Heat treatment device and heat treatment method for treatment object

Abstract

A heat treatment device disclosed in the present invention comprises a conveyance device, a first heating unit, and a second heating unit. The conveyance device conveys a belt-like treatment object along a predetermined conveyance path. The first heating unit includes a laser device that heats the treatment object by projecting laser light P thereon. The second heating unit includes a heating device that heats the treatment object heated by the first heating unit by a method other than laser heating.

Description

Heat treatment device and method for heat treatment of workpiece

[0001] The present disclosure relates to a heat treatment apparatus and a method for heat treating an object to be treated. This application claims priority to Japanese Patent Application No. 2023-171084, filed on October 2, 2023, the entire contents of which are incorporated herein by reference.

[0002] Japanese Patent No. 7285360 discloses a heat treatment apparatus including a heating section, a cooling section, and a winding section. In the heating section, a sheet is heated while being conveyed. In the cooling section, the sheet heated in the heating section is cooled while being conveyed. In the winding section, the sheet cooled in the cooling section is wound up. Guide rollers are arranged above and below the heating section from the entrance to the exit. The sheet is folded back by the guide rollers and conveyed from the entrance to the exit while moving up and down. Far-infrared heaters are provided in the gaps and around the sheet so as to face the sheet. This configuration is said to increase the distance the sheet is conveyed in the heating section, thereby efficiently drying the sheet.

[0003] Japanese Patent Application Laid-Open Publication No. 2014-107237 discloses an electrode sheet drying device for drying a roll-shaped electrode sheet. The drying device disclosed in this publication includes a chamber, a vacuum exhaust device that creates a vacuum pressure inside the chamber, an unwinding shaft, a winding shaft, a guide roller, and an infrared ray irradiation unit. The chamber includes an unwinding-side housing section, a winding-side housing section, and a communicating section. The unwinding-side housing section houses a winding shaft. The winding-side housing section houses a winding shaft. The communicating section connects the unwinding-side housing section and the winding-side housing section. The infrared ray irradiation unit is provided outside the chamber. The infrared ray irradiation unit irradiates the electrode sheet passing through the communicating section with infrared rays through a transmission window provided midway through the communicating section. This drying device is said to be able to uniformly dry the entire electrode sheet and to significantly reduce the drying time compared to conventional methods without thermally deteriorating the electrode sheet.

[0004] Japanese Patent No. 7285360 Japanese Patent Application Laid-Open No. 2014-107237

[0005] The present inventors wish to improve the processing efficiency of strip-shaped objects to be processed.

[0006] The heat treatment apparatus disclosed herein includes a conveying device, a first heating unit, and a second heating unit. The conveying device conveys a strip-shaped workpiece along a predetermined conveying path. The first heating unit has a laser device that irradiates the workpiece with laser light to heat it. The second heating unit has a heating device that heats the workpiece heated in the first heating unit by a method other than laser heating. In such a heat treatment apparatus, the processing efficiency of the strip-shaped workpiece is improved.

[0007] Fig. 1 is a schematic diagram showing a heat treatment apparatus 10. Fig. 2 is a schematic diagram showing a drive mechanism for driving a workpiece 20. Fig. 3 is a schematic diagram of a first heating section 40, a second heating section 50, and a cooling section 60. Fig. 4 is a graph showing the transition of the temperature of the workpiece 20. Fig. 5 is a schematic diagram showing a first heating section 40A according to another embodiment.

[0008] One embodiment of the present disclosure will be described in detail below with reference to the drawings. In the following drawings, components and parts that perform the same function are denoted by the same reference numerals. Furthermore, the dimensional relationships (length, width, thickness, etc.) in each drawing do not reflect the actual dimensional relationships. The directions of up, down, left, right, front, and rear are represented by arrows U, D, L, R, F, and Rr, respectively, in the drawings. Here, the directions of up, down, left, right, front, and rear are defined merely for the convenience of explanation and do not limit the present invention unless otherwise specified.

[0009] FIG. 1 is a schematic diagram showing a heat treatment apparatus 10. FIG. 1 schematically shows the internal configuration of the unwinding section 30 and the winding section 70. FIG. 2 is a schematic diagram showing a drive mechanism for driving the workpiece 20. FIG. 2 omits the illustration of the first heating section 40, the second heating section 50, and the cooling section 60 between the unwinding section 30 and the winding section 70. FIG. 2 also omits the illustration of rollers 34 other than the tension detection roller 34b, the feed roller 34c, and the dancer roller 34d of the unwinding section 30. FIG. 2 also omits the illustration of rollers 74 other than the tension detection roller 74c of the winding section 70. FIG. 3 is a schematic diagram of the first heating section 40, the second heating section 50, and the cooling section 60.

[0010] <Heat Treatment Device 10> The heat treatment device 10 is equipment for heat-treating a strip-shaped workpiece 20. In this embodiment, the heat treatment device 10 is an apparatus for continuously drying a strip-shaped workpiece while transporting it using a so-called roll-to-roll method. The workpiece 20 is not particularly limited as long as it is strip-shaped, such as, for example, an electrode sheet for a secondary battery in which electrode materials are applied to both sides of a sheet substrate, a flexible copper clad laminate (FCCL), or a polyimide sheet. The heat treatment device 10 disclosed herein can be used to treat various strip-shaped (sheet-shaped) workpieces.

[0011] 1, the workpiece 20 is heat-treated using a heat treatment apparatus 10. The heat treatment method for the workpiece 20 includes a first heating step and a second heating step. The heat treatment method for the workpiece 20 may also include a cooling step.

[0012] The heat treatment apparatus 10 includes a conveying device 80, a first heating section 40, and a second heating section 50. The workpiece 20 is conveyed along a predetermined conveying path in the heat treatment apparatus 10. The workpiece 20 is heat-treated while being conveyed along the conveying path in the first heating section 40 and the second heating section 50. In this embodiment, the heat treatment apparatus 10 includes an unwinding section 30 and a winding section 70. The conveying path for the workpiece 20 is set between the unwinding roll 22 of the unwinding section 30 and the winding roll 24 of the winding section 70. In this embodiment, the heat treatment apparatus 10 includes a cooling section 60. The workpiece 20 is provided between the second heating section 50 and the winding section 70. Therefore, the workpiece 20 is unwound in the unwinding section 30, heat-treated in the first heating section 40, heat-treated in the second heating section 50, cooled in the cooling section 60, and wound up in the winding section 70.

[0013] <Conveying Devices 80, 82> The conveying device 80 is a device that conveys the workpiece 20 along a predetermined conveying path. In this embodiment, the conveying devices 80, 82 are devices that rotate and drive the first shaft 32 to which the unwinding roll 22 of the unwinding section 30 is attached, and the second shaft 72 to which the winding roll 24 of the winding section 70 is attached. In this embodiment, motors are used as the conveying devices 80, 82.

[0014] 2, the conveying devices 80, 82 are attached to one outer wall 30a of the unwinding section 30 and one outer wall 70a of the winding section 70, respectively. The first shaft 32 is connected to the conveying device 80. The first shaft 32 is rotationally driven by the conveying device 80, and the workpiece 20 is unwound from the unwinding roll 22. The second shaft 72 is connected to the conveying device 82. The second shaft 72 is rotationally driven by the conveying device 82, and the workpiece 20 is wound onto the winding roll 24. The conveying devices 80, 82 may be installed in atmospheric boxes provided in spaces surrounded by the outer walls 30a, 70a, respectively.

[0015] In the heat treatment apparatus 10, the workpiece 20 can be transported at a high speed in order to improve the processing efficiency of the workpiece 20. Although not particularly limited, the transport speed of the workpiece 20 can be set to approximately 1 m / min to 200 m / min. In this embodiment, the transport speed of the workpiece 20 is set to approximately 100 m / min. In the heat treatment apparatus 10, the transport speed of the workpiece 20 is controlled by the control device 15.

[0016] <Control Device 15> The control device 15 controls the conveying speed of the workpiece 20 and the tension applied to the workpiece 20 so that the workpiece 20 is conveyed in accordance with predetermined conveying conditions. In this embodiment, the control device 15 controls the unwinding tension when unwinding the workpiece 20, the in-furnace tension applied to the workpiece 20 being treated, and the winding tension when winding the treated workpiece 20. As shown in FIG. 2 , the control device 15 is connected to the conveying devices 80 and 82. The control device 15 is also connected to the tension detection roller 34b, the feed roller 34c, the dancer roller 34d, the tension detection roller 74c, and the like. The tension detection roller 34b, the feed roller 34c, the dancer roller 34d, and the tension detection roller 74c will be described later. The control device 15 feeds back the unwinding tension detected by the tension detection roller 34b to the conveying device 80 and controls the torque of the first shaft 32. This adjusts the unwinding tension. The control device 15 also feeds back to the dancer roller 34d the in-furnace tension detected by a tension detection roller (in this embodiment, a tension detection roller 74c provided in the cooling section 60 (see FIG. 1)) around which the workpiece 20 being processed is hung. The dancer roller 34d moves according to the detected in-furnace tension, thereby adjusting the in-furnace tension. The rotation speed of the feed roller 34c is controlled so that the position of the dancer roller 34d returns to its reference position while the in-furnace tension remains constant. The control device 15 also feeds back to the conveying device 82 the winding tension detected by the tension detection roller 74c, and controls the torque of the second shaft 72. This adjusts the winding tension.

[0017] <Unwinding Section 30> The unwinding section 30 is a section that unwinds the workpiece 20. As shown in FIG. 1 , the unwinding section 30 houses the unwinding roll 22 around which the workpiece 20 is wound before being heat-treated. The unwinding section 30 has internal equipment and an outer wall 30a that surrounds the unwinding roll 22. In this embodiment, a transport space is formed inside the outer wall 30a, through which the workpiece 20 is transported and which is isolated from the outside. The unwinding section 30 is provided with a first shaft 32 and a plurality of rollers 34 inside. The first shaft 32 is a shaft on which the unwinding roll 22 around which the workpiece 20 is wound before being heat-treated is attached. In this embodiment, the first shaft 32 is driven to rotate, and thereby the strip-shaped sheet 20 is unwound from the unwinding roll 22 attached to the first shaft 32.

[0018] A space surrounded by the outer wall 30a of the unwinding section 30 is provided with a plurality of rollers 34 that set a transport path for the workpiece 20. The workpiece 20 unwound from the unwinding roll 22 attached to the first shaft 32 is passed around the plurality of rollers 34 in a predetermined order and transported toward the first heating section 40. The plurality of rollers 34 include a guide roller 34a, a tension detection roller 34b, a feed roller 34c, and a dancer roller 34d. The tension detection roller 34b is a roller for detecting the tension applied to the workpiece 20. A tension detector (not shown) is attached to the tension detection roller 34b. The dancer roller 34d is configured to be movable within a predetermined range. The tension of the workpiece 20 is adjusted by the movement of the dancer roller 34d. The feed roller 34c is rotationally driven by a transport device (not shown). The position of the dancer roller 34d is adjusted by controlling the rotation of the feed roller 34c.

[0019] The unwinding section 30 is connected to the first heating section 40 via a connecting section 90. The connecting section 90 has an outlet of the unwinding section 30 and an inlet of the first heating section 40. The workpiece 20 is transported to the first heating section 40 through the connecting section 90.

[0020] <First heating section 40> The first heating section 40 is a section where the workpiece 20 is heat-treated by laser heating. As shown in Fig. 3, the first heating section 40 is equipped with a laser device 42. In the first heating section 40, the workpiece 20 unwound from the unwind roll 22 is heat-treated by the laser device 42 while being conveyed.

[0021] 4 is a graph showing the temperature change of the workpiece 20. In FIG. 4, the solid line shows the temperature change of the workpiece 20 in the heat treatment apparatus 10 in which laser heating is performed in the first heating section and infrared heating is performed in the second heating section 50. In addition, in FIG. 4, the dashed line shows the temperature change of the workpiece in the heat treatment apparatus in which infrared heating is performed in both the first heating section and the second heating section. As shown in FIG. 4, the workpiece 20 is heated to a predetermined set temperature by the laser device 42 in the first heating section 40. The set temperature can be set appropriately depending on the configuration of the workpiece 20 to be treated, etc.

[0022] As shown in FIG. 3 , the first heating section 40 includes an outer wall 40a and a plurality of support rollers 44. In this embodiment, a transport space in which the workpiece 20 is transported and which is isolated from the outside is formed inside the outer wall 40a. The outer wall 40a surrounds the space in which the plurality of support rollers 44 are disposed. The laser device 42 is disposed outside the outer wall 40a. The first heating section 40 may be provided with a cover 40b that surrounds the outer wall 40a and the laser device 42. The space outside the outer wall 40a and inside the cover 40b is isolated from the space in which the workpiece 20 is transported, and the laser device 42 is disposed therein. In this embodiment, the space outside the outer wall 40a and inside the cover 40b is in communication with the outside and is an atmospheric pressure environment.

[0023] In this embodiment, the transport path of the workpiece 20 in the first heating section 40 is set to be linear along the front-to-rear direction. The workpiece 20 is supported by a plurality of support rollers 44. Note that the transport path in the first heating section 40 is not limited to being linear, and may be, for example, folded back within the first heating section 40. In addition to the support rollers 44, guide rollers or the like that set the transport path of the workpiece 20 may also be provided within the first heating section 40.

[0024] <Support Rollers 44> The support rollers 44 are rollers that support the workpiece 20 being transported within the first heating section 40. The support rollers 44 are cylindrical rollers. The support rollers 44 are aligned in the front-to-rear direction at a predetermined pitch. The multiple support rollers 44 are aligned at approximately the same height. The upper ends of the multiple support rollers 44 are positioned so that they are at approximately the same height as the upper end of the guide roller 34a (see FIG. 1) near the exit of the unwinding section 30. As a result, the workpiece 20 being transported from the unwinding section 30 is transported approximately horizontally forward.

[0025] In this embodiment, the support rollers 44 support the workpiece 20 from the second surface 20b. By being supported by the support rollers 44, the deflection of the workpiece 20 due to the weight of the workpiece 20 itself can be reduced. As a result, the laser can be more easily focused during heating, and uneven heating in the surface direction can be reduced.

[0026] <Laser Device 42> The laser device 42 is a device that irradiates the workpiece 20 with a laser to heat it. The workpiece 20 is heated by the laser device 42, causing the temperature to rise rapidly (see FIG. 4). In this embodiment, a semiconductor laser including an element formed of a semiconductor is used as the laser device 42. The laser device 42 includes an oscillator 42a, a transmission fiber 42b, and a processing head 42c. The processing head 42c is connected to the laser device 42 via the transmission fiber 42b. The laser device 42 is configured to be able to irradiate laser light P from the processing head 42c. The direction of the processing head 42c is set so that the optical axis of the laser light P is incident approximately perpendicularly on the sheet-like workpiece 20.

[0027] The processing head 42c of the laser device 42 is disposed outside the outer wall 40a. In this embodiment, the processing head 42c of the laser device 42 is disposed above the first heating section 40. The processing head 42c faces downward. At least the ceiling portion of the outer wall 40a may be provided with a window 40a1 that transmits the laser light P. The window 40a1 that transmits the laser light P may be made of, for example, quartz glass. The laser light P irradiated from the processing head 42c passes through the window 40a1. Within the first heating section 40, the workpiece 20 is irradiated with the laser light P, and the workpiece 20 is heated. In this embodiment, the laser light P is applied to the first surface 20a of the workpiece 20, which is opposite the second surface 20b supported by the support rollers 44. The periphery of the processing head 42c is shielded by a shielding plate 40c, except for the surface facing the quartz glass.

[0028] The laser device 42 may be a device that sets a two-dimensional irradiation area on the workpiece 20. In this embodiment, the laser device 42 is a device that can irradiate the workpiece 20 with a substantially rectangular laser beam P in a substantially uniform manner in the in-plane direction. The irradiation area of ​​the laser beam P may be set by adjusting the distance between the irradiated surface of the workpiece 20 and the processing head 42c, for example, by adjusting the height of the processing head 42c. The irradiation area of ​​the laser beam P may be set by an optical system unit 42c1 in the processing head 42c. The irradiation width of the laser beam P can be adjusted by adjusting the optical system unit 42c1. The irradiation width of the laser beam P increases from the processing head 42c toward the workpiece 20. The laser device 42 may be, for example, a semiconductor laser manufactured by Laserline. By irradiating and heating the workpiece 20 with the laser beam P in a substantially uniform manner over a wide area in the in-plane direction, the heating conditions (temperature rise conditions) can be maintained substantially constant in the in-plane direction of the workpiece 20. As a result, the quality of the processed workpiece 20 can be improved. From this perspective, compared to a laser device that locally heats the workpiece 20, it is preferable to use, as the laser device 42, a device in which an irradiation area is set along at least the width direction of the workpiece 20, and it is more preferable to use a device in which an irradiation area is set along the surface direction of the workpiece 20. The irradiation area of ​​the laser light P can be determined appropriately depending on the dimensions of the workpiece 20.

[0029] The number of laser devices 42 is not particularly limited and may be one or two or more. The number of laser devices 42 can be appropriately set depending on the processing conditions, transport conditions, etc. of the workpiece 20. In this embodiment, two laser devices 42 are provided in the first heating section 40. The processing heads 42c of the two laser devices 42 are aligned along the transport path. This can improve the heating efficiency of the workpiece 20. Furthermore, the heating conditions can be changed along the transport path, thereby improving the flexibility of the heat treatment. When multiple laser devices 42 are used in the first heating section 40, the laser devices 42 may be aligned along the transport direction or along the width direction of the workpiece 20. By aligning the laser devices 42 along the width direction of the workpiece 20, a wide irradiation area can be secured. The multiple laser devices 42 may be arranged so that the irradiation areas of each laser device 42 overlap. Alternatively, the multiple laser devices 42 may be aligned along the transport direction but at offset positions in the width direction. This allows the irradiation areas of the multiple laser devices 42 to overlap in the width direction, thereby reducing the difference in thermal history in the width direction of the workpiece 20. For example, the multiple laser devices 42 may be arranged alternately on the left and right along the conveyance direction.

[0030] When multiple laser devices 42 are used in the first heating unit 40, the irradiation areas of each laser device 42 may be separated from each other or may overlap. The arrangement of the laser devices 42 is not particularly limited. The laser devices 42 may be arranged so as to be able to heat from the second surface 20b, or may be arranged so as to be able to heat from both the first surface 20a and the second surface 20b.

[0031] The first heating section 40 is connected to the second heating section 50 via a connecting section 91. The connecting section 91 has an outlet of the first heating section 40 and an inlet of the second heating section 50. The workpiece 20 whose temperature has been raised to the set temperature is transported to the second heating section 50 through the connecting section 91.

[0032] <Second heating section 50> The second heating section 50 is a section that heats the workpiece 20 that has been heated in the first heating section 40 by a method other than laser heating. In the second heating section 50, the workpiece 20 is heat-treated under conditions different from those in the first heating section 40. In this embodiment, in the second heating section 50, the workpiece 20 is heated to the set temperature in the first heating section 40 and maintained at that temperature (see FIG. 4). This dries the workpiece 20.

[0033] In this embodiment, the second heating section 50 includes a heating device 52, guide rollers 54a to 54d, and an outer wall 50a. In this embodiment, a transport space in which the workpiece 20 is transported and which is isolated from the outside is formed inside the outer wall 50a. The outer wall 50a surrounds the space in which the heating device 52 and the guide rollers 54a to 54d are arranged.

[0034] <Guide Rollers 54a-54d> The guide rollers 54a-54d are rollers for setting a transport path along which the workpiece 20 is transported in the second heating section 50. In this embodiment, the guide rollers 54a-54d are cylindrical rollers. The axes of the guide rollers 54a-54d are oriented in the left-right direction. The guide roller 54a is provided near the entrance (connecting portion 91) of the second heating section 50. The upper end of the guide roller 54a is positioned at approximately the same height as the upper end of the support roller 44 of the first heating section 40. This allows the workpiece 20 to be transported approximately horizontally from the first heating section 40 to the second heating section 50. The multiple guide rollers 54b are arranged in order in the front-to-rear direction below the second heating section 50 at a predetermined pitch. The multiple guide rollers 54c are arranged above the second heating section 50, from the entrance to the exit of the second heating section 50, offset by a half pitch from the multiple guide rollers 54b. Guide roller 54d is provided near the exit (connecting portion 92) of second heating section 50. Workpiece 20 is hooked around guide roller 54a near the entrance of second heating section 50 and transported downward. Then, workpiece 20 is alternately looped around upper and lower guide rollers 54b and 54c in order from rear to front. As a result, workpiece 20 in second heating section 50 moves back and forth from the entrance to the exit. Then, workpiece 20 is hooked around guide roller 54d provided near the exit and transported toward cooling section 60.

[0035] <Heating Device 52> The heating device 52 is a device for heating the workpiece 20 by a method other than laser heating. Various devices capable of heating the workpiece 20 by a method that does not use laser light with uniform wavelengths can be used as the heating device 52. In this embodiment, an infrared heating device is used as the heating device 52. By using an infrared heating device, the workpiece 20 can be heat-treated regardless of the atmosphere in the second heating section 50. Furthermore, the heating device 52 has good heat uniformity efficiency in the surface direction of the workpiece 20. Here, the heating device 52 is a far-infrared plate heater. Various heaters can be used as the heating device 52 depending on the heating temperature, heating atmosphere, etc. In addition to a plate heater, for example, a cylindrical heater may also be used as the heating device 52. The material of the heating device 52 is not particularly limited, and a metal sheath heater, a ceramic heater, a lamp heater, etc. may also be used. Furthermore, the heating device 52 is not limited to a far-infrared heater. In the case of an atmospheric furnace, the heating device 52 may be, for example, a hot air heater that blows hot air onto the workpiece.

[0036] In this embodiment, the heating device 52 is disposed around the workpiece 20, which is hung on guide rollers 54a to 54d and moves back and forth up and down while proceeding from the entrance to the exit, so as to face the workpiece 20. The heating device 52 is disposed around the guide rollers 54b and 54c and faces the workpiece 20 in the gaps between the workpieces 20 that move back and forth up and down, or around the workpieces 20 being transported. The heating device 52 may be fixed by, for example, a holder and a support. A support for fixing the holder may be erected on the bottom wall of the outer wall 50a. A holder may be fixed to the support. The heating device 52 may also be fixed by a holder. The heating device 52 may also be supported by, for example, the side wall of the outer wall 40a (see FIG. 3).

[0037] The guide rollers 54a to 54d are arranged as described above, thereby increasing the distance over which the workpiece 20 is transported in the second heating section 50. The transport path set in the second heating section 50 is thus longer than the transport path set in the first heating section 40. This allows the workpiece 20 to be dried efficiently. Furthermore, heat from the heating device 52 is applied equally to the first surface 20a and the second surface 20b of the workpiece 20. This allows the heating conditions of the first surface 20a and the second surface 20b of the workpiece 20 to be similar. This reduces the difference in thermal history between the first surface 20a and the second surface 20b of the workpiece 20. The thermal history is the history of the workpiece 20 being heated and cooled. By matching the heating and cooling conditions within the workpiece 20, the difference in thermal history within the workpiece 20 can be reduced.

[0038] The arrangement of the heating device 52 and the guide rollers 54a to 54d is not limited to this. The arrangement of the heating device 52 and the guide rollers 54a to 54d may be set appropriately depending on the type of workpiece 20, the heat treatment conditions, etc. For example, in a case where the first surface 20a and the second surface 20b of the workpiece 20 are formed of different materials, the arrangement, output, etc. of the heating device 52 may be set so that the first surface 20a and the second surface 20b are heat treated under different conditions.

[0039] The second heating section 50 is connected to the cooling section 60 via a connecting section 92. The connecting section 92 has an outlet of the second heating section 50 and an inlet of the cooling section 60. The workpiece 20 maintained at the set temperature is transported to the cooling section 60 through the connecting section 92.

[0040] <Cooling Section 60> The cooling section 60 is a section where the workpiece 20, which has been heat-treated in the second heating section 50, is cooled while being transported. By providing the cooling section 60, the workpiece 20 can be wound around the take-up roll 24 while its temperature is reduced. The cooling section 60 is particularly effective when the processing temperature of the workpiece 20 in the first heating section 40 and the second heating section 50 is high. The cooling section 60 includes a cooling roller 62, multiple guide rollers 68, and an outer wall 60a. In this embodiment, a transport space is formed inside the outer wall 60a through which the workpiece 20 is transported and which is isolated from the outside. In this embodiment, the cooling section 60 includes multiple cooling rollers 62. The multiple cooling rollers 62 and the multiple guide rollers 68 define a transport path along which the workpiece 20 is transported in the cooling section 60. While a single cooling roller 62 may be provided, multiple cooling rollers 62 are preferred.

[0041] <Cooling Roller 62> The cooling roller 62 is configured to allow a refrigerant to flow therethrough. In this embodiment, the cooling roller 62 includes at least one first cooling roller 62a and at least one second cooling roller 62b. The first cooling roller 62a is a cooling roller 62 that is wound around the first surface 20a of the workpiece 20 so as to contact the first cooling roller 62a. The second cooling roller 62b is a cooling roller 62 that is wound around the second surface 20b of the workpiece 20 so as to contact the second cooling roller 62b. In this embodiment, the cooling roller 62 is connected to a drive unit (not shown). The cooling roller 62 rotates along the conveying direction at a set conveying speed. In this embodiment, the workpiece 20 is cooled to approximately room temperature in the cooling section 60 (see FIG. 4). The temperature of the cooled workpiece 20 is not particularly limited.

[0042] In this embodiment, a plurality of first cooling rollers 62 a and a plurality of second cooling rollers 62 b (four of each) are provided. The number of cooling rollers 62 is not particularly limited. For example, one of each of the first cooling roller 62 a and the second cooling roller 62 b may be provided.

[0043] In this embodiment, the multiple first cooling rollers 62a are arranged in a row at a predetermined pitch along the height direction in front of (the exit side of) the cooling unit 60. The multiple second cooling rollers 62b are arranged in a row at a predetermined pitch along the height direction in the rear of (the entrance side of) the cooling unit 60. The interval between adjacent first cooling rollers 62a and the interval between adjacent second cooling rollers 62b are each set to be narrower than the outer diameter of the cooling roller 62. The arrangement of the first cooling rollers 62a and the second cooling rollers 62b is not particularly limited. For example, the multiple first cooling rollers 62a and the multiple second cooling rollers 62b may each be arranged from the entrance side to the exit side of the cooling unit 60. The multiple first cooling rollers 62a may be arranged in a row above the cooling unit 60 at a predetermined pitch. The multiple second cooling rollers 62b may be arranged in a row below the cooling unit 60 at a predetermined pitch. The interval between adjacent first cooling rollers 62 a and the interval between adjacent second cooling rollers 62 b may be set to be wider than the outer diameter of the cooling rollers 62 .

[0044] In this embodiment, the first cooling rollers 62a and the second cooling rollers 62b are arranged at the same pitch, and the height of the second cooling rollers 62b is arranged half a pitch higher than the first cooling rollers 62a, starting from the bottom. As a result, the multiple first cooling rollers 62a and the multiple second cooling rollers 62b are arranged so that their heights are shifted sequentially before and after the cooling unit 60. In other words, the multiple first cooling rollers 62a and the multiple second cooling rollers 62b are arranged in a staggered pattern. By arranging the first cooling rollers 62a and the second cooling rollers 62b in this manner, the cooling unit 60 can be made elongated in the height direction. On the other hand, the area occupied by the cooling unit 60 can be reduced, thereby saving space in the equipment.

[0045] <Guide Rollers 68> The guide rollers 68 are rollers that guide the workpieces 20. In this embodiment, the guide rollers 68 are cylindrical rollers. The axes of the guide rollers 68 are provided in the cooling section 60 and oriented in the left-right direction. In the cooling section 60, a transport path for the workpieces 20 is set by the plurality of guide rollers 68 so that the workpieces 20 travel from the entrance (connecting section 92) through the plurality of cooling rollers 62, and from the plurality of cooling rollers 62 to the exit (connecting section 93). The plurality of guide rollers 68 includes a tension detection roller that detects the tension applied to the workpieces 20.

[0046] The workpiece 20 is introduced into the cooling section 60 from the entrance thereof through the guide roller 68a and is conveyed downward on the upstream side of the plurality of cooling rollers 62. The workpiece 20 is conveyed through the guide roller 68b to the first cooling roller 62a, which is located at the lowest end. The workpiece 20 is alternately wound around the first cooling roller 62a and the second cooling roller 62b, starting from the bottom, and conveyed from the second cooling roller 62b, which is located at the top, toward the guide roller 68c. The workpiece 20 is conveyed downward through the guide roller 68c and conveyed through the guide roller 68d from the exit of the cooling section 60 to the winding section 70. At this time, the workpiece 20 is wound around the first cooling roller 62a so that the first surface 20a of the workpiece 20 contacts the first cooling roller 62a and the second surface 20b of the workpiece 20 contacts the second cooling roller 62b. Therefore, the first surface 20a and the second surface 20b of the workpiece 20 are cooled in sequence by the cooling rollers 62. This reduces the difference in thermal history between the first surface 20a and the second surface 20b of the workpiece 20.

[0047] Cooling section 60 is connected to winding section 70 via connecting section 93. Connecting section 93 includes an outlet of cooling section 60 and an inlet of winding section 70. Cooled workpiece 20 is transported to winding section 70 through connecting section 93.

[0048] <Winding Section 70> The winding section 70 is a section that winds up the workpiece 20. As shown in FIG. 1 , the winding section 70 houses a winding roll 24 for winding up the workpiece 20 cooled by the cooling roller 62. The winding section 70 has an outer wall 70a that surrounds the internal equipment. In this embodiment, a transport space is formed inside the outer wall 70a, through which the workpiece 20 is transported and which is isolated from the outside. The winding section 70 is provided with a second shaft 72 and a plurality of rollers 74. The second shaft 72 is fitted with the winding roll 24 on which the workpiece 20, which has been heat-treated in the first heating section 40 and the second heating section 50 and cooled in the cooling section 60, is wound. The second shaft 72 is driven to rotate, thereby winding up the workpiece 20 onto the winding roll 24.

[0049] The rollers 74 define a transport path along which the workpiece 20 is transported in the winding section 70. The workpiece 20 transported from the cooling section 60 is hooked onto the rollers 74 near the entrance (connecting section 93) of the winding section 70, then looped around the rollers 74 in a predetermined order, and wound onto the winding roll 24. The rollers 74 include a guide roller 74a, a roller 74b, a tension detection roller 74c, and a feed roller 74d. The roller 74b is configured to be movable within a predetermined range. The roller 74b can be moved to ensure the necessary slack in the workpiece 20, for example, when the winding roll 24 is replaced. A tension detector (not shown) is attached to the tension detection roller 74c. The feed roller 74d feeds out the slack required for attaching the workpiece 20 to the replaced winding roll 24 when replacing the winding roll 24.

[0050] The present inventors have been studying ways to improve the processing efficiency of strip-shaped workpieces. For example, the processing efficiency can be improved by increasing the transport speed of the workpieces. However, when the transport speed of the workpieces is increased, the speed at which the workpieces pass through the heating section increases. Since the temperature rise rate of the workpieces remains unchanged, in order to heat the workpieces to the set temperature, the transport path within the heating section must be lengthened as the transport speed increases. In order to lengthen the transport path within the heating section, an increase in the size of the equipment is required. Furthermore, the energy cost required to heat the workpieces also increases.

[0051] In the embodiment described above, the heat treatment apparatus 10 includes transport devices 80, 82, a first heating section 40, and a second heating section 50. The transport devices 80, 82 transport the strip-shaped workpiece 20 along a predetermined transport path. The first heating section 40 includes a laser device 42 that irradiates the workpiece 20 with laser light P to heat it. The second heating section 50 includes a heating device 52 that heats the workpiece 20 heated in the first heating section 40 by a method other than laser heating.

[0052] In this heat treatment apparatus 10, the workpiece 20 is heated by the laser device 42 in the first heating section 40 before being maintained at a set temperature in the second heating section 50. By using the laser device 42, which allows setting the irradiation area of ​​the laser light P, it is possible to efficiently heat the desired area of ​​the workpiece 20. This makes it possible to heat the workpiece 20 while minimizing energy loss. For example, as shown in FIG. 4, the temperature rise rate of the workpiece 20 can be improved compared to when the workpiece is heated using only infrared heating. Furthermore, the transport path in the first heating section 40 for raising the temperature of the workpiece 20 can be shortened, allowing for a more compact facility.

[0053] According to the inventor's findings, laser heating provides a large amount of energy to the workpiece 20 per unit time, causing the workpiece 20 to heat up rapidly. This can result in temperature variations across the surface of the workpiece 20. In the embodiment described above, the laser-heated workpiece 20 is heated by the heating device 52 in the second heating section 50. This allows the laser-heated workpiece 20, whose temperature has risen rapidly, to be heated by a method other than laser heating, which facilitates uniform heating during transport within the second heating section 50. This results in good quality of the workpiece 20 after heat treatment in the first heating section 40 and the second heating section 50. The heat treatment device 10 disclosed herein can efficiently treat the workpiece 20 while maintaining its quality.

[0054] In the above-described embodiment, the transport path set in the second heating section 50 is longer than the transport path set in the first heating section 40. In this heat treatment apparatus 10, the equipment of the first heating section 40 is miniaturized. In the second heating section 50, the transport path is set long, which makes it easier to uniformly heat the workpiece 20, and can improve the quality of the workpiece 20 after processing.

[0055] In the above-described embodiment, a transport space in which the workpiece 20 is transported and which is isolated from the outside is formed in the unwinding section 30, the first heating section 40, the second heating section 50, the cooling section 60, and the winding section 70. This allows the workpiece 20 to be processed in a space isolated from the outside, making it possible to stabilize the processing conditions. Furthermore, the atmosphere in the transport space can be controlled to an atmosphere according to the processing purpose of the workpiece 20.

[0056] In this embodiment, as shown in FIG. 1 , the heat treatment apparatus 10 includes a vacuum pump 12 for reducing the pressure in the transfer space. The vacuum pump 12 is connected to the unwinding section 30, the first heating section 40, the second heating section 50, the cooling section 60, and the winding section 70. The workpiece 20 is treated under a predetermined vacuum atmosphere lower than atmospheric pressure. The connection configuration of the vacuum pump 12 is not limited to this. For example, the unwinding section 30, the first heating section 40, the second heating section 50, the cooling section 60, and the winding section 70 may be configured to reduce the internal pressure by multiple vacuum pumps 12. For example, multiple vacuum pumps 12 may be connected to each section. Treating the workpiece 20 under a reduced pressure environment improves the drying efficiency of the workpiece 20 and improves the treatment efficiency of the workpiece 20. Doors 90a and 93a are provided at the entrance of the first heating section 40 (connecting section 90 in this embodiment) and the exit of the cooling section 60 (connecting section 93 in this embodiment), respectively.

[0057] The piping of the vacuum pump 12 is provided with vacuum valves 12a to 12e for adjusting the degree of vacuum in each section. The vacuum valves 12a to 12e are configured to be able to switch between connecting and disconnecting each section from the vacuum pump 12. When the degree of vacuum in each section is not to be adjusted, an on-off valve may be used instead of the vacuum valves 12a to 12e. In this embodiment, the degree of vacuum in the transfer space is controlled by a control device 15. Note that the transfer space may be controlled by a device separate from the control device 15.

[0058] The control device 15 is connected to the vacuum pump 12 and the vacuum valves 12a to 12e so as to be able to adjust the degree of vacuum in each part. The control device 15 may also be connected to a vacuum detector (not shown) for detecting the degree of vacuum in each part. When the workpiece 20 is treated in the heat treatment device 10, the vacuum valves 12a to 12e are opened. During steady-state operation, the doors 90a and 93a are open, and the degree of vacuum in each part is the same.

[0059] When a roll is replaced, the control device 15 controls the opening and closing of each of the vacuum valves 12a to 12e, thereby switching the vacuum level in each section. When the unwinding roll 22 is replaced, the vacuum valve 12a is closed with the door 90a closed. This allows the atmosphere in the first heating section 40 to be maintained, and the device can be restored quickly after replacing the unwinding roll 22. When the take-up roll 24 is replaced, the vacuum valve 12e is closed with the door 93a closed. This allows the atmosphere in the cooling section 60 to be maintained, and the device can be restored quickly after replacing the unwinding roll 22. When a roll is replaced, the room in which the roll is replaced is opened to the atmosphere by an air release valve (not shown). Air release valves may also be provided in the first heating section 40, the second heating section 50, and the cooling section 60. The control device 15 can control the opening and closing of the vacuum valves 12a to 12e and the air release valve during heating treatment or roll replacement.

[0060] The heat treatment apparatus 10 may be an atmosphere furnace that heat-treats the workpiece 20 in a predetermined atmosphere. Even when the heat treatment apparatus 10 is an atmosphere furnace, the workpiece 20 can be efficiently treated while maintaining quality, as described above. When the heat treatment apparatus 10 is an atmosphere furnace, the heat treatment apparatus 10 may further include a supply device that supplies a predetermined gas to the transfer space. The supply device may be composed of a gas cylinder or the like for supplying the atmosphere gas. Examples of the atmosphere gas that can be used include nitrogen, argon, air, oxygen, carbon dioxide, and hydrogen. The atmosphere gas is selected appropriately depending on the heating conditions of the workpiece. The heat treatment apparatus 10 may also be connected to an exhaust device such as an exhaust pump that exhausts gas from the transfer space.

[0061] <First Heating Unit 40A> FIG. 5 is a schematic diagram showing a first heating unit 40A according to another embodiment. In the embodiment shown in FIG. 5, the first heating unit 40 includes a temperature detection device 46 and an output control device 48. The temperature detection device 46 detects the temperature of the workpiece 20 heated by the laser device 42. An infrared thermometer, for example, may be used as the temperature detection device 46. The output control device 48 controls the output of the laser device 42. The output control device 48 may be connected to the temperature detection device 46 and the oscillator 42a. The output control device 48 controls the output of the laser device 42 based on the temperature detected by the temperature detection device 46. The output control device 48 may control the output of the laser device 42 so as to reduce the output of the laser device 42 when the temperature detected by the temperature detection device 46 is higher than a set value, and to increase the output of the laser device 42 when the temperature detected by the temperature detection device 46 is lower than the set value. The set value that serves as a reference for increasing the output and the set value that serves as a reference for decreasing the output do not have to be the same. The set value that is the reference for increasing the output may be lower than the set value that is the reference for decreasing the output.

[0062] The temperature detecting device 46 may be configured to detect the temperature at a plurality of points in the width direction of the workpiece 20. A plurality of temperature detecting devices 46 may be provided along the width direction of the workpiece 20. When the temperature detecting device 46 detects a temperature difference in the width direction of the workpiece 20, the output control device 48 may control the output of the laser device 42 in the width direction. For example, when a plurality of laser devices 42 are lined up along the width direction of the workpiece 20, the output control device 48 may control the output of the laser device 42 so as to reduce the temperature difference in the width direction of the workpiece 20.

[0063] Although the present invention has been described in detail above using specific embodiments, these are merely examples and do not limit the scope of the claims. Thus, the technology described in the claims includes various modifications and alterations of the above-described embodiments.

[0064] This specification includes the following items 1 to 9. The following items 1 to 9 are not limited to the above-described embodiments.

[0065] Item 1: A heat treatment apparatus comprising: a transport device that transports a strip-shaped workpiece along a predetermined transport path; a first heating section having a laser device that irradiates and heats the workpiece with laser light; and a second heating section having a heating device that heats the workpiece heated in the first heating section by a method other than laser heating.

[0066] Item 2: The heat treatment apparatus according to Item 1, wherein the laser device has an irradiation area set along at least the width direction of the object to be treated.

[0067] Item 3: The heat treatment apparatus according to item 1 or 2, wherein a transport path set in the second heating unit is longer than a transport path set in the first heating unit.

[0068] Item 4: The heat treatment device according to any one of Items 1 to 3, wherein the heating device is an infrared heating device.

[0069] Item 5: The heat treatment device according to any one of Items 1 to 4, further comprising: an unwinding section that unwinds the workpiece; and a winding section that winds the treated workpiece, wherein the unwinding section, the first heating section, the second heating section, and the winding section form a transport space through which the workpiece is transported and which is isolated from the outside.

[0070] Item 6: The heat treatment apparatus according to Item 5, further comprising a vacuum pump that reduces the pressure in the transfer space.

[0071] Item 7: A heat treatment device according to any one of items 1 to 6, wherein the first heating section includes a temperature detection device that detects the temperature of the workpiece heated by the laser device, and an output control device that controls the output of the laser device based on the temperature detected by the temperature detection device.

[0072] Item 8: The heat treatment apparatus according to Item 5, further comprising a supply device that supplies a predetermined gas to the transfer space.

[0073] Item 9: A method for heat treating an object to be treated, comprising: a first heating step of irradiating a band-shaped object to be treated that is being transported along a predetermined transport path with laser light to heat it; and a second heating step of heating the object to be treated that has been heated in the first heating step and is being transported along the transport path by a method other than a laser.

Claims

1. A heat treatment apparatus comprising: a transport device that transports a strip-shaped workpiece along a predetermined transport path; a first heating section having a laser device that irradiates the workpiece with laser light to heat it; and a second heating section having a heating device that heats the workpiece heated in the first heating section by a method other than laser heating.

2. The heat treatment apparatus according to claim 1, wherein the laser device has an irradiation area set along at least the width direction of the workpiece.

3. The heat treatment apparatus according to claim 1 or 2, wherein a transport path set in the second heating section is longer than a transport path set in the first heating section.

4. The heat treatment apparatus according to claim 1 or 2, wherein the heating device is an infrared heating device.

5. A heat treatment apparatus as described in claim 1 or 2, further comprising: an unwinding section which unwinds the workpiece; and a winding section which winds up the treated workpiece, wherein a transport space is formed between the unwinding section, the first heating section, the second heating section, and the winding section, through which the workpiece is transported and which is isolated from the outside.

6. The heat treatment apparatus according to claim 5, further comprising a vacuum pump for reducing the pressure in the transfer space.

7. A heat treatment device as described in claim 1 or 2, wherein the first heating section is provided with a temperature detection device that detects the temperature of the workpiece heated by the laser device, and an output control device that controls the output of the laser device based on the temperature detected by the temperature detection device.

8. The heat treatment apparatus according to claim 5, further comprising a supply device for supplying a predetermined gas to said transfer space.

9. A method for heating a workpiece, comprising: a first heating step of irradiating a band-shaped workpiece transported along a predetermined transport path with laser light to heat the workpiece; and a second heating step of heating the workpiece, which is transported along the transport path and has been heated in the first heating step, by a method other than a laser.

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