Marking reading device for metal molded article, management system for metal molded article, and marking reading method for metal molded article

Abstract

[Problem] To provide a marking reading device, a management system, and a marking reading method which it possible to improve the rate of reading of a marking on a metal molded article. [Solution] A reading unit 50 comprises: a first illumination device 51a which emits light to a can bottom part 6a; a reader which images a marking M in synchronization with the timing of emission by the first illumination device 51a; a second illumination device 52a which emits light to the can bottom part 6a from a direction that differs from that of the first illumination device 51a in a view of the surface of the can bottom part 6a from the normal direction; and a reader which images a marking in synchronization with the timing of emission by the second illumination device 52a.

Description

Marking reading device for metal molded products, management system for metal molded products, and method for reading marking for metal molded products

[0001] The present invention relates to a marking reading device, a management system, and a marking reading method for metal formed products manufactured from rolled material.

[0002] Conventionally, there has been a device that captures images of markings on the surface of rolled metal material by illuminating the surface of the rolled material from a direction parallel to the rolling direction (see, for example, Patent Document 1). However, it is extremely difficult to store, transport, or otherwise process metal molded products formed from rolled material so that the rolling direction is consistent. For this reason, conventional devices have not been able to stably capture clear images of metal molded products.

[0003] Japanese Patent Application Laid-Open No. 2000-123111

[0004] An object of the present invention is to provide a marking reading device, a management system, and a marking reading method that can clearly capture an image of a marking on a metal formed product manufactured from rolled material.

[0005] One aspect of the present invention is a marking reading device for a marking shown on a marking formation portion on the surface of a metal molded product manufactured, for example, from a rolled metal plate, characterized in that the marking reading device for a metal molded product comprises: a first illumination unit that irradiates light onto the marking formation portion; a first imaging unit that captures an image of the marking in synchronization with the irradiation timing of the first illumination unit; a second illumination unit that irradiates light onto the marking formation portion from a direction different from that of the first illumination unit while viewing the marking formation portion from a normal direction; and a second imaging unit that captures an image of the marking in synchronization with the irradiation timing of the second illumination unit. Another aspect of the present invention is a marking reading method for a marking shown on a marking formation portion on the surface of a metal molded product manufactured, for example, from a rolled metal plate, the method comprising: a first illumination step of irradiating the marking formation portion with light; a first imaging step of imaging the marking in synchronization with the irradiation timing of the first illumination step; a second illumination step of irradiating the marking formation portion with light from a direction different from that of the first illumination step while viewing the marking formation portion from a normal direction; and a second imaging step of imaging the marking in synchronization with the irradiation timing of the second illumination step.

[0006] 5(B) is a diagram illustrating the configuration of a management system 1 for cans 6 according to an embodiment. FIG. 5(C) is a diagram illustrating information stored in a process history storage unit 25b according to an embodiment. FIG. 5(D) is a diagram illustrating how light L30 from an illumination device 30 according to an embodiment is reflected on the surface of a rolled metal material 5. FIG. 5(E) is a diagram illustrating verification results in which a captured image of a can bottom 6a according to an embodiment changes depending on the irradiation angle θ30. FIG. 5(F) is a diagram illustrating a reading unit 50 according to an embodiment. FIG. 5(C) is a diagram illustrating the focusing of light by a focusing lens 53 according to an embodiment and the reflection of light on a rim 6b of the can bottom 6a, and is an enlarged view of a portion of FIG. 5(C). FIG. 5(D) is a diagram illustrating an example in which a reading unit 60 according to an embodiment is installed as a reading unit 24b near a conveying wheel 24d of an inspection device 24. FIG. 5(E) is a diagram illustrating an example in which a reading unit 60 according to an embodiment is installed as a reading unit 24b near a conveying wheel 24d of an inspection device 24. FIG. 5(F) is a diagram illustrating an example in which a reading unit 70 according to an embodiment is attached to a mandrel wheel 23d of a printing device 23 as a reading unit 23b. FIG. 2 is an enlarged view showing the configuration of a reading unit 70 and its surroundings according to the embodiment.

[0007] (Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating the configuration of a management system 1 for cans 6 according to an embodiment. FIG. 2 is a diagram illustrating information stored in a process history storage unit 25b according to an embodiment. As shown in FIG. 1, the management system 1 is a system for manufacturing cans 6 (formed metal products, formed metal cans) from rolled metal (aluminum, steel, etc.) and a system for managing the process history of the manufactured cans 6. The cans 6 manufactured by the management system 1 are empty cans. In the embodiment, a two-piece can is used as an example. Note that in the embodiment, the can 6 is not limited to a finished product, but also includes an intermediate product to be processed into the can 6 (e.g., an intermediate product after a cupping press process). The can 6 has a rim 6b on the can bottom 6a (see FIG. 5(C) , etc.). The rim 6b is a protrusion provided within a circular ring-shaped area on the periphery of the can bottom 6a when viewed from the can axial direction. The rim 6b protrudes downward from this circular ring-shaped area in the can axial direction. The management system 1 includes a manufacturing system 10 (can manufacturing system) and a management device 25 .

[0008] (Manufacturing System 10) The manufacturing system 10 is a system installed on a production line in a manufacturing plant for cans 6. The manufacturing system 10 includes a cupping press device 21, a can body processing device 22, a printing device 23, and an inspection device 24. The cupping press device 21, the can body processing device 22, the printing device 23, and the inspection device 24 can communicate with a management device 25 via a communication network 2 such as a LAN. Note that in a configuration in which the management device 25 is installed in a management facility outside the manufacturing plant, in cloud computing, or the like, the communication network 2 may include a line such as the Internet.

[0009] In the embodiments, a computer refers to a device including an electronic calculator equipped with a storage device, a control device, an arithmetic device, etc. The cupping press device 21, the can body processing device 22, the printing device 23, the inspection device 24, the management device 25, and the reading units 50, 60, and 70 each include a storage unit, a control unit, etc., and are included in the concept of a computer. Furthermore, each device is not limited to being configured by a single electronic computer, but may be configured by multiple electronic computers as needed. The storage unit is a storage device such as a hard disk or semiconductor memory element for storing programs, information, etc. necessary for the operation of each device. The control unit is a device for performing arithmetic processing necessary for the operation of each device and for overall control of each device. The control unit is composed of, for example, a CPU (central processing unit). The control unit realizes various functions of the embodiments by appropriately reading and executing various programs stored in the storage unit.

[0010] The cupping press device 21, can body processing device 22, printing device 23, and inspection device 24 are arranged in this order from upstream to downstream of the production line. The cupping press device 21, can body processing device 22, printing device 23, and inspection device 24 are equipped with reading units 21b, 22b, 23b, and 24b, and control units 21i, 22i, 23i, and 24i, respectively.

[0011] As will be described later, reading units 21b, 22b, 23b, and 24b are devices that read markings M on can bottoms 6a in each process. If processing, etc. is performed in multiple lanes in each process, a reading unit may be provided for each lane, or one reading unit may be configured to read markings M on cans 6 that are processed, etc. in multiple lanes.

[0012] In the latter case, one reading unit may read the marking M on a can 6 upstream of a lane and then determine which of multiple lanes the can 6 has been moved to. For example, in a can body processing process where multiple lanes each have a can body processing device 22, one reading unit may be located upstream of the lane. Furthermore, communication may be established between this one reading unit and a sorting device that sorts the cans 6 to the lanes. The reading unit may then obtain information from the sorting device regarding which lane the can 6 whose marking M has been read has been transported to.

[0013] The cupping press device 21 is a device that performs the cupping process. Although not shown, the cupping press device 21 is equipped with a press machine or the like and performs punching, drawing, and the like. In punching, the rolled material 5 pulled out from the roll is punched into a disk shape using a punching die. In drawing, the rolled material 5 punched into a disk shape is drawn into a cup shape using a mold (die, punch, etc.). In drawing, the can bottom 6 a is formed into a dome shape, a flat shape, or the like depending on the type of can 6. In the embodiment, the drawing in the cupping process is also referred to as cupping, and the cup-shaped member machined from the rolled material 5 is also referred to as a metal cup, as appropriate.

[0014] The cupping press device 21 includes a marking device 21a. The marking device 21a prints or imprints a marking M in an area that will form the can bottom 6a of the can 6. The marking device 21a is, for example, an inkjet printer, a laser marker, or the like. The marking device 21a may print or imprint the marking M in an area of ​​the rolled material 5 that will be processed into the can bottom 6a after punching but before cup processing, or may print or imprint the marking M on the can bottom 6a of a metal cup produced by cup processing the rolled material 5. The marking M is a display including can identification information that can identify the can 6. The can identification information may be, for example, a sequential number, a symbol, or the like. The marking M is a display that encodes the can identification information. In the embodiment, an example is described in which the marking M is a two-dimensional code having information that encodes information including the can identification information. However, the marking M is not limited to this. For example, the marking M may be a one-dimensional code or the can identification information itself (numbers, symbols, etc.). The can identification information may be issued by the marking device 21a. Alternatively, the management device 25 may issue the can identification information, and the marking device 21a may acquire the can identification information.

[0015] The can body processing device 22 is a device that performs a can body processing process (also called a body maker process). Although not shown, the can body processing device 22 includes a processing device that performs an ironing process on a metal cup. In the ironing process, an ironing die is used to thinly stretch the can body in the can axial direction.

[0016] The printing device 23 is a device that performs a printing process and includes a blanket 23f that transfers ink to the can body, a burnish roller 23h that applies varnish, and the like (see FIG. 9).

[0017] The inspection device 24 is a device that performs the inspection process. The inspection device 24 is equipped with a camera that captures images of the cans 6. The inspection device 24 can determine the quality of the cans 6 (for example, visual inspection, dimensional inspection, etc.) by analyzing the captured images. Based on the quality results, the inspection device 24 determines whether the visual quality of the cans 6 is OK (pass) or NG (fail).

[0018] The control units 21i, 22i, 23i, 24i of each of the above devices associate the can identification information obtained by decoding the marking M read by the inspection device 24 with the manufacturing information of the can 6 as can identification information-manufacturing information, and output this to the management device 25. The manufacturing information is information about the manufacturing equipment of each device (see FIG. 2). The manufacturing information of each device is the following information: Cupping press device 21: punching die model numbers 1 to 5 Can body processing device 22: lane numbers 1 to 5 Printing device 23: blanket numbers 1 to 5 Inspection device 24: inspection result NG, OK

[0019] The manufacturing information is not limited to the above information, but may be, for example, information on the processing date and time, processing conditions of each device (e.g., press pressure, feed speed during printing, temperature of various processing liquids, etc.), or may include two or more pieces of information.

[0020] (Management Device 25) The management device 25 is a device that manages the manufacturing history of cans 6. The management device 25 is, for example, a device such as a server or a personal computer. The management device 25 includes a memory unit 25a and a control unit 25i. The memory unit 25a includes a process history memory unit 25b. As shown in FIG. 2, the process history memory unit 25b stores can identification information and manufacturing information in association with each other. The control unit 25i performs processing, such as storing and managing the manufacturing history in the process history memory unit 25b, based on the can identification information and manufacturing information output from each device. The manufacturing history is a history of manufacturing information during the manufacturing process of the can 6. For example, a can 6 bearing a marking M having "can identification information = 0001" has the marking M read by each of the reading units of the cupping press device 21, the can body processing device 22, the printing device 23, and the inspection device 24. Each device then outputs the can identification information and manufacturing information having "can identification information = 0001" to the management device 25. Based on the can identification information-manufacturing information transmitted from each device, the control unit 25i of the management device 25 associates "can identification information=0001" with the manufacturing information of each device and stores the information in sequence in the process history storage unit 25b. This allows the management device 25 to store and manage the manufacturing history of cans 6 bearing the marking M having "can identification information=0001."

[0021] Here, the order of conveyance of the multiple cans 6 in the manufacturing process is irregular. For example, even if the can 6 with "can identification information = 0001" is processed before the can 6 with "can identification information = 0002" in the cupping press process, the can 6 with "can identification information = 0002" may be processed before the can 6 with "can identification information = 0001" in the can body processing process. For this reason, the manufacturing history of the cans 6 cannot be managed based on the manufacturing order.

[0022] In contrast, in the embodiment, the manufacturing history can be stored and managed based on the can identification information and manufacturing information output from each device. Therefore, the manufacturing information of each can 6 can be tracked based on the can identification information. This allows the management system 1 to manage manufacturing information of cans 6 on the manufacturing line, cans 6 after shipment, etc. based on the can identification information of the can 6.

[0023] [Relationship between Illumination Angle and Captured Image] Here, the relationship between the illumination angle θ30 of the illumination device 30 that irradiates the can bottom with illumination light when reading the marking M and the captured image of the can bottom 6a will be described. Figure 3 is a diagram illustrating how light L30 from the illumination device 30 of the embodiment is reflected on the surface of the rolled metal material 5. In the embodiment, the angle formed by the optical axis of the illumination light from the illumination device and the rolling direction RD of the rolled metal material 5 when the surface of the rolled metal material 5 is viewed from the normal direction is also referred to as the illumination angle θ30. The probability that the reading unit can decode the captured image of the marking M is also referred to as the reading rate.

[0024] As shown in FIG. 3 , the surface of the rolled metal material 5 has multiple streaks along the rolling direction RD, which is one direction. These streaks are formed by grooves with minute depths. When light L30 emitted by the lighting device 30 reaches the metal surface, it is diffusely reflected by these grooves. As shown in FIG. 3A , the amount of light L30 from the lighting device 30 that is diffusely reflected by the metal surface increases as the irradiation angle θ30 approaches 90 degrees. As shown in FIG. 3B , the amount of light L30 from the lighting device 30 that is specularly reflected by the metal surface increases as the irradiation angle θ30 approaches 0 degrees (i.e., as the optical axis of the lighting device 30 and the rolling direction RD become more parallel). In other words, the amount of diffusely reflected light decreases as the irradiation angle θ30 approaches 0 degrees.

[0025] (Verification of Captured Images of Marking M) FIG. 4 is a diagram illustrating verification results in which captured images of the can bottom 6a of the embodiment change depending on the irradiation angle θ30. FIG. 4 is a schematic illustration of the captured images. For reference, FIG. 4 also illustrates an obtuse irradiation angle θ30 greater than 90 degrees. However, basically, as long as the absolute value of the difference between the irradiation angle θ30 and 90 degrees (|θ30-90 degrees|) is the same, the conditions for the irradiation angle θ30 are the same for both acute and obtuse angles. For example, as shown in parentheses in FIG. 4, an irradiation angle θ30 = 100 degrees and an irradiation angle θ30 = 80 degrees are the same conditions.

[0026] In the verification, a marking M was engraved in the center of the can bottom 6a of an aluminum can 6 using a laser marker, and the can bottom 6a was irradiated at multiple irradiation angles θ30. The can bottom 6a was dome-shaped. The portion of the can bottom 6a where the marking M was engraved (the marking-forming portion) was within a range that could be considered to be a surface perpendicular to the can axis. The angle of incidence of light L30 on the can bottom 6a (the angle between the optical axis of the illumination light and the normal to the surface of the can bottom 6a) was 45 degrees. Images of the can bottom 6a were then captured using a reader from directly above, and verification was performed to determine whether the can identification information could be decoded from the captured image of the marking M. As shown in FIG. 4 , as the irradiation angle θ30 approached 90 degrees, the effect of diffuse reflection increased in the captured image of the marking M on the can bottom 6a, reducing the contrast between the marking M and the exposed portion of the metal surface. On the other hand, as the irradiation angle θ30 approached 0 degrees, the contrast between the marking M and the exposed portion of the metal surface increased.

[0027] Furthermore, when the irradiation angle θ30 was 80 degrees, 90 degrees, or 100 degrees, the captured image of the marking M was unclear, making it impossible to decode the can identification information. On the other hand, when the irradiation angle θ30 was 0 degrees, 60 degrees, 70 degrees, 110 degrees, 120 degrees, or 130 degrees, the captured image of the marking M was clear, making it possible to decode the can identification information. From these results, it was confirmed that when the irradiation angle θ30 was 80 degrees or more and 100 degrees or less, the captured image of the marking M was unclear, making it impossible to decode the can identification information. On the other hand, when the irradiation angle θ30 was 70 degrees or less and 110 degrees or more, the captured image of the marking M was clear, making it possible to decode the can identification information.

[0028] That is, this verification confirmed that the most difficult state for decoding based on marking M is when the irradiation angle θ30 is 90 degrees. It was also confirmed that the read rate of marking M improves as the irradiation angle θ30 deviates from this state, with the irradiation angle θ30 being centered at 90 degrees.

[0029] [Reading Units 50, 60, 70] The details of the reading units 50, 60, and 70 will be described. (Reading Unit 50 (Basic Configuration)) Fig. 5 is a three-view diagram illustrating the reading unit 50 of the embodiment. Fig. 5(A) is a left-side view of Fig. 5(B) (a view from the first illumination device 51a side in a direction perpendicular to the can axis in Fig. 5(B)). Fig. 5(B) is a diagram illustrating the reading unit 50 in a state in which the surface of the can bottom 6a of the can 6 placed at the reading position is viewed from below in the can axis direction. Fig. 5(C) is a bottom-side view of Fig. 5(B) (a view from the second illumination device 52a side in a direction perpendicular to the can axis in Fig. 5(B)). Fig. 6 is an enlarged view of a portion of Fig. 5(C) illustrating the focusing of light by the focusing lens 53 of the embodiment and the reflection of light at the rim 6b of the can bottom 6a. In the drawings, only the surface (outer surface) of the can 6 is shown, and the thickness of the can 6 is omitted. In the embodiment, the normal direction of the apex of the dome of the can bottom 6a (the surface of the can bottom 6a) coincides with the can axial direction (the direction of the central axis of the can 6). The state when viewed from the normal direction of the apex of the dome of the can bottom 6a is the same as the state when viewed from the can axial direction (the direction of the central axis of the can 6).

[0030] The reading unit 50 is the basic configuration of the reading unit of the embodiment. The reading unit 50 includes a first lighting device 51a, a second lighting device 52a, a reader 55 (one imaging unit), and a control unit 59. The first lighting device 51a, the second lighting device 52a, and the reader 55 are fixed to the periphery of the can 6 placed at the reading position by fixing members (not shown) such as brackets or stays. The first lighting device 51a and the second lighting device 52a are devices that irradiate the can bottom 6a with illumination light L51a and L52a, respectively. The first lighting device 51a is installed so that the optical axis (the central axis of the luminous flux of illumination light L51a) faces the center of the surface of the can bottom 6a (i.e., the top of the dome). The angle of incidence θ50a of illumination light L51a from the first illumination device 51a onto the surface of the can bottom 6a is set to an illuminance that allows the marking M to be decoded, for example, between 40 degrees and 55 degrees. If the angle of incidence θ50a is too small, the illuminance increases, but diffused light due to rolling becomes more likely to enter. On the other hand, if the angle of incidence is too large, the rim 6b will block the light reaching the area where the marking M is installed.

[0031] As shown in Fig. 6, the first lighting device 51a includes a condensing lens 53. The condensing lens 53 is an optical element that condenses illumination light L51a (see the hatching in Fig. 6) emitted by the first lighting device 51a onto the inside of the rim 6b of the can bottom 6a. The condensing lens 53 may be provided inside the first lighting device 51a or outside the first lighting device 51a. The height h51a of the first lighting device 51a (the distance between the light-emitting portion of the first lighting device 51a and the top of the can bottom 6a) is, for example, approximately 15 mm or more.

[0032] Here, the can bottom 6a includes a rim 6b that contacts the ground surface. The rim 6b is provided so as to protrude downward in the can axial direction from the outer edge of the can bottom 6a. Light L51d (see dotted line) that reaches the rim 6b is reflected by the surface of the rim 6b and travels toward the inside of the can bottom 6a. Thus, the reflected light traveling toward the inside of the can bottom 6a excessively increases the illuminance of the can bottom 6a or is reflected by the surface of the can bottom 6a. Therefore, such reflected light causes the captured image of the marking M to become unclear. Note that the amount of such reflected light is greater in the case of specular reflection than in the case of diffuse reflection. Therefore, the captured image of the marking M is more susceptible to the influence of light reflected by the rim 6b as the illumination angle becomes smaller (i.e., as the optical axis of the illumination light L51a of the first illumination device 51a approaches parallel to the rolling direction when viewed from the can axial direction).

[0033] The focusing lens 53 focuses the illumination light L51a from the first illumination device 51a on the inside of the rim 6b, thereby sufficiently reducing the light component that reaches the rim 6b and thereby reducing this reflected light. This allows the reading unit 50 to prevent the captured image of the marking M from becoming blurred and improve the reading rate. While FIG. 6 illustrates a configuration in which the entire illumination light L51a is focused on the inside of the rim 6b, it is sufficient if the light L51d that is about to reach the inner surface of the rim 6b (specifically, the portion of the inner surface of the rim 6b facing the first illumination device 51a) is focused on the inside of the rim 6b. This is because the light L51e (see dotted line) that reaches the outer surface of the rim 6b (the portion of the outer surface of the rim 6b facing the first illumination device 51a) is basically reflected toward the outside of the rim 6b.

[0034] The second lighting device 52a is a device similar to the first lighting device 51a. That is, the optical axis of the second lighting device 52a is oriented toward the center of the can bottom 6a. The angle of incidence of the illumination light from the second lighting device 52a on the can bottom 6a and the installation height of the second lighting device 52a are similar to those of the first lighting device 51a. Furthermore, the second lighting device 52a includes a condensing lens (not shown). As shown in FIG. 5B , when viewed from the can axial direction, the optical axis of the illumination light L51a from the first lighting device 51a and the optical axis of the illumination light L52a from the second lighting device 52a are orthogonal. That is, the angle θ50b between the two optical axes is a right angle.

[0035] The reader 55 is a device with the function of a camera that captures an image of the can bottom 6a. The optical axis O55 of the reader 55 (the optical axis of the optical lens of the reader 55) preferably coincides with the can axis direction. This reduces distortion in the captured image of the marking M when the marking M is provided near the dome-shaped top of the can bottom 6a. However, as with readers 71b, 72b, etc., described below, the optical axis of the reader may be slightly tilted with respect to the can axis, depending on the reader installation space, etc., as long as the distortion in the captured image is sufficiently small and the image of the marking M can be decoded. The installation height h55 of the reader 55 (the distance between the light entrance portion of the reader 55 and the top of the can bottom 6a) is, for example, approximately 200 mm.

[0036] With the above configuration, the control unit 59 controls the reader 55 to acquire image information of the can bottom 6a when the illumination of the first illumination device 51a is turned on (first illumination step) (first imaging step). Furthermore, the control unit 59 controls the reader 55 to acquire image information of the can bottom 6a when the illumination of the second illumination device 52a is turned on (second illumination step) after the first illumination device 51a is turned off (second imaging step). Then, the control unit 59 executes processing to decode the marking M and acquire can identification information based on these two sets of image information.

[0037] As described above, when viewed from the can axis direction, the angle θ50b formed between the optical axis of illumination light L51a and the optical axis of illumination light L52a is 90 degrees. Therefore, even if the control unit 59 cannot decode data based on one piece of image information, there is a very high probability that it can decode data based on the other piece of image information. This is because even if the illumination angle θ30 of one illumination device is within the range of 80 degrees ≦ θ30 ≦ 100 degrees, the illumination angle θ30 of the other illumination device is within the range of 0 degrees ≦ θ30 < 80 degrees or 100 degrees < θ30 ≦ 180 degrees (see FIG. 4 ). That is, more specifically, when the illumination angle θ30 of one illumination device is within the range of 80 degrees ≦ θ30 ≦ 100 degrees, the illumination angle θ30 of the other illumination device is within the range of 0 degrees ≦ θ30 ≦ 10 degrees or 170 degrees ≦ θ30 ≦ 180 degrees. Furthermore, even if the irradiation angle θ30 of one lighting device is within the range of 70 degrees < θ30 < 110 degrees, the irradiation angle θ30 of the other lighting device is within the range of 0 degrees ≦ θ30 < 20 degrees or 160 degrees < θ30 ≦ 180 degrees. Note that, with reference to the verification results in Fig. 4, in order to improve the reading rate of the marking M, it is not limited to θ50b = 90 degrees, but it is preferable that 20 degrees < θ50b < 160 degrees, and it is more preferable that 40 degrees ≦ θ50b ≦ 140 degrees.

[0038] (Reading units 60, 70) The reading units can be configured in various ways depending on the state of the can 6 to be read. That is, during the manufacturing process, the can 6 rotates around the can axis or moves due to transportation, etc. The reading units can be configured in various ways depending on the state of the can 6. The basic configuration for the reading units 60, 70 to capture an image of the can bottom 6a is the same as that of the reading unit 50. For example, the installation height of each illumination device and each reader of the reading units 60, 70 is the same as the installation height of the illumination devices 51a, 52a and reader 55 of the reading unit 50. Furthermore, the incident angle of each illumination device of the reading units 60, 70 to the can bottom 6a is the same as the incident angle of the illumination devices 51a, 52a of the reading unit 50 to the can bottom 6a. When viewed from the can axial direction, the optical axis of each first illumination device and the optical axis of each second illumination device are perpendicular to each other.

[0039] (Reading unit 60, inspection device 24) The reading unit 60 is configured to be suitable for reading the marking M when the can 6 is not rotating around the can axis but is moving (moving in a direction perpendicular to the can axis). In this embodiment, an example in which the reading unit 60 is provided in the inspection device 24 will be described. FIGS. 7 and 8 are three-sided views illustrating the reading unit 60 of this embodiment. FIGS. 7 and 8 show an example in which the reading unit 60 is installed as the reading unit 24b (see FIG. 1) near the transport wheel 24d of the inspection device 24. FIG. 7 shows a state in which the can 6 is positioned at a first position P61. FIGS. 7A to 7C correspond to the illustrated directions in FIGS. 5A to 5C, respectively. FIG. 8 shows a state in which the transport wheel 24d has rotated from the state shown in FIG. 7, causing the can 6 to be positioned at a second position P62. FIG. 8(A) is a view of FIG. 8(B) from the left side of tangent line B (a tangent line to the arc that is the movement trajectory of the center of the can 6, passing through the center of the can 6 placed at the second position P62). FIG. 8(B) is a view of the reading unit 60 in a state where the can 6 placed at the second position P62 is viewed from below in the can axial direction. FIG. 8(C) is a view of FIG. 8(B) from the outside in radial direction C (the direction of a straight line that passes through the center of the can 6 placed at the second position P62, among the diameters of the conveying wheel 24d). Note that the first reader 61b is not shown in FIGS. 7(A) and 8(A).

[0040] As shown in FIG. 7 , the inspection device 24 includes a conveying wheel 24d. The conveying wheel 24d is a disk-shaped, cylindrical, or other member. The outer periphery of the conveying wheel 24d has multiple arc-shaped notches 24e (also referred to as pockets, etc.). The cans 6 are accommodated in these notches 24e, and the conveying wheel 24d rotates around its central axis (see arrow θ 24d), moving along the outer periphery of the conveying wheel 24d (see arrow A 24d). The notches 24e may have an arc-shaped shape that opens widely outward in the radial direction. The conveying wheel 24d of the inspection device 24 is equipped with a suction device (not shown) that sucks the accommodated cans 6 and holds them in the notches 24e. This allows the conveying wheel 24d of the inspection device 24 to move the cans 6 accommodated in the notches 24e without rotating them around the can axis.

[0041] The reading unit 60 includes a first unit 61, a second unit 62, and a control unit 69. The first unit 61 reads the marking M on the can bottom 6a when the can 6 is positioned at a first position P61. The second unit 62 reads the marking M on the can bottom 6a when the can 6 is positioned at a second position P62. The second position P62 is a position rotated several degrees circumferentially from the first position P61 (see FIG. 8 ). That is, when the can 6 passes the first position P61, the first unit 61 captures an image of the marking M. Thereafter, when the can 6 moves from the first position P61 along the outer periphery and passes the second position P62, the second unit 62 captures an image of the marking M. The first position P61 and the second position P62 may be spaced apart enough so as not to interfere with the first reader 61b and the second reader 62b, which will be described later.

[0042] The first unit 61 includes a first lighting device 61a and a first reader 61b (first imaging unit). As shown in Fig. 7(B) , when viewed from the can axial direction, the optical axis of illumination light L61a from the first lighting device 61a is directed toward the center of the can 6 positioned at the first position P61 and is tangent to the arc (see arc-shaped arrow A24d) that is the movement trajectory of the center of the can 6. As shown in Fig. 7(C) , the optical axis O61b of the first reader 61b coincides with the can axial direction of the can 6 positioned at the first position P61.

[0043] The second unit 62 includes a second illumination device 62a and a second reader 62b (second imaging unit). As shown in FIG. 8A , the optical axis O62b of the second reader 62b coincides with the can axial direction of the can 6 positioned at the second position P62. The optical axis of the illumination light L62a is directed toward the center of the can bottom 6a of the can 6 positioned at the second position P62 and is normal to the arc that is the movement trajectory of the center of the can 6 when viewed from the can axial direction (i.e., the radial direction C). In this way, the second illumination device 62a and the second reader 62b are installed in accordance with the position of the can 6 after it has been moved to the second position P62. This allows the second unit 62 to read the marking M in a manner that compensates for the movement of the can 6 associated with the rotation of the conveying wheel 24d.

[0044] 7(C) and other figures, the control unit 69 controls the first lighting device 61a to irradiate the can bottom 6a with illumination light L61a when the can 6 passes through the first position P61 (first lighting step). The control unit 69 also controls the first reader 61b in synchronization with the control of the first lighting device 61a to capture an image of the can bottom 6a while the first lighting device 61a is illuminating the can bottom 6a (first imaging step). The control unit 69 then turns off the illumination of the first lighting device 61a while the can 6 moves from the first position P61 to the second position P62.

[0045] 8A and other figures, the control unit 69 then controls the second illumination device 62a to irradiate the can bottom 6a with illumination light L62a when the can 6 passes the second position P62 (second illumination step). The control unit 69 also controls the second reader 62b in synchronization with the control of the second illumination device 62a to capture an image of the can bottom 6a while the second illumination device 62a is illuminating the can bottom 6a (second imaging step). The control unit 69 then turns off the illumination of the second illumination device 62a until the next can 6 moves to the first position P61.

[0046] As a result, when the can 6 is placed at the first position P61 and the second position P62, the control unit 69 of the reading unit 60 can acquire image information of the marking M from the first reader 61b and the second reader 62b, respectively, and then acquire can identification information by decoding the image information. If the control unit 69 acquires can identification information from both the image information from the first reader 61b and the image information from the second reader 62b, it only needs to output the can identification information acquired from at least one of the readers to the control unit 24i of the inspection device 24. If the control unit 69 acquires can identification information from only one of the image information from the first reader 61b and the image information from the second reader 62b, it only needs to output the can identification information acquired from only one of the readers to the control unit 24i of the inspection device 24.

[0047] The control unit 24i of the inspection device 24 associates the can identification information acquired from the reading unit 60 with the inspection result (OK or NG) of the can 6 and outputs the information to the management device 25.

[0048] (Reading unit 70, printing device 23) The reading unit 70 is configured to be suitable for reading the marking M when the can 6 is rotating around the can axis and moving. In the embodiment, an example will be described in which the reading unit 70 is provided near the printing device 23. FIG. 9 is a diagram showing an example in which the reading unit 70 of the embodiment is attached to the mandrel wheel 23d of the printing device 23 as the reading unit 23b (see FIG. 1). FIG. 10 is an enlarged view showing the configuration near the reading unit 70 of the embodiment. The illustrated directions in FIGS. 10(A) to 10(C) correspond to the illustrated directions in FIGS. 5(A) to 5(C), respectively.

[0049] 9, the printing device 23 includes a mandrel wheel 23d, a blanket 23f, and a burnishing roller 23h. Although not shown, the printing device 23 also includes components such as a plate cylinder that applies ink to the blanket 23f. The mandrel wheel 23d rotates around its central axis (see arrow θ23d), thereby moving the can 6 held by the mandrel 23e along a circumference centered on the central axis (see arrow A23d). As will be described later, during the printing process, the can 6 held by the mandrel 23e rotates around the can axis.

[0050] The blanket 23f is a printing plate that prints on the outer circumferential surface of the can body while the can 6 is held by the mandrel 23e. In FIG. 9, the blanket number is indicated in parentheses next to the reference number of the blanket 23f. Five blankets 23f (23f(1) to 23f(5)) are fixed circumferentially to the outer circumferential surface of a cylindrical blanket roller 23g. As the blanket roller 23g rotates around its central axis (see arrow θ23g), each blanket 23f transfers ink to the outer circumferential surface of the can body of the can 6. In response, the can 6 rotates around the can axis (see arrow θ1). The burnish roller 23h is a device that applies a varnish to the outer circumferential surface of the can 6 after printing to protect the outer circumferential surface of the can 6. The varnish is attached to the outer circumferential surface of the burnish roller 23h. The burnishing roller 23h rotates in the same manner as the blanket roller 23g (see arrow θ23h) to apply the varnish to the outer peripheral surface of the can body, and the can 6 rotates around the can axis (see arrow θ2).

[0051] The reading unit 70 reads the marking M on the can bottom 6a of the can 6 after the varnish has been applied. Therefore, the reading position P70 of the reading unit 70 is the position to which the can 6 after the varnish has been applied has moved along the circumference centered on the central axis of the mandrel wheel 23d.

[0052] The reading unit 70 includes a first unit 71 and a second unit 72. The imaging operation of the second unit 72 is performed after the imaging operation of the first unit 71. However, the period between the two imaging operations is sufficiently short (e.g., 1 / 100 seconds or less). Therefore, during the period between the two imaging operations, the rotation angle of the can 6 around the can axis is, for example, 10 degrees or less, and the movement distance of the can 6 is negligibly small. In this embodiment, the first unit 71 and the second unit 72 are considered to acquire images with the can 6 positioned at the same position. In other words, the position where the can 6 is positioned when the first unit 71 and the second unit 72 image the can bottom 6a is considered to be the reading position P70.

[0053] The first unit 71 includes a first illumination device 71a and a first reader 71b (first imaging unit). The optical axis of the first illumination device 71a is the same as that of the first illumination device 61a. That is, when viewed from the can axis direction, the optical axis of the first illumination device 71a is directed toward the center of the can 6 placed at the reading position P70 and is tangent to the arc (see arc-shaped arrow A23d) that is the movement trajectory of the center of the can 6. The first reader 71b is positioned in the space above the can bottom 6a placed at the reading position P70 so that it can capture an image of the can bottom 6a. The optical axis O71b of the first reader 71b passes through the center of the can bottom 6a placed at the reading position P70. Furthermore, the optical axis O71b of the first reader 71b does not coincide with the can axis direction; that is, the optical axis O71b is positioned slightly tilted with respect to the can axis 6d (see FIG. 10A).

[0054] The second unit 72 includes a second illumination device 72a and a second reader 72b (second image capture unit). The configuration of the second illumination device 72a is the same as that of the second illumination device 62a. However, when viewed from the can axis direction, the optical axis of the illumination light L72a of the second illumination device 72a and the optical axis of the illumination light L71a of the first illumination device 71a are perpendicular to each other (see FIG. 10B ).

[0055] As shown in Figures 9 and 10(B), when viewed from the can axis direction, the first leader 71b and the second leader 72b are aligned radially around the mandrel wheel 23d. As shown in Figure 10(A), when viewed from a direction perpendicular to the can axis (a tangent to a circle centered on the central axis of the mandrel wheel 23d), the first leader 71b and the second leader 72b are positioned at the same height. Therefore, the distance between the first leader 71b and the can bottom 6a is equal to the distance between the second leader 72b and the can bottom 6a. The first leader 71b and the second leader 72b are positioned symmetrically about the can axis 6d. The angle between the optical axis O71b of the first leader 71b and the can axis 6d is equal to the angle between the optical axis O72b of the second leader 72b and the can axis 6d, e.g., approximately 5 to 10 degrees.

[0056] In this way, the first reader 71b and the second reader 72b are positioned slightly offset in the radial direction, so that they can be positioned at the same height without interfering with each other. This allows the first reader 71b and the second reader 72b to image the can bottom 6a with the can 6 positioned in the same position. The first reader 71b and the second reader 72b image the marking M on the can bottom 6a at an angle of approximately 5 to 10 degrees from the can axis. Distortion of the captured image due to this degree of tilt has almost no effect on decoding of the marking M.

[0057] 10(C), when the can 6 passes the reading position P70, the control unit 79 controls the first illumination device 71a to irradiate the can bottom 6a with illumination light L71a (first illumination step). The control unit 79 also controls the first reader 71b in synchronization with the control of the first illumination device 71a to capture an image of the can bottom 6a while the first illumination device 71a is illuminating the can bottom 6a (first imaging step). The control unit 79 controls the first illumination device 71a to turn off within 1 / 100 seconds or so after the start of illumination.

[0058] 10A, the control unit 79 then controls the illumination of the second illumination device 72a to irradiate the can bottom 6a with illumination light L72a (second illumination step). The control unit 79 also controls the second reader 72b in synchronization with the control of the second illumination device 72a to capture an image of the can bottom 6a while the second illumination device 72a is illuminating the can bottom 6a (second imaging step). The control unit 79 then turns off the illumination of the second illumination device 72a until the next can 6 moves to the reading position P70.

[0059] As a result, the control unit 79 of the reading unit 70 can acquire the image information of the marking M from each of the first reader 71b and the second reader 72b while the can 6 is placed in the same position, and then acquire the can identification information by decoding the image information. Then, similar to the control unit 69 of the reading unit 60, if the control unit 79 is able to acquire the can identification information from both the image information from the first reader 71b and the image information from the second reader 72b, it only needs to output the can identification information acquired from at least one of the readers to the control unit 23i of the printing device 23. Furthermore, if the control unit 79 is able to acquire the can identification information from only one of the image information from the first reader 71b and the image information from the second reader 72b, it only needs to output the can identification information acquired from only one of the readers to the control unit 23i of the printing device 23.

[0060] During the period between the time when the first reader 71b acquires the image information and the time when the second reader 72b acquires the image information, the can 6 held by the mandrel 23e rotates around the can axis due to inertia as the burnishing roller 23h rotates. This period is within 1 / 100 seconds, for example. Therefore, the rotation angle of the can 6 during this period is within 10 degrees, for example. Furthermore, when viewed from the can axis direction, the angle formed by the optical axis of the first lighting device 71a and the optical axis of the second lighting device 72a is 90 degrees. Therefore, even if the irradiation angle θ30 (see FIG. 4) of one of the first lighting device 71a and the second lighting device 72a is greater than or equal to 80 degrees and less than or equal to 100 degrees (i.e., |θ30 - 90 degrees|≦10 degrees), the irradiation angle θ30 of the other lighting device is less than 80 degrees or greater than 100 degrees. That is, as described above, when the illumination angle θ30 of one illumination device is within the range of 80 degrees≦θ30≦100 degrees, the illumination angle θ30 of the other illumination device is within the range of 0 degrees≦θ30≦10 degrees or 170 degrees≦θ30≦180 degrees. In this case, even if can 6 rotates by approximately 10 degrees due to inertia, the other illumination angle θ30 is within the range of 0 degrees≦θ30≦20 degrees or 160 degrees≦θ30≦180 degrees (i.e., 20 degrees≦|θ30-90 degrees|). This allows control unit 79 to improve the probability of being able to decode marking M based on the image captured by the other of first reader 71b and second reader 72b.

[0061] The control unit 23i of the printing device 23 associates the can identification information, blanket numbers (1 to 5), and printing plate number (not shown) obtained from the reading unit 70, and outputs them to the management device 25. The control unit 79 can determine the number of the mandrel 23e that held the can 6 when printing each can 6, the blanket numbers 1 to 5, and the printing plate number, using a detection unit such as an encoder. The control unit 23i can also determine which of the multiple mandrels 23e is located at the printing position or the reading position. Therefore, the control unit 23i can associate the blanket numbers 1 to 5 with the can identification information obtained based on the image information of the can 6 placed at the reading position.

[0062] As described above, the reading units 60 and 70 are attached to the inspection device 24 and the printing device 23, respectively. However, the reading units can have various configurations depending on the manufacturing device to which they are attached. For example, a reading unit attached to a manufacturing device in which the cans 6 do not rotate around their axes and do not move the cans 6 may have the same basic configuration as the reading unit 50 (see FIG. 5 ). In this case, the first lighting device 51 a and the second lighting device 52 a sequentially illuminate the can bottoms 6 a of the cans 6 arranged in the same position (first lighting step, second lighting step), and the reader 55 captures images of the can bottoms 6 a at the respective illumination timings of the first lighting device 51 a and the second lighting device 52 a (first imaging step, second imaging step).

[0063] Furthermore, in a manufacturing apparatus (e.g., a printing apparatus 23) in which the cans 6 rotate around their axes and move, the first lighting device may irradiate light of a first wavelength, and the second lighting device may irradiate light of a second wavelength, which is different from the first wavelength. In this case, the first lighting device and the second lighting device may simultaneously irradiate light of the first wavelength and light of the second wavelength onto the cans 6 arranged in the same position (first lighting step, second lighting step). In this case, the first reader may be a device capable of capturing an image of the light of the first wavelength reflected by the can bottom 6 a, and the second reader may be a device capable of capturing an image of the light of the second wavelength reflected by the can bottom 6 a. The first reader and the second reader may capture an image of the can bottom 6 a at the same irradiation timing of the first lighting device and the second lighting device (first imaging step, second imaging step).

[0064] In addition, if the reader is a device capable of capturing images of the first wavelength light and the second wavelength light independently, one reader may serve as both the first reader and the second reader. In this case, the reader may be configured to be able to acquire multiple captured images by continuously capturing images in one imaging operation, or may be configured to include a half mirror or the like that separates the subject light.

[0065] As described above, the reading unit of this embodiment can improve the reading rate of the marking M shown on the can bottom 6a of the can 6 during the manufacturing process.

[0066] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and variations, such as the modified embodiments described below, are possible, and these are also within the technical scope of the present invention. Furthermore, the effects described in the embodiments are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments. Note that the configurations of the above-described embodiments and the modified embodiments described below can be used only in part, or in appropriate combination, and detailed description thereof will be omitted.

[0067] (Modifications) (1) In the embodiment, the manufacturing system includes a cupping press device, a can body processing device, a printing device, and an inspection device, but is not limited to this. The manufacturing system may also include various devices for manufacturing cans (for example, a cleaning device, a neck processing device that performs a drawing process on the opening edge of the can, etc.). Furthermore, the reading unit may be provided in a device that fills empty cans with beverages, etc.

[0068] (2) In the embodiment, the angle between the optical axis of the first lighting device and the optical axis of the second lighting device when viewed from the can axis direction is 90 degrees, but this is not limited to this. This angle may be large enough so that when one of the two readers cannot decode the can identification information based on the marking included in the captured image, the other reader can decode the can identification information based on the captured image. In other words, this angle may be large enough so that the can identification information can be decoded based on at least one of the two captured images acquired by the two readers.

[0069] (3) In the embodiment, the marking is formed by laser marking or printing ink, but this is not limited thereto. The marking may be formed, for example, by attaching a sticker. Note that, in the case of a metal molded can to which paint is applied in a spray process, the print contrast is reduced. Markings formed by laser marking are easily affected by paint, but the method of the embodiment is less susceptible to diffused light from lighting compared to, for example, ring lighting. This makes it possible to suppress a decrease in readability after paint application, even for markings formed by laser marking. (4) In the embodiment, the can is transported circumferentially, but this is not limited thereto. The can may be transported, for example, in a straight line.

[0070] (5) In the embodiment, an example in which the lighting device includes a condensing lens is shown, but this is not limiting. For example, if the rim does not block the light from the lighting device, such as when the distance between the lighting device and the bottom of the can is sufficiently small, the lighting device does not need to include a condensing lens. On the other hand, if the rim blocks the light from the lighting device, such as when the distance between the lighting device and the bottom of the can is large, the lighting device may include a condensing lens.

[0071] (6) In the embodiment, the marking formation portion (the portion on which the marking is formed) is the bottom of the metal can, but this is not limited thereto. The marking formation portion is not limited to the surface of the metal can and may be within an area that can be imaged by the reading unit, and may be, for example, the peripheral surface of the can body or the top surface of the can lid. Furthermore, the markings read by the reading unit are not limited to markings formed on the metal can, but may also be markings formed on other metal formed products (including those that involve predetermined movement or rotation) manufactured by shaping rolled metal material. Furthermore, the shape of the metal can is not limited to a cylindrical shape, but may be an approximately cylindrical shape (including a cross-sectional shape that is an elliptical curve), or may be a circular or approximately circular cross-sectional shape (including an elliptical shape).

[0072] 1: Management system 6: Can 6a: Can bottom 6b: Rim 21b, 22b, 23b, 24b, 50, 60, 70: Reading unit 30: Illumination device 51a, 61a, 71a: First illumination device 52a, 62a, 72a: Second illumination device 53: Condenser lens 55: Reader 61, 71: First unit 61b, 71b: First reader 62, 72: Second unit 62b, 72b: Second reader M: Marking

Claims

1. A marking reading device for a marking shown on a marking formation section on the surface of a metal molded product manufactured from a rolled metal plate, comprising: a first illumination unit that irradiates light onto the marking formation section; a first imaging unit that images the marking in synchronization with the irradiation timing of the first illumination unit; a second illumination unit that irradiates light onto the marking formation section from a direction different from that of the first illumination unit while the marking formation section is viewed from the normal direction; and a second imaging unit that images the marking in synchronization with the irradiation timing of the second illumination unit.

2. The marking reading device for metal molded products according to claim 1, characterized in that the cross-sectional shape of the metal molded product is approximately circular.

3. A marking reading device for a metal molded product according to claim 1 or 2, characterized in that the metal molded product is substantially cylindrical in shape.

4. A marking reading device for a metal molded product according to any one of claims 1 to 3, characterized in that the metal molded product is a metal molded can, and the marking forming portion is the can bottom of the metal molded can.

5. The marking reading device for metal molded products described in any one of claims 1 to 4, characterized in that the marking reading device is a device that images the marking on the marking forming portion when the metal molded product is positioned at a first position and a second position moved from the first position, and when the metal molded product is positioned at the first position, the first illumination unit is positioned at a position to irradiate light onto the marking forming portion and the first imaging unit is positioned at a position to image the marking, and when the metal molded product is positioned at the second position, the second illumination unit is positioned at a position to irradiate light onto the marking forming portion and the second imaging unit is positioned at a position to image the marking.

6. A marking reading device for metal molded products as described in any one of claims 1 to 5, characterized in that the marking reading device is a device that images the marking on the marking forming section while the metal molded product is stationary, the first illumination section and the second illumination section irradiate light onto the marking forming section at different timings, the first imaging section and the second imaging section are combined into a single imaging section, and the single imaging section images the marking at the respective irradiation timings of the first illumination section and the second illumination section.

7. The marking reading device is a device that images the marking on the marking forming portion when the metal molded product is rotating and when the metal molded product is disposed at a first position and a second position moved from the first position, the first position and the second position are small enough that the distance between them can be approximated to be the same position, and the amount of rotational movement of the metal molded product between the first position and the second position is sufficiently small, when the metal molded product is disposed at the first position, the first illumination unit is disposed at a position to irradiate light onto the marking forming portion and the first imaging unit is disposed at a position to image the marking, and when the metal molded product is disposed at the second position, the second illumination unit is disposed at a position to irradiate light onto the marking forming portion and the second imaging unit is disposed at a position to image the marking. A marking reading device for metal molded products as described in any one of claims 1 to 6, characterized in that:

8. The marking reading device for metal molded products described in any one of claims 1 to 7, characterized in that the marking reading device is a device that images the marking on the marking forming section while the metal molded product is rotating and moving, the first illumination unit irradiates light of a first wavelength, the second illumination unit irradiates light of a second wavelength different from the first wavelength at the same timing as the first illumination unit, the first imaging unit reads the marking based on the intensity of light corresponding to the first wavelength, and the second imaging unit images the marking based on the intensity of light corresponding to the second wavelength.

9. A marking reading device for metal molded products as described in any one of claims 1 to 8, characterized in that the marking has encoded information, and when the marking formation portion of the metal molded product placed at the reading position is viewed from the normal direction, the angle formed by the irradiation direction of the first illumination unit and the irradiation direction of the second illumination unit is such that the marking can be decoded based on at least one of the imaging information acquired by the first imaging unit and the imaging information acquired by the second imaging unit.

10. A marking reading device for metal molded products as described in claim 9, characterized in that when the marking formation portion of the metal molded product placed at the reading position is viewed from the normal direction, the angle θ formed by the irradiation direction of the first lighting unit and the irradiation direction of the second lighting unit is 20 degrees < θ < 160 degrees.

11. The marking reading device for metal molded products described in claim 4, characterized in that the bottom of the metal molded can has a protrusion that protrudes downward within an annular range, the marking is provided on the surface inside the annular range, and the first lighting unit and the second lighting unit focus illumination light inside the annular range.

12. A management system for metal molded products comprising: a plurality of processing devices of different types that execute a process for manufacturing the metal molded products; a metal molded product marking reading device as described in any one of claims 1 to 4 that is provided in each of the plurality of processing devices; and a management device that is capable of communicating with each of the processing devices, wherein the marking has identification information of the metal molded product, and each of the processing devices correlates the read information of the marking acquired by each of the marking reading devices with processing information and outputs the correlated information to the management device, and the management device comprises a memory unit and a control unit that executes a process of correlating the identification information of each of the metal molded products with the processing information of the plurality of types of the processing devices and storing the correlated information in the memory unit based on the output of the plurality of processing devices.

13. A method for reading markings shown on a marking formation portion on the surface of a metal molded product manufactured from a rolled metal plate, comprising: a first illumination process for irradiating light onto the marking formation portion; a first imaging process for imaging the marking in synchronization with the irradiation timing of the first illumination process; a second illumination process for irradiating light onto the marking formation portion from a direction different from that of the first illumination process while viewing the marking formation portion from the normal direction; and a second imaging process for imaging the marking in synchronization with the irradiation timing of the second illumination process.

Images