JP2810625B2 - Laser processing head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to a laser processing head for processing a workpiece such as iron, stainless steel, and aluminum by, for example, cutting.

[0002]

2. Description of the Related Art A typical prior art is shown in FIG.
And the bottom surface is simplified and shown in FIG. A laser beam 2 is guided into a head 1 through a condenser lens 3, irradiated onto a workpiece 6 made of a metal material through a nozzle hole 5 of a nozzle 4, and melted and cut as indicated by reference numeral 7. You. The head 1 is supplied with an assist gas from the connection port 8 and is jetted from the nozzle hole 5 toward the workpiece 6. The bottom surface of the nozzle 4 is as shown in FIG. 12, and from the nozzle hole 5, the converged laser light is irradiated onto the workpiece 6 as described above, and the assist gas is jetted.

[0003] The assist gas from the nozzle hole 5 serves to blow off the molten metal by the laser beam of the workpiece 6 and to protect the lens 3 by preventing the lens 3 from being stained during this cutting.

When the workpiece 6 is an iron-based material such as mild steel, oxygen is used as an assist gas, thereby making it possible to reduce the output of a laser beam by utilizing heat of oxidation reaction of iron. In addition, even with the same output, a workpiece as thick as possible can be cut.

If the flow rate of oxygen is increased to cut the thick workpiece 6, the oxidation reaction is promoted more than necessary,
The work material 6 itself burns excessively, so-called self-
A phenomenon called burning occurs, which reduces the accuracy of the cut surface. Therefore, there is a limit to increasing the flow rate of oxygen as the assist gas.

Another prior art which solves such a problem and can improve the accuracy of the cut surface is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-130791. In this prior art, a nozzle hole through which a laser beam passes and a plurality of annular nozzle holes concentrically surrounding the nozzle hole are formed to form a multi-ring structure, and cutting processing is performed by injecting an assist gas from these nozzle holes. I do.

[0007]

In such prior art, the assist gas ejected from the central nozzle on the axis of the head is protected by being surrounded by the assist gas ejected from other concentric nozzles. Although the purity of the assist gas from the central nozzle hole is maintained, the cross-sectional shape of the processing point is effectively maintained, and precise processing is possible, but some measures have been taken to cut thicker workpieces. According to the experiments of the present inventor, when the workpiece is made of mild steel, the cuttable plate thickness is at most 22 to 25 mm.

[0008] An object of the present invention is to provide a laser processing head capable of setting a gas injection area accurately and further increasing the thickness of a workpiece to be cut. .

In the prior art, dross, which is a metal oxide, adheres and remains fixed downstream of the assist gas in the direction of injection of the assist gas during processing of a workpiece made of a metal material. Therefore, after machining such as cutting, an operator must use a working tool such as a grinder to grind and remove the dross, which is troublesome.

Therefore, another object of the present invention is to provide a laser processing head capable of facilitating processing operations such as cutting.

[0011]

According to the present invention, there is provided a head body having an optical path for guiding a laser beam and irradiating a workpiece with laser light from a first nozzle hole; A cover member forming a second nozzle hole surrounding the first nozzle hole, the cover member having a common axis with the nozzle hole, and forming a second nozzle hole surrounding the first nozzle hole; And a second gas is supplied to a space between the outer peripheral surface of the head main body and the inner peripheral surface of the cover member, wherein the head main body includes a first nozzle member having a first nozzle hole,
A mounting cylinder body to which a first nozzle member is removably mounted to form an outward flange, a first cap nut for locking the outward flange of the mounting cylinder body, and a first cap nut are screwed. An adjusting cylinder, and a holding cylinder on which the adjusting cylinder is mounted and in which the lens is accommodated. The outer peripheral surface of the holding cylinder has an inner peripheral surface inside the accommodating hole of the retaining cylinder. A large-diameter cylindrical portion that fits along, a holding portion that forms a room radially inward from the inner circumferential surface of the storage hole of the holding cylindrical body, and a portion that extends below the holding portion and extends from the inner circumferential surface of the holding portion. A holding ring having a receiving portion projecting inward in the radial direction is also accommodated, and the receiving portion of the holding ring is made of a soft synthetic resin having an injection hole opened toward the lens and formed to communicate with the room. A first lens press ring is supported, and a lens is mounted on the first lens press ring. A second lens press ring made of a soft synthetic resin is placed on the periphery of the lens, and a spring is placed on the second lens press ring, and the spring is screwed onto the holding ring from above the spring. Pressed by a spring holding member to be worn,
A first connection port communicating with the room is formed in the holding cylinder, and a first gas is supplied from the first gas supply source to the first connection port. .

Further, the present invention is characterized in that a cooling water passage for supplying cooling water is formed at the bottom of the mounting cylinder.

Further, a cooling water passage through which cooling water is supplied is formed at the bottom of the holding cylinder of the present invention.

According to the present invention, the head body includes a first
A first nozzle member having a nozzle hole, a mounting cylinder body to which the first nozzle member is detachably mounted to form an outward flange, and a first cap nut engaged with the outward flange of the mounting cylinder body And an adjustment cylinder to which the first cap nut is screwed, and a holding cylinder to which the adjustment cylinder is attached and in which the lens is housed. Therefore, by loosening the first cap nut, the mounting cylinder and the first nozzle member together with the first cap nut can be removed from the adjusting cylinder. In addition, since the first cap nut is screwed to the adjusting cylinder, the height of the first nozzle member can be adjusted according to the tightening position of the first cap nut. Thus, the distance between the first and second nozzles and the workpiece is adjusted so that the focal point of the laser beam on the workpiece coincides, or the injection region of the first and second gases is set accurately. So that it can be set optimally.

A holding wheel is housed in the holding hole of the holding cylinder. The retaining ring has a large-diameter portion whose outer peripheral surface fits along the inner surface of the storage hole of the holding cylinder, and a holding portion that forms a room radially inward from the inner peripheral surface of the storage hole of the holding cylinder. , And a receiving portion that extends below the holding portion and protrudes radially inward from the inner peripheral surface of the holding portion. A receiving portion of such a holding ring supports a first lens press ring, a lens is mounted on the first lens press ring, and a second lens press ring is provided on the periphery of the lens. Placed, and the second lens holding ring is
It is held down by a spring holding member screwed to the holding wheel.
The first and second lens retaining rings are made of a soft synthetic resin, and the spring is maintained between the first and second lens retaining rings by the spring. A first gas is supplied from a first gas supply source to a first connection port formed in the holding cylinder, and the first gas is injected from the injection hole toward the lens through the chamber. The lens is cooled by the first gas injected from such an injection hole, and the injected first gas is supplied into a space below the lens, and is covered from the first nozzle hole of the first nozzle member. It is sprayed on the processed material to prevent dross from adhering. In this way, the first gas can simultaneously achieve the two functions of cooling the lens and removing dross.

Further, according to the present invention, a cooling water passage is formed at the bottom of the mounting cylinder, and cooling water is supplied to the cooling water passage, so that the mounting cylinder and the first nozzle member are cooled. Can be.

Further, according to the present invention, a cooling water passage is formed at the bottom of the holding cylinder, and the cooling water is supplied to the cooling water passage. It is possible to suppress a rise in temperature due to heat generation during transmission of laser light.

[0018]

FIG. 1 is a sectional view of a nozzle tip 10 which constitutes a part of a laser processing head for cutting a workpiece made of a metal material using a laser beam, and FIG. FIG. 10 is a bottom view of FIG. The nozzle tip 10 constitutes a part of the laser processing head 11 shown in FIG. The nozzle tip 10 basically includes a nozzle member 12 and a cover member 13 surrounding the nozzle member. The nozzle member 12 forms a part of the head body 14. The head body 14 has a mounting cylinder 15 to which the nozzle member 12 is detachably mounted, and a bag which is engaged with an outward flange 16 formed on the mounting cylinder 15 and is screwed to an external thread of the adjustment cylinder 17. A nut 18, lock nuts 19, 20, and a holding cylinder 22 to which the adjusting cylinder 17 is attached by a retaining ring 85 fixed by bolts 21. 24. This substrate 24
Is detachably attached to a flange 27 of an attachment member 26 such as an XY table or a wrist of an industrial robot by a bolt 25.

FIG. 4 is a horizontal sectional view of the mounting cylinder 15 of the head body 14 in FIG. At the bottom 28 of the mounting cylinder 15, an internal screw 2
9, an external screw 30 formed at the upper end of the nozzle member 12 is detachably screwed thereto. A cooling water passage 31 is formed in the bottom 28 as shown in FIG.
The cooling water supplied from the connection port 32 is discharged from the other connection port 33, and the bottom 28 is cooled, so that the nozzle chip 10 including the nozzle member 12 and the cover member 13 is cooled.

FIG. 5 is a horizontal cross-sectional view of the holding cylinder 22 shown in FIG. This holding cylinder 2
2 also has a cooling water passage 34 formed therein.
Cooling water from the holding cylinder 2 through the cooling water passage 34.
2 is cooled and discharged from the other connection port 36.

A holding wheel 38 is housed in the holding hole 37 of the holding cylinder 22. The holding ring 38 is provided with a large-diameter cylindrical portion 39 that fits exactly into the inner peripheral surface of the storage hole 37 of the holding cylindrical body 22.
And a holding portion 41 that forms a room 40 radially inward from the inner peripheral surface thereof, and an inward flange-shaped receiving portion 42 formed below the holding portion 41. The receiving portion 42 has an injection hole 43
Is formed. A lens holding ring 44 is provided on the receiving portion 42.
Is supported thereon, and a lens 45 is placed on the lens 45. Further, a lens pressing ring 46 is disposed on the periphery of the lens 45, and a spring pressing member 48 is connected to a holding ring 38 via a spring 47.
The upper and lower positions of FIG.
The two lens pressing rings 44 and 46 are made of a soft synthetic resin, for example, a fluororesin such as Teflon.

For example, a laser beam 50 from a carbon dioxide laser source passes through the inside of the mounting member 26, is condensed by a lens 45, follows a path indicated by reference numeral 51, passes through a nozzle tip 10, passes through a nozzle tip 10, and Irradiation is carried out to 70 and cutting processing is performed.

A connection port 53 is formed on a side portion of the holding cylinder 22, from which a first gas is supplied, and is injected from an injection hole 43 through a chamber 40 to the lower surface of the lens 45 in FIG. The lens 45 is cooled, and the injected first gas is supplied into the space 54 of the head main body 14 below the lens 45.

The base 24 is supplied with a cooling gas, for example, the same kind of gas as the first and / or second gas described later, from a connection port 82 and is injected into a space 84 from a nozzle 83 as an injection hole. The liquid is injected onto the upper surface of the lens 45 to cool the lens 45.

The mounting cylinder 15 is vertically displaced by adjusting the cap nut 18, whereby the distance between the first and second nozzles 58 and 66 of the nozzle tip 10 and the workpiece 70 is set optimally. The laser beam 50 can be adjusted so that the focal point of the laser beam 50 coincides with the workpiece 70, or alternatively, the injection regions of the first and second gases are accurately set.

Referring again to FIG. 1, the nozzle member 12
It has an operating portion 55 with a knurl on the outer peripheral surface, and an external screw 56 is further formed below the operating portion 55 to form a hollow inverted conical portion 57.
The lower portion of the inverted conical portion 57 is a first nozzle 58 whose outer peripheral surface has a right cylindrical shape. Outer screw 30,56,
The operating section 55, the inverted conical section 57, and the first nozzle 58 have a common axis 59. The nozzle member 12 has conical surfaces 60 and 61 formed therein, and further has a first cylindrical hole 62 which is coaxial with the axis 59 and has an inner peripheral surface parallel to the axis 59. The inner diameter D1 of the first nozzle hole 62 is 2 mmφ, and the outer diameter D2 of the first nozzle 58 is
Is 9 mmφ. Maximum outer diameter D of the upper end of the inverted conical portion 57
3 is 30 mmφ. Axis 59 of first nozzle hole 62
The length L1 in the axial direction having an inner peripheral surface parallel to
It is.

The cover member 13 is connected to an outer screw 56 of the nozzle member 12 and has a straight cylindrical portion 64 having an inner screw 63 which can be displaced along the axis 59, and is connected to a lower end of the straight cylindrical portion 64. It has a hollow inverted conical portion 65 and a second nozzle 66 connected to the inverted conical portion 65. The inner peripheral surface 67 of the second nozzle 66 is formed in a right cylindrical shape along the axis 59. The inner diameter D4 of the inner peripheral surface 67 is 11 mmφ, the outer diameter D5 is 16 mmφ, and the inner diameter D6 of the straight cylindrical portion 64 is
Is 44 mmφ. Furthermore, the axis 59 of the inner peripheral surface 67
Is 5 mm.

In the straight cylindrical portion 64 of the cover member 13, connection ports 68a are formed at a total of four locations at equal intervals (90 degrees in this embodiment) in the circumferential direction, and a second gas is formed from the connection ports 68a. Is supplied. The second gas is injected into the workpiece 70 through an annular second nozzle hole 68 between an outer peripheral surface of the first nozzle 58 and a circular inner peripheral surface 67 formed in the second nozzle 66. You.

FIG. 6 is a piping system diagram of the aforementioned embodiment of the present invention. When the first and second gases are the same type of gas, the on-off valve 72
After that, the first gas is supplied from the pipe 73 to the connection port 53, and the second gas is supplied from the pipe 74 to the four connection ports 68 a in total. A pressure reducing valve may be interposed in each of the pipes 73 and 74 so that the supply pressures of the first and second gases are different from each other. Further, the types of the first and second gases may be different from each other.

Referring to FIG. 7, the operation when cutting the workpiece 70 will be described. In FIG. 7, the configuration is simplified. The laser beam 50 is transmitted to the condenser lens 45.
From the first nozzle hole 62 to the workpiece 70
Irradiated on top. The first gas from the connection port 53 is supplied to the first nozzle hole 62 after being injected to the lens 45, and is then injected to the workpiece 70. When the workpiece 70 is an iron-based material such as mild steel, the first gas is oxygen, and is injected at, for example, 0.5 kgf / cm ² .
In order to maintain the purity of the first gas in the vicinity of the workpiece 70 without entraining the surrounding air and maintain the momentum of the first gas, a second gas such as oxygen is supplied from the connection port 68a. The second nozzle hole 68 is supplied and formed in an annular shape by the first and second nozzles 58 and 66.
Injected from. Thus, the dross 75, which is the molten metal of the workpiece 70, does not adhere to the surface of the workpiece 70 opposite to the head 11, that is, the lower surface of FIG.
The melted dross is blown off downstream (downward in FIG. 7) in the gas injection direction to prevent the dross 75 from adhering, thereby promoting the removal of the dross.

The first nozzle hole 62 and the nozzles 58 and 66
The distance L4 (see FIG. 2) between the annular second nozzle hole 68 and the center position in the width direction of the second nozzle hole 68 is, for example, 5
mm. Such first and second nozzle holes 62,
If the distance L4 between the first and second nozzles 68 is less than 3 mm, the first and second nozzle holes 62 and 68 are too close to each other, so that a large flow rate is sprayed on the workpiece 70 which is an iron-based material. It produces self-burning and burns. Conversely, if the distance L4 is 7 mm or more,
The distance between the first and second nozzle holes 62 and 68 is too large, and the first gas ejected from the first nozzle hole 62 may entrain air, resulting in reduced purity and difficulty in retaining momentum. Becomes Therefore, the distance L4 between the first and second nozzle holes 62, 68 is 3 mm or more,
It is selected in a range of less than mm, particularly preferably 5 mm. The radial width W1 of the annular second nozzle hole 68 in FIG. 2 may be, for example, 1 mm. Thereby, according to the experiment of the present inventor, when the output of the laser beam 50 is set to 3 kW, in the above-described prior art in which the cover member 13 is not provided, the thickness of the workpiece 70 is at most 22 to 25 mm. However, according to the above-described configuration of the present invention, it is possible to perform a cutting process with a thickness of 28 mm or more,
In addition, it was confirmed that the removal of dross was promoted and the dross grinding work by the grinder became unnecessary.

When the workpiece 70 is made of stainless steel, aluminum, or the like, the first and second gases may be inert gases such as nitrogen, argon, and air, as described above. The types of the two gases may be different from each other.

FIG. 8 is a bottom view of another embodiment of the present invention, which shows a configuration corresponding to FIG. 2 described above. It should be noted that, in this embodiment, the second nozzle hole 68
b is formed in the shape of a right column and a total of eight b are formed at equal intervals in the circumferential direction. The inner diameter D1 of the first nozzle hole 62, the second
Inner diameter D7 of nozzle holes 68b and their nozzle holes 6
The distance L5 between the first and second nozzles 68b is selected to a value that maintains the purity and momentum of the first gas from the first nozzle hole 62 and promotes the removal of dross.

FIG. 9 is a sectional view showing a simplified configuration of another embodiment of the present invention. This embodiment is similar to the previous embodiment, and corresponding parts are denoted by the same reference numerals. It should be noted that in this embodiment, a mixed gas of, for example, acetylene gas, which is an oxygen and a combustible gas, is supplied from the connection port 68a, and a flame 76 is supplied to the workpiece 70 from the annular second nozzle hole 68. Injected toward. The flame 76 further enhances the purity of the first gas and the holding power of momentum, and when the workpiece 70 is an iron-based material such as mild steel, it also has effects such as surface activation in cutting oxygen gas, and When the workpiece 70 moves relative to the head 11 in the cutting direction, the workpiece is preheated. Therefore, according to the experiment of the present inventor, the workpiece having a thickness of 50 mm or more can be cut. Was.

FIG. 10 is a simplified cross-sectional view of a part of another embodiment of the present invention. This embodiment is similar to the previous embodiment, and corresponding parts are denoted by the same reference numerals. Although the first nozzle hole 62 is formed in the nozzle 58 and the annular second nozzle hole 68 is formed by the cover member 13, it is similar to the above-described embodiment, but it should be further noted that in this embodiment, the second nozzle hole 62 is formed. One cover member 77 is provided, the third gas is supplied from the connection port 78, and the third gas is supplied from the annular third nozzle hole 80 between the inner peripheral surface of the third nozzle 79 and the outer peripheral surface of the second nozzle 66. A third gas or flame is injected. Other configurations are the same as those of the above-described embodiment. The third gas may be of the same type as the first and second gases, or may be of different types. According to the concept of the present invention, a plurality of annular nozzle holes may be formed coaxially.

The first gas and the second gas may be the same type of gas, but may be different types of gases.

[0037]

According to the present invention, the head body includes a first nozzle member having a first nozzle hole, and a mounting cylinder body to which the first nozzle member is removably mounted and an outward flange is formed. A first cap nut engaged with the outward flange of the mounting cylinder, an adjustment cylinder to which the first cap nut is screwed, and a holding cylinder to which the adjustment cylinder is attached and the lens is housed. It is comprised including. Therefore, by loosening the first cap nut, the mounting cylinder and the first nozzle member together with the first cap nut can be removed from the adjusting cylinder. In addition, since the first cap nut is screwed to the adjusting cylinder, the height of the first nozzle member can be adjusted according to the tightening position of the first cap nut. This makes it possible to adjust the focal point of the laser beam from the workpiece so that it coincides, or to set the injection regions of the first and second gases accurately.

The holding wheel has a large-diameter portion whose outer peripheral surface fits along the inner surface of the storage hole of the holding cylinder, and forms a room radially inward from the inner peripheral surface of the storage hole of the holding cylinder. Holding part,
A receiving portion that extends below the holding portion and protrudes radially inward from the inner peripheral surface of the holding portion; A receiving portion of such a holding ring supports a first lens press ring, a lens is mounted on the first lens press ring, and a second lens press ring is provided on the periphery of the lens. The second lens pressing ring is placed and pressed by a spring pressing member screwed to the holding ring. The first and second lens retaining rings are made of a soft synthetic resin, and the spring is maintained between the first and second lens retaining rings by the spring. In the first connection port formed in the holding cylinder,
A first gas is supplied from a first gas supply source, and the first gas is injected from the injection hole toward the lens through the chamber. The lens is cooled by the first gas injected from such an injection hole, and the injected first gas is supplied into a space below the lens, and is processed from the first nozzle hole of the first nozzle member. The first gas is injected into the material to prevent dross adhesion, and thus the first gas can simultaneously perform the two functions of cooling the lens and removing the dross.

Further, according to the present invention, a cooling water passage is formed at the bottom of the mounting cylinder, and cooling water is supplied to the cooling water passage, so that the mounting cylinder and the first nozzle member are cooled. Can be.

Further, according to the present invention, a cooling water passage is formed at the bottom of the holding cylinder, and the cooling water is supplied to the cooling water passage. It is possible to suppress a rise in temperature due to heat generation during transmission of laser light.

According to the present invention, the laser processing head is mounted on the XY table or the working end of the robot, and is moved in a desired direction, or the laser processing head is fixed. Even when the workpiece is moved in a desired direction, the first nozzle hole is configured so as to surround the entire circumference thereof with the second nozzle hole, so that the purity and momentum of the first gas are reduced as described above. It will always be possible to retain and promote the removal of dross.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a nozzle tip 10 including a nozzle member 12 and a cover member 13 according to one embodiment of the present invention.

FIG. 2 is a bottom view of the nozzle tip 10. FIG.

FIG. 3 shows a laser processing head 1 including a nozzle tip 10;
FIG. 1 is a cross-sectional view illustrating the entire configuration of the first embodiment.

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3;

FIG. 5 is a cross-sectional view taken along the line VV of FIG. 3;

FIG. 6 is a piping system diagram of the embodiment shown in FIGS.

FIG. 7 is a simplified cross-sectional view showing a state where the workpiece 70 of the embodiment shown in FIGS. 1 to 6 is cut.

FIG. 8 is a bottom view of a nozzle tip according to another embodiment of the present invention, showing a configuration corresponding to FIG.

FIG. 9 is a cross-sectional view showing a simplified configuration and operation of another embodiment of the present invention.

FIG. 10 is a partial cross-sectional view of still another embodiment of the present invention.

FIG. 11 is a simplified cross-sectional view showing the configuration of the prior art.

FIG. 12 is a bottom view showing the prior art nozzle 4 shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Nozzle chip 11 Laser processing head 12 Nozzle member 13 Cover member 14 Head main body 15 Mounting cylinder 17 Adjusting cylinder 22 Holding cylinder 24 Base 26 Mounting member 38 Holding wheel 40 Room 43 Nozzle 45 Lens 53, 68a Connection port 54 Space 58 First nozzle 62 First nozzle hole 66 Second nozzle 68 Second nozzle hole

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mamoru Nishio 3-1-1, Higashi-Kawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. Kobe Plant (72) Inventor Takeaki Aoki Higashi-Kawasaki, Chuo-ku, Kobe-shi, Hyogo 3-1-1, Kawamachi Kobe Plant, Kawasaki Heavy Industries, Ltd. (56) References JP-A-2-99293 (JP, A) JP-A-57-130791 (JP, A) JP-A-3-11094 (JP, A) A) JP-A-5-245685 (JP, A) JP-A-61-169186 (JP, A) JP-A-59-104289 (JP, A) Japanese Utility Model Application No. Sho 62-34987 (JP, U) Japanese Utility Model Utility Model No. 60 -186986 (JP, U) Japanese Utility Model Application Hei 3-31081 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23K 26/00-26/18

Claims (3)

(57) [Claims] 1. A head body having an optical path for guiding laser light and irradiating a workpiece with laser light from a first nozzle hole; and a head body provided on the head body and having a common axis with the first nozzle hole. And a cover member forming a second nozzle hole surrounding the first nozzle hole on the outer periphery of the first nozzle hole, wherein the first gas is supplied to the space in the head body and the outer periphery of the head body is provided. A second gas is supplied to a space between the surface and the inner peripheral surface of the cover member, and the head body has a first nozzle member having a first nozzle hole, and the first nozzle member is detachably attached, A mounting cylinder having an outward flange formed thereon, a first cap nut for locking the outward flange of the mounting cylinder, an adjusting cylinder to which the first cap nut is screwed, and an adjusting cylinder attached And a holding cylinder in which the lens is housed. A large-diameter cylindrical portion in which the outer peripheral surface is fitted along the inner peripheral surface of the storage hole of the holding cylinder, and a room radially inward from the inner peripheral surface of the storage hole of the holding cylinder. A holding ring having a holding portion that forms the following and a receiving portion that extends below the holding portion and protrudes inward in the radial direction from the inner peripheral surface of the holding portion is housed. A first lens holding ring made of a soft synthetic resin, which is open toward the room and has an injection hole communicating with the room, is supported, and a lens is mounted on the first lens holding ring, and the first lens holding ring is mounted on the first lens holding ring. A second lens holding ring made of a soft synthetic resin is placed on the peripheral portion, and a spring is placed on the second lens holding ring, and the spring is screwed to the holding ring from above the spring. A first connection port communicating with the room is formed in the holding cylinder body. Laser machining head first gas from the first gas supply source to the first connection port, characterized in that it is supplied. 2. The laser processing head according to claim 1, wherein a cooling water passage to which cooling water is supplied is formed at a bottom of the mounting cylinder. 3. The laser processing head according to claim 1, wherein a cooling water passage to which cooling water is supplied is formed at a bottom of the holding cylinder.