JP7053889B2 - Necking determination method for press-molded products, necking determination device for press-molded products, and programs - Google Patents

Description

The present invention relates to a necking determination method for a press-molded product and a necking determination device.

Patent Document 1 identifies the location of a press defect depending on the surface of the object to be inspected by a laser ultrasonic deep scratch device, and analyzes an infrared photographed image of the press defect acquired by the pulse type infrared inspection device. Discloses specifying the size of a press defect. In Patent Document 2, the thickness of a measured object is measured based on the difference between the distance to the measured object measured by two laser displacement meters arranged opposite to each other and the distance between the two laser displacement meters. Is described.

Patent Document 1 Japanese Patent Application Laid-Open No. 2006-170684

Patent Document 2 Japanese Unexamined Patent Publication No. 2010-44027

The problem to be solved

Press-molded products used for automobile skeleton parts and the like may have necking such as a local decrease in plate thickness due to local elongation deformation. It may be difficult to determine the presence or absence of such necking from an image as in Patent Document 1. Further, when a plurality of laser displacement meters are used as in Patent Document 2, it may be difficult to secure an installation space.

General disclosure

The method for determining necking of a press-molded product according to one aspect of the present invention may include a step of acquiring a first waveform indicating a two-dimensional surface shape including a first position of a predetermined portion of the press-molded product. The necking determination method of the press-molded product may include a step of deriving a change amount of the first waveform. The method for determining necking of a press-molded product may include a step of determining whether or not necking occurs at a predetermined portion based on the amount of change in the first waveform.

At the determination stage, if the amount of change satisfies a predetermined change pattern, it may be determined that necking has occurred at a predetermined portion. In the determination step, it may be determined whether or not necking occurs at a predetermined portion based on whether or not the difference per unit distance of the first waveform satisfies a predetermined change pattern. .. In the determination stage, whether or not necking occurs at a predetermined portion based on whether or not the difference per unit distance of the first derivative waveform of the first waveform satisfies a predetermined change pattern. May be determined.

At the derivation stage, the change amount may be derived by differentiating the first waveform.

At the derivation stage, the second-order differential waveform of the first waveform may be derived as a change amount by second-order differentiation of the first waveform. In the determination step, it may be determined whether or not necking occurs at a predetermined portion based on the second-order differential waveform of the first waveform.

In the determination step, it may be determined whether or not necking occurs at a predetermined portion based on the maximum point and the minimum point on the second-order differential waveform of the first waveform.

At the determination stage, is necking occurring at a predetermined site based on the difference between the maximum point and the minimum point that are adjacent to each other on the second derivative waveform of the first waveform and include a zero point in between? It may be determined whether or not.

The acquisition stage is the first position of the predetermined part measured by the laser displacement meter that irradiates the predetermined part of the press-molded product with the laser light and receives the reflected light from the predetermined part. The first waveform showing the two-dimensional surface shape including the above may be acquired.

The laser displacement meter may scan a line laser beam extending in a lateral direction different from the longitudinal direction of a predetermined portion along the longitudinal direction. In the acquisition step, a second waveform indicating a two-dimensional surface shape including a second position different from the first position along the longitudinal direction of a predetermined portion measured by a laser displacement meter may be acquired. At the derivation stage, the second-order differential waveform of the second waveform may be derived by second-order differentiation of the second waveform. In the determination step, it may be determined whether or not necking occurs at a predetermined portion based on the second-order differential waveform of the first waveform and the second-order differential waveform of the second waveform.

The determination stage is adjacent to each other on the second-order differential waveform of the first waveform, and the difference between the maximum point and the minimum point including the zero point in between, and adjacent to each other on the second-order differential waveform of the second waveform. Moreover, when the difference between the maximum point including the zero point and the minimum point is equal to or larger than a predetermined threshold value, a step of determining that necking has occurred in the predetermined portion may be included. The acquisition step may include the step of acquiring the first waveform from the measurement result of the white interferometer using the white light source. The determination step is whether or not the second-order differential waveform of the first waveform satisfies a predetermined waveform pattern indicating that the occurrence of necking is high, and whether or not necking occurs at a predetermined portion. May be determined. The predetermined waveform pattern may be sequentially updated by machine learning the waveform pattern in which necking actually occurs.

The necking determination device for a press-molded product according to one aspect of the present invention may include an acquisition unit that acquires a first waveform indicating a two-dimensional surface shape including a first position of a predetermined portion of the press-molded product. The necking determination device for the press-molded product may include a derivation unit for deriving the amount of change in the first waveform. The necking determination device for the press-molded product may include a determination unit for determining whether or not necking has occurred in a predetermined portion based on the amount of change in the first waveform.

The program according to one aspect of the present invention may be a program for causing a computer to execute the necking determination method of the press-molded article.

The outline of the above invention does not list all the necessary features of the present invention. A subcombination of these feature groups can also be an invention.

It is a figure which shows the schematic structure of the inspection system of a press-molded article. It is a figure which shows an example for demonstrating the method of measuring the part to be the target of the necking inspection of a press-molded article. It is a figure which shows an example of the functional block of the necking determination apparatus which concerns on one Embodiment. It is a figure which shows an example of the waveform measured at an arbitrary position of the part to be the necking inspection, the 1st derivative waveform which differentiated the measured waveform 1st order, and the 2nd derivative waveform which differentiated 2nd order. It is a figure which shows an example of the waveform measured at an arbitrary position of the part to be the necking inspection, the 1st derivative waveform which differentiated the measured waveform 1st order, and the 2nd derivative waveform which differentiated 2nd order. It is a flowchart which shows an example of the procedure for determining the necking of a press-molded article. It is a figure which shows an example of a hardware configuration.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention.

Various embodiments of the present invention may be described with reference to flowcharts and block diagrams, wherein the block is (1) a stage of the process in which the operation is performed or (2) a device having a role of performing the operation. May represent a "part" of. Specific steps and "parts" may be implemented by programmable circuits and / or processors. Dedicated circuits may include digital and / or analog hardware circuits. It may include integrated circuits (ICs) and / or discrete circuits. The programmable circuit may include a reconfigurable hardware circuit. Reconfigurable hardware circuits include logical AND, logical OR, logical XOR, logical NAND, logical NOR, and other logical operations, flip-flops, registers, field programmable gate arrays (FPGA), programmable logic arrays (PLA), etc. It may include a memory element such as.

The computer readable medium may include any tangible device capable of storing instructions executed by the appropriate device. As a result, the computer-readable medium having the instructions stored therein will include the product, including instructions that can be executed to create means for performing the operation specified in the flowchart or block diagram. Examples of computer-readable media may include electronic storage media, magnetic storage media, optical storage media, electromagnetic storage media, semiconductor storage media, and the like. More specific examples of computer-readable media include floppy (registered trademark) disks, diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), Electrically erasable programmable read-only memory (EEPROM), static random access memory (SRAM), compact disc read-only memory (CD-ROM), digital versatile disc (DVD), Blu-ray (RTM) disc, memory stick, integrated A circuit card or the like may be included.

Computer-readable instructions may include either source code or object code written in any combination of one or more programming languages. Source code or object code includes traditional procedural programming languages. Traditional procedural programming languages are assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcodes, firmware instructions, state setting data, or Smalltalk, JAVA®, C ++, etc. It may be an object-oriented programming language, and a "C" programming language or a similar programming language. Computer-readable instructions are used locally or to a local area network (LAN), wide area network (WAN), etc., to the processor or programmable circuit of a general purpose computer, special purpose computer, or other programmable data processing device. ) May be provided. The processor or programmable circuit may execute computer-readable instructions to create means for performing the operations specified in the flowchart or block diagram. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, and the like.

FIG. 1 is a diagram showing a schematic configuration of an inspection system 1 of a press-molded product 800. The inspection system 1 includes a control device 100, a tracking image pickup unit 200, a necking measurement unit 300, an appearance image pickup unit 400, an alignment processing unit 500, a belt conveyor 700, a good product container 900, and a defective product container 902. The control device 100 is an example of a necking determination device.

The tracking image pickup unit 200, the necking measurement unit 300, the appearance image pickup unit 400, the alignment processing unit 500, and the belt conveyor 700 may be connected to the control device 100 via the network 600. The belt conveyor 700 conveys the press-formed product 800 to a position where processing by the tracking image pickup unit 200, the necking measurement unit 300, the appearance image pickup unit 400, and the alignment processing unit 500 is performed. The press-molded product 800 is manufactured by press-molding a plate material made of a metal material such as hard steel, mild steel, aluminum, titanium or copper by a press molding apparatus. The press-molded product 800 is, for example, an automobile skeleton part or the like.

The inspection system 1 executes a step of specifying the position information of a predetermined portion of the press-molded product 800 based on the image of the press-molded product 800 captured by the tracking image pickup unit 200. The control device 100 provides the necking measurement unit 300 with position information of the specified site to be inspected for necking. The belt conveyor 700 conveys the press-molded product 800 to a position where processing by the necking measuring unit 300 is performed.

Next, the inspection system 1 uses the necking measurement unit 300 to execute a step of determining whether or not necking has occurred in a predetermined portion of the press-molded product 800. The necking measurement unit 300 has a parallel link unit 310 and a displacement measurement unit 320. The parallel link unit 310 has a link mechanism. The link mechanism may be composed of three pairs of links. Each pair of links may be placed in parallel with each other.

The displacement measuring unit 320 has a laser displacement meter connected to a link mechanism. The laser displacement meter may be a two-dimensional laser displacement meter. The necking measurement unit 300 operates three pairs of links based on the position information provided by the control device 100, and aligns the laser displacement meter with the measurement position of the portion to be the target of the necking inspection. The laser displacement meter may be arranged only on one side of the press-molded product 800 to be inspected for necking in the thickness direction. The laser displacement meter irradiates a portion of the press-molded product 800 to be inspected for necking with laser light, and receives the reflected light from that portion. The laser displacement meter measures the two-dimensional surface shape including the measurement position of the part to be the necking inspection from the reflected light.

The control device 100 acquires a waveform indicating a two-dimensional surface shape including a measurement position of a portion to be inspected for necking, which is measured by a laser displacement meter. In the control device 100, based on the acquired waveform, necking such that the plate thickness is locally reduced or cracks are locally generated due to local elongation deformation occurs at the site to be the target of the necking inspection. Determine if it is. The belt conveyor 700 conveys the press-molded product 800 to a position where processing by the appearance imaging unit 400 is performed.

Next, the inspection system 1 is a step of determining the presence or absence of defective parts such as scratches, dents, distortions, cracks, and stains on the press-molded product 800 based on the image of the press-molded product 800 imaged by the appearance imaging unit 400. To execute. The control device 100 receives the image of the press-molded product 800 transmitted by the appearance imaging unit 400. Based on the received image of the press-molded product 800, the control device 100 may determine whether or not defective portions such as scratches, dents, distortions, cracks, and stains are present in the press-molded product 800. Based on the determination result, the control device 100 transmits to the alignment processing unit 500 instruction information to move the press-molded product 800 to the non-defective product container 900 or the defective product container 902. The belt conveyor 700 conveys the press-molded product 800 to a position where processing is performed by the alignment processing unit 500.

Finally, the inspection system 1 executes a step of distributing the press-molded product 800 into the non-defective product container 900 and the defective product container 902 using the alignment processing unit 500. The alignment processing unit 500 has a parallel link unit 510 and a gripper unit 520. The parallel link unit 510 has a link mechanism, and the link mechanism may be composed of three pairs of links. Each pair of links may be placed in parallel with each other. The gripper portion 520 has a gripper that holds the press-molded product 800 by magnetic attraction. According to the instruction information received from the control device 100, the alignment processing unit 500 accommodates the press-molded product 800 determined to have no defective portion, that is, a non-defective product, in the non-defective container 900. On the other hand, the alignment processing unit 500 accommodates the press-molded product 800, which has a defective portion, that is, is determined to be a defective product, in the defective product container 902.

FIG. 2 is a diagram showing an example for explaining a method for measuring a portion of a press-molded product 800 to be inspected for necking. The part to be the target of the necking inspection is a predetermined part. The portion 810 that is the target of the necking inspection shown in FIG. 2 is, for example, a portion of the end portion of the press-molded product 800 that has been drawn. In FIG. 2, the area inside the two dotted lines including the drawn portion is shown as the range to be the target of the necking inspection. In one embodiment, the direction perpendicular to the drawing direction of the portion of the press-molded product 800 that has been drawn is defined as the longitudinal direction 812.

The portion to be inspected for necking may be determined based on the shape of the die of the press-molded product. For the part to be inspected for necking, the plate thickness is locally increased by local elongation deformation by simulating changes in the shape of parts formed in press working using a simulation device that calculates fracture prediction. It may be a site determined to be a site where necking is likely to occur, such as a decrease or a local crack. The portion to be inspected for necking may be a portion specified by the operator as a portion in which necking is likely to occur in a press-molded product similar to a part to be press-molded.

The laser displacement meter 324 irradiates the site 810 with a band-shaped line laser beam 325 and receives the reflected light 326. Necking can occur, for example, along the longitudinal direction 812 of the drawn portion 810. The laser displacement meter 324 may move along the longitudinal direction 812 and sequentially irradiate the site 810 with line laser light 325 to measure the two-dimensional surface shape of a plurality of points in the site 810. The laser displacement meter 324 irradiates the site 810 with the line laser beam 325 so that the width direction 327 of the band-shaped line laser beam 325 is different from the longitudinal direction 812 of the site 810. The laser displacement meter 324 may irradiate the site 810 with the line laser beam 325 so that the widthwise 327 of the strip-shaped line laser beam 325 intersects the longitudinal direction 812 of the site 810. The laser displacement meter 324 may irradiate the site 810 with the line laser beam 325 so that the width direction of the band-shaped line laser beam 325 is perpendicular to the longitudinal direction 812 of the site 810. When the site 810 extends in a curved line, the laser displacement meter 324 has a band-shaped line with respect to the tangent of the point where the straight line in the width direction 327 of the band-shaped line laser beam 325 intersects the curve in the longitudinal direction 812 of the site 810. The site 810 may be irradiated with the line laser beam 325 so that the straight line in the width direction 327 of the laser beam 325 is vertical. In this embodiment, an example in which the laser displacement meter 324 is moved to the portion 810 of the press-molded product 800 and the line laser beam 325 is irradiated to the portion 810 will be described. However, by moving the press-molded product 800, the site 810 may be irradiated with the line laser beam 325 of the laser displacement meter 324 installed at a predetermined position. Further, by moving the laser displacement meter 324 and the press-molded product 800 to each other, the line laser beam 325 of the laser displacement meter 324 may be applied to the portion 810.

The parallel link unit 310 operates three pairs of links based on the position information provided by the control device 100, and the laser displacement meter 324 of the displacement measurement unit 320 is located at the longitudinal end of the site to be inspected for necking. Align. The laser displacement meter 324 may be arranged only on one side of the press-molded product 800 to be inspected for necking in the thickness direction. The laser displacement meter 324 irradiates a line laser beam extending in the lateral direction different from the longitudinal direction of the portion to be inspected for necking along the longitudinal direction. The parallel link unit 310 moves the laser displacement meter 324 along the longitudinal direction. The waveform measured by the laser displacement meter 324 shows the two-dimensional surface shape in the lateral direction at an arbitrary position of the part to be inspected for necking.

FIG. 3 is a diagram showing an example of a functional block of the necking determination device according to the embodiment. The control device 100 includes a main control unit 110, a necking inspection unit 120, a tracking unit 130, and an appearance inspection unit 140. The necking inspection unit 120 includes a displacement acquisition unit 122, a lead-out unit 124, and a necking determination unit 126. The appearance inspection unit 140 has an image acquisition unit 142 and an appearance determination unit 144. The main control unit 110 may be connected to the necking inspection unit 120, the tracking unit 130, and the visual inspection unit 140 via a bus. In one embodiment, the control device 100 is an example of a necking determination device or a computer. The necking inspection unit 120 and the displacement acquisition unit 122 are examples of the inspection unit and the acquisition unit, respectively. Each of the main control unit 110, the necking inspection unit 120, the tracking unit 130, and the visual inspection unit 140 may be configured by separate computers.

The main control unit 110 may be connected to the tracking image pickup unit 200, the parallel link unit 310, the displacement measurement unit 320, the appearance image pickup unit 400, the parallel link unit 510, and the gripper unit 520 via the network 600. The parallel link unit 310 has a control unit 312 and a link unit 314. The displacement measuring unit 320 has a control unit 322 and a laser displacement meter 324. The parallel link unit 510 has a control unit 512 and a link unit 514. The gripper unit 520 has a control unit 522 and a hand unit 524. The hand portion 524 may be a gripper that holds the press-molded product 800 by magnetic attraction.

The tracking image pickup unit 200 images a predetermined tracking area of the belt conveyor 700 at predetermined intervals. The width of the tracking region may be the same as the width of the belt of the belt conveyor 700 (direction orthogonal to the transport direction). The length (conveyance direction) of the tracking region is appropriately set so that all the press-molded products 800 transported on the belt conveyor 700 can be imaged based on the imaging interval and the moving speed of the belt of the belt conveyor 700. It's okay.

The tracking image pickup unit 200 may take an image of the press-molded product 800 illuminated by the illumination for imaging. The tracking image pickup unit 200 can capture an image without a shadow on the surface of the press-molded product 800 by illuminating the press-molded product 800 with the illumination for imaging. The image of the press-molded product 800 captured by the tracking image pickup unit 200 is transmitted to the tracking unit 130 via the main control unit 110. The tracking unit 130 specifies the position of the press-molded product 800 when the tracking image pickup unit 200 images the press-molded product 800. The tracking unit 130 detects the relative position of the press-molded article 800 with respect to a predetermined position in the tracking area. For example, the tracking unit 130 extracts the contour of the press-molded product 800 by edge processing the image, and based on the extracted contour, the press-molded product 800 is based on a predetermined position in the tracking region. The coordinate values of each axis (x-axis, y-axis, and z-axis) and the coordinate values in the rotation direction of each axis are specified as coordinate information indicating the position of the press-molded product 800. The tracking unit 130 transmits coordinate information indicating the position of the press-molded product 800 and the measured value at the time of shooting of the tracking imaging unit 200 by the encoder that measures the movement amount of the belt conveyor 700 via the main control unit 110. Send to 310.

The control unit 312 of the parallel link unit 310 determines the position of the press-molded product 800 in the measurement region measured by the displacement measurement unit 320 based on the coordinate information and the measured value and the amount of movement of the press-molded product 800 by the belt conveyor 700. Specify the coordinate information indicating. The control unit 312 may specify the coordinate value of each axis of the press-molded product 800 and the coordinate value in the rotation direction of each axis as the coordinate information with reference to a predetermined position in the measurement area.

Further, the control unit 312 obtains the coordinate information of the press-molded product 800 in the measurement region and the predetermined position information indicating the relative position of the portion to be the necking inspection with respect to the reference point of the press-molded product 800. Based on this, the coordinate values of each axis of the part to be the target of the necking inspection of the press-molded product 800 and the coordinate values in the rotation direction of each axis based on the predetermined position in the measurement area are obtained by the necking inspection. Specify as the coordinate information of the target part. The control unit 312 operates the link unit 314 based on the coordinate information of the part to be the target of the necking inspection of the press-molded product 800 based on the predetermined position in the measurement area, and sets the link unit 314 as the target of the necking inspection. The laser displacement meter 324 may be aligned with the measurement position of the portion.

The laser displacement meter 324 may be arranged only on one side of the press-molded product 800 to be inspected for necking in the thickness direction. The control unit 322 causes the laser displacement meter 324 to irradiate the measurement position of the portion to be inspected for the necking inspection of the press-molded product 800 with the laser beam. The control unit 312 operates the link unit 314 to move the laser displacement meter 324 in the longitudinal direction of the portion to be inspected for necking. The laser displacement meter 324 may scan the line laser beam extending in the lateral direction different from the longitudinal direction of the portion to be inspected for necking along the longitudinal direction. The laser displacement meter 324 receives the reflected light from a plurality of measurement positions of the portion to be inspected for necking. The control unit 322 transmits a plurality of waveform data showing a two-dimensional surface waveform including a plurality of measurement positions measured by the laser displacement meter 324 to the main control unit 110.

The main control unit 110 transmits the received waveform data to the necking inspection unit 120. The displacement acquisition unit 122 of the necking inspection unit 120 acquires a plurality of waveforms indicating a two-dimensional surface shape including a plurality of measurement positions. The derivation unit 124 derives the second-order differential waveform of each waveform by second-order differentiation of each of the acquired plurality of waveforms. The necking determination unit 126 is subject to the necking inspection for necking in which the plate thickness is locally reduced or cracks are locally generated due to local elongation deformation based on the second-order differential waveform of each waveform. Determine if it occurs at the site.

The necking determination unit 126 determines that the necking is the target of the necking inspection based on whether or not the second-order differential waveform of each acquired waveform satisfies a predetermined necking occurrence condition indicating that the occurrence of necking is high. It may be determined whether or not it has occurred. The necking determination unit 126 generates necking at a portion to be inspected for necking based on whether or not the second-order differential waveform of each acquired waveform satisfies a predetermined waveform pattern indicating that the occurrence of necking is high. It may be determined whether or not it is done. The predetermined waveform pattern may be sequentially updated by machine learning the waveform pattern in which necking actually occurs. The necking determination unit 126 generates necking at a portion to be inspected for necking based on whether or not the amplitude of the second-order differential waveform of each acquired waveform is equal to or higher than a predetermined amplitude indicating that the occurrence of necking is high. It may be determined whether or not it is done. The necking determination unit 126 may determine whether or not necking occurs at a portion to be inspected for necking based on the maximum point and the minimum point on the second-order differential waveform of each acquired waveform. The necking determination unit 126 determines that the necking is the target of the necking inspection based on the difference between the maximum point and the minimum point that are adjacent to each other on the second-order differential waveform of each acquired waveform and include a zero point in between. It may be determined whether or not it has occurred. When the necking determination unit 126 is adjacent to each other on the second-order differential waveform and the difference between the maximum point including the zero point and the minimum point is equal to or more than a predetermined threshold value, the second-order differential waveform is predetermined. It may be determined that the specified necking occurrence condition is satisfied. The necking determination unit 126 is adjacent to each other on the second derivative waveform of the first waveform among the plurality of waveforms, and the difference between the maximum point and the minimum point including the zero point between them, and the second waveform among the plurality of waveforms. If the difference between the maximum point including the zero point and the minimum point on the second-order differential waveform is equal to or greater than a predetermined threshold, necking occurs at the site to be inspected for necking. It may be determined that it is. The necking determination unit 126 performs a necking inspection when, among a plurality of second-order differential waveforms at a plurality of measurement positions, a predetermined number or more of the second-order differential waveforms continuously satisfy a predetermined necking occurrence condition. It may be determined that necking has occurred in the target portion.

The appearance image pickup unit 400 takes an image of the press-molded product 800 and transmits the image data of the imaged press-molded product 800 to the main control unit 110. The main control unit 110 transmits the received image data to the image acquisition unit 142 of the visual inspection unit 140. The appearance determination unit 144 may determine whether or not defective parts such as scratches, dents, distortions, and stains are present in the press-molded product 800 based on the received image data of the press-molded product 800. The appearance determination unit 144 matches the predetermined good image of the press-molded product 800 with the received image of the press-molded product 800, and the similarity of the press-molded products in each image is predetermined. If it is equal to or less than the threshold value, it may be determined that the press-molded product 800 in the image has a defective portion. The appearance determination unit 144 matches the predetermined shape and color (for example, white and black) pattern of the defective portion with the received image of the press-molded product 800, so that the press-molded product 800 in the image is matched. It may be determined whether or not there is a defective part in. The appearance determination unit 144 transmits the determination result to the main control unit 110. Based on the determination result, the main control unit 110 transmits to the alignment processing unit 500 instruction information to move the press-molded product 800 to the non-defective product container 900 or the defective product container 902.

The control unit 512 of the alignment processing unit 500 operates the link unit 514 according to the instruction information received from the main control unit 110 to bring the hand unit 524 into contact with the press-molded product 800. The control unit 522 of the gripper unit 520 operates the hand unit 524 to adsorb the press-molded product 800. The control unit 512 operates the link unit 514 to house the press-molded product 800, which is determined to have no defective portion, that is, a non-defective product, in the non-defective container 900. The control unit 512 operates the link unit 514 to accommodate the press-molded product 800, which has a defective portion, that is, is determined to be a defective product, in the defective product container 902.

FIG. 4A is a diagram showing an example of a waveform measured at an arbitrary position of a portion to be inspected for necking, a first-order differential waveform obtained by first-order differentiating the measured waveform, and a second-order differential waveform obtained by second-order differentiation. The graph of the measurement data shown in FIG. 4A represents a cross-sectional shape at an arbitrary position of a portion to be inspected for necking, that is, a two-dimensional surface shape. By moving the laser displacement meter 324 in the longitudinal direction of the portion to be inspected for necking, two-dimensional surface shapes at continuous positions of the portion to be inspected for necking can be obtained one after another.

When the necking determination unit 126 is adjacent to each other on the second-order differential waveform of the acquired waveform and the difference between the maximum point including the zero point and the minimum point is equal to or more than a predetermined threshold value, the necking determination unit 126 is subject to the necking inspection. It may be determined that necking has occurred in the portion to be. In the second-order differentiated graph shown in FIG. 4A, there is no inflection point that intersects the 0 point. Therefore, in the second-order differentiated graph shown in FIG. 4A, the difference between the maximum point and the minimum point, which are adjacent to each other on the second-order differential waveform of the waveform and include a zero point in between, is equal to or more than a predetermined threshold value. There is no waveform to indicate that. In this case, the necking determination unit 126 may determine that necking has not occurred at the portion to be inspected for necking.

FIG. 4B is a diagram showing an example of a waveform measured at an arbitrary position of a portion to be inspected for necking, a first-order differential waveform obtained by first-order differentiating the measured waveform, and a second-order differential waveform obtained by second-order differentiation. In the second-order differentiated graph shown in FIG. 4B, there is an inflection point surrounded by the necking portion 1000, which is once greatly lowered before and after crossing the 0 point and then greatly increased. When the difference between the maximum point and the minimum point including the zero point is equal to or more than a predetermined threshold value on the waveform existing in the range surrounded by the necking unit 1000, the necking determination unit 126 is adjacent to each other. , It may be determined that necking has occurred at the site to be inspected for necking.

Other methods can be mentioned as a method of necking inspection. In this method, first, the waveform of the measured data is enlarged. Next, the radius of curvature of the curved part of the waveform is calculated. Then, by determining whether or not the calculated radius of curvature is larger than the threshold value, it is determined whether or not necking has occurred. According to this method, the threshold value of the radius of curvature must be set according to the shape of the part to be pressed. It is troublesome to set a threshold value of the radius of curvature for each shape of the part to be pressed. According to the method for determining necking in one embodiment, a local change, that is, necking can be found by performing a second derivative and graphing the variable curvature. According to the method for determining necking in one embodiment, the presence or absence of necking can be determined from the two-dimensional surface shape of the portion to be inspected for necking without using two laser displacement meters 324.

FIG. 5 is a flowchart showing an example of a procedure for determining the necking of the press-molded product 800. The tracking unit 130 specifies the position of the press-molded product 800 by the tracking process (S100). The tracking unit 130 may analyze the image of the press-molded product 800 imaged by the tracking image pickup unit 200 to specify the position of the press-molded product 800. The tracking unit 130 uses image recognition processing to obtain coordinate values indicating the coordinate values of each axis of the press-molded product 800 and the coordinate values in the rotational direction of each axis based on a predetermined position in the tracking area. It may be specified as the position of the press-molded product 800.

The control unit 312 of the parallel link unit 310 specifies a portion to be inspected for necking (S102). The control unit 312 determines the press-molded product 800 in the measurement area based on the coordinate information of the press-molded product 800 and the amount of movement of the press-molded product 800 from the tracking area of the tracking image pickup unit 200 to the measurement area of the displacement measurement unit 320. Coordinate information indicating the position of may be specified. The control unit 312 may specify the coordinate value of each axis of the press-molded product 800 and the coordinate value in the rotation direction of each axis as the coordinate information with reference to a predetermined position in the measurement area. Further, the control unit 312 obtains the coordinate information of the press-molded product 800 in the measurement region and the predetermined position information indicating the relative position of the portion to be the necking inspection with respect to the reference point of the press-molded product 800. Based on this, the coordinate values of each axis of the part to be the target of the necking inspection of the press-molded product 800 and the coordinate values in the rotation direction of each axis based on the predetermined position in the measurement area are obtained by the necking inspection. It may be specified as the coordinate information of the target part.

The displacement acquisition unit 122 acquires a plurality of waveforms indicating a two-dimensional surface shape including each of the plurality of positions in the site to be inspected for necking, which is measured by the laser displacement meter 324 (S104). The derivation unit 124 derives the second-order differential waveforms of the plurality of waveforms by second-order differentiation of each of the plurality of waveforms (S106).

The necking determination unit 126 determines whether or not each of the plurality of second-order differential waveforms satisfies the necking occurrence condition (S108). The necking determination unit 126 is subject to the necking inspection for necking in which the plate thickness is locally reduced or cracks are locally generated due to local elongation deformation based on the second-order differential waveform of each waveform. It may be determined whether or not it occurs at the site. The necking determination unit 126 may determine whether or not necking occurs at a portion to be inspected for necking based on the maximum point and the minimum point on the second-order differential waveform of each acquired waveform. The necking determination unit 126 determines that the necking is the target of the necking inspection based on the difference between the maximum point and the minimum point that are adjacent to each other on the second-order differential waveform of each acquired waveform and include a zero point in between. It may be determined whether or not it has occurred.

The necking determination unit 126 is adjacent to each other on the second derivative waveform of the first waveform among the plurality of waveforms, and the difference between the maximum point and the minimum point including the zero point between them, and the second waveform among the plurality of waveforms. If the difference between the maximum point including the zero point and the minimum point on the second-order differential waveform is equal to or greater than a predetermined threshold, necking occurs at the site to be inspected for necking. It may be determined that it is (S110). In the necking determination unit 126, among a plurality of second-order differential waveforms, a predetermined number or more of continuous second-order differential waveforms are adjacent to each other, and the difference between the maximum point including the zero point and the minimum point is different. When the conditions for generating necking, which are equal to or higher than a predetermined threshold value, are satisfied, it may be determined that necking has occurred in the portion to be inspected for necking. The necking determination unit 126 is adjacent to each other on the second derivative waveform of the first waveform among the plurality of waveforms, and the difference between the maximum point and the minimum point including the zero point between them, and the second waveform among the plurality of waveforms. If the difference between the maximum point including the zero point and the minimum point on the second-order differential waveform is not equal to or greater than a predetermined threshold, necking has occurred at the site to be inspected for necking. It may be determined that there is no such thing (S112). In the necking determination unit 126, among a plurality of second-order differential waveforms, a predetermined number or more of continuous second-order differential waveforms are adjacent to each other, and the difference between the maximum point including the zero point and the minimum point is different. If the conditions for generating necking that are equal to or higher than the predetermined thresholds are not satisfied, it may be determined that necking has not occurred at the site to be inspected for necking.

The visual inspection unit 140 inspects the appearance of the press-molded product 800 imaged by the camera (S114). The image acquisition unit 142 may acquire an image of the press-molded product 800 imaged by the appearance image pickup unit 400. Based on the image data of the press-molded product 800 acquired by the image acquisition unit 142, the appearance determination unit 144 determines whether or not the press-molded product 800 has defective parts such as scratches, dents, distortions, and stains. You may judge.

The main control unit 110 may determine whether or not both the conditions for generating necking and the conditions for visual inspection are satisfied (S116). When the press-molded product 800 has no necking and no defective portion exists, the main control unit 110 determines that the press-molded product 800 is a non-defective product (S118). When the press-molded product 800 has necking or a defective portion exists, the main control unit 110 determines that the press-molded product 800 is a defective product (S120). The main control unit 110 moves the press-molded product 800 to the alignment processing unit 500 to the non-defective product container 900 or the defective product container 902 according to the determination result, packs the non-defective product, and ends the processing.

According to the method for determining necking in one embodiment, it is possible to inspect whether or not necking has occurred from one side of the press-molded product, so that the equipment for necking inspection can be made compact and the cost of the equipment can be increased. Can be reduced. Even without using two laser displacement meters 324, it is possible to determine the presence or absence of necking from the two-dimensional surface shape of the portion to be inspected for necking, and it becomes easy to secure the installation space for the laser displacement meter 324.

According to the method for determining necking in one embodiment, it is necessary to adjust the parameters of the determination criteria for each shape of the press-molded product to be inspected, as in the method for determining necking based on the radius of curvature of the two-dimensional surface shape. There is no. Therefore, it is possible to reduce the burden of determining the necking of the press-molded product.

In the above embodiment, an example in which the displacement acquisition unit 122 acquires a waveform showing the two-dimensional surface shape of the portion to be the necking inspection measured by the laser displacement meter 324 has been described. However, if the displacement acquisition unit 122 can acquire a waveform indicating the two-dimensional surface shape of the portion to be inspected by the necking inspection, the displacement acquisition unit 122 obtains a waveform indicating the two-dimensional surface shape from the measurement results from a measuring instrument other than the laser displacement meter. You may get it. The displacement acquisition unit 122 may acquire a waveform showing a two-dimensional surface shape from the measurement results of a white interferometer using a white light source or an optical comb distance meter using optical comb interference.

Further, the necking determination unit 126 has described an example of determining the necking of the press-molded product 800 based on whether or not the second-order differential waveform satisfies a predetermined necking generation condition. However, the necking determination unit 126 may determine whether or not necking has occurred in a predetermined portion based on the amount of change in the waveform indicating the two-dimensional surface shape. The necking determination unit 126 may determine whether or not necking has occurred at a predetermined portion based on the amount of change per unit distance of the waveform showing the two-dimensional surface shape. The necking determination unit 126 determines, for example, a predetermined change pattern in which the difference per unit distance of the waveform showing the two-dimensional surface shape or the difference per unit distance of the first-order differential waveform of the waveform showing the two-dimensional surface shape. The necking of the press-molded product 800 may be determined based on whether or not it is satisfied. For example, when necking occurs due to a crack, the amplitude becomes large even in the first derivative waveform of the waveform showing the two-dimensional surface shape. Therefore, the necking determination unit 126 can easily determine the presence or absence of necking due to a crack based on the first-order differential waveform of the waveform showing the two-dimensional surface shape.

FIG. 6 shows an example of a computer 1200 in which a plurality of aspects of the present invention may be embodied in whole or in part. The program installed on the computer 1200 can cause the computer 1200 to function as an operation associated with the device according to an embodiment of the present invention or as one or more "parts" of the device. Alternatively, the program may cause the computer 1200 to perform the operation or the one or more "parts". The program may cause the computer 1200 to perform a process according to an embodiment of the present invention or a step of the process. Such a program may be run by the CPU 1212 to cause the computer 1200 to perform certain operations associated with some or all of the blocks of the flowcharts and block diagrams described herein.

The computer 1200 according to this embodiment includes a CPU 1212 and a RAM 1214, which are connected to each other by a host controller 1210. The computer 1200 also includes a communication interface 1222, an input / output unit, which are connected to the host controller 1210 via an input / output controller 1220. The computer 1200 also includes a ROM 1230. The CPU 1212 operates according to a program stored in the ROM 1230 and the RAM 1214, thereby controlling each unit.

The communication interface 1222 communicates with other electronic devices via the network. A hard disk drive may store programs and data used by the CPU 1212 in the computer 1200. The ROM 1230 stores in it a boot program or the like executed by the computer 1200 at the time of activation and / or a program depending on the hardware of the computer 1200. The program is provided via a computer-readable recording medium such as a CR-ROM, USB memory or IC card or a network. The program is installed in RAM 1214, which is also an example of a computer-readable recording medium, or ROM 1230, and is executed by the CPU 1212. The information processing described in these programs is read by the computer 1200 and provides a link between the program and the various types of hardware resources described above. The device or method may be configured to implement the operation or processing of information in accordance with the use of the computer 1200.

For example, when communication is executed between the computer 1200 and an external device, the CPU 1212 executes a communication program loaded in the RAM 1214, and performs communication processing with respect to the communication interface 1222 based on the processing described in the communication program. You may order. Under the control of the CPU 1212, the communication interface 1222 reads the transmission data stored in the transmission buffer area provided in the RAM 1214 or a recording medium such as a USB memory, and transmits the read transmission data to the network, or The received data received from the network is written to the reception buffer area or the like provided on the recording medium.

Further, the CPU 1212 makes the RAM 1214 read all or necessary parts of a file or a database stored in an external recording medium such as a USB memory, and executes various types of processing on the data on the RAM 1214. good. The CPU 1212 may then write back the processed data to an external recording medium.

Various types of information such as various types of programs, data, tables, and databases may be stored in recording media and processed. The CPU 1212 describes various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, and information retrieval described in various parts of the present disclosure with respect to the data read from the RAM 1214. Various types of processing may be performed, including / replacement, etc., and the results are written back to the RAM 1214. Further, the CPU 1212 may search for information in a file, database, or the like in the recording medium. For example, when a plurality of entries each having an attribute value of the first attribute associated with the attribute value of the second attribute are stored in the recording medium, the CPU 1212 specifies the attribute value of the first attribute. Search for an entry that matches the condition from the plurality of entries, read the attribute value of the second attribute stored in the entry, and associate it with the first attribute that satisfies the predetermined condition. The attribute value of the second attribute obtained may be acquired.

The program or software module described above may be stored on a computer 1200 or in a computer readable storage medium near the computer 1200. Also, a recording medium such as a hard disk or RAM provided in a dedicated communication network or a server system connected to the Internet can be used as a computer readable storage medium, thereby allowing the program to be transferred to the computer 1200 over the network. offer.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the claims that embodiments with such modifications or improvements may also be included in the technical scope of the invention.
The execution order of each process such as operation, procedure, step, and step in the device, system, program, and method shown in the claims, the specification, and the drawing is particularly "before" and "prior to". It should be noted that it can be realized in any order unless the output of the previous process is used in the subsequent process. Even if the claims, the description, and the operation flow in the drawings are explained using "first", "next", etc. for convenience, it means that it is essential to carry out in this order. is not.

1 Inspection system 100 Control device 110 Main control unit 120 Necking inspection unit 122 Displacement acquisition unit 124 Derivation unit 126 Necking judgment unit 130 Tracking unit 140 Appearance inspection unit 142 Image acquisition unit 144 Appearance judgment unit 200 Tracking image unit 300 Necking measurement unit 310 Parallel Link unit 312 Control unit 314 Link unit 320 Displacement measurement unit 322 Control unit 324 Laser displacement meter 325 Line laser light 400 Appearance imaging unit 500 Alignment processing unit 510 Parallel link unit 512 Control unit 514 Link unit 520 Gripper unit 522 Control unit 524 Hand unit 600 Network 700 Belt conveyor 800 Press molded product 810 Displacement 900 Good product container 902 Defective product container 1000 Necking part 1200 Computer 1210 Host controller 1212 CPU
1214 RAM
1220 Input / Output Controller 1222 Communication Interface 1230 ROM

Claims (15)

The stage of acquiring the first waveform showing the two-dimensional surface shape including the first position of the predetermined portion of the press-molded product, and
The stage of deriving the amount of change in the first waveform and
A method for determining necking of a press-molded product, comprising a step of determining whether or not necking occurs in the predetermined portion based on the amount of change in the first waveform. The method for determining necking of a press-molded product according to claim 1, wherein in the determination step, when the amount of change satisfies a predetermined change pattern, it is determined that necking occurs at the predetermined portion. .. In the determination step, whether or not the necking occurs in the predetermined portion based on whether or not the difference per unit distance of the first waveform satisfies the predetermined change pattern. The necking determination method for a press-molded product according to claim 2, which comprises a step of determining. In the determination step, the necking occurs at the predetermined portion based on whether or not the difference per unit distance of the first-order differential waveform of the first waveform satisfies a predetermined change pattern. The necking determination method for a press-molded product according to claim 2, which comprises a step of determining whether or not the product is. The necking determination method for a press-molded product according to claim 1 or 2, wherein the derivation step includes a step of deriving the change amount by differentiating the first waveform. The derivation step includes a step of deriving the second-order differential waveform of the first waveform as the change amount by second-order differentiation of the first waveform.
The press-molded product according to claim 5, wherein the determination step includes a step of determining whether or not necking occurs in the predetermined portion based on the second-order differential waveform of the first waveform. Necking judgment method. The determination step includes a step of determining whether or not the necking occurs at the predetermined portion based on the maximum point and the minimum point on the second-order differential waveform of the first waveform. The method for determining necking of a press-molded product according to claim 6. The determination step is based on the difference between the maximum point and the minimum point that are adjacent to each other on the second-order differential waveform of the first waveform and include a zero point in between, and the necking is performed at the predetermined portion. The necking determination method for a press-molded product according to claim 7, which comprises a step of determining whether or not the occurrence has occurred. The acquisition step is the predetermined portion measured by a laser displacement meter that irradiates a predetermined portion of the press-molded product with a laser beam and receives the reflected light from the predetermined portion. The method for determining necking of a press-molded product according to any one of claims 1 to 8, further comprising the step of acquiring the first waveform showing the two-dimensional surface shape including the first position. The laser displacement meter scans a line laser beam extending in a short direction different from the longitudinal direction of the predetermined portion along the longitudinal direction.
The acquisition step acquires a second waveform indicating a two-dimensional surface shape including a second position different from the first position along the longitudinal direction of the predetermined portion measured by the laser displacement meter. Including stages
The derivation step includes a step of deriving the second derivative waveform of the second waveform by second-order differentiating the second waveform.
The determination step is a step of determining whether or not the necking occurs in the predetermined portion based on the second-order differential waveform of the first waveform and the second-order differential waveform of the second waveform. The method for determining necking of a press-molded product according to claim 9, which includes. The determination step is adjacent to each other on the second-order differential waveform of the first waveform, the difference between the maximum point and the minimum point including a zero point in between, and each other on the second-order differential waveform of the second waveform. When the difference between the maximum point and the minimum point, which are adjacent to each other and include a zero point, is equal to or larger than a predetermined threshold value, the step of determining that the necking has occurred in the predetermined portion is included. The method for determining necking of a press-molded product according to claim 10. The acquisition step is any one of claims 1 to 8, including a step of acquiring the first waveform from the measurement result of a white interferometer using a white light source or an optical comb distance meter using optical comb interference. The method for determining necking of a press-molded product according to. In the determination step, necking occurs at the predetermined portion based on whether or not the second-order differential waveform of the first waveform satisfies a predetermined waveform pattern indicating that the occurrence of necking is high. Including the step of determining whether or not
The necking determination method for a press-molded product according to any one of claims 1 to 12, wherein the predetermined waveform pattern is sequentially updated by machine learning the waveform pattern in which necking actually occurs. An acquisition unit that acquires a first waveform indicating a two-dimensional surface shape including a first position of a predetermined portion of a press-molded product, and an acquisition unit.
A derivation unit that derives the amount of change in the first waveform, and
A necking determination device for a press-molded product, comprising a determination unit for determining whether or not necking has occurred in the predetermined portion based on the amount of change in the first waveform. A program for causing a computer to execute the necking determination method for a press-molded article according to any one of claims 1 to 13.

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