JPH06114586A - Laser beam emitting unit - Google Patents

Abstract

PURPOSE:To provide the laser beam emitting unit which accomplishes simultaneously and easily intensification of a spatter removing effect, prevention of optical pollution by reflection of spatters, prevention of nozzle clogging and observability of plasma and cover glass. CONSTITUTION:A holder 31 is located between a laser beam emitting port 2 and a single lens 4, demarcates passing space through which a laser beam is passed, has first and second blow-air blowoff parts 31a and 31b to blowoff the blow air, besides, consists of only an inner wall surface part to demarcate the passing space and at least is not provided with a baffle member to baffle blowoff of the blow air in the blowoff direction of the blow air. Namely, in order to reduce the reflection of spatters, the shape eliminating the whole wall surface other than a blowoff port of the blow air, a funnel-shaped assisting gas nozzle part 8 and a column to hold these is provided on an intermediate path till attaining the single lens 4 from works to be welded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser emission unit, and more particularly to a blow air blowout section for removing spatters and fumes scattered from a welding work by laser irradiation, and a reflection of the spatters on the inner wall of a cylinder contaminating an optical system. The present invention relates to a laser emission unit including a holder having an assist gas ejection nozzle for eliminating it.

[0002]

2. Description of the Related Art Generally, a laser emitting unit of this type is located between a laser emitting port that faces a workpiece, a lens that emits laser light from the laser emitting port, and the laser emitting port and the lens, and allows the laser to pass therethrough. It is mainly composed of a holder that defines the passage space by the inner wall of the cylinder.

Further, in this holder, blow air is blown into the passage space to remove spatter and fumes scattered from the welding work, and an assist gas for eliminating reflection of spatter on the inner wall of the cylinder that contaminates the lens. Alternatively, an assist gas jet nozzle for jetting the shield gas is provided. Incidentally, as the shape of the conventional laser emission unit, generally, a continuous circular shape is integrated from the condensing optical system such as a lens and a mirror to the blow air blowing portion and the assist gas ejection nozzle.

[0004]

However, the holder of the above laser emitting unit has the following problems. Spatters and fumes (metal vapors) scattered from the welding work were reflected on the inner wall of the cylinder and moved upward, causing damage to the light collection optical system. The flow rate of the air blow for spatter removal was low, and the flow rate of the air blow after blowing was also low. The air blow-off part had only one step, and the effect of removing spatter was low. Since the tip of the assist gas ejection nozzle is clogged with spatter and fumes, the shield gas often does not come out. Since the laser emission unit was configured as a continuous cylindrical type, laser-induced plasma enters the unit, so it is difficult to observe plasma light spectroscopically, perform laser process monitoring, and observe the spatter protection glass. Met.

That is, these problems occur simultaneously during laser welding. Therefore, in order to construct a laser emission unit that is industrially satisfactory, a method of simultaneously solving all of these problems has been desired.

In view of the above drawbacks, the technical problem of the present invention is to simultaneously enhance the effect of removing spatter, prevent optical system contamination due to reflection of spatter, prevent nozzle clogging, and observe plasma and protective glass at the same time. Another object is to provide a laser emission unit that can be easily achieved.

[0007]

The present invention adopts the following constitution in order to solve the above technical problems. Firstly, a laser emitting unit of the present invention includes a nozzle portion having a laser emitting port that faces a workpiece, a laser emitting optical system that emits laser light from the laser emitting port, the laser emitting port, and the laser emitting optical system. And a holder having a blow air blowing portion for blowing the blow air in a direction substantially orthogonal to the laser emitting direction in the passing space, the holder being located between the holder and the nozzle. The connecting member connects the part to the laser emission optical system side, and the connecting member opens the periphery of the passage space to the outside.

That is, the laser emission unit of the present invention has an assist gas nozzle holder provided with an air blow blowout portion. In the laser emission unit, spatters and fumes scattered from the welding work by laser irradiation reach the optical system. In order to eliminate the reflection of spatter in the intermediate path up to, the wall surface in the blowing air blowing direction is removed.

In other words, in the laser emitting unit of the present invention, in order to reduce the reflection of spatter, the blow air blowing port, the assist gas nozzle, and the support for holding these are provided in the intermediate path from the welding work to the laser emitting optical system. Except for all the walls except for the shape. This strut is the minimum necessary strut for providing the blow air outlet and holding the nozzle portion.

Secondly, in a preferred state of the laser emitting unit of the present invention, in the laser emitting unit, the blow air blowing portion has first and second blow air blowing ports facing the passage space. It is what

It can be said that the laser emitting unit in the preferred state of the present invention is provided with a plurality of blow air blowing portions in order to ensure the effect of removing spatter. Third
In a preferred state of the laser emission unit of the present invention, in the laser emission unit, when the separation distances of the first and second blow air outlets from the optical system converging point are L1 and L2, The first and second blow air outlets are characterized by being arranged with a separation distance ratio of substantially L1: L2 = 1: 2.

That is, a particularly preferred embodiment of the present invention is
In order to optimize the spatter removal effect, the distance ratio of the first and second blow air outlets from the welding work was set to approximately L1: L2 = 1: 2.

Fourthly, in a preferred state of the laser emitting unit of the present invention, in the laser emitting unit, the first and second blow air outlets have at least a width of 3
It is characterized by exhibiting a slit shape of mm or less.

That is, in the laser emission unit of the present invention, in order to increase the flow velocity of the blow air after being blown, the shape of the blow air blowout port which is the outlet of the blow air blowout section is a fine slit.

Fifth, a preferable state of the laser emission unit of the present invention is a laser emission port that faces a workpiece, and a laser emission optical system that emits laser light from the laser emission port.
It has a holder that is located between the laser emission port and the laser emission optical system and defines a passage space through which the laser passes, and the holder assists from near the laser emission port toward the workpiece. An assist gas ejection nozzle for ejecting gas is provided, and the assist gas ejection nozzle is characterized by having a copper alloy.

That is, in a preferred state of the laser emission unit of the present invention, the material of the assist gas ejection nozzle is a copper alloy in order to prevent the spatter and fume from adhering to the assist gas ejection nozzle which is the assist gas ejection nozzle. It is a thing.

Sixth, a preferable state of the laser emitting unit of the present invention is that in the laser emitting unit, the copper alloy is a copper chromium alloy.

That is, the preferred state of the laser emission unit of the present invention is, more preferably, the material of the assist gas ejection nozzle is a Cu--Cr alloy in order to prevent spatter and fume from adhering to the assist gas ejection nozzle. It is characterized by being. The nozzle used in the present invention using these materials can be manufactured at low cost by machining such as cutting.

Seventh, a preferable state of the laser emission unit of the present invention is that the laser emission unit of any one of the first to fifth aspects of the present invention has an assist gas ejection nozzle made of a copper-chromium alloy. It is a feature.

Eighth, a preferable state of the laser emitting unit of the present invention is that in the laser emitting unit, a protective filter for optically protecting the laser emitting optical system is provided in the passage space. To do. The protective filter may be transparent protective glass, for example.

Ninth, a preferable state of the laser emitting unit of the present invention is characterized in that the holder has a diameter dimension that allows laser-induced plasma to be visually spectroscopically observed or laser process monitoring can be performed. It is a thing.

That is, in a preferable state of the laser emission unit of the present invention, since the emission unit is composed of a large aperture type assist gas nozzle holder, laser-induced plasma can be observed spectroscopically and laser process monitoring is performed. It is possible. It is also easy to observe the spatter protection glass.

In the present invention, the materials to be welded are mainly composed of transition metals such as A1 alloy, Cu alloy, carbon steel, stainless steel, Ni alloy, Zn alloy, Mg alloy, Mo alloy, and Ti alloy. It is preferable to use an alloy or the like, an alloy obtained by subjecting them to a surface treatment such as plating (particularly a Zn-plated steel plate), various ceramics, and various glasses.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the laser emitting unit of the present embodiment is connected to the tip of the optical fiber 1. The optical fiber 1 guides laser light emitted from a laser device (not shown) to this unit.

This unit has a main body 3, and the main body 3
Has a tubular body portion 5 in which the single lens 4 is installed, and a tip unit portion 6 connected to the tubular body portion 5. The tip unit portion 6 is composed of a connecting cylinder portion 7, a post-shaped holder 31 following the connecting cylinder portion 7, and a funnel-shaped funnel-shaped assist gas nozzle portion 8 having a tapered tip.

The connecting cylinder portion 7 and the cylindrical body portion 5 of the tip unit portion 6 are connected to each other so that they can be inserted into and removed from each other. Corresponding to the holder 31, a passage space A through which the laser passes is formed between the laser emission port and the single lens 4 which is the laser emission optical system.

A laser emission port 2 is provided at the tip of the funnel-shaped assist gas nozzle portion 8 so that the laser beam focused by the single lens 4 passes through the passage space A and is emitted from the laser emission port 2. ing.

In front of the laser exit side of the single lens 4,
A protective glass 9 as a transparent filter is inserted between the laser emission port 2 and the single lens 4 at the connecting portion between the tubular body portion 5 and the connecting tubular portion 7.

Next, as described above, the holder 31 is located between the laser emission port 2 and the single lens 4 and conceptually defines the passage space A through which the laser passes.
Has a pillar shape, and therefore, most of the area around the passage space A is open to the outside. The holder 31 has a passage space A.
Further, it has first and second blow air blowing portions 31a and 31b for blowing blow air.

In other words, the holder 31 has only the minimum width necessary to provide the first and second blow blowout portions 31a, 31b along the passage space A, and at least blows blow air, or No baffle member that prevents the blow air from escaping from the passage space is provided in the blow air blowing direction. That is, in order to reduce the reflection of spatter, the intermediate path from the welding work to the single lens 4 has a shape in which all of the wall surfaces other than the blow air blowout port, the funnel-shaped assist gas nozzle portion 8 and the columns holding these are removed. . Therefore, the holder 31
Was able to form the laser-induced plasma with a spectroscopically visible or laser process monitorable diameter. Also, spatter protection glass 9
Is also easy to observe.

Furthermore, in order to optimize the effect of removing spatter, the first and second blow air blowing portions 31a and 31 are provided.
The separation distances L1 and L2 of the outlets of b are substantially L
They are arranged with a separation distance ratio of 1: L2 = 1: 2.

Referring also to FIG. 2, the outlets of the first and second blow air blowing portions 31a and 31b have a slit shape with a width of 3 mm or less, the air blow velocity is high, and the spatter removing effect is large. Has been further strengthened.

Further, slit-shaped air inlets 32a, 32 are provided along both sides of the slit-shaped air outlet.
a, 32b, 32b are provided. When blown air is blown out from the air outlet, outside air is prevented from flowing into the passage space A through the slit-shaped air inlets 32a, 32a, 32b, 32b and causing turbulent flow in the passage space A.

The first and second blow air blowing portions 31a and 31b are connected to an air compressor or a nitrogen gas source, and the air blow is exhausted from the release surface around the passage space A.

Next, in the funnel-shaped assist gas nozzle portion 8, the gas introduction portion 16 and the inner nozzle portion 1 having a concentric circular cross section.
0 are provided to form the gas flow path 12. As a result, the gas flow path 12 is opened around the laser emission port 2,
The assist gas ejection port 13 is formed. The funnel-shaped assist gas nozzle portion 8 is made of a Cu-Cr alloy in order to prevent spatter and fume from adhering to the nozzle.

Next, the result of the sputter adhesion test to the optical system protection filter, which was carried out using the laser emitting unit in this embodiment, is shown below. The laser emission conditions and the optical system used are shown below.

Laser: pulse YAG (pulse Nd: Y
AG) Laser (wavelength 1.06 μm) Multimode average output 357 (W) * Value before optical system protection filter.

Repetition frequency 8 (PPS) Optical system: Focal length f 120 (mm) Air blow blowout flow rate Upper 100 l / min Lower 11
0 l / min Spread angle θ. 14.5 ° (numerical aperture NA = sin θ.) Just focus Optical system protection filter: glass plate with AR coating on both sides JIS G3302 SGCC: ZMO, F06 (L100 (mm) x W30 (mm) ) × T1.0 (mm)), and the two sheets were overlapped and welded. The welding speed is 50 (cm / min), the welding length is 20 (mm), and the assist gas is Ar.

Further, as an accelerated test welding method, ten welding beads were continuously drawn at intervals of 5 mm on one set of welding work using a 6-axis articulated robot. From the experimental results of converting the number of beads in the continuous 10-bead method into the number of double-lap welding of a normal 20 mm bead, 100 beads in the continuous 10-bead method correspond to approximately 8,000 in normal welding.

As a result of the experiment, the reduction rate of the YAG laser light transmission amount with respect to the initial value after continuous 100 bead welding was 8.4.
%Met. The tensile shear load of the welded work before and after the experiment hardly changed. (Comparative Example) As a comparative example, a completely similar acceleration test was performed on a conventional continuous cylindrical emitting unit. As a result, the reduction rate of the YAG laser light transmission amount with respect to the initial value after continuous 100 bead welding was 15.6%. there were. The tensile shear load of the welded work before and after the experiment was reduced by about 80%.

As can be seen from the test results, the laser emission unit of this embodiment can be manufactured at low cost using ordinary materials, and the spatter and fume (metal vapor) scattered from the welding work can be produced. Since the walls that collide and reflect with are removed as much as possible, the effect of removing spatter is enhanced. Further, the spout removal effect is further enhanced by adopting a larger diameter at the inlet of the air blow-out portion to increase the flow rate of the air blow and a narrow slit at the outlet of the air blow-out portion to increase the air blow velocity. Furthermore, the air blow-off part has a two-stage structure, so the effect of removing spatter is ensured. In addition, since copper-chromium alloy is used as the spatter adhesion preventing nozzle, spatter and fumes do not adhere to the tip of the shield gas blowing nozzle at all, and the inside of the nozzle tip is not clogged with spatter and fumes. Further, since the emission unit is composed of a large aperture type assist gas nozzle holder, laser-induced plasma can be observed spectroscopically and laser process monitoring can be performed. It is also easy to observe the spatter protection glass.

[0042]

As described above, according to the present invention, spatters and fumes (metal vapor) scattered from the welding work.
By removing as much as possible the wall that collided and reflected, the spatter removal effect was enhanced.

Further, since the entrance of the air blow blow-out portion has a large diameter for increasing the flow rate of the air blow and the air blow blow-out portion has a narrow slit for increasing the air blow flow velocity, the effect of removing spatters is further enhanced.

Furthermore, since the air blow-off portion has a two-stage structure, the effect of removing spatter is ensured. In addition, since a copper-chromium alloy was used as the spatter adhesion prevention nozzle, spatter and fumes did not adhere to the tip of the shield gas blowing nozzle at all, and the inside of the nozzle tip became boring due to spatter and fumes.

Further, since the emission unit is composed of the large opening type assist gas nozzle holder, the laser-induced plasma can be observed spectroscopically and the laser process can be monitored. Further, it has a feature that observation of the spatter protection glass is easy.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

2 is a partial side view of the embodiment shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical fiber 2 ... Laser emission port 3 ... Main body 4 ... Single lens 5 ... Cylindrical body 7 ... Connection cylinder 8 ... Funnel-shaped assist gas nozzle 9 ... Protective glass 10 ... Inner nozzle 12 ... Gas flow path 13 Assist gas outlet 16 Gas inlet 31 Holders 31a and 31b First and second blow air outlets 32a and 32b Air inlet

Claims (11)

[Claims] 1. A nozzle portion having a laser emission port that faces a workpiece, a laser emission optical system that emits laser light from the laser emission port, and a laser emission optical system that is located between the laser emission port and the laser emission optical system. There is a passage space through which the laser passes, and a holder having a blow air blowing portion that blows blow air in a direction substantially orthogonal to the laser emission direction in the passage space, and the holder includes the nozzle portion and the laser emission optical system. A laser emission unit, comprising a connection member connected to the side, the connection member opening the periphery of the passage space to the outside. 2. The laser emitting unit according to claim 1, wherein the blow air blowing portion has first and second blow air blowing ports facing the passage space. 3. The laser emitting unit according to claim 2, wherein when the distances between the first and second blow air outlets from the optical system converging point are L1 and L2, respectively. The blow air outlet of 2 is substantially L1:
A laser emission unit, wherein the laser emission units are arranged with a separation distance ratio of L2 = 1: 2. 4. The laser emitting unit according to claim 2 or 3, wherein the first and second blow air outlets have a slit shape with a width of at least 3 mm. 5. A laser emission port that faces a work, a laser emission optical system that emits laser light from the laser emission port, and a laser emission port that is located between the laser emission port and the laser emission optical system. And a holder that defines a passage space. The holder has an assist gas ejection nozzle that ejects an assist gas from the vicinity of the laser emission port toward the work, and the assist gas ejection nozzle is a copper alloy. A laser emission unit comprising: 6. The laser emitting unit according to claim 5, wherein the copper alloy is a copper chromium alloy. 7. The laser emission unit according to claim 1, wherein the laser emission unit has the assist gas ejection nozzle according to claim 5. 8. The laser emission unit according to claim 1, wherein a protective filter that optically protects the laser emission optical system is provided in the passage space. 9. The laser emission unit according to claim 1, wherein the holder has a diameter dimension that allows the laser-induced plasma to be visually spectroscopically observed or laser process monitoring can be performed. Ejection unit. 10. The laser emission unit according to claim 1, wherein the holder is a minimum necessary support column that is provided with the blow air outlet and holds the nozzle portion. unit. 11. The laser emitting unit according to claim 1, wherein the blow air outlet has a slit shape, and a slit-shaped air flow that allows outside air to flow into the passage space along the slit-shaped blow air outlet in the holder. A laser emitting unit having an inlet.