Pretreatment apparatus and pretreatment method for straightening annealing of annular substrates

Abstract

To provide a pretreatment device and a pretreatment method of corrective annealing of an annular substrate, which can continuously perform inspection without providing a preparation process in advance before corrective annealing of the annular substrate or stopping conveyance means during the inspection, and efficiently and accurately detect a defect of the annular substrate punched from a rolled metal plate without providing a plurality of light sources which radiate from different angles or performing correction processing.SOLUTION: A pretreatment device of corrective annealing of an annular substrate comprises: an adjustment portion that adjusts rolling marks of the annular substrate so as to align the rolling marks of the annular substrate to be conveyed in a fixed direction; a first defect inspection portion that detects a defect on a surface of the annular substrate; a second defect inspection portion that has a second illumination device for irradiating the annular substrate, which has an upper surface side held by a substrate holding device, with light from below and a second line camera, and detects a defect on a rear surface of the annular substrate; and a stacking device that stacks the annular substrate which has been inspected.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pretreatment apparatus and method for a circular substrate before annealing correction, which inspects defects such as flaws existing on the surface of the substrate before annealing correction of a circular substrate punched out from a rolled metal plate.

Background Art

[0002] [[ID=I2]]Disk substrates used in information storage devices such as hard disk drive devices are generally made of aluminum. In the manufacture of disk substrates, an aluminum alloy is rolled, the rolled aluminum plate is punched into a circular shape to form a disk blank (hereinafter also referred to as an aluminum substrate), the disk blank is annealed under pressure to planarize it, and mirror finishing by grinding is performed to form a ground substrate. Thereafter, nickel-phosphorus plating is applied to the surface of this ground substrate, mirror finishing by polishing is performed, and then a magnetic film is formed thereon by sputtering.

[0003] At that time, if there are defects such as flaws and rust on the surface of the aluminum substrate, they cannot be removed even by the polishing operation after annealing correction, and may become defective products. In addition, foreign matter such as dust on the surface of the aluminum substrate may cause indentation flaws when annealed under pressure.

[0004] Currently, from the perspective of resource depletion, recycling of various things is progressing, and recycling of metals that are consumed in large quantities has also been carried out for a long time. Therefore, in order to achieve efficient reuse from aluminum substrate to aluminum substrate, it is important to reliably select and exclude defective aluminum substrates before shipment. Therefore, before annealing correction of the aluminum substrate, the presence or absence of defects consisting of flaws and foreign matter on the surface of the aluminum substrate may be inspected.

[0005] In general, optical inspection equipment is used to inspect the surface of aluminum substrates. The surface of the disk substrate, which has been transported to the inspection equipment, is illuminated by a lighting device, and an image of the aluminum substrate surface is captured by an imaging device to determine whether or not there are defects.

[0006] However, the surface of the aluminum substrates transported to the inspection device has minute, streaky irregularities called "rolling marks" formed in one direction during the rolling of the aluminum alloy, which affect the reflection of the illumination light. Since these rolling marks are not always aligned in a consistent direction when the substrates are transported to the inspection device, the illumination light is scattered and reflected depending on the direction of the rolling marks, resulting in insufficient contrast and making it difficult to accurately identify defects on the surface of the aluminum substrates.

[0007] To address these problems, for example, Patent Document 1 proposes a method for correcting laminated blanks, characterized by rotating the blank mounting table to align the rolling marks on the surface of each blank material in a consistent direction before performing corrective annealing on the blank blank material for magnetic disks, which is obtained by punching out metal strip material after rolling, and then stacking them one by one in a state where the rolling marks are aligned.

[0008] Furthermore, Patent Document 2 proposes a method for inspecting the position of a compound coating on a can lid, which involves changing the illumination direction that lights up the shoulder-side boundary of the compound applied to the curled portion of the can lid in accordance with the change in the rolling direction of the can lid due to the rotation of the turntable, thereby equalizing the brightness of the portion being measured and taking an image. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2001-148119 [Patent Document 2] Japanese Patent Application Publication No. 63-151803 [Overview of the project] [Problems that the invention aims to solve]

[0010] However, while Patent Document 1 describes a process for laminating blanks with aligned rolling marks beforehand, which allows for corrective annealing of aluminum substrates with aligned rolling marks, it does not describe or suggest that inspection problems can be resolved by aligning the rolling marks immediately before inspecting the aluminum substrates. Furthermore, in Patent Document 1, since no inspection is performed before corrective annealing, foreign matter trapped between the laminated aluminum substrates may cause indentation scratches on the surface of the aluminum substrates during corrective annealing, potentially leading to a decrease in yield.

[0011] Furthermore, Patent Document 2 states that in order to perform high-precision inspections, it is necessary to move the lighting device or increase the number of lighting devices in order to appropriately change the direction of illumination by the lighting device, which makes it difficult to perform high-precision inspections.

[0012] The present invention has been made in view of the above circumstances, and aims to provide a pre-processing apparatus and pre-processing method for corrective annealing of an annular substrate that allows for continuous inspection without providing prior preparation steps or stopping the transport means during inspection, and that can efficiently and accurately detect defects in an annular substrate punched out from a rolled metal sheet without providing multiple light sources irradiating from different angles or performing correction processing. [Means for solving the problem]

[0013] The above object of the present invention is achieved by the configuration of the pretreatment apparatus for straightening annealing of an annular substrate [1]. [1] A pretreatment device for straightening annular substrates for inspecting defects present on the surface of annular substrates before straightening annealing, An adjustment unit that detects the rolling marks of the annular substrate being transported and adjusts the rolling marks of the annular substrate so that the detected rolling marks are aligned in a certain direction, The system includes an inspection conveyor for transporting the annular substrate with its rolled surface aligned in a specific direction, a first illumination device for irradiating the annular substrate with light from above, and a first line camera for photographing the light-irradiated surface of the annular substrate, and a first defect inspection unit for inspecting defects on the surface of the annular substrate using the image of the light-irradiated surface captured by the first line camera, A substrate holding device that adsorbs and transports the upper surface of the annular substrate, whose rolled surface is aligned in a certain direction; a second illumination device that irradiates light from below onto the annular substrate, whose upper surface is held by the substrate holding device; and a second line camera that photographs the light-irradiated surface of the annular substrate, and a second defect inspection unit that inspects defects on the back surface of the annular substrate using the image of the light-irradiated surface captured by the second line camera. The system comprises a stacking device for stacking the annular substrates after inspection has been completed, Pretreatment device for straightening and annealing of annular substrates.

[0014] The above objective of the present invention is achieved by the configuration described in [2] below, relating to a pretreatment method for straightening and annealing an annular substrate. [2] A pretreatment method for straightening annular substrate for inspecting defects present on the surface of annular substrate before straightening annealing, An adjustment step involves detecting the rolled marks on the transported annular substrate and adjusting the rolled marks on the annular substrate so that the detected rolled marks are aligned in a certain direction. A first defect inspection step involves irradiating the annular substrate, which is being transported with its rolled surface aligned in a certain direction, with light from above using a first illumination device, and inspecting for defects on the surface of the annular substrate using an image of the light-irradiated surface of the annular substrate captured by a first line camera, A substrate holding device that adsorbs and conveys the upper surface side of the annular substrate with the rolling marks aligned in a certain direction, a second illumination device that irradiates light from below onto the annular substrate whose upper surface side is held by the substrate holding device, and a second line camera that photographs the light irradiation surface of the annular substrate, and a second defect inspection process for inspecting defects on the back surface of the annular substrate using an image of the light irradiation surface imaged by the second line camera. A stacking process for stacking the annular substrates for which the inspection has been completed. A pretreatment method for annealing the correction of an annular substrate.

Effect of the Invention

[0015] According to the pretreatment apparatus and pretreatment method for annealing the correction of the annular substrate of the present invention, even for an annular substrate with non-aligned rolling marks, inspection can be continuously performed without stopping the conveying means, and defects of the annular substrate punched out from a rolled metal plate can be efficiently and accurately detected without providing a plurality of light sources irradiated from different angles or performing correction processing. Further, since annular substrates confirmed to have no foreign matter on the front and back surfaces can be stacked for annealing correction, it is possible to prevent the occurrence of indentation defects on the surface of the annular substrate due to annealing correction.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic diagram showing the configuration of the inspection apparatus for an annular substrate of the present invention. [Figure 2] It is a schematic diagram showing a phase adjustment device, a surface inspection device, and a back surface inspection device. [Figure 3] (a) is a schematic diagram showing the flare appearing on the surface of the metal substrate, and (b) is a schematic diagram showing the angle α formed by the conveying direction of the metal substrate and the flare. [Figure 4] It is a top view showing a phase matching part. [Figure 5] It is a side view showing a phase matching part. [Figure 6](A) is a schematic diagram showing the operation of the suction conveyor, and (B) is a bottom view of the suction conveyor. [Figure 7] This is a plan view showing the unloading equipment. [Figure 8] (A) and (B) are model diagrams showing a stacking device. [Modes for carrying out the invention]

[0017] Hereinafter, a pretreatment apparatus for straightening annealing of an annular substrate and a pretreatment method for straightening annealing of an annular substrate according to one embodiment of the present invention will be described with reference to the drawings. Furthermore, this embodiment is merely an example of the present invention, and the present invention is not limited to this embodiment. In addition, various modifications or improvements can be made to this embodiment, and such modified or improved forms may also be included in the present invention.

[0018] As shown in Figure 1, the inspection apparatus for annular substrates in this embodiment comprises, in order from the upstream side in the transport direction, a film forming apparatus 10, a punching apparatus 20, a phase adjustment apparatus 40, a surface inspection apparatus 60, a back surface inspection apparatus 70, a discharge apparatus 80, and a stacking apparatus 100. Each apparatus will be described in detail below, but the inspection apparatus of the present invention targets annular aluminum substrates punched out from rolled aluminum plates during the manufacturing process of HDD disk substrates. Therefore, in this embodiment, this aluminum substrate is shown as a metal substrate W. Furthermore, the film forming apparatus 10, the punching apparatus 20, the phase adjustment apparatus 40, the surface inspection apparatus 60, the back surface inspection apparatus 70, the discharge apparatus 80, and the stacking apparatus 100 are connected to the processing unit 110 by wire or wireless, and control is performed for each apparatus. Each apparatus may also be provided with a separate control unit, which is not shown.

[0019] (Film forming device 10) The film forming apparatus 10 performs a film forming process in which the oxide film on the surface of the aluminum plate, which is the material for the metal substrate W, is removed, and a non-conductive film consisting of an insoluble residue is formed. Hereinafter, when referring to an aluminum plate, both pure aluminum plates and aluminum alloy plates are included.

[0020] In the film formation process, the aluminum plate is washed with a predetermined etching solution to dissolve and remove the oxide film on the surface of the aluminum plate. In place of the oxide film, a thin, non-conductive film consisting of an insoluble residue is formed on the surface of the aluminum plate. This non-conductive film prevents the metal substrates W from bonding and adhering to each other during the straightening annealing process.

[0021] The non-conductive film preferably contains 80% by weight or more of one or more compounds selected from sodium hydroxide, magnesium oxide, aluminum oxide, aluminum nitrate, and aluminum sulfate. As an etching solution that also forms a non-conductive film, it is particularly preferable to use an aqueous sodium hydroxide solution.

[0022] Furthermore, the amount of insoluble residue forming the non-conductive film is 0.1 g / m². 2 More than 3.0g / m 2 Less than 0.1 g / m² is preferable. 2 If the amount is less than 3.0 g / m², it is not possible to sufficiently promote the separation of the stacked metal substrates W when the metal substrates W are annealed. On the other hand, if the amount of insoluble residue is 3.0 g / m² 2 In this case, the non-conductive film itself can cause clogging of the grinding wheel, making grinding after corrective annealing difficult.

[0023] (Punching device 20) In the punching device 20, as the next step after the film formation process by the film formation device 10, a punching process is performed in which an annular metal substrate W is punched out from the aluminum plate on which the non-conductive film has been formed using a press device (not shown).

[0024] The punching process allows for the manufacture of a metal substrate W with an insulated film formed on both the front and back surfaces. The metal substrates W manufactured in the punching process are transported one by one to a phase adjustment device 40 by a conveyor (not shown).

[0025] (Phase adjustment device 40) The phase adjustment device 40 includes a phase detection unit 41 and a phase alignment unit (phase adjustment conveyor) 42. In the phase adjustment device 40, as the next step after the punching process by the punching device 20, the phase detection unit 41 detects the phase consisting of the rolling marks Wa of the conveyed metal substrate W, and the phase alignment unit 42 performs a phase adjustment process (adjustment process) to align the phase of the metal substrate W in a certain direction.

[0026] The phase detection unit 41 first receives the metal substrate W being transported from the punching machine 20 via the first transport conveyor 46 and irradiates light onto the metal substrate W from a ring illumination device 47, which is an illumination device for phase detection, positioned above the metal substrate W. The surface of the metal substrate W has minute, striated irregularities, i.e., rolling marks Wa, formed on it due to rolling. When light is irradiated onto the surface of the metal substrate W, as shown in Figure 3(a), light rays 15 perpendicular to the rolling marks Wa appear, and these light rays 15 are captured by a CCD camera 48, which is an area camera used as an imaging device for phase detection.

[0027] Then, as shown in Figure 3(b), the processing unit 110 determines the angle α between the axis C1 of the light ray 15 and the axis C2 of the transport direction of the metal substrate W.

[0028] The phase alignment section 42 is located downstream of the first conveyor belt 46 and includes a first angle-swinging conveyor section 51 and a second angle-swinging conveyor section 52, which are provided on both sides in the width direction of the conveying path and are driven independently of each other to convey at different speeds. Figure 4 is a top view of the phase alignment section 42, and Figure 5 is a side view thereof.

[0029] The first angle-swinging conveyor section 51 and the second angle-swinging conveyor section 52 each include servo motors (drive motors) 51a and 52a mounted on the housing 50, a power transmission section 58 such as a belt pulley arranged inside the housing 50 to transmit power from the servo motors 51a and 52a to the drive pulley 53a, and a plurality of conveyor belts 54 and 55 with a circular cross-section (two in this embodiment) wrapped around the drive pulley 53a and a plurality of driven pulleys 53b.

[0030] Furthermore, the first angle-swinging conveyor section 51 and the second angle-swinging conveyor section 52 are provided with resin guide members 56 having guide surfaces that extend along the conveying direction, on the portion of the housing 50 facing the outer surface of the metal substrate W being conveyed, so as to guide the outer surface of the metal substrate W.

[0031] As a result, the transport speed of the first angle-swinging conveyor section 51 is adjusted by the rotation speed of the servo motor 51a, and the transport speed of the second angle-swinging conveyor section 52 is adjusted by the rotation speed of the servo motor 52a. Furthermore, by making the transport speeds of the first angle-swinging conveyor section 51 and the second angle-swinging conveyor section 52 different, the metal substrate W rotates horizontally while being transported at high speed through the phase alignment section 42 in approximately 0.5 seconds, guided by the guide surface of the guide member 56.

[0032] In other words, if the transport speed of the first angle-swinging conveyor section 51 is set faster than the transport speed of the second angle-swinging conveyor section 52, the metal substrate W will rotate clockwise in Figure 4. Conversely, if the transport speed of the second angle-swinging conveyor section 52 is set faster than the transport speed of the first angle-swinging conveyor section 51, the metal substrate W will rotate counterclockwise in Figure 4. Therefore, by adjusting the difference in transport speed between the first angle-swinging conveyor section 51 and the second angle-swinging conveyor section 52 according to the angle α formed by the axis C1 of the light ray 15 detected by the phase detection section 41 and the axis C2 of the transport direction of the metal substrate W, the angle α of the metal substrate W can be kept within a predetermined range.

[0033] Furthermore, the first angle-swinging conveyor section 51 and the second angle-swinging conveyor section 52 reduce the contact area with the metal substrate W by using conveyor belts 54 and 55 with a circular cross-section, while the load on the metal substrate W can be distributed by using two conveyor belts 54 and 55. As a result, even if the conveyor belts 54 and 55 come into sliding contact with the metal substrate W during phase adjustment, the metal substrate W can be transported at high speed without being damaged.

[0034] The rolled marks Wa of the metal substrates W transported from the punching machine 20 are oriented in various directions for each substrate W, and the angle α also has various values. However, the phase alignment unit 42 ensures that the rolled marks Wa of all metal substrates W are substantially aligned in the transport direction. In this embodiment, the resolution of the angle α by the phase alignment unit 42 is ±2°, and the correction accuracy is within ±5°.

[0035] Furthermore, the phase alignment unit 42 is equipped with an upstream transmission sensor 57A and a downstream transmission sensor 57B on the upstream and downstream sides of the first angle swing conveyor unit 51 and the second angle swing conveyor unit 52, respectively. Furthermore, if the upstream transmission sensor 57A detects the input of a metal substrate W before the downstream transmission sensor 57B detects the discharge of the metal substrate W, the surface inspection device 60 will either not perform the inspection on the metal substrate W detected by the upstream transmission sensor 57A, or will not treat the inspection result as a correct inspection, and will send it to the next process.

[0036] In this embodiment, the phase detection unit 41 detects the angle α when the metal substrate W is on the first conveyor belt 46, but it may also be performed when the metal substrate W is on the first angle swing conveyor belt 51 and the second angle swing conveyor belt 52 of the phase alignment unit 42. In this case, the phase detection unit 41 detects the angle α upstream of the first angle swing conveyor belt 51 and the second angle swing conveyor belt 52, and then the adjustment of the conveying speed of the first angle swing conveyor belt 51 and the second angle swing conveyor belt 52 is started.

[0037] (Surface inspection device 60) The surface inspection device 60 performs a first defect inspection process in the next step after the phase alignment unit 42, which involves inspecting for defects on the surface of the metal substrate W. As shown in Figure 2, the inspection method involves irradiating the surface of the metal substrate W, which is being transported by the inspection conveyor 63, with light from a first illumination device 64 positioned above the inspection conveyor 63, and then using a CCD line camera, which is a first imaging device 65 positioned above the first illumination device 64, to photograph the surface of the metal substrate W and perform image analysis to check for defects.

[0038] The first illumination device 64 uses line-type illumination so that the entire width of the metal substrate W to be photographed by the first imaging device 65 is illuminated. Since the first imaging device 65 uses a CCD line camera, observation is possible if there is a gap the size of one line of the CCD array, and stable inspection is possible by scanning and combining the imaging results.

[0039] Furthermore, because the direction of the rolling marks Wa of the metal substrate W is aligned by the phase alignment unit 42, the metal substrate W imaged by the first imaging device 65 is eliminated from the camera image for all metal substrates W, preventing diffuse reflection and dark-field conditions, thus enabling high-precision line inspection.

[0040] (Back surface inspection device 70) The back surface inspection device 70 performs a second defect inspection process in the next step after the first defect inspection process, which inspects for defects on the back surface of the metal substrate W. As shown in Figure 2, the inspection method involves using a suction conveyor 71 to lift the top surface of the metal substrate W, irradiating the back surface of the metal substrate W with light using a second illumination device 72 positioned below the suction conveyor 71, and using a second imaging device 73, which is a CCD line camera, to photograph the back surface of the metal substrate W and perform image analysis to check for defects.

[0041] The second illumination device 72 uses line-type illumination so that the entire width of the metal substrate W, which is photographed by the second imaging device 73, can be illuminated. Since the second imaging device 73 uses a CCD line camera, observation is possible if there is a gap the size of one line of the CCD array, and stable inspection is possible by scanning and combining the imaging results.

[0042] The suction conveyor 71 comprises a rectangular parallelepiped housing 74 with an open bottom, a pair of left and right suction conveying belts 75, 75 extending along the longitudinal direction on the lower surface of the housing 74, and a suction device 76 positioned on the upper upstream side of the housing 74.

[0043] The suction conveyor 71 can transport the metal substrate W, which has been picked up by the suction device 76 onto the suction conveyor belt 75 at the transport end of the inspection conveyor 63, to the start end of the second transport conveyor 81. At this time, the metal substrate W is supported on its upper side by the suction conveyor belt 75 and its lower side is open. Therefore, as shown in Figure 2, the lower side of the metal substrate W can be photographed by the second imaging device 73, which is positioned below the gap formed between the inspection conveyor 63 and the second transport conveyor 81.

[0044] Here, the suction conveyor 71 will be described in detail based on Figure 6. Figure 6(A) is a model diagram showing the operation of the suction conveyor, and Figure 6(B) is a bottom view of the main part of the suction conveyor.

[0045] As shown in Figures 6(A) and 6(B), the suction conveying belts 75, 75 are routed by a plurality of driven pulleys 77 arranged in a row along the longitudinal direction of the housing 74 and a drive pulley 78 driven by a motor (not shown). The suction conveying belts 75 are arranged in pairs on both sides in the width direction of the conveying path on the lower surface of the housing 74, thereby supporting both outer edges of the upper surface of the metal substrate W. As a result, an opening is formed between the pair of suction conveying belts 75, on the longitudinal center side of the lower surface of the housing 74.

[0046] As shown in Figure 6(B), the suction conveying belt 75 is formed with a circular cross-section to reduce the contact area with the metal substrate W, while the use of two conveyor belts 75A and 75B distributes the load on the metal substrate W. As a result, even if the conveyor belts 75A and 75B come into sliding contact with the metal substrate W during transport, the metal substrate W can be transported at high speed without being damaged.

[0047] The suction device 76 is positioned between the left and right pair of suction conveying belts 75, 75, and is located towards the end of the conveying section of the inspection conveyor 63 when viewed from the side.

[0048] According to the suction conveyor 71 configured as described above, first, the metal substrate W that has been transported to the end of the inspection conveyor 63 is sucked up by the suction device 76, and both ends of the upper surface of the metal substrate W are supported by the suction conveying belts 75, 75. Next, the metal substrate W, which is supported by the suction conveying belts 75, 75 by the suction device 76, is transported by the suction conveying belts 75, 75 to the second conveying conveyor 81 on the downstream side. Next, the metal substrate W that has been transported by the suction conveying belts 75, 75 to the starting end of the second conveying conveyor 81 falls free onto the second conveying conveyor 81 by its own weight because the suction force received from the suction device 76 weakens as the distance to the suction device 76 increases. As described above, the suction conveyor 71 can transport the metal substrate W that has been adsorbed onto the suction conveying belt 75 by the suction device 76.

[0049] Furthermore, the rolling marks Wa formed on the front and back surfaces of the metal substrate W are formed in substantially the same direction on both sides of the metal substrate W. Therefore, the metal substrate W received by the suction conveyor 71 of the back surface inspection device 70 from the inspection conveyor 63 of the surface inspection device 60 is maintained in a state of aligned phase by the phase alignment unit 42. In other words, the suction conveyor 71 can transport metal substrate W with aligned rolling marks Wa on the back surface.

[0050] The metal substrates W imaged by the first imaging device 65 and the second imaging device 73 are aligned in the direction of the rolling grain Wa of the metal substrates W by the phase alignment unit 42. As a result, diffuse reflection and dark field conditions do not occur in the camera image for all metal substrates W, enabling high-precision line inspection.

[0051] As described above, the defect inspection of the front and back surfaces of the metal substrate W is completed. Note that the front surface inspection device 60 and the back surface inspection device 70 may be arranged in reverse order, provided that the metal substrate W to be inspected has undergone the phase adjustment process by the phase adjustment device 40.

[0052] (Unloading device 80) In the discharge device 80, the next step after the second defect inspection process is a discharge process in which the inspected metal substrates W are sorted and discharged. As shown in Figures 2 and 7, the discharge device 80 includes a second transport conveyor 81 that receives the metal substrates W that have been transported by suction at the transport end of the suction conveyor 71, a sorting conveyor 82 that sorts the metal substrates W received from the second transport conveyor 81 to three locations according to the inspection results, and three discharge conveyors 83, 84, and 85 that discharge the metal substrates W that have been inspected from the sorting conveyor 82.

[0053] The distribution conveyor 82 is positioned downstream of the second transport conveyor 81 and is pivotally supported so as to be able to swing from side to side around its transport base end.

[0054] Downstream of the sorting conveyor 82, the following conveyors are arranged radially in a plan view as destinations for the inspection-completed metal substrates W: a first discharge conveyor 83 for discharging metal substrates W1 in which no defects were found, a second discharge conveyor 84 for discharging metal substrates W2 in which defects were found, and a third discharge conveyor 85 for discharging metal substrates W3 in which there were problems in the inspection process.

[0055] As described above, the surface inspection device 60 and the back surface inspection device 70 determine whether the metal substrate W is a metal substrate W1 in which no defects were found, a metal substrate W2 in which defects were found, or a metal substrate W3 that requires reinspection because the inspection was not performed properly or visual inspection is required. For this reason, the sorting conveyor 82 sorts the metal substrates W1, W2, and W3 to their respective destinations by oscillating from side to side according to the inspection results.

[0056] (Stacking device 100) The stacking device 100 performs a stacking process in the next step after the discharge process, in which metal substrates W1 are stacked to create a laminate. The stacking device 100 includes a reversing device 90 that can rotate the metal substrates W1 received from the first discharge conveyor 83 by half a turn so that the top surface is flipped from the front surface H to the back surface T, and a good product recovery device 86 that collects the stacked metal substrates W1 downstream of the reversing device 90.

[0057] As shown in Figure 8, the inversion device 90 includes a stacking conveyor 92 that transports the metal substrate W1 received from the first discharge conveyor 83 to the good product recovery device 86, and an air blow device 91 that can rotate the metal substrate W1 received by the stacking conveyor 92 by half a turn, inverting it from the front surface H to the back surface T.

[0058] The stacking conveyor 92 extends from the transport end side of the first discharge conveyor 83 toward the good product recovery device 86 in a plan view. Furthermore, the base end of the stacking conveyor 92 is positioned below the transport end side of the first discharge conveyor 83 in a side view. This allows the stacking conveyor 92 to transport the metal substrates W1 received from the transport end side of the first discharge conveyor 83 toward the good product recovery device 86, as shown in Figures 7 and 8(A).

[0059] The air blow device 91 is positioned above the transport end of the first discharge conveyor 83 and is configured to supply air toward the upper surface of the metal substrate W1 that has been transported toward the transport end of the first discharge conveyor 83.

[0060] As shown in Figure 8(B), the air blow device 91 supplies air to the front upper surface of the metal substrate W1 when at least the front half of the metal substrate W1 protrudes in the transport direction from the transport end side of the first discharge conveyor 83, thereby causing the metal substrate W1 falling toward the stacking conveyor 92 to rotate half a turn in the forward direction. The timing of the air supply by the air blow device 91 is not limited to the above, as long as it is sufficient for the metal substrate W1 to rotate half a turn on the stacking conveyor 92.

[0061] As described above, the stacking device 100 can control whether the metal substrate W1 being transported from the first discharge conveyor 83 to the stacking conveyor 92 is facing upwards with its surface H or its back surface T, depending on whether or not air is supplied by the air blow device 91.

[0062] The good product recovery device 86 includes a disc-shaped turntable 86b in which vertical support shafts 86a through which the central hole of the metal substrate W1 is inserted are arranged at predetermined angles, a motor (not shown) that rotates the turntable around the central axis, and a sensor (not shown) that detects the height of the metal substrate W stacked on the support shafts 86a. In the illustrated example, the support shafts 86a on the turntable 86b are arranged at 90° intervals around a central rotation axis and rotated at 90° intervals by the motor.

[0063] As described above, the stacking device 100 can create a laminate by alternately transporting metal substrates W1 with their surface H facing upward and metal substrates W1 with their back surface T facing upward to the good product recovery device 86 using the inversion device 90, thereby alternating between the surface H and back surface T of the metal substrates W1.

[0064] Here, the press-formed metal substrate W1 has a curved surface that curves slightly from the center of the surface H, which is the punch side for pressing the aluminum plate, towards the periphery of the back surface T, which is the die side for supporting the aluminum plate. In contrast, by straightening and annealing the laminate created by the stacking device 100, in which the surface H and back surface T are alternately stacked, the residual stresses generated in opposite directions on the surface H and back surface T of the metal substrate W1 cancel each other out, thereby improving the flatness.

[0065] Incidentally, the metal substrates W2 in which defects were found and the metal substrates W3 requiring re-inspection, which were sorted by the conveying device 80, are recovered by the defective product recovery device 87 and the re-inspection product recovery device 88, respectively, without going through the stacking device 100. The defective product recovery device 87 is located on the conveying end side of the second discharge conveyor 84, and the re-inspection product recovery device 88 is located on the conveying end side of the third discharge conveyor 85.

[0066] The defective product retrieval device 87 and the re-inspection product retrieval device 88 each include a turntable made of a longitudinal plate-shaped member with vertically oriented support shafts arranged at both ends through which the central holes of metal substrates W2 and W3 are inserted; a motor (not shown) that rotates the turntable around the central shaft; and a sensor (not shown) that detects the height of the metal substrates W stacked on the support shafts. In the illustrated example, the turntable rotates every 180° by the motor.

[0067] As described above, each recovery device 86, 87, and 88 creates a stack of metal substrates W by inserting the center of the metal substrate W through the support shaft. When it is detected that the stacked metal substrates W on the turntable have reached a predetermined height, the turntable is rotated so that the adjacent support shaft is positioned towards the transport end of each discharge conveyor. In other words, the worker can efficiently discharge the metal substrates W1, W2, and W3 discharged from each discharge conveyor 83, 84, and 85 after stacking a predetermined number of them using each recovery device 86, 87, and 88.

[0068] According to the preprocessing apparatus of this embodiment, the surface of a disk substrate formed by rolling and punching a metal plate can be inspected with high precision for defects, and only disk substrates that do not show defects can be stacked in preparation for corrective annealing. The disk substrates that pass both the surface inspection apparatus 60 and the back surface inspection apparatus 70 are then subjected to corrective annealing and grinding according to conventional methods to become a ground substrate, which is then subjected to zincate treatment, electroless nickel-phosphorus plating, polishing, and a magnetic film is deposited on top by sputtering.

[0069] It should be noted that the present invention is not limited to the embodiments described above, and can be modified or improved as appropriate. For example, the phase adjustment conveyor of this embodiment is not limited to surface inspection systems, but can be applied to any system that requires a mechanism to rotate a ring-shaped metal substrate while transporting it.

[0070] As described above, the following matters are disclosed in this specification: (1) A pre-treatment device for straightening annular substrates for inspecting defects present on the surface of annular substrates before straightening annealing, An adjustment unit that detects the rolling marks of the annular substrate being transported and adjusts the rolling marks of the annular substrate so that the detected rolling marks are aligned in a certain direction, The system includes an inspection conveyor for transporting the annular substrate with its rolled surface aligned in a specific direction, a first illumination device for irradiating the annular substrate with light from above, and a first line camera for photographing the light-irradiated surface of the annular substrate, and a first defect inspection unit for inspecting defects on the surface of the annular substrate using the image of the light-irradiated surface captured by the first line camera, A substrate holding device that adsorbs and transports the upper surface of the annular substrate, whose rolled surface is aligned in a certain direction; a second illumination device that irradiates light from below onto the annular substrate, whose upper surface is held by the substrate holding device; and a second line camera that photographs the light-irradiated surface of the annular substrate, and a second defect inspection unit that inspects defects on the back surface of the annular substrate using the image of the light-irradiated surface captured by the second line camera. The system comprises a stacking device for stacking the annular substrates after inspection has been completed, Pretreatment device for straightening and annealing of annular substrates. This configuration allows for continuous inspection of annular substrates with uneven rolling marks without stopping the transport mechanism, and enables accurate and rapid detection of defects on the front and back surfaces of each annular substrate punched from a rolled metal sheet without the need for multiple light sources or correction processing. Furthermore, since the inspected annular substrates are stacked directly for straightening annealing, dust cannot be trapped between the annular substrates.

[0071] (2) The substrate holding device comprises a suction device positioned in a location that overlaps with the second line camera in a plan view and which sucks the central side of the upper surface of the annular substrate, and a pair of left and right suction conveying belts that extend along the conveying direction and are arranged to support both ends of the outer circumference of the upper surface of the annular substrate, (1) Pretreatment apparatus for straightening annealing of an annular substrate as described in (1). With this configuration, the substrate holding device can photograph the back surface of the annular substrate while it is being transported, allowing for efficient inspection without having to flip the annular substrate over.

[0072] (3) The adjustment unit is The system includes an illumination device for detecting the rolling marks on the annular substrate, an area camera for photographing the light-illuminated surface of the annular substrate, and a first angle-swinging conveyor section and a second angle-swinging conveyor section arranged side by side along the transport direction and driven independently of each other to transport at different transport speeds. The area camera captures the light rays appearing perpendicular to the rolling marks of the annular substrate, and detects the angle that the axis of the light rays makes with respect to the transport direction. Based on this angle, the transport speeds of the first angle-swinging conveyor section and the second angle-swinging conveyor section are adjusted to rotate the annular substrate horizontally while transporting it, thereby aligning the angle within a predetermined range with respect to the transport direction of the annular substrate. (1) or (2) Pretreatment apparatus for straightening annealing of an annular substrate. With this configuration, annular substrates with aligned rolling marks can be sent to the first defect inspection unit, enabling accurate defect inspection of the annular substrates.

[0073] (4) A punching device is provided upstream of the adjustment section for punching out the annular substrate from the rolled metal sheet, A pretreatment device for straightening and annealing annular substrates as described in any one of items (1) to (3). This configuration allows for the integrated production of annular substrates by punching out rolled metal sheets, inspection of defects on the front and back surfaces of the annular substrates, and stacking of the annular substrates after inspection, thereby increasing work efficiency.

[0074] (5) The punching device has a film forming device that forms a non-conductive film on the rolled metal sheet before it. (4) Pretreatment apparatus for straightening annealing of an annular substrate as described above. This configuration prevents adjacent annular substrates from adhering to each other when multiple annular substrates are stacked and then straightened and annealed, thereby maintaining the peelability of the stacked annular substrates.

[0075] (6) The insulator film formed on the rolled metal sheet contains 80% by weight or more of one or more compounds selected from sodium hydroxide, magnesium oxide, aluminum oxide, aluminum nitrate, and aluminum sulfate. (5) Pretreatment apparatus for straightening annealing of an annular substrate as described in (5). This configuration allows for the use of relatively inexpensive materials to keep costs down while preventing adjacent annular substrates from sticking together and maintaining the peelability of the laminated annular substrates.

[0076] (7) The non-conductive film formed on the rolled metal sheet is 0.1 g / m 2 More than 3g / m 2 Less than (5) or (6) Pretreatment apparatus for straightening annealing of annular substrates. This configuration makes it possible to remove the oxide film from the surface of the rolled metal sheet and to form a non-conductive film of appropriate thickness on the surface of the rolled metal sheet simultaneously.

[0077] (8) The stacking device has a reversing device that reverses the front and back surfaces of the annular substrate whose rolled surface has been aligned by the adjustment unit, and stacks the annular substrate with the top surface facing outwards and the annular substrate with the top surface facing outwards alternately. A pretreatment device for straightening and annealing annular substrates as described in any one of items (1) to (7). According to this configuration, the annular substrates can be made flatter by straightening and annealing a laminate of stacked annular substrates, in which the front and back surfaces are alternately flipped.

[0078] (9) A pretreatment method for straightening annular substrate for inspecting defects present on the surface of annular substrate before straightening annealing, An adjustment step involves detecting the rolled marks on the transported annular substrate and adjusting the rolled marks on the annular substrate so that the detected rolled marks are aligned in a certain direction. A first defect inspection step involves irradiating the annular substrate, which is being transported with its rolled surface aligned in a certain direction, with light from above using a first illumination device, and inspecting for defects on the surface of the annular substrate using an image of the light-irradiated surface of the annular substrate captured by a first line camera, A substrate holding device that adsorbs and transports the upper surface of the annular substrate, whose rolled surface is aligned in a certain direction; a second illumination device that irradiates light from below onto the annular substrate, whose upper surface is held by the substrate holding device; and a second line camera that photographs the light-irradiated surface of the annular substrate, wherein a second defect inspection step inspects defects on the back surface of the annular substrate using the image of the light-irradiated surface captured by the second line camera. The process includes a stacking step of stacking the annular substrates after inspection has been completed, A pretreatment method for straightening and annealing annular substrates. This configuration allows for continuous inspection of annular substrates with uneven rolling marks without stopping the transport mechanism, and enables accurate and rapid detection of defects on the front and back surfaces of each annular substrate punched from a rolled metal sheet without the need for multiple light sources or correction processing. Furthermore, since the inspected annular substrates are stacked directly for straightening annealing, dust cannot be trapped between the annular substrates.

[0079] (10) The second defect inspection step involves using a suction device positioned to overlap with the second line camera in a plan view to suck the central side of the upper surface of the annular substrate, and using a pair of left and right suction conveying belts extending along the conveying direction to support both ends of the outer circumference of the upper surface of the annular substrate, thereby holding and conveying the upper surface of the annular substrate with the rolled grain aligned in a certain direction. (9) A pretreatment method for straightening and annealing an annular substrate as described in (9). With this configuration, the substrate holding device can photograph the back surface of the annular substrate while it is being transported, allowing for efficient inspection without having to flip the annular substrate over.

[0080] (11) The adjustment step involves irradiating the annular substrate with light using an illumination device for detecting rolling marks, detecting the angle that the axis of the light rays appearing perpendicular to the rolling marks of the annular substrate makes with respect to the transport direction using an image of the light-irradiated surface of the annular substrate captured by an area camera, and adjusting the transport speeds of the first angle-swinging conveyor section and the second angle-swinging conveyor section, which are arranged side by side along the transport direction and driven independently of each other to transport at different transport speeds, based on the angle, and rotating the annular substrate horizontally while transporting it, thereby aligning the angle within a predetermined range with respect to the transport direction of the annular substrate. (9) or (10) A pretreatment method for straightening and annealing an annular substrate. This configuration allows for the inspection of annular substrates with aligned rolling marks, enabling accurate defect inspection of annular substrates.

[0081] (12) The process further comprises, before the adjustment process, a punching process in which the annular substrate is punched out from the rolled metal sheet. A pretreatment method for straightening and annealing an annular substrate as described in any one of items (9) to (11). This configuration allows for the integrated production of annular substrates by punching out rolled metal sheets, inspection of defects on the front and back surfaces of the annular substrates, and stacking of the annular substrates after inspection, thereby increasing work efficiency.

[0082] (13) A film forming step is provided before the punching step in which a non-conductive film is formed on the rolled metal sheet. (12) A pretreatment method for straightening and annealing an annular substrate as described in (12). This configuration prevents adjacent annular substrates from adhering to each other when multiple annular substrates are stacked and then straightened and annealed, thereby maintaining the peelability of the stacked annular substrates.

[0083] (14) The film formation step involves forming a non-conductive film on the rolled metal sheet containing 80% by weight or more of one or more compounds selected from sodium hydroxide, magnesium oxide, aluminum oxide, aluminum nitrate, and aluminum sulfate. (13) A pretreatment method for straightening and annealing an annular substrate as described in (13). This configuration allows for the use of relatively inexpensive materials to keep costs down while preventing adjacent annular substrates from sticking together and maintaining the peelability of the laminated annular substrates.

[0084] (15) The film formation step is to form the insulator film on the rolled metal sheet at a rate of 0.1 g / m 2 More than 3g / m 2 Less than (13) or (14) Pretreatment method for straightening and annealing an annular substrate. This configuration makes it possible to remove the oxide film from the surface of the rolled metal sheet and to form a non-conductive film of appropriate thickness on the surface of the rolled metal sheet simultaneously.

[0085] (16) The stacking step involves alternately inverting the front and back surfaces of the annular substrate whose rolled surface has been aligned by the adjustment step, thereby alternately stacking the annular substrate with the top surface facing outwards and the annular substrate with the top surface facing outwards. A pretreatment method for straightening and annealing an annular substrate as described in any one of items (9) to (15). According to this configuration, the annular substrates can be made flatter by straightening and annealing a laminate of stacked annular substrates, in which the front and back surfaces are alternately flipped. [Explanation of Symbols]

[0086] 2 Laminate 10 Film forming device 15 Ray of Light 20 Punching device 40 Phase adjustment device (adjustment unit) 47. Ring illumination (illumination device for detecting rolling marks) 48 CCD cameras (area cameras) 51 First angle-swinging conveyor section 52 Second angle-swinging conveyor section 60 Surface inspection device (first defect inspection unit) 63 Inspection conveyor 64. First lighting device 65 First imaging device (first line camera) 70. Back surface inspection device (second defect inspection section) 71. Suction conveyor (substrate holding device) 72 Second lighting device 73. Second imaging device (second line camera) 75 Suction conveyor belt 76 Suction device 80 Unloading device (unloading mechanism) 83. First discharge conveyor (first discharge section) 84. Second discharge conveyor (second discharge section) 85. Third discharge conveyor (third discharge section) 90. Reversing device (reversing mechanism) 100 Stacking device W Metal substrate (annular substrate) Wa Rolling

Claims

1. A pre-treatment device for straightening annealing of an annular substrate, which inspects for defects present on the surface of an annular substrate punched out from a rolled metal sheet before straightening annealing, An adjustment unit that detects the rolling marks of the annular substrate being transported and adjusts the rolling marks of the annular substrate so that the detected rolling marks are aligned in a certain direction, The system includes an inspection conveyor for transporting the annular substrate with its rolled surface aligned in a specific direction, a first illumination device for irradiating the annular substrate with light from above, and a first line camera for photographing the light-irradiated surface of the annular substrate, and a first defect inspection unit for inspecting defects on the surface of the annular substrate using the image of the light-irradiated surface captured by the first line camera, A substrate holding device that adsorbs and transports the upper surface of the annular substrate, whose rolled surface is aligned in a certain direction; a second illumination device that irradiates light from below onto the annular substrate, whose upper surface is held by the substrate holding device; and a second line camera that photographs the light-irradiated surface of the annular substrate, and a second defect inspection unit that inspects defects on the back surface of the annular substrate using the image of the light-irradiated surface captured by the second line camera. The system comprises a stacking device for stacking the annular substrates after inspection has been completed, The substrate holding device includes a suction device positioned in a location overlapping with the second line camera in a plan view and which sucks the central side of the upper surface of the annular substrate, and a pair of left and right suction conveying belts that extend along the conveying direction and are arranged to support both ends of the outer circumference of the upper surface of the annular substrate. A punching device is provided upstream of the adjustment section and punches out the annular substrate from the rolled metal sheet, Pretreatment device for straightening and annealing of annular substrates.

2. A pre-processing apparatus for straightening annealing of an annular substrate, which inspects defects present on the surface of an annular substrate punched out from a rolled metal sheet before straightening annealing, An adjustment unit that detects the rolling marks of the annular substrate being transported and adjusts the rolling marks of the annular substrate so that the detected rolling marks are aligned in a certain direction, The system includes an inspection conveyor for transporting the annular substrate with its rolled surface aligned in a specific direction, a first illumination device for irradiating the annular substrate with light from above, and a first line camera for photographing the light-irradiated surface of the annular substrate, and a first defect inspection unit for inspecting defects on the surface of the annular substrate using the image of the light-irradiated surface captured by the first line camera, A substrate holding device that adsorbs and transports the upper surface of the annular substrate, whose rolled surface is aligned in a certain direction; a second illumination device that irradiates light from below onto the annular substrate, whose upper surface is held by the substrate holding device; and a second line camera that photographs the light-irradiated surface of the annular substrate, and a second defect inspection unit that inspects defects on the back surface of the annular substrate using the image of the light-irradiated surface captured by the second line camera. The system comprises a stacking device for stacking the annular substrates after inspection has been completed, The adjustment unit is, The system includes an illumination device for detecting the rolling marks on the annular substrate, an area camera for photographing the light-illuminated surface of the annular substrate, and a first angle-swinging conveyor section and a second angle-swinging conveyor section arranged side by side along the transport direction and driven independently of each other to transport at different transport speeds. The area camera captures the light rays appearing perpendicular to the rolling marks of the annular substrate, and detects the angle that the axis of the light rays makes with respect to the transport direction. Based on this angle, the transport speeds of the first angle-swinging conveyor section and the second angle-swinging conveyor section are adjusted to rotate the annular substrate horizontally while transporting it, thereby aligning the angle within a predetermined range with respect to the transport direction of the annular substrate. A punching device is provided upstream of the adjustment section and punches out the annular substrate from the rolled metal sheet, Pretreatment device for straightening and annealing of annular substrates.

3. Prior to the punching device, there is a film forming device for forming a non-conductive film on the rolled metal sheet. A pretreatment apparatus for straightening and annealing an annular substrate according to claim 1 or 2.

4. The insulated film formed on the rolled metal sheet contains 80% by weight or more of one or more compounds selected from sodium hydroxide, magnesium oxide, aluminum oxide, aluminum nitrate, and aluminum sulfate. The pretreatment apparatus for straightening and annealing an annular substrate according to claim 3.

5. The non-conductive film formed on the rolled metal sheet is 0.1 g / m² ２ 3g / m or more ２ Less than The pretreatment apparatus for straightening and annealing an annular substrate according to claim 3.

6. The stacking device has a reversing device that reverses the front and back surfaces of the annular substrate whose rolled surface has been aligned by the adjustment unit, and stacks the annular substrate with the top surface facing outwards and the annular substrate with the top surface facing outwards alternately. A pretreatment apparatus for straightening and annealing an annular substrate according to claim 1 or 2.

7. A pretreatment method for straightening annealing of an annular substrate, which involves inspecting for defects present on the surface of an annular substrate punched out from a rolled metal sheet before straightening annealing, An adjustment step involves detecting the rolled marks on the transported annular substrate and adjusting the rolled marks on the annular substrate so that the detected rolled marks are aligned in a certain direction. A first defect inspection step involves irradiating the annular substrate, which is being transported with its rolled surface aligned in a certain direction, with light from above using a first illumination device, and inspecting for defects on the surface of the annular substrate using an image of the light-irradiated surface of the annular substrate captured by a first line camera, A substrate holding device that adsorbs and transports the upper surface of the annular substrate, whose rolled surface is aligned in a certain direction; a second illumination device that irradiates light from below onto the annular substrate, whose upper surface is held by the substrate holding device; and a second line camera that photographs the light-irradiated surface of the annular substrate, wherein a second defect inspection step inspects defects on the back surface of the annular substrate using the image of the light-irradiated surface captured by the second line camera. The process includes a stacking step of stacking the annular substrates after inspection has been completed, The second defect inspection step involves using a suction device positioned to overlap with the second line camera in a plan view to suck the central side of the upper surface of the annular substrate, and supporting both ends of the outer circumference of the upper surface of the annular substrate with a pair of left and right suction conveying belts extending along the conveying direction, thereby holding and conveying the upper surface of the annular substrate with the rolled grain aligned in a certain direction. The process further includes, prior to the adjustment step, a punching step in which the annular substrate is punched out from the rolled metal sheet, A pretreatment method for straightening and annealing annular substrates.

8. A pretreatment method for straightening and annealing an annular substrate, comprising inspecting for defects present on the surface of an annular substrate punched out from a rolled metal sheet before straightening and annealing, An adjustment step involves detecting the rolled marks on the transported annular substrate and adjusting the rolled marks on the annular substrate so that the detected rolled marks are aligned in a certain direction. A first defect inspection step involves irradiating the annular substrate, which is being transported with its rolled surface aligned in a certain direction, with light from above using a first illumination device, and inspecting for defects on the surface of the annular substrate using an image of the light-irradiated surface of the annular substrate captured by a first line camera, A substrate holding device that adsorbs and transports the upper surface of the annular substrate, whose rolled surface is aligned in a certain direction; a second illumination device that irradiates light from below onto the annular substrate, whose upper surface is held by the substrate holding device; and a second line camera that photographs the light-irradiated surface of the annular substrate, wherein a second defect inspection step inspects defects on the back surface of the annular substrate using the image of the light-irradiated surface captured by the second line camera. The process includes a stacking step of stacking the annular substrates after inspection has been completed, The adjustment process involves irradiating the annular substrate with light using an illumination device for detecting rolling marks, detecting the angle that the axis of the light rays appearing perpendicular to the rolling marks of the annular substrate makes with respect to the transport direction using an image of the light-irradiated surface of the annular substrate captured by an area camera, and adjusting the transport speeds of the first angle-swinging conveyor section and the second angle-swinging conveyor section, which are arranged side by side along the transport direction and driven independently to transport at different transport speeds, based on the angle, and rotating the annular substrate horizontally while transporting it, thereby aligning the angle within a predetermined range with respect to the transport direction of the annular substrate. The process further includes, prior to the adjustment step, a punching step in which the annular substrate is punched out from the rolled metal sheet, A pretreatment method for straightening and annealing annular substrates.

9. Prior to the punching process, a film forming process is provided in which a non-conductive film is formed on the rolled metal sheet. A pretreatment method for straightening and annealing an annular substrate according to claim 7 or 8.

10. The film formation step involves forming a non-conductive film on the rolled metal sheet containing 80% by weight or more of one or more compounds selected from sodium hydroxide, magnesium oxide, aluminum oxide, aluminum nitrate, and aluminum sulfate. The pretreatment method for straightening and annealing an annular substrate according to claim 9.

11. The aforementioned film formation step involves forming the non-conductive film on the rolled metal sheet at a rate of 0.1 g / m². ２ 3g / m or more ２ Less than The pretreatment method for straightening and annealing an annular substrate according to claim 9.

12. The stacking step involves alternately inverting the front and back surfaces of the annular substrates, whose rolled surface has been aligned by the adjustment step, thereby stacking the annular substrates with the top surface facing forward and the annular substrates with the top surface facing backward alternately. A pretreatment method for straightening and annealing an annular substrate according to claim 7 or 8.

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