JP6159513B2 - Laser processing head - Google Patents

Description

  The present invention relates to a laser processing head for performing laser processing such as laser cutting processing or laser welding of the workpiece by condensing and irradiating the workpiece with laser light oscillated from a laser oscillator. The present invention relates to a laser processing head provided with a glass with a wedge for refracting an optical axis of a laser beam when performing laser welding.

  The laser light oscillated from the laser oscillator is guided to a laser processing head using an optical fiber, and the laser light emitted from the output end of the optical fiber is incident on an inclined glass inclined with respect to the optical axis to be emitted as laser light. The axis is refracted and decentered, and the tilted glass is rotated around the optical axis (see, for example, Patent Document 1).

JP 2002-137083 A

  The laser processing head described in Patent Document 1 has the configuration shown in FIG. That is, the laser processing head 1 is attached to the tip of a robot arm 3 in an industrial robot (not shown) via a bracket 5 having an appropriate configuration. The laser processing head 1 includes a cylindrical processing head main body 7 attached to the bracket 5. An optical fiber 9 having one end connected to a laser oscillator (not shown) is connected to the upper portion of the processing head main body 7. An optical fiber holder 11 holding the other end is attached.

  The processing head body 7 is provided with a collimation lens 13 for converting the laser beam LB emitted from the other end side (emission end) of the optical fiber 9 into a parallel beam. A condensing lens 15 that condenses the laser beam LB and irradiates the workpiece W is provided at a position below the collimation lens 13, and a laser nozzle 17 that ejects assist gas to the laser processing position of the workpiece. It has been.

  Between the emission end of the optical fiber 9 and the collimation lens 13, a cylindrical glass holder 21 having an inclined glass 19 inclined with respect to the optical axis LA of the laser beam LB is rotatable in the gear holder case 23. In addition, a reciprocating motion is provided in an arc-shaped elongated hole (not shown) formed in the gear holder case 23. The inclined glass 19 functions to refract and decenter the optical axis LA of the laser beam LB. Accordingly, by rotating the glass holder 21, the optical axis (optical path) LA of the laser beam LB can be eccentrically rotated, and the beam width when performing laser welding can be expanded.

  In order to rotate the glass holder 21, a gear 21G is provided on the outer peripheral surface of the glass holder 21, and a driving gear 27 rotated by a motor 25 attached to the gear holder case 23 is provided on the gear 21G. Meshed. That is, the glass holder 21 and the motor 25 are always linked and connected. The glass holder 21 is provided so as to freely enter and exit the optical path of the laser beam LB, that is, the optical axis LA, by reciprocating in the elongated hole.

  As is apparent from the above configuration, the inclined glass 19 is disposed between the exit end of the optical fiber 9 and the collimation lens 13. Therefore, the diameter of the laser beam LB incident on the inclined glass 19 is small.

  In recent years, a fiber laser has been developed, and this fiber laser is used for laser processing such as laser cutting and laser welding of a metal plate as a workpiece. Since the fiber laser has a high output and a high energy density, if the inclined glass 19 is used in a position close to the emission end of the optical fiber 9 as described in Patent Document 1, the inclined glass 19 is damaged. There is.

  Therefore, when the tilted glass 19 is disposed and rotated between the collimation lens 13 and the condensing lens 15 in a region where the beam diameter of the laser beam LB is large, damage to the tilted glass 19 can be effectively suppressed. Although it was possible, the laser beam LB was a parallel light beam, so that the optical axis LB of the laser beam LB could not be largely refracted.

  In addition, since the center of gravity of the tilted glass is not uniform, when the tilted glass is rotated at a high speed (for example, a speed exceeding 3000 rpm), the part that holds the tilted glass and rotates at the same time as the eccentricity is worn and fretting occurs. Fine metal powder generated by this fretting adheres to the tilted glass, and when the deposited metal powder hits the laser beam, heat absorption occurs, and the surface coating of the tilted glass may be damaged. As a result, there is a problem that the inclined glass itself is damaged due to processing defects and excessive heat.

  The present invention has been made in view of the above-described problems. A collimation lens that collimates the laser light emitted from the exit end of the optical fiber and the collimated laser light is focused on the workpiece. A laser processing head including a condensing lens to be radiated, wherein a glass with a wedge having a wedge on one surface is rotatably provided between the collimation lens and the condensing lens, and is provided in an optical path of the laser light. On the other hand, a support arm whose front end side can freely enter and exit is provided, and a glass holder provided rotatably on the front end side of the support arm is provided with the glass with a wedge, between the collimation lens and the condenser lens, and a laser. One of a cylindrical rotating body or a glass holder that is rotatably provided corresponding to the optical path of light is provided with a projecting portion projecting radially outward, and the glass holder or the rotating The other of the body, is characterized in that it comprises a contact member which is rotated integrally in contact with the protrusion.

In the laser processing head, a protective glass for protecting the condenser lens is provided on the opposite side of the collimation lens with the condenser lens in between, and the laser processing position is illuminated through the protective glass. A ring-shaped illuminating means for irradiating the illuminating light, and in order to prevent direct incidence of the illuminating light on the imaging means provided above the protective glass, the illumination light is provided inside the ring-shaped illuminating means. Is provided with a reflecting cylinder that reflects the laser beam toward the tip of the laser processing head.

  In the laser processing head, the imaging unit is provided at a height position between the condenser lens and the protective glass and away from the optical path of the laser beam, and the image from the laser processing position is captured. A reflecting mirror that reflects in the direction of the means is provided so as to freely enter and exit the optical path of the laser light.

  Further, the laser processing head is characterized in that an air ejection part for blowing out contaminants scattered in the direction of the protective glass to the outside is provided below the protective glass.

  According to the present invention, since the glass with the wedge is rotatably provided between the collimation lens and the condenser lens, the glass with the wedge is arranged in a region where the beam diameter of the laser beam is large, and the wedge is provided. It is possible to effectively prevent damage to the attached glass. The glass with a wedge that performs the refractive decentration of the optical axis in the laser light has a configuration in which one surface is inclined with respect to the optical axis. Therefore, the optical axis of the laser light is set to the glass plate having both surfaces parallel to each other. Compared to the case of tilting, the lens can be largely decentered.

  In addition, the glass with a wedge has less unevenness in the center of gravity than the inclined glass, the occurrence of fretting is small, and damage to the surface coating of the glass with a wedge and breakage of the glass with a wedge can be prevented.

It is a section explanatory view showing the composition of the laser processing head concerning the embodiment of the present invention. FIG. 2 is an enlarged explanatory view in which a configuration of a main part in FIG. 1 is enlarged. It is plane explanatory drawing which shows the structure which puts in / out glass with a wedge with respect to the optical path of a laser beam. It is plane explanatory drawing which shows the structure which puts in / out glass with a wedge with respect to the optical path of a laser beam. It is plane explanatory drawing which shows the structure for rotating the glass with a wedge and a rotation member integrally. It is explanatory drawing which shows the structure of the conventional laser processing head.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to components having the same functions as those of the above-described conventional configuration, and redundant description will be omitted.

  Referring to FIG. 1, a laser processing head 1 according to an embodiment of the present invention is provided at the tip of a robot arm in an industrial robot (not shown), like the conventional laser processing head described above. It is. In addition, since the attachment structure of the laser processing head 1 with respect to the said robot arm may be a general structure, description about the attachment structure of the laser processing head 1 with respect to a robot arm is abbreviate | omitted.

  The laser processing head 1 is provided with a box main body 29, and a lid member 31 is attached to the upper side of the box main body 29 by a fixing tool such as a bolt. A cylindrical lens holder 33 is integrally erected on the upper portion of the lid member 31, and an optical fiber holder 37 holding an end portion of the optical fiber 35 is provided on the upper end portion of the lens holder 33. It is detachable. In the lens holder 33, a collimation lens 39 for converting the laser beam LB emitted from the emission end of the optical fiber 35 into parallel rays is provided.

  A bearing box 41 is integrally attached to the lower surface of the bottom 29B of the box main body 29 by a fixing tool such as a bolt, and a cylindrical rotating body 43 is provided in the bearing box 41 with the light of the laser beam LB. It is provided so as to be rotatable around its axis. The rotating body 43 is rotationally driven by a motor, as will be described later.

  A housing box 45 is integrally provided at a lower portion of the bearing box 41 by a fixing tool such as a bolt. In the housing box 45, a condensing lens 47 that condenses the laser beam LB that has been collimated by the collimation lens 39 and irradiates the workpiece W is provided via a lens holder 49.

  When condensing the laser beam LB by the condenser lens 47 and irradiating the workpiece W, the glass with a wedge corresponding to the conventional tilted glass 19 is used to refract the optical axis of the laser beam LB and rotate it. It is provided in the box body 29. More specifically, the box body 29 is formed in a box shape having an annular peripheral wall 51 as shown in FIG. A vertical through hole 53 is formed in the bottom portion 29B of the box body 29 at a portion coinciding with the optical axis of the laser beam LB, and the cylindrical hole is formed in the through hole 53 portion. A rotating body 43 is rotatably provided.

  A rotating member 55 such as a ring plate that is rotatable in the box body 29 is integrally fixed to the upper end of the rotating body 43 by a fixing tool such as a bolt. Therefore, the rotating member 55 can be regarded as a part of the rotating body 43. As shown in FIG. 3, the rotating member 55 includes a plurality of projecting portions 57 projecting radially outward, and a recess 59 is disposed between the projecting portions 57. In order to rotationally drive the rotating body 43, an endless belt 65 that is wound around a driving pulley 63 of a motor 61 provided at an appropriate position of the laser processing head 1 is wound around the rotating body 43. Therefore, the rotating body 43 can be rotationally driven by driving the motor 61.

  A rotation actuator 67 (see FIG. 1) such as a motor is mounted on the lid member 31 of the box body 29, and a support arm is attached to a rotation shaft 69 (see FIG. 3) of the rotation actuator 67. The base end side of 71 is fixed integrally. The distal end side of the support arm 71 is configured to be able to be positioned to a position corresponding to the rotating member 55 and to be retracted from a position corresponding to the rotating member 55 by rotating the rotating shaft 69.

  In other words, the distal end side of the support arm 71 is configured to be able to enter and exit the optical path of the laser beam LB. A ring-shaped glass holder 73 rotatably supported by a through hole portion formed on the distal end side of the support arm 71 has a wedged glass 75 for refracting the optical axis of the laser beam LB. Is provided. In the glass 75 with a wedge, one surface of the upper surface or the lower surface is formed on a surface inclined with respect to the optical axis (surface with a wedge), and the other surface is formed on a plane perpendicular to the optical axis. It is.

  Accordingly, when the laser beam LB is incident on the wedged glass 75, the optical axis of the laser beam LB is refracted and decentered. Therefore, when the wedged glass 75 is rotated, the optical axis of the laser beam LB is eccentrically rotated.

  As shown in FIG. 3, the wedged glass 75 is retracted from the optical path of the laser beam LB, that is, the support arm 71 is in contact with the stopper 77, and the wedged glass 75 is separated from the rotating member 55. In some cases, the laser beam LB that has been collimated by the collimation lens 39 passes through the rotating member 55 and is directly incident on the condenser lens 47. Accordingly, the laser beam LB emitted from the emission end of the optical fiber 35 is converted into parallel rays by the collimation lens 39 and travels straight, and is collected by the condenser lens 47 and applied to the workpiece W. Therefore, laser cutting of the workpiece W is performed.

  When the support arm 71 is rotated clockwise from the state shown in FIG. 3 and the distal end side of the support arm 71 enters the optical path of the laser beam LB, the glass holder provided on the distal end side of the support arm 71. 73 is positioned so as to overlap the rotating member 55 (see FIG. 4). As described above, when the rotating member 55 and the glass holder 73 are positioned so as to overlap with each other, the rotating member 55 and the glass holder 73 are integrally rotated with the rotating member 55. An engaging member 79 is provided that can be engaged and disengaged with respect to the recess 59 provided in 55 (see FIGS. 3 and 5).

  Therefore, when the rotating member 55 is rotated while the engaging member 79 is engaged with the recess 59, the glass holder 73 is rotated via the engaging member 79. Therefore, the laser beam LB whose optical axis is refracted and decentered by passing through the glass 75 with a wedge provided in the glass holder 73 is eccentrically rotated. In this way, the laser beam of the workpiece can be easily laser-welded by refracting the optical axis of the laser beam LB and rotating the laser beam LB eccentrically.

  By the way, since the positional relationship between the rotating member 55 and the engaging member 79 is relative, the glass holder 73 includes the rotating member 55 and the rotating body 43 includes the engaging member 79. Is also possible. In the above description, a case has been described in which the rotating member 55 is provided with a plurality of protrusions 57 so that the recess 59 is provided. However, only one protrusion 57 may be provided. In this case, the engaging member 79 is integrally pressed and rotated by coming into contact with the protruding portion 57, so the engaging member 79 can also be called a kind of abutting member or a pressed member. It is.

  As can be understood from the above description, the distal end side of the support arm 71 provided in the laser processing head 1 according to the present embodiment can freely enter and leave the optical path of the laser beam LB. And since it is the structure which provided the glass 75 with a wedge rotatably at the front end side of this support arm 71, the laser processing head 1 which concerns on this embodiment can be used for both a laser cutting process and a laser welding. It can be done. When the wedged glass 75 is positioned in the optical path of the laser beam LB, the laser beam LB is collimated by the collimation lens 39 between the collimation lens 39 and the condensing lens 47. Therefore, the diameter of the laser beam LB is large.

  Therefore, even if the laser beam LB is a fiber laser and is a high-power laser beam LB, the laser beam LB incident on the wedged glass 75 has a large diameter and a low energy density, and has a wedge. The glass 75 is not damaged. Even in the region within the laser beam LB that has been converted into parallel rays by the collimation lens 39, the wedged glass 75 is a glass whose both surfaces are non-parallel, so that the optical axis of the laser beam LB is effectively refracted and decentered. It is something that can be done. Further, the glass with a wedge has less unevenness of the center of gravity than the inclined glass, the occurrence of fretting is small, and damage to the surface coating of the glass with a wedge and breakage of the glass with a wedge can be prevented.

  In the laser processing head 1, an image pickup means 81 such as a CCD camera for picking up an image of the laser processing position is provided on the side surface of the housing box 45. A reflecting mirror that reflects light from the laser processing position of the workpiece W toward the CCD camera 81 is positioned below the condenser lens 47 in the housing box and corresponding to the CCD camera 81. 83 is provided. The reflecting mirror 83 is provided so as to freely enter and exit the optical path of the laser beam LB.

  That is, in the housing box 45, a mirror that is perpendicular to the optical axis of the laser beam LB (a direction perpendicular to the paper surface in FIGS. 1 and 2) and is freely movable in and out of the housing box 45. An entrance / exit slider 85 is provided, and the reflecting mirror 83 is inclined and provided on the mirror entrance / exit slider 85. The mirror entry / exit slider 85 is reciprocated by the operation of an appropriate linear actuator (not shown) such as a linear motor or a fluid pressure cylinder.

  As understood from the above configuration, the reflecting mirror 83 is retracted from the optical path of the laser beam LB when the workpiece W is irradiated with the laser beam LB to perform laser processing. Then, when the machining position is imaged by the CCD camera 81, it is moved and positioned in the optical path of the laser beam LB so as to correspond to the CCD camera 81. Therefore, the portion subjected to the laser processing by irradiating the laser beam LB can be imaged by the CCD camera 81, and the laser processing state after the laser processing can be observed.

  Below the housing box 45, there is provided illumination means 87 for illuminating the imaging position of the CCD camera 81. A protective glass 89 that protects the condenser lens 47 from sputtering and the like scattered from the irradiation position of the laser beam LB is provided below the illumination unit 87. More specifically, an annular illumination housing 91 is integrally attached to the lower surface of the housing box 45 by a fixture such as a bolt.

  In the illumination housing 91, for example, a ring-shaped light source 95 provided with a plurality of point light sources 93 such as LEDs on the same circle is provided. The illumination housing 91 is provided with a light shielding member 97 in order to prevent illumination light irradiated from the respective point light sources 93 toward the center from directly entering the reflecting mirror 83. The light shielding member 97 is formed in a tapered cylindrical body having a small diameter on the lower side, and is provided inside the ring-shaped light source 95.

  The lower end portion of the cylindrical light shielding member 97 is located below the point light sources 93. An annular light reflecting surface 99 for reflecting the illumination light from the point light source 93 toward the tip end side (downward in FIGS. 1 and 2) of the laser processing head is provided on the outer peripheral surface of the light shielding member 97. . Therefore, the illumination light from each point light source 93 is reflected only downward (on the tip side of the laser processing head) by the light reflecting surface 99 of the light shielding member 97.

  The protective glass 89 is held by a ring-shaped glass holder 101 that is detachably provided on the lower surface of the illumination housing 91, and is disposed close to the lower end of the light shielding member 97. The glass holder 101 is provided with an optical fiber 103 as a dirt detecting means for detecting dirt on the protective glass 89.

  Therefore, when the illumination light from each point light source 93 is applied to the protective glass 89 and is reflected by the portion of the dirt substance adhering to the protective glass 89, the light propagates through the protective glass 89 and passes through the optical fiber 103. It will be incident on the end. Therefore, when the amount of dirt attached to the protective glass 89 increases and the detection value of the optical sensor connected to the optical fiber 103 becomes larger than a preset reference value, the protective glass 89 is replaced.

  As already understood, when the processing position is illuminated by each point light source 93 in order to image the processing position by the CCD camera 81, the reflected light from the processing position is reflected by the reflecting mirror 83 positioned in the optical path by the CCD. Reflected in the direction of the camera 81, the processing position is imaged. At this time, the irradiation light from each point light source 93 is reflected downward by the annular light reflecting surface 99 provided on the outer peripheral surface of the light shielding member 97, passes through the protective glass 89, and is irradiated to the processing position of the workpiece W. Will be.

  As described above, when illuminating the processing position of the workpiece W, part of the illumination light is reflected by the upper surface of the protective glass 89. However, since the lower end portion (tip portion) of the light shielding member 97 and the protective glass 89 are close to each other, the reflected light from the upper surface of the protective glass 89 is prevented from entering the reflecting mirror 83. Therefore, a phenomenon in which reflected light from the upper surface of the protective glass 89 is incident upon imaging by the CCD camera 81 and the screen is blurred in white, that is, halation can be prevented, and the processing position of the workpiece W can be imaged clearly. is there.

  As described above, when illuminating the processing position of the workpiece W, when the illuminating light of each point light source 93 is transmitted through the protective glass 89, if the contaminant such as spatter adheres to the protective glass 89, this dirty substance portion Part of the reflected light irregularly reflected by the light propagates through the protective glass 89 and is incident on the end of the optical fiber 103, whereby the contamination of the protective glass 89 can be detected.

  In order to prevent contaminants such as spatter scattered from the laser processing position from adhering to the protective glass 89, the contaminants that tend to adhere to the protective glass 89 are blown off under the protective glass 89. The air jet housing 105 (see FIG. 1) is provided, and a laser nozzle 107 is detachably attached to the lower portion of the air jet housing 105.

  More specifically, the air ejection housing 105 is provided in the laser processing head 1 via a fixture such as a bolt, for example, and the air ejection housing 105 is arranged with respect to the optical axis of the laser beam LB. And an opening 109 that opens in a direction orthogonal to the right side (the right side in FIG. 1). The lower part of the air ejection housing 105 is provided with an air ejection part 111 for blowing contaminants scattered from the processing part of the workpiece W toward the condenser lens 47 to the outside along the opening 109. ing.

  Therefore, when performing laser processing by irradiating the workpiece W with the laser beam LB, contaminants such as spatter scattered from the laser processing position toward the condenser lens 47 are blown out to the outside by the air blown from the air blowing portion 111. It is. Therefore, contaminants adhering to the protective glass 89 can be suppressed.

  As understood from the above description, according to the above configuration, when the laser processing position is illuminated by each point light source 93 when the laser processing position is imaged by the CCD camera 81 provided in the laser processing head 1, protective glass is used. It is possible to prevent halation from being reflected by the reflected light from 89 and to clearly image the laser processing position. Moreover, according to the said structure, while being able to detect the stain | pollution | contamination of the protective glass 89, adhesion of the dirt substance with respect to the protective glass 89 can be suppressed.

DESCRIPTION OF SYMBOLS 1 Laser processing head 35 Optical fiber 39 Collimation lens 43 Rotating body 47 Condensing lens 55 Rotating member 57 Protrusion part 59 Concave part 71 Support arm 73 Glass holder 75 Glass with wedge 79 Engagement member (contact member, pressed member)
81 Imaging means (CCD camera)
83 Reflecting mirror 85 Mirror entry / exit slider 87 Illumination means 89 Protective glass 91 Illumination housing 93 Point light source (LED)
95 Ring-shaped light source 97 Light shielding member 99 Light reflecting surface 101 Glass holder 103 Dirt detection means (optical fiber)
105 Air blowout housing 109 Opening 111 Air blowout

Claims (4)

  A laser processing head comprising: a collimation lens that collimates laser light emitted from an emission end of an optical fiber; and a condensing lens that collects the collimated laser light and irradiates the workpiece. Between the collimation lens and the condensing lens, a glass with a wedge with a wedge on one surface is rotatably provided, and a support arm is provided that allows the front end side to enter and exit the optical path of the laser light. A cylindrical rotation provided in the glass holder rotatably provided on the tip side, provided with the glass with a wedge, and rotatably provided corresponding to the optical path of the laser light between the collimation lens and the condenser lens. One of the body and the glass holder is provided with a projecting portion projecting radially outward, and the other of the glass holder or the rotating body is in contact with the projecting portion and rotated integrally. Laser processing head, characterized in that it comprises a contact member. 2. The laser processing head according to claim 1, further comprising a protective glass for protecting the condensing lens on the opposite side of the collimation lens with the condensing lens in between, and transmitting the protective glass to perform laser processing. A ring-shaped illuminating means for illuminating the position is provided, and in order to prevent direct incidence of the illuminating light on the imaging means provided above the protective glass, inside the ring-shaped illuminating means A laser processing head comprising a reflecting cylinder that reflects illumination light toward the tip of the laser processing head.   3. The laser processing head according to claim 2, wherein the imaging unit is provided at a height position between the condenser lens and the protective glass and separated from the optical path of the laser light, and the light from the laser processing position is provided. A laser processing head comprising: a reflecting mirror that reflects light in the direction of the imaging means so as to freely enter and exit the optical path of the laser light.   The laser processing head according to claim 2 or 3, further comprising an air ejection portion for blowing out contaminants scattered in the direction of the protective glass on the lower side of the protective glass. head.

Images