JP2007290024A - Laser beam machining apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus in which a support shaft is heated by a beam situated outside of the laser beam, which does not contribute to machining among laser beams and lowering of scanning characteristic of a mirror is prevented. <P>SOLUTION: A laser beam machining apparatus 1 of a galvano scanning system is equipped with, as shown in figures, a laser beam source 10 for emitting a laser beam L1, a beam expander 20 that expands the laser beam L1 to emit a laser beam L2, a galvano mirror device 30 that turns a mirror 31 to perform optical scanning, and a focusing lens 40. Between the beam expander 20 and the mirror 31, there is arranged a shielding member 35 that prevents a support shaft 33 from being irradiated with the beam L2B situated on the outer side of the laser beam L2A among the laser beams L2. As a result, the support shaft 33 is heated and the scanning characteristic of the mirror 31 is prevented from lowering. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a galvano scanning laser processing apparatus.

As a general structure of a laser processing apparatus, the one described in Patent Document 1 below is known. This includes a laser oscillator having a beam expander that expands a laser beam emitted from a laser light source to generate a laser beam having a predetermined diameter, and an optical axis of the laser beam emitted from the beam expander. A first galvano scanner having a scanner rotation axis arranged to be inclined about the optical axis of the laser beam with respect to the reference plane, and a second galvano for reflecting the laser beam emitted from the first galvano scanner toward the converging lens. And a scanner. The first galvano scanner includes a mirror that reflects the laser beam emitted from the beam expander, a motor for driving the mirror, and a support shaft for assembling the mirror to the rotation shaft of the motor.
JP 2002-107652 A

In general, in a laser processing apparatus, a laser beam having a beam diameter defined by 1 / e ² (13.5%) of a laser beam diameter emitted from a beam expander is often used. The reason for using a laser beam with a limited beam diameter in this way is to reduce the inertia by reducing the mirror size and reducing the weight, thereby increasing the operating speed. Accordingly, the diameter of the mirror is designed to be approximately the same as or slightly larger than the diameter of the laser beam. However, laser light still exists outside the laser beam, and a connecting portion between the mirror and the support shaft is located on the optical path of the laser light for the same reason as described above. For this reason, the support shaft is irradiated with laser light positioned outside the laser beam, so that the connecting portion between the mirror and the support shaft is affected by thermal expansion or the like, and the scanning characteristics are unstable (mirror resonance point). Fluctuation). The present invention has been completed based on the above situation, and the support shaft body is heated by the laser beam located outside the laser beam emitted from the beam expander, so that the scanning characteristic of the mirror is deteriorated. The purpose is to prevent this.

  As means for achieving the above object, the invention of claim 1 is a laser light source that emits laser light, and a beam expander that has a plurality of lenses and that expands and emits laser light from the laser light source. A mirror for reflecting the laser beam emitted from the beam expander, a motor for driving the mirror, a support shaft for assembling the mirror to the rotation shaft of the motor, and a laser reflected by the mirror A converging lens that converges the beam and irradiates the object to be processed, and the mirror is driven by the motor so that the laser beam emitted from the converging lens is scanned on the object to be processed. A laser processing apparatus for processing the workpiece, wherein the mirror is output from an output side lens of the beam expander. The laser beam is configured to be able to reflect a laser beam having a diameter of a laser beam, and a laser beam positioned outside the laser beam emitted from the beam expander irradiates the support shaft body between the beam expander and the mirror. This is characterized in that a shielding member for preventing this is arranged.

A second aspect of the present invention is the Gaussian profile according to the first aspect, wherein the diameter of the laser beam is measured on a plane perpendicular to the optical axis of the laser light emitted from the beam expander. It is characterized by a beam diameter defined by a beam intensity width of 1 / e ² (13.5%) or more of the peak value of.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the shielding member is located at a position in the vicinity of the support shaft that does not interfere with the mirror when the mirror is driven by the motor. It is characterized by being placed most closely.

  According to a fourth aspect of the present invention, there is provided the apparatus according to any one of the first to third aspects, wherein the shielding member is provided integrally with the motor.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the shielding member has a circular hole having the same diameter as the laser beam emitted from the beam expander, and It is characterized in that a circular hole is arranged coaxially with the laser beam.

<Invention of Claim 1>
According to the first aspect of the present invention, the laser beam positioned outside the laser beam is shielded by the shielding member, and the support shaft body is prevented from being irradiated. As a result, the connecting portion between the mirror and the support shaft body is not affected by thermal expansion or the like, and the scanning characteristics of the mirror can be maintained well.

<Invention of Claim 2>
According to the invention of claim 2, the diameter of the mirror can be made substantially the same as or slightly larger than the beam diameter defined by 1 / e ² . Therefore, the mirror can be reduced in weight, and the inertia of the mirror can be reduced and the operation speed can be increased.

<Invention of Claim 3>
Even if the shielding member is arranged, when the distance between the shielding member and the support shaft is increased, the laser beam located outside the laser beam in the shielding member changes its direction toward the support shaft body due to diffraction, and the support shaft body Irradiated and heated. In that respect, according to the invention of claim 3, the amount of irradiation of the support shaft body by the diffracted laser beam can be reduced.

<Invention of Claim 4>
According to the invention of claim 4, for example, there is no accumulation of mounting errors compared to a configuration in which the motor and the shielding member are separately mounted on a common chassis, so that the positional relationship between the shielding member and the motor can be kept constant. . As a result, since the positional relationship between the shielding member and the mirror can be kept constant with high accuracy, it is possible to reliably prevent the laser beam from being applied to the support shaft. Moreover, since the shielding member and the motor are unitized, handling is easy while maintaining the positional relationship between the two with high accuracy.

<Invention of Claim 5>
According to the fifth aspect of the present invention, it is possible to prevent the laser beam positioned outside the laser beam from being irradiated to the annular region positioned in the outer peripheral portion of the mirror. As a result, the outer peripheral portion of the mirror is heated, and heat can be prevented from being transmitted from here to the connecting portion between the mirror and the support shaft body to cause a thermal influence such as thermal expansion.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIG. 1 or FIG. The laser processing apparatus 1 in the present embodiment is a galvano scanning type laser processing apparatus, and as shown in FIG. 1, a laser light source 10 that emits laser light L1, and a laser light L2 that is expanded from the laser light L1. A beam expander 20 that emits light, a galvanometer mirror device 30 that rotates a mirror 31 to perform optical scanning, and a converging lens 40 are provided. The galvanomirror device 30 is a two-axis galvanometer mirror device composed of an X-axis scanning galvanometer mirror device and a Y-axis scanning galvanometer mirror device (FIGS. 1 and 2 are simplified drawings). Therefore, it is possible to mark a desired character, symbol, figure, or the like on the surface of the workpiece W by rotating each of the mirrors 31 and 31. Has been. In FIGS. 1 and 2, the housing, the control mechanism, and other members are omitted for simplification of the drawings.

The laser light source 10 is, for example, a CO ₂ laser light source, and the laser light L 1 is emitted toward the beam expander 3. The laser light source 10 can be an optical fiber laser light source, a semiconductor laser light source, or the like in addition to the CO ₂ laser light source. The laser light L1 is invisible light, and guide light (not shown) made of visible light is used to indicate the processing position of the laser light L1 in positioning work at the start of processing.

The laser beams L1 and L2 have a substantially circular cross section, and have a beam intensity of 1 / e ² (13.5%) or more of the peak value of the Gaussian profile measured on a plane perpendicular to the optical axis of the laser beam L2. A laser beam having a beam diameter defined by the width is defined as a laser beam L2A, and a laser beam located outside the laser beam L2A in the radial direction of the laser beam L2 is defined as a tail light L2B. In the present embodiment, in order to reduce the weight of the mirror 31 to reduce inertia and increase the operation speed, laser processing is performed using a laser beam L2A having a smaller diameter than the laser beam L2.

  The beam expander 20 includes an incident side lens 21 disposed on the laser light source 10 side and an emission side lens 22 disposed on the galvanomirror device 30 side. The incident-side lens 21 has a concave surface in which the incident-side surface is a horizontal plane orthogonal to the optical axis of the laser light L1 and the emission-side surface is recessed inward. The exit side lens 22 has convex surfaces on both the incident side and the exit side. The laser light L1 emitted from the laser light source 2 is enlarged by passing through the incident side lens 21, and the enlarged laser light passes through the emission side lens 22 and becomes parallel light having a predetermined diameter. It is possible to generate the laser beam L2. Therefore, the distance between the entrance side lens 21 and the exit side lens 22 is set so that the laser beam L2 has a predetermined diameter. The laser beam L2 is emitted from the emission side lens 22 toward the galvanomirror device 30 while maintaining a predetermined diameter.

As shown in FIG. 2, the galvanometer mirror device 30 has a substantially rectangular plate shape, and includes a mirror 31 that reflects the laser beam L <b> 2 </ b> A, a motor 32 for driving the mirror 31, and the mirror 31 assembled to the rotation shaft of the motor 32. And a pedestal 34 to which the motor 32 is fixed.
As shown in FIG. 1, the mirror 31 is installed on the optical path of the laser beam L2A with an angle of inclination θ (approximately 45 ° in FIG. 1) with respect to the reference plane including the optical axis P1 of the laser beam L2A. The laser beam L2 having a beam diameter smaller than the maximum diameter of the emission side lens 22 of the panda 20 is configured to be reflected. The mirror 31 needs to be able to reflect the entire light amount of the laser beam L2A, and to reduce the width of the mirror 31 by reducing the weight of the mirror 31 as much as possible. Therefore, the width dimension R2 of the mirror 31 is substantially the same as or slightly larger than R3 when the diameter dimension of the reflecting surface 31A reflecting the laser beam L2A of the mirror 31 is R3 (R3 = R1 / sin θ). It is set to be.

  The motor 32 includes a rotation shaft (not shown) that can be rotated by an energization operation, and the support shaft body 6 is coaxially assembled to the rotation shaft. As shown in FIG. 2, a pair of sandwiching portions 33 </ b> A and 33 </ b> A are provided at the front end portion of the support shaft body 6 so as to face each other by being cut out along a plane passing through the axis of the support shaft body 6. Yes. Both clamping parts 33A and 33A fix the mirror 31 by clamping the lower end edge of the mirror 31 from the plate thickness direction through a resin adhesive. Both sandwiching portions 33A and 33A are disposed at positions adjacent to the outer edge portion of the reflecting surface 31A in order to reduce the weight of the mirror 31, and the height dimension R4 of the mirror 31 is made as small as possible.

  The converging lens 40 is for converging the laser beam L2A reflected by the mirror 31 to irradiate the workpiece W. The height of the workpiece W is set so as to be the focal position of the laser beam L2A emitted from the converging lens 40. Accordingly, the laser beam L2A emitted from the converging lens 40 can be scanned on the workpiece W by driving the mirror 31 with the motor 32, and laser processing can be performed.

  Between the beam expander 20 and the mirror 31, a shielding member 35 made of metal and having a circular hole 35A having the same diameter as the laser beam L2A is disposed. The circular hole 35A is provided so as to penetrate the shielding member 35 in the thickness direction, and is disposed coaxially with the laser beam L2A. Therefore, the tail light L2B is prevented from irradiating the holding portion 33A of the support shaft body 33. It has become so. Further, the shielding member 35 is arranged closest to a position in the vicinity of the support shaft 33 that does not interfere with the mirror 31 when the mirror 31 is driven by the motor 32. For this reason, the skirt light L2B is diffracted by the shielding member 35, thereby changing the direction toward the support shaft 33, and the amount of irradiation of the clamping portion 33A can be reduced. Furthermore, the shielding member 35 is fixed on a pedestal 34 of the galvanomirror device 30 as shown in FIG. Thereby, the positional relationship between the mirror 31 and the shielding member 35 can be kept constant.

  In the present embodiment, a light-absorbing paint (matte black or the like) is applied to the irradiation surface 35B of the shielding member 35 to which the tail light L2B is irradiated. For this reason, the base light L2B can be absorbed by the irradiation surface 35B, and the base light L2B is prevented from being reflected by the irradiation surface 35B. As a means for shielding the skirt light L2B, a reflection mirror may be installed in place of the shielding member 35, and the skirt light L2B reflected by the reflection mirror may be absorbed in other places. In short, any other method may be used as long as it can block the base light L2B and prevent the support shaft 33 from being irradiated.

The present embodiment has the above-described structure, and the operation thereof will be described subsequently.
When the laser light L1 is emitted from the laser light source 10 toward the incident side lens 21 of the beam expander 20, the laser light L1 is enlarged by the incident side lens 21 and is converted into parallel light by the emission side lens 22, and has a predetermined diameter. Laser light L2 is generated. Of the laser light L2, the laser beam L2A passes through the circular hole 35A of the shielding member 35, is reflected by the mirror 31 of the galvanomirror device 30, and is emitted toward the converging lens 40. The laser beam L2A is converged by the converging lens 40 and irradiated onto the workpiece W at the focal position. On the other hand, the base light L2B is absorbed by the light-absorbing paint on the irradiation surface 35B of the shielding member 35. Thereby, it is prevented that the clamping part 33A of the support shaft body 35 is irradiated by the base light L2B.

As described above, in the present embodiment, the following effects can be obtained.
1. The base light L2B is blocked by the irradiation surface 35B of the shielding member 35, and the support shaft body 33 is prevented from being irradiated. As a result, the connecting portion between the mirror 31 and the holding portion 33A of the support shaft 33 is not affected by thermal expansion or the like, and the scanning characteristics of the mirror 31 can be satisfactorily maintained.

2. The diameter R2 of the mirror 31 can be made substantially equal or slightly larger beam diameter defined by 1 / e ^2. Accordingly, the mirror 31 can be reduced in weight, and the inertia of the mirror 31 can be reduced and the operation speed can be increased.

  3. When the laser beam is shielded by the shielding member 35, it is inevitable that slight light diffraction occurs at the inner peripheral edge of the circular hole 35 </ b> A of the shielding member 35 when viewed microscopically. When such diffraction occurs, the laser light penetrating through the circular hole 35A of the shielding member 35 spreads away from the shielding member 35, and is eventually irradiated to the holding portion 33A of the support shaft 33. On the other hand, in the present embodiment, the shielding member 35 is arranged closest to a position in the vicinity of the support shaft 33 that does not interfere with the mirror 31 when the mirror 31 is driven by the motor 32. The amount of the support shaft 33 irradiated by the tail light L2B can be reduced to the minimum, and the tail light L2B can be efficiently shielded.

  4). In the present embodiment, for example, there is no accumulation of attachment errors compared to a configuration in which the motor and the shielding member are separately attached to a common chassis, so that the positional relationship between the shielding member 35 and the motor 32 can be kept constant. This means that the positional relationship between the shielding member 35 and the mirror 31 can be kept constant with high accuracy, so that it is possible to reliably prevent the support shaft 33 from being irradiated with laser light. Further, since the shielding member 35 and the motor 32 are unitized, the handling is facilitated while maintaining the positional relationship between them with high accuracy.

  5. Since the bottom light L2B can prevent the outer peripheral portion of the reflecting surface 31A of the mirror 31 from being heated, an increase in the temperature of the outer peripheral portion of the reflecting surface 31A and thus the connecting portion between the mirror 31 and the support shaft 33 can be suppressed.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.

(1) In the present embodiment, the holding part 33A of the support shaft 33 and the mirror 31 are fixed using an adhesive, but according to the present invention, a machine using screws, bolts or the like is used. It is also possible to connect them.
(2) In the present embodiment, the diameter R1 of the laser beam L2A is set to be a beam diameter defined by 1 / e ^2. However, according to the present invention, the mirror 31 is provided on the exit side lens 22. maximum diameter need only be reflected configured to be able to small laser beam L2 than the diameter dimension R1 is not limited to the beam diameter defined by 1 / e ^2.

  (3) In the present embodiment, the shielding member 35 is arranged closest to a position in the vicinity of the support shaft 33 that does not interfere with the mirror 31 when the mirror 31 is driven by the motor 32, but according to the present invention. And the shielding member 35 should just be a position which can prevent the tail light L2B from irradiating the support shaft body 33 between the beam expander 20 and the mirror 31. In the case of adopting such a configuration, it is desirable to separately provide means for shielding the diffracted light of the base light L2B.

(4) In the present embodiment, the shielding member 35 is illustrated as being fixed on the pedestal 34 of the galvanomirror device 30, but according to the present invention, the shielding member 35 is fixed to another member. It may be.
(5) In the present embodiment, the irradiation surface 35B of the shielding member 35 is illustrated in which the radially outer portion of the laser beam L2A is continuously provided along the entire circumference. Accordingly, the irradiation surface 35B of the shielding member does not necessarily have to be continuous along the entire circumference, and only the connection portion between the support shaft 33 and the mirror 31 is hidden from the laser beam emitting side of the beam expander 20. Thus, the connection portion may be prevented from being irradiated with laser light.

The partially cutaway top view which shows the laser processing apparatus in Embodiment 1. The perspective view which shows the state by which the support shaft body is prevented from being irradiated by the tail light by the shielding member

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laser processing apparatus 10 ... Laser light source 20 ... Beam expander 22 ... Output side lens 31 ... Mirror 32 ... Motor 33 ... Supporting shaft body 35 ... Shielding member 35A ... Circular hole 40 ... Converging lens L1 ... Laser beam L2 ... Laser beam L2A: Laser beam L2B: Base light (laser light located outside the laser beam)
R1 ... Diameter of laser beam

Claims (5)

A laser light source for emitting laser light;
A beam expander having a plurality of lenses and expanding and emitting laser light from the laser light source;
A mirror for reflecting the laser beam emitted from the beam expander;
A motor for driving the mirror;
A support shaft for assembling the mirror to the rotating shaft of the motor;
A converging lens that converges the laser beam reflected by the mirror and irradiates the object to be processed;
A laser processing apparatus for processing the workpiece by scanning the laser beam emitted from the convergent lens by driving the mirror with the motor,
The mirror is configured to be able to reflect a laser beam having a beam diameter emitted from the exit side lens of the beam expander,
A shielding member is disposed between the beam expander and the mirror to prevent the laser beam positioned outside the laser beam emitted from the beam expander from irradiating the support shaft body. A laser processing apparatus characterized by the above. The diameter of the laser beam is a beam intensity that is 1 / e ² (13.5%) or more of the peak value of a Gaussian profile measured on a plane orthogonal to the optical axis of the laser light emitted from the beam expander. The laser processing apparatus according to claim 1, wherein the beam diameter is defined by the width of the beam. 3. The shielding member according to claim 1, wherein the shielding member is arranged closest to a position in the vicinity of the support shaft that does not interfere with the mirror when the mirror is driven by the motor. Laser processing equipment. The laser processing apparatus according to claim 1, wherein the shielding member is provided integrally with the motor. The said shielding member has a circular hole with the same diameter as the laser beam radiate | emitted from the said beam expander, and the said circular hole is arrange | positioned coaxially with the said laser beam. The laser processing apparatus according to claim 4.

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