Method for manufacturing metal product and metal product

Abstract

The present disclosure describes a method for manufacturing a metal product capable of improving the readability of an identification code and the metal product. The method for manufacturing a rotor laminated core (1) includes: repeatedly performing a step of irradiating a surface (2b) of a laminate (2) with a base laser beam and scanning the base laser beam along a predetermined first direction, thereby forming a base region (12) on the surface (2b) of the laminate (2); and repeatedly performing a step of irradiating a marking laser beam with a marking laser beam and scanning the marking laser beam along a predetermined second direction, thereby forming a black mark (14) formed by oxidizing the surface (2b) of the laminate (2). The second direction is different from the first direction. The combination of the base region (12) and the black mark (14) forms an identification code (10) having a predetermined pattern.

Description

[0001] This application is a divisional application filed on February 6, 2018, with application number 201880024445.X, entitled "Method for manufacturing a metal product and metal product." Priority is claimed to prior Japanese application No. JP2017-080582, filed on April 14, 2017. Technical Field

[0002] The present disclosure relates to a method for manufacturing a metal product and the metal product. Background Art

[0003] Patent Document 1 discloses a method for obtaining a metal product by forming a two-dimensional code on the surface of a metal part. The method comprises: repeatedly irradiating the surface of the metal part with a laser beam to oxidize the metal and burn circular dots corresponding to the shape of the beam on the surface, thereby forming a black mark of a predetermined pattern. As a result, a two-dimensional code consisting of a combination of black cells, which are a collection of multiple circular dots, and white cells, which are areas not irradiated with the laser beam, is formed on the surface of the metal part. The two-dimensional code has the function of an identification code used to identify the individual metal product (for example, type, manufacturing date and time, materials used, production line, etc.).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-222516 Summary of the Invention

[0007] (1) Technical issues to be resolved

[0008] Furthermore, the metal parts on which the QR codes are formed are typically produced by rolling a metal material using rollers. In this process, scratches on the roller surface are transferred to the surface of the metal part, potentially leaving fine linear marks (also known as rolling marks). Alternatively, the metal part may undergo various surface treatments before forming the identification code. These surface treatments can result in uneven gloss or a mirror finish on the metal part's surface.

[0009] In such cases, when flashlight is shone onto a metal component to read a 2D code formed on the metal surface with a camera, the light may enter the camera irregularly due to rolling marks, gloss, etc., or the light may be reflected by the metal surface. This not only reduces the readability of the 2D code, but also causes variations in readability between metal products.

[0010] Therefore, the present disclosure describes a method for manufacturing a metal product and a metal product that can improve the readability of an identification code.

[0011] (2) Technical solution

[0012] A method for manufacturing a metal product according to one aspect of the present disclosure includes: repeatedly irradiating the surface of a metal component with a base laser beam and scanning the base laser beam in a predetermined first direction, thereby forming a base region on the surface of the metal component; and repeatedly irradiating the surface of the metal component with a marking laser beam and scanning the marking laser beam in a predetermined second direction, thereby forming a black mark in a predetermined pattern by oxidizing the surface of the metal component. The second direction is different from the first direction. The combination of the base region and the marking forms an identification code in a predetermined pattern.

[0013] Another aspect of the present disclosure relates to a method for manufacturing a metal product, including the steps of repeatedly irradiating the surface of a metal part with a pulsed laser beam, i.e., a marking laser beam, with the marking laser beam scanning along a predetermined first direction to form a mark. The marking laser beam is scanned in the first direction at a feed pitch less than the spot diameter and at a predetermined arrangement pitch in the column direction. The mark is composed of a combination of a plurality of square-shaped units. The step of forming the mark includes: defining the parameters a, b, and n as

[0014] a: the length of one side of the unit;

[0015] b: Pulse diameter of the marking laser beam;

[0016] n: The number of scans of the marking laser beam per unit. In the case where the marking laser beam is irradiated to each unit so as to satisfy the formula 1,

[0017] b×n / a≧0.5···(1).

[0018] Another aspect of the present disclosure is a metal product in which an identification code having a predetermined pattern is formed on the surface of a metal component by combining a base region and a marking. The base region is configured by arranging multiple rows of laser grooves extending along a predetermined first direction. The marking is configured by arranging multiple rows of laser grooves extending along a predetermined second direction different from the first direction.

[0019] (3) Beneficial effects

[0020] According to the method for manufacturing a metal product and the metal product disclosed herein, the readability of the identification code can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a perspective view showing an example of a rotor laminated core.

[0022] Figure 2 It is along Figure 1 Cross-sectional view of line II-II.

[0023] Figure 3 This is a plan view showing an example of an identification code provided on a rotor laminated core.

[0024] Figure 4 This is a diagram showing an example of the surface profile of a laminate (punched component).

[0025] Figure 5 This is a photograph showing a partial magnification of the basement area.

[0026] Figure 6 It is a schematic diagram showing an example of a black cell.

[0027] Figure 7 This is a photograph showing a partial enlargement of the area near the boundary between the black mark and the background area.

[0028] Figure 8 This is a schematic diagram for explaining an example of the process of generating an identification code.

[0029] Figure 9 This is a diagram for explaining a method of reading an identification code.

[0030] Figure 10 (a) is a graph showing the relationship between the number of scans of a marking laser beam on a square unit with a side of 0.15 mm and the reading success rate of the identification code formed by the number of scans. Figure 10 (b) is a graph showing the relationship between the number of scans of a marking laser beam on a square unit with a side of 0.285 mm and the reading success rate of the identification code formed by the number of scans.

[0031] Figure 11 This figure shows an example of an image of an identification code captured by a camera.

[0032] Figure 12 This is a schematic diagram for explaining another example of the process of generating an identification code.

[0033] Figure 13 This is a schematic diagram for explaining another example of the process of generating an identification code.

[0034] Figure 14 This is a schematic diagram for explaining another example of the process of generating an identification code.

[0035] Figure 15 This is a schematic diagram for explaining another example of the process of generating an identification code.

[0036] Figure 16This is a schematic diagram for explaining another example of the formation process of the base region. DETAILED DESCRIPTION

[0037] An example of an embodiment of the present disclosure will be described in more detail below with reference to the accompanying drawings. In the following description, the same reference numerals are used for elements having the same elements or the same functions, and repeated descriptions are omitted.

[0038] [Structure of the rotor laminated core]

[0039] First, refer to Figure 1 and Figure 2 The structure of the rotor laminated core 1 as an example of a metal product will be described. The rotor laminated core 1 is a part of the rotor. The rotor is formed by attaching end plates and a main shaft (neither of which are shown in the figure) to the rotor laminated core 1. Figure 1 As shown, the rotor laminated core 1 includes a laminated body 2 (metal member), a caulking portion 3 , and an identification code 10 .

[0040] The laminate 2 is cylindrical. Figure 1 As shown, a through hole 2a (center hole) extending along the center axis Ax is provided in the center portion of the laminate 2. The spindle can be arranged in the through hole 2a.

[0041] The stack 2 is a stack of multiple blanking parts W. The blanking parts W are plate-shaped bodies punched into a predetermined shape from electromagnetic steel sheets (metal sheets). Since the electromagnetic steel sheets are rolled using rollers, rolling marks may occur on the surfaces of the blanking parts W. The stack 2 can be constructed by so-called rotational lamination, in which the blanking parts W are stacked while being staggered relative to each other. The angle of rotational lamination can be set to any value.

[0042] In this embodiment, adjacent blanking parts W in the stacking direction are fastened to each other by caulking portions 3. Specifically, Figure 2As shown, the rivet 3 includes a deformed portion 3a formed on the punched part W of the layer other than the bottom layer of the stack 2, and a through-hole 3b formed in the punched part W of the bottom layer of the stack 2. The deformed portion 3a is composed of a recessed portion formed on the front side of the punched part W and a convex portion formed on the back side of the punched part W. The recessed portion of the deformed portion 3a of one punched part W engages with the convex portion of the deformed portion 3a of another punched part W adjacent to the front side of the punched part W. The convex portion of the deformed portion 3a of one punched part W engages with the recessed portion of the deformed portion 3a of another punched part W adjacent to the back side of the punched part W. The convex portion of the deformed portion 3a of the punched part W adjacent to the bottom layer of the stack 2 engages with the through-hole 3b. The through-hole 3b prevents the deformed portion 3a of a subsequently formed punched part W from being fastened to the already formed stack 2 during the continuous production of the stack 2.

[0043] Instead of the rivets 3, the multiple blanking parts W may be fastened to each other by various other known methods. The multiple blanking parts W may be joined to each other using, for example, an adhesive or resin material, or may be joined to each other by welding. Alternatively, temporary rivets may be provided on the blanking parts W, and the multiple blanking parts W may be fastened by the temporary rivets to obtain a stacked body, and then the temporary rivets may be removed from the stacked body to obtain the stacked body 2. In addition, the so-called "temporary rivets" refer to rivets used to temporarily integrate the multiple blanking parts W and removed during the process of manufacturing the product (stacked body 2).

[0044] The stacked body 2 may be provided with at least one magnet insertion hole (not shown) extending along the extension direction of the central axis Ax (the stacking direction) and penetrating the stacked body. The magnet insertion hole may be filled with a resin material while a permanent magnet (not shown) is disposed therein. The resin material serves to secure the permanent magnet within the magnet insertion hole and to bond adjacent punched parts W in the vertical direction.

[0045] [Details of the identification code]

[0046] like Figure 1As shown, an identification code 10 is provided on the surface 2b (upper surface or lower surface) of the laminate 2, that is, the outer surface of the punched part W constituting the uppermost layer or the lowermost layer of the laminate 2. The identification code 10 has the function of maintaining individual information (for example, variety, manufacturing date and time, used materials, production line, etc.) for identifying the individual rotor laminated core 1 having the identification code 10. The identification code 10 is not particularly limited as long as it can maintain the individual information through a combination of light patterns and dark patterns. For example, it can be a bar code or a two-dimensional code. As a two-dimensional code, for example, it can be a QR code (registered trademark), DataMatrix, Vericode, etc. As Figure 3 As shown, the identification code 10 is composed of a base area 12 and black marks 14. The identification code 10 forms a predetermined pattern by the combination of the base area 12 and the black marks 14.

[0047] like Figure 3 As shown, the identification code 10 has a plurality of virtual units 16. The plurality of units 16 are arranged in a grid shape and correspond to the size of the identification code 10 as a whole. Figure 3 Grid-like lines that divide each unit 16 are shown in the figure, but these lines are only drawn to facilitate understanding of the invention and do not exist in the actual identification code 10. The size of the unit 16 is not particularly limited and can be various sizes depending on the required performance of the identification code 10. The shape of the unit 16 is not particularly limited and can be, for example, square, rectangular, circular, polygonal, or other indeterminate shapes. In this embodiment, the unit 16 is set to, for example, a square shape of 0.15 mm × 0.15 mm, a square shape of 0.285 mm × 0.285 mm, or the like. In this specification, the unit 16 formed with the base area 12 is referred to as a white unit 16a, and the unit 16 formed with the black mark 14 is referred to as a black unit 16b.

[0048] The base region 12 is formed by irradiating the surface 2b of the laminate 2 with a base laser beam. The size of the base region 12 is not particularly limited and can be various sizes depending on the size of the laminate 2, the type of material of the punched component W, the formation position of the identification code 10, and the like. The shape of the base region 12 is not particularly limited and can be, for example, square, rectangular, circular, polygonal, or other indeterminate shapes. In this embodiment, the base region 12 is, for example, a 5 mm x 5 mm square.

[0049] As the base laser beam for forming the base region 12, for example, a YAG laser, a YVO4 laser, a fiber laser, etc. can be cited. The base laser beam can be a continuous wave (CW) laser or a pulsed laser. The beam diameter (the diameter of the light before the beam reaches the irradiation object), the spot diameter (the diameter of the light on the surface of the irradiation object when the base laser beam irradiates the irradiation object), and the output of the base laser beam are not particularly limited, and can be various sizes depending on the type of beam, the type of material of the punched part W, the thickness of the punched part W, etc. In addition, since the molten state formed by the beam will be different depending on the type of material of the irradiation object irradiated by the base laser beam, the spot diameter may change even when the beam diameter is the same.

[0050] Since the surface 2b of the laminated body 2 (punched part W) is processed with the laser beam through the substrate, Figure 4 As shown, the base region 12 has a very high flatness. Figure 4 As shown, the surface of the punched part W having rolling marks has irregularities with a height of about several μm to several tens of μm, but the height of the irregularities on the surface of the base region 12 is about 1 μm or less.

[0051] The base region 12 is formed by repeatedly performing a plurality of operations while irradiating the surface of the laminate 2 (punched part W) with a base laser beam and directing the base laser beam in a predetermined direction A (refer to FIG. Figure 8 That is, Figure 5 As shown, the base region 12 is configured to have multiple rows of laser grooves extending in the direction A (scanning direction). As an example, Figure 5 The state of the laser groove when pulsed laser light is used as the base laser beam is shown. Figure 5 A laser slot in Figure 5 The left side of the blanking part W is connected to the right side by a plurality of pulse traces (traces produced by irradiating the surface of the blanking part W with a pulsed base laser beam). Figure 5 The laser groove is formed by using a laser beam from the substrate to Figure 5 It is formed by scanning from the left side to the right side.

[0052] In the direction of the scanning rows of the base laser beam (the direction of the laser grooves), i.e., the row direction, the pitch of the base laser beam (the pitch of the laser grooves) may be less than or equal to the spot diameter of the base laser beam. That is, adjacent laser grooves in the row direction at least partially overlap. If the base laser beam is a pulsed laser, the pulse traces may be arranged in the scanning direction of the base laser beam at a pitch less than or equal to the spot diameter.

[0053] In this embodiment, a black mark 14 is formed by irradiating the base area 12 with a marking laser beam. The black mark 14 is formed by oxidizing the punched part W with the marking laser beam and becoming black. The black mark 14 has a predetermined pattern and constitutes the identification code 10 together with the surrounding base area 12. Specifically, Figure 3 As shown, the black mark 14 is an aggregate of a plurality of black cells 16 b formed by irradiating the cells 16 with a marking laser beam to fill the cells 16 with black.

[0054] As the marking laser beam for forming the black mark 14, for example, YAG laser, YVO4 laser, fiber laser, etc. can be cited. The marking laser beam can be a continuous wave oscillation laser or a pulsed oscillation laser. The beam diameter (the diameter of the light before the beam reaches the irradiation object), the spot diameter (the diameter of the light on the surface of the irradiation object when the marking laser beam is irradiated to the irradiation object) and the output of the marking laser beam are not particularly limited, and can be various sizes depending on the type of beam, the type of material of the punched part W, the thickness of the punched part W, etc. However, the output of the marking laser beam is greater than the output of the substrate laser beam, for example, it can be more than 10 times the output of the substrate laser beam. In addition, since the molten state formed by the beam will be different depending on the type of material of the irradiation object irradiated by the marking laser beam, the spot diameter may change even when the beam diameter is the same.

[0055] By repeatedly performing the operation of irradiating the base region 12 with a marking laser beam while directing the marking laser beam in a predetermined direction B (see Figure 8 The black unit 16b is formed by scanning (b). Figure 6 and Figure 7 As shown, the base region 12 is configured to have multiple rows of laser slots extending in the direction B (scanning direction). As an example, Figure 6 and Figure 7 Both show the state of the laser groove when pulsed laser light is used as the marking laser beam. Figure 6 and Figure 7 A laser slot in Figure 6 and Figure 7 The upper side of the base region 12 is connected to the lower side by a plurality of pulse marks (marks produced by irradiating the surface of the base region 12 with a pulsed laser beam). Figure 6 and Figure 7 The laser slots are created by marking with a laser beam from Figure 6 and Figure 7 It is formed by scanning from the upper side toward the lower side.

[0056] The arrangement pitch of the marking laser beam (the arrangement pitch of the laser grooves) may be set as a predetermined interval in the row direction, which is the direction in which the scanning row of the marking laser beam is arranged (the direction in which the laser grooves are arranged). For example, Figure 6 As shown in (a), the arrangement pitch is roughly the same as the spot diameter of the marking laser beam, or it can be, Figure 6 As shown in (b), it is larger than the spot diameter of the marking laser beam, and can also be, as shown in Figure 6 As shown in (c), it is smaller than the spot diameter of the marking laser beam. That is, the laser grooves adjacent to each other in the column direction can be adjacent to each other (refer to Figure 6 (a)), can also be separated (refer to Figure 6 (b)), may also at least partially overlap with each other (cf. Figure 6 (c)). When the marking laser beam is a pulsed laser beam, the pulse marks may be arranged at a feed pitch that is smaller than the spot diameter in the scanning direction of the marking laser beam.

[0057] The scanning direction of the marking laser beam may be different from the scanning direction of the substrate laser beam. That is, the scanning direction of the marking laser beam and the scanning direction of the substrate laser beam may be in opposite directions or may cross each other. Figure 7 In the example shown, the scanning direction of the marking laser beam is orthogonal to the scanning direction of the substrate laser beam.

[0058] [How to create an identification code]

[0059] Next, a method for forming the identification code 10 on the laminated body 2, that is, a method for manufacturing the rotor laminated core 1, will be described. First, the laminated body 2 is formed by stacking the laminated body 2 while punching out parts W from electromagnetic steel sheets (worked sheets), which are strip-shaped metal sheets.

[0060] Then, if Figure 8 As shown in (a), a base laser beam is used to form a base region 12 on the surface 2b of the laminate 2 (the outer surface of the punched component W constituting the uppermost or lowermost layer of the laminate 2). At this time, the base region 12 is formed by repeatedly scanning the base laser beam along a predetermined direction A in multiple rows. In this embodiment, the base laser beam is irradiated over the entire area of the identification code 10 where the predetermined area is to be formed. That is, in this embodiment, the base laser beam is also irradiated over the predetermined cells 16 where the black marks 14 are to be formed.

[0061] Then, if Figure 8As shown in (b), cells 16 to be black cells 16b are identified among the plurality of cells 16 according to the predetermined identification code 10. Next, a marking laser beam is used to form black marks 14 on the base region 12. Specifically, black marks 14 are formed by repeatedly scanning the identified cells 16 in a predetermined direction B, which is different from direction A, over multiple columns.

[0062] When forming the black mark 14, the parameters a, b, and n may be positioned as a: the length of one side of the unit 16;

[0063] b: Pulse diameter of the marking laser beam;

[0064] n: The number of scanning times of the marking laser beam per unit 16 , the marking laser beam is irradiated to each determined unit 16 so as to satisfy the formula 2.

[0065] b×n / a≧0.5···(2).

[0066] The condition satisfying equation 2 means that the irradiation area a×b×n of the marking laser beam is equal to the area a of the cell 16. 2 The ratio (a×b×n / a 2 ) is 0.5 or more. Therefore, when the formula 2 is satisfied, the filling rate of each black cell 16b is 50% or more (for example, the filling rate is about 57%). Figure 6 (b)). Therefore, the filling rate of each black cell 16b is relatively large, thereby further improving the contrast between the black mark 14 and the base area 12. Therefore, the readability of the identification code 10 can be further improved.

[0067] When forming the black mark 14 , the marking laser beam may be irradiated onto each of the determined cells 16 so that the parameters a, b, and n satisfy Expression 3, Expression 4, or Expression 5.

[0068] b×n / a≧1···(3)

[0069] b×n / a≧2···(4)

[0070] b×n / a≧3···(5)

[0071] When the expression 3 is satisfied, the filling rate of each black cell 16b reaches 100% or more (refer to FIG. 1 for an example of a filling rate of about 100%). Figure 6 (a)). When equation 4 is satisfied, the coating rate of each black cell 16b reaches 200% or more. When equation 5 is satisfied, the coating rate of each black cell 16b reaches 300% or more (refer to the example of a coating rate of 300%). Figure 6In these cases, since the fill rate of each black cell 16b is sufficiently large, the contrast between the black mark 14 and the base area 12 is greatly improved. Therefore, the readability of the identification code 10 can be greatly improved.

[0072] The length a is determined based on, for example, the size of the identification code 10 (base region 12) and the data capacity held by the identification code 10. The pulse diameter b is determined based on the output of the marking laser beam and the material of the irradiation object (laminated body 2).

[0073] When the identification code 10 is formed on the surface 2 b of the laminated body 2 through the above steps, the rotor laminated core 1 is completed.

[0074] [How to read the identification code]

[0075] Next, the method of reading the identification code 10 is described. For example, Figure 9 The reader 20 shown reads the identification code 10. The reader 20 includes a conveyor 22, a camera 24 for reading, and a controller 26.

[0076] The conveyor 22 operates based on instructions from the controller 26 and has the function of conveying the loaded rotor laminated core 1 in a predetermined direction. A camera 24 is located above the conveyor 22. Based on instructions from the controller 26, the camera 24 captures the identification code 10 when the rotor laminated core 1 conveyed by the conveyor 22 passes below the camera 24. The controller 26 processes the image data captured by the camera 24 and reads the identification code 10. If the controller 26 determines that the identification code 10 has not been read, the controller 26 causes the camera 24 to repeatedly capture the identification code 10 as long as the rotor laminated core 1 is within the camera 24's imaging range.

[0077] Here, a pulsed laser beam (i.e., a marking laser beam) with a spot diameter of 30 μm was irradiated onto square cells 16 to form black marks 14 within base region 12. The resulting identification code 10 was then read from a predetermined direction (but not directly above) using camera 24. This experiment measured the reading success rate while varying the size of cell 16 and the number of scans. In this specification, the term "reading success rate" refers to the percentage of successful reads by camera 24 when the identification code 10 was read 50 times using camera 24.

[0078] exist Figure 10(a) shows the results when one side of unit 16 is set to 0.15 mm and the number of scans of the marking laser beam is varied between 4 and 32 (but only an even number after 16). When the number of scans is 4 (the coating rate is 80%), the reading success rate is 35%. When the number of scans is 5 (the coating rate is 100%), the reading success rate is 37%. When the number of scans is 6 (the coating rate is 120%), the reading success rate is 39%. When the number of scans is 7 (the coating rate is 140%), the reading success rate is 42%. When the number of scans is 8 (the coating rate is 160%), the reading success rate is 45%. When the number of scans is 9 (the coating rate is 180%), the reading success rate is 72%. When the number of scans is more than 10 (the coating rate is more than 200%), the reading success rate is 100%.

[0079] exist Figure 10 (b) shows the results when one side of unit 16 is set to 0.285 mm and the number of scans of the marking laser beam is varied between 6 and 32 (but only an even number after 16). When the number of scans is 6 (the coating rate is 63%), the reading success rate is 33%. When the number of scans is 7 (the coating rate is 73.7%), the reading success rate is 35%. When the number of scans is 8 (the coating rate is 84.2%), the reading success rate is 42%. When the number of scans is 9 (the coating rate is 94.7%), the reading success rate is 44%. When the number of scans is 10 (the coating rate is 105.3%), the reading success rate is 44%. When the number of scans is 11 (the coating rate is 115.8%), the reading success rate is 43%. When the number of scans is 12 (the coating rate is 126.3%), the reading success rate is 56%. When the number of scans is 13 (the coverage rate is 136.8%), the read success rate is 56%. When the number of scans is 14 (the coverage rate is 147.4%), the read success rate is 60%. When the number of scans is 15 (the coverage rate is 157.9%), the read success rate is 57%. When the number of scans is 16 (the coverage rate is 168.4%), the read success rate is 62%. When the number of scans is 18 (the coverage rate is 189.4%), the read success rate is 80%. When the number of scans is 20 or more (the coverage rate is 210.5% or more), the read success rate is 100%.

[0080] According to the above test results, when the full coverage rate is 50% or more, it is confirmed with a probability of at least 30% that the reading of the identification code 10 is successful.

[0081] [effect]

[0082] In the present embodiment described above, the base region 12 is first formed on the surface 2b of the laminate 2, and then the black mark 14 is formed within the base region 12. This results in a rotor laminated core 1 having an identification code 10 formed on the surface 2b of the laminate 2, formed by the combination of the black mark 14 and the base region 12. Consequently, the black mark 14 exists within the uniform base region 12 on the surface 2b. This improves the contrast between the black mark 14 and the base region 12. Consequently, the readability of the identification code 10 can be improved.

[0083] In this embodiment, the base region 12 is formed by repeatedly scanning the base laser beam along direction A in multiple columns, and the black marks 14 are formed by repeatedly scanning the marking laser beam along direction B, which is different from direction A, in multiple columns. That is, the laser grooves forming the base region 12 extend along the same direction A in all columns. Therefore, it is easier to reflect light incident on the base region 12 in approximately the same direction. Similarly, the laser grooves forming the black marks 14 extend along the same direction B in all columns. Therefore, it is easier to reflect light incident on the black marks 14 in approximately the same direction. This further improves the contrast between the black marks 14 and the base region 12. As a result, the readability of the identification code 10 can be further improved.

[0084] In this embodiment, the scanning direction of the marking laser beam, i.e., direction B, intersects (is orthogonal to) the scanning direction of the substrate laser beam, i.e., direction A. Therefore, the direction of the reflected light from the substrate area 12 is different from the direction of the reflected light from the black mark 14. Thus, the contrast between the black mark 14 and the substrate area 12 is further improved. As a result, the readability of the identification code 10 can be further improved. In addition, if the scanning direction of the marking laser beam, i.e., direction B, is the same as the scanning direction of the substrate laser beam, i.e., direction A, it is possible as shown in FIG. Figure 11 As shown, the contrast is reduced and the captured image of the identification code 10 is unclear.

[0085] According to the present invention, since the contrast between the black mark 14 and its surroundings is improved, the camera 24 can capture the identification code 10 not only from a position facing the identification code 10 but also from an oblique direction. In particular, the rotor laminated core 1 may change state due to, for example, insertion of a main shaft into the through-hole 2a in a subsequent step, which tends to limit the direction from which the camera 24 can capture the identification code 10. However, according to the present invention, the identification code 10 can be read from a variety of directions.

[0086] [Modification]

[0087] While the embodiments of the present disclosure have been described in detail above, various modifications may be made to the above embodiments within the scope of the gist of the present invention.

[0088] (1) The identification code 10 may be formed from a combination of the base region 12 and the black markings 14. Specifically, as in the above-described embodiment, the black markings 14 may be formed on the base region 12. Alternatively, the identification code 10 may be formed so that the base region 12 and the black markings 14 do not overlap. However, a certain degree of overlap between the base region 12 and the black markings 14 due to irradiation errors between the base laser beam and the marking laser beam is permitted.

[0089] Specifically, first, Figure 12 As shown in (a), the base laser beam is repeatedly irradiated on only the predetermined cells 16 forming the base region 12 in the identification code 10 and scanned along the direction A, thereby obtaining only white cells 16a. Figure 12 As shown in (b), the marking laser beam is repeatedly irradiated on only the predetermined cells 16 in the identification code 10 where the black mark 14 is to be formed, and the marking laser beam is scanned in direction B, thereby obtaining only the black cells 16b. In this manner, the base region 12 and the black mark 14 are formed without substantially overlapping each other.

[0090] Or, first, as Figure 13 As shown in (a), the marking laser beam is repeatedly irradiated on only the predetermined unit 16 forming the black mark 14 in the identification code 10 and the marking laser beam is scanned along the direction B, thereby obtaining only the black unit 16b. Figure 13 As shown in (b), the base laser beam is repeatedly irradiated on only the predetermined cells 16 forming the base region 12 in the identification code 10, and the base laser beam is scanned in direction A, thereby obtaining only white cells 16a. In this manner, the base region 12 and the black mark 14 are formed without substantially overlapping each other.

[0091] (2) The scanning direction of the marking laser beam, direction B, may not intersect with the scanning direction of the substrate laser beam, direction A. For example, direction B and direction A may be substantially the same direction or substantially opposite directions.

[0092] (3) The scanning direction of the base laser beam when forming the base region 12 is not limited to the direction A, but may be in various directions, for example, it may be in a serpentine manner, or in a direction in which the outgoing and returning directions are opposite (see Figure 14 ), or it can be scroll-shaped (see Figure 15When the scanning direction of the substrate laser beam is opposite to that of the outgoing path and the returning path, the substrate area 12 is formed by scanning the substrate laser beam in a reciprocating manner in the direction A1 and the direction A2 opposite thereto (see Figure 14 (a)). Then, the marking laser beam is scanned along a direction B different from the directions A1 and A2 to form a black mark 14 (see Figure 14 (b)). When the scanning direction of the substrate laser beam is spiral, the substrate region 12 is formed by repeatedly scanning the substrate laser beam along direction A1, scanning the substrate laser beam from its end point along direction A2 orthogonal to direction A1, scanning the substrate laser beam from its end point along direction A3 orthogonal to direction A2, and scanning the substrate laser beam from its end point along direction A4 orthogonal to direction A3 (see Figure 15 (a)). Then, the marking laser beam is scanned along a direction B different from the directions A1 and A3 to form a black mark 14 (see Figure 15 (b)). Similarly, the scanning direction of the marking laser beam when forming the black mark 14 is not limited to the direction B, but can be various directions, for example, it can be a serpentine shape, it can be in opposite directions on the outgoing and return paths, or it can be a spiral shape.

[0093] (4) The arrangement pitch of the laser slots within the black cell 16b may be constant or non-constant. That is, the spacing between adjacent laser slots may be equal or non-equal. If the spacing between adjacent laser slots is not equal, the laser slots may be distributed evenly within the cell 16 to a certain extent.

[0094] (5) The black mark 14 may be formed directly on the surface 2 b of the laminate 2 without forming the base region 12 .

[0095] (6) As long as the reading success rate of the identification code 10 exceeds 0%, the filling rate in each black cell 16b may be less than 50%.

[0096] (7) When permanent magnets are provided within the laminate 2, metal end plates, such as those made of stainless steel, may be provided at each end face of the laminate 2 to prevent demagnetization of the magnets. The identification code 10 may be provided on each of these end plates. The surface treatment of the metal end plates may sometimes cause the metal end plates to have an uneven surface gloss or a mirror finish. However, even in such cases, the present invention can improve the contrast between the black mark 14 and its surroundings, thereby improving the readability of the identification code 10.

[0097] (8) When the identification code 10 is photographed by the camera 24 , the photographing conditions such as lighting may be appropriately changed to obtain a clear photographic image of the identification code 10 .

[0098] (9) The identification code 10 may be formed by a combination of other methods other than the combination of white cells 16a and black cells 16b. In other words, as long as the contrast can be improved, the identification code 10 may be formed by combining various colors other than white and black. For example, the identification code 10 may be a hierarchical two-dimensional code (a two-dimensional shape code formed by multi-leveling color information). Examples of hierarchical two-dimensional codes include PM codes (registered trademarks).

[0099] (10) The base region 12 can be formed as follows. First, a base laser beam is used to perform preliminary processing (rough processing) on a predetermined area of the surface 2b of the laminate 2 (the outer surface of the punched part W constituting the uppermost layer or the lowermost layer of the laminate 2). Specifically, the base laser beam is repeatedly irradiated onto the surface 2b with a first output in multiple rows, and the base laser beam is directed in a predetermined direction A (refer to FIG. Figure 8 (a)) is scanned. Thus, a preliminary area (not shown) is formed on the surface 2b. The preliminary area becomes a state where the rolling marks of the surface Wa are roughly uniform. For example, by the preliminary treatment, the height of the rolling marks caused by the rolling marks is a few μm to several tens of μm (refer to Figure 16 The dotted line of (a) becomes a concave-convex with a height of less than 5 μm (refer to Figure 16 (a) is the solid line).

[0100] Next, the preparation area is formally processed (finished) using a base laser beam. Specifically, the base laser beam is repeatedly irradiated to the preparation area with a second output lower than the first output in multiple rows, and the base laser beam is directed along a predetermined direction A (refer to Figure 8 The second output can be, for example, less than 1 / 2 of the first output, less than 1 / 3 of the first output, or less than 1 / 4 of the first output. Thus, a base region 12 is formed on the surface 2b. The base region 12 becomes a state where the surface of the preparatory region is more flattened. For example, by formal processing, the height of the preparatory region is made to be less than 5 μm (refer to Figure 16 The dotted line of (b) becomes a concave-convex with a height of less than 1 μm (refer to Figure 16 By forming the black mark 14 on the base region 12 thus formed, the contrast between the black mark 14 and the base region 12 is further improved. As a result, the readability of the identification code 10 can be greatly improved.

[0101] (11) The present invention can be applied not only to the rotor laminated core 1 but also to the stator laminated core and various other metal products.

[0102] [extract]

[0103] Example 1. A method for manufacturing a metal product according to one example of the present disclosure includes: repeatedly irradiating the surface of a metal component with a base laser beam and scanning the base laser beam in a predetermined first direction, thereby forming a base region on the surface of the metal component; and repeatedly irradiating the surface of the metal component with a marking laser beam and scanning the marking laser beam in a predetermined second direction, thereby forming a mark. The second direction is different from the first direction. The combination of the base region and the mark forms an identification code having a predetermined pattern.

[0104] According to Example 1, the following steps are performed: forming a base region on the surface of a metal component; and forming a mark on the surface of the metal component. This results in a metal product having an identification code formed on the surface of the metal component, consisting of a combination of the mark and the base region. Consequently, the mark is present within an area surrounded by the uniform base region. This improves the contrast between the mark and the base region. Consequently, the readability of the identification code can be enhanced.

[0105] According to Example 1, the base region is formed by repeatedly scanning the base with a laser beam along a first direction in multiple columns, and the marking is formed by repeatedly scanning the marking laser beam along a second direction in multiple columns. That is, the laser grooves constituting the base region extend along the same first direction in any column. Therefore, it is easy to cause light incident on the base region to be reflected in approximately the same direction. Similarly, the laser grooves constituting the marking extend along the same second direction in any column. Therefore, it is easy to cause light incident on the marking to be reflected in approximately the same direction. This further improves the contrast between the marking and the base region. As a result, the readability of the identification code can be further improved.

[0106] According to Example 1, the second scanning direction of the marking laser beam is different from the first scanning direction of the substrate laser beam. Therefore, the direction of light reflected from the substrate area is different from the direction of light reflected from the marking. This further improves the contrast between the marking and the substrate area. Consequently, the readability of the identification code can be further enhanced.

[0107] Example 2. In the method of Example 1, the step of forming a mark can form a mark by irradiating a marking laser beam on the substrate area.

[0108] Example 3. In the method of Example 1, the base region and the mark can be formed in regions that do not overlap with each other.

[0109] Example 4. In any of the methods of Examples 1 to 3, the second direction may intersect the first direction. In this case, the contrast between the mark and the base area is further improved. As a result, the readability of the identification code can be further improved.

[0110] Example 5. In any of the methods of Examples 1 to 4, the substrate laser beam and the marking laser beam may be pulsed lasers respectively, the substrate laser beam scans in the first direction with a feed pitch less than the spot diameter and in the column direction with an arrangement pitch less than the spot diameter, and the marking laser beam scans in the second direction with a feed pitch less than the spot diameter and in the column direction with a prescribed arrangement pitch.

[0111] Example 6. In the method of Example 5, the mark may be composed of a plurality of square-shaped units, and the step of forming the mark includes: defining the parameters a, b, and n as

[0112] a: the length of one side of the unit;

[0113] b: Pulse diameter of the marking laser beam;

[0114] n: The number of scans of the marking laser beam per unit. In the case where the marking laser beam is irradiated to each unit so as to satisfy Equation 6,

[0115] b×n / a≧0.5···(6).

[0116] In this case, the ratio of the total area irradiated by the second laser beam to the area of a cell constituting the mark, i.e., the second laser beam's coverage rate per cell (hereinafter referred to as the "coverage rate"), is 50% or greater. This results in a relatively high coverage rate for each cell, further enhancing the contrast between the mark and the base area. Consequently, the readability of the identification code can be further improved.

[0117] Example 7. In the method of Example 6, the step of forming a mark may include: irradiating each unit with a marking laser beam in a manner satisfying Formula 7,

[0118] b×n / a≧1···(7).

[0119] In this case, the filling rate is 100% or more. Therefore, the filling rate of each cell is sufficiently large, thereby greatly improving the contrast between the mark and the base area. As a result, the readability of the identification code can be greatly improved.

[0120] Example 8. In any of the methods of Examples 1 to 7, the mark may be a black mark formed by oxidizing the surface of the metal part using a marking laser beam.

[0121] Example 9. In any of the methods of Examples 1 to 8, the step of forming the base area may include: repeatedly executing multiple rows of irradiating the surface of the metal part with a base laser beam at a first output and scanning the base laser beam along a first direction; and repeatedly executing multiple rows of irradiating the area irradiated with the base laser beam at the first output with a second output lower than the first output and scanning the base laser beam along the first direction. In this case, when forming the base area, a laser with a higher output is first irradiated. Therefore, the rolling marks on the surface of the metal part are roughly uniform (rough processing). Thereafter, a laser with a lower output is irradiated to the area irradiated with the laser with a higher output. Therefore, the roughly uniform surface unevenness of the metal part is further flattened (finishing). Therefore, by forming a mark on the base area formed in this way, the contrast between the mark and the base area is further improved. As a result, the readability of the identification code can be greatly improved.

[0122] Example 10. Another example of a method for manufacturing a metal product disclosed herein includes: repeatedly irradiating a surface of a metal part with a marking laser beam as a pulsed laser and scanning the marking laser beam along a predetermined first direction to form a mark. The marking laser beam is scanned in the first direction at a feed pitch less than the spot diameter and at a predetermined arrangement pitch in the column direction. The mark is composed of a plurality of square-shaped units. The step of forming the mark includes: defining parameters a, b, and n as

[0123] a: the length of one side of the unit;

[0124] b: Pulse diameter of the marking laser beam;

[0125] n: The number of scans of the marking laser beam per unit. In the case where the marking laser beam is irradiated to each unit so as to satisfy Formula 8,

[0126] b×n / a≧0.5···(8).

[0127] According to Example 10, the marking laser beam is irradiated onto each cell in a manner that satisfies Equation 8. Consequently, the filling rate is 50% or higher. Consequently, the filling rate of each cell is relatively high, further improving the contrast between the marking and the surrounding area. As a result, the readability of the identification code can be further improved.

[0128] Example 11. In the method of Example 10, the step of forming a mark may include: irradiating each unit with a marking laser beam in a manner satisfying Formula 9,

[0129] b×n / a≧1···(9).

[0130] In this case, the same effects as those in Example 5 can be obtained.

[0131] Example 12. The method of Example 10 or Example 11 may further include, before the step of forming the marking, the step of repeatedly irradiating the surface of the metal component with a base laser beam and scanning the base laser beam along a predetermined second direction in a plurality of rows, thereby forming a base region on the surface of the metal component, wherein the base region and the marking are combined to form an identification code having a predetermined pattern, and the step of forming the marking includes irradiating the base region with the marking laser beam. In this case, the same effects as those of Example 1 can be achieved.

[0132] Example 13. The method of Example 10 or Example 11 may further include the step of repeatedly irradiating the surface of the metal component with a base laser beam and scanning the base laser beam along a predetermined second direction in multiple rows, thereby forming a base region on the surface of the metal component, wherein the base region and the marking are combined to form an identification code having a predetermined pattern, and the base region and the marking are formed in non-overlapping areas. In this case, the same effects as in Example 1 can be achieved.

[0133] Example 14. In the method described in Example 12 or Example 13, the first direction and the second direction may intersect with each other. In this case, the same effects as those of Example 4 can be obtained.

[0134] Example 15. In any of the methods of Examples 12 to 14, the substrate laser beam may be a pulsed laser, and the substrate laser beam may be scanned with a feed pitch smaller than the spot diameter in the second direction and with an arrangement pitch smaller than the spot diameter in the column direction.

[0135] Example 16. In any of the methods of Examples 12 to 15, the step of forming the base region may include: repeatedly performing multiple rows of irradiating the surface of the metal component with a base laser beam at a first output and scanning the base laser beam along a first direction; and repeatedly performing multiple rows of irradiating the region irradiated with the base laser beam at a second output lower than the first output and scanning the base laser beam along the first direction. In this case, the same effects as those of Example 9 can be achieved.

[0136] Example 17. In any of the methods of Examples 10 to 16, the mark may be a black mark formed by oxidizing the surface of the metal part using a marking laser beam.

[0137] Example 18. Another example of the present disclosure is a metal product in which an identification code having a predetermined pattern is formed on the surface of a metal component by combining a base region and a marking. The base region is configured by arranging multiple rows of laser grooves extending along a predetermined first direction, and the marking is configured by arranging multiple rows of laser grooves extending along a predetermined second direction different from the first direction. Example 18 achieves the same effects as Example 1.

[0138] Example 19. In the metal product of Example 18, the second direction may intersect the first direction. In this case, the same effects as those of Example 2 can be obtained.

[0139] Example 20. In the metal product of Example 19, the base area may be configured such that the pulse traces are arranged at a feed pitch less than the spot diameter in the first direction, and the pulse traces are arranged at an arrangement pitch less than the spot diameter in the column direction, and the marking is configured such that the pulse traces are arranged at a feed pitch less than the spot diameter in the second direction, and the pulse traces are arranged at a prescribed arrangement pitch in the column direction.

[0140] Example 21. In any of the metal products of Examples 18 to 20, the mark may be a black mark formed by oxidizing the surface of the metal part.

[0141] Description of Reference Numerals

[0142] 1- rotor laminated core (metal product); 2- laminated body (metal part); 2b- surface; 10- identification code; 12- base area; 14- black mark; 16- unit; 16a- white unit; 16b- black unit; 20- reading device; 24- camera; 26- controller; W- blanking part (metal part).

Claims

1. A metal product having a marking formed on the surface of a metal part and consisting of a combination of a plurality of square units. The marking structure comprises: a plurality of rows of laser grooves extending along a first direction, pulse marks arranged in the first direction at a feed pitch smaller than the spot diameter, and pulse marks arranged in the row direction at a predetermined arrangement pitch, By combining the base region formed in the region not overlapping with the mark on the surface of the metal component and the mark, an identification code having a predetermined pattern is formed on the surface of the metal component. The identification code is a light and dark pattern composed of a combination of light and dark patterns to retain the individual information of the metal product. The base region is configured to have multiple rows of other laser grooves extending along a predetermined second direction. The surface of the base region has a higher flatness than the surface of the metal component, Define the parameters a, b, and n as a: the length of one side of the unit; b: diameter of the pulse trace; n: the number of the laser grooves per unit, Formula 1 is satisfied, and among the plurality of laser grooves constituting the mark, at least one pair of laser grooves adjacent in the column direction do not overlap with each other, 1>b×n / a≥0.5···(1).

2. The metal product according to claim 1, characterized in that The intervals between the adjacent laser grooves in the column direction are substantially equal.

3. A method for manufacturing a metal product, comprising: Repeating the steps of irradiating the surface of the metal part with a pulsed laser beam, i.e., a marking laser beam, and scanning the marking laser beam in a predetermined first direction to form a mark, The marking laser beam is scanned in the first direction at a feed pitch smaller than the spot diameter and in the column direction at a predetermined arrangement pitch. The mark is composed of a combination of multiple square-shaped units. By combining the base region formed in the region not overlapping with the mark on the surface of the metal component and the mark, an identification code having a predetermined pattern is formed on the surface of the metal component. The identification code is a light and dark pattern composed of a combination of light and dark patterns to retain the individual information of the metal product. The base region is configured to have multiple rows of other laser grooves extending along a predetermined second direction. The surface of the base region has a higher flatness than the surface of the metal component, The steps of forming the mark include: defining parameters a, b, and n as a: the length of one side of the unit; b: the pulse diameter of the marking laser beam; n: number of scans of the marking laser beam per unit, the marking laser beam is irradiated onto each unit in such a manner that Formula 2 is satisfied and at least one pair of adjacent laser grooves in the column direction among the plurality of laser grooves constituting the mark do not overlap each other. 1>b×n / a≥0.5 ··· (2)。 4. The method according to claim 3, characterized in that The intervals between the adjacent laser grooves in the column direction are substantially equal.

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