JP3453280B2 - Laser processing head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing head used for laser welding, laser cutting, laser marking, etc., and in particular, a laser guided by a laser propagation means is changed by a reflecting mirror while being condensed by a condenser lens. The present invention relates to a laser processing head which is directed to form an image on a portion to be processed from a laser beam irradiation hole and performs predetermined laser processing.

[0002]

2. Description of the Related Art As an example of laser welding using a laser welding head, the situation of butt-circumferential welding of pipes is shown in FIG.
The laser welding head is shown in FIG. In FIG. 4, reference numerals 1 and 1 ′ are tubes to be welded, which are supported in a butt state by a structure (not shown). 2 is a butt welded portion of a pipe, 3 is a welder body, 4 is a fixed chuck integrated with the welder body 3, 5 is a handle of the fixed chuck 4, 6 is a drive motor, and 7 is rotated to the welder body 3. A horseshoe-shaped rotating body that is freely fixed, and is rotated along the pipe circumferential surface by a drive motor 6 via a power transmission mechanism incorporated in the welding machine main body 3. Reference numeral 8 is a welding control device, 9 is a laser welding head fixed to the horseshoe-shaped rotary member 7, and 10 is a connector attached to the end of the laser welding head.
It is connected to the laser oscillator 12 via 1. Explaining these actions, the welding machine main body 3 is fixed to the pipe 1 ′ by operating the handle 5 with the fixed chuck 4, and in this state, if the drive motor 6 is driven by the control device 8, the horseshoe-shaped rotating body is Since 7 rotates, the laser welding head 9 also rotates around the pipes 1, 1'to be welded.

Next, details of the laser welding head 9 are shown in FIG.
This will be described with reference to (A) and (B). FIG. 5A is a plan sectional view seen from above, and FIG. 5B is a side sectional view seen from a side surface. In FIGS. 5A and 5B, 1 and 1 ′ are pipes to be welded, 2 is a butt welded portion of the pipe, 10 is a connector, and 11 is an optical fiber, which has the same configuration as in FIG. 4. Thirteen
Is a mirror 15 'and a plurality of lens groups 27, 27', 2
7 ″ is housed in the outer cylinder, an end cylinder 17 that is integrated with the outer cylinder 13 is formed on the connector connection side, and an opening of the outer cylinder 13 located on the opposite side of the end cylinder 17 is formed into a discharge hole. It is sealed with an end plate 14 having 33. The mirror 15 'has a reflecting surface 15a obliquely cut downward on the side facing the lens groups 27, 27', 27 ".
Is held at a predetermined position by a mirror position adjusting screw 26 so as to face an opening window provided on the outer cylinder 13.
Further, an opening window portion 13a provided on the outer cylinder 13 is also attached with a protective glass 25 held by a holding plate 24, and the opening window portion 13a functions as a laser irradiation hole. In front of the mirror reflecting surface 15a, lens groups 27, 27 ', 27 "held by the lens holding barrel 16 are located.

Reference numeral 18 denotes a mirror cooling gas introduction hole provided in the end cylinder 17, the upstream side of which is connected to the mirror cooling gas supply pipe 21 and the downstream side between the outer circumference of the lens holding cylinder 16 and the inner circumference of the outer cylinder 13. The formed void 28 passes through the opening 28a, passes through the mirror storage space 31, and is discharged to the outside from the guide hole 33 of the end plate 14. Reference numeral 19 denotes a lens cooling gas introduction hole which is bored on the side opposite to the mirror cooling gas introduction hole 18 in the end cylinder 17, and which holds a lens through a gap 29 formed between the outer circumference of the lens holding cylinder 16 and the inner circumference of the outer cylinder 13. The hole 16a provided in the cylinder 16 passes through the lens surrounding space in the lens holding cylinder 16, and the hole 16b on the other side is used to ventilate the lens holding cylinder 16 to open the opening 2
It is configured such that it passes through the mirror storage space 31 via 8a and is discharged to the outside from the guide hole 33 of the end plate 14. The lower portion of the end cylinder 17 located on the side of the opening window 13a is widened downward and a spatter removal gas introduction hole 20 is bored along a direction parallel to the surface of the protective glass 25, and the introduction hole 20 is a spatter removal gas supply pipe. It is connected to 23. The dotted line 36 is a schematic line showing the path of the laser beam, 37 is the weld metal located on the butt-welded portion, and 38 is the spatter.

The operation of the prior art will be described below. The laser light guided by the optical fiber 11 is condensed by the lens groups 27, 27 ', 27 "through the connector 10 and the reflecting surface 15a of the mirror 15'. After being turned by, the welded pipe 1, through the protective glass 25 through the laser irradiation hole,
Focus on 1'weld 2 and melt it. In this state, if the welding head goes around the pipes 1 and 1'to be welded as described with reference to FIG. 4, the weld metal 37 is formed all around and the melting is completed.

However, in this case, heat and spatter are problems. In other words, since the transmittance of the lens and the reflectance of the mirror are not 100%, the amount of heat absorbed by the lens and the mirror increases as the laser intensity increases, and at the intensity level required for welding, it takes several minutes. If you don't, you will get damaged. In addition, when vapor of metal is generated from the molten metal and the molten metal is blown up to generate so-called spatter when the gas component is large, if these adhere to the surface of the protective glass 25, the transmittance sharply decreases and the protection is performed. Glass 25
Will be instantly damaged. For this reason, various measures are taken also in the laser welding head in the above-mentioned prior art, and by supplying the lens cooling gas from the lens cooling gas supply pipe 22 to the lens cooling gas introduction pipe 19, the outer circumference of the lens holding cylinder 16 and the outside thereof. Void 2 formed between the inner circumference of the cylinder 13
The lens 9 cools each lens when passing through the lens surrounding space in the lens holding cylinder 16 through the hole 16a provided in the lens holding cylinder 16. Further, the lens cooling gas is on the other side hole 16
After b is vented from the lens holding cylinder 16 through b, the mirror 15 ′ is cooled while passing through the mirror storage space 31 through the opening 28 a, it is discharged from the guide hole 33 of the end plate 14 to the outside.

Further, the cooling gas supplied from the mirror cooling gas supply pipe 21 to the mirror cooling gas introduction hole 18 has a gap 28.
After merging with the lens cooling gas after cooling the lens with, the mirror is cooled while passing through the mirror storage space 31 through the opening 28a, and then the guide hole 3 of the end plate 14 is provided.
3 is discharged to the outside. Further, for removing the spatter, the spatter removing gas supply pipe 23 is used to remove the spatter removing gas introduction hole 20.
The shield gas introduced in the above is trying to achieve the spatter removal by jetting in the direction crossing the surface of the protective glass 25.

[0008]

Therefore, in the above-mentioned conventional spatter removing method, the gas is jetted in parallel along the surface of the protective glass to blow out the spatter. However, this spouting gas 34 does not have a vector component for blocking the spatter 38 spouting from the weld metal 37 in the direction of the protective glass 25. It could not be removed, the protective glass 25 was damaged, and there was a problem that welding was frequently interrupted and repaired. Further, even if a neutral gas or an inert gas is used as the shield gas, when there is a high-speed flow as shown by the arrow 34, the air flow shown by the arrow 35 is formed in a form sucked by this,
Oxygen in the air flow oxidizes the weld metal, resulting in strength, appearance, and unsuitability as a welded joint.

On the other hand, the reflecting mirror 15 'shown in the above-mentioned prior art.
Had a mirror-finished end of a cylindrical metal rod (often made of copper) at 45 degrees to form a turning reflection surface 15a. However, this shape has a poor efficiency of heat transfer to the cooling gas and laser transmission. In order to avoid temperature rise due to heat absorption due to heat, it is necessary to have a dimensionally large heat capacity. For this reason, the laser welding head is unavoidably long, the length between the chucking portion and the welding portion of the welding machine is long, and the application location is sometimes restricted.

In view of the above technical problems, the present invention is to provide a laser processing head capable of efficiently preventing metal vapor or spatter generated from weld metal from adhering to protective glass. Another object of the present invention is to use an inert or neutral gas such as argon, helium, or nitrogen as the spatter-eliminating gas and the shielding gas in order to prevent the spatter from adhering to the protective glass, thereby welding. Another object of the present invention is to provide a laser processing head capable of preventing oxidation deterioration of a metal or other processed portion and obtaining a sound laser processing material. Furthermore, the present invention can achieve high heat transfer efficiency and sufficient cooling efficiency even when the reflection mirror is shortened and downsized, thereby eliminating troubles due to burnout of the mirror. It is to provide a laser processing head that can be downsized and the distance between the chucking position and the processing line (welding line) can be short, so that the range of application of laser welding is expanded.

[0011]

The invention according to claim 1 is
The laser guided by the laser propagating means is deflected by the reflection mirror while being condensed by the condenser lens, and is protected by the protective gas.
In a laser processing head that performs predetermined laser processing such as laser welding, laser cutting, and laser marking by forming an image on a processed portion from a laser light irradiation hole provided with a lath ,
On the surface side of the protective glass, the protective glass is used as a final diverting surface.
In addition to providing a curved gas flow path that also serves as a laser beam irradiation hole
The gas that has cooled the condenser lens or the reflection mirror is opened by opening the gas ejection hole, and the gas is recirculated through the bent gas flow path.
It is characterized in that it is ejected from the laser light irradiation hole toward the processed portion side. Further, in addition to the above configuration, the laser irradiation hole
Concentric ejection holes are provided around the
It is characterized by ejecting the gas after cooling the reflection mirror .

According to this invention, by forming a gas flow from the protective glass toward the weld metal, it is possible to prevent the spatter from flying to the protective glass, and further to concentrically shield gas around the laser irradiation hole. By injecting, the double gas shield prevents the inclusion of air and minimizes the oxidation of the processed metal (welded metal).

According to a third aspect of the present invention, the back side of the reflecting mirror is gradually tapered, and the back side is slightly smaller than the inner peripheral surface of the inner cylinder enclosing the reflecting mirror.
Provide cooling fins that are planted with a clearance , and use the fins to cool the reflecting mirror
Laser beam irradiation hole or its periphery through the curved gas flow path
It is possible to eject from the ejection hole provided in
And are characterized . More specifically, the back side of the mirror is formed into a polygonal pyramid or a cone, and a large number of needle-like or plate-like fins along the wind flow are attached to this surface.

For example, as shown in FIG. 2B, the cooling fins are radially arranged radially with a slight clearance with respect to the inner peripheral surface of the inner cylinder. Therefore, since the mirror side is formed in a tapered shape, as shown in FIGS. 1 (A) and 1 (B), as a result, the cooling fin becomes longer as it goes forward, and the heat exchange area of the cooling fin is correspondingly increased. It will spread significantly.

According to this invention, the rear side of the mirror is formed into a polygonal pyramid or a conical shape to widen the space for arranging the cooling fins so that more cooling fins can be planted. It is possible to obtain a laser welding machine with a wider range of application by increasing the heat transfer efficiency of the laser welding machine and consequently shortening the length of the laser welding head.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be exemplarily described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the constituent parts described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Only.

A laser welding head according to the first embodiment of the present invention is shown in FIGS. FIG. 1A is a plan view seen from above, showing the inside by removing the upper surface. FIG. 1 (B) is a front view seen from the front, with the front removed to show the inside. FIG. 1C is a side view seen from the right side. 2A is a plan view seen from the bottom, FIG. 2B is a cross-sectional view taken along the line aa in FIG. 2A, and FIG. 2C is a cross-sectional view taken along the line bb.
(D) shows a sectional view at the cc position. In FIGS. 1 and 2, the pipes 1 and 1 ′ to be welded, the welded portion 2, the connector 10, the optical fiber 11, the protective glass 25,
A plurality of lens groups 27, 27 ', 27 ", a weld metal 37,
The sputter 38 is the same as that described in the section of the prior art of FIGS. The present embodiment is not composed of only the outer cylinder 13 as in the prior art, but is composed of an inner cylinder 40 having a circular cross-section and a kamaboko-shaped outer cylinder 42. The lens groups 27, 27 ′ and 27 ″ of No. 1 are housed and the connector 10 is connected to the end surface on the lens incident side.
It is sealed with 4.

The mirror 15 has a reflecting surface 15a which is obliquely cut downward on the side facing the lens, and its rear side 1
50 is processed into a substantially conical taper shape, and has a large number of needle-shaped fins 151 that are planted on the outer peripheral surface of the cone along a direction orthogonal to the gas flow direction (axial direction). As shown in FIG. 2 (B), the needle-shaped fins 151 are radially arranged radially with a slight clearance with respect to the inner peripheral surface of the inner cylinder. Therefore, since the mirror back surface 150 on which the needle-shaped fins 151 are implanted is formed in a tapered shape,
As shown in FIGS. 1 (A) and 1 (B), as a result, the needle-shaped fin 1
51 becomes longer as it goes further, and the fin 15
The heat exchange area of 1 will be greatly expanded.

A bottom plate 41 is linearly arranged on the bottom surface of the inner cylinder 40, and an outer cylinder 42 is provided between the inner cylinder 40 and the bottom plate 41.
Confidentially envelops. Also, the outer cylinder 42 is such that the upper surface side is the inner cylinder 4.
The gas reservoir spaces 53 and 54 are formed on both the left and right sides of the same while being connected to the 0 top. 18 on the lower half side of the inner cylinder 40 located on the emitting surface side of the mirror reflecting surface 15a.
The 0 ° arc is cut, and the cut portion has a cylindrical inner tube 40 and a bottom plate 4 centered on the path of the laser light reflected by the mirror 15.
1 is provided with a partition wall 43 that is airtightly connected. Further, the bottom plate 41 is opened, and the protective glass 25 is placed in the opening.
Is attached and is held by a circular shield nozzle 45 located on the lower surface side.

As shown in FIG. 2A, the shield nozzle 45 has a circular shape having a diameter slightly smaller than the short width of the bottom plate 41,
As shown in FIG. 2 (C), a shield gas reservoir 46 processed into an annular groove shape is provided at a position facing the vent hole 41a provided on the outer side of the partition of the gas reservoir space 54 on the outer cylinder 42 side. A shield gas ejection hole 47, which is a row of annular holes formed in a ring shape from the bottom of the shield gas reservoir 46 toward the lower surface side of the nozzle 45, is provided. Partition wall 4
3 The bottom plate 41 located on the inner peripheral side has a U-shaped opening 51 on the side of the protective glass 25 mounting portion, and the opening 51
A circular spatter-excluding gas reservoir 48 is recessed in the shield nozzle 45 portion located on the bottom surface side of the bottom plate 41 of
1 by partially filling the sputter-excluded gas reservoir 48
A protective glass support piece 49 is provided in a radial direction at a position displaced by 20 °, and a sputter-excluded gas ejection hole 5 also serving as a laser beam irradiation hole is provided at the center of the sputter-excluded gas reservoir 48.
Open 0.

On the other hand, among the gas reservoir spaces 53, 54 formed on the left and right sides between the outer cylinder 42 and the inner cylinder 40, in one gas reservoir space 54, the mirror cooling gas supply pipe 2 is provided.
A mirror cooling gas introducing pipe 44 for guiding the mirror cooling gas of No. 1 near the end of the inner cylinder 40 is arranged, and the mirror cooling gas supplied from the introducing pipe 44 from the mirror cooling gas supply pipe 21 is shown in FIG. ), The gas is supplied into the inner cylinder 40 through the introduction tube opening 44a opened at the rear end of the mirror rear surface 150 at a tapered position, and the mirror rear surface 150 is deprived of heat through the needle fins 151 while the mirror 15 Reaching the front space,
Further, the mirror cooling gas is U around the protective glass 25.
It is configured such that it enters the sputter-excluded gas reservoir 48 through the character-shaped opening 51, passes through the surface of the protective glass 25 as the extruded gas, and is ejected from the sputter-excluded gas ejection hole 50 that functions as a laser irradiation hole.

On the other hand, the lens cooling gas supply pipe 22 is provided in the gas reservoir space 53 located on the opposite side of the gas reservoir space 54.
Of the lens group 27, 27 ′, 27 ″ are connected to the vent hole 40 a provided in the peripheral surface of the inner cylinder 40 to pass through the lens surrounding space in the lens inner cylinder 40 and further to the vent hole 40.
It is configured such that it is led out from b to the other side gas reservoir space 54.

The operation of this embodiment will be described below.
Since the laser beam propagation and focusing are the same as those in the conventional method described in FIG. 5, the description thereof will be omitted, and the flow states of the cooling gas, the sputter exclusion gas and the shield gas, which are the main parts of the present invention, will be described. The mirror cooling gas introduced into the conical surface 150 by the mirror cooling gas supply pipe 21, the mirror cooling gas introduction pipe 44, and the opening 44 a is guided to the vicinity of the tapered end of the mirror rear side 150 of the inner cylinder 40. The heat passes through between the fins 151 while absorbing heat, and reaches the space in front of the mirror 15.
Since this space is sealed by the inner cylinder 40, the partition wall 43, and the lens 27 ″, the mirror cooling gas passes through the U-shaped gap 51 around the protective glass 25 and the spatter-removed gas pool 48.
Then, while flowing along the surface of the protective glass 25 as spatter-exclusion gas, spatter is spouted from the sputter-exclusion gas spouting hole 50 in the central portion of the protection glass 25 while preventing the attachment of spatter.

On the other hand, the lens cooling gas supplied from the lens cooling gas supply pipe 22 to the gas storage space 53 between the outer cylinder 42 and the inner cylinder 40 is sealed in this gas storage space 53. As shown in (D), after cooling the lens through the ventilation hole 40a formed in the inner cylinder 40, the lens is discharged into the gas reservoir space 54 on the other side through the ventilation hole 40b formed in the other wall of the inner cylinder 40. To be done. Gas storage space 5
Since the bottom plate 41 outside the partition wall 43 is provided with the vent hole 41a, the lens cooling gas 4 passes through the vent hole 41a as shown in FIG.
And further ejected from a large number of shield gas ejection holes 47 arranged in a concentric ring shape on the outer peripheral side of the laser irradiation hole 50.

As described above, according to this embodiment,
Since the gas after cooling the mirror can be ejected at a high speed from the spatter exclusion gas ejection hole 50 while flowing as the spatter exclusion gas along the surface of the protective glass, the metal vapor and the spatter 38 generated from the weld metal 37, It is possible to efficiently prevent the glass from adhering to the protective glass 25 and prevent damage due to absorption of laser light. In addition, the gas for cooling the lens is finally arranged in a concentric circle around the laser beam emission hole 47 as a shield gas ejection hole 4
It is possible to prevent air from entering the welding atmosphere by ejecting the air from No. 7. Therefore, by using an inert or neutral gas such as argon, helium, or nitrogen as the spatter-eliminating gas and the shield gas, it is possible to prevent the oxidative deterioration of the weld metal and obtain a sound welded joint. Further, since the mirror used in this device has a structure in which a large number of needle-shaped fins 151 are implanted on the back surface to enhance the efficiency of heat transfer, it is sufficiently cooled even with a short length, and troubles due to mirror burnout are avoided. In addition to being eliminated, the laser welding head can be downsized and the distance between the chucking position and the welding line may be short, so that the range of application of laser welding is expanded.

Incidentally, as shown in FIG.
0 and the spattering exclusion gas ejection hole 501 may be provided independently of each other. That is, the bottom plate 41 on the inner peripheral side of the partition wall of the shield nozzle 45 has a U-shaped opening 51 on the side of the protective glass mounting portion, which is the same as in the previous embodiment, but the shield nozzle located on the bottom side of the opening 51. In FIG. 45, the spatter-exclusion gas reservoir 48 is recessed in a ring circle shape instead of the circular shape as in the above embodiment, and a large number of small-diameter sputter-exclusion gas ejection holes 50 are formed along the ring circle of the spatter exclusion gas reservoir 48.
1 is drilled. Then, a laser beam irradiation hole 500 is opened at the center of the protective glass 25.

According to such an embodiment, the mirror cooling gas enters the spatter exclusion gas reservoir 48 through the U-shaped gap 51 around the protective glass 25, and the spatter is formed in a ring shape on the outer peripheral side of the laser beam irradiation hole 500. Excluded gas ejection hole 50
A spatter-excluding gas is spouted from No. 1 to prevent the spatter from adhering to the surface of the protective glass 25 provided in the laser beam irradiation hole 500 by the ring-shaped air curtain. Also, the mirror cooling gas is supplied from the front side of the mirror to the rear side of the mirror.
It is also possible to circulate the 0 circumference surface to cool the mirror through the needle-shaped fins 151, and then to spout from the spatter exclusion gas (mirror cooling gas) spouting hole 501 provided on the outer circumference of the protective glass 25.

[0028]

As described above, according to the present invention as set forth in claim 1, it is possible to efficiently prevent metal vapor or spatter generated from the weld metal from adhering to the protective glass. Further, according to the present invention, in order to prevent the spatters and the like from adhering to the protective glass, even when an inert or neutral gas such as argon, helium, or nitrogen is used as the sputter exclusion gas and the shield gas, the air As a result, it is possible to prevent oxidative deterioration of the welded metal and other processed parts without involving the above, and to obtain a sound laser processed material. Further, according to the present invention as set forth in claim 2, even when the length and size of the reflection mirror are reduced, high heat transfer efficiency and sufficient cooling efficiency can be achieved, thereby eliminating troubles due to mirror burnout. In addition, the laser welding head can be downsized, and the distance between the chucking position and the processing line (welding line) may be short, so the range of application of laser welding has expanded.

[Brief description of drawings]

1 shows a laser welding head according to a first embodiment of the present invention, FIG. 1 (A) is a plan view seen from above, the upper surface is removed to show the inside, and FIG. 1 (B) is seen from the front. In the front view, the front surface is removed to show the inside, and FIG. 1C is a side view seen from the right side.

FIG. 2 shows a laser welding head according to the first embodiment of the present invention, FIG. 2 (A) is a plan view seen from the bottom surface, and FIG. 2 (B).
Is a cross-sectional view taken along the line aa in FIG. 2A, and FIG.
A sectional view at the position, and FIG. 2D shows a sectional view at the cc position.

FIG. 3 shows another embodiment of the present invention and is a correspondence diagram of FIG. 2 (C).

FIG. 4 is an illustration of butt circumferential laser welding of tubes as applied to the present invention and the prior art.

5A and 5B show details of a laser welding head according to a conventional technique, FIG. 5A is a plan sectional view seen from above, and FIG. 5B is a side sectional view seen from a side.

[Explanation of symbols]

Pipes to be welded 2 welds 3 Welder body 4 fixed chuck 5 handles 6 drive motor 7 Horseshoe-shaped rotating body 8 Welding control device 9 Laser welding head 10 connectors 11 Optical fiber 12 Laser oscillator 14 End plate 15 mirror 150 Rear of mirror 15 151 needle fins 16 lens holder 21 Mirror cooling gas supply pipe 22 Lens cooling gas supply pipe 25 protective glass 27, 27 ', 27 "multiple lens groups 36 Schematic line showing the path of laser light 37 Weld metal 38 Spatter 40 inner cylinder 41 Bottom plate 42 outer cylinder 43 partitions 44 Mirror cooling gas introduction pipe 45 shield nozzle 46 Shield gas reservoir 47 Shield gas ejection hole 48 Sputter-removed gas pool 49 Protective glass support piece 50 Spatter exclusion gas ejection hole 53, 54 Gas storage space

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-64-27789 (JP, A) JP-A-5-123884 (JP, A) JP-A-10-6063 (JP, A) Actual development Sho-57- 24742 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B23K 26/00-26/42

Claims (4)

(57) [Claims] 1. A laser beam guided by a laser beam propagating means is deflected by a reflection mirror while being condensed by a condenser lens so that an image is formed on a portion to be processed through a laser beam irradiation hole provided with a protective glass. In a laser processing head that performs predetermined laser processing such as laser welding, laser cutting, and laser marking, the protective glass is used as the final deflected surface on the protective glass surface side.
A curved gas flow path for
Opening the gas ejection holes on the outer peripheral, the gas after cooling the condenser lens or reflecting mirror, the curved gas flow path of the laser beam irradiation hole through or the
A laser processing head, characterized in that a laser beam is ejected from an ejection hole provided on the outer periphery toward a processed portion side. 2. A concentric circle centered on the laser irradiation hole.
-Shaped ejection holes to cool the condenser lens or the reflection mirror
The gas after being rejected is jetted out.
The laser processing head described. 3. A so as to form a tapering gradually back side of the reflecting mirror, this rear side, the reflecting mirror
With a slight clearance to the inner peripheral surface of the inner cylinder to be covered
Providing a cooling fin that is planted and reflecting by the fin
After cooling the mirror, the gas is passed through the bent gas channel.
From the laser beam irradiation hole or the ejection hole provided on the outer periphery of the hole.
The jetting is performed toward the processing portion side.
1. The laser processing head according to 1. 4. The cooling fins are slightly attached to the inner peripheral surface of the inner cylinder.
Radially planted with radial clearance
4. The laser processing head according to claim 3, wherein
De .