JP6150612B2 - Optical fiber transmission type laser processing apparatus, laser emitting unit, and optical fiber attaching / detaching method - Google Patents

Description

  The present invention relates to a technique for performing laser processing by condensing and irradiating a workpiece with laser light, and more particularly to an optical fiber transmission type laser processing apparatus, a laser emission unit, and a method for attaching and detaching an optical fiber in a laser emission unit.

  A laser processing apparatus basically includes a laser oscillator that oscillates and outputs a processing laser beam, a laser emitting unit that focuses and radiates the processing laser beam toward a workpiece, and a laser from the laser oscillator to the laser emitting unit. A laser transmission optical system for transmitting light. An optical fiber transmission system using an optical fiber in a laser transmission optical system can be flexibly adapted to various production lines and applications of laser processing because a laser oscillator and a laser emitting unit can be installed or arranged at arbitrary locations, respectively. There is an advantage.

  A laser emitting unit used in an optical fiber transmission system is provided with an optical fiber connector for detachably attaching an optical fiber terminal end to the upper surface or side surface of the unit main body, and a laser beam is received inside the unit main body. In addition to a condensing lens for condensing light at a processing point of a workpiece, a collimating lens for collimating laser light emitted from the end face of the optical fiber into parallel light is provided.

  Usually, the unit main body of the laser emission unit has a sealed structure in which the entrance and exit of the laser beam are closed. In other words, the optical fiber connector is coupled (fitted) to the end portion of the optical fiber or the plug holding the optical fiber without creating a gap. A protective glass is attached to the laser emission port of the unit body. For this reason, dust or dust does not enter the unit body from the outside through the optical fiber connector or the laser emission port.

JP 2007-30032 A

  In the optical fiber transmission system, as described above, while the transmission optical fiber is attached to the optical fiber connector of the laser emission unit, dust or dust does not enter the unit body from the outside. . However, for example, when the installation location of the laser emission unit is greatly changed in the factory, or when optical fiber replacement or maintenance is performed, the optical fiber may be temporarily removed from the optical fiber connector of the laser emission unit. At this time, dust or dirt enters the unit body from the outside through the fiber insertion port or plug insertion port of the optical fiber connector that is open or open, and enters the collimating lens located near the optical fiber connector. May adhere. If dust or dirt adheres to the collimating lens, it not only causes a decrease in laser output, but also causes the collimating lens to burn. This is a maintenance problem in conventional laser processing equipment or laser emitting units that employ an optical fiber transmission system. In terms of productivity, productivity and reliability.

  The present invention has been made in view of the above-described problems of the prior art, and in an optical fiber transmission system, dust or dirt is applied to a collimating lens for collimating laser light emitted from an end surface of an optical fiber into parallel rays. The present invention provides a laser processing apparatus, a laser emission unit, and an optical fiber attaching / detaching method that prevent adhesion of the toner and improve maintainability, productivity, and reliability.

  The laser emission unit according to the present invention is a laser emission unit that receives laser light for laser processing output from a laser oscillation unit via an optical fiber, and irradiates the laser light toward a workpiece. A unit main body having a laser emission port for emitting laser light, an optical fiber connector for detachably mounting the optical fiber, and collimating the laser light emitted from the end face of the optical fiber into parallel rays In order to do so, a collimating lens provided in the unit main body so as to face the end face of the optical fiber attached to the optical fiber connector via a sealable optical path space, and the collimated collimated to parallel light In order to focus the laser beam on the processing point on the workpiece, the unit faces the laser emission port. In order to inject a shielding gas into the optical path space in a direction intersecting the optical axis of the condensing lens provided in the main body and the collimating lens, the unit main body is disposed between the optical fiber connector and the collimating lens. A jet port provided in the wall or inside, and the optical fiber connector for discharging the shield gas jetted from the jet port into the optical path space to the outside of the unit body at a position facing the jet port. An openable and closable exhaust port provided in a wall portion of the unit main body with the collimating lens.

  The laser processing apparatus of the present invention transmits the laser beam oscillated and output from the laser oscillating unit to the laser radiating unit, a laser oscillating unit that oscillates and outputs laser light for laser processing, and the laser oscillating unit. And a shield gas supply unit for supplying a shield gas to the laser emitting unit.

  The optical fiber attaching / detaching method of the present invention is an optical fiber attaching / detaching method for attaching / detaching an optical fiber in the laser emitting unit, wherein the optical fiber is attached to the optical fiber connector, and the exhaust port is closed. Under the state of connecting the shield gas supply unit for sending the shield gas to the injection port, and starting the injection of the shield gas from the injection port to the optical path space; A step of opening the exhaust port after starting the ejection of the shield gas into the optical path space; and the ejection of the shield gas from the ejection port into the optical path space and the shield from the exhaust port to the outside of the unit body While continuing to discharge gas, the optical fiber is removed from the optical fiber connector, and then the same optical fiber is again and again. Newly another optical fiber, and a step of mounting the optical fiber connector, comprising the steps of closing the exhaust port, and a step of stopping the ejection of the shield gas to the optical path space from the injection port.

  In the present invention, while the exhaust port of the laser emitting unit is closed and the optical fiber is attached to the optical fiber connector, the unit body of the laser emitting unit is sealed, and the collimating lens as well as the condensing lens are used. Blocked from the outside atmosphere. Therefore, no dust or dust enters the unit body from the outside.

  In the laser emission unit, when the optical fiber is temporarily removed from the optical fiber connector, the exhaust port is opened, the shield gas from the shield gas supply unit is injected from the injection port, and the injected shield gas is collimated. By crossing the optical path space in front of the lens and exiting from the exhaust port, an air curtain of shield gas is formed in front of the collimating lens when viewed from the optical fiber connector side. As a result, even if the collimating lens is exposed to the outside atmosphere through the optical fiber insertion port (or plug insertion port) of the optical fiber connector, the dust and dirt from the outside are blocked by the shield gas air curtain and the collimating lens. It will not adhere to. Therefore, the output of the laser beam does not decrease or the collimating lens is not burned due to dust or dirt adhering to the collimating lens.

  According to the laser processing apparatus, the laser emitting unit or the optical fiber attaching / detaching method of the present invention, the laser beam emitted from the end face of the optical fiber in the optical fiber transmission system is collimated into parallel rays by the above-described configuration and operation. It is possible to prevent dust and dirt from adhering to the collimating lens, and improve maintainability, productivity and reliability.

1 is a diagram showing an overall configuration of an optical fiber transmission type laser processing apparatus according to an embodiment of the present invention. It is a partial cross section top view which shows the structure of the laser emission unit in the said laser processing apparatus. It is a partial expanded sectional view which shows the structure (state with which the optical fiber is mounted | worn) of the principal part of the said laser emission unit. It is sectional drawing which follows the AA line of FIG. It is a partial expanded sectional view which shows the structure (state where the optical fiber is removed) of the principal part of the said laser emission unit. It is sectional drawing which follows the AA line of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
[Configuration of the entire laser processing apparatus]

  FIG. 1 shows an overall configuration of an optical fiber transmission type laser processing apparatus according to an embodiment of the present invention.

  The laser processing apparatus includes a laser oscillator 10, a laser power source 12, an optical fiber transmission system 14, a laser emission unit 16, a shield gas supply unit 18, a main control unit 20, a touch panel 22, and a processing table 24.

  The laser oscillator 10 is, for example, a single mode fiber laser oscillator, and includes an oscillation optical fiber having a core doped with, for example, rare earth element ions as a light emitting element, and pumping light for pumping on one end face of the oscillation optical fiber. And a pair of optical resonator mirrors that resonately amplify and output light of a predetermined wavelength that is emitted in the axial direction from both ends of the oscillation optical fiber, for example, a high output of 500 W or more And oscillates and outputs a continuous-wave laser beam or a pulsed laser beam LB having a high condensing property.

  The laser power source 12 supplies an excitation current to a light source (generally a laser diode) of an electro-optical excitation unit of the laser oscillator 10 under the control of the main control unit 20. Although not shown, it is possible to provide a power feedback mechanism for controlling the excitation current by feeding back the power of the laser beam LB output from the laser oscillator 10 to the laser power source 12.

  The laser beam LB output from the laser oscillator 10 is folded in a predetermined direction by, for example, a vent mirror 30 in the optical fiber transmission system 14, and then condensed by the condenser lens 34 in the incident unit 32, and transmitted. Incident on one end face of 36. The transmission optical fiber 36 is made of, for example, an SI (step index) type fiber, and transmits the laser beam LB input to one end surface of the incident unit 32 to the laser emitting unit 16.

  The laser emitting unit 16 has a unit main body 46 that houses or equips an optical system such as a collimating lens 40, a galvano scanner 42, and a condenser lens 44, and a terminal portion of the optical fiber 36 on one side surface of the unit main body 46. An optical fiber connector (for example, a receptacle) 48 for detachably mounting is provided. Further, the laser emission unit 16 can be connected to the shield gas supply unit 18 via the gas supply pipe 50.

  In the laser emitting unit 16, the laser light LB emitted from the end face of the optical fiber 36 with a constant divergence angle is collimated into parallel rays by the collimating lens 40, and a beam spot is formed on the processing point on the workpiece W by the galvano scanner 42. Are scanned in a two-dimensional direction (XY direction) so as to be converged by a condenser lens 44 so as to be condensed at a processing point. At that time, the scanner control unit 25 controls the scanning operation of the galvano scanner 42 under the control of the main control unit 20. In this laser processing apparatus, for example, when laser welding is performed, the base material is melted by the energy of the laser beam LB at the processing point on the workpiece W to which the laser beam LB is focused and irradiated, and the laser beam LB The nugget is formed by solidification after the irradiation.

  The processing table 24 supports the workpiece W so as to face the laser emission port 47 of the laser emission unit 16. The processing table 24 may be provided with a moving mechanism (not shown) for moving or positioning the workpiece W in the horizontal (XY) direction, the rotation (θ) direction, and / or the vertical (Z) direction. .

The main control unit 20 includes a CPU (microcomputer), controls the operation of the entire apparatus or each unit according to various programs (software) stored in the program memory, and inputs the input unit 22a and the display unit 22b of the touch panel 22. And exchanges information (setting values, monitor information, etc.) with users (operators, maintenance personnel, etc.).

[Configuration of laser emission unit]

  In FIG. 2, the structure of the principal part of the laser emission unit 16 is shown. As shown in the figure, the laser emitting unit 16 includes three subunits, that is, a collimating unit 52 that houses the collimating lens 40, a dichroic unit 54 that houses the dichroic mirror 55, and a galvano unit 56 that houses the galvano scanner 42. The optical fiber connector 48 is attached to the tip (left end in the figure) of the collimator unit 52.

  Of these three subunits 52, 54, 56, the feature in this embodiment is a collimating unit 52. The dichroic unit 54 and the galvano unit 56 are the same as those conventionally known. As shown in FIG. 1, the condenser lens 44 is disposed at the bottom of the galvano unit 56 so as to face the laser emission port 47. A protective glass (not shown) is attached to the laser emission port 47.

Referring again to FIG. 2, a CCD camera 58 is attached to the dichroic unit 54 on the side opposite to the galvano unit 56. In the dichroic unit 54, the laser beam LB from the collimating unit 52 is incident on the dichroic mirror 55, where it is reflected at a right angle toward the galvano unit 56 side. Further, the visible light VR that has propagated in the opposite direction from the workpiece W through the optical system (the condenser lens 44 and the galvano scanner 42) in the galvano unit 56 and has entered the dichroic unit 54 passes straight through the dichroic mirror 55. The light enters the CCD camera 58 through a condenser lens (not shown).

[Configuration of collimator unit]

  Hereinafter, the configuration of the collimator unit 52 will be described in detail with reference to FIGS.

  As shown in FIGS. 2, 3, and 5, the collimating unit 52 includes a cylindrical casing (housing member) 60 coupled to the dichroic unit 54 and a cylindrical shape that holds the collimating lens 40 inside the casing 60. Lens holder 62. The lens holder 62 holds the collimating lens 40 at its tip (left end in the figure), and adjusts the distance between the end surface of the optical fiber 36 attached to the optical fiber connector 48 and the collimating lens 40 (normally). Is slidable in the optical axis direction (X direction) to match the focal length of the collimating lens 40, and is fixed to the casing 60 with a set screw 64 at an arbitrary position within the movable range. Yes.

  At the front end of the casing 60, for example, a ring-shaped throttle for blocking reflected light from the workpiece W side in front of the optical fiber 36 on the radially inner side via a mounting bolt (not shown). 66 is coupled, and a cylindrical receptacle or optical fiber connector 48 is coupled axially outward via a ring-shaped or cylindrical cooling jacket 68. In the illustrated configuration example, a sleeve-type plug 70 is attached to the end portion of the optical fiber 36, and the plug 70 is detachably attached to the optical fiber connector 48.

  When the plug 70 is attached to the optical fiber connector 48, an optical path space that can be sealed and opened between the front end portion of the plug 70 (or the end portion of the optical fiber 36) and the collimating lens 40 in the casing 60. PS is formed.

  An injection port 72 for injecting a dust-proof shield gas SG toward the optical path space PS between the diaphragm 66 and the collimating lens 40 in the optical axis direction (X direction) on the wall portion of the casing 60; An openable / closable exhaust port 74 for discharging the shield gas SG injected from the injection port 72 into the optical path space PS to the outside of the casing 60 is formed. The ejection port 72 and the exhaust port 74 are opposed to each other with the optical path space PS interposed therebetween. In the illustrated configuration example, the injection port 72 has a form of a through hole, and the exhaust port 74 has a form of a slit or a notch.

  As shown in FIG. 4, the injection ports 72 extend or distribute on an arc having a central angle α of preferably 60 ° to 120 ° (about 90 ° in the illustrated example) in the circumferential direction of the casing 60. , Preferably in a line in a plane orthogonal to the optical axis of the collimating lens 40, that is, a plurality of gas injection directions aligned in one direction (Y direction) and in a line orthogonal to it (Z direction) (5 in the illustrated example) are provided. Thereby, when the shielding gas SG is ejected from each ejection port 72, the ejected shielding gas SG crosses the optical path space PS so as to cover the whole along the incident surface of the collimating lens 40, and the exhaust port directly opposite. It flows to the 74 side (refer to FIG. 6).

  On the outer peripheral surface of the casing 60, a manifold groove 76 for sending the shield gas SG supplied from the shield gas supply unit 18 from the back to the injection port 72 is formed. The groove 76 has a function of making the injection pressure of each injection port 72 uniform and increasing the air supply conductance. A fixed cover 78 having a semicircular cross section that covers and seals the groove 76 is fixed to the casing 60 and a gas inlet 80 connected to the gas pipe 50 is provided in the fixed cover 78. A packing 82 is attached to the peripheral edge of the groove 76.

  On the other hand, the exhaust port 74 is located directly opposite to the injection port 72 and extends on an arc having a central angle β of preferably 90 ° to 150 ° (about 120 ° in the illustrated example) in the circumferential direction of the casing 60. It is distributed and preferably has an opening area larger than that of the injection port 72. Behind the exhaust port 74, a groove portion 84 in which a packing 86 is mounted is formed on the outer peripheral surface of the casing 60. A movable cover 88 having a semicircular cross section that is rotatably attached to the casing 60 via a hinge 90 covers the exhaust port 74 and the groove portion 84 so as to be hermetically sealed. The casing 60 is provided with a fastener 92 for holding a movable cover 88 that closes the exhaust port 74 and the groove 84 on the opposite side of the hinge 90.

  A water cooling pipe 94 is attached to the cooling jacket 68 (FIGS. 2, 3, and 5). For example, the casing 60, the lens holder 62, the fixed cover 78, the movable cover 88, and the cooling jacket 68 are made of metal having excellent workability or thermal conductivity, such as aluminum, and the diaphragm 66 is reflected light. For example, copper having excellent reflectivity with respect to copper is used. For the water-cooled pipe 94, a metal excellent in rust prevention, such as stainless steel, is used.

The shield gas supply unit 18 may be an arbitrary gas supply source that sends the shield gas at a constant pressure, and may be either an automatic type or a manual type. In the case of the automatic type, for example, a gas supply device including a gas container, a pump or compressor, a filter, an on-off valve, or the like is preferably used. In the case of the manual type, for example, an air spray gun, an air spray can or the like is preferably used. The shield gas may be any gas that does not cause the alteration or contamination of the collimating lens 40, and usually clean air or nitrogen gas is suitably used.

[Method of attaching / detaching optical fiber and action of collimating unit]

  Next, the method of attaching / detaching the optical fiber 36 and the operation of the collimating unit 52 in the laser emission unit 16 of this embodiment will be described.

  When the optical fiber 36 is attached to the optical fiber connector 48 of the laser emitting unit 16, the movable cover 88 of the collimator unit 52 is locked to the fastener 92, and the exhaust port 74 and the groove 84 are closed (see FIG. 3, FIG. 4). In addition, the shield gas supply unit 18 stops sending the shield gas SG, or is shielded or separated from the gas inlet 80 of the collimator unit 52.

  In this state, not only the dichroic unit 54 and the galvano unit 56 of the laser emission unit 16 but also the collimator unit 52 is sealed, and the optical system (the optical fiber 36, the collimator lens 40, the dichroic mirror 55, the galvano mirror) in the laser emission unit 16 is sealed. The scanner 42 and the condenser lens 44) are all shielded from the outside atmosphere. Therefore, dust and dirt do not enter the laser emitting unit 16 from the outside, and dust and dirt do not adhere to the internal optical system.

  However, for example, when the installation location of the laser emission unit 16 is greatly changed in the factory, or when the optical fiber 36 is replaced or maintained, the optical fiber 36 is temporarily removed from the optical fiber connector 48 of the laser emission unit 16. Sometimes.

  In this embodiment, before removing the optical fiber 36 from the optical fiber connector 48, an operator connects the shield gas supply unit 18 to the gas inlet 80 of the collimator unit 52 or confirms the connection state thereof. Supply of the shield gas SG from the shield gas supply unit 18 into the collimator unit 52 is started. At this time, since the movable cover 88 is still closed, the shield gas SG injected from the injection port 72 in the collimator unit 52 fills the optical path space PS. In this case, the supply flow rate of the shield gas SG may be controlled slightly. Then, after the optical path space PS is brought into an appropriate positive pressure or positive pressure state by the shield gas SG, the movable cover 88 is removed from the fastener 92 and the movable cover 88 is opened. Then, the exhaust port 74 and the groove portion 84 are opened or opened.

  Thus, the shield gas SG injected from the injection port 72 crosses the optical path space PS so as to cover the entire incident surface of the collimator lens 40 and flows out from the exhaust port 74 directly opposite. Thus, an air curtain of the shielding gas SG is formed in the optical path space PS so as to cover the incident surface of the collimating lens 40. At this time, since the pressure of the shield gas SG acts on the exhaust port 74 outward from the optical path space PS, dust or dust does not enter the optical path space PS through the exhaust port 74 from the outside.

  In this state, the worker removes the optical fiber 36 from the optical fiber connector 48. Then, the plug insertion port of the optical fiber connector 48 is opened or opened, and the collimating lens 40 is exposed to the outside atmosphere through the opened plug insertion port (FIGS. 5 and 6). However, even at this time, since the air curtain of the shielding gas SG is formed in front of the collimating lens 40, even if dust or dirt enters from the outside through the plug insertion port of the optical fiber connector 48, the shielding is performed. It is pushed back by the gas SG or driven out of the exhaust port 74 so as to be caught in the shield gas SG. For this reason, no dust or dirt adheres to the collimating lens 40.

  As described above, while the optical fiber 36 is not attached to the optical fiber connector 48, the shield gas SG is injected from the injection port 72 to the optical path space PS and the shield gas from the exhaust port 74 to the outside of the unit in the collimator unit 52. The discharge of SG is continued, and the air curtain of the shield gas SG is continuously formed in front of the collimating lens 40.

  Therefore, no matter what the purpose of removing the optical fiber 36 from the optical fiber connector 48 is, the time required for the work (transfer of the laser emitting unit 16 or repair, cleaning, replacement, etc. of the optical fiber 36) is short. Even if it is long, no dust or dirt adheres to the collimating lens 40.

  Then, after the end of the work, the end portion of the same optical fiber 36 as before or the end portion of another replaced optical fiber 36 is attached to the optical fiber connector 48 via the plug 70. At that time, when the plug 70 is inserted into the plug insertion port of the optical fiber connector 48, the air staying in the plug insertion port is pushed into the inner space of the optical path space PS, but the collimating lens is formed by the air curtain of the shielding gas SG. It is shielded from 40 and discharged immediately through the exhaust port 74. Therefore, even if dust or dust is mixed in such staying air, the dust is not attached to the collimating lens 40 and is discharged to the outside from the exhaust port 74.

  In this way, after the optical fiber 36 is reattached or newly attached to the optical fiber connector 48, the movable cover 88 is returned to a position covering the exhaust port 74 and the groove portion 84 and locked to the fastener 92. Also, the shield gas supply unit 18 stops sending the shield gas SG. When the shield gas supply unit 18 is a manual type air spray, after the air spray is stopped and removed from the gas introduction port 80, the gas introduction port 80 is closed with a stopper or a cap (not shown).

As described above, in this embodiment, the collimating lens 40 accommodated in the laser emitting unit 16 (collimating unit 52) when the optical fiber 36 is attached to or detached from the laser emitting unit 16 (particularly the collimating unit 52). Even if exposed to the outside atmosphere through the plug insertion port of the optical fiber connector 48, there is no possibility that dust or dirt will adhere to the collimating lens 40. Therefore, the output of the laser beam LB does not decrease or the collimating lens 40 is not burned due to dust or dirt adhering to the collimating lens 40. As a result, the laser processing apparatus or the laser emission unit in this embodiment can improve maintainability, productivity, and reliability.

[Other Embodiments or Modifications]

  The preferred embodiment has been described above, but the structure, shape, dimensions, material, operation, function, application, work procedure, and the like in the embodiment are described as preferred examples, and these are described in the claims. It is not intended to limit the scope of the invention.

  For example, in the above embodiment, a plurality of (or one) through holes are formed in the wall portion of the casing 60 and the exhaust port 74 is formed as a notch or a slit. However, a configuration in which the injection port 72 is formed by slitting, or a configuration in which the exhaust port 74 is formed as one or a plurality of through holes is also possible.

  In the above embodiment, the terminal portion of the optical fiber 36 is attached to the optical fiber connector 48 via the plug 70. However, a configuration in which the end portion of the optical fiber 36 is detachably attached to the optical fiber connector without using a plug is also possible, and the optical fiber connector can take various types or configurations.

  A configuration in which the galvano scanner 42 and the CCD camera 58 are not provided in the laser emission unit 16 is also possible, and conversely, another optical system may be added to the laser emission unit 16. The laser oscillator 10 is not limited to a fiber laser oscillator, and may be a YAG laser oscillator, for example.

  The laser processing apparatus of the present invention is not limited to welding, and can be used for arbitrary laser processing such as drilling, cutting, marking, and trimming.

DESCRIPTION OF SYMBOLS 10 Laser oscillator 12 Laser power supply 14 Optical fiber transmission system 16 Laser emission unit 18 Shield gas supply part 20 Main control part 40 Collimating lens 44 Condensing lens 46 Unit main body 48 Optical fiber connector 52 Collimating unit 60 Casing 62 Lens holder 72 Injection port 74 Exhaust port 78 Fixed cover 80 Gas inlet port 88 Movable cover

Claims (11)

A laser emitting unit that receives laser light for laser processing output from a laser oscillation unit via an optical fiber, and irradiates the laser light toward a workpiece,
A unit main body having a laser emission port for emitting the laser light, and an optical fiber connector for detachably mounting the optical fiber;
In order to collimate the laser light emitted from the end face of the optical fiber into parallel rays, the unit faces the end face of the optical fiber attached to the optical fiber connector via a sealable optical path space. A collimating lens provided in the main body,
A condensing lens provided in the unit main body facing the laser emission port in order to condense the laser beam collimated into parallel rays onto a processing point on the workpiece;
In order to inject shielding gas into the optical path space in a direction intersecting the optical axis of the collimating lens, an injection port provided in the wall portion or inside of the unit body between the optical fiber connector and the collimating lens,
In order to discharge the shield gas injected into the optical path space from the injection port to the outside of the unit main body at a position facing the injection port, between the optical fiber connector and the collimating lens, A laser emitting unit having an openable / closable exhaust port provided on a wall.   2. The laser emitting unit according to claim 1, wherein the ejection port is formed in a cylindrical housing member that constitutes a part of the unit main body on a radially outer side of a cylindrical lens holder that holds the collimating lens.   The laser emitting unit according to claim 2, wherein a plurality of the injection ports are provided in a line within a plane orthogonal to the optical axis of the collimating lens.   4. The laser emitting unit according to claim 2, wherein the injection port extends or distributes on an arc having a central angle of 60 ° to 120 ° in a circumferential direction of the housing member. 5. A manifold groove formed on the outer peripheral surface of the housing member for sending the shield gas supplied from an external shield gas supply unit to the injection port;
A first cover fixedly attached to the outer peripheral surface of the housing member so as to cover and cover the groove portion;
The laser emitting unit according to any one of claims 2 to 4, further comprising: a gas inlet provided in the first cover for introducing the shield gas from the shield gas supply unit into the groove. The laser emission unit according to any one of claims 2 to 5, wherein the exhaust port extends or is distributed on an arc having a central angle of 90 ° to 150 ° in a circumferential direction of the housing member.   The laser emitting unit according to claim 6, further comprising a movable second cover that is pivotally attached to an outer peripheral surface of the housing member via a hinge in order to open and close the exhaust port. The laser emission unit according to any one of claims 1 to 7, wherein the exhaust port has an opening area larger than that of the ejection port.   The laser emission unit according to any one of claims 1 to 8, wherein the shield gas injected from the injection port traverses the optical path space along an incident surface of the collimator lens. The laser emission unit according to any one of claims 1 to 9,
A laser oscillation unit that oscillates and outputs laser light for laser processing;
An optical fiber for transmitting the laser beam oscillated and output from the laser oscillation unit to the laser emitting unit;
A laser processing apparatus, comprising: a shield gas supply unit that supplies a shield gas to the laser emitting unit. An optical fiber attaching / detaching method for attaching / detaching an optical fiber in the laser emitting unit according to claim 1,
Under a state where the optical fiber is attached to the optical fiber connector and the exhaust port is closed, a shield gas supply unit for sending the shield gas is connected to the injection port, and Starting the injection of the shielding gas into the optical path space;
Opening the exhaust port after starting the injection of the shielding gas from the injection port to the optical path space;
The optical fiber is removed from the optical fiber connector while continuing the injection of the shield gas from the injection port to the optical path space and the discharge of the shield gas from the exhaust port to the outside of the unit body, and thereafter Attaching the same optical fiber again or another optical fiber to the optical fiber connector;
Closing the exhaust port;
A step of stopping injection of the shield gas from the injection port into the optical path space.

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