JP2012110945A - Laser beam machining apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus that controls a damage of an apparatus, which is caused by reflected light from a workpiece.SOLUTION: The laser beam machining apparatus includes: a laser source; a laser illumination head that is mounted with a condenser lens for condensing a laser beam and irradiates the workpiece with the laser beam; a laser transmission device for transmitting the laser beam from the laser source to the laser illumination head; an antioxidant gas feeding device for feeding antioxidant gas for preventing the workpiece from being oxidized by laser illumination; and a light shield that is interposed between the laser illumination head and the workpiece, disposed in the laser illumination head so as to encircle a part of the workpiece to which the laser beam is irradiated, can change a form thereof according to a variation in distance between the laser illumination head and the workpiece and formed of either a metal, ceramic or carbon.

Description

  Embodiments described herein relate generally to a laser processing apparatus.

  The construction process using laser light as an energy source is used for various purposes such as welding, cutting, surface material modification, and stress improvement. In any case, construction is performed by condensing the laser light with an optical element such as a lens. It is common to irradiate an object with a higher spatial energy density. When laser light is used as a heat source for heating processes such as welding, cutting, and surface material modification, the material to be applied is heated and melted from its surface by absorbing a certain percentage of the energy of the irradiated laser light. And realize a desired construction process. Since the absorption rate of laser light on the material surface depends on the material, the wavelength of the laser used, the energy density, the irradiation angle, etc., these parameters are used in order to obtain an appropriate construction result in the intended construction process. Accordingly, the laser light source for irradiating appropriately and its output are adjusted.

  Laser light that is not absorbed by the material is reflected (or scattered), but its energy may be twice or more that of laser light that is absorbed by the material. When high-energy reflected light returns into the laser irradiation head, which is an end effector, the metal fixture for fixing the internal optical element may be heated and damaged, resulting in damage to the optical element itself.

  In recent years, the optical fiber, which has been the mainstream of laser beam transmission means, is very thin, and the resin buffer layer and coating layer are vulnerable to heat. For this reason, in order to prevent damage to the device due to reflected light, a pinhole-like component is arranged in the optical path inside the lens barrel of the laser irradiation head for emitting laser light, thereby reflecting the reflected light outside the effective diameter of the optical system. There is known a method for preventing the incident light from entering (see, for example, Patent Document 1).

  In addition, for example, a method is known in which the reflected light direction is not aligned with the axis of the emitted laser light by tilting the irradiation angle of the laser light so that the reflected light is released from the laser irradiation head. (For example, refer to Patent Document 2).

Japanese Patent No. 4155589 JP 2000-56070 A

  As described above, when pinhole-shaped components are arranged in the optical path, the pinhole diameter does not play the role of transmitting a beam unless the pinhole diameter is large enough due to component tolerances and optical system adjustment errors. Therefore, it is impossible to completely prevent the optical fiber coating material and the optical element fixing bracket from being damaged.

  Further, when the irradiation angle of the laser beam is inclined, the reflected light does not return to the laser irradiation head, and the risk of damage can be reduced. However, a gap with a certain distance is required between the tip of the laser irradiation head that emits laser light and the object to be processed in order to follow the unevenness and grooved shape of the surface to be processed. is there. For this reason, the reflected light that has not returned to the light guide path in the laser irradiation head leaks to the surroundings without being blocked by the nozzle or the like, and causes damage to, for example, an electric wire attached to the apparatus or an inert gas supply tube. . In particular, in an application example such as a remote welding apparatus in which the apparatus is miniaturized, the devices are arranged at high density in a narrow space, and the number of parts that need countermeasures against damage increases.

  The present invention has been made in response to the above-described conventional circumstances, and an object of the present invention is to provide a laser processing apparatus that can suppress damage to the apparatus due to reflected light from a construction object.

  The laser processing apparatus of the embodiment is equipped with a laser light source that generates laser light, a condensing lens for condensing the laser light, and a laser irradiation head for irradiating the workpiece with the laser light; Antioxidant gas for supplying laser light transmitting means for transmitting the laser light from the laser light source to the laser irradiation head and an antioxidizing gas for preventing oxidation of the workpiece due to the irradiation of the laser light The laser irradiation head is disposed between the supply device, the laser irradiation head and the workpiece, and surrounds the irradiation portion of the laser beam of the workpiece; and It is possible to deform according to a change in the distance between the laser irradiation head and the workpiece, and includes a light shielding body made of any one of metal, ceramics, and carbon. That.

The figure which shows schematic structure of the laser processing apparatus which concerns on 1st Embodiment. The figure which shows the principal part schematic structure of the laser processing apparatus of FIG. The figure which expands and shows the principal part schematic structure of the laser irradiation head of FIG. The figure which shows schematic structure of the absorption plate of the laser irradiation head of FIG. The figure which expands and shows the structure of the light shielding wire of the laser irradiation head of FIG. The figure which shows the principal part schematic structure of the laser processing apparatus which concerns on 2nd Embodiment. The figure which shows schematic structure of the absorption plate of the laser irradiation head of FIG. The figure which shows the principal part schematic structure of the laser processing apparatus which concerns on 3rd Embodiment. The figure which shows schematic structure of the absorption plate of the laser irradiation head of FIG. The figure which shows schematic structure of the laser processing apparatus which concerns on 4th Embodiment. The figure which shows the principal part schematic structure of the laser processing apparatus of FIG. The figure for demonstrating the use condition of the laser processing apparatus of FIG. The figure which shows the principal part structure of a modification. The figure which shows the principal part structure of a modification. The figure which shows the example of a groove shape. The figure which shows the example of a groove shape. The figure which shows the principal part structure of a modification. The figure which shows the example of a groove shape. The figure which shows the example of a groove shape. The figure for demonstrating the irradiation angle of a laser beam.

  Hereinafter, embodiments of a laser processing apparatus will be described with reference to the drawings.

  1 and 2 are diagrams showing a schematic configuration of the laser processing apparatus according to the first embodiment. This laser processing apparatus is a laser processing apparatus suitable for remotely performing clad welding on the inner surface of a pipe. .

  As shown in FIG. 1, the construction apparatus 100 is equipped with the laser irradiation head 1, is inserted into the pipe 8, and is fixed in the pipe 8 by the fixing mechanism 105. The construction apparatus 100 includes a Z-axis drive device 101 for moving the laser irradiation head 1 in the axial direction of the pipe 8, a θ-axis drive device 102 for moving in the circumferential direction, and an R-axis drive device for moving in the radial direction. 103 is installed. Moreover, the construction apparatus 100 is equipped with a ψ-axis drive device 104. This ψ-axis drive device 104 is a device for adjusting the laser irradiation angle ψ (tilt direction) of the laser irradiation head 1.

  Each drive unit includes actuators such as electromagnetic motors, ultrasonic motors, hydraulic motors, rotation / position detection sensors such as encoders, resolvers, limit switches, power transmission parts such as gears, racks / pinions, pulleys, belts, It consists of sliding and bearing parts such as linear guides and bearings. Moreover, the construction apparatus 100 is equipped with a filler wire supply mechanism (not shown), and a filler wire is supplied from a filler wire drum (not shown) by an actuator. A control wire 6 is connected to the construction apparatus 100 for electrical components such as these actuators and sensors.

  The laser irradiation head 1 has an optical fiber 5 for transmitting laser light and a gas supply tube 7 for supplying an antioxidant gas sprayed in the vicinity of a molten pool 201 (see FIG. 2) in order to prevent oxidation during welding. Is connected. The optical fiber 5, the control wire 6, and the gas supply tube 7 are connected to the laser oscillator 2, the robot control panel 3 and the antioxidant gas supply device 4 installed on the platform 9 away from the pipe 8. Clad welding is possible.

  FIG. 2 schematically shows a schematic configuration of the laser irradiation head 1 in the first embodiment shown in FIG. As shown in FIG. 2, the laser irradiation head 1 includes a lens barrel 20. An optical fiber 5 for transmitting laser light is connected to the rear end side (upper side in FIG. 2) of the lens barrel 20 via a fiber connector 23 so that attachment / detachment is easy.

  A nozzle 22 is disposed on the distal end side of the lens barrel 20. A collimating lens 25, a condensing lens 26, and a window 27 are disposed in the lens barrel 20 in this order from the rear end side. The window 27 is for preventing the optical system such as the condenser lens 26 from being damaged by sputtering from the molten pool 201 or the like.

  Laser light emitted from the optical fiber 5 is converted into parallel light by the collimator lens 25, collected by the condenser lens 26, and then passed through the window 27 and the nozzle 22 to irradiate the work surface 10 as a condensed beam 202. The A constant interval is formed between the work surface 10 and the nozzle 22 from which the focused beam 202 is emitted, and as a result, irregularities and grooved shapes of the work surface 10 are formed. Can be followed. The focused beam 202 is focused on within the nozzle 22 and then irradiated on the surface to be processed 10, so that the focused surface 202 is irradiated with the same beam diameter on the surface to be processed 10 without focusing on the nozzle 22. The inner diameter of 22 can be reduced.

  A gas supply tube 7 for supplying an antioxidant gas is connected to a side wall portion of the lens barrel 20 via an attachable / detachable gas tube connector 24. The antioxidant gas supplied from the gas supply tube 7 into the lens barrel 20 passes through the nozzle 22 and the gas flow path 28 of the antioxidant gas provided at the attachment portion of the window 27, passes through the nozzle 22, and the work surface 10. Of the condensed beam 202 is supplied in the vicinity of the irradiated portion.

  In the clad welding, when the focused surface 202 is irradiated on the work surface 10, the material of the pipe 8 is melted to form the molten pool 201, and a filler wire (not shown) is supplied to form a weld overlay. An antioxidant gas is supplied from the nozzle 22 to prevent oxidation of the weld overlay.

  A plate-shaped absorbing plate 21 made of an absorbing material that absorbs laser light is attached to the tip portion of the nozzle 22. As the absorption plate 21, a surface coated to improve the absorptance of the reflected light 205, for example, a thermal sprayed ceramic such as tungsten carbide or silicon carbide can be used.

  In this way, by arranging the absorbing plate 21, the reflected light 205 of the laser light irradiated on the work surface 10 is absorbed at a position where the energy density is high, so that most of the energy can be absorbed. This makes it possible to prevent damage to equipment inside and outside the laser irradiation head 1 due to the reflected light 205. The energy of the reflected light 205 is absorbed by the absorption plate 21 and becomes heat. For this reason, a refrigerant flow path for circulating a refrigerant for recovering heat may be provided in the absorption plate 21.

  Further, a light shielding body 30 is disposed on the peripheral edge of the absorbing plate 21. The light shield 30 is disposed so as to be interposed between the laser irradiation head 1 (absorbing plate 21) and the work surface 10 of the workpiece, and the laser of the work surface 10 of the work piece. It arrange | positions so that the circumference | surroundings of the irradiation site | part of light may be enclosed.

  Further, the light shield 30 can be deformed in accordance with a change in the distance between the laser irradiation head 1 and the work surface 10 of the work piece. Not only the reflected light 205 is generated from the work surface 10, but also scattered light 206 from the surface of the molten pool 201 in which the metal has melted. The energy of the reflected light 205 that has not been absorbed by the absorbing plate 21 becomes double reflected light 207. The light shielding body 30 is disposed in order to absorb these energy and prevent leakage. For this reason, the light shielding body 30 needs to have heat resistance, and is comprised from either a metal, ceramics, carbon, a metal fiber, a ceramic fiber, and a carbon fiber. In FIG. 2, reference numeral 203 denotes a construction part normal axis on the construction surface 10, and ψ1 denotes an angle formed by the construction part normal axis 203 and the beam irradiation axis 204.

  3 to 5 are enlarged views showing the configuration of the light shielding body 30 shown in FIG. Among these, FIG. 3 is an enlarged view of the tip side from the nozzle 22. As shown in FIG. 3, the light shielding body 30 in the first embodiment includes a light shielding wire 51.

  FIG. 4 is a diagram schematically illustrating a state in which the absorption plate 21 is viewed from the bottom surface side. As shown in FIG. 4, a plurality of light shielding wires 51 are attached in a brush-like row having an angle φ1 with the surface of the absorption plate 21, and this angle φ1 is from the root toward the tip of the absorption plate 21. The acute angle is 90 ° or less from the outer edge toward the center.

  In order to prevent the scattered light 206 and the double reflected light 207 from leaking, the light shielding wire 51 is pressed against the work surface 10 by the R-axis drive device 103 shown in FIG. At the same time, the work surface 10 is rubbed. For this reason, it is preferable to use a flexible material for the light shielding wire 51. In this case, when a metal single wire is used, the outer diameter is desirably 1.5 mm or less, and when a rope-shaped wire in which metal strands are twisted is used, the outer diameter of the rope is 2.0 mm. The following is desirable.

  In the first embodiment, the light shielding wire 51 is made of highly corrosive stainless steel and has a rope shape with an outer diameter of 1 mm in which wire strands 53 are twisted as shown in FIG. More flexible than single wire. The light shielding wire 51 is arranged in a brush shape and attached to the absorbing plate 21, and the wire tip 52 is processed into a spherical shape. In FIG. 4, only a part of the light shielding wire 51 is shown, but actually, the light shielding wire 51 is arranged in an annular shape along the entire peripheral edge of the absorbing plate 21.

  In the light shielding wire 51 configured in this way, in addition to its flexibility, the wire tip 52 is spherical, so that it can be prevented from being caught by the unevenness of the surface 10 to be processed. It is possible to prevent the operation of the apparatus from being hindered by being caught on the unevenness or the like, or the light shielding wire 51 itself from being damaged.

  Further, by providing the light shielding wire 51 with the angle φ1 described above, the direction in which the light shielding wire 51 is deformed by being pressed is determined in the central direction of the absorbing plate 21, so that the light shielding wires 51 are not dispersed. The light shielding effect can be enhanced. Further, by not making the angle φ1 an obtuse angle of 90 ° or more, the wire tip 52 of the light shielding wire 51 does not jump out of the absorbing plate 21, and the size of the apparatus can be reduced to a small size.

  As shown in FIGS. 3 and 4, the absorbing plate 21 has a plate shape surrounding the entire periphery of the nozzle 22, and a beam irradiation port 29 connected to the nozzle 22 is disposed at the center thereof. A cooling gas flow path 46 is provided in the absorption plate 21 so as to surround the beam irradiation port 29 as a center.

  As shown in FIG. 3, the absorption plate 21 is provided with a plurality of cooling gas nozzles 47 in communication with the cooling gas flow path 46, and is the same component as the antioxidant gas from a cooling gas supply device (not shown). The gas 208 is supplied from the cooling gas tube 44 connected to the absorption plate 21 by the cooling gas tube connector 45 and is jetted toward the light shielding wire 51, thereby cooling the light shielding wire 51.

  As the material of the light shielding wire 51, a metal, for example, copper, gold, silver, tungsten having a high melting point, or the like having high thermal conductivity, or ceramics, for example, alumina, silicon oxide, glass, or carbon having a high melting point is used. be able to. By using a material having a high melting point, the light shielding wire 51 itself can be prevented from being damaged even when exposed to strong scattered light 206 or the like for a long time. In addition, by using a material having high thermal conductivity, heat can be easily conducted to the absorption plate 21, and the effect of forced cooling by the cooling gas 208 is improved, and when exposed to strong scattered light 206 or the like for a long time. In this case, the light shielding wire 51 itself can be prevented from being damaged.

  According to the first embodiment configured as described above, the light shielding body 30 absorbs scattered light 206 such as irregular reflection due to a change in the shape of the work surface 10, double reflected light 207 from the absorbing plate 21, and the like. Thus, it is possible to prevent leakage to the outside, and thus it is possible to prevent equipment outside the laser irradiation head 1 from being damaged.

  Next, a second embodiment will be described with reference to FIGS. In the second embodiment, parts corresponding to those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 6 shows an enlarged view of the tip side from the nozzle 22 of the second embodiment, and FIG. 7 shows a state where the absorption plate 21 is viewed from the bottom side. As shown in FIGS. 6 and 7, in the second embodiment, a plurality of light shielding pins 54 are used as the light shielding body 30 described above.

  The light shielding pin 54 is inserted and locked in a pin hole 57 formed in the absorption plate 21, and a cylinder 56 in which a coil spring 55 is accommodated on the upper surface side of the absorption plate 21 corresponding to the pin hole 57. Is arranged. The light shielding pin 54 is biased toward the work surface 10 by the coil spring 55.

  The front end portion of the light shielding pin 57 has a spherical shape, and the spherical front end portion is in contact with the work surface 10 while being biased by the coil spring 55. Thus, by bringing the light shielding pin 54 into contact with the work surface 10 to some extent, the light shielding pin 54 is always in contact with the work surface 10 by the expansion and contraction of the coil spring 55 regardless of the unevenness of the work surface 10. It has a configuration that can be maintained. Moreover, in order to improve followability with the shape of the work surface 10, the diameter of the light shielding pin 54 may be reduced, and the arrangement may be three or more instead.

  As shown in FIG. 7, the light shielding pins 54 are arranged in two rows concentrically around the position of the beam irradiation port 29. Further, the outer light shielding pins 54 are arranged so as to be positioned in a portion between the inner light shielding pins 54 so that the scattered light 206 does not leak outside. The light shielding pins 54 may be arranged in two rows concentrically around the position of the laser irradiation spot 200.

  An annular cooling gas passage 46 is formed in the absorption plate 21 so as to be positioned further inside the inner light shielding pin 54. As shown in FIG. 6, a cooling gas nozzle 47 is formed on the absorption plate 21 so that the gas flow path 46 and the pin hole 57 communicate with each other. Thereby, the cooling gas which is the same component as the antioxidant gas is sprayed toward each light shielding pin 54, and the light shielding pin 54 is cooled.

  The material of the light shielding pin 54 may be a metal having high thermal conductivity, for example, copper, gold, silver, tungsten having a high melting point, etc., and only the spherical tip contacting the work surface 10 has wear resistance. High stainless steel may be used. Moreover, ceramics, for example, alumina having a high melting point, silicon oxide, glass, or carbon can be used.

  According to the second embodiment configured as described above, the light shield 30 absorbs the scattered light 206 such as irregular reflection due to the shape change of the work surface 10, the double reflected light 207 from the absorption plate 21, and the like. Thus, it is possible to prevent leakage to the outside, and thus it is possible to prevent equipment outside the laser irradiation head 1 from being damaged.

  Next, a third embodiment will be described with reference to FIGS. In the third embodiment, parts corresponding to those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 8 shows an enlarged view of the tip side from the nozzle 22 of the third embodiment, and FIG. 9 shows a state in which the absorption plate 21 is viewed from the bottom side. As shown in FIGS. 8 and 9, in the third embodiment, a light shielding sheet 58 is used as the light shielding body 30.

  A light shielding sheet 58 stretched like a sail in a tensioned state is attached to the absorbing plate 21 by a plurality of leaf springs 59 curved in a semicircular shape. The light shielding sheet 58 is pressed against the work surface 10 to some extent so that the leaf spring 59 is elastically deformed. As a result, the light shielding sheet 58 always follows the unevenness of the work surface 10. The state in contact with the construction surface 10 is maintained. In order to perform the same function, for example, a coil spring can be used instead of the leaf spring 59. In FIG. 9, only a part of the light shielding sheet 58 is illustrated, but actually, the light shielding sheet 58 is annularly disposed along the entire periphery of the peripheral edge of the absorbing plate 21.

  As a material of the light shielding sheet 58, considering heat resistance, for example, ceramic fibers such as alumina, silicon oxide, and glass having a high melting point, carbon fibers excellent in thermal conductivity, and fine metal wires such as tungsten and copper Can be used in the form of a woven or non-woven sheet.

  According to the third embodiment configured as described above, the light shielding body 30 absorbs scattered light 206 such as irregular reflection due to a shape change of the work surface 10, double reflected light 207 from the absorbing plate 21, and the like. Thus, it is possible to prevent leakage to the outside, and thus it is possible to prevent equipment outside the laser irradiation head 1 from being damaged.

  Next, a fourth embodiment will be described with reference to FIGS. Note that in the fourth embodiment, portions corresponding to those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 10 shows the overall configuration of the fourth embodiment, and FIG. 11 shows the configuration of the laser irradiation head 1. As shown in FIGS. 10 and 11, the fourth embodiment remotely performs clad welding of the inner surface of a pipe in water.

  As shown in FIG. 10, in 4th Embodiment, the construction apparatus 100 which mounted the laser irradiation head 1 in the piping 8 connected to the water tank 11 filled with the water 12 is inserted and fixed. The laser oscillator 2, the robot control panel 3, and the antioxidant gas supply device 4 are installed on a platform 9 outside the water tank 11, and are connected to the laser irradiation head 1 by an optical fiber 5, a control wire 6, and a gas supply tube 7.

  A fiber connector 23 for connecting the optical fiber 5 shown in FIG. 11 to the lens barrel 20 and a gas tube connector 24 for connecting the gas supply tube 7 to the lens barrel 20 have a watertight structure. An annular sealing skirt 60 is disposed so as to be positioned outside the light shielding body 30.

  The sealing skirt 60 is made of a flexible material, for example, a resin such as silicon rubber, polyurethane, or neobutyl rubber. The sealing skirt 60 is for forming a watertight space 13 between the absorbing plate 21 and the work surface 10, and the front end side of the sealing skirt 60 is pressed so as to be in close contact with the inner surface of the pipe 8. It is done. Further, the rear end side of the sealing skirt 60 is attached to the absorbing plate 21 by tightening with a belt or the like (not shown) so as to keep a watertight state with the absorbing plate 21.

  In the watertight space 13, the cooling gas 208 supplied from the cooling gas tube 44 is stored. By the function of a cooling gas supply device (not shown), the inside of the sealing skirt 60 is held so as to have a static pressure higher than the external water pressure, and the differential pressure inside and outside is discharged as exhaust gas 209. To eliminate water in the watertight space 13, an antioxidant gas supplied from the gas supply tube 7 may be used, and the antioxidant gas supply device 4 may have a pressure holding function in the watertight space 13.

  As in the first embodiment, the light shielding body 30 is configured by a light shielding wire 51 attached in a brush-like row so that an angle φ1 (see FIG. 4) formed with the surface of the absorption plate 21 is an acute angle. Has been. Further, the light shielding wire 51 is made of a rope obtained by twisting wire strands 53 (see FIG. 5), and the wire tip 52 is spherical.

  According to the fourth embodiment configured as described above, the light shield 30 absorbs the scattered light 206 such as irregular reflection due to the shape change of the work surface 10, the double reflected light 207 from the absorption plate 21, and the like. Thus, it is possible to prevent leakage to the outside, and thus it is possible to prevent equipment outside the laser irradiation head 1 from being damaged.

  In the fourth embodiment, the light shielding wire 51 is pressed so as to be in contact with the work surface 10, whereby the scattered light 206, the double reflected light 207, etc. can be shielded, and the scattered light 206 is applied to the sealing skirt 60. Irradiation with the double reflected light 207 or the like can be suppressed. Thereby, the soundness of the sealing skirt 60 can be maintained, and the air space in the watertight space 13 can be stably created. As a result, it is possible to stably perform clad welding even in the water in the water tank 11. In addition, in FIG. 12, the use state of the front end side from the nozzle 22 of 4th Embodiment is shown.

  Next, a modified example will be described with reference to FIGS. In these modified examples, linear grooves 48 or dotted grooves 49 are provided on the surface of the absorbing plate 21 in the first embodiment.

  In the modification shown in FIG. 13, a concentric linear groove 48 is formed by performing groove processing around the beam irradiation port 29 so that the grooves are concentric. In the example shown in FIG. 14, the radial linear groove 48 is formed by performing the radial groove processing around the beam irradiation port 29. The cross-sectional shape of these linear grooves 48 can be, for example, a semicircular shape as shown in FIG. 15, a triangular shape as shown in FIG.

  In the modification shown in FIG. 17, the dotted grooves 49 are formed on the entire surface of the absorbing plate 21. The shape of the dotted groove 49 can be, for example, a hemispherical shape as shown in FIG. 18 or a quadrangular pyramid shape as shown in FIG.

  When the linear groove 48 or the dotted groove 49 is formed on the surface of the absorption plate 21 as in the above modifications, the surface area of the absorption plate 21 can be increased and the amount of absorption of the reflected light 205 or the like is increased. Thus, the generation of the double reflected light 207 can be suppressed. As a result, it is possible to more reliably suppress damage to equipment outside the laser irradiation head 1.

  Further, in order to obtain the same effect, the surface area of the absorbing plate 21 can be increased by using the surface of the absorbing plate 21 as a textured surface having a large surface roughness. Furthermore, the surface of the absorbing plate 21 may be coated with a ceramic such as SiC (silicon carbide) or WC (tungsten carbide) having high infrared light absorption and high heat resistance by thermal spraying or the like.

Incidentally, in each of the above-described embodiments, the angle ψ1 formed by the beam irradiation axis 204 with respect to the construction normal axis 203 of the construction surface 10 shown in FIG. 2 is 0 by the ψ-axis driving device 104 shown in FIG. The posture of the laser irradiation head 1 can be adjusted so as to be in the range of not less than 90 ° and not more than 90 °. In this case, as shown in FIG. 20, the diameter of the laser irradiation spot is d, the diameter of the tip of the nozzle 22 is D, the distance between the absorption plate 21 and the work surface 10 is L, and the beam irradiation axis 204 to the absorption plate 21 When the distance to the outer periphery is W, ψ1 is preferably adjusted so as to satisfy the following two expressions.
2Ltan (ψ1) −d / 2> D / (2cos (ψ1)) (Formula 1)
2Ltan (ψ1) + d / 2 <W (Formula 2)

  For example, when using a condition in which the diameter d of the laser irradiation spot is reduced using the same optical system, the R-axis driving device 103 is adjusted to bring the laser irradiation head 1 closer to the work surface 10, so the distance L is reduced. At this time, the ratio that the reflected light 205 is irradiated to the nozzle 22 without being irradiated to the absorbing plate 21 is increased. In order to avoid this, the ψ-axis driving device 104 is adjusted to make ψ1 larger.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Laser irradiation head, 5 ... Optical fiber, 20 ... Lens tube, 21 ... Absorbing plate, 22 ... Nozzle, 25 ... Collimating lens, 26 ... Condensing lens, 30 ... Shading body.

Claims (15)

A laser light source for generating laser light;
A laser irradiation head for mounting a condensing lens for condensing the laser light, and irradiating the workpiece with the laser light;
Laser light transmission means for transmitting the laser light from the laser light source to the laser irradiation head;
An antioxidant gas supply device for supplying an antioxidant gas for preventing oxidation of the workpiece due to irradiation of the laser beam;
The laser irradiation head is interposed between the laser irradiation head and the workpiece, and is disposed in the laser irradiation head so as to surround the laser beam irradiation portion of the workpiece, and the laser irradiation head A laser processing apparatus, comprising: a light-shielding body made of any one of metal, ceramics, and carbon that can be deformed in accordance with a change in distance to the workpiece. The laser processing apparatus according to claim 1,
The laser processing apparatus, wherein the light shielding body is any one of a metal fiber, a ceramic fiber, and a carbon fiber. The laser processing apparatus according to claim 1 or 2,
An absorber for absorbing the laser light is disposed on a surface of the laser irradiation head facing the workpiece, and the light blocking body is disposed around the absorber. Laser processing equipment. The laser processing apparatus according to claim 3,
A laser processing apparatus, wherein a plurality of grooves are formed on a surface of the absorber facing the workpiece. It is a laser processing apparatus of any one of Claims 1-4,
The laser processing apparatus, wherein the laser beam transmission means is an optical fiber, and the laser irradiation head includes a collimator lens that makes the laser beam irradiated from the optical fiber parallel light. It is a laser processing apparatus of any one of Claims 1-5,
The laser processing apparatus, wherein the laser irradiation head is configured such that an optical axis of the laser beam on the surface of the workpiece is inclined with respect to a normal axis of the surface of the workpiece. It is a laser processing apparatus of any one of Claims 1-6,
The said light-shielding body is comprised from either the single wire wire which has a softness | flexibility, or the wire rope which twisted several strands. The laser processing apparatus characterized by the above-mentioned. The laser processing apparatus according to claim 7,
The laser processing apparatus, wherein the single wire or the wire rope formed by twisting a plurality of strands is made of metal. The laser processing apparatus according to claim 7 or 8,
The laser processing characterized in that the wire rope formed by twisting the single wire or the plurality of strands is disposed so as to be inclined with respect to the mounting surface of the laser irradiation head so that the tip is directed toward the center. apparatus. It is a laser processing apparatus of any one of Claims 7-9,
A laser processing apparatus, wherein a tip of a wire rope formed by twisting the single wire or the plurality of strands is a hemispherical curved surface. It is a laser processing apparatus of any one of Claims 1-6,
The light shielding body is composed of a plurality of columnar members disposed in the laser irradiation head,
A laser processing apparatus, wherein the columnar member is elastically movable in an axial direction according to a surface shape of the workpiece. The laser processing apparatus according to claim 11,
A laser processing apparatus, wherein a tip end portion of the cylindrical member is hemispherical It is a laser processing apparatus of any one of Claims 1-6,
The said light-shielding body is comprised from either a heat resistant fiber fabric or a heat resistant nonwoven fiber sheet. The laser processing apparatus characterized by the above-mentioned. It is a laser processing apparatus of any one of Claims 1-13,
A laser processing apparatus comprising: a cooling mechanism that cools the light shielding body by blowing a gas. It is a laser processing apparatus of any one of Claims 1-14,
A sealing skirt is provided between the laser irradiation head and the workpiece, and is disposed so as to surround the periphery of the light shielding body, and forms a space filled with gas inside. A featured laser processing apparatus.

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