device according to claim 12.

14. A press part manufacturing apparatus that sequentially manufactures press parts by press-molding workpieces of the same shape into identical press parts, The molding inflow rate evaluation device according to claim 13 is provided, The molding inflow rate evaluation device evaluates the validity of the molding inflow rate for each workpiece after molding based on whether or not the difference between the reference evaluation amount and the evaluation determination amount is within a preset range. A press part manufacturing device characterized by:

15. A molding inflow rate evaluation device that evaluates a molding inflow rate, which is the amount of material that flows in by press molding when a workpiece is press molded to manufacture a press part, an imaging device that images the workpiece after press forming from the plate thickness direction of the workpiece; a contour detection unit that detects an outer peripheral contour of the workpiece after the press forming from the captured image data; and an evaluation determination amount calculation unit that calculates an evaluation determination amount for evaluating the molding inflow amount based on the captured image data and the detected outer peripheral contour; an evaluation unit that evaluates the molding inflow amount based on the calculated evaluation determination amount; Equipped with the evaluation determination amount calculation unit calculates, as the evaluation determination amount, a perimeter length of the outer perimeter contour, which is a total length along the outer perimeter contour; A molding inflow rate evaluation device characterized by:

16. The evaluation unit calculates a difference between a reference evaluation amount, which is a set reference evaluation amount, and the evaluation determination amount calculated by the evaluation determination amount calculation unit, and evaluates the molding inflow amount based on the difference.

16. The molding inflow rate evaluation device according to claim 15.

17. A molding inflow rate evaluation device provided in equipment that press-forms workpieces of the same shape into identical press parts in sequence, a storage unit that sequentially stores the evaluation determination amounts calculated by the evaluation determination amount calculation unit; The evaluation unit evaluates the change in molding inflow amount based on a plurality of evaluation determination amounts stored in the storage unit.

16. The molding inflow rate evaluation device according to claim 15.

18. A press part manufacturing apparatus that sequentially manufactures press parts by press-molding workpieces of the same shape into identical press parts, The molding inflow rate evaluation device according to claim 16 is provided, The molding inflow rate evaluation device evaluates the validity of the molding inflow rate for each workpiece after molding based on whether or not the difference between the reference evaluation amount and the evaluation determination amount is within a preset range. A press part manufacturing device characterized by:

19. A molding inflow rate evaluation device that evaluates a molding inflow rate, which is the amount of material that flows in by press molding when a workpiece is press molded to manufacture a press part, an imaging device that images the workpiece after press forming from the plate thickness direction of the workpiece; a contour detection unit that detects an outer peripheral contour of the workpiece after the press forming from the captured image data; and an evaluation determination amount calculation unit that calculates an evaluation determination amount for evaluating the molding inflow amount based on the captured image data and the detected outer peripheral contour; an evaluation unit that evaluates the molding inflow amount based on the calculated evaluation determination amount; Equipped with the evaluation determination amount calculation unit sets a reference point in the image data within an area surrounded by the detected outer peripheral contour, and calculates, as the evaluation determination amount, one or more distances from the reference point to the outer peripheral contour in one or more directions set from the reference point; A molding inflow rate evaluation device characterized by:

20. the evaluation determination amount calculation unit calculates the distance for each of two or more directions as the direction for which the evaluation determination amount is calculated, the evaluation unit compares the reference distance set for each of the directions with the distance that is the evaluation determination amount, thereby evaluating the molding inflow amounts at the plurality of positions, respectively.

20. The molding inflow rate evaluation device according to claim 19.

21. A molding inflow rate evaluation device provided in equipment that press-forms workpieces of the same shape into identical press parts in sequence, a storage unit that sequentially stores the evaluation determination amounts calculated by the evaluation determination amount calculation unit; The evaluation unit evaluates the change in molding inflow amount based on a plurality of evaluation determination amounts stored in the storage unit.

20. The molding inflow rate evaluation device according to claim 19.

22. A press part manufacturing apparatus that sequentially manufactures press parts by press-molding workpieces of the same shape into identical press parts, The molding inflow rate evaluation device according to claim 19 or 20 is provided, The molding inflow rate evaluation device evaluates the validity of the molding inflow rate for each workpiece after molding based on whether or not the difference between the reference distance and the distance that is the evaluation determination amount is within a preset range for each of the directions. A press part manufacturing device characterized by:

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