Film removal method and film removal device

Abstract

This film removal method comprises: a first step of arranging an optical head and a workpiece including a base material that is made of, for example, a metal material, a first film that is made of a synthetic resin material and covers the surface of the base material directly or indirectly with another film interposed therebetween, and a second film that is made of a synthetic resin material having a lower absorption rate of laser light than the synthetic resin material constituting the first film and covers the first film on the side opposite to the surface of the base material, in a predetermined positional relationship so that laser light that is output from the optical head is irradiated onto the surface of the workpiece; and a second step of, after the first step, irradiating the workpiece while scanning the laser light from the optical head, and separating the first film and the second film by causing a change in the first film by the laser light that is transmitted through the second film.

Description

Coating removal method and coating removal device

[0001] The present invention relates to a coating removal method and a coating removal device.

[0002] BACKGROUND ART Conventionally, a coating removal method and a coating removal device are known that remove a coating covering a base material by irradiating the base material with laser light to expose the base material (Patent Document 1).

[0003] JP 2017-220634 A

[0004] In this type of coating removal method, it would be beneficial to have an improved new coating removal method that would enable more efficient coating removal even from workpieces whose base material is covered with multiple coatings made of synthetic resin materials.

[0005] Therefore, one object of the present invention is to provide, for example, an improved novel coating removal method and coating removal device.

[0006] The coating removal method of the present invention includes a first step of arranging an object to be processed, which has, for example, a base material made of a metal material, a first coating made of a synthetic resin material and covering the surface of the base material directly or indirectly via another coating, and a second coating made of a synthetic resin material that covers the first coating on the opposite side of the surface of the base material and has a lower laser light absorption rate than the synthetic resin material constituting the first coating, and an optical head in a predetermined positional relationship so that the laser light output from the optical head is irradiated onto the surface of the object to be processed; and a second step of, after the first step, irradiating the laser light from the optical head onto the object to be processed while scanning it, and separating the first coating from the second coating by causing a change in the first coating with the laser light that has passed through the second coating.

[0007] In the coating removal method, in the second step, a space may be formed between the first coating and the second coating by irradiating the laser light that has passed through the second coating.

[0008] In the coating removal method, in the second step, the first coating may be foamed by irradiating the laser light that has passed through the second coating.

[0009] In the coating removal method, in the second step, the power density of the laser light may be less than the power density at which the first coating is carbonized and equal to or greater than the power density at which the first coating is melted or vaporized.

[0010] In the coating removal method, the wavelength of the laser light may be equal to or greater than 400 [nm] and equal to or less than 550 [nm].

[0011] In the coating removal method, the laser light may include blue laser light.

[0012] In the coating removal method, in the second step, the laser light may be a continuous wave laser light.

[0013] The coating removal method may include a third step of cutting the second coating to separate the second coating into a portion that is separated from the first coating and a portion that is not separated from the first coating.

[0014] In the coating removal method, in the second step, a space is formed between the first coating and the second coating by irradiating the laser light that has passed through the second coating, and in the third step, the second coating may be cut at a position that is a boundary between a region where the space is formed and the second coating has peeled off from the first coating, and a region where the second coating has not peeled off from the first coating.

[0015] In the coating removal method, the cutting may be performed by irradiating with laser light in the third step.

[0016] In the coating removal method, the third step may be performed after the second step.

[0017] In the coating removal method, the third step may be performed before the second step.

[0018] The film removal method may include a fourth step of removing the first film remaining in the second step by irradiating the laser light from the optical head.

[0019] A coating removal method of the present invention includes, for example, a laser device that outputs laser light, and an optical head that irradiates the laser light output from the laser device while scanning it over the surface of an object to be processed, wherein the object to be processed has a base material made of a metal material, a first coating made of a synthetic resin material that covers the surface of the base material directly or indirectly via another coating, and a second coating that covers the side of the first coating opposite the surface and is made of a synthetic resin material that has a lower absorption rate for the laser light than the synthetic resin material that constitutes the first coating, and the first coating and the second coating are separated by causing a change in the first coating by the laser light that has passed through the second coating.

[0020] According to the present invention, for example, a novel and improved coating removal method and coating removal device can be provided.

[0021] FIG. 1 is an exemplary schematic diagram of a film removal device according to an embodiment. FIG. 2 is an exemplary and schematic cross-sectional view of a rectangular wire as a processing target of the film removal device according to an embodiment. FIG. 3 is a graph showing the light absorption rate of a synthetic resin material versus the wavelength of light when light is irradiated onto the synthetic resin material. FIG. 4 is an exemplary and schematic cross-sectional view showing an initial state of a step of separating a second film from a first film in the film removal method according to an embodiment. FIG. 5 is an exemplary and schematic cross-sectional view showing an almost completed state of a step of separating a second film from a first film in the film removal method according to an embodiment. FIG. 6 is an exemplary and schematic cross-sectional view showing an initial state of a step of separating a second film between a portion separated from the first film and a portion not separated from the first film in the film removal method according to an embodiment. FIG. 7 is an exemplary and schematic cross-sectional view showing an almost completed state of a step of separating a second film between a portion separated from the first film and a portion not separated from the first film in the film removal method according to an embodiment. Fig. 8 is an exemplary schematic cross-sectional view showing a state in which the step of separating the second film into a portion separated from the first film and a portion not separated from the first film in the film removal method of the embodiment is almost completed, in which the boundary and the cutting line are different. Fig. 9 is a schematic plan view showing an example of a laser light scanning pattern, a laser light irradiation area, a boundary between a peeled portion and a non-peeled portion, and a cutting line in the second step of the film removal method of the embodiment. Fig. 10 is a schematic plan view showing an example of a laser light scanning pattern, a laser light irradiation area, a boundary between a peeled portion and a non-peeled portion, and a cutting line in the second step of the film removal method of the embodiment. Fig. 11 is a schematic plan view showing an example of a laser light scanning pattern, a laser light irradiation area, a boundary between a peeled portion and a non-peeled portion, and a cutting line in the second step of the film removal method of the embodiment. Fig. 12 is a schematic plan view showing an example of a laser light scanning pattern, a laser light irradiation area, a boundary between a peeled portion and a non-peeled portion, and a cutting line in the second step of the film removal method of the embodiment. 13 is an exemplary schematic cross-sectional view showing a step of removing a portion of the second coating to be separated from the first coating in the coating removal method of the embodiment. FIG. 14 is an exemplary schematic cross-sectional view showing an initial state of a step of separating the first coating from the base material in the coating removal method of the embodiment.FIG. 15 is an exemplary schematic cross-sectional view showing a state in which the step of separating the first coating from the base material in the coating removal method according to the embodiment is substantially completed.

[0022] Exemplary embodiments and modifications of the present invention are disclosed below. The configurations of the embodiments and modifications shown below, as well as the actions and results (effects) brought about by these configurations, are merely examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments and modifications. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derivative effects) obtained by the configurations.

[0023] In each drawing, the X direction is represented by an arrow X, the Y direction is represented by an arrow Y, and the Z direction is represented by an arrow Z. The X direction, Y direction, and Z direction intersect with each other and are perpendicular to each other.

[0024] [Embodiment] [Laser Processing Apparatus] Fig. 1 is a schematic configuration diagram of a laser processing apparatus 100. As shown in Fig. 1, the laser processing apparatus 100 has a laser device 110, an optical head 120, and an optical fiber 130. The laser processing apparatus 100 is an example of a coating removal apparatus.

[0025] The laser device 110 is configured to be able to output laser light with a power of, for example, several kW, and includes a housing 110a, a laser module 110b, and a lens 110c.

[0026] The laser module 110b outputs a continuous wave laser beam with a wavelength of 400 nm or more and 550 nm or less. That is, the laser beam is a blue or green laser beam, and is a continuous wave laser. The laser module 110b has multiple laser elements. It may also be called a laser oscillator. An example of the laser module 110b that outputs blue laser beam is the BR0400 manufactured by Furukawa Electric Co., Ltd.

[0027] The lens 110c couples the laser light output from the laser module 110b to the optical fiber 130. That is, the laser module 110b is optically connected to the optical fiber 130 via the lens 110c. The lens 110c is, for example, a condenser lens. The lens 110c is an example of an optical component. Note that the laser device 110 may have an optical component other than the lens 110c.

[0028] The optical fiber 130 guides the laser light output from the laser device 110 to the optical head 120 .

[0029] The optical head 120 is an optical device for irradiating the laser light input from the laser device 110 toward the electric wire 10. The optical head 120 has a collimating lens 121, a condensing lens 122, a mirror 124, and a laser scanner 126. The collimating lens 121, the condensing lens 122, the mirror 124, and the laser scanner 126 may also be referred to as optical components.

[0030] The optical head 120 is configured to be able to change its position relative to the electric wire 10 in order to scan the laser light while irradiating the surface 10a of the electric wire 10 as the processing target. Note that scanning of the spot on the surface 10a may be achieved by at least one of movement of the optical head 120, movement of the electric wire 10, and change in the emission direction of the laser light beam from the optical head 120.

[0031] The collimating lens 121 collimates the laser light input via the optical fiber 130. The collimated laser light becomes parallel light.

[0032] Mirror 124 reflects the laser light that has been collimated by collimator lens 121. In the example of Fig. 1, the laser light reflected by mirror 124 travels in the opposite direction of the Z direction toward condenser lens 122. Note that in a configuration in which the laser light is input to optical head 120 so as to travel in the opposite direction of the Z direction, mirror 124 is not necessary.

[0033] The laser scanner 126 is, for example, a galvanometer scanner having multiple mirrors (not shown). The galvanometer scanner can switch the output direction of the laser light L from the optical head 120 by changing the angles of the multiple mirrors. The angles of the mirrors are changed by, for example, motors (neither of which is shown) controlled by the control device 140. The laser scanner 126 is an example of a scanning mechanism that scans a beam (spot) of laser light L on the surface 10a of the electric wire 10. Examples of the laser scanner 126 include the SProScan III manufactured by PdLaser, and the YD-3000 and YD-300 manufactured by Yaskawa Electric Corporation. Note that the optical head 120 may have a laser scanner 126 other than a galvanometer scanner.

[0034] The condensing lens 122 condenses the laser light as parallel light and irradiates it as laser light L (output light) to an irradiation point P on the surface 10a of the electric wire 10. The irradiation point P is an example of an irradiation position. The laser light L is output from the condensing lens 122, i.e., the optical head 120, toward the electric wire 10 in a direction substantially along the opposite direction to the Z direction.

[0035] The laser processing apparatus 100 also includes a drive mechanism 150 and a gas supply mechanism 160 .

[0036] The driving mechanism 150 changes the relative position of the optical head 120 with respect to the electric wire 10. The driving mechanism 150 has, for example, a rotation mechanism such as a motor, a speed reduction mechanism that reduces the rotation output of the rotation mechanism, and a motion conversion mechanism that converts the rotation reduced by the speed reduction mechanism into linear motion.

[0037] The gas supply mechanism 160 supplies gas G toward the irradiation point P through a pipe 161. The gas G is discharged at a predetermined flow rate from a nozzle outlet 161a provided at the tip of the pipe 161 and facing the irradiation point P. The laser processing apparatus 100 burns the coating and removes it from the electric wire 10 by irradiating the electric wire 10 with laser light L while supplying gas G. The gas G contains oxygen to promote the combustion of the coating of the electric wire 10. The gas G may be air. The supply of gas G containing oxygen promotes the combustion of the coating, so that the coating 12 can be removed more quickly and a higher quality processed state (exposed surface of the base material) with less residue can be obtained compared to when gas G is not supplied.

[0038] The laser processing apparatus 100 also includes a control device 140 that controls the operation of the laser device 110, the drive mechanism 150, and the gas supply mechanism 160. The control device 140 is, for example, a computer having a controller, a main memory unit, an auxiliary memory unit, etc.

[0039] The control device 140 can control the operation of the laser device 110, for example, to output laser light, stop output of laser light, or change the output intensity of laser light.

[0040] The control device 140 can control the operation of the drive mechanism 150, for example, so that the irradiation point P of the laser light on the electric wire 10 moves and the irradiation point P is scanned, that is, so that the relative position of the optical head 120 and the electric wire 10 changes. The drive mechanism 150 is an example of a scanning mechanism that scans the beam (spot) of the laser light L on the surface 10a of the electric wire 10.

[0041] Furthermore, the control device 140 can control the operation of the gas supply mechanism 160, for example, to supply the gas G, stop the supply of the gas G, or change the supply flow rate of the gas G.

[0042] The oxygen concentration in the gas G may be set according to the flammability of the coating material. Specifically, the higher the flammability of the coating material, the lower the oxygen concentration to be supplied, and the lower the flammability of the coating material, the higher the oxygen concentration to be supplied. The oxygen concentration is adjusted, for example, by a switching mechanism such as an electromagnetic valve that can change the discharge flow rate from the oxygen tank. This configuration and setting can achieve effects such as suppressing combustion of the coating beyond the intended range and achieving more efficient and rapid combustion. The oxygen concentration in the gas G is appropriately set within a range equal to or greater than the oxygen concentration in air and equal to or less than the oxygen concentration in pure oxygen. In this case, the oxygen concentration is the concentration at a fixed position, such as the tip of the nozzle of the piping 161.

[0043] [Processing Object] Fig. 2 is a cross-sectional view intersecting the longitudinal direction of an electric wire 10 as a processing object. As shown in Fig. 2, the electric wire 10 is, for example, a rectangular wire having a flattened rectangular cross section. The electric wire 10 has a conductor 11 as a base material having a belt-like and plate-like shape, and coatings 21 and 22 that surround the conductor 11 in multiple layers. The coating 21 directly covers the surface 11a of the conductor 11, and the coating 22 directly covers the surface 21a of the coating 21. The surface 22a of the coating 22 is the surface 10a of the electric wire 10. The coating 21 is an example of a first coating, and the coating 22 is an example of a second coating.

[0044] The conductor 11 is made of a metal material, such as, but not limited to, a copper-based material, such as oxygen-free copper or a copper alloy.

[0045] The coatings 21, 22 are made of an insulating synthetic resin material such as a resin having an imide group, such as polyimide or polyamideimide, or polyaryletherketone, polyetheretherketone, polyurethane, polyester, or polyesterimide. Synthetic resin materials may also be referred to as organic polymer materials. The thickness of the coatings 21, 22 may be set to various values, and the coatings 21, 22 may be a laminate of multiple layers.

[0046] 3 is a graph showing the change in absorption coefficient of three synthetic resin materials (polyimide, polyamideimide, and polyetheretherketone) depending on the wavelength of light. As shown in Fig. 3, in the wavelength range of 400 nm or more and 550 nm or less, polyetheretherketone has the lowest absorption coefficient, while polyamideimide has a higher absorption coefficient than polyetheretherketone, and polyimide has a higher absorption coefficient than polyamideimide.

[0047] The laser processing apparatus 100 (film removal apparatus) and film removal method of this embodiment are intended for a film that includes a portion where a film 21 made of a synthetic resin material is covered with a film 22 made of a synthetic resin material having a lower absorption coefficient (absorption rate) than the film 21. The procedure and technical concept for removing the films 21 and 22 will be described below.

[0048] 1, the optical head 120 and the electric wire 10 are positioned in a predetermined relative positional relationship so that the laser light L output from the optical head 120 is irradiated onto the surface 10a of the electric wire 10 (S1). S1 is an example of a first step.

[0049] Next, the procedure after S1 will be described with reference to Figures 4 to 10. Figures 4 to 10 are cross-sectional views of the electric wire 10 at each stage of the film removal procedure.

[0050] [Separation of First Coating and Second Coating] After S1, as shown in Figures 4 and 5, the laser light L1 from the optical head 120 is scanned and irradiated onto the area Ar of the electric wire 10 to be removed, thereby separating the coating 21 from the coating 22 in the area Ar (S2). Figure 4 shows the initial state of S2, and Figure 5 shows the state after step S2 is approximately completed. S2 is an example of the second step.

[0051] In step S2, the laser light L1 causes a change in the coating 21, thereby forming a space S as shown in FIG. 5 at the interface between the coating 21 and the coating 22, and the coating 21 and the coating 22 are separated via the space S.

[0052] In this embodiment, as described above, the absorption coefficient (absorption rate) of the coating 22 for the laser light L1 is higher than the absorption coefficient (absorption rate) of the coating 21 for the laser light L1. Therefore, when irradiated with the laser light L1, the coating 21 can absorb more energy than the coating 22. As a result, it can be assumed that the coating 21 melts, vaporizes, and foams, creating a space S between the coating 21 and the coating 22, causing the coatings 21 and 22 to separate. For this reason, the power density of the laser light L1 is set to be equal to or higher than the power density at which the coating 21 melts or vaporizes. This allows the coatings 21 and 22 to be more reliably separated (peeled off). Furthermore, the power density of the laser light L1 is set to be lower than the power density at which the coating 21 is carbonized. This prevents carbides produced by the carbonization of the coating 21 from remaining on the surface 11a of the conductor 11, i.e., prevents charring. The specific numerical range of the power density can be determined based on the results of experiments and simulations according to the specifications of the materials, thicknesses, etc. of the coatings 21 and 22 and the conductor 11 .

[0053] In the scanning of S2 with the laser light L1, for example, in the area Ar, scanning of the laser light L1 in the X direction and scanning in the direction opposite to the X direction are performed while being shifted little by little in the Y direction at predetermined intervals in the Y direction, thereby making it possible to reduce the variation in the energy density of the laser light L1 depending on the location.

[0054] [Separation of the Peeled Portion and the Remaining Portion of the Second Coating] After S2, as shown in FIGS. 6 and 7 , the optical head 120 irradiates the laser beam L2 onto the edge of the region Ar while scanning, i.e., the boundary B between the peeled portion 22b of the coating 22 that is separated from the coating 21 and the non-peeled portion 22c of the coating 22 that is not separated from the coating 21. In this case, the boundary B is the peripheral portion of the peeled portion 22b, i.e., the peripheral portion of the range where the laser beam L1 is irradiated in S2 and the space S is formed. As a result, a gap g is formed at the boundary B, as shown in FIG. 7 , separating the peeled portion 22b from the non-peeled portion 22c (S3). FIG. 6 shows the initial state of S3, and FIG. 7 shows the state after S3 is substantially completed. S3 is an example of the third step. 8, the position (cutting line) at which the gap g is formed and cut is not limited to the above-described boundary B, but may be located inside the boundary B, i.e., on the opposite side of the non-peeled portion 22c from the boundary B. In this case, a part of the peeled portion 22b may remain attached to the non-peeled portion 22c.

[0055] The scanning of the laser light L2 at S3 is performed along the direction in which the boundary B extends. For example, at a boundary B extending in the Y direction, scanning of the laser light L2 in the Y direction and scanning in the direction opposite to the Y direction are performed repeatedly. Furthermore, although not shown, at a boundary B extending in the X direction, scanning of the laser light L2 in the X direction and scanning in the direction opposite to the X direction may be performed repeatedly. At a boundary B extending in another direction, scanning is also performed along the direction in which the boundary B extends.

[0056] [Order of Steps 2 and 3] In this embodiment, as described above, step S3 is performed after step S2. However, this is not limited thereto, and step S3 may be performed before step S2. That is, the coating 22 may be pre-cut by scanning and irradiating the laser beam L2 to form a gap g as shown in FIG. 7 (S3). In this case, at the end of step S3, both the peeled portion 22b (the portion to be peeled) and the non-peeled portion 22c (the portion not to be peeled) are attached to the coating 21. Thereafter, a space S as shown in FIG. 5 may be formed, thereby separating the region inside the cutting line from the coating 21 (S2). Note that step S3 may be performed by a method other than laser beam cutting, such as cutting using a cutting tool such as a cutter.

[0057] 9 to 12 are plan views showing the scanning pattern of the laser light L1 at S2, the area Ar, the boundary B, and the cutting line C. FIGS. 9 and 10 show examples in which the scanning paths (scanning trajectories) do not intersect, while FIGS. 14 and 15 show examples in which the scanning paths intersect. The scanning path may have linear sections as in FIGS. 9 to 11, or may have curved sections as in FIG. 12. The scanning procedure is not limited to the one described above; the scanning direction may be different from the procedure described above, and the laser light L1 may scan the entire area Ar multiple times.

[0058] [Removal of peeled portion] After S3, as shown in Fig. 13, the peeled portion 22b is removed (S4). In S4, the peeled portion 22b may be blown away by gas G, or may be mechanically removed by applying force to the peeled portion 22b using a tool or the like. Furthermore, if the peeled portion 22b automatically falls off due to thermal deformation or the like of the peeled portion 22b, S4 is not necessary. S4 may also be referred to as a fifth step.

[0059] [Removal of First Coating] After the peeled portion 22b is removed, as shown in Figures 14 and 15, the laser beam L3 from the optical head 120 is scanned and irradiated onto the area Ar of the electric wire 10 to be removed, thereby burning and removing the coating 21 in the area Ar (S5). Figure 14 shows the initial state of S5, and Figure 15 shows the state after step S5 is substantially completed. If pulsed laser beams were irradiated as the laser beam L3 in S5, the pulsed laser beams would have a high power density, which could cause irregularities on the surface 11a of the conductor 11. In this regard, in the present embodiment, continuous wave laser beams L3, which have a lower power density than pulsed laser beams, are irradiated as the laser beam L3, which makes it easier to reduce irregularities on the surface 11a, thereby obtaining a higher quality surface 11a.

[0060] Furthermore, according to this embodiment, the continuous-wave laser beams L, L1 to L3 can burn predetermined portions of the coatings 21, 22 made of synthetic resin material without carbonizing them. In particular, if the coating 21 is carbonized in S5, residue of the carbonized coating 21 may adhere to the surface 11a of the conductor 11, making it difficult to remove, and there is a risk that the surface 11a may have to be thinly scraped off. In this regard, in this embodiment, the continuous-wave laser beams L, L1 to L3 are irradiated at a power density lower than that of pulsed laser beams, thereby burning the coatings 21, 22 without carbonizing them as much as possible, thereby making it easier to avoid undesirable situations in which the coatings 21, 22 are difficult to remove.

[0061] As described above, in this embodiment, the laser beam L1 is irradiated onto the electric wire 10 (the object to be processed) while being scanned. The laser beam L1 passes through the coating 22 (second coating), causing a change in the coating 21 (first coating), thereby separating the coating 21 from the coating 22. This method allows the total amount of energy imparted to the coatings 21 and 22 by the laser beam L1 to be kept lower than when removing the coating 22 by burning or carbonizing it. This results in, for example, more efficient and faster removal of the coatings 21 and 22. Furthermore, the formation of a space S between the coatings 21 and 22 and the connection of the space S with the outside via the cutting line C or the like allow oxygen to be introduced into the space S. Furthermore, the removal of the coating 22 exposes the coating 21. This allows a sufficient supply of oxygen when the coating 21 is burned by irradiation with the laser beam L2, thereby more reliably burning the coating 21. In other words, according to this embodiment, it is easier to suppress the remaining carbide (burning) due to incomplete combustion of the coating 21, compared to when both coatings 21 and 22 are removed at once by irradiating them with laser light.

[0062] While the above describes exemplary embodiments and modifications of the present invention, these are merely examples and are not intended to limit the scope of the invention. The above embodiments and modifications can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, and the like (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be appropriately modified and implemented.

[0063] For example, the present invention may include a configuration in which a first coating is directly covered with a second coating having a lower laser light absorption rate than the first coating, and the coating may include a coating other than the first and second coatings, or the first coating may indirectly cover the surface of the base material via another coating. Furthermore, the object to be processed is not limited to a configuration in which the entire periphery of the base material is covered with a coating, and is not limited to an electric wire.

[0064] The present invention can be used in a coating removal method and a coating removal device.

[0065] DESCRIPTION OF SYMBOLS 10... Electric wire (object to be processed) 10a... Surface 11... Conductor (base material) 11a... Surface 21... Coating (first coating) 21a... Surface 22... Coating (second coating) 22a... Surface 22b... Peeled portion 22c... Non-peeled portion 100... Laser processing device (coating removal device) 110... Laser device 110a... Housing 110b... Laser module 110c... Lens 120... Optical head 121... Collimating lens 122... Condenser lens 124... Mirror 126... Laser scanner 130... Optical fiber 140... Control device 150... Driving mechanism 160... Gas supply mechanism 161... Piping 161a... Discharge port Ar... Area B... Boundary C... Cutting line G... Gas g... Gap L, L1 to L3... Laser light P... Irradiation point S... Space S1 to S5...Process X...direction Y...direction Z...direction

Claims

1. A coating removal method comprising: a first step of arranging an object to be processed, the object having a base material made of a metal material, a first coating made of a synthetic resin material and covering the surface of the base material directly or indirectly via another coating, and a second coating made of a synthetic resin material covering the first coating on the opposite side of the surface of the base material and having a lower laser light absorption rate than the synthetic resin material constituting the first coating, and an optical head in a predetermined positional relationship so that the laser light output from the optical head is irradiated onto the surface of the object to be processed; and a second step of, after the first step, irradiating the laser light from the optical head onto the object to be processed while scanning it, and separating the first coating from the second coating by causing a change in the first coating with the laser light that has passed through the second coating.

2. A coating removal method according to claim 1, wherein in the second step, a space is formed between the first coating and the second coating by irradiating the laser light that has passed through the second coating.

3. A coating removal method according to claim 2, wherein in the second step, the first coating is foamed by irradiation with the laser light that has passed through the second coating.

4. A coating removal method according to any one of claims 1 to 3, wherein in the second step, the power density of the laser light is less than the power density at which the first coating is carbonized and equal to or greater than the power density at which the first coating is melted or vaporized.

5. A coating removal method according to claim 1, wherein the wavelength of the laser light is 400 nm or more and 550 nm or less.

6. The coating removal method according to claim 1, wherein the laser light includes blue laser light.

7. The coating removal method according to claim 1, wherein in the second step, the laser light is a continuous wave laser light.

8. A coating removal method according to claim 1, further comprising a third step of cutting the second coating to separate the second coating into a portion that is separated from the first coating and a portion that is not separated from the first coating.

9. A coating removal method according to claim 8, wherein in the second step, a space is formed between the first coating and the second coating by irradiating the laser light that has passed through the second coating, and in the third step, the second coating is cut at a position that is a boundary between a region where the space is formed and the second coating has peeled off from the first coating, and a region where the second coating has not peeled off from the first coating.

10. The coating removal method according to claim 8, wherein in the third step, the cutting is carried out by irradiating with laser light.

11. The coating removal method according to claim 8, wherein the third step is carried out after the second step.

12. The coating removal method according to claim 8, wherein the third step is carried out before the second step.

13. A film removal method according to claim 1, further comprising a fourth step of removing the first film remaining in the second step by irradiating the laser light from the optical head.

14. A coating removal device comprising: a laser device that outputs laser light; and an optical head that irradiates the laser light output from the laser device while scanning it onto the surface of an object to be processed, wherein the object to be processed has a base material made of a metal material, a first coating made of a synthetic resin material that covers the surface of the base material directly or indirectly via another coating, and a second coating that covers the side of the first coating opposite the surface and is made of a synthetic resin material that has a lower absorption rate for the laser light than the synthetic resin material that constitutes the first coating, and wherein the laser light that has passed through the second coating causes a change in the first coating, thereby separating the first coating from the second coating.

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