JP2011189362A - Apparatus and method of laser machining - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser machining apparatus and a laser machining method capable of improving the machining efficiency by suppressing the effect of objects to be removed on the laser beam machining without using any assist gas or liquid. <P>SOLUTION: The laser machining apparatus for machining a workpiece W by applying laser beam thereto includes: a first laser beam applying mechanism 2 for converging the laser beam L1 at the intensity of the laser beam capable of machining the workpiece W, and applying the first laser beam to a machining surface of the workpiece W; and a second laser beam applying mechanism 3 for converging the second laser beam L2 at the intensity of the laser beam by which the workpiece W is not machined, and applying the second laser beam to the periphery of a machining point by the first laser beam L1 simultaneously with the first laser beam L1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing method suitable for processing ultra-hard materials, for example.

  In general, a mechanical method such as grinding with a grindstone is used to shape a member or a tool using an ultra-hard material such as a cubic boron nitride sintered body (hereinafter referred to as a CBN sintered body) or a diamond sintered body. The shaping is done. However, CBN sintered bodies and diamond sintered bodies are mechanically strong, and it has been difficult to perform micron-order precision processing with a grindstone that deforms with each processing.

  Also known is a method of performing processing such as cutting by irradiating a member having a surface made of a CBN sintered body or a diamond sintered body with a laser beam and repeatedly scanning in order to obtain desired processing properties. Yes. In this method, when the next laser beam is scanned due to the deposition of a work removal material such as a melt generated by the laser light irradiation, the laser light is inhibited and absorbed by the deposited work removal material and processed. The speed was reduced, and efficient and precise surface processing was difficult.

  For this reason, conventionally, as a method for preventing the accumulation of the processed removed material, a method of blowing the processed removed material with an assist gas or a method of processing while removing the processed removed material by suction or the like is used. A method of spraying water at a high pressure has also been proposed. In this method, the processed part is cooled by spraying water at a high pressure, but it is considered that the processed removal can also be blown away. Patent Document 2 proposes a technique of storing a liquid such as distilled water in a processing housing in which a workpiece is held and irradiating the workpiece with laser light through the liquid. In this method, the processing housing is formed of a transparent plate of transparent glass or transparent resin in order to transmit laser light.

JP 2006-96051 A JP 2009-66657 A

The following problems remain in the conventional technology.
In other words, it is difficult to blow off or suck all the processed removed material by the conventional processing method using the assist gas or the method of removing the processed removed material by suction, and the conventional method of spraying water has a high water pressure. There is a disadvantage that the optical system of the laser beam is contaminated by high rebound. In the technique described in Patent Document 2, since the liquid is accommodated in the processing housing, laser light is incident from the outside of the processing housing through the processing housing. Therefore, the processing housing is formed of a transparent plate. However, there is a problem that the laser beam is attenuated during transmission and the processing housing itself is damaged by the laser beam.

  The present invention has been made in view of the above-described problems. A laser processing apparatus and a laser processing method capable of suppressing the influence of a processed removal product on laser processing without using an assist gas or a liquid and improving processing efficiency. The purpose is to provide.

  The present invention employs the following configuration in order to solve the above problems. That is, the laser processing apparatus of the present invention is an apparatus that irradiates a processing target with laser light and processes the first laser light to a laser beam intensity that can be processed by the processing target. A first laser beam irradiation mechanism for irradiating a processing surface of a processing object; and a second laser beam that is focused on a laser beam intensity at which the processing object is not processed and simultaneously with the first laser beam. And a second laser beam irradiation mechanism for irradiating around the processing point by the laser beam.

  Further, the laser processing method of the present invention is a method of processing by irradiating a processing target with laser light, and the first laser light is condensed to a laser beam intensity that can be processed by the processing target. A first laser beam irradiation step for irradiating the processing surface of the processing object; and the second laser beam is focused on a laser beam intensity at which the processing object is not processed, and simultaneously with the first laser beam. And a second laser beam irradiation step of irradiating around the processing point by the laser beam.

  In these laser processing apparatuses and laser processing methods, the second laser beam is condensed to a laser beam intensity at which the workpiece is not processed, and simultaneously with the first laser beam, around the processing point by the first laser beam. Since the irradiation is performed, the processing removal object in the vicinity of the processing point is excited and subdivided by the second laser beam, thereby suppressing the influence of the processing removal object and improving the processing efficiency. That is, conventionally, the energy of the laser beam originally used for processing has been absorbed by the processed removal material generated in the vicinity of the processing point, but in the present invention, separately from the first laser beam that becomes the processing beam. By exciting and subdividing the processed removal object in the vicinity of the processing point with the second laser light that becomes the processed removal object excitation beam with the laser light intensity lowered, the energy absorption of the first laser light by the processed removal object is reduced. Can be suppressed.

  Further, in the laser processing apparatus of the present invention, the first laser light irradiation mechanism irradiates the first laser light from the vertical direction side with respect to the processing surface of the processing object, and the second laser light. The irradiation mechanism irradiates the second laser light from the horizontal direction side with respect to the processing surface of the processing object.

  That is, in this laser processing apparatus, the first laser beam is irradiated from the vertical direction side with respect to the processing surface of the processing object, and the second laser light is irradiated from the horizontal direction side with respect to the processing surface of the processing object. Therefore, the first laser beam directly responsible for processing can be efficiently condensed from the vertical side, which is the front side of the processing surface, to the diffraction limit, and the second laser beam is on the side of the processing surface. Light is gradually condensed from the horizontal direction, and the periphery of the processing point can be excited and heated with a wide irradiation area. In particular, when the second laser beam is obliquely irradiated onto the processing surface from the horizontal direction side, the processing surface of the workpiece can be excited and heated by the second laser beam, and the first laser beam Can be made more efficient.

The present invention has the following effects.
That is, according to the laser processing apparatus and the laser processing method according to the present invention, the second laser beam is focused on the laser beam intensity at which the workpiece is not processed, and the first laser beam is simultaneously formed with the first laser beam. Since the periphery of the machining point is irradiated with the second laser beam, the processing removal object near the processing point is excited and subdivided by the second laser beam, so that the influence of the processing removal object can be suppressed and the processing efficiency can be improved. it can. This enables high-quality and high-efficiency processing even in cutting or grinding of brittle materials and ceramics that are difficult to process.

1 is a simple overall configuration diagram showing a laser processing apparatus in an embodiment of a laser processing apparatus and a laser processing method according to the present invention. In this embodiment, it is a perspective view of the principal part which shows irradiation of the 1st laser beam and 2nd laser beam with respect to a workpiece. In this embodiment, it is explanatory drawing which shows irradiation of the 1st laser beam and 2nd laser beam with respect to a workpiece. An enlarged image by an electron microscope showing a groove (a) actually laser processed by the embodiment of the laser processing apparatus and laser processing method according to the present invention and a groove (b) laser processed only by the first laser beam ( It is an image viewed from a 45 ° oblique direction with respect to the processing surface).

  Hereinafter, an embodiment of a laser processing apparatus and a laser processing method according to the present invention will be described with reference to FIGS. 1 to 3.

  As shown in FIGS. 1 to 3, the laser processing apparatus 1 of the present embodiment is an apparatus that processes a workpiece W by irradiating the workpiece W with laser light, and the workpiece W is used to process the first laser beam L1. The first laser beam irradiation mechanism 2 that focuses the laser beam intensity that can be processed and irradiates the processing surface of the workpiece W, and the second laser beam L2 is collected to the laser beam intensity that the workpiece W is not processed. A second laser beam irradiation mechanism 3 that irradiates and irradiates around the processing point P by the first laser beam L1 simultaneously with the first laser beam L1, and a moving mechanism that can move while holding the workpiece W 4 and a control unit 5 for controlling them.

  The workpiece W is, for example, a substrate, a cutting tool, or a mold, and a substrate such as a SiC substrate, or a surface to be processed is formed into a film by a sintered diamond sintered body, a CBN sintered body, or vapor phase synthesis. It is composed of a diamond film or the like.

  The moving mechanism 4 includes an X-axis stage portion 4x that can move in the X direction parallel to the horizontal plane, and a moving direction in the Y direction that is provided on the X-axis stage portion 4x and that is perpendicular to the X direction and parallel to the horizontal plane. A Y-axis stage unit 4y and a Z-axis stage unit 4z provided on the Y-axis stage unit 4y and capable of holding the workpiece W and movable in a direction perpendicular to the horizontal plane.

The first laser light irradiation mechanism 2 includes a first laser light source 6A that oscillates the first laser light L1 in response to a trigger signal of a Q switch, and the first laser light L1 from the first laser light source 6A. A first optical system 7A that collects light in a spot shape and a CCD camera 8 that captures an image to confirm the processing position of the held processing target W are provided. The first optical system 7A is also provided with a galvano scanner that scans the first laser light L1 to be irradiated.
The first laser beam irradiation mechanism 2 is installed above the moving mechanism 4 so that the first laser beam L1 can be irradiated from the vertical direction side with respect to the processing surface of the workpiece W.
The first laser beam L1 is set so as to be able to irradiate vertically or substantially perpendicularly at an angle θ2 of 75 to 90 ° with respect to the processing surface of the workpiece W.

  The second laser light irradiation mechanism 3 includes a second laser light source 6B that oscillates the second laser light L2 in response to a trigger signal of a Q switch, and a second laser light L2 from the second laser light source 6B. And a second optical system 7B that collects light more slowly than the first laser light L1. That is, in the second optical system 7B, the focal point of the second laser light L2 is set farther than the processing point P by the first laser light L1, and the vicinity of the processing point P is irradiated over a wide area with a wide irradiation area. Is set to

The second laser light irradiation mechanism 3 is installed on the side of the moving mechanism 4 so as to be able to irradiate the second laser light L2 with respect to the processing surface of the workpiece W from the horizontal direction side.
The second laser beam L2 is set so as to be able to irradiate horizontally or substantially horizontally at an angle θ2 of 0 to 15 ° with respect to the processing surface of the processing object W.

  The first laser light source 6A and the second laser light source 6B can use laser light with a wavelength of 190 to 550 nm, and laser light sources that emit laser light with a wavelength of 266 nm or less are particularly preferable. For example, in the present embodiment, a laser light source that oscillates laser light having a wavelength of 262 nm is used.

As shown in FIG. 2, the first optical system 7 </ b> A condenses the first laser light L <b> 1 that is circularly polarized and the polarizing plate 9 that makes the linearly polarized first laser light L <b> 1 circularly polarized. Objective lens 10.
The polarizing plate 9 is a λ / 4 plate provided with a anti-reflection coating for the wavelength of the first laser beam L1.
The objective lens 10 is provided with a anti-reflection coating for the wavelength of the first laser beam L1.
The CCD camera 8 is installed adjacent to the first optical system 7A.

The second optical system 7B includes a power density adjusting lens 11 that condenses the second laser light L2 and adjusts the power density to be irradiated.
The power density adjusting lens 11 is provided with a anti-reflection coating for the wavelength of the second laser light L2.
Note that a suction nozzle (not shown) for sucking the generated work removal material is disposed above the moving mechanism 4.

  As described above, in the laser processing apparatus 1 of the present embodiment, the second laser light L2 is focused on the laser light intensity at which the workpiece W is not processed, and simultaneously with the first laser light L1, the first laser light L1. As shown in FIG. 3, the processing removal object D in the vicinity of the processing point P is excited and subdivided by the second laser beam L 2, so that the influence of the processing removal object D is produced. Can be suppressed and the processing efficiency can be improved.

  That is, conventionally, the energy of the laser beam originally used for processing has been absorbed by the processed removal D generated in the vicinity of the processing point P. However, in the present embodiment, the first laser beam that becomes the processing beam is used. Separately from L1, the second removed laser beam L2 that is a processing removed object excitation beam with a lowered laser beam intensity is used to excite and subdivide the processing removed object D in the vicinity of the processing point P. Energy absorption of one laser beam L1 can be suppressed.

  In addition, since the processed removal object D irradiated with the second laser beam L2 is excited and is in a high energy state, it changes to an ionic state when in a vapor state, and via a vapor state when in a liquid state. Changes to the ionic state. Therefore, the ionized workpiece D can be easily sucked and removed by the suction nozzle.

  In addition, the first laser beam L1 is irradiated from the vertical direction side with respect to the processing surface of the workpiece W, and the second laser beam L2 is irradiated from the horizontal direction side with respect to the processing surface of the workpiece W. The first laser beam L1 responsible for direct machining can be efficiently condensed from the vertical direction side, which is the front side of the machining surface, to the diffraction limit, and the second laser beam L2 is on the side of the machining surface. It is possible to excite and heat the periphery of the processing point P with a wide irradiation area by being gradually condensed from the horizontal direction side. In particular, when the second laser beam L2 is obliquely irradiated to the processing surface from the horizontal direction side, the processing surface of the workpiece W can also be excited and heated by the second laser beam L2, and the first The processing with the laser beam L1 can be made more efficient.

The results of actually processing and evaluating the object to be processed by the laser processing apparatus and laser processing method of the above embodiment are shown below.
In addition, the α-Al ₂ O ₃ sintered body was grooved as a processing object, and the processed surface was observed with an electron microscope. Further, as a comparative example, the processed surface was also observed in the case where the groove processing was performed by irradiating only the first laser beam. The electron micrograph of the processed surface by these groove processing is shown in FIG.

  As can be seen from this image, on the processed surface of the comparative example (FIG. 4B) in which only the first laser beam was irradiated to perform the groove processing, the processed removal material was deposited around the processing groove. On the other hand, in the processed surface (FIG. 4 (a)) of this embodiment, the first laser beam from the substantially vertical direction and the second laser beam from the substantially horizontal direction are simultaneously irradiated to form the groove. There is almost no processed removal around the processed groove, and a clean processed groove is obtained.

  The technical scope of the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above embodiment, a laser light source is provided separately for the first laser light irradiation mechanism and the second laser light irradiation mechanism, but one laser light source is shared and one laser beam emitted from this laser light source is used. One laser beam may be divided into two laser beams by an optical system and used as the first laser beam and the second laser beam.

  The laser processing apparatus and laser processing method of the present invention are particularly suitable for processing such as cutting and grinding of brittle materials and ceramics that are difficult to process.

  DESCRIPTION OF SYMBOLS 1 ... Laser processing apparatus, 2 ... 1st laser beam irradiation mechanism, 3 ... 2nd laser beam irradiation mechanism, 4 ... Movement mechanism, 7A ... 1st optical system, 7B ... 2nd optical system, L1 ... 1st 1 laser beam, L2 ... second laser beam, W ... work object

Claims (3)

An apparatus for irradiating a processing object with laser light,
A first laser beam irradiation mechanism for focusing the first laser beam on a laser beam intensity that can be processed by the processing object and irradiating the processing surface of the processing object;
A second laser light irradiation mechanism for condensing the second laser light to a laser light intensity at which the workpiece is not processed and irradiating around the processing point by the first laser light simultaneously with the first laser light And a laser processing apparatus. In the laser processing apparatus of Claim 1,
The first laser light irradiation mechanism irradiates the first laser light from the side perpendicular to the processing surface of the processing object,
The laser processing apparatus, wherein the second laser light irradiation mechanism irradiates the second laser light from a horizontal side with respect to a processing surface of the processing object. A method of processing by irradiating a processing object with laser light,
A first laser beam irradiation step of condensing the first laser beam to a laser beam intensity that can be processed by the workpiece and irradiating the processing surface of the workpiece;
A second laser beam irradiation step of condensing the second laser beam to a laser beam intensity at which the workpiece is not processed and irradiating around the processing point by the first laser beam simultaneously with the first laser beam. And a laser processing method characterized by comprising: