JP5194367B2 - Laser processing head and laser processing method - Google Patents

Description

  The present invention relates to a laser processing head used for laser processing represented by laser welding, for example, to a laser processing head and a laser processing method for preventing spatter adhesion to a laser optical system when laser welding is performed.

  In the processing head for laser welding, a protective glass is provided between the condenser lens at the end of the laser optical system and the work piece, and the air flow substantially parallel to the work piece is closer to the work piece than the protective glass. Is formed so as to provide a so-called air shutter function to protect the condensing lens and the protective glass from spatter adhesion. However, not all spatter can be blown away with the air shutter, and some spatter passes through the air shutter and adheres to the protective glass, thus preventing deterioration in welding quality due to a decrease in laser output at the welding position. For this reason, it is necessary to periodically replace the protective glass, resulting in a decrease in productivity. In particular, welding of galvanized steel sheets and aluminum alloys involves a large amount of spatter generation, so the frequency of replacement of the protective glass is high, and the productivity is significantly reduced.

Therefore, as described in Patent Document 1, for example, the air shutter is a first air shutter, and a second air shutter that is directed obliquely downward so as to intersect the first air shutter is a first air shutter. There has been proposed a technique that is provided between the shutter and the protective glass and prevents spatter adhesion to the protective glass by the synergistic effect of the two air shutters.
JP-A-2005-219108

  In the technique described in Patent Document 1, although the amount of spatter adhering to the protective glass is reduced by the synergistic effect of the two air shutters, the spatter once adhering to the protective glass cannot be removed. In order to prevent deterioration of the welding quality due to the adhesion of the protective glass, the replacement frequency of the protective glass must be increased.

  In view of the above problems, the present invention provides a laser processing head and a laser processing method capable of preventing spatter generated by laser processing from adhering to protective glass and removing spatter once adhering to protective glass. The purpose is to do.

The invention described in claim 1 is based on the premise that the laser processing head performs laser processing by condensing laser light with a condensing lens at the end of the laser optical system and irradiating the workpiece with laser processing. A protective glass disposed on the workpiece side with respect to the optical lens; a first air nozzle disposed on the workpiece side with respect to the protective glass and forming an air flow substantially parallel to the workpiece; and the protective glass. And a second air nozzle that is disposed between the first air nozzle and that forms a flow of air from the side of the laser light path toward the protective glass.
Then, the flow of air in which the second air nozzle is formed so as to direct the sites offset in the flow direction downstream side of the air first air nozzle is formed from a center of the protective glass of the protective glass, the second It is characterized in that the direction of the air nozzle is set.

  Therefore, in the first aspect of the present invention, the spatter generated during the laser processing is removed by the air flow formed by the first air nozzle so as to be blown away, and the first air nozzle is formed. It is possible to blow away a part of the sputters adhering to the protective glass without being blown away by the air flow with the air flow formed by the second air nozzle.

The invention described in claim 5 is the laser processing method according to the invention described in claim 1, in which the laser beam is collected by a condenser lens at the end of the laser optical system and protected. Assuming that laser processing is performed by transmitting the glass and irradiating the workpiece, the protective glass is disposed on the workpiece side of the condenser lens, and the workpiece side of the protective glass. A first air nozzle that forms an air flow substantially parallel to the workpiece, and further, an air flow from the side of the laser beam path toward the protective glass between the protective glass and the first air nozzle. A second air nozzle is formed to form The air flow from the first air nozzle forms a layered air flow substantially parallel to the workpiece that functions as an air shutter on the workpiece side with respect to the protective glass, and the second air nozzle is formed. Directing the flow of air to a portion of the protective glass that is offset from the center of the protective glass to the downstream side in the air flow direction formed by the first air nozzle, and irradiating the workpiece with laser light in this state It is characterized by.

Therefore, in the invention described in claim 5, the spatter generated during laser processing is removed by being blown away by the air flow that functions as the air shutter, and the air flow that functions as the air shutter. It becomes possible to blow away a part of the sputters adhering to the protective glass without being blown away by the air blow.

According to the first and fifth aspects of the invention, in addition to the function of the conventional so-called air shutter, air is blown onto the protective glass, so that it is possible to remove the spatter once adhered to the protective glass. This reduces laser output quality at the processing point due to spatter adhesion to the protective glass and improves laser processing quality. It also reduces man-hours and productivity by reducing the replacement frequency of the protective glass. it can.

In particular, since laser processing is performed while blowing so-called air toward the protective glass , it is possible to immediately remove the spatter adhering to the protective glass by air blow, so that the spatter is effectively applied before the spatter is fixed on the protective glass. Can be removed.

  FIG. 1 shows the structure of the main part of a laser welding head as a more specific embodiment of the present invention.

  In FIG. 1, W is a workpiece to be worked as a flat plate-like workpiece such as a steel plate, and 1 is a laser welding head as a laser machining head.

  A laser beam L is introduced into the housing 2 of the laser welding head 1 and a condenser lens 3 which forms a laser optical system together with a reflection mirror (not shown) is accommodated. A protective glass 4 for protecting the condenser lens 3 is disposed on the workpiece W side of the condenser lens 3 as shown in FIG. 1, and a laser beam L output from a laser oscillator (not shown). Is condensed by the condensing lens 3, then passes through the protective glass 4 and is irradiated to the welded part P of the workpiece W.

  Also, a pair of air blow nozzles 5 are arranged as second air nozzles on the side of the laser light path so that they are opposed to each other with the optical axis La of the laser light L sandwiched between the protective glass 4 and the workpiece W side. In addition, a flat air nozzle 7 serving as a first air nozzle is attached below the air blow nozzle 5, that is, on the workpiece W side via a protective cylinder 6.

Each air blow nozzle 5 forms air flow toward the protective glass 4 by blowing air in the directions of arrows A and B directed obliquely upward, while the flat air nozzle 7 stratifies the air in the direction of arrow C. By blowing out, a flow of air parallel to the workpiece W is formed, and the function as an air shutter is exhibited. More specifically, each air blow nozzle 5 blows out air from the center of the protective glass 4 toward the downstream side in the direction of arrow C, that is, downstream of the air flow direction formed by the flat air nozzle 7 as described later. together becomes, the air blow nozzle 5 is disposed immediately below the said protective glass 4 to the protective glass 4.

  A disk-shaped protective plate 9 is attached below the flat air nozzle 7, that is, on the workpiece W side via a bracket 8, and an optical path hole 9 a through which the laser light L passes is formed through the protective plate 9. Yes.

  In the laser welding head 1 configured as described above, the laser light L is collected by the condenser lens 3 and then transmitted through the protective glass 4 to irradiate the welded part P of the workpiece W, for example, a laser. Laser welding is performed by moving the welding head 1 relative to the workpiece W. At the same time, each air blow nozzle 5 blows air toward the protective glass 4 so as to be directed obliquely upward from the lower side of the protective glass 4, and blows air from the flat air nozzle 7 to air that functions as an air shutter. Form a flow.

  As the welding operation proceeds, spatter scatters from the welded part P, and a part of the spatter deviating from the optical path of the laser beam L adheres to the protective plate 9 and is removed while directing the optical path direction of the laser beam L. The spatter scattered while passing through the optical path hole 9 a of the protective plate 9 enters the protective cylinder 6. Some of the spatter that has entered the protective cylinder 6 is removed by blowing the air flow formed by the flat air nozzle 7 in the air flow direction by functioning as an air shutter. Under the influence of the flow of air that functions as a shutter, it reaches the protective glass 4 while deflecting the scattering direction. Moreover, since the sputter | spatter which reached | attained the protection glass 4 is cooled by the air which the flat air nozzle 7 blows off, when it collides with the protection glass 4, it will bounce down below, but the part which reached the protection glass 4 not fully cooled The sputter adheres to the protective glass 4.

  FIG. 2 is an enlarged view showing the air blow nozzle in FIG.

  Here, since the sputter reaches the protective glass 4 while being affected by the air blown from the flat air nozzle 7 as described above, the flat air nozzle 7 is formed from the center of the protective glass 4 as shown in FIG. Spatter is concentrated on the portion S that is offset downstream in the air flow direction. Therefore, the sputter | spatter adhering to the protective glass 4 is blown off by air-blowing in each air blow nozzle 5 toward the site | part S offset from the center to the downstream of the flow direction of the air which the flat air nozzle 7 forms among the protective glass 4. Thus, it is effectively removed. Moreover, since each air blow nozzle 5 is arrange | positioned directly under the protective glass 4, the sputter | spatter adhering to the protective glass 4 can be removed more effectively. Furthermore, by causing each air blow nozzle 5 to flow air into the protective cylinder 6, it also has a function of preventing the generation of negative pressure in the protective cylinder 6 due to the air blown out by the flat air nozzle 7.

  Therefore, according to the present embodiment, a part of spatter generated during welding is removed by being blown away by the air flow functioning as an air shutter formed by the flat air nozzle 7, and the remaining spatter is removed. Even if it once adheres to the surface of the protective glass 4, it is possible to blow off the spatter attached to the surface of the protective glass 4 by air blowing with each air blow nozzle 5. As a result, the original function of the protective glass 4 can be maintained over a long period of time, and the replacement frequency of the protective glass 4 can be lowered to improve productivity.

  Although the present embodiment has been described by taking laser welding as an example, it goes without saying that the present invention can be applied to various types of laser processing other than laser welding.

  FIG. 3 shows a modification of the air blow nozzle in FIG. 1 as the second embodiment of the present invention, and FIG. 4 is a plan view showing the air blow nozzle and the flat air nozzle in FIG. 3 and 4, the same reference numerals are given to the same or corresponding parts as in FIG. 1.

  In the second embodiment shown in FIG. 3, the air blow nozzle 5 is formed as a single unit, and the air blow nozzle 5 is formed when viewed along the optical axis La of the laser light L as shown in FIG. The air flow direction is the same as the air flow direction formed by the flat air nozzle 7.

  In the second embodiment, in addition to the effects of the first embodiment, spattering toward the protective glass 4 is protected while deflecting the scattering direction due to the influence of the air flow formed by the flat air nozzle 7. Since the scattering direction is further deflected by the air flow formed by the air blow nozzle 5 before reaching the glass 4, the spatter adherence to the portion of the protective glass 4 through which the laser light L is transmitted is more effectively suppressed. There are merits that can be done.

The figure which shows the structure of the principal part of a laser welding head as more concrete embodiment of this invention. The enlarged view of the air blow nozzle in FIG. The figure which shows the modification of the air blow nozzle in FIG. 1 as the 2nd Embodiment of this invention. The top view which shows the air blow nozzle and flat air nozzle in FIG.

Explanation of symbols

1. Laser welding head (laser machining head)
3 ... Condensing lens 4 ... Protective glass 5 ... Air blow nozzle (second air nozzle)
7. Flat air nozzle (first air nozzle)
9 ... Protection plate 9a ... Optical path hole W ... Workpiece (workpiece)
L ... Laser light

Claims (6)

A laser processing head that performs laser processing by irradiating a workpiece after condensing laser light with a condensing lens at the end of a laser optical system,
Protective glass placed on the workpiece side of the condenser lens,
A first air nozzle that is disposed closer to the workpiece than the protective glass and forms a flow of air substantially parallel to the workpiece;
A second air nozzle disposed between the protective glass and the first air nozzle, forming a flow of air from the side of the laser light path toward the protective glass;
With
Air flow which the second air nozzle is formed, from the center of the protective glass of the protective glass to direct sites offset in the flow direction downstream side of the air first air nozzle is formed, the second air nozzle A laser processing head characterized in that a direction is set. The second air nozzle is arranged directly below the protective glass with respect to the protective glass,
The laser processing head according to claim 1, wherein the second air nozzle blows air toward the protective glass with a flow of air directed obliquely upward from below the protective glass.   2. The air flow direction formed by the second air nozzle coincides with the air flow direction formed by the first air nozzle when viewed along the optical axis direction of the laser beam. Or the laser processing head of 2.   The laser processing according to any one of claims 1 to 3, wherein a protective plate through which an optical path hole through which laser light passes is formed is disposed closer to the workpiece than the first air nozzle. head. A method of performing laser processing by condensing laser light with a condensing lens at the end of a laser optical system and then irradiating a workpiece through a protective glass,
While placing protective glass on the workpiece side than the condenser lens,
A first air nozzle that forms a flow of air substantially parallel to the workpiece on the workpiece side relative to the protective glass;
Furthermore, between the protective glass and the first air nozzle, a second air nozzle that forms an air flow from the side of the laser optical path toward the protective glass is disposed,
With the air flow from the first air nozzle, a laminar air flow substantially parallel to the workpiece that functions as an air shutter is formed on the workpiece side of the protective glass,
The flow of air the second air nozzle is formed, is directed to sites offset from the center of the protective glass in the flow direction downstream side of the air first air nozzle is formed of the protective glass,
A laser processing method characterized by irradiating a workpiece with laser light in this state. The second air nozzle is arranged directly below the protective glass with respect to the protective glass,
6. The laser processing method according to claim 5, wherein the second air nozzle blows air toward the protective glass with a flow of air directed obliquely upward from below the protective glass.

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