JP2010274292A - Laser processing equipment - Google Patents

Abstract

The present invention realizes a processing that does not cause anisotropy with a linearly polarized laser beam with a simple configuration.
A processing head provided with a polarization plane holding fiber that irradiates a linearly polarized laser beam having a polarization plane held in a straight line, and a target to be irradiated with the linearly polarized laser beam emitted from the polarization plane holding fiber. A processing table 4 on which a workpiece is placed, a moving means 8 for relatively moving the processing head 3 and the processing table 4 in a two-dimensional direction intersecting the optical axis R of the linearly polarized laser beam, and light of the linearly polarized laser beam A rotating unit that rotates the polarization-maintaining fiber 2 about the axis R, and the rotating unit is driven according to the driving of the moving unit 8, and is linear with respect to the relative moving direction of the processing head 3 and the processing table 4. And control means 5 for maintaining the polarization direction of the polarized laser light constant.
[Selection] Figure 1

Description

  The present invention relates to a laser processing apparatus for processing a workpiece by irradiating the workpiece with linearly polarized laser light.

  The laser processing apparatus processes the workpiece by irradiating the workpiece with laser light. This laser processing apparatus includes a processing head for irradiating a laser beam and a processing table on which the workpiece is placed, and the processing head and the processing table are relatively two-dimensionally moved so that the workpiece can have various shapes. Can be cut into pieces.

  Here, the laser light emitted from the processing head includes linearly polarized laser light and circularly polarized laser light. The linearly polarized laser light is irradiated on a workpiece in a linear shape with a constant vibration direction in polarized light in which an electric field and a magnetic field vibrate in a specific direction. On the other hand, circularly polarized laser light is irradiated to a workpiece in a circular shape by drawing a circle as the vibration propagates in polarized light. The linearly polarized laser beam has a special processing performance when the vibration direction and the two-dimensional movement direction coincide with each other, but when the vibration direction and the two-dimensional movement direction deviate from each other, the linear polarization laser beam has a special processing performance. Anisotropy of processing such as inferior processing performance occurs. On the other hand, the circularly polarized laser beam has a constant vibration width with respect to the two-dimensional movement direction, and thus does not cause anisotropy in processing, but linearly polarized light when the vibration direction and the two-dimensional movement direction match. Processing performance is inferior compared to laser light.

  Conventionally, a laser processing apparatus that does not cause anisotropy in processing with linearly polarized laser light is known (see, for example, Patent Documents 1 and 2).

  The laser processing apparatus described in Patent Literature 1 includes a laser resonator including a total reflection mirror and an output mirror, and an optical element including a reflection mirror that is disposed on the optical axis of the laser resonator and selects a polarization component. Linearly polarized laser light is generated, and the optical element and the total reflection mirror are integrally provided so as to be rotatable with respect to the laser optical axis, and the movement direction of the workpiece and the polarization direction of the linearly polarized laser light are controlled to coincide. Is.

  The laser processing apparatus described in Patent Document 2 includes a polarizing element that divides a randomly polarized laser beam emitted from a laser oscillator into two linearly polarized laser beams, and a traveling direction of the two divided linearly polarized laser beams in the same direction. And a plurality of total reflection mirrors whose polarization planes are parallel to each other, and a driving unit that integrally rotates the polarization element and the total reflection mirror about the rotationally symmetric rotation axis of two linearly polarized laser beams whose polarization planes are parallel. Has been. Then, the linear polarization direction of the two linearly polarized laser beams condensed by the condenser lens is controlled to coincide with the processing direction of laser processing.

JP-A-4-339586 JP-A-7-266071

  However, in the laser processing apparatuses described in Patent Documents 1 and 2, since the optical element and the total reflection mirror are integrally rotated, the positional relationship between the optical element and the total reflection mirror is maintained, and the rotation center is maintained. Since the structure is complicated and the number of parts increases, there is a problem that the adjustment of the optical axis takes time and the manufacturing cost increases.

  The present invention has been made in view of the above, and an object of the present invention is to provide a laser processing apparatus capable of realizing processing that does not cause anisotropy with linearly polarized laser light with a simple configuration.

  In order to solve the above-described problems and achieve the object, the present invention provides a linearly polarized laser having a plane of polarization held linearly in a laser processing apparatus that processes a workpiece by irradiating the workpiece with laser light. A processing head provided with a polarization-maintaining fiber for irradiating light, a processing table for placing the workpiece irradiated with the linearly-polarized laser light emitted from the polarization-maintaining fiber, and a linearly-polarized laser light A moving means for relatively moving the processing head and the processing table in a two-dimensional direction intersecting the optical axis; a rotating means for rotating the polarization plane holding fiber about the optical axis of the linearly polarized laser beam; and the moving Control means for driving the rotating means in accordance with the drive of the means, and maintaining the polarization direction of the linearly polarized laser beam constant with respect to the relative movement direction of the machining head and the machining table; Characterized by comprising a.

  According to the present invention, the processing direction and the polarization direction of the linearly polarized laser beam are always maintained in a constant direction, and processing can be performed in an optimal state at all times. At this time, since the polarization-maintaining fiber is rotated, the optical element and the total reflection mirror for making linearly polarized laser light are rotated together as in the conventional case, resulting in a complicated structure and a large number of parts. Never become. As a result, processing that does not cause anisotropy with linearly polarized laser light can be realized with a simple configuration.

FIG. 1 is a schematic diagram of a laser processing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a schematic sectional view of a polarization-maintaining fiber applied to the laser processing apparatus shown in FIG. FIG. 3 is a schematic view of a machining head applied to the laser machining apparatus shown in FIG. FIG. 4 is a schematic diagram of a machining head of the laser machining apparatus according to the second embodiment of the present invention. FIG. 5 is a schematic view of a machining head of the laser machining apparatus according to the third embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of the fiber holding cylinder of the laser processing apparatus according to the fourth embodiment of the present invention. FIG. 7 is a schematic cross-sectional view of the fiber holding cylinder of the laser processing apparatus according to the fifth embodiment of the present invention. FIG. 8 is a schematic diagram showing the polarization direction detecting means of the laser processing apparatus according to the sixth embodiment of the present invention.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
As shown in FIG. 1, the laser processing apparatus includes a laser oscillator 1, a polarization-maintaining fiber 2, a processing head 3, a processing table 4, and a control unit 5.

  The laser oscillator 1 generates laser light. In the present embodiment, the laser oscillator 1 generates linearly polarized laser light whose electric fields are all aligned in the same direction. The driving of the laser oscillator 1 is controlled by the control means 5.

  The polarization plane maintaining fiber 2 transmits the linearly polarized laser beam generated from the laser oscillator 1 while maintaining the direction of the electric field. For example, as shown in FIG. 2, the polarization-maintaining fiber 2 of the present embodiment includes a core 21, a clad 22 formed concentrically around the core 21, and two clads 22 provided in the clad 22. It is comprised with the stress provision part 23. FIG. The stress applying portion 23 has a circular cross section and is arranged symmetrically around the core 21 in the cladding 22. In the polarization-maintaining fiber 2, the direction of passing through the core 21 on the symmetry center line of the two stress applying portions 23 is the polarization direction. Note that the polarization-maintaining fiber 2 is not limited to the above structure as long as it transmits the linearly polarized laser light while maintaining the direction of the electric field.

  The processing head 3 irradiates the workpiece W with linearly polarized laser light transmitted from the laser oscillator 1 through the polarization plane holding fiber 2. The processing head 3 includes a fiber holding unit 31, a collimator lens 32, and a condenser lens 33. have. The fiber holding unit 31 holds the distal end side of the polarization plane holding fiber 2 that emits linearly polarized laser light inside the base plate 31a, the top plate 31b, and the side plate 31c shown in FIG. . The linearly polarized laser beam emitted from the polarization plane holding fiber 2 is output to the outside of the processing head 3 from the laser emission window 31 d provided on the bottom plate 31 a of the fiber holding unit 31. The collimator lens 32 converts the linearly polarized laser beam emitted from the polarization plane holding fiber 2 and diffused into parallel light. The condensing lens 33 condenses the linearly polarized laser light converted into parallel light by the collimator lens 32 and irradiates it toward the workpiece W.

  The processing head 3 includes a rotating means 6. The rotating means 6 rotates the polarization plane holding fiber 2 around the optical axis R of the linearly polarized laser beam. As shown in FIG. 3, the rotating means 6 is disposed in the fiber holding portion 31 of the processing head 3 and supports the rotation. The unit 61, the rotation drive unit 62, and the rotation transmission unit 63 are configured.

  The polarization plane holding fiber 2 is fixed to the fiber holding cylinder 7. The fiber holding cylinder 7 is inserted through the polarization-maintaining fiber 2 through a cylindrical center and fixed in a form in which the optical axis R of the polarization-maintaining fiber 2 is aligned with the cylindrical center.

  The rotation support portion 61 supports the fiber holding cylinder 7 and includes a ball caster 61a, a lower ball bearing 61b, and an upper ball bearing 61c. The ball caster 61 a is fixed to the upper surface of the bottom plate 31 a of the fiber holding unit 31 and supports the bottom of the fiber holding cylinder 7 from below while being in contact with the bottom of the fiber holding cylinder 7. The lower ball bearing 61b is fixed to the upper surface of the bottom plate 31a of the fiber holding portion 31, and supports the fiber holding cylinder 7 so as to be rotatable about the cylindrical center while contacting the lower outer peripheral surface of the fiber holding cylinder 7. The upper ball bearing 61 c is fixed to the lower surface of the top plate 31 b of the fiber holding unit 31, and supports the fiber holding cylinder 7 so as to be rotatable about the cylindrical center while being in contact with the upper outer peripheral surface of the fiber holding cylinder 7. That is, the rotation support unit 61 supports the fiber holding cylinder 7 that fixes the optical axis R of the polarization plane holding fiber 2 so as to rotate at the center of the cylinder, and the fiber holding cylinder 7 rotates. Further, the vertical and horizontal positions of the optical axis R of the polarization-maintaining fiber 2 are configured not to move.

  The rotation driving unit 62 is configured as a servo motor fixed to the upper surface of the bottom plate 31 a of the fiber holding unit 31. The rotating shaft 62 a extending from the rotation driving unit 62 is rotatably supported by a bearing 62 b whose tip is fixed to the lower surface of the top plate 31 b of the fiber holding unit 31. For this reason, the rotation drive unit 62 is arranged such that the axis of the rotation shaft 62 a is parallel to the optical axis R of the polarization-maintaining fiber 2 that is rotatably supported by the rotation support unit 61. The driving of the rotation driving unit 62 is controlled by the control means 5.

  The rotation transmission unit 63 includes a drive gear 63 a provided on the rotation shaft 62 a of the rotation drive unit 62 and a driven gear 63 b provided on the fiber holding cylinder 7. The drive gear 63a and the driven gear 63b are provided so as to mesh with each other. Thereby, the rotation of the rotating shaft 62 a due to the driving of the rotation driving unit 62 is transmitted to the fiber holding cylinder 7. As a result, the polarization-maintaining fiber 2 is rotated around its optical axis R.

  The processing table 4 places the workpiece W on the position of the condensing point of the linearly polarized laser beam condensed by the condenser lens 33 of the processing head 3, and the placed workpiece W is linearly polarized laser. It is moved in a two-dimensional direction orthogonal (crossing) to the optical axis R of the light. The processing table 4 includes moving means 8 that moves the workpiece W in a two-dimensional direction.

  As shown in FIG. 1, the moving means 8 includes a servo motor 81 that moves the machining table 4 in the X direction and a servo motor 82 that moves the machining table 4 in the Y direction. The driving of the servo motors 81 and 82 in the moving means 8 is controlled by the control means 5. That is, when the servo motors 81 and 82 are driven, the machining table 4 moves in the two-dimensional direction of the X direction and the Y direction, and the workpiece W moves in the two-dimensional direction together with the machining table 4. In this way, by placing the workpiece W at the position of the condensing point of the linearly polarized laser beam and moving the workpiece W in a two-dimensional direction orthogonal to the optical axis R of the linearly polarized laser beam, The workpiece W can be processed (cut). Note that the linearly polarized laser light is kept linearly polarized at the condensing point irradiated to the workpiece W.

  Although not explicitly shown in the figure, the moving means 8 may be configured to move the processing head 3 in a two-dimensional direction orthogonal to (intersect) the optical axis R of the linearly polarized laser light irradiated on the workpiece W. Good. That is, the moving means 8 moves the processing head 3 and the processing table 4 relative to each other in a two-dimensional direction orthogonal to (intersects) the optical axis R of the linearly polarized laser light irradiated on the workpiece W. That's fine.

  The control means 5 is constituted by a microcomputer or the like, and operates the laser oscillator 1, the rotating means 6 of the machining head 3, and the moving means 8 of the machining table 4. That is, the control means 5 is connected to the laser oscillator 1, the rotation drive unit 62 of the rotation means 6 in the machining head 3, and the movement means 8 of the machining table 4.

  The control means 5 is preferably configured as an NC control means for controlling the entire laser processing apparatus. The control means 5 stores processing information for processing the workpiece W in advance in a storage unit 51 such as a RAM or a ROM, and controls driving of the laser oscillator 1 and the moving means 8 based on the processing information. . In particular, the control means 5 has the direction information of the polarization direction optimum for the processing of the linearly polarized laser light irradiated to the workpiece W with respect to the processing direction to the workpiece W when the processing table 4 is moved. Stored in the storage unit 51 in advance. That is, the control means 5 performs polarization of the linearly polarized laser beam so that the polarization direction of the linearly polarized laser beam is optimal for processing relative to the relative movement direction (processing direction) of the processing head 3 and the processing table 4. The direction is determined, and the drive of the rotation drive unit 62 is controlled to rotate the polarization-maintaining fiber 2. The control means 5 makes the polarization direction constant with respect to the processing direction of the workpiece W, which is the relative movement direction of the processing head 3 and the processing table 4, so that the polarization direction is optimal for processing. maintain.

  Here, as the polarization direction that is optimal for processing, for example, the polarization direction is made to coincide with the relative movement direction (processing direction) of the processing head 3 and the processing table 4. Matching the polarization direction of the linearly polarized laser beam with the relative movement direction (processing direction) of the machining head 3 and the machining table 4 means that the condensing point of the linearly polarized laser beam with respect to the workpiece W is When moving linearly, it means that the direction of polarization of the linearly polarized laser beam coincides with the straight line. Further, when the condensing point of the linearly polarized laser beam moves in a curved manner with respect to the workpiece W, it means that the polarization direction of the linearly polarized laser beam coincides with the tangent of the curve in the moving process. In addition, as the polarization direction optimal for processing, for example, the polarization direction may be rotated by a predetermined angle (preferably 90 °) with respect to the relative movement direction (processing direction) between the processing head 3 and the processing table 4. When the polarization direction of the linearly polarized laser beam is rotated by a predetermined angle (90 °) with respect to the relative movement direction (processing direction) between the processing head 3 and the processing table 4, the linearly polarized laser is used with respect to the workpiece W. When the light condensing point moves linearly, it means that the polarization direction of the linearly polarized laser light is rotated by a predetermined angle (90 °) along the straight line. Further, when the condensing point of the linearly polarized laser beam moves in a curved line with respect to the workpiece W, the polarization direction of the linearly polarized laser beam is rotated by a predetermined angle (90 °) to the tangent to the curve in the moving process. Means.

  In the laser processing apparatus having such a configuration, the linearly polarized laser light generated by the laser oscillator 1 is transmitted through the polarization plane holding fiber 2 and emitted from the processing head 3, and is applied to the workpiece W placed on the processing table 4. Irradiate. Next, the processing head 3 and the processing table 4 are moved relative to each other in a two-dimensional direction orthogonal to the optical axis R of the linearly polarized laser beam, and the position of the condensing point of the linearly polarized laser beam is moved relative to the workpiece W. By doing so, the workpiece W is processed (cut). Then, when processing the workpiece W, the rotating means 6 is driven according to the driving of the moving means 8, and the polarization direction of the linearly polarized laser beam is always kept constant with respect to the processing direction.

  In laser processing, the processing capability differs greatly depending on the relationship between the processing direction and the polarization direction of the linearly polarized laser beam. This is because the absorption of the linearly polarized laser light into the material of the workpiece W differs depending on the polarization direction. For this reason, in a state where the polarization direction of the linearly polarized laser beam is fixed, anisotropy occurs in the processing performance with the two-dimensional relative movement between the processing head 3 and the processing table 4.

  On the other hand, in the laser processing apparatus of the present embodiment, linearly polarized laser light is transmitted through the polarization plane holding fiber, and this polarization plane holding fiber is subjected to two-dimensional relative movement between the processing head 3 and the processing table 4. The movement direction (processing direction) and the polarization direction are kept constant. As a result, the processing direction and the polarization direction of the linearly polarized laser beam are always maintained in a constant direction, so that processing can always be performed in an optimum state, and processing capability can be stabilized.

  Conventionally, since the optical element and the total reflection mirror for making linearly polarized laser light are rotated together, the positional relationship between the optical element and the total reflection mirror is maintained, and the rotation center is maintained and the rotation is maintained. Since the structure must be made and the structure is complicated and the number of parts is increased, there are problems in that it takes time to adjust the optical axis and the manufacturing cost increases.

  In this regard, according to the laser processing apparatus of the present embodiment, since the polarization-maintaining fiber 2 is rotated, processing that does not cause anisotropy with linearly polarized laser light can be realized with a simple configuration. Is possible.

  The above-described laser processing apparatus has been described with the configuration in which the processing head 3 and the processing table 4 are relatively moved two-dimensionally. However, in the configuration in which the processing head 3 and the processing table 4 are relatively moved in three dimensions, The polarization direction of the linearly polarized laser beam may be maintained constant with respect to the two-dimensional movement direction orthogonal (crossing) to the optical axis R of the linearly polarized laser beam.

Embodiment 2. FIG.
The laser processing apparatus of the second embodiment is different from the laser processing apparatus of the first embodiment described above only in the configuration of the rotation transmission unit, and the other configurations are the same. Therefore, in the second embodiment described below, only the rotation transmission unit will be described, and the same components as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

  As shown in FIG. 4, the rotation transmission unit 64 is configured by winding an endless belt 64 a around the rotation shaft 62 a of the rotation driving unit 62 and the fiber holding cylinder 7. Thereby, the rotation of the rotating shaft 62 a due to the driving of the rotation driving unit 62 is transmitted to the fiber holding cylinder 7. As a result, the polarization-maintaining fiber 2 is rotated around its optical axis R.

  The pulley 64b is provided on the rotating shaft 62a, the pulley 64c is provided on the fiber holding cylinder 7, and the belt 64a is wound through the pulleys 64b and 64c, so that the belt 64a is reliably wound and the rotation is reliably transmitted. Can be done. Although not shown in the drawing, if comb-like teeth arranged in the rotational direction are provided on the inner side of the belt 64a and teeth that mesh with the teeth of the belt 64a are provided on the outer circumferences of the pulleys 64b and 64c, the belt It is possible to more reliably wind 64a and to transmit rotation more reliably.

Embodiment 3 FIG.
The laser processing apparatus of the third embodiment is different from the laser processing apparatuses of the first and second embodiments described above only in the configuration of the rotating means, and the other configuration is the same. Therefore, in the third embodiment described below, only the rotation transmission unit will be described, the same components as those in the first and second embodiments will be denoted by the same reference numerals, and the description thereof will be omitted.

  As shown in FIG. 5, the rotating means 9 rotates the polarization plane holding fiber 2 around the optical axis R of the linearly polarized laser beam. The rotating means 9 is disposed in the fiber holding section 31 of the processing head 3 and is a hollow servo. The motor includes a hollow portion 91 and a hollow portion drive portion 92.

  The hollow portion 91 supports the fiber holding cylinder 7 and is formed in a cylindrical shape so as to pass through the fiber holding cylinder 7. A cylindrical support plate 91 a is fixed to the lower portion of the hollow portion 91 so as to open the central portion of the hollow portion 91. The bottom of the fiber holding cylinder 7 is in contact with the upper surface of the support plate 91a, and is fixed to the support plate 91a with a fixing screw 91b. In the fiber holding cylinder 7 fixed by the fixing screw 91b, the optical axis of the polarization plane holding fiber 2, which is the center of the cylindrical shape, coincides with the cylindrical center in the hollow portion 91.

  The hollow part driving part 92 is formed in a cylindrical shape provided on the outer periphery of the hollow part 91. The hollow part drive unit 92 integrally includes a bearing mechanism that rotatably supports the hollow part 91 at the cylindrical center of the hollow part 91 and a drive mechanism that rotationally drives the hollow part 91. The driving of the hollow drive unit 92 is controlled by the control means 5.

  In the rotating means 9, the hollow portion 91 rotates directly with the fiber holding cylinder 7 by the driving of the hollow portion driving portion 92. As a result, the polarization-maintaining fiber 2 is rotated around its optical axis R.

  Thus, by adopting the rotating means 9 as a hollow servo motor, the polarization plane holding fiber 2 is rotated with the center of rotation on the optical axis R. For this reason, in the configuration in which the rotation shaft is separately provided and the rotation is transmitted, a transmission loss may occur during the transmission of the rotation, but the generation of the transmission loss can be suppressed. In addition, since the bearing mechanism and the drive mechanism are integrally formed, it is possible to reduce the size of the processing head 3 in which the rotating means 9 is disposed.

Embodiment 4 FIG.
The laser processing apparatus of the fourth embodiment is characterized by the configuration of the fiber holding cylinder in the laser processing apparatus of the first to third embodiments described above, and the other configurations are the same. Therefore, in Embodiment 4 described below, only the fiber holding cylinder will be described.

  As shown in FIG. 6, the fiber holding cylinder 7 has an inner cylinder 71 and an outer cylinder 72 formed in a cylindrical shape. The inner cylinder 71 fixes the polarization-maintaining fiber 2 in a form in which the optical axis R of the polarization-maintaining fiber 2 coincides with the center of the cylindrical shape while the polarization-maintaining fiber 2 is inserted. The outer cylinder 72 has an inner diameter larger than the outer diameter of the inner cylinder 71, and the inner cylinder 71 is inserted and accommodated therein, and is fixed to the rotating means 6 and 9. The fiber holding cylinder 7 has a positioning portion 73. The positioning portion 73 includes an upper screw hole 73a and a lower screw hole 73b penetrating toward the center at a plurality of locations (for example, four locations) of the upper and lower portions of the outer cylinder 72, and the screw holes 73a, The upper shaft adjusting screw 73c and the lower shaft adjusting screw 73d are screwed into 73b.

  The inner cylinder 71 is inserted into the outer cylinder 72 so as to be sandwiched from outside by an upper shaft adjusting screw 73c screwed into the upper screw hole 73a of the outer cylinder 72 and a lower shaft adjusting screw 73d screwed into the lower screw hole 73b. Fixed to.

  Here, although the polarization-maintaining fiber 2 is fixed at the center of the inner cylinder 71, when the inner cylinder 71 is inserted into the outer cylinder 72 and assembled, the position of the fiber end surface that appears at the lower portion of the inner cylinder 71 and In some cases, the position of the optical axis R does not coincide with the rotation center of the rotation means 6, 9. In this case, even if the polarization plane holding fiber 2 is rotated, the output position and the output direction of the linearly polarized laser beam emitted from the end face of the fiber and irradiated onto the workpiece W change, and the accuracy of laser processing is reduced. . Therefore, in the laser processing apparatus of the fourth embodiment, the position of the inner cylinder 71 fixed to the outer cylinder 72 is adjusted by tightening or loosening the upper shaft adjustment screw 73c or the lower shaft adjustment screw 73d, thereby adjusting the inner side. It is possible to make the position of the fiber end face of the polarization plane holding fiber 2 fixed to the cylinder 71 and the position of the optical axis R coincide with the center of rotation by the rotating means 6 and 9.

  As described above, the fiber holding cylinder 7 is constituted by the inner cylinder 71, the outer cylinder 72, and the positioning portion 73, and the optical axis R of the polarization plane holding fiber 2 is made to coincide with the rotation center by the rotating means 6 and 9. Optical axis defining means is provided.

  The polarization-maintaining fiber 2 may be burned out due to return light from the workpiece W or dirt on the fiber end face, and is a component that needs to be replaced. Therefore, by providing the optical axis defining means, it is possible to maintain the accuracy of laser processing as before the replacement even after the polarization plane holding fiber 2 is replaced.

Embodiment 5 FIG.
The laser processing apparatus of the fifth embodiment has further features in the configuration of the positioning portion of the fiber holding cylinder in the above-described fourth embodiment, and the other features are the same as those of the laser processing apparatus in the first to fourth embodiments described above. It is the same configuration. Therefore, in the fifth embodiment described below, only the positioning portion of the fiber holding cylinder will be described, and the same reference numerals are given to the same components as those in the first to fourth embodiments, and the description thereof will be omitted.

  As shown in FIG. 7, the positioning portion 73 includes an inner wedge-shaped portion 73e having a conical shape with a lower outer peripheral surface of the inner cylinder 71 facing downward, and a lower inner peripheral surface of the outer cylinder 72 facing downward. And an outer wedge-shaped portion 73f constricted in a circular mortar shape. The inner wedge-shaped part 73e is formed at the center of the inner cylinder 71, with the optical axis R of the polarization plane holding fiber 2 fixed to the inner cylinder 71 as a rotationally symmetric center. The outer wedge-shaped portion 73f is the center of the outer cylinder 72 and is formed with the rotation center of the rotation means 6 and 9 as the center of rotational symmetry.

  Then, by inserting the inner cylinder 71 from above the outer cylinder 72, the sharp outer peripheral surface of the inner wedge-shaped portion 73e and the lower inner peripheral surface of the outer wedge-shaped portion 73f are in contact with each other. The centers of mutual rotational symmetry coincide. Thereby, in the lower part of the fiber holding cylinder 7, the position of the fiber end face of the polarization plane holding fiber 2 fixed to the inner cylinder 71 and the position of the optical axis R coincide with the rotation center by the rotating means 6 and 9.

  Further, the angle of the sharp bottom portion of the inner wedge-shaped portion 73e is formed smaller than the angle of the narrowed lower portion of the outer wedge-shaped portion 73f. Furthermore, the outer diameter of the upper part where the inner wedge-shaped part 73e spreads is smaller than the inner diameter of the upper part where the outer wedge-shaped part 73f spreads. As a result, the pointed outer peripheral surface of the inner wedge-shaped portion 73e and the inner peripheral surface of the lower portion of the outer wedge-shaped portion 73f are located at the position of the fiber end surface of the polarization-maintaining fiber 2 and the position of the optical axis R. And the center of rotation by the rotating means 6 and 9 become a fulcrum, and the inner cylinder 71 can be tilted with respect to the outer cylinder 72.

  The upper shaft adjusting screw 73c is tightened or loosened to adjust the position of the upper portion of the inner cylinder 71 fixed to the outer cylinder 72, so that the lower portion of the fiber holding cylinder 7 and the upper portion of the fiber holding cylinder 7 are adjusted. The position of the fiber end face of the polarization plane holding fiber 2 fixed to the inner cylinder 71 and the position of the optical axis R coincide with the center of rotation by the rotating means 6 and 9.

  As described above, the fiber holding cylinder 7 includes the inner cylinder 71, the outer cylinder 72, and the positioning portion 73 (the inner wedge portion 73e, the outer wedge portion 73f, the upper screw hole 73a, and the upper shaft adjusting screw 73c). An optical axis defining means configured to align the optical axis R of the polarization-maintaining fiber 2 with the rotation center of the rotating means 6 and 9 is provided.

Embodiment 6 FIG.
The laser processing apparatus of the sixth embodiment is further provided with a polarization direction detecting unit with respect to any one of the above-described laser processing apparatuses of the first to fifth embodiments. It is the same structure as the laser processing apparatus of the form 5. Therefore, in the sixth embodiment described below, only the polarization direction detecting means will be described, and the same components as those in the first to fifth embodiments will be denoted by the same reference numerals and the description thereof will be omitted.

  As shown in FIG. 8, the polarization direction detection means 10 includes a beam splitter 10a, a Brewster window 10b, and a power meter 10c.

  The beam splitter 10 a is disposed on the optical path of the parallel light of the linearly polarized laser light between the collimator lens 32 and the condenser lens 33. The beam splitter 10a reflects a part of linearly polarized laser light that does not affect the processing. Note that the arrangement of the beam splitter 10a between the collimator lens 32 and the condenser lens 33 is to reduce the power density in the beam splitter 10a, but a linearly polarized laser can be used as long as it does not affect the processing. The beam splitter 10a may be disposed at any position on the optical path of light.

  The Brewster window 10b transmits a part of the linearly polarized laser beam reflected by the beam splitter 10a and reflects the remaining linearly polarized laser beam. The transmittance and the reflectance in the Brewster window 10b change depending on the polarization direction of the linearly polarized laser light incident on the Brewster window 10b and the relative direction of the Brewster window 10b. Therefore, if the polarization direction of the linearly polarized laser beam incident on the Brewster window 10b changes, the output of the linearly polarized laser beam that passes through the Brewster window 10b also changes.

  The power meter 10c monitors the output of linearly polarized laser light transmitted through the Brewster window 10b. Thereby, it is possible to determine the polarization direction of the linearly polarized laser beam reflected by the beam splitter 10a and transmitted through the Brewster window 10b. As a result, it is possible to detect the polarization direction of the linearly polarized laser beam that is transmitted through the beam splitter 10a and applied to the workpiece W.

  The power meter 10 c is connected to the control means 5. The control means 5 determines the polarization direction based on the output from the power meter 10c, and adjusts the direction of the fiber holding cylinder 7 (polarization plane holding fiber 2) so that the polarization direction is optimal for the processing conditions.

  The linearly polarized laser beam reflected by the Brewster window 10b is absorbed by the damper 10d.

  Thus, by constantly monitoring the polarization direction of the linearly polarized laser beam, the polarization direction of the linearly polarized laser beam emitted from the polarization-maintaining fiber 2 can always be accurately grasped, so that high processing accuracy can be maintained. It becomes possible. In addition, by constantly monitoring the polarization direction of the linearly polarized laser beam, it is not necessary to memorize the orientation of the polarization plane holding fiber 2 when assembling the laser processing apparatus or adjusting the optical axis R. Further, it is not necessary to adjust the direction of the polarization-maintaining fiber 2 at the time of adjustment, and readjustment is not required even if the orientation of the polarization-maintaining fiber 2 is shifted due to assembly tolerances.

  Note that the output of the linearly polarized laser beam by the power meter 10c may be measured on the reflection side of the Brewster window 10b. In that case, the damper 10d is disposed on the transmission side of the Brewster window 10b.

  In addition to the power meter 10c, a PIN photodiode, CCD, or the like can be applied as long as the output of the linearly polarized laser beam is monitored. In addition to the Brewster window 10b, a polarizer or a diffraction grating can also be applied as an element whose transmittance and reflectance change depending on the polarization direction.

Embodiment 7 FIG.
The laser processing apparatus according to the seventh embodiment further includes a rotational speed detection unit with respect to any one of the laser processing apparatuses according to the first to sixth embodiments described above, and the other embodiments are the same as those of the first to first embodiments. It is the same structure as the laser processing apparatus of the form 6. Accordingly, in the seventh embodiment described below, only the rotation speed detecting means will be described, and the same components as those in the first to sixth embodiments will be denoted by the same reference numerals and the description thereof will be omitted.

  The rotation speed detection means detects the rotation speed of the fiber holding cylinder 7 (polarization plane holding fiber 2). In the present embodiment, the rotation speed of the polarization plane holding fiber 2 is rotated by the control means 5 in the control means 5. 9 is stored in the storage unit 51 based on the control signal to 9.

  In the control means 5, a limit rotational speed that is a limit of twist of the polarization plane holding fiber 2 is stored in the storage unit 51 in advance. And the control means 5 memorize | stored the rotation speed of the fiber holding cylinder 7 (polarization plane holding fiber 2) previously so that the polarization plane holding fiber 2 may not break based on the rotation speed detected by the rotation speed detection means. Suppress below the limit speed.

  As control for suppressing the rotation speed of the fiber holding cylinder 7 (polarization plane holding fiber 2) to be equal to or lower than the limit rotation speed, for example, when the processing is stopped, before the rotation speed of the polarization plane holding fiber 2 reaches the limit rotation speed, The rotation means 6 and 9 are driven to rotate the fiber holding cylinder 7 (polarization plane holding fiber 2) in the direction in which the number of rotations decreases. During processing, the laser oscillator 1, the rotation means 6, 9 and the movement means 8 are stopped to temporarily stop the processing, and the rotation means 6, 9 are driven to reduce the number of rotations. After the (polarization plane maintaining fiber 2) is rotated, the laser oscillator 1, the rotating means 6 and 9, and the moving means 8 are driven again for processing.

  The polarization-maintaining fiber 2 may be broken by a twist exceeding an allowable limit. In this regard, in the laser processing apparatus of the seventh embodiment, it is possible to suppress breakage of the polarization-maintaining fiber 2 by suppressing the rotation speed of the polarization-maintaining fiber 2 to be equal to or lower than the limit rotation speed.

  As described above, the laser processing apparatus according to the present invention is suitable for realizing processing that does not cause anisotropy with linearly polarized laser light with a simple configuration.

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 Polarization plane holding fiber 3 Processing head 31 Fiber holding part 32 Collimator lens 33 Condensing lens 4 Processing table 5 Control means 51 Memory | storage part 6 Rotating means 61 Rotation support part 61a Ball caster 61b Lower ball bearing 61c Upper ball bearing 62 Rotation drive part 62a Rotating shaft 62b Bearing 63 Rotation transmission part 63a Drive gear 63b Driven gear 64 Rotation transmission part 64a Belt 64b, 64c Pulley 7 Fiber holding cylinder 71 Inner cylinder 72 Outer cylinder 73 Positioning part 73a Upper screw hole 73b Lower screw hole 73c Upper shaft adjusting screw 73d Lower shaft adjusting screw 73e Inner wedge type portion 73f Outer wedge type portion 8 Moving means 81, 82 Servo motor 9 Rotating means 91 Hollow portion 91a Support plate 91b Fixing screw 92 Hollow portion drive portion 0 polarization direction detecting means 10a beam splitter 10b Brewster windows 10c power meter 10d damper R light axis W workpiece

Claims (8)

In a laser processing apparatus for processing the workpiece by irradiating the workpiece with laser light,
A processing head provided with a polarization-maintaining fiber that irradiates linearly polarized laser light whose polarization plane is held in a straight line;
A processing table for placing the workpiece irradiated with linearly polarized laser light emitted from the polarization-maintaining fiber; and
Moving means for relatively moving the processing head and the processing table in a two-dimensional direction intersecting the optical axis of the linearly polarized laser beam;
Rotating means for rotating the polarization-maintaining fiber around the optical axis of the linearly polarized laser beam,
Control means for driving the rotating means in accordance with the driving of the moving means and maintaining the polarization direction of the linearly polarized laser beam constant with respect to the relative moving direction of the processing head and the processing table;
A laser processing apparatus comprising:   The laser processing apparatus according to claim 1, wherein the control unit controls driving of the moving unit and the rotating unit based on processing information of the workpiece stored in advance. The rotating means includes
A rotation support unit for rotatably supporting the polarization-maintaining fiber;
A rotation drive unit that causes rotation of the rotation output shaft;
A rotation transmission unit for transmitting rotation of the rotation output shaft of the rotation driving unit to the polarization-maintaining fiber;
The laser processing apparatus according to claim 1, wherein the laser processing apparatus is configured by: The rotating means includes
A hollow portion for inserting and supporting the polarization-maintaining fiber; and
A hollow rotation driving unit that is provided on an outer periphery of the hollow part and rotates the hollow part with the polarization-maintaining fiber;
The laser processing apparatus according to claim 1, wherein the laser processing apparatus is configured by: An inner cylinder for inserting and fixing the polarization-maintaining fiber; and
An outer cylinder that houses the inner cylinder and is fixed to the rotating means;
A position determining unit for moving the position of the inner cylinder in the outer cylinder in a direction intersecting the optical axis of the linearly polarized laser beam, and fixing the inner cylinder in the outer cylinder;
5. An optical axis defining unit configured to match an optical axis of a linearly polarized laser beam emitted from the polarization plane holding fiber with a rotation center of the rotating unit. The laser processing apparatus according to one.   The positioning portion is emitted from the polarization plane holding fiber with the insertion of the inner cylinder into the outer cylinder by the contact between the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder. 6. The laser processing apparatus according to claim 5, wherein an optical axis of the linearly polarized laser beam is made coincident with a rotation center by the rotating means. A polarization direction detecting means for detecting a polarization direction by inputting a part of linearly polarized laser light irradiated from the polarization plane holding fiber to the workpiece;
The laser processing apparatus according to claim 1, wherein the control unit corrects the driving of the rotating unit based on the polarization direction detected by the polarization direction detecting unit. A rotation number detecting means for detecting the rotation number of the polarization-maintaining fiber;
The said control means suppresses the rotation speed of the said polarization plane holding fiber below the limit rotation speed memorize | stored previously based on the rotation speed detected by the said rotation speed detection means. The laser processing apparatus as described in any one of.

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