Coating removal method and coating removal device

Abstract

For example, a new and improved coating removal method and coating removal device is provided. [Solution] A coating removal method for removing a coating from an electric wire having a core wire and an insulating coating made of an organic polymer material includes the steps of: placing the electric wire in a position where a laser beam can be irradiated onto the surface of the electric wire; and removing the coating by irradiating each location on the surface of the electric wire with a laser beam having a wavelength of 300 nm or more and 500 nm or less multiple times. The removal step may include a first step of burning and thinning the coating with energy imparted to the coating by the laser beam; and a second step of burning and removing the coating thinned in the first step with energy imparted to the core wire and the coating by the laser beam.

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, a coating removal method and a coating removal device are known that remove a coating from an electric wire by irradiating the wire with laser light to expose a conductor covered by the coating (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-220634 Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of film removal method, it would be beneficial to have an improved new film removal method that can achieve a higher level of both suppression of film residue and reduction of the impact on the conductor.

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

[0006] The coating removal method of the present invention is a method for removing a coating from, for example, an electric wire having a core wire and an insulating coating made of an organic polymer material, and includes the steps of: placing the electric wire in a position where a laser beam can be irradiated onto the surface of the electric wire; and removing the coating by irradiating each location on the surface of the electric wire in a target area where the coating is to be removed with the laser beam having a wavelength of 300 nm or more and 600 nm or less multiple times.

[0007] In the coating removal method, the removal step may include a first step of irradiating the laser light onto the surface of the electric wire to thin the coating, and a second step of irradiating the laser light onto the coating thinned in the first step to remove the coating.

[0008] In the coating removal method, in the first step, the thickness of the coating may be set to 1 μm or less.

[0009] In the coating removal method, the energy amount of the laser light output in the first step may be equal to or greater than the energy amount of the laser light output in the second step.

[0010] In the coating removal method, the power density at the focal position of the laser light in the second step may be greater than the power density at the focal position of the laser light in the first step.

[0011] In the coating removal method, the first step and the second step may differ in at least one of the following: power density at the focal position of the laser light, power of the laser light, spot diameter of the laser light on the surface, scanning speed when scanning the spot of the laser light on the surface, and amount of shift when scanning the spot of the laser light on the surface multiple times while shifting it in a direction intersecting the scanning direction.

[0012] In the coating removal method, in the first step, the coating may be burned by energy imparted to the coating from the laser light, and in the second step, the coating may be burned by energy imparted to the core wire and the coating from the laser light.

[0013] In the film removal method, the removing step may include a step of irradiating a specific region of the region from which the film is to be removed with the laser light beam while scanning the specific region multiple times.

[0014] In the coating removal method, in the step of irradiating the specific region with the laser light beam while scanning it multiple times, the scanning position may be shifted in a direction intersecting the scanning direction.

[0015] In the coating removal method, the amount of deviation of the scanning position may be equal to or greater than 1 / 3 and equal to or less than 1 / 2 of the width of the irradiation area during scanning.

[0016] In the coating removal method, the laser light may be scanned multiple times with a shift in a direction intersecting the scanning direction, so that the irradiation areas of two consecutive scans partially overlap in the direction intersecting the scanning direction.

[0017] In the coating removal method, an overlap rate of widths of irradiation regions between two successive scans may be 1 / 4 or more.

[0018] In the coating removal method, an overlap rate of widths of irradiation regions between two successive scans may be 5 / 6 or less.

[0019] In the coating removal method, an overlap rate of widths of irradiation regions between two successive scans may be equal to or greater than 1 / 4 and equal to or less than 5 / 6.

[0020] In the film removal method, the removing step is performed by setting the power density of the laser light at the focal position to 230 [kW / cm 2 In the above state, the method may include a step of irradiating the electric wire with a laser beam spot while scanning the electric wire.

[0021] In the film removal method, the removal step includes a step of irradiating a specific region of the region to be removed with the laser light beam while scanning the region, multiple times, and in the final step of the multiple steps, the power density at the focal position of the laser light is 230 [kW / cm 2 In this state, the electric wire may be irradiated with a laser beam spot while being scanned.

[0022] In the coating removal method, the wavelength of the laser light may be not less than 400 [nm] and not more than 550 [nm].

[0023] In the film removal method, in the removal step, the power density at the focal position of the laser light is 350 [kW / cm 2 ] or more.

[0024] In the film removal method, in the removing step, the diameter of the beam at the focal position of the laser light may be 500 μm or less.

[0025] In the film removal method, in the removing step, the diameter of the laser beam at the focal position may be 200 μm or more.

[0026] In the coating removal method, the diameter of the laser beam at the focal position may be 300 μm or more and 400 μm or less.

[0027] In the coating removal method, the laser light may be a continuous wave laser.

[0028] In the coating removal method, the laser light may be laser light output from one laser module, and the power of the one laser module may be 400 W or more.

[0029] In the film removal method, the power of the one laser module may be 1 kW or less.

[0030] In the coating removal method, the laser beam spot may be scanned using a laser scanner.

[0031] In the coating removal method, the electric wire may be rotated about a central axis extending in an axial direction of the electric wire to scan the spot of the laser light.

[0032] In the coating removal method, the spot of the laser light may be scanned using a laser scanner, and the spot of the laser light may be scanned by rotating the electric wire about a central axis extending in the axial direction of the electric wire.

[0033] In the coating removal method, the ends of two electric wires, each of which is the electric wire, may be butted together to arrange the two electric wires in a substantially straight line, and the coating may be removed at a portion adjacent to the ends of the two electric wires.

[0034] In the coating removal method, the coating may be removed from a longitudinally intermediate portion of the electric wire, and the electric wire may be cut in two in the longitudinal direction at a longitudinally intermediate position of the section from which the coating has been removed.

[0035] In the coating removal method, the laser light may be output from an optical head, the central axis of the electric wire may be positioned at a position away from the optical head in a first direction, and the coating to be removed may be positioned within a range of ±3 mm or less in the first direction from the focal position of the laser light.

[0036] In the coating removal method, the laser light is output from an optical head, the electric wire has a plurality of side surfaces extending in the longitudinal direction and a plurality of ridge lines as corners extending in the longitudinal direction between two adjacent side surfaces, and the laser light is irradiated onto the coating with one of the plurality of ridge lines and two side surfaces on both sides of the ridge line facing the optical head, and the coating constituting the one ridge line, the two side surfaces, and the ridge lines adjacent to each of the two side surfaces on the opposite side of the one ridge line may be targeted for removal.

[0037] In the coating removal method, the central axis of the electric wire is positioned at a distance in a first direction from the optical head, and the two side surfaces are each positioned in a position where a plane perpendicular to the first direction is rotated a predetermined angle around the central axis, and the two side surfaces are positioned in positions where the minimum angular difference between their normal directions and the direction opposite to the first direction is different from each other, and the larger the minimum angular difference, the higher the power density in a virtual plane perpendicular to the first direction of the laser light irradiated to the side surface.

[0038] In the coating removal method, the central axis of the electric wire may be positioned at a position away from the optical head in a first direction, and the power density in an imaginary plane perpendicular to the first direction of the laser light irradiated onto an adjacent ridge line on the opposite side of the side surface from the one ridge line may be made higher than the power density in the imaginary plane of the laser light irradiated onto the one ridge line and the two side surfaces.

[0039] In the coating removal method, the end of the electric wire may have a convex shape that protrudes in a longitudinal direction of the electric wire.

[0040] In the film removal method, the removing step may involve removing the film while supplying oxygen.

[0041] In the coating removal method, the laser light may include laser light of a wavelength at which the absorption rate of the coating is 80% or more.

[0042] In the film removal method, in the removing step, the removed region of the film may expand in a second direction, and oxygen may be supplied in a direction including a component in the second direction.

[0043] In the coating removal method, the scanning direction of the beam may be changed over time in the removing step.

[0044] In the coating removal method, in the removal step, the beam may move in a reversing or spiral manner on the surface so that the removal area of ​​the coating gradually expands in at least a portion of the scanning of the beam.

[0045] In the coating removal method, the irradiation power of the laser light per unit area of ​​the surface may be changed during the process of scanning the beam to remove the coating.

[0046] In the film removal method, in the removing step, the irradiation power of the laser light per unit area of ​​the surface may be reduced during the process of scanning the beam to remove the film.

[0047] In the coating removal method, in the removal step, the irradiation power of the laser light per unit area of ​​the surface may be changed by changing at least one of the scanning speed of the laser light and the output of the light source of the laser light.

[0048] In the coating removal method, in the removing step, the electric wire and the beam may move relatively in an axial direction of the electric wire in at least a portion of a scanning section of the beam.

[0049] In the coating removal method, in the removing step, the electric wire and the beam may move relatively in a direction intersecting an axial direction of the electric wire in at least a portion of a scanning section of the beam.

[0050] In the coating removal method, the core wire may be made of a copper-based metal material.

[0051] In the coating removal method, the electric wire may be a rectangular wire or a round wire.

[0052] In the film removal method, in the removing step, the film may remain in a round before the final round of irradiation at each location among the multiple rounds of irradiation.

[0053] In the coating removal method, in the removing step, an area of ​​the coating that is not to be removed may be covered with a cover.

[0054] The coating removal device 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 toward the surface of an electric wire having a core wire and a coating made of an organic polymer material, and removes the coating by irradiating the laser light multiple times to each location on the surface in the area where the coating is to be removed.

[0055] In the coating removal device, the wavelength of the laser light is 300 [nm] or more and 600 [nm] or less, and the power density at the focal position of the laser light is 2.3 [kW / mm 2 ] or more.

[0056] In the film removal device, the laser light may be output from one laser module included in the laser device, and the power of the one laser module may be 150 W or more.

[0057] The film removal device may include an optical fiber that propagates the laser light output from the laser module to the optical head, and the core diameter of the optical fiber may be 200 μm or less.

[0058] In the coating removal device, the laser device may combine and output a plurality of laser beams having different wavelengths in the range of 300 nm to 600 nm. [Effects of the Invention]

[0059] According to the present invention, for example, a novel and improved coating removal method and coating removal device can be provided. [Brief explanation of the drawings]

[0060] [Figure 1]FIG. 1 is an exemplary schematic perspective view of a portion of an electric wire from which a coating is removed by a coating removal method according to an embodiment. [Figure 2] FIG. 2 is an exemplary schematic configuration diagram of the film removal device according to the first embodiment. [Figure 3] FIG. 3 is a graph showing the light absorptance by a metal material versus the wavelength of light when light is irradiated onto an organic polymer material. [Figure 4] FIG. 4 is a graph showing the light absorptance of an organic polymer material relative to the wavelength of light when the organic polymer material is irradiated with light. [Figure 5] FIG. 5 is an exemplary schematic graph showing a comparison of the power density distribution (solid line) at the focal position of the laser beam in the coating removal method of the embodiment with the power density distribution (dashed line) at the focal position of the conventional laser beam. [Figure 6] FIG. 6 is a photographic image of the surface of a portion of the electric wire that was treated by the coating removal method of the reference example. [Figure 7] FIG. 7 is a photographic image of a cross section near the surface of the part in FIG. [Figure 8] FIG. 8 is a photographic image of the surface of a portion of an electric wire that has been treated by the coating removal method of the embodiment. [Figure 9] FIG. 9 is a photographic image of a cross section near the surface of the part in FIG. [Figure 10] FIG. 10 is a photographic image of the surface of a portion of the electric wire that has been treated under conditions different from those shown in FIGS. 8 and 9 by the coating removal method according to the embodiment. [Figure 11] FIG. 11 is a photographic image of a cross section near the surface of the part in FIG. [Figure 12] FIG. 12 is an exemplary schematic plan view showing the procedure of the film removal method according to the first embodiment and the change over time of the electric wire. [Figure 13] FIG. 13 is an exemplary explanatory diagram showing adjacent scanning paths and overlapping rates in the coating removal method according to the first embodiment. [Figure 14]FIG. 14 is an exemplary schematic side view of a portion of an electric wire from which at least a part of the coating is removed by the coating removal method of the first embodiment. [Figure 15] FIG. 15 is a schematic diagram showing the direction of oxygen supplied by the film removal method of the first embodiment. [Figure 16] FIG. 16 is an exemplary schematic side view of a portion of an electric wire from which a coating is removed by the coating removal method of the first embodiment, showing a case where the oxygen supply position is different from that in FIG. [Figure 17] FIG. 17 is an illustrative schematic plan view showing another example of the scanning path of the laser light beam in the coating removal method of the first embodiment. [Figure 18] FIG. 18 is an exemplary schematic plan view showing the procedure of the film removal method according to the second embodiment and the change over time of the electric wire. [Figure 19] FIG. 19 is an exemplary schematic side view showing the change over time of an electric wire in the film removal method of the second embodiment. [Figure 20] FIG. 20 is an illustrative diagram showing a scanning path when the overlap ratio is 1 / 2 in the coating removal method according to the second embodiment. [Figure 21] FIG. 21 is an illustrative diagram showing a scanning path when the overlap rate is 1 / 3 in the coating removal method according to the second embodiment. [Figure 22] FIG. 22 is an exemplary schematic front view of an electric wire viewed in the axial direction when a coating is removed by scanning a laser beam on two side surfaces of the electric wire in the coating removal method of the third embodiment. [Figure 23] FIG. 23 is an exemplary schematic front view of an electric wire viewed in the axial direction when a coating is removed by scanning a laser beam on two side surfaces of the electric wire different from those shown in FIG. 6 in the coating removal method of the third embodiment. [Figure 24] FIG. 24 is an exemplary schematic perspective view of a portion of the coating removal device of the fourth embodiment. [Figure 25] FIG. 25 is an exemplary schematic side view showing a procedure for removing a coating by the coating removal method of the fifth embodiment. [Figure 26]FIG. 26 is an exemplary schematic side view showing a procedure for removing a coating by the coating removal method of the sixth embodiment. [Figure 27] FIG. 27 is an exemplary schematic side view of a portion of the coating removal device of the sixth embodiment. [Figure 28] FIG. 28 is an exemplary schematic front view, seen in the axial direction, of an example of an electric wire as a target for removing a coating by the coating removal method of the embodiment. [Figure 29] FIG. 29 is an exemplary schematic front view, seen in the axial direction, of an example of an electric wire as a target for removing a coating by the coating removal method of the embodiment. [Figure 30] FIG. 30 is an illustrative schematic front view, seen in the axial direction, of an example of an electric wire as a target for removing a coating by the coating removal method of the embodiment. [Figure 31] FIG. 31 is an exemplary schematic front view, seen in the axial direction, of an example of an electric wire as a target for removing a coating by the coating removal method of the embodiment. [Figure 32] FIG. 32 is an exemplary schematic side view of an end portion of an example of an electric wire as a target for removing a coating by the coating removal method of the embodiment. [Figure 33] FIG. 33 is an illustrative schematic side view of an end portion of an example of an electric wire as a target for removing a coating by the coating removal method of the embodiment. [Figure 34] FIG. 34 is an exemplary schematic perspective view of an end portion of an example of an electric wire as a target for removing a coating by the coating removal method of the embodiment. [Figure 35] FIG. 35 is an exemplary schematic plan view of a portion of a coating removal device according to a modified example of the embodiment. [Figure 36] FIG. 36 is an exemplary schematic front view of a portion of the modified coating removal device of FIG. [Figure 37] FIG. 37 is an exemplary schematic plan view of a portion of a coating removal device according to another modified example different from those shown in FIGS. [Figure 38] FIG. 38 is an exemplary schematic side view of a portion of a coating removal device according to another modified example different from those shown in FIGS. DETAILED DESCRIPTION OF THE INVENTION

[0061] 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.

[0062] The following embodiments have similar configurations. Therefore, according to the configurations of each embodiment, similar actions and effects based on the similar configurations can be obtained. Furthermore, in the following, similar configurations are given similar reference numerals, and duplicated descriptions may be omitted.

[0063] 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.

[0064] [First embodiment] [Electric wire] FIG. 1 is a perspective view of an electric wire 10 from which an insulating coating 12 is removed by a coating removal method of a first embodiment. As shown in FIG. 1, the electric wire 10 is, for example, a rectangular wire having a flattened rectangular cross section. The electric wire 10 has a conductor 11 having a strip-like and plate-like shape and an insulating coating 12 surrounding the conductor 11. In the example of FIG. 1, the X direction can be referred to as the axial direction or longitudinal direction, the Y direction can be referred to as the lateral direction or width direction, and the Z direction can be referred to as the thickness direction. The conductor 11 is an example of a core wire.

[0065] The conductor 11 is made of a copper-based metal material such as oxygen-free copper or a copper alloy. The insulating coating 12 is made of an organic polymer material such as polyimide, polyether ether ketone, polyamide-imide, polyurethane, polyester, or polyester-imide. The organic polymer material may also be called a synthetic resin material. The thickness of the insulating coating 12 may be set to various values, and the insulating coating 12 may be a laminate of multiple layers.

[0066] 1, in order to electrically connect the conductor 11 to another conductor, the insulating coating 12 is removed, for example, in a predetermined range A from the end of the conductor 11. That is, the predetermined range A is a region that is a target for removing the insulating coating 12. Note that the position from which the insulating coating 12 is removed is not limited to the end of the electric wire 10, and may be, for example, a midpoint in the longitudinal direction of the electric wire 10. The predetermined range A may also be referred to as a target region.

[0067] The insulating coating 12 is removed by irradiating the surface 10a (side surface) of the electric wire 10, which is set at a position where the laser light is to be irradiated. When removing the insulating coating 12, for example, as indicated by the dashed arrow in FIG. 1, a point-like spot (beam) of laser light is scanned on the surface 10a, i.e., on the insulating coating 12. At the position where the spot is irradiated, the insulating coating 12 is at least partially burned and removed. The scanning direction of the spot may change over time. In this embodiment, the spot moves repeatedly while being folded back on the surface 10a. The spot and the electric wire 10 move relatively in a direction (Y direction and the opposite direction Yo to the Y direction) intersecting the axial direction (X direction) of the electric wire 10. In the example of FIG. 1, scanning of the spot includes scanning in a scanning direction SD1 (Y direction) and scanning in a scanning direction SD2 (the opposite direction Yo to the Y direction). In the example of FIG. 1 , the spot scans from the surface 10a of the electric wire 10 to a position off the surface 10a and then turns back in the Y direction at the position off the surface 10a. In this case, the output of the laser light may be reduced or stopped at the position off the surface 10a. However, this is not limited thereto. Between scanning in the scanning direction SD1 and scanning in the scanning direction SD2, the spot and the electric wire 10 may move on the surface 10a in the axial direction of the electric wire 10, thereby scanning the spot on the surface 10a in the axial direction. As the spot moves back and forth in this manner, the removed region of the insulating coating 12 gradually expands. In this embodiment, the removed region expands macroscopically in the removal direction RD over time, and microscopically in the scanning directions SD1 and SD2 as the spot (beam) scans.

[0068] The scanning range, return position, scanning direction, number of scans, etc. are not limited to those shown in FIG. 1. For example, the removal area may be expanded in the opposite direction of the X direction, or the removal area may be expanded in the Y direction or the opposite direction of the Y direction by repeating scanning in the X direction and the opposite direction of the X direction. Furthermore, the scanning trajectory is not limited to a return trajectory, but may be a spiral trajectory. In this case, too, the removal area of ​​the insulating coating 12 gradually expands as the spot moves in a spiral pattern. Furthermore, surfaces of the insulating coating 12 other than those shown in FIG. 1 can also be removed in a similar manner.

[0069] [Laser processing equipment] Fig. 2 is a schematic configuration diagram of the laser processing apparatus 100A (100). As shown in Fig. 2, the laser processing apparatus 100 includes 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.

[0070] 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.

[0071] The laser module 110b outputs laser light having a wavelength of 300 nm or more and 600 nm or less. It outputs continuous wave laser light. In other words, the laser light is a continuous wave laser. The laser module 110b is, for example, a chip-on-submount. The laser module 110b may also be called a laser oscillator. The laser light may be a pulsed laser.

[0072] 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.

[0073] The optical fiber 130 guides the laser light output from the laser device 110 to the optical head 120 .

[0074] 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.

[0075] 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 laser light on the surface 10a of the electric wire 10. 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.

[0076] The collimating lens 121 collimates the laser light input via the optical fiber 130. The collimated laser light becomes parallel light.

[0077] Mirror 124 reflects the laser light that has been collimated by collimator lens 121. In the example of Fig. 2, 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.

[0078] 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 (none of which are shown) controlled by the control device 140. The laser scanner 126 is an example of a scanning mechanism that scans a beam (spot) of the laser light L on the surface 10a of the electric wire 10. Note that the optical head 120 may have a laser scanner 126 other than a galvanometer scanner.

[0079] The condensing lens 122 condenses the laser light as parallel light and irradiates it as laser light L (output light) onto 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, towards the electric wire 10 in a direction substantially along the opposite direction to the Z direction.

[0080] The laser processing apparatus 100 also includes a drive mechanism 150 and an oxygen supply mechanism 160 .

[0081] The driving mechanism 150 changes the relative position of the optical head 120 with respect to the electric wire 10. The driving mechanism 150 includes, 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.

[0082] The oxygen supply mechanism 160 supplies oxygen gas Go (gas containing oxygen) toward the irradiation point P through a pipe 161. The oxygen gas Go is discharged at a predetermined flow rate from an outlet 161a of a nozzle provided at the tip of the pipe 161 and facing the irradiation point P. The laser processing apparatus 100 removes the insulating coating 12 from the electric wire 10 by irradiating the electric wire 10 with laser light L while supplying the oxygen gas Go. The supply of the oxygen gas Go promotes combustion of the insulating coating 12, and the removal performance of the insulating coating 12 can be improved compared to when the oxygen gas Go is not supplied.

[0083] Through intensive research by the inventors, it has been found that the distance D between the discharge port 161a and the irradiation point P is preferably 5 mm or more and 25 mm or less, and more preferably 10 mm or more and 20 mm or less. It has also been found that the flow velocity of the oxygen gas Go at the discharge port 161a is preferably 3.0 m / s or more and 35 m / s or less. Furthermore, it has been found that the inner diameter of the discharge port 161a (nozzle) is preferably equal to or greater than the width of the electric wire 10 so that the amount of oxygen supplied is less likely to vary across the entire width of the electric wire 10. For example, when the inner diameter is 8 mm, the flow rate of the oxygen gas Go required to obtain the above-mentioned flow velocity of 3.0 m / s or more and 35 m / s or less is 10 L / min or more and 100 L / min or less. It was also found that in various cases, the flow rate of the oxygen gas Go is preferably 30 [L / min] or more, more preferably 50 [L / min] or more, and even more preferably 70 [L / min] or more. If the distance D is too short, the thermal effect on the nozzle increases, while if it is too long, it becomes difficult for the oxygen gas Go to be supplied to the irradiation point P. It was also found that within the range of the distance D, if the flow rate of the oxygen gas Go is less than 50 [L / min], the removal performance of the insulating coating 12 decreases.

[0084] The inventors have confirmed that by setting the distance D and the oxygen gas Go in this way, the laser processing device 100 can quickly remove the insulating coating 12 from an electric wire 10 having a thickness of 30 μm or more, 50 μm or more, or even 70 μm or more, thereby obtaining a high-quality surface of the conductor 11 with little residue, etc.

[0085] 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 oxygen supply mechanism 160. The control device 140 is, for example, a computer having a controller, a main memory unit, an auxiliary memory unit, etc.

[0086] The control device 140 can control the operation of the laser device 110, for example, to output laser light, stop outputting laser light, or change the output intensity of laser light.

[0087] 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 positions of the optical head 120 and the electric wire 10 change. 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.

[0088] Furthermore, the control device 140 can control the operation of the oxygen supply mechanism 160, for example, to supply oxygen gas Go, stop the supply of oxygen gas Go, or change the supply flow rate of oxygen gas Go.

[0089] The oxygen concentration in the oxygen gas Go is set according to the flammability of the material of the insulating coating 12. Specifically, the higher the flammability of the material of the insulating coating 12, the lower the oxygen concentration is set, and the lower the flammability of the material of the insulating coating 12, the higher the oxygen concentration is set. The oxygen concentration is adjusted, for example, by a switching mechanism such as a solenoid valve that can change the discharge flow rate from the oxygen tank. This configuration and setting can achieve effects such as preventing the insulating coating 12 from burning beyond its intended range and achieving more efficient and rapid combustion. The oxygen concentration in the oxygen gas Go 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. The oxygen concentration is set at a fixed position, for example, at the tip of the nozzle of the piping 161. The oxygen gas may also be air.

[0090] [Laser light wavelength and light absorption rate] FIG. 3 is a graph showing the light absorptance of each metal material versus the wavelength of light when the material is irradiated with light. The horizontal axis of the graph in FIG. 3 represents wavelength, and the vertical axis represents absorptance. FIG. 3 also shows the relationship between wavelength and absorptance for aluminum (Al), copper (Cu), gold (Au), nickel (Ni), silver (Ag), tantalum (Ta), and titanium (Ti). As shown in FIG. 3, the light absorptance of these metal materials varies depending on the wavelength of light, with the shorter the wavelength, the greater the absorptance tends to be.

[0091] FIG. 4 is a graph showing the light absorptance of two types of organic polymer materials (polyether ether ketone: PEEK, polyimide: PI) versus the wavelength of light when the materials are irradiated with light. For PEEK, FIG. 4 shows the absorptance when the coating thickness is 165 μm, and for PI, it shows the absorptance when the coating thickness is 120 μm. The horizontal axis of the graph in FIG. 4 represents wavelength, and the vertical axis represents absorptance. As shown in FIG. 4, the absorptance of these organic polymer materials varies depending on the wavelength of the light, with the absorptance tending to increase as the wavelength becomes shorter.

[0092] The inventors' extensive research has revealed that, from the viewpoint of the absorption rate of laser beam energy by the conductor 11 made of a conductive metal material and the absorption rate of laser beam energy by the insulating coating 12 made of an organic polymer material, the wavelength of the laser beam is preferably, for example, 300 nm to 600 nm, more preferably 400 nm to 550 nm, and even more preferably 500 nm or less. In this case, it has been found that the insulating coating 12 can be efficiently removed by irradiating light with a wavelength that provides an absorption rate of 80% or more for the organic polymer material. This is presumably due to the effect of increasing the flammability of the insulating coating 12 by rapidly increasing the temperatures of the conductor 11 and the insulating coating 12. When removing the insulating coating 12 while taking into consideration the absorption rate according to the material, it is preferable to appropriately set conditions such as the energy amount and power density of the laser light L, taking into consideration, for example, the absorption rate per unit length or unit volume of the insulating coating 12, the thickness of the insulating coating 12, the volume of the insulating coating 12 to be removed, etc.

[0093] [Laser beam diameter and power density] As described above, in this embodiment, the laser device 110 includes only one laser module 110b. If the laser device 110 includes multiple laser modules 110b, it becomes difficult to reduce the focusing area of ​​the laser light output from the laser device 110 due to variations in the specifications of the multiple laser modules 110b and optical components, such as the position and shape, and the laser light including multiple modes. This makes the laser light more likely to diverge than when the laser device 110 includes only one laser module 110b. In other words, when the laser device 110 includes multiple laser modules 110b, the beam diameter of the laser light output from the laser device 110 tends to be larger than the beam diameter of the laser light output from the laser device 110 when the laser device 110 includes only one laser module 110b. Accordingly, the laser light L output from the optical head 120 via the optical fiber 130 also tends to diverge; in other words, the beam diameter of the laser light L also tends to be larger.

[0094] However, when the laser device 110 has only one laser module 110b, it is more difficult to increase the power of the laser light L than when the laser device 110 has only a plurality of laser modules 110b.

[0095] In this regard, in this embodiment, the laser device 110 has only one newly developed laser module 110b that can output laser light having a wavelength of 400 nm or more and 550 nm or less at a high power of 150 W or more. In addition, since the beam diameter of the laser light in the laser device 110 can be reduced, it becomes possible to use the optical fiber 130 having a core diameter of 110 μm or less.

[0096] With this configuration, it is possible for the laser processing device 100 to output laser light L of a suitable wavelength with a smaller beam diameter (spot diameter) and a higher power density to the electric wire 10. The inventors have found that by irradiating the electric wire 10 with laser light L from the laser processing device 100 under predetermined conditions, it is possible to further reduce the residue 12r (see FIG. 7) of the insulating coating 12, significantly shorten the processing time, and further reduce the effects of melting and oxidation on the conductor 11. The suitable conditions will be described below.

[0097] [Optimal irradiation conditions] FIG. 5 compares the power density distribution at each position along a virtual line that passes through the optical axis of the laser light output from the optical head 120 and is perpendicular to the optical axis at the focal position of the laser light between a reference example (dashed line) and this embodiment (solid line). The dashed line in the reference example shows the power density distribution of the laser light output from the optical head when laser light output from multiple laser element modules in a laser device is combined and the combined laser light is output from the laser device via an optical fiber and an optical head. The solid line in this embodiment shows the power density distribution of the laser light L output from one laser module 110b via the optical fiber 130 and the optical head 120. In FIG. 5, the horizontal axis of the graph indicates the position on the virtual line, Ct indicates the position (center) where the virtual line intersects with the optical axis, and the vertical axis of the graph indicates the power density [W / cm 2 ]. Also, d is the beam diameter at the focal position of the laser light L of this embodiment, a is the maximum value of the power density at each position on the imaginary line of the laser light L of this embodiment, dr is the beam diameter at the focal position of the laser light of the reference example, and a is the maximum value of the power density at each position on the imaginary line of the laser light of the reference example. Note that the power density of the beam is 1 / e of the peak power density. 2 The beam diameter can be defined as the diameter within this range. The beam diameter at the focal position is the diameter on a virtual plane Vp (see Figures 12 and 13) that is perpendicular to the opposite direction to the Z direction.

[0098] 5, the maximum value a of the beam power density of the laser light L of this embodiment, which is based on laser light output from one high-output laser module 110b as described above, is greater than the maximum value ar of the power density of the reference example. Furthermore, the beam diameter d of the laser light L of this embodiment is narrower than the beam diameter dr of the laser light of the reference example. Thus, in this embodiment, the laser light output from the laser device 110 having only one high-output laser module 110b is irradiated, so the laser light L can be irradiated in a more concentrated manner over a narrower range than in the case of irradiating laser light output from a laser device having multiple laser modules as in the reference example. This allows the power density of the laser light L to be increased accordingly.

[0099] The wider the beam of laser light L, the more energy is supplied to the surrounding area of ​​the insulating coating 12 to be removed, which reduces energy efficiency and makes it difficult to simultaneously remove the insulating coating 12 by burning it and prevent adverse effects such as melting and oxidation on the conductor 11. In this regard, in the present embodiment, the beam of laser light L can be narrowed to increase the power density, which allows energy to be applied intensively to the area of ​​the insulating coating 12 to be removed, making it possible to burn that area more accurately and reliably, thereby enabling both selective burning of the insulating coating 12 and prevention of adverse effects such as melting and oxidation on the conductor 11 to be simultaneously achieved at a higher level.

[0100] 6, 8, and 10 are photographic images of the surface of a portion of the electric wire that has been treated by the coating removal method, and FIGS. 7, 9, and 11 are photographic images of a cross section near the surface of the treated portion.

[0101] 6 and 7 show the coating removal method of the reference example. Beam diameter at focal position: 600 μm Laser module 110b output: 300 [W] Average power density at the focal point (= power / (cross-sectional area of ​​the beam perpendicular to the optical axis)): 106 [kW / cm 2 ] Scanning speed: 3200 [mm / s] Under these conditions, a discolored area 11d appeared on the surface 11a of the conductor 11, as shown in Fig. 6, and a layer of residue 12r of the insulating coating 12 remained on the surface 11a of the conductor 11, as shown in Fig. 7. It is presumed that the discolored area 11d in Fig. 6 was caused by oxidation of the residue 12r or the conductor 11.

[0102] 8 and 9 show the coating removal method according to the embodiment. Beam diameter at focal position: 400 μm Laser module 110b output: 300 [W] Average power density at the focal point: 239 kW / cm 2 ] Scanning speed: 2000 [mm / s] 8. Under these conditions, as shown in Fig. 8, there is no discolored area 11d on the surface 11a of the conductor 11, unlike in Fig. 6, and the surface 11a is exposed in a clean state. Also, under these conditions, as shown in Fig. 9, the layer of residue 12r is extremely thin compared to the case of Fig. 7, or is nonexistent.

[0103] 10 and 11 show the film removal method according to the embodiment. Beam diameter at focal position: 400 μm Laser module 110b output: 450 [W] Average power density at the focal point: 358 kW / cm 2 ] Scanning speed: 2000 [mm / s] 10, even under these conditions, there is no discolored area 11d on the surface 11a of the conductor 11 as in the case of FIG. 6, and the surface 11a is exposed in an even cleaner state than in FIG. 8. Furthermore, under these conditions, there is almost no layer of residue 12r as shown in FIG. 11.

[0104] Based on an analysis of the experimental results including those described above, the inventors have determined that the following condition (first condition) is satisfied from the viewpoint of achieving both more reliable removal of the insulating coating 12 and prevention of adverse effects on the conductor 11, such as melting and oxidation: The wavelength of the laser light is preferably 400 nm or more and 550 nm or less, and more preferably 500 nm or less. The laser light is preferably a continuous wave laser. The average power density at the focal point of the laser beam L is 230 kW / cm 2 ] or more, and 350 [kW / cm 2 ] or more is preferable. The beam diameter at the focal position is preferably 500 μm or less, and more preferably 400 μm or less. The average power density of the laser light L on the surface 10a of the insulating coating 12 is 250 [kW / cm 2 ] or more, and 350 [kW / cm 2 ] or more is preferable. The power of one laser module 110b included in the laser device 110 is preferably 150 W or more. The core diameter of the optical fiber 130 is preferably 200 μm or less. found.

[0105] Moreover, if the power of the laser light is too high, it becomes difficult to selectively remove the insulating coating 12. From this viewpoint, the inventors have determined that the following condition (second condition): The beam diameter at the focal position is preferably 200 μm or more, and more preferably 300 μm or more. The average power density of the laser light L on the surface 10a of the insulating coating 12 is 650 [kW / cm 2 ] or less, and 550 [kW / cm 2 ] or less is preferable. The power of one laser module 110b included in the laser device 110 is preferably 1 kW or less. found.

[0106] [Procedure for removing the coating] 12 is a plan view showing the procedure for removing the coating in this embodiment. In FIG. 12, the dashed arrow indicates the scanning path of the spot (beam) of the laser light L.

[0107] 12, in this embodiment, the electric wire 10 is first placed at a predetermined position (processing position) relative to the laser processing apparatus 100. Then, a spot (beam) of laser light L is irradiated while scanning over the entire predetermined area A (S11). However, in this case, in S11, the insulating coating 12 is not completely removed, in other words, the conductor 11 is not exposed in the predetermined area A. Therefore, various conditions, such as the size of the spot on the surface 10a, the scanning interval (pitch), the power of the laser device 110, the scanning speed, and the power density per unit area of ​​the laser light on the surface 10a, are set so that the insulating coating 12 is not completely removed, i.e., the conductor 11 is not exposed in the predetermined area A. In this case, the insulating coating 12 is not completely removed in S11, but remains thin, and a step surface 12b that is recessed in the opposite Z direction from the surface 10a appears as the top surface of the remaining portion. In S11, scanning of the spot of laser light L and expansion of the removal area in the removal direction RD may be repeated multiple times until the remaining thickness of the insulating coating 12 becomes a predetermined value (e.g., 1 μm) or less. In this case, the scanning direction and the removal direction RD may be changed as appropriate. S11 is an example of a removal step, and an example of a first step of thinning the insulating coating 12.

[0108] Next, the entire predetermined area A is again irradiated with a spot (beam) of laser light L while scanning (S12). This removes the insulating coating 12 remaining in S11, exposing the conductor 11 (S13). In this case, in S12, various conditions, such as the size of the spot on the surface 10a, the scanning interval, the power of the laser device 110, the scanning speed, and the power density per unit area of ​​the laser light on the surface 10a, are set so that the insulating coating 12 remaining in S11 is removed. Note that in S12, scanning of the spot of laser light L and expansion of the removal area in the removal direction RD may be performed multiple times. In this case, the scanning direction and the removal direction RD may be changed as appropriate. S12 is an example of a removal step and an example of a second step of removing the insulating coating 12 thinned in S11.

[0109] Here, in each of S11 and S12, the spot size and scan interval are set to minimize the variation in power density per unit area, for example, to minimize the occurrence of residue of the insulating coating 12 and unevenness of the exposed conductor 11 within the predetermined range A. FIG. 13 is a plan view showing the irradiation ranges of adjacent scans s1 and s2. In scan s1, a spot S formed by the laser light L is scanned in a scanning direction SD1, and in scan s2, the spot S formed by the laser light L is scanned in a scanning direction SD2. In each of scans s1 and s2, the width W of the irradiation region is the same and is the diameter of the spot S. According to extensive research by the inventors, when the width of the overlapping region between the irradiation regions of adjacent scans s1 and s2 is αW (α: width overlap ratio), it has been found that α is preferably greater than or equal to 1 / 4 and less than or equal to 5 / 6. The spot S is, for example, a spot in an irradiation area when stationary (non-scanning) where the intensity is 1 / e of the peak intensity in the spot S. 2 The diameter of the spot S can be defined as the diameter within this range.

[0110] Furthermore, the power of the laser device 110, the scanning speed, the power density per unit area of ​​the laser beam on the surface 10a, and the like are set in S11 so that the insulating coating 12 remains with each scan. Furthermore, in S12, they are set so that the insulating coating 12 remaining in S11 is removed with one scan, and damage and oxidation of the surface of the conductor 11 are reduced. Note that S11 may be set multiple times. In this case, the above-mentioned conditions may be the same or different for the multiple S11 scans. Furthermore, the above-mentioned conditions may be the same or different for S11 and S12.

[0111] In this embodiment, by steps S11 and S12, each location within the predetermined range A is irradiated with the laser light L multiple times.

[0112] Furthermore, the scanning position may be shifted in a direction intersecting the scanning direction between S11 and S12, or the scanning position may be shifted in a direction intersecting the scanning direction between multiple consecutive S11 scans. Even if such a shift leaves residue of the insulating coating 12 at both ends of the width of the band-shaped irradiation area due to scanning in each S11, the residue can be removed in the next S11 or S12. The inventors' extensive research has revealed that the amount of shift in this case is preferably between 1 / 3 and 1 / 2 of the width W of the irradiation area.

[0113] [Specific examples of the first and second processes] Furthermore, through intensive research by the inventors, it was found that particularly favorable results can be obtained for S11 (first step) and S12 (second step) by setting the removal target and each parameter as shown in Table 1 and performing the removal process of the insulating coating 12 under different conditions for S11 and S12.

[0114] [Table 1]

[0115] First, in step S11, most of the insulating coating 12 is peeled off, and the thickness of the insulating coating 12 remaining at the end of step S11 is at least 1 μm. In this case, the thickness is preferably 0.8 μm or less, and even more preferably 0.5 μm or less. Furthermore, at the end of step S11, the ratio of the area of ​​the exposed conductor 11 to the area of ​​the predetermined range A is preferably 50% or less, more preferably 10% or less, and even more preferably 0%. It has been found that by removing most of the insulating coating 12 in step S11, the total processing time for steps S11 and S12 can be shortened compared to when a thicker insulating coating 12 remains at the end of step S11. Furthermore, it has been found that at the end of steps S11 and S12, a surface 11a with less residual insulating coating 12 and less irregularities can be obtained.

[0116] Furthermore, it has been found that it is preferable to burn the insulating coating 12 with energy imparted to the insulating coating 12 by the laser light L in S11, and to burn the insulating coating 12 with energy imparted to the insulating coating 12 and the conductor 11 by the laser light L in S12. If energy is imparted from the laser light L to the conductor 11 from S11 to S12, excessive energy is likely to occur, which may cause melting or oxidation of the conductor 11 and ultimately result in unevenness on the surface 11a. On the other hand, when the insulating coating 12 is thinned in S12, imparting energy from the laser light L to the conductor 11 as well can more efficiently and quickly heat and burn the remaining insulating coating 12 than imparting energy only to the insulating coating 12. From this perspective, it may be preferable to increase the power density of the laser light L in S12 compared to S11. Furthermore, it is important to impart the energy necessary to burn the insulating coating 12 in S11. When the energy amount of the laser light L output in S11 was equal to or greater than the energy amount of the laser light L output in S12, a surface 11a with little residue of the insulating coating 12 and little irregularities was obtained.

[0117] From this perspective, it has been found that in S11 and S12, the energy amount of the output laser light L (energy amount in Table 1, hereinafter simply referred to as energy amount), the power density at the focal position of the laser light L (power density in Table 1, hereinafter simply referred to as power density), the power of the laser light L (power in Table 1, hereinafter simply referred to as power), the spot diameter of the laser light L on the surface 11a (spot diameter in Table 1, hereinafter simply referred to as spot diameter), the scanning speed of the spot on the surface 11a (scanning speed in Table 1, hereinafter simply referred to as scanning speed), and the deviation amount of the scanning position in S11 and S12 (deviation amount in Table 1, hereinafter simply referred to as deviation amount) are preferably set so as to satisfy the relative relationships shown in Table 1. In particular, in S12, it is preferable to satisfy the first and second conditions described above. Note that, in S11, irradiation under the first and second conditions is not essential, but irradiation under the first and second conditions may be performed.

[0118] Specifically, the power density in S11 is, for example, 150 [kW / cm 2 ] or more and 650 [kW / cm 2 ] or less, and 200 [kW / cm 2 ] or more and 550 [kW / cm 2 It is more preferable that the power density in S12 is, for example, 230 [kW / cm 2 ] or more and 650 [kW / cm 2 ] or less, and 350 [kW / cm 2 ] or more and 550 [kW / cm 2 Furthermore, the power, spot diameter, scanning speed, and displacement are appropriately set so as to satisfy the numerical ranges of the energy amount and power density and the relative relationships between S11 and S12.

[0119] [Oxygen supply] 14 is a side view of a portion of the electric wire 10, illustrating the vicinity of the boundary Bo in the X direction between the removed region Ar and the remaining portion Pr of the insulating coating 12. As described above, the insulating coating 12 is removed by scanning the spot (beam) of the laser light L, thereby forming a step surface 12b and revealing an end face 12a of the insulating coating 12 at the boundary Bo. The end face 12a is located at the end of the insulating coating 12 on the opposite side of the X direction and faces in the opposite direction to the removal direction RD. Note that while FIG. 14 schematically illustrates the end face 12a as extending substantially along the Z direction, in reality, the end face 12a may extend at an angle with respect to the Z direction or may have an uneven shape.

[0120] As shown in Fig. 14, oxygen gas Go is supplied from the side opposite the boundary Bo to the remaining portion Pr and is supplied toward the boundary Bo. If oxygen gas Go were supplied from the side opposite the boundary Bo to the removal region Ar, that is, if oxygen gas were supplied from the right or upper right side of the boundary Bo in Fig. 14, the remaining portion Pr of the insulating coating 12 would obstruct the oxygen gas, and the oxygen gas might not be sufficiently supplied to the vicinity of the boundary Bo, for example, to the corner C between the end face 12a and the step surface 12b. In this regard, in the present embodiment, oxygen gas Go is supplied from the side opposite the boundary Bo to the remaining portion Pr, and therefore can be supplied to the corner C without being obstructed by the remaining portion Pr. This facilitates the combustion of the insulating coating 12 by irradiation with laser light, and reduces the residue on the surface 11a. Furthermore, even when the flow rate of the oxygen gas Go is increased and the residue is blown away by the oxygen gas Go, from the viewpoint of blowing the oxygen gas Go onto the surface 11a up to the corner C while avoiding interference with the remaining portion Pr, it is preferable that the oxygen gas Go be supplied from the side opposite the remaining portion Pr relative to the boundary Bo and be supplied toward the boundary Bo.

[0121] Furthermore, experimental research by the inventors has revealed that the angle θ formed between the supply direction of the oxygen gas Go (the direction of the central axis of the outlet 161a shown in FIG. 2) and the extension direction of the surface 11a (X direction, removal direction RD) is preferably 10° or more and 70° or less, and more preferably 20° or more and 50° or less, from the viewpoint of avoiding interference between the piping 161 in the optical head 120 and the emission end of the laser light, and from the viewpoint of supplying sufficient oxygen to the vicinity of the boundary Bo of the surface 11a.

[0122] 15 is a schematic diagram showing the components of a vector in the supply direction of oxygen gas Go. The supply direction of oxygen gas Go (arrow Go in FIG. 15) can be decomposed into a component Go_rd in the X direction (removal direction RD) and a component Go_z in the opposite direction to the Z direction. That is, oxygen gas Go is supplied in a direction including a component in the opposite direction to the Z direction, i.e., the direction opposite to the normal direction of surface 11a, and a component in the removal direction RD. The removal direction RD is an example of a second direction.

[0123] FIG. 16 is a side view showing the same position as FIG. 14, but illustrates a case where the oxygen gas Go is supplied from a different position than in FIG. 14. In the example of FIG. 16, the oxygen gas Go is supplied toward a position away from the boundary Bo (corner C) in the opposite direction to the removal direction RD (rearward of the removal direction RD). In this example, the oxygen gas Go is supplied from the side opposite the boundary Bo to the remaining portion Pr, and the supply direction of the oxygen gas Go is the same as in FIGS. 14 and 15. In this case, the oxygen gas Go is also supplied to the corner C without being obstructed by the remaining portion Pr, which facilitates the combustion of the insulating coating 12 by irradiation with laser light and reduces the amount of residue. Furthermore, even when the flow rate of the oxygen gas Go is increased and the residue is blown away by the oxygen gas Go, the same effect as in FIG. 14 can be obtained.

[0124] FIG. 17 is a plan view illustrating a scanning path of the spot of laser light L different from that in FIG. 12. In FIG. 17, the dashed arrows indicate the scanning path of the spot (beam) of laser light L. In the example of FIG. 17, the spot is scanned in the X direction and the direction opposite to the X direction. In this case, too, the insulating coating 12 can be removed. Note that the scanning path is not limited to the examples of FIGS. 12 and 17, and can be set in various ways.

[0125] As described above, in this embodiment, by first thinning the insulating coating 12 and then removing it, the intensity of the laser light L can be set lower in both the step (S11) of thinning the insulating coating 12 and the step (S12) of removing the thinned insulating coating 12, compared to when the insulating coating 12 is removed without being thinned. This provides advantages such as suppressing damage and deterioration of the insulating coating 12 outside the predetermined range A due to heat applied from the laser light L and suppressing partial melting of the conductor 11. That is, this embodiment provides advantages such as reducing adverse effects on the surrounding area where the coating is removed and providing a higher-quality exposed surface of the conductor.

[0126] Furthermore, the longer the conductor 11 is exposed to oxygen or air under high heat, the more oxidation may progress. This is particularly true in the present embodiment, where oxygen gas Go is supplied to promote combustion of the insulating coating 12. In this regard, in the present embodiment, the conductor 11 is covered with the insulating coating 12 in step S11, thereby suppressing oxidation of the conductor 11. Furthermore, in step S12, the intensity of the laser light L can be reduced, thereby suppressing heating of the conductor 11 by the laser light L. Furthermore, the thinned insulating coating 12 can be removed in a shorter time than when a thicker insulating coating 12 is removed, thereby further suppressing oxidation of the conductor 11.

[0127] [Second embodiment] FIG. 18 is a plan view showing the procedure for removing a coating in the second embodiment. In FIG. 18, the dashed arrow indicates the scanning path of the spot (beam) of laser light L. As shown in FIG. 18, the scanning path in this embodiment is also the same as in the first embodiment. However, in this embodiment, the region where the insulating coating 12 is removed and the conductor 11 is exposed gradually expands (S21, S22) and is then removed (S23). Note that the scanning path and the direction in which the removed region expands are not limited to those shown in FIG. 18.

[0128] Fig. 19 is a side view showing the change over time of the electric wire 10 when the insulating coating 12 is removed in this embodiment. As shown in Fig. 19, in this embodiment, scan s1 in which the spot of the laser light L moves in the Y direction, scan s2 in which the spot of the laser light L moves in the opposite direction to the Y direction, scan s3 in which the spot of the laser light L moves in the Y direction, and scan s4 in which the spot of the laser light L moves in the opposite direction to the Y direction are performed in this order. The scan path in scan s1, the scan path in scan s2, the scan path in scan s3, and the scan path in scan s4 are aligned in this order in the X direction. Furthermore, among scans s1 to s4, the irradiation areas of the laser light L overlap between two scans adjacent to each other, i.e., scans s1 and s2, scans s2 and s3, and scans s3 and s4. In addition, S24 in FIG. 19 shows scans s1 and s2, S25 shows scans s2 and s3, and S26 shows scans s3 and s4.

[0129] S24 shows the state after scan s1 and scan s2. At the end of scan s2, region A00 of the insulating coating 12 has not been irradiated with the laser light L at all, region A01 has been irradiated with the laser light L only once during scan s1, region A1 has been irradiated with the laser light L twice during scans s1 and s2, and region A2 has been irradiated with the laser light L only once during scan s1. Here, the intensity of the laser light L is set to a height such that approximately half the thickness of the insulating coating 12 is removed with one irradiation and exactly half the insulating coating 12 is removed with two irradiations. Therefore, in S24, the insulating coating 12 is removed in region A1, exposing the conductor 11, approximately half the thickness of the insulating coating 12 is removed in regions A01 and A2, with the other half remaining, and no insulating coating 12 is removed in region A00.

[0130] S25 shows the state after scan s2 and scan s3. At the end of scan s3, region A2 has been irradiated with laser light L twice, in scans s2 and s3, while region A3 has been irradiated with laser light L only once, in scan s3. Therefore, in S25, insulating coating 12 has been removed in region A2, exposing conductor 11, and in region A3, approximately half of the thickness of insulating coating 12 has been removed, leaving the other half.

[0131] S26 shows the state after scan s3 and scan s4. At the end of scan s4, region A3 has been irradiated with laser light L twice, in scans s3 and s4, while region A4 has been irradiated with laser light L only once, in scan s4. Therefore, in S26, insulating coating 12 has been removed in region A3, exposing conductor 11, and in region A4, approximately half of the thickness of insulating coating 12 has been removed, leaving the other half.

[0132] As shown in S24 to S26, in this embodiment, for two consecutive scans in the Y direction, the width of the irradiation area (spot size) and the scanning position are set so that the irradiation areas of the two scans partially overlap in the X direction, and the intensity of the laser light L is set so that just enough insulating coating 12 is removed by the two scans (irradiations), with the scanning positions being shifted slightly in the X direction. Therefore, as shown in Fig. 18, the removed area of ​​insulating coating 12 gradually expands in the X direction.

[0133] Fig. 20 is a plan view showing the irradiation areas of adjacent scans s1 to s3 in this embodiment. In scan s1, the spot S formed by the laser light L is scanned in the scanning direction SD1, in scan s2, the spot S formed by the laser light L is scanned in the scanning direction SD2, and in scan s3, the spot S formed by the laser light L is scanned in the scanning direction SD1. In each of scans s1 to s3, the width W of the irradiation area is the same and is the diameter of the spot S. In the example of Fig. 20, the overlap rate α is set to 1 / 2, and the scan interval is set to 1 / 2W. In this case, the removal area is enlarged as shown in Figs. 18 and 19.

[0134] 21 is a plan view showing the irradiation ranges of adjacent scans s1 to s3 in this embodiment, where the overlap ratio α is set to 2 / 3. In this case, the intensity of the laser light L is set so that the insulating coating 12 is just removed with three scans, and the scan interval is set to 1 / 3 W. In this case, too, the removal area of ​​the insulating coating 12 can be gradually expanded in the X direction.

[0135] In this embodiment, the laser light L is irradiated multiple times to each location within the predetermined range A. Furthermore, the insulating coating 12 is first thinned at each location before being removed. Therefore, the intensity of the laser light L can be set lower than when the insulating coating 12 is removed without being thinned. Therefore, this embodiment also achieves the same effects as the first embodiment.

[0136] In the removal method of this embodiment, the same location is irradiated at least twice to thin the insulating coating 12 before removing it, so the overlap ratio α is set to ½ or more and the scanning interval is set to ½ W or less. This is because if the overlap ratio α is less than ½ and the scanning interval is greater than ½ W, there will be locations where the irradiation is only performed once, which could result in, for example, locations where the insulating coating 12 cannot be removed, locations where residue remains, or unevenness in the conductor 11.

[0137] Furthermore, through extensive research, the inventors have found that it is preferable for the overlap ratio α to be 2 / 3 or less and for the scanning interval to be 1 / 3W or more. This is because if the overlap ratio α is greater than 2 / 3 and the scanning interval is shorter than 1 / 3, it takes time to remove the insulating coating 12, and the conductor 11 is exposed for a longer period of time, making it more susceptible to oxidation. Furthermore, if the overlap ratio α is greater than 1 / 2 and less than 2 / 3, it is possible to prevent a decrease in quality and an increase in the required time.

[0138] 18 and 19, the exposed area of ​​the conductor 11 is gradually expanded in a direction intersecting the scanning direction. However, the present invention is not limited to this. The area where the insulating coating 12 has been thinned, in other words, the remaining area of ​​the thinned insulating coating 12, may be gradually expanded in a direction intersecting the scanning direction by scanning similar to that shown in FIGS. 18 and 19. In this case, the remaining area can be removed by the method of the first embodiment or the method of this embodiment, thereby exposing the conductor 11. The remaining area may be expanded multiple times.

[0139] 18 and 19, the thickness of the insulating coating 12 to be removed and the thickness of the remaining region can be varied by setting various conditions. Furthermore, the inventors' extensive research has revealed that, in this case, from the viewpoint of suppressing variations in the thickness of the remaining region, the overlap ratio α is preferably 1 / 4 or more, and from the viewpoint of suppressing the time required to remove the insulating coating 12, the overlap ratio α is preferably 5 / 6 or less. In other words, when the overlap ratio α is 1 / 4 or more and 5 / 6 or less, it is possible to suppress deterioration in quality and increase in the required time.

[0140] [Third embodiment] 22 and 23 are explanatory diagrams showing a coating removal method of a third embodiment, and are front views of an electric wire 10 viewed in the axial direction. As shown in FIGS. 22 and 23, the electric wire 10 has a rectangular (quadrilateral) cross section and is specifically configured as a rectangular wire. In the above embodiment, the electric wire 10 was set in a position where the surface 10a (side surface) was perpendicular to the traveling direction of the laser light L (the opposite direction to the Z direction). Therefore, if the electric wire 10 is a rectangular wire having four surfaces 10a, the electric wire 10 needs to be set four times with respect to the optical head 120 in different positions so that each of the four surfaces 10a is perpendicular to the opposite direction of the Z direction.

[0141] In contrast, in this embodiment, as shown in FIG. 22, the central axis Ax of the electric wire 10 is positioned at a distance from the optical head 120 in the opposite direction of the Z direction, and two adjacent surfaces 10a1 and 10a2 are tilted with respect to the Z direction so that the laser light L can be irradiated from the optical head 120 to the two surfaces 10a1 and 10a2. In the case of FIG. 22, the surfaces 10a1 and 10a2 are positioned at positions rotated by a predetermined angle (however, different angles) about the central axis Ax with respect to a plane (a plane parallel to the imaginary plane Vp) perpendicular to the opposite direction of the Z direction. In this case, the insulating coating 12 to be removed is a region covering the surfaces 10a1 and 10a2 and the corners 10b1 and 10b2 adjacent to the surfaces 10a1 and 10a2. The opposite direction of the Z direction is an example of a first direction.

[0142] 22, the three corners 10b (ridge lines) adjacent to the two surfaces 10a1 and 10a2 include a corner 10b1 between the two surfaces 10a1 and 10a2 and two corners 10b2 spaced apart from the corner 10b1. The corner 10b2 is located on the opposite side of the surfaces 10a1 and 10a2 from the corner 10b1. The electric wire 10 is set so that the positions z1 of the two corners 10b2 in the Z direction are approximately the same and the position zf of the focal point of the laser light L is between the position z2 of the corner 10b1 in the Z direction and the position z1, for example, at the center between the positions z1 and z2.

[0143] After the insulating coating 12 is removed from the surfaces 10a1 and 10a2 in state S1 of FIG. 22 , the wire 10 is rotated 180° about the central axis Ax, and the insulating coating 12 is removed from the surfaces 10a3 and 10a4 in state S2 of FIG. 23 . In this case, as in the case of FIG. 22 , the three corners 10b (ridge lines) adjacent to the two surfaces 10a3 and 10a4 include a corner 10b1 between the two surfaces 10a3 and 10a4 and two corners 10b2 away from the corner 10b1. The corner 10b2 is located on the opposite side of the surfaces 10a3 and 10a4 from the corner 10b1. In the position of FIG. 23 , the insulating coating 12 to be removed is the region covering the surfaces 10a3 and 10a4 and the corners 10b1 and 10b2 adjacent to the surfaces 10a3 and 10a4. The corner 10b2 is located on the opposite side of the surfaces 10a3 and 10a4 from the corner 10b1. The electric wire 10 is set so that the positions z1 of the two corners 10b2 in the Z direction are approximately the same, and the position zf of the focal point of the laser light L is between the position z1 and the position z2 of the corner 10b1 in the Z direction, for example, at the center between the positions z1 and z2.

[0144] According to this embodiment, the electric wire 10 only needs to be set twice relative to the optical head 120, in states S1 (FIG. 22) and S2 (FIG. 23), which are different postures from each other. This reduces the number of times the electric wire 10 is set, thereby providing the advantage of reducing the effort and time required for removing the coating.

[0145] Here, positions z1 and z2 are preferably set so as to be located within a distance of ±3 mm or less from position zf, which is the focal position in the traveling direction (in this case, approximately the opposite direction to the Z direction) of the laser light L. In other words, it is preferable to position the insulating coating 12 within a range of ±3 mm or less from the focal position in the traveling direction of the laser light L. This is because if the distance from position zf, which is the focal position, exceeds this distance, the effect of increasing the power density will be reduced.

[0146] 22, the minimum angular difference θ2 of the acute angle between the normal direction N2 of surface 10a2 and the Z direction is greater than the minimum angular difference θ1 of the acute angle between the normal direction N1 of surface 10a1 and the Z direction. In this case, the thickness of insulating coating 12 in the Z direction on surface 10a2 is greater than the thickness of insulating coating 12 in the Z direction on surface 10a1. Therefore, when laser light L is irradiated under the same irradiation conditions, it may be difficult to remove insulating coating 12 from surface 10a2.

[0147] Therefore, the power density in the imaginary plane Vp of the laser light L irradiating the surface 10a2 (hereinafter, the power density in the imaginary plane Vp will be simply referred to as the irradiation power density) may be made higher than the irradiation power density of the laser light irradiating the surface 10a1. The difference between the irradiation power density for the surface 10a1 and the irradiation power density for the surface 10a2 can be obtained, for example, by varying the power of the laser light L, varying the scanning pitch in the Y direction, or varying the scanning speed in the Y direction. The irradiation power density increases as the power of the laser light L increases, as the scanning pitch in the Y direction decreases, and as the scanning speed in the Y direction decreases.

[0148] 23, the minimum angular difference θ4 of the acute angle between the normal direction N4 of surface 10a4 and the Z direction is larger than the minimum angular difference θ3 of the acute angle between the normal direction N3 of surface 10a3 and the Z direction. In this case, the irradiation power density of the laser light L irradiating surface 10a4 may be larger than the irradiation power density of the laser light irradiating surface 10a3.

[0149] Furthermore, because the thickness of the insulating coating 12 in the Z direction at the corner 10b2 is thicker than the thickness of the insulating coating 12 in the Z direction at the surfaces 10a1, 10a2, 10a3, and 10a4, it may be difficult to remove the insulating coating 12 at the corner 10b2 when the laser light L is irradiated under the same irradiation conditions as the surfaces 10a1, 10a2, 10a3, and 10a4. Therefore, the irradiation power density of the laser light L irradiated to the corner 10b2 may be greater than the irradiation power density of the laser light L irradiated to the surfaces 10a1, 10a2, 10a3, and 10a4. The irradiation power density of the laser light L irradiated to the corner 10b1 may be smaller than the irradiation power density of the laser light L irradiated to the surfaces 10a1, 10a2, 10a3, and 10a4.

[0150] [Fourth embodiment] FIG. 24 is a perspective view of a portion of a coating removal apparatus 100C (100) according to a fourth embodiment. As shown in FIG. 24, in this embodiment, the electric wire 10 is rotated about a central axis Ax extending in the axial direction by a rotary support device 200, thereby scanning the surface 10a of the electric wire 10 with a laser beam L. This rotation allows the beam (spot) of the laser beam L to scan the width direction of the electric wire 10. The movement of the laser beam L in the axial direction of the electric wire 10 can be achieved by moving the optical head 120 using a drive mechanism 150 (see FIG. 2) or by changing the irradiation position on the electric wire 10 using a laser scanner 126 (see FIG. 2). Alternatively, the movement of the beam of laser beam L in the axial direction of the electric wire 10 may be achieved by a mechanism provided in the rotary support device 200 for moving the electric wire 10 in the axial direction, a mechanism for moving the rotary support device 200 itself in the axial direction, or the like. These moving mechanisms are examples of scanning mechanisms. The rotary support device 200 may also be referred to as a support device having a rotary mechanism.

[0151] Even with this configuration, the same effects as those of the above embodiment can be obtained. Furthermore, according to this embodiment, the optical head 120 may not require the laser scanner 126. In this case, the optical head 120 and the laser processing apparatus 100 can be configured more inexpensively and more compactly than when the optical head 120 includes the laser scanner 126. Furthermore, the optical head 120 may include a laser scanner 126 capable of so-called uniaxial scanning, which is capable of reciprocating only in the axial direction. In this case, the optical head 120 and the laser processing apparatus 100 can be configured more inexpensively and more compactly than when the optical head 120 includes a laser scanner 126 capable of so-called biaxial scanning.

[0152] [Fifth embodiment] FIG. 25 is a plan view of an electric wire 10 illustrating an example of the procedure of the coating removal method of the fifth embodiment. In this embodiment, first, the insulating coating 12 is removed from the entire circumference of the longitudinal middle portion of the electric wire 10 by the method of the above-described embodiment, thereby exposing the conductor 11 (A11). Then, the conductor 11 is cut along a cutting line CL in the longitudinal middle portion of the exposed conductor 11, thereby separating the electric wire 10 in the longitudinal direction (A12). Note that the cutting of the conductor 11 along the cutting line CL may be performed by irradiating it with laser light L or by another means. According to this method, the insulating coating 12 at the ends of the two electric wires 10 can be removed more efficiently and quickly.

[0153] [Sixth embodiment] 26 is a plan view of an electric wire 10 illustrating an example of the procedure of the coating removal method of the sixth embodiment. In this embodiment, first, the ends 10c of two electric wires 10 are butted against each other, and the two electric wires 10 are arranged in a substantially straight line (A21). Then, by the method of the above-described embodiment, the insulating coating 12 is removed from the portions adjacent to the two ends 10c (A22). This method allows the insulating coating 12 at the ends of the two electric wires 10 to be removed more efficiently and quickly.

[0154] FIG. 27 is a side view of a laser processing apparatus 100E (100) that performs the coating removal method of this embodiment. The laser processing apparatus 100E of this embodiment includes two rotary support devices 200 that each support the electric wire 10 rotatably about the central axis Ax and that can rotate synchronously with each other. These two rotary support devices 200 may have the same configuration as those in the fourth embodiment (see FIG. 24). In this case, the rotation of the electric wire 10 about the central axis Ax allows the beam (spot) of laser light L to scan in the width direction of the electric wire 10. Note that the configuration in FIG. 27 is just an example, and scanning of the beam (spot) of laser light L in the width direction of the electric wire 10 may be performed by a laser scanner 126.

[0155] [Modified electric wires] 28 to 31 are front views showing modified examples of the electric wire 10 from which the insulating coating 12 is to be removed in the above embodiment. The electric wire 10 may have a substantially square cross-sectional shape as shown in FIG. 28. Note that the insulating coating 12 in the above embodiment can be removed from various electric wires 10 having different flattening ratios of the rectangular electric wire 10. The electric wire 10 may have a substantially circular cross-sectional shape as shown in FIG. 29, or a substantially sector-shaped cross-sectional shape as shown in FIG. 30. Note that the cross-sectional shape of the electric wire 10 is not limited to these and may have various shapes. Furthermore, as shown in FIG. 31, the electric wire 10 may be a so-called twisted wire in which a plurality of conductors 11 are twisted. Furthermore, the electric wire 10 may be drawn out from a wound coil, or may be separated into individual pieces.

[0156] 32 to 34 are views showing the vicinity of the end 10c of the electric wire 10 according to another modification, with FIGS. 32 and 33 being side views and FIG. 34 being a perspective view. As shown in FIGS. 32 to 34, the end 10c of the electric wire 10 may have a convex shape in which a portion closer to the central axis Ax protrudes in the X direction (longitudinal direction, axial direction) more than a portion further away. In the modification of FIG. 32, the end 10c has a triangular convex portion in side view, and in the modification of FIG. 33, the end 10c has a dome-shaped convex portion in side view. In the modification of FIG. 34, the end 10c has a convex portion that is triangular in side view in the Y1 direction and trapezoidal in side view in the Y2 direction. This configuration can prevent the end 10c from being shaded when irradiated with laser light L, making it difficult to remove the insulating coating 12. It should be noted that the end portion 10c only needs to have a convex shape that protrudes in the X direction, and the convex shape is not limited to those shown in FIGS. 32 to 34, and can be modified in various ways.

[0157] [Cover for supplying oxygen gas] 35 to 38 show a modified example in which the insulating coating 12 is removed while supplying oxygen gas Go, and the insulating coating 12 is covered except for the removal area with a cover 300. Covering the insulating coating 12 except for the removal area with the cover 300 prevents unnecessary fire spread, thereby more reliably removing only the desired removal area. If the insulating coating 12 is not covered with the cover 300, it may be difficult to increase the power density of the laser light L, for example, due to considerations of unnecessary fire spread. In this regard, covering with the cover 300 as in this modification eliminates the need to set conditions that take fire spread into account, and the insulating coating 12 to be removed can be removed more efficiently and quickly. Covering the area except for the removal area with the cover 300 is particularly effective when the insulating coating 12 is made of a material that is prone to fire spread, such as PEEK.

[0158] The cover 300 is preferably made of a material that is non-flammable and has relatively high thermal conductivity. Making the cover 300 from a material with relatively high thermal conductivity can prevent adverse effects of heat, such as thermal deformation, from occurring on the insulating coating 12. From this perspective, the material of the cover 300 may be a metal material, such as a copper-based material such as pure copper or a copper alloy, or an aluminum-based material such as pure aluminum or an aluminum alloy.

[0159] Fig. 35 illustrates a case where the insulating coating 12 is removed from the longitudinal end of the electric wire 10. Fig. 36 is a front view of Fig. 35 viewed in the axial direction. As shown in Fig. 36, a minute gap g is provided between the cover 300 and the electric wire 10 (insulating coating 12). Figs. 37 and 38 illustrate a case where the insulating coating 12 is removed from the longitudinal middle of the electric wire 10. In this case, as shown in Fig. 37, two covers 300 may be used that cover both longitudinal sides of the removal region, or a cover 300 provided with an opening 300a that exposes the removal region may be used.

[0160] The cover 300 may be installed on a device that holds the electric wire 10, such as the rotary support device 200. In this case, the electric wire 10 is inserted into the cover 300, the supply of oxygen gas Go is started, and while the oxygen gas Go is being supplied, the insulating coating 12 is removed by irradiating the electric wire 10 with laser light L. After the removal of the insulating coating 12 is complete, the supply of oxygen gas Go is stopped, and the electric wire 10 is removed from the cover 300. Thereafter, the next electric wire 10 is inserted into the cover 300, and the same process is performed.

[0161] 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 modified as appropriate.

[0162] For example, the laser device may combine and output laser beams from multiple light sources with different wavelengths between 400 nm and 550 nm. In this case, the laser device may have, for example, an internal diffraction grating, which combines and outputs the multiple laser beams with different wavelengths output from the multiple light sources. This configuration also enables output with a smaller beam diameter (spot diameter) and higher power density. Furthermore, this configuration provides, for example, a wider wavelength range of the laser beam compared to laser beams with a single wavelength, thereby increasing the light absorption rate even when the resin materials of the insulating coating are different, making it easier to ensure good removal of the insulating coating. Furthermore, since the focal positions of the multiple laser beams in the emission direction differ due to chromatic aberration of the lenses in the focusing optical system included in the optical head, the robustness of the distance between the optical head and the workpiece can be improved.

[0163] Alternatively, for example, the region from which the insulating film is to be removed may be divided into multiple regions (divided regions), and the insulating film may be removed for each divided region using the above-described method and procedure. In this case, the removal method, procedure, and conditions for the divided regions may be the same or different.

[0164] Alternatively, for example, the insulating film may be removed by spot irradiating different locations multiple times without scanning. [Industrial Applicability]

[0165] The present invention can be used in a coating removal method and a coating removal device. [Explanation of symbols]

[0166] 10...Electric wire 10a,10a1,10a2,10a3,10a4…Surface (side) 10b, 10b1, 10b2...Corner (ridge line) 10c...end 11...Conductor (core wire) 11a…Surface 11d...Discolored area 12...Insulating film (film) 12r…residue 12a...end face 12b…Step surface 100, 100A, 100C, 100E...Laser processing equipment (coating removal equipment) 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...Drive mechanism 160...Oxygen supply mechanism 161...Plumbing 161a...Discharge port 200...Rotation support device 300...Cover 300a...opening a,ar...Maximum value A...Predetermined range A00,A01,A1~A4…area Ar…2 Ax…center axis Bo…Boundary C...corner Ct…center CL…cutting line D...Distance d,dr…Diameter Go...oxygen gas Go_rd…Ingredients Go_z…ingredients g...gap P…Irradiation point Pr...Remaining site L...laser light N1~N4…Normal direction RD…Removal direction (second direction) S...Spot SD1, SD2...Scanning direction s1~s4...Scan Vp: Virtual plane W…width X…direction Y...direction Yo...opposite direction Z...direction (opposite to the first direction) z1,z2,zf…position α...overlap rate θ…Angle θ1~θ4…Minimum angle difference

Claims

1. 1. A coating removal method for removing a coating from an electric wire having a core wire and an insulating coating made of an organic polymer material, comprising: a step of placing the electric wire at a position where a surface of the electric wire can be irradiated with laser light; a removing step of removing the coating by irradiating each location of a target region of the surface of the electric wire with the laser light having a wavelength of 300 nm or more and 500 nm or less a plurality of times; A coating removal method comprising the steps of:

2. 1. A coating removal method for removing a coating from an electric wire having a core wire and an insulating coating made of an organic polymer material, comprising: a step of placing the electric wire at a position where a surface of the electric wire can be irradiated with laser light; a removing step of removing the coating by irradiating each location of a target region of the surface of the electric wire with blue laser light multiple times; A coating removal method comprising the steps of:

3. 1. A coating removal method for removing a coating from an electric wire having a core wire and an insulating coating made of an organic polymer material, comprising: a step of placing the electric wire at a position where a surface of the electric wire can be irradiated with laser light; a removing step of removing the coating by irradiating each location of a target region of the surface of the electric wire with the laser light having a wavelength of 300 nm or more and 600 nm or less, and having an absorptivity of 80% or more for the coating, multiple times; A coating removal method comprising the steps of:

4. 1. A coating removal method for removing a coating from an electric wire having a core wire and an insulating coating made of an organic polymer material, comprising: a step of placing the electric wire at a position where a surface of the electric wire can be irradiated with laser light; a removing step of removing the coating by irradiating each location of a target region of the surface of the electric wire with the laser light having a wavelength of 300 nm or more and 600 nm or less a plurality of times; and The removing step includes: a first step of burning and thinning the coating by energy imparted to the coating from the laser light; a second step of burning and removing the coating thinned in the first step by energy imparted to the core wire and the coating from the laser light.

5. the wavelength of the laser light is a wavelength at which the absorption rate of the coating is 80% or more, The removing step includes: a first step of burning and thinning the coating by energy imparted to the coating from the laser light; 2. The coating removal method according to claim 1, further comprising a second step of burning and removing the coating thinned in the first step by energy imparted to the core wire and the coating from the laser light.

6. The average power density of the laser light on the surface of the coating is 250 [kW / cm ２ ] or more and 650 [kW / cm ２ 6. The coating removal method according to claim 1, wherein the thickness of the coating is less than or equal to 100 μm.

7. The removing step includes: a first step of irradiating the surface of the electric wire with the laser light to thin the coating; a second step of irradiating the coating thinned in the first step with the laser light to remove the coating; The coating removal method according to claim 1 , comprising:

8. 8. The method for removing a film according to claim 4, wherein in the first step, the thickness of the film is set to 1 [mu]m or less.

9. 8. The coating removal method according to claim 4, wherein the energy amount of the laser light output in the first step is equal to or greater than the energy amount of the laser light output in the second step.

10. The coating removal method according to claim 5 or 7, wherein a power density at the focal position of the laser light in the second step is greater than a power density at the focal position of the laser light in the first step.

11. 8. The coating removal method according to claim 4, wherein at least one of the following is different between the first step and the second step: power density at the focal position of the laser light, power of the laser light, spot diameter of the laser light on the surface, scanning speed when the spot of the laser light is scanned on the surface, and amount of deviation when the spot of the laser light is scanned multiple times on the surface while being shifted in a direction intersecting the scanning direction.

12. The coating removal method according to any one of claims 1 to 3, wherein the removal step includes a step of irradiating a specific area of ​​the area from which the coating is to be removed with the laser light beam while scanning the laser light beam multiple times.

13. The coating removal method according to claim 12 , wherein, in the step of irradiating the specific region with the laser light beam while scanning the specific region multiple times, the scanning position is shifted in a direction intersecting the scanning direction.

14. The coating removal method according to claim 13, wherein the amount of deviation of the scanning position is equal to or greater than ⅓ and equal to or less than ½ of the width of the irradiation area in the scan.

15. The laser beam is scanned a plurality of times while being shifted in a direction intersecting the scanning direction, The coating removal method according to claim 12 , wherein the irradiation areas of two successive scans partially overlap each other in a direction intersecting the scanning direction.

16. The coating removal method according to claim 15, wherein an overlap rate of widths of irradiation regions between two successive scans is 1 / 4 or more.

17. The coating removal method according to claim 15, wherein an overlap ratio of widths of irradiation regions between two successive scans is 5 / 6 or less.

18. The coating removal method according to claim 17, wherein an overlap rate of widths of irradiation regions between two successive scans is equal to or greater than 1 / 4 and equal to or less than 5 / 6.

19. The removal step is performed when the power density at the focal position of the laser light is 230 [kW / cm ２ 6. The coating removal method according to claim 1, further comprising the step of irradiating the electric wire with a laser beam spot while scanning the electric wire in a state where the electric wire is in a state where the laser beam spot is greater than or equal to the thickness of the electric wire.

20. the removing step includes a step of irradiating a specific region of a region to be removed with the laser light beam while scanning the specific region, multiple times; In the final step of the multiple steps, the power density at the focal position of the laser light is 230 [kW / cm ２ 4. The coating removal method according to claim 1, wherein the electric wire is irradiated with a laser beam spot while scanning the electric wire in a state where the electric wire is in a state where the laser beam spot is greater than or equal to the thickness of the electric wire.

21. 6. The coating removal method according to claim 1, wherein the wavelength of the laser light is 400 nm or more.

22. In the removal step, the power density at the focal position of the laser light is 350 [kW / cm ２ 6. The coating removal method according to claim 1, wherein the coating removal rate is at least 1000 ppm.

23. 6. The coating removal method according to claim 1, wherein in the removing step, the diameter of the laser beam at the focal position is 500 μm or less.

24. 24. The coating removal method according to claim 23, wherein in the removing step, the beam diameter at the focal position of the laser light is 200 [μm] or more.

25. 24. The coating removal method according to claim 23, wherein the diameter of the beam at the focal position of the laser light is not less than 300 [μm] and not more than 400 [μm].

26. 6. The coating removal method according to claim 1, wherein the laser light is a continuous wave laser.

27. the laser light is output from one laser module, 6. The coating removal method according to claim 1, wherein the power of the one laser module is 400 W or more.

28. 28. The coating removal method according to claim 27, wherein the power of the one laser module is 1 kW or less.

29. 6. The coating removal method according to claim 1, wherein the spot of the laser light is scanned using a laser scanner.

30. 6. The coating removal method according to claim 1, wherein the spot of the laser light is scanned by rotating the electric wire about a central axis extending in the axial direction of the electric wire.

31. 6. The coating removal method according to claim 1, wherein the spot of the laser light is scanned using a laser scanner, and the spot of the laser light is scanned by rotating the electric wire around a central axis extending in the axial direction of the electric wire.

32. The ends of two electric wires, each of which is the electric wire, are butted together to be arranged in a substantially straight line; The coating removal method according to any one of claims 1 to 5, wherein the coating is removed from a portion adjacent to the end portions of the two electric wires.

33. removing the coating from a longitudinally intermediate portion of the electric wire; 6. The coating removal method according to claim 1, wherein the electric wire is cut into two pieces in the longitudinal direction at a midpoint in the longitudinal direction of the section from which the coating has been removed.

34. The laser light is output from an optical head, a central axis of the electric wire is disposed at a position spaced apart from the optical head in a first direction; 6. A film removal method according to claim 1, wherein the film to be removed is positioned within a range of ±3 mm or less in the first direction relative to the focal position of the laser light.

35. The laser light is output from an optical head, the electric wire has a plurality of side surfaces extending in a longitudinal direction and a plurality of ridge lines as corner portions extending in the longitudinal direction between two adjacent side surfaces, irradiating the coating with the laser light in a position where one of the plurality of ridgelines and two side surfaces on both sides of the ridgeline face the optical head; A coating removal method described in any one of claims 1 to 5, wherein the coating that constitutes the one ridge line, the two side surfaces, and the ridge line adjacent to each of the two side surfaces on the opposite side of the one ridge line is targeted for removal.

36. a central axis of the electric wire is disposed at a position spaced apart from the optical head in a first direction; the two side surfaces are arranged in positions in which a plane perpendicular to the first direction is rotated by a predetermined angle around the central axis, and the two side surfaces are arranged in positions in which the minimum angular difference between the normal direction of the two side surfaces and the direction opposite to the first direction is different from each other; The coating removal method according to claim 35 , wherein the power density in an imaginary plane perpendicular to the first direction of the laser light irradiated onto the side surface is increased as the minimum angle difference increases.

37. a central axis of the electric wire is disposed at a position spaced apart from the optical head in a first direction; The coating removal method of claim 35, wherein the power density in a virtual plane perpendicular to the first direction of the laser light irradiated onto an adjacent ridge line on the opposite side of the side surface from the one ridge line is made higher than the power density in the virtual plane of the laser light irradiated onto the one ridge line and the two side surfaces.

38. 20. The coating removal method according to claim 19, wherein the end of the electric wire has a convex shape that protrudes in the longitudinal direction of the electric wire.

39. 6. The film removal method according to claim 1, wherein the film is removed while supplying oxygen in the removing step.

40. In the removing step, the removed region of the coating expands in a second direction, The coating removal method according to claim 12 , wherein oxygen is supplied in a direction including a component in the second direction.

41. The coating removal method according to claim 12 , wherein the scanning direction of the beam is changed over time in the removing step.

42. The coating removal method according to claim 12, wherein in the removing step, the beam moves on the surface while folding back or spiraling so that the removed area of ​​the coating gradually expands in at least a portion of the scanning of the beam.

43. The coating removal method according to claim 12 , wherein the irradiation power of the laser light per unit area of ​​the surface is changed during scanning of the beam to remove the coating.

44. 44. The coating removal method according to claim 43, wherein in the removing step, the irradiation power of the laser light per unit area of ​​the surface is reduced during the process of scanning the beam to remove the coating.

45. 44. The coating removal method according to claim 43, wherein the removal step changes the irradiation power of the laser light per unit area of ​​the surface by changing at least one of the scanning speed of the laser light and the output of the light source of the laser light.

46. The coating removal method according to claim 12 , wherein in the removing step, the electric wire and the beam move relatively in the axial direction of the electric wire in at least a part of a scanning section of the beam.

47. The coating removal method according to claim 12 , wherein in the removing step, the electric wire and the beam move relatively in a direction intersecting an axial direction of the electric wire in at least a part of a scanning section of the beam.

48. The coating removal method according to any one of claims 1 to 5, wherein the core wire is made of a copper-based metal material.

49. The coating removal method according to any one of claims 1 to 5, wherein the electric wire is a rectangular wire or a round wire.

50. The coating removal method according to claim 12 , wherein in the removing step, the coating remains in a round before the final round of irradiation at each location among the multiple rounds of irradiation.

51. 40. The coating removal method according to claim 39, wherein in the removing step, an area of ​​the coating that is not to be removed is covered with a cover.

52. a laser device that outputs laser light; an optical head that irradiates the laser light output from the laser device onto a surface of an electric wire having a core wire and a coating made of an organic polymer material; Equipped with removing the coating by irradiating each location of the surface in a region that is to be removed with the laser light a plurality of times; The wavelength of the laser light is 500 nm or less.

53. The wavelength of the laser light is 300 nm or more, The power density at the focal position of the laser light is 2.3 [kW / mm ２ 53. The coating removal device according to claim 52, wherein:

54. the laser light is output from one laser module included in the laser device, 54. The coating removal device of claim 53, wherein the power of the one laser module is 150 W or more.

55. an optical fiber that propagates the laser light output from the laser module to the optical head; 55. The coating removal device according to claim 54, wherein the core diameter of the optical fiber is 200 [μm] or less.

56. 54. The coating removal device according to claim 53, wherein the laser device combines and outputs a plurality of laser beams having different wavelengths in the range of 300 nm to 600 nm.

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