JP4656855B2 - Laser processing head - Google Patents

Description

  The present invention relates to a laser processing head.

  In cutting processing of a metal plate or the like by laser light, a pilot hole through which laser light can pass is provided at the cutting start point of the work material such as sheet metal material, and cutting is started from there, or the end surface of the work material Start cutting from.

  As a method of drilling a pilot hole at the cutting start point, high-power laser light is focused and irradiated on a small area at the cutting start point by a condensing lens built in the laser processing head, and at the same time, an assist gas nozzle coaxial with the laser light assists. A so-called piercing process is performed in which a pilot hole is instantaneously made by injecting gas (oxygen gas) (see, for example, the conventional technique “FIG. 14” described in Patent Document 1).

  The pierced hole by the piercing process described above generally has a larger hole diameter than the pierced hole by other methods, and in particular, in the processing of a thick plate metal, a large amount of molten metal corresponding to the volume of the through hole is formed in a short time. This molten metal adheres around the surface of the pierced hole. For this reason, when shifting to the cutting process, the nozzle tip and the solidified molten metal interfere with each other and the nozzle is damaged, or defective cutting such as burning tends to occur.

In order to solve these problems, when performing the piercing processing of the thick plate as described above, there is an example in which side blowing using air for blowing the molten metal in the horizontal direction from the periphery of the piercing hole is performed (for example, patents) (See FIG. 5 of Document 1).
JP-A-9-206975

  However, as described above, when the molten metal is sprayed from the cutting direction side before the pierced hole so as to pass over the pierced hole along the surface of the workpiece, the molten metal rapidly Cooling may promote adhesion to the surface of the workpiece.

  In order to perform the side blow in the horizontal direction described above, it is desirable to provide a side blow jet outlet in the processing head that can maintain a constant distance between the nozzle and the workpiece. When cutting is performed without using a side blow, there is a problem that the molten metal particles adhere to the injection port or enter the injection port.

  If the side blow is directed toward the center of the pierced hole, the concentration of assist gas (oxygen gas) will be reduced and piercing will not be possible, or the molten metal will blow up more strongly and will adhere to the nozzle or damage the nozzle. Cause it.

  The present invention has been made to solve the above-described problems. The object of the present invention is to provide molten metal that scatters on the surface of a workpiece during piercing processing, particularly when processing a thick plate metal, around the piercing hole. An object of the present invention is to provide a laser processing head which prevents adhesion and prevents adhesion to a nozzle opening and a side blow outlet.

The laser processing head according to claim 1, as means for solving the above-described problem, includes a laser condensing optical system and a nozzle that ejects an assist gas coaxially with the optical axis of the laser condensing optical system. In the processing head, the laser processing head is provided with a side blow gas jet port for jetting side blow gas in the direction of the surface of the workpiece, and an angle for changing the direction of the side blow gas flow jetted from the side blow gas jet port A variable side blow gas impingement plate is provided, and an intersection position (P) between the stream line (FL) of the side blow gas flow and the optical axis is in a range of −10 mm to 20 mm from the surface of the workpiece. The molten metal particles scattered above the workpiece are cooled and solidified by the side blow gas flow, and the side blow gas collision plate is The gist of the invention is that it has a protective function of preventing entry into the id blow gas outlet .

  According to the present invention, it is possible to prevent a large amount of molten metal scattered on the surface of a workpiece during piercing processing, particularly during piercing processing of a thick plate metal, from adhering around the piercing hole.

  Thereby, when it transfers to a cutting process from a piercing process, it can prevent that a nozzle front-end | tip and the solidified molten metal interfere, and a nozzle is damaged or defective cuttings, such as burning, arise.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an explanatory view of a laser processing head according to the present invention. In FIG. 1, for example, a condensing lens or a concave mirror is provided inside the laser processing head 1 as an optical system for condensing laser light (not shown), and from a laser light source (not shown) such as a carbon dioxide laser. The laser beam can be condensed on the surface of the workpiece W.

  Further, an assist gas injection nozzle 3 having an injection port for injecting an assist gas such as oxygen gas to the laser processing portion is provided at the lower end of the laser processing head 1. The injection port of the assist gas injection nozzle 3 is provided coaxially with the optical axis O of the optical system for condensing the laser light, and is provided so that the laser light LB condensed with the assist gas can pass therethrough.

  A side blow gas collision plate support 5 that hangs down in the direction of the workpiece W is provided on the side of the laser processing head 1, and a side blow gas collision plate 7 is provided on the side blow gas collision plate support 5. With respect to the surface of the workpiece W, it is provided so as to be able to rotate and rotate about a pivot 9 supported on the side blow gas collision plate support 5.

  The angle adjustment range of the side blow gas collision plate 7 is such that the angle θ formed by the surface of the side blow gas collision plate 7 and the surface of the workpiece W can be adjusted in a range of 0 degrees to 45 degrees. It is provided.

  The laser processing head 1 above the side blow gas impingement plate 7 is provided with a side blow gas SG outlet 11, which is connected to a side blow gas SG (not shown) via a conduit 13. Connected to the source. For the side blow gas SG, air having a pressure of 0.1 to 0.5 MPa or assist gas is used.

  The above-described explanatory view of FIG. 1 shows a view in which the workpiece W is pierced, and the side blow gas SG ejected from the ejection port 11 has an inclination angle θ of 0 degree or more and less than 45 degrees. 1 collides with the side blow gas collision plate 7 adjusted to the range, and flows to the right obliquely downward in FIG. 1, and the streamline FL of the side blow gas SG at this time and the light of the condenser lens The crossing position P with the axis O is adjusted so as to cross the upper part H of the surface of the workpiece W. The intersection position P is adjusted to an appropriate value within a range of -10 mm to 20 mm in height (H) from the workpiece surface. In addition, the height is based on the surface of the workpiece W, and “+” is defined above the surface and “−” is directed toward the bottom surface.

  When the above-mentioned intersection position P is adjusted to an appropriate value (H> 0 in FIG. 1) within the range of −10 mm to 20 mm, the molten metal particles 15 scattered upward from the workpiece W become side blow gas. Due to the flow of SG, the workpiece W is cooled along with the flow FL of the side blow gas SG above the workpiece W, and is cooled and solidified as metal particles that fall onto the surface of the workpiece W. Hardly adheres.

  Further, FIG. 2 shows a state where the piercing process has progressed. As shown in FIG. 2, the molten metal particles 15 scattered above the workpiece W during the piercing process are cooled along with the flow FL of the side blow gas SG and simultaneously cooled and solidified as metal particles. Although it falls on the surface of the workpiece W, it grows around the piercing hole 17 so that the molten metal 15 ′ that retains fluidity without being cooled by the side blow gas SG rises in a ring shape. To do.

  FIG. 3 shows a state in which the piercing process has further progressed and the piercing hole 17 has penetrated. As shown in FIG. 3, when the piercing hole 17 penetrates, the molten metal 15 ′ is drawn into the piercing hole 17 by the assist gas passing through the piercing hole 17, and falls downward. As shown, in the state where the piercing process is completed, the surface of the workpiece W remains only as a foil-like deposit 15 ″ attached in the form of a foil.

  The side blow gas impingement plate 7 prevents the molten metal particles (sputter) generated during processing from entering the ejection port 11 even if the side blow is stopped at the time of piercing or normal cutting without using the side blow. It also plays a protective function to prevent it.

  Further, the side blow gas SG ejected from the ejection port 11 collides with the side blow gas collision plate 7 whose inclination angle θ is adjusted to a range of 0 degree or more and less than 45 degrees, and in FIG. When flowing, the air 19 is drawn in and flows out from behind the side blow gas collision plate 7 (left side in FIG. 1), so that the flow rate of the side blow is increased to enhance the effect of blowing molten metal.

  In addition, since the back side (left side in FIG. 1) of the side blow gas collision plate 7 is open, even if molten metal particles (sputter) enter the gap between the side blow gas collision plate 7 and the jet port 11 There is also a merit that it does not pass through the back and deposit on the spout 11.

  The pressure (or flow rate) of the side blow gas SG is provided so as to be controlled and adjusted by a known numerical control device or manually, and the on / off timing of the side blow gas SG can be similarly controlled by the numerical control device. It is like that.

  As a result, it is possible to enhance the side blow gas SG ejection effect while monitoring the machining state. In addition, by controlling the on / off timing of the side blow gas SG with a numerical control device, for example, the supply of the side blow gas SG can be delayed in order to concentrate the assist gas at the piercing point at the start of piercing. Is possible.

Explanatory drawing of the laser processing head which concerns on this invention. Explanatory drawing of the state which the piercing process advanced from the state of FIG. Explanatory drawing of the state which the piercing hole penetrated from the state of FIG. 2, and the piercing hole penetrated. Explanatory drawing of the state which completed the piercing process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser processing head 3 Assist gas injection nozzle 5 Side blow gas collision board support body 7 Side blow gas collision board 9 Axis 11 Side blow gas SG outlet 13 Pipe line 15 Molten metal particle 15 'Molten metal 15 which maintained fluidity ”Foil-like deposit 17 Pierce hole 19 Air FL Stream line of side blow gas SG O Optical axis P Crossing position of stream line FL and optical axis O of condenser lens SG Side blow gas W Work material

Claims (1)

In a laser processing head comprising a laser focusing optical system and a nozzle for injecting an assist gas coaxially with the optical axis of the laser focusing optical system, a side blow gas is applied to the laser processing head toward the surface of the workpiece. And a side blow gas impingement plate of variable angle for changing the direction of the side blow gas flow ejected from the side blow gas jet port, and a streamline of the side blow gas flow ( FL) and the optical axis crossing position (P) can be adjusted so as to be in a range of −10 mm to 20 mm from the surface of the workpiece, and the molten metal particles scattered above the workpiece are It is cooled and solidified by the side blow gas flow, and the side blow gas impingement plate performs a protective function to prevent entry into the side blow gas jet port. A featured laser processing head.

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