JPH10193151A - Laser machining torch and perforation method for its nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely perforate, with a machining nozzle attached, by emitting a laser beam to the unperforated nozzle attached to the tip end of a laser machining torch. SOLUTION: A laser generator 1 is constituted of a discharge tube 100, an output mirror 101 attached airtightly through a mirror holder 201, 202, and a reflected mirror 102. The output mirror 101 is cooled by a cooling medium 103. The cooling state of the output mirror 101 is controlled so that the diameter of the output laser beam emitted from the generator 1 is made larger than that of a normal machining laser beam. While the cooling state is so controlled, the laser beam is emitted to an unperforated machining nozzle at the tip end of the laser machining torch 9, perforating the nozzle, so that the perforated nozzle is provided for the machining mode as it is. Consequently, the construction of the laser machining torch itself is also simplified, enabling cost reduction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser for constantly aligning the center of a laser beam with the center of a hole of a processing nozzle when irradiating a laser beam condensed by a condenser lens onto a workpiece. The present invention relates to a method for drilling a nozzle of a laser processing torch in a processing apparatus and a laser processing torch.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a laser processing apparatus to which the present invention is applied. 1 is a laser oscillator, 2 is a laser beam output from a laser oscillator 1, and 3 is a laser beam that reflects a laser beam 2. Further, it is a bent mirror for making the laser beam 2 incident on a condenser lens 6 described later. 4 is a central axis of the laser processing torch 9, 5 is a laser light guide tube for protecting the optical path of the laser light 2, 6 is a condenser lens for condensing the laser light 2, 7 is a condenser lens 6 Focused laser light, 8
Denotes a processing nozzle. Reference numeral 9 denotes a condenser lens 6, a processing nozzle 8, a nozzle holder 11 described later, and a torch body 1.
2 shows a laser processing torch consisting of No. 2. The workpiece 20 is mounted on a processing table 21 and is provided with an NC (Num).
erical Control), PLC (Programmable Logic Control)
ler) and the like.

Prior to processing, the laser oscillator 1 is appropriately cooled to a desired state, and a laser beam having a desired beam diameter (= stationary processing laser light) is supplied from the laser oscillator 1 while supplying power to the laser oscillator 1. Output. This steady processing laser light passes through the bend mirror 3 and the condenser lens 6 and is taken out of the laser processing torch together with the assist gas from the axis of the nozzle hole at the tip of the laser processing torch 9. The laser processing is performed by irradiating the laser beam 7 to the workpiece 20 and moving the laser beam 7 and the workpiece 20 relatively appropriately.

Conventionally, for example, a laser processing torch shown in FIG. The laser processing torch 9
A lens holder 16 on which the condenser lens 6 is mounted, a holder mount 17 mounted on the torch body 12 in a direction orthogonal to the laser light 7 supporting the lens holder 16, and a position of the holder mount 17 orthogonal to the laser light 7. Three or four adjustment screws 13 and 14 that can be adjusted in the direction, a nozzle holder 11, a processing nozzle 8 having a through hole in an axial center portion, and a set screw 15 for attaching the processing nozzle 8 to the nozzle holder 11. It is composed of

The adjusting screws 13 and 14 are appropriately adjusted so that the laser light 7 and the nozzle hole 1 are adjusted as shown in FIG.
Positioning is performed so that 0 is coaxial. By the way, the wavelength of laser light used for processing is in the infrared region, and is invisible to the operator. Therefore, when adjusting so that the condensed laser light 7 is located at the center position of the nozzle hole 10, for example, an acrylic plate, paper tape, or the like is installed or adhered under the nozzle hole 10, and the laser light 7 is applied as described above. By irradiating an acrylic plate, paper tape, or the like, the positions of the holes drilled in the acrylic plate, paper tape, or the like are confirmed. Thus, the amount of eccentricity between the nozzle hole 10 and the laser beam 7 is determined, and the position of the condenser lens 6 is adjusted using the adjusting screws 13 and 14 by the amount of eccentricity. The above confirmation and adjustment work is performed by using the laser beam 7 and the nozzle hole 10.
It had to be repeated until they were coaxial.

Further, conventionally, there has been proposed a laser processing torch shown in FIG. 6 which does not require a lens adjustment operation in a direction orthogonal to a laser beam. The components other than the processing nozzle 8 and the height adjusting spacer 18 in FIG. 6 are the same as the components of the laser processing torch shown in FIG. That is, in the laser processing torch shown in FIG. 6, a processing nozzle 8 having no hole through which laser light is provided on the bottom surface of the processing nozzle 8 is used.

First, as shown in FIG. 6 (A), the processing nozzle 8 having no hole in the bottom is pushed in the Z1 direction, and the processing nozzle 8 is fixed to the nozzle holder 11 by the set screw 15. In this state, the bottom surface of the processing nozzle 8 is drilled by the steady processing laser light output from the laser oscillator 1. In this case, the bottom surface of the processing nozzle 8 is drilled where the beam diameter is not so narrow. At this time, the diameter of the nozzle hole 10 formed in the bottom surface of the processing nozzle 8 is d1.
And

Next, as shown in FIG. 6B, the processing nozzle 8 is detached from the nozzle holder 11 and the nozzle holder 1 is removed.
The processing nozzle 8 is fixed to the nozzle holder 11 by the set screw 15 in a state where the height adjustment spacer 18 is attached between the nozzle 1 and the processing nozzle 8. In this state, the workpiece 20 is laser-processed by the steady processing laser light output from the laser oscillator 1.

In this case, the laser beam 7 irradiated to the workpiece 20 side, that is, the Z2 direction side via the laser processing torch has a slightly narrowed shape in the Z2 direction, and the height is adjusted. Since the tip of the processing nozzle 8 attached via the spacer 18 is attached with its position displaced in the Z2 direction, focusing on the tip of the processing nozzle 8, the beam diameter d2 passing through the processing nozzle 8 is the hole diameter. less than d1.
Therefore, the laser beam 7 does not hit the edge of the nozzle hole 10 but smoothly passes through the nozzle hole 10 and
Can be laser-processed.

[0010]

In the checking / adjusting operation of adjusting the adjusting screws 13 and 14 while irradiating the acrylic plate, paper tape, or the like with the laser beam 7 and checking the positions of the drilled holes, the amount of eccentricity is large. There is a problem that the adjustment work is troublesome and takes a lot of time since it is necessary to make the adjustment repeatedly until the error disappears.

When the nozzle hole 10 is drilled on the bottom surface of the processing nozzle having no hole, the processing nozzle 8 and the height adjusting spacer 18 are formed at the time of nozzle drilling and at the time of laser processing after the nozzle drilling. The removal and mounting operations are troublesome, and the height adjustment spacer 18 is relatively small, so that the removed height adjustment spacer 18 is lost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to eliminate the need for fine adjustment of each part of a laser processing torch for making a laser beam and a nozzle hole coaxial. Nozzle drilling method and laser for laser processing torch in laser processing device that can easily and reliably drill holes when drilling the bottom surface of unprocessed nozzles and can reliably process workpieces It is to provide a processing torch.

[0013]

The first invention is applied to a method for drilling a nozzle of a laser processing torch in a laser processing apparatus. The feature is that the laser beam is processed by laser while controlling the cooling state of the laser oscillator so that the beam diameter of the output laser beam output from the laser oscillator is larger than the beam diameter of the steady processing laser beam. Irradiating a processing nozzle without a hole attached to the tip of the torch to make a hole in the processing nozzle. The second invention is applied to a laser processing torch. The feature of the laser processing torch is that a laser beam larger than the beam diameter of the regular processing laser beam is used to make a hole in a processing nozzle without a hole attached to the tip of the laser processing torch, and the laser processing torch is used as it is. It is to be attached to. The third invention is characterized in that, in the second invention, the processing nozzle is screwed to a tip of a laser processing torch before drilling the processing nozzle.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. 1 to 3, a laser oscillator 1 mainly includes a discharge tube 100 supported on an optical bench.
And a mirror holder 20 at the front and rear portions of the discharge tube 100 in the axial direction.
An output mirror 101 and a reflecting mirror 102 are hermetically attached via the reference numerals 1 and 202. 104 is the refrigerant 1
03, for example, by circulating cooling water,
This is a refrigerant pipe for cooling the output mirror 101 and the reflecting mirror 102 supported by 202.

Further, a flow rate changeover switch 105 is provided in the refrigerant pipe provided on the output mirror 101 side. The flow rate changeover switch 105 is switched between a drilling mode in which the flow rate of the coolant is reduced when drilling holes in the nozzle and a processing mode in which the flow rate of the coolant is suitable for processing before laser processing the workpiece. The above components constitute the laser oscillator 1.

Reference numeral 2C denotes a laser beam output from the laser oscillator 1, and reference numeral 3 denotes a vent mirror that reflects the laser beam 2 and causes the laser beam 2 to enter a condenser lens 6 described later. 4
Is a central axis of the laser processing torch 9, 5 is a laser light guide tube, 6 is a condenser lens fixedly attached to the laser processing torch 9, and 7 is a laser beam collected by the condenser lens 6. . The laser processing torch 9 includes a condenser lens 6 and
Processing nozzle 8, nozzle holder 11, and torch body 1
2, the external thread of the processing nozzle 8 is screwed to a female screw threaded at the distal end of the nozzle holder 11, and the processing nozzle 8 is attached to the distal end of the laser processing torch 9. The details of the processing nozzle 8 will be described later.

In the above configuration, first, the state of the output mirror 101 by switching the flow rate of the refrigerant will be described. In FIG. 2, a mirror holder 201 supporting an output mirror 101 is cooled directly or indirectly by a coolant 103. Reference numeral 203 denotes an airtight member for sealing the refrigerant 103 so that the refrigerant 103 does not leak from the mirror holder 201, for example, an O-ring. Therefore, as a result, the output mirror 101 is appropriately cooled by the refrigerant 103.

When the flow rate changeover switch 105 is switched to the processing mode, the flow rate of the refrigerant to the output mirror 101 increases, and the laser beam from the laser oscillator 1 for steady processing laser light, that is, the laser processing for the workpiece is performed. A laser beam with a beam diameter of That is, FIG.
As shown in (A), when the laser beam passes through the output mirror 101, the output mirror 101 is heated by the heat of the laser beam.

The output mirror 101 is sufficiently cooled by the refrigerant 103 supplied in a large amount, and the heat of the output mirror 101 heated by the laser beam is carried out of the output mirror 101. It is not affected by heat from the laser light. That is, almost no change occurs in the planar state of the output surface of the output mirror 101. For this reason,
The laser beam 2C passing through the output mirror 101 is
The laser beam travels in the X1 direction with almost no change from the state of the laser beam incident on the laser beam.

When the flow rate switch 105 is switched to the drilling mode, the flow rate of the refrigerant to the output mirror 101 decreases. In this case, as shown in FIG. 2B, a state occurs in which heat generated by the laser beam absorbed by the output mirror 101 is not sufficiently carried away by the refrigerant having a small flow rate. Therefore, the output mirror 101 is heated and expanded by the amount of heat gradually left in the output mirror 101.

By the way, in the laser oscillator 1,
Since the laser light in a desired state is output while the laser light is repeatedly excited between the output mirror 101 and the reflecting mirror 102, when attention is paid to the output mirror 101, the inner surface of the output mirror 101 is concave. On the other hand, for example, the outer surface of the output mirror 101 is formed in a planar shape. That is, the output mirror 101
Is thick in the radially outer portion with respect to the center portion.

For this reason, as described above, when the output mirror 101 is heated and expanded by the gradually remaining heat, the thin portion of the shaft core is pulled toward the outer thick portion.
Although the distortion due to this is slight, if the state due to this distortion is enlarged and described, the outer surface of the output mirror 101 is slightly concave outward in the radial direction, that is, a so-called concave state. For this reason, the laser beam 2D that has passed through the output mirror 101 is in a state of slightly spreading outward in the radial direction in the beam traveling direction. For this reason, the shape of the laser beam becomes divergent near the bent mirror 3 in the beam traveling direction, that is, the X1 direction, and the laser beam reflected by the bent mirror 3 propagates in a state larger than the beam diameter of the steady processing laser beam.

By the way, in the present invention, a processing nozzle 8 having no hole through which laser light is provided on the bottom surface of the processing nozzle 8 is used. That is, as shown in FIG. 3, the processing nozzle 8 having no hole in the bottom surface is screwed to the nozzle holder 11 at the tip of the laser processing torch 9.

As described above, in the drilling mode, the amount of the refrigerant supplied to the output mirror 101 is reduced. As a result, the laser beam reflected by the vent mirror 3 is smaller than the beam diameter of the steady processing laser beam. Is also propagated in a large state. Accordingly, the tip shape of the laser beam 7D in the drilling mode that has passed through the condenser lens 6 by the bent mirror 3 has a wider angle than the laser beam 7C in the processing mode. That is, as shown in FIG. 3A, the laser beam 7 in the drilling mode whose tip shape has a wider angle than the laser beam 7C in the processing mode.
D is irradiated to the processing nozzle 8 having no hole in the bottom surface, and a through hole is drilled. The diameter of the nozzle hole 10 formed in the bottom surface of the processing nozzle 8 at this time is d3.

As described above, in the state where the bottom surface of the processing nozzle 8 is drilled, that is, a hole is formed in the processing nozzle 8 having no hole attached to the tip of the laser processing torch with a laser beam larger than the beam diameter of the steady processing laser beam. Drilling is performed in a processing mode with the perforated processing nozzle 8 as it is. That is, the flow rate changeover switch 105 shown in FIG. 1 is appropriately switched to the processing mode, and after a lapse of a desired time, the workpiece 20 is laser-processed by the steady processing laser beam 7C output from the laser oscillator 1.

In this case, as shown in FIG. 3 (B), the laser beam 7C irradiated to the workpiece side, that is, the Z2 direction side via the laser processing torch 9 has a sharp shape directed to the Z2 direction. The beam diameter d4 passing through the nozzle hole 10 of the processing nozzle 8 is smaller than the hole diameter d3 of the nozzle hole 10, and the nozzle hole 10 and the laser beam 7C are concentric. Therefore, since the laser beam 7C passes toward the workpiece without hitting the edge of the nozzle hole 10, the workpiece 20 can be laser-processed in a good state.

As is apparent from the above description, the direction of the nozzle hole of the laser processing torch according to the present invention is such that the beam diameter of the output laser light output from the laser oscillator is larger than the beam diameter of the steady processing laser light. In order to pierce the processing nozzle by irradiating the laser light to a processing nozzle without a hole attached to the tip of a laser processing torch while controlling the cooling state by a flow rate changeover switch of a laser oscillator, a conventional example 1 is used.
(= FIG. 5) Fine laser processing to adjust the respective parts of the torch for making the laser beam and the nozzle hole coaxial, particularly the adjustment of the condenser lens 6, is unnecessary and easily processed. The bottom of the nozzle can be drilled.

In the drilling mode, a large hole is drilled in the bottom surface of the processing nozzle having no hole, and then the laser beam is applied in a state where the flow rate changeover switch is switched to the processing mode. Processing of the workpiece is performed. That is, while the processing nozzle 8 is still attached to the nozzle holder 11, drilling of the bottom surface of the processing nozzle and processing of the workpiece by laser light are performed. It becomes unnecessary. Of course, there is no need to remove or attach the conventionally required height adjusting spacer 18, and the height adjusting spacer 1
There is no risk of losing 8. In addition, the number of parts of the laser processing torch is reduced and the cost is reduced accordingly.

[0029]

As is clear from the above description, the nozzle drilling method and the laser drilling torch of the laser drilling torch according to the present invention switch the flow rate changeover switch between the drilling of the nozzle and the laser drilling. At the time of drilling, the bottom of the processing nozzle is drilled with the laser beam whose beam diameter is increased by reducing the coolant flow rate, and at the time of laser processing, the coolant flow rate is increased so that the sharp laser beam is processed. Irradiation is performed on the workpiece side concentrically with the nozzle hole formed in the nozzle.

Therefore, it is not necessary to finely adjust each part of the laser processing torch for making the laser beam and the nozzle hole coaxial, and when drilling the bottom surface of the processing nozzle with no holes, the processing is performed. With the nozzle still attached,
Drilling can be performed easily and reliably, and processing of a workpiece can be performed reliably. Needless to say, the structure of the laser processing torch itself is simplified, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a laser processing apparatus equipped with a laser processing torch of the present invention.

FIG. 2 is a view for explaining a state change of an output mirror 101 in FIG. 1;

FIG. 3 is a view for explaining a nozzle drilling state and a laser processing state in FIG. 1;

FIG. 4 is a schematic diagram showing a laser processing apparatus to which the present invention is applied;

FIG. 5 is a view showing a conventional laser processing torch;

FIG. 6 is a view for explaining a nozzle drilling state and a laser processing state in another conventional laser processing torch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laser oscillator 3 ... Bent mirror 6 ... Condensing lens 7 ... (Condensed) laser beam 8 ... Processing nozzle 9 ... Laser processing torch 11 ... Nozzle holder 100 ... Discharge tube 101 ... Output mirror 102 ... Reflecting mirror 103 ... Refrigerant 104 ... Refrigerant piping 105 ... Flow rate changeover switch 201, 202 ... Mirror holder

Claims (3)

[Claims] 1. A cooling state of a laser oscillator is controlled so that a beam diameter of an output laser beam output from a laser oscillator is larger than a beam diameter of a steady processing laser beam.
A method for drilling a nozzle of a laser processing torch in a laser processing apparatus for piercing a processing nozzle by irradiating the laser beam to a processing nozzle having no hole attached to the tip of the laser processing torch. 2. A hole is formed in a processing nozzle having no hole attached to the tip of the laser processing torch with a laser beam larger than the beam diameter of the laser beam for regular processing, and the perforated processing nozzle is attached to the laser processing torch as it is. Laser processing torch. 3. The laser processing torch according to claim 2, wherein the processing nozzle is screwed to a tip of the laser processing torch before drilling.