Management device for manufactured product, and management method for manufactured product

Abstract

To provide a management device capable of managing a manufactured product having a welded portion.SOLUTION: One example of a manufactured product 10 is a suspension for a disk device. The manufactured product 10 has a welded portion. A management device 60 comprises: a camera 63; a control portion 66; and a database 68. Information of the manufactured product 10 is associated with a manufactured product ID and they are stored in a database 68. The welded portion of the manufactured product 10 is imaged, then a nugget pattern is image processed, for acquiring pattern data. The pattern data is associated with the manufactured product ID, and is stored in the database 68. A welded portion of a manufactured product 10A having an unknown manufactured product ID, is imaged, then a nugget pattern is image processed, consequently collation data is acquired. The collation data is collated with existing pattern data, and if the collation data and the existing pattern data match, a manufactured product ID associated with the existing pattern data is acquired.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a management device and a management method for managing a workpiece having a welded portion. [Background technology]

[0002] Laser welding as described in Patent Document 1 may be used when manufacturing a work piece consisting of multiple small metal plates, such as a suspension for a disk drive. For example, a suspension for a disk drive includes a base plate, a load beam, and a flexure arranged along the load beam. The base plate, the load beam, and the flexure are made of stainless steel plates. Spot welding using a laser beam is applied to fix the flexure to the load beam and to fix the load beam to the base plate.

[0003] Products such as disk drive suspensions, which are required to be of high quality and are manufactured through multiple processes, require special management to maintain quality. For example, it has been desirable to assign an ID to each product to identify the product manufactured, in order to know whether it was manufactured under appropriate production conditions in each process. Alternatively, as described in Patent Document 2, a production management system has been proposed that uses hash values ​​to manage electronic equipment parts. In this specification, ID is an abbreviation for identification. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-95934 A [Patent Document 2] JP 2023-00687 A Summary of the Invention [Problem to be solved by the invention]

[0005] For extremely small products such as disk drive suspensions, it is difficult to display an identifiable ID such as a two-dimensional code or numbers on a part of the product. Even if it is possible to display an ID on the product, providing such a display on the product may have some effect on the product. According to a production management system using a hash value as in Patent Document 2, the product can be strictly managed. However, the system is large-scale and lacks simplicity, making it difficult to use depending on the purpose.

[0006] An object of the present invention is to provide a management device and a management method capable of managing products having welds formed by laser spot welding or the like. [Means for solving the problem]

[0007] One embodiment is a management device for managing a workpiece having a welded portion, and includes a camera, an image processing unit, a control unit, a database, etc. A plurality of product IDs are stored in the database, for example, in consecutive numbers, and each product ID is associated with product information and stored. The camera photographs the welded portion of the workpiece. The image processing unit obtains pattern data by performing image processing on the nugget pattern of the photographed welded portion. The control unit associates the pattern data with the product ID and stores it in the database.

[0008] The management device of this embodiment may include a camera that photographs the welded portion of a workpiece to be traced (a workpiece whose product ID is unknown), an image processing unit that acquires matching data corresponding to the nugget pattern by image processing the nugget pattern of the photographed welded portion, and a control unit for matching. The control unit compares the matching data with the existing pattern data stored in the database. If the matching data matches the existing pattern data, the product ID linked to the existing pattern data is obtained. If the product ID is known, product information (detailed information about the workpiece, etc.) corresponding to the product ID can be obtained.

[0009] An example of the product may be a suspension for a disk drive having a plurality of types of welds. The image processing unit may perform image processing of nugget patterns of the plurality of types of the welds and obtain pattern data corresponding to these nugget patterns.

[0010] A plurality of the products may be mounted on a frame, and the frame may have a frame ID. The frame ID and the product ID may be associated with each other and stored in the database. The camera may take an image of, for example, a front nugget portion of the welded portion. The management device of one embodiment may further include an appearance inspection unit that judges whether an appearance shape of the welded portion is good or bad.

[0011] In one embodiment of a method for managing a product, product information of the product is associated with a product ID and stored in a database. In a process of acquiring pattern data, the welded portion of the product is photographed. The nugget pattern of the photographed welded portion is image-processed to obtain pattern data corresponding to the nugget pattern. The pattern data is then associated with the product ID and stored in a database.

[0012] The management method of the present embodiment may further include a matching process. In this matching process, a weld of a workpiece (a workpiece to be traced) whose product ID is unknown is photographed. The nugget pattern of the photographed weld is image-processed to obtain matching data corresponding to the nugget pattern. This matching data is matched with the existing pattern data stored in a database. When the matching data matches the existing pattern data, the product ID associated with the existing pattern data is obtained. Information on the workpiece can be obtained based on this product ID. Effect of the Invention

[0013] According to the present invention, when managing a product having a welded portion, characterized pattern data can be obtained based on an image of a nugget pattern of the welded portion. For a product whose product ID is unknown, the welded portion of the product is photographed to obtain comparison data corresponding to the nugget pattern. The product ID can be obtained by comparing the comparison data with the existing pattern data. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a top view of an example workpiece having a plurality of welds; [Diagram 2] 2 is an enlarged plan view of a first weld of the workpiece shown in FIG. 1; [Diagram 3] 3 is a cross-sectional view of the first welded portion taken along line F3-F3 in FIG. 2 . [Figure 4] FIG. 2 is an enlarged plan view of the second weld shown in FIG. 1 . [Diagram 5] FIG. 2 is an enlarged plan view of the third weld shown in FIG. 1 . [Figure 6] FIG. 2 is a front view showing a schematic diagram of the laser welding apparatus; [Figure 7] 7 is a cross-sectional view of a portion of the laser welding apparatus shown in FIG. 6 and a first weld. [Figure 8] FIG. 1 is a perspective view showing a management device and a plurality of products according to an embodiment. [Figure 9]10 is a flowchart showing a pattern data acquisition process of a management method according to one embodiment. [Figure 10] FIG. 4 is a plan view showing a first example of an image-processed first weld; [Figure 11] FIG. 11 is a plan view showing a second example of an image-processed first weld; [Figure 12] FIG. 11 is a plan view showing a third example of an image-processed first weld; [Figure 13] 1 is a flow chart illustrating a matching process of a management method according to one embodiment. [Figure 14] 1 is a perspective view showing a schematic diagram of a part of a management device according to an embodiment and a workpiece to be traced; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a product management device and a product management method according to one embodiment will be described with reference to FIGS. Fig. 1 shows a suspension for a disk drive as an example of a product 10 having a plurality of welds. The product 10 shown in Fig. 1 includes a first plate 11, a second plate 12, and a third plate 13. In the case of the suspension for a disk drive, the first plate 11 is a load beam, the second plate 12 is a flexure, and the third plate 13 is a base plate.

[0016] The first plate 11, the second plate 12, and the third plate 13 are each made of stainless steel. An example of stainless steel is austenitic stainless steel such as SUS304. The chemical components of SUS304 are C: 0.08 or less, Si: 1.00 or less, Mn: 2.00 or less, Ni: 8.00 to 10.50, Cr: 18.00 to 20.00, and the balance is Fe.

[0017] The first plate (load beam) 11, the second plate (flexure) 12, and the third plate (base plate) 13 have different thicknesses. The thickness of the first plate 11 is greater than the thickness of the second plate 12. The thickness of the first plate 11 is, for example, 100 μm or less. An example of the thickness of the second plate 12 is 18 μm. The thickness of the third plate 13 is greater than the thickness of the first plate 11. The thickness of the third plate 13 is, for example, 200 μm or less. A wiring portion 15 is formed along the second plate 12. The wiring portion 15 includes an insulating layer made of insulating resin such as polyimide, and a conductor made of copper.

[0018] The first plate 11 and the second plate 12 are fixed to each other by a first welded portion W1. The second plate 12 and the third plate 13 are fixed to each other by a second welded portion W2. The first plate 11, the second plate 12 and the third plate 13 are fixed to each other by a third welded portion W3. In addition to these welded portions W1, W2, and W3, welded portions W are provided as necessary.

[0019] The welded parts W, W1, W2, and W3 are all formed by laser spot welding. In this specification, the side irradiated with the laser light is referred to as the front side, and the side opposite to the laser light irradiation is referred to as the back side. The workpiece (product 10) of this embodiment has a welded part W3 where three plates are overlapped. However, some workpieces do not have such a welded part with three plates overlapped.

[0020] Fig. 2 is a plan view of the first welded portion W1 as viewed from the front side. As shown in Fig. 2, the first welded portion W1 is generally circular in plan view. In other words, it is not necessarily a perfect circle in the strict sense, but is actually a shape close to a distorted circle, an ellipse, or a shape close to a circle in some other sense. A unique nugget pattern 20 that occurs during welding is formed on the surface of the first welded portion W1. The nugget pattern 20 can also be visually observed under magnification.

[0021] Fig. 3 is a cross-sectional view of the first welded portion W1 taken along the line F3-F3 in Fig. 2. As shown in Fig. 3, a first plate (load beam) 11 having a thickness T1 and a second plate (flexure) 12 having a thickness T2 are welded by the first welded portion W1. The first welded portion W1 includes a front nugget portion 21 formed in the second plate 12 and a back nugget portion 22 formed in the first plate 11.

[0022] A diameter D1 of the front nugget portion 21 is larger than a diameter D2 of the back nugget portion 22. The nugget pattern 20 is formed in the front nugget portion 21. Depending on the workpiece, the back nugget portion 22 may not penetrate the first plate 11 in the thickness direction. In that case, the diameter D2 of the back nugget portion 22 is not observed.

[0023] Fig. 4 is a plan view of the second welded portion W2. The second welded portion W2 is formed by irradiating a laser beam onto a portion where the first plate 11 and the third plate 13 overlap each other. The laser beam is irradiated from, for example, the front side of the first plate 11. As shown in Fig. 4, a unique nugget pattern 30 that occurs during welding is formed in the front nugget portion 31.

[0024] Because the first weld W1 and the second weld W2 are welded under different conditions, the diameter D3 (shown in FIG. 4) of the second weld W2 is different from the diameter D1 (shown in FIG. 3) of the first weld W1. Moreover, the nugget pattern 30 of the second weld W2 is significantly different from the nugget pattern 20 of the first weld W1.

[0025] The reason why the nugget pattern 20 of the first welded portion W1 and the nugget pattern 30 of the second welded portion W2 are different from each other is because the irradiation conditions of the laser light used for welding, the thicknesses of the two plates to be welded, etc. A unique nugget pattern 30 may be generated depending on the surface roughness of the welded plates, the way in which the inert gas flowing toward the weld hits them, the atmospheric temperature, etc.

[0026] Fig. 5 is a plan view of the third welded portion W3. The third welded portion W3 is formed by irradiating a laser beam onto a portion where the first plate 11, the second plate 12, and the third plate 13 overlap each other. The laser beam is irradiated from, for example, the front side of the second plate 12. As shown in Fig. 5, a unique nugget pattern 40 that occurs during welding is formed in a front nugget portion 41 of the third welded portion W3.

[0027] The welding conditions of the third welded portion W3 are different from those of the first welded portion W1 and the second welded portion W2. Therefore, the diameter D4 of the third welded portion W3 is different from the diameter D1 of the first welded portion W1 (shown in FIG. 3) and the diameter D3 of the second welded portion W2 (shown in FIG. 4). Moreover, the nugget pattern 40 of the third welded portion W3 (shown in FIG. 5) is quite different from the nugget pattern 20 of the first welded portion W1 and the nugget pattern 30 of the second welded portion W2. This is due to differences in welding conditions such as the irradiation conditions of the laser light, the fact that the three plates 11, 12, and 13 overlap in the third welded portion W3, and the state of the holding jig. A unique nugget pattern 40 may be generated depending on the surface roughness of the welded plate, the way in which the inert gas flowing toward the welded portion hits it, the atmospheric temperature, and the like.

[0028] 6 is a schematic diagram showing an example of a laser welding apparatus 50. The laser welding apparatus 50 has a function of welding a plurality of welds (e.g., welds W, W1, W2, and W3) by using a laser beam 51 emitted in a pulsed manner. The laser welding apparatus 50 includes a work support section 52 that supports a workpiece 10 to be welded, a laser irradiation section 53, a laser beam control section 54, and a laser oscillator 55 that is a source of the laser beam. The laser irradiation section 53 and the laser oscillator 55 are optically connected to each other by an optical fiber 58.

[0029] The laser irradiation unit 53 includes an optical lens system 56 and a galvanometer scanner as a scanning mechanism. The galvanometer scanner moves the laser light 51 emitted from the laser irradiation unit 53 sequentially toward the welds W, W1, W2, and W3. The laser light control unit 54 includes an electrical configuration for controlling the laser oscillator 55, software for control, a memory for storing control data, and the like.

[0030] 7 is a cross-sectional view that shows a schematic diagram of a part of the laser welding device 50 and the first welded portion W1. For example, the first plate 11 and the second plate 12 are placed on the workpiece support portion 52 and supported by a pressing jig 57, and then the laser beam 51 is irradiated. A part of the first plate 11 and a part of the second plate 12 are melted by the laser beam 51 and solidified to form the first welded portion W1. During this welding process, a first nugget pattern 20 is formed in the first welded portion W1. FIG. 2 shows an example of the first nugget pattern 20.

[0031] By moving the laser beam 51 using a galvano scanner or the like, a second welded portion W2 is formed in the same manner as the first welded portion W1, and further a third welded portion W3 is formed, however, the order of welding can be selected as necessary.

[0032] As shown in Fig. 4, a second nugget pattern 30 is formed on the surface of the second welded portion W2. As shown in Fig. 5, a third nugget pattern is formed on the surface of the third welded portion W3. These nugget patterns 20, 30, 40 have unique characteristics like a human fingerprint, depending on the welding conditions, etc.

[0033] In the product management device and management method according to this embodiment, at least some of the nugget patterns of the welded parts W1, W2, and W3 are imaged and pattern data is obtained by image processing. For example, pattern data is obtained according to image data of the first nugget pattern 20, the second nugget pattern 30, and the third nugget pattern 40. Alternatively, at least some of the first nugget pattern 20, the second nugget pattern 30, and the third nugget pattern 40 are characterized by image processing such as binarization and a predetermined algorithm to obtain pattern data.

[0034] 8 is a perspective view showing a management device 60 according to one embodiment. The management device 60 includes a work support member 61 on which the workpiece 10 is placed, a moving mechanism 62, a camera 63, an appearance inspection unit 64, a control unit 66 including an image processing unit 65, a display unit 67, and a database 68. The workpieces 10 are connected to a frame 70 at a predetermined pitch P1. The workpieces 10 and the frame 70 form a sheet-like work (suspension assembly 71).

[0035] A frame ID (referred to as a frame ID 72 in this specification), such as a two-dimensional code or a bar code, is provided on the frame 70 of the suspension assembly 71. Since a plurality of finished products 10 are provided on the frame 70, product IDs for identifying these finished products 10 are stored in the database 68, for example, as consecutive numbers. The database 68 also stores various kinds of product information related to the finished products 10 for each product ID, such as the date and place when the finished product 10 was produced, the processing conditions, the material, and the like. Therefore, if the product ID can be known, the production history of the finished product 10 and product information such as the materials used can be obtained from the database 68.

[0036] The moving mechanism 62 includes a guide member 80 and an actuator 81 such as a servo motor. The actuator 81 can move the work support member 61 and the suspension assembly 71 at a predetermined pitch P1 along the guide member 80. The camera 63 photographs the welds W, W1, W2, and W3 of the work 10.

[0037] An appearance inspection unit 64, which is a part of the management device 60, judges whether the appearance of the welds W, W1, W2, W3 (e.g., the size, shape, color, etc. of the welds) falls within a standard range. If it is judged to be unacceptable, some problem may have occurred in the manufacturing process, so measures are taken to prohibit the use of the suspension assembly 71 including the rejected product 10.

[0038] The image processing unit 65 digitizes the nugget patterns of the welds W1, W2, and W3 photographed by the camera 63 using image processing such as binarization and a predetermined algorithm to obtain pattern data. This pattern data is linked to the product ID by the control unit 66 and stored in the database 68.

[0039] Fig. 9 is a flow chart showing an example of a pattern data acquisition process. In the pattern data acquisition process of this embodiment, pattern data is acquired based on an image of a weld (nugget pattern). That is, in step S1 in Fig. 9, a weld (for example, first weld W1) is photographed by camera 63, and an image of the nugget pattern is generated.

[0040] In step S2 in Fig. 9, the nugget pattern of the welded part that has been photographed is processed by image processing unit 65. For example, image processing is performed using binarization and a predetermined algorithm, and the nugget pattern of the welded part is digitized. By digitizing the nugget pattern, characteristics of the welded part are extracted. The photographed nugget pattern may be displayed on display unit 67. Also, step S2 for processing the image may be performed after step S3.

[0041] As shown in Figures 2, 4 and 5, the multiple types of welds W1, W2, and W3 have nugget patterns 20, 30, and 40 that are significantly different from one another. Therefore, by combining the features of these nugget patterns, the amount of information required for identification can be increased. In other words, by combining the features of the nugget patterns of multiple different types of welds, the characterization threshold can be lowered, making it easier to identify products.

[0042] Nugget patterns 20 of multiple first welds W1 of the same type have distinguishable characteristics like human fingerprints. Nugget patterns 30 of multiple second welds W2 of the same type also have distinguishable characteristics. Nugget patterns 40 of multiple third welds W3 of the same type also have distinguishable characteristics. For this reason, only nugget patterns of welds of the same type may be extracted.

[0043] Fig. 10 shows a first example of a nugget pattern of the first welded portion W1 that has been image-processed. Fig. 11 shows a second example of a nugget pattern of the first welded portion W1 that has been image-processed. Fig. 12 shows a third example of a nugget pattern of the first welded portion W1 that has been image-processed. In this way, even multiple welds of the same type have different nugget patterns.

[0044] In step S3 in Fig. 9, it is determined whether or not all of the welds to be photographed have been photographed. If all of the welds have been photographed ("YES" in step S3), the process proceeds to step S4. If all of the welds have not been photographed ("NO" in step S3), the process returns to step S1 and the next weld is photographed. Note that step S2 may be performed after step S3.

[0045] 9, the nugget patterns of each product are digitized, and pattern data corresponding to each nugget pattern is obtained. In step S5, the obtained pattern data is linked to the product ID and stored in database 68. In this specification, the pattern data linked to the product ID is referred to as existing pattern data.

[0046] In step S6, the pattern data acquired in step S4 may be linked to the frame ID 72. By linking the pattern data to the frame ID 72, it becomes possible to obtain information corresponding to the frame ID 72 from the database 68.

[0047] If there is no need to link the pattern data to the frame ID, step S6 may be omitted. In yet another embodiment, the image of the nugget pattern captured by the camera 63 may be recorded in the database 68 as pattern data, and the image may be linked to the product ID or the frame ID.

[0048] The management device 60 of this embodiment includes an appearance inspection unit 64 (shown in FIG. 8) for inspecting the appearance of the welded portion. Therefore, it is possible to perform both the appearance inspection of the welded portion and the acquisition of pattern data. However, the appearance inspection unit 64 may be provided separately from the management device 60.

[0049] The finished product 10 from which the pattern data has been acquired is then separated from the frame 70 (shown in FIG. 8) in a subsequent process. The finished product 10 is then incorporated into a specific electronic device (e.g., a disk drive). When the finished product is extremely small, such as a suspension for a disk drive, it is difficult to display a product ID, such as a two-dimensional code or numbers, on the finished product itself.

[0050] Even if it is possible to display the product ID on the workpiece itself, such display may have some effect on the workpiece. For this reason, it is desirable to avoid displaying the product ID on the workpiece itself. However, there are cases where it is desired to know information such as the manufacturing history and materials used of a workpiece whose product ID is unknown. In this specification and FIG. 13, a workpiece whose product ID is unknown is referred to as a workpiece to be identified or a workpiece to be traced 10A. A workpiece to be traced 10A is a workpiece whose manufacturing history and materials used need to be known for some reason, such as a workpiece in which a defect has been found in a later process.

[0051] The management method of this embodiment implements a matching process as described below. Fig. 13 is a flow chart showing an example of the collation process. Fig. 14 shows a schematic diagram of a management device 60A used in the collation process. A workpiece 10A to be traced is placed on a work placement table 91.

[0052] As shown in Fig. 14, the management device 60A used in the matching process may be the same as the management device 60 (shown in Fig. 8) used in the pattern data acquisition process. That is, this management device 60A has a camera 63, an image processing unit 65, a control unit 66, a display unit 67, and a database 68. In other embodiments, the management device 60A used in the matching process may be different from the management device 60 used in the pattern data acquisition process.

[0053] In step S10 in Fig. 13, the welded portion of the workpiece 10A to be traced is photographed by the camera 63, and an image of the nugget pattern is generated. This image of the nugget pattern is processed by the image processing unit 65 in step S11. For example, the image of the nugget pattern is processed by image processing such as binarization common to the above-mentioned pattern data acquisition process. The photographed nugget pattern may be displayed on the display unit 67. Note that step S11 of processing the image may be performed after step S12.

[0054] In step S12, it is determined whether or not all of the welds to be photographed have been photographed. If all of the welds have been photographed ("YES" in step S12), the process proceeds to step S13. If all of the welds have not been photographed ("NO" in step S12), the process returns to step S10 and the next weld is photographed.

[0055] 13, the nugget pattern of the workpiece 10A is digitized by a predetermined algorithm to obtain matching data. In step S14, the matching data obtained in step S13 is matched with existing pattern data stored in the database 68. For example, the matching data and the existing pattern data are matched by the control unit 66.

[0056] 13, if the matching data matches the existing pattern data ("YES" in step S15), the process proceeds to step S16. If the matching data does not match the existing pattern data ("NO" in step S15), the process returns to step S14 and continues matching the matching data with the existing pattern data.

[0057] In step S16, a product ID recorded in the database 68 is identified based on the existing pattern data ID that matches the verification data. If the product ID is linked to a frame ID, the frame ID is also identified. By identifying the product ID and frame ID recorded in the database 68, it is possible to know information such as the manufacturing history of the workpiece 10A and the materials used. The obtained information may be displayed on the display unit 67 or may be printed out by a printer.

[0058] As described above, according to the management device and the management method of the present embodiment, the product ID and the frame ID of the product can be known based on the pattern data obtained from the image of the nugget pattern of the product having the welded portion, and the information of the product can be traced. Therefore, it is not necessary to provide the product ID dedicated for management to the product itself, and it is also possible to prevent the product ID from affecting the product.

[0059] In carrying out the present invention, it goes without saying that the specific aspects of the camera, image processing unit, display unit, database, control unit, etc. that constitute the management device can be variously modified as necessary. Furthermore, the present invention can be applied to the management of products other than suspensions for disk drives. [Explanation of symbols]

[0060] 10, 10A...product (suspension for disk device), 11...first plate, 12...second plate, 13...third plate, W, W1, W2, W3...welded part, 20, 30, 40...nugget pattern, 50...laser welding device, 51...laser light, 53...laser irradiation section, 54...laser light control section, 55...laser oscillator, 60, 60A...management device, 63...camera, 64...visual inspection section, 65...image processing section, 66...control section, 67...display section, 68...database, 70...frame, 72...frame ID.

Claims

1. A management device for managing a workpiece having a welded portion, a database in which information on the product and a product ID are associated with each other and stored; A camera for photographing the welded portion of the workpiece; an image processing unit that processes the image of the nugget pattern of the welded portion to obtain pattern data; a control unit that associates the pattern data with the product ID and stores the associated data in the database; A product management device comprising:

2. 2. The management device according to claim 1, A camera for photographing the welds of the workpiece to be traced; an image processing unit that processes an image of a nugget pattern of the welded portion and acquires matching data corresponding to the nugget pattern; a control unit that compares the matching data with the existing pattern data stored in the database, and, when the matching data matches the existing pattern data, obtains a product ID corresponding to the existing pattern data; A management device comprising:

3. 2. The management device according to claim 1, the product is a suspension for a disk drive having a plurality of types of welded parts, The image processing unit A management device that performs image processing on the nugget patterns of the plurality of types of welds and acquires the pattern data corresponding to these nugget patterns.

4. 2. The management device according to claim 1, A frame having a plurality of said works provided thereon has a frame ID; A management device in which the product ID and the frame ID are associated with each other and stored in the database.

5. 2. The management device according to claim 1, A management device in which the camera photographs the front nugget portion of the weld.

6. 2. The management device according to claim 1, further comprising: A management device having an appearance inspection unit that judges whether the appearance shape of the weld is good or bad.

7. A method for managing a workpiece having a weld, comprising the steps of: The information on the product is associated with a product ID and stored in a database; Photographing the welded portion of the workpiece; The nugget pattern of the welded portion photographed is image-processed; acquiring pattern data corresponding to the nugget pattern obtained by the image processing; A method for managing finished products, comprising storing the pattern data and the product ID in a database in association with each other.

8. The management method according to claim 7, Photographing the welds of a product whose product ID is unknown, acquiring comparison data corresponding to the nugget pattern by performing image processing on the photographed nugget pattern of the weld; Matching the matching data with existing pattern data stored in a database; When the verification data matches the existing pattern data, a product ID linked to the existing pattern data is acquired.

Images