WO2014038395A1

WO2014038395A1 - Laser processing head

Info

Publication number: WO2014038395A1
Application number: PCT/JP2013/072533
Authority: WO
Inventors: 佐藤　和隆; 俊英加藤; 加藤　博之; 省吾田川; 洋古清水
Original assignee: 株式会社アマダ
Priority date: 2012-09-04
Filing date: 2013-08-23
Publication date: 2014-03-13
Also published as: JP6159513B2; JP2014046361A

Abstract

A laser processing head is provided with: a collimating lens that makes laser light output by an optical fiber output end parallel and linear; a collecting lens that collects the laser light that has been made parallel and linear and outputs the same toward a workpiece; and glass with a wedge that is disposed rotatably between the collimating lens and the collecting lens and has a wedge on one surface thereof.

Description

Laser processing head

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 that is rotatably provided with a glass with a wedge for refracting and decentering the optical axis of laser light 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 laser light. The optical axis is refracted and decentered, and the tilted glass is rotated around the optical axis (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2002-137083

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 of the optical fiber is mounted.

The processing head body 7 is provided with a collimation lens 13 for collimating the laser beam LB emitted from the other end side (exit end) of the optical fiber 9. 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 exit 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 rotates into the gear holder case 23. It is possible to reciprocate 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 connected so as to always be interlocked. The glass holder 21 moves in and out of the optical path of the laser beam LB, that is, the optical axis LA, by reciprocating in the elongated hole.

As is clear 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.

Recently, 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 at a position close to the emission end of the optical fiber 9 as described in Patent Document 1, the inclined glass 19 is damaged. Sometimes.

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 is possible, since the laser beam LB is a parallel beam, the optical axis LB in the laser beam LB cannot be greatly refracted and decentered.

In addition, since the tilted glass has a non-uniform center of gravity, 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 wears 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 problems. According to one aspect of the present invention, a laser processing head collects and irradiates a collimation lens that collimates laser light emitted from an emission end of an optical fiber and collimated laser light on a workpiece. A condensing lens, and a glass with a wedge, which is rotatably disposed between the collimation lens and the condensing lens and has a wedge on one surface.

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. Since the glass with a wedge that refracts and decenters the optical axis in the laser light has a configuration in which one surface is inclined with respect to the optical axis, the optical axis of the laser light is set to a glass plate having both surfaces parallel to the optical axis. Compared to the case of tilting, it can be greatly refracted and decentered.

Also, 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.

FIG. 1 is an elevational sectional view of a laser processing head according to an embodiment of the present invention. FIG. 2 is an elevational sectional view of the laser processing head, and is an enlarged elevational sectional view enlarging the periphery of the imaging means. FIG. 3 is a plan view of a glass with wedges traversing the optical path and means for driving the glass. FIG. 4 is a plan view of a glass with a wedge that traverses the optical path and a means for driving the glass, and shows a state in which the glass holder overlaps the rotating member. FIG. 5 is a plan view of a means for rotating the glass with a wedge and the rotating member integrally. FIG. 6 is an elevational sectional view of a laser processing head according to the prior art.

Several exemplary embodiments of the present invention are described below with reference to the accompanying drawings.

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 an axis. As will be described later, the rotating body 43 is driven and rotated by a motor.

The housing box 45 is integrally provided at the bottom of the bearing box 41 with a fixing tool such as a bolt. In the housing box 45, a condensing lens 47 that condenses the laser beam LB collimated by the collimation lens 39 and irradiates the workpiece W is held by a lens holder 49, and the entire interior is internally provided. Has been.

When condensing the laser beam LB by the condenser lens 47 and irradiating the work W, the glass with a wedge corresponding to the conventional inclined glass 19 is used to refract and decenter the optical axis of the laser beam LB. 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 can rotate 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 drive and rotate 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, by driving the motor 61, the rotating body 43 can be driven and rotated.

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 can be positioned at a position corresponding to the rotating member 55 by rotating the rotating shaft 69, and can be retracted from a position corresponding to the rotating member 55.

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 and decentering 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.

Therefore, 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 that can be engaged and disengaged with respect to the concave portion 59 provided in 55 is provided (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 wedged glass 75 provided in the glass holder 73 is eccentrically rotated. In this way, laser welding of the workpiece can be easily performed by refracting and decentering the optical axis of the laser beam LB and rotating it decenteringly.

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 understood from the above description, the front end side of the support arm 71 provided in the laser processing head 1 according to the present embodiment can enter and exit 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 small energy density, and has a wedge. The glass 75 is not damaged. Even in the region in the laser beam LB that has been collimated by the collimation lens 39, the glass 75 with wedges 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 can be made to. 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 the damage of the surface coating of the glass with the wedge and the breakage of the glass with the 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 can enter and exit the optical path of the laser beam LB.

That is, the housing box 45 is a mirror that is perpendicular to the optical axis of the laser beam LB (a direction perpendicular to the paper surface in FIGS. 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.

An illuminating means 87 for illuminating the imaging position of the CCD camera 81 is provided below the housing box 45. 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, 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 the processing position of the workpiece W is illuminated, a 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.

Although the present invention has been described with reference to preferred embodiments, the present invention is not limited to the above embodiments. Based on the above disclosure, a person having ordinary skill in the art can implement the present invention by modifying or modifying the embodiment.

A laser processing head that effectively prevents damage to glass with a wedge is provided.

Claims

A collimation lens that collimates the laser light emitted from the exit end of the optical fiber;
A condensing lens that condenses the collimated laser beam and irradiates the workpiece;
A glass with a wedge, which is rotatably arranged between the collimation lens and the condenser lens and has a wedge on one surface;
Laser processing head with
The laser processing head according to claim 1,
A support arm that is capable of entering and exiting the tip side with respect to the optical path of the laser light, further comprising a support arm including a glass holder rotatably attached to the tip side;
The glass with wedge is a laser processing head supported by the glass holder.
The laser processing head according to claim 2,
A cylindrical rotating body provided between the collimation lens and the condensing lens so as to be rotatable corresponding to the optical path of the laser beam or a protruding portion protruding radially outward to one of the glass holders;
A laser processing head, further comprising: an abutting member that abuts on the protrusion and rotates integrally with the other of the glass holder or the rotating body.
The laser processing head according to claim 1, 2 or 3,
Protective glass for protecting the condenser lens on the opposite side of the collimation lens with the condenser lens in between,
A ring-shaped illumination means for illuminating the laser processing position through the protective glass;
In order to prevent the illumination light from being directly incident on the imaging means provided above the protective glass, a reflecting cylinder that reflects the illumination light toward the tip of the laser processing head is provided inside the ring-shaped illumination means. And a laser processing head.
The laser processing head according to claim 4,
A reflecting mirror that reflects light from a laser processing position toward the imaging means, and further includes a reflecting mirror arranged so as to be capable of entering and exiting the optical path of the laser light;
The laser processing head, wherein the imaging means is disposed at a height position between the condenser lens and the protective glass and at a position away from an optical path of laser light.
The laser processing head according to claim 4,
A laser processing head, further comprising an air jetting part for blowing out contaminants scattered in the direction of the protective glass to the outside below the protective glass.
The laser processing head according to claim 5,
A laser processing head, further comprising an air jetting part for blowing out contaminants scattered in the direction of the protective glass to the outside below the protective glass.