DE102011117454B4 - Laser processing device - Google Patents

Abstract

Laser processing device for processing components (9) with - a laser processing head (10), - a holder (14) for the laser processing head (10), which can be attached to an industrial robot in order to guide the laser processing head along a processing line, - a pressure element that is attached to the holder (14) in order to clamp the components (9) during processing, the laser processing head (10) having a housing through which a working beam path (23) for a laser beam (18) is guided and in which a collimator unit (41) with collimator optics (50) which collimate the laser beam (18) emerging from an optical fiber (24), a pendulum mirror unit (42) with a rotatably mounted mirror (25) and a rotary drive unit (51), a focusing optic (26 ) which focus the laser beam (18) in an interaction zone (19) between the laser beam (18) and the components (9) to be machined, - the mirror (2 5) is arranged rotatably in the collimated working beam path (23) that the focal position of the laser beam (18) in the interaction zone (19) can be displaced transversely to the optical axis (29) of the focusing optics (26), and - by means of the rotary drive unit (51) the mirror (25) is adjustable so that the focus position follows the processing line, - a mirror control circuit is provided to control the rotational movement of the mirror (25), which is designed so that a deflection signal for following the processing line periodic, high-frequency deflection signal can be superimposed to widen a machining track, - the mirror (25) about a first and a second axis of rotation (30; 33) is rotatable, and wherein the two axes of rotation (30; 33) intersect with one another in such a way that their point of intersection coincides with the optical axis (29) of the focusing optics (26).

Description

The invention relates to a laser processing device for processing components. In particular, the invention relates to a laser processing device for soldering, welding and / or cutting, in particular for welding and / or cutting sheet metal components arranged in two or more layers by means of laser radiation and for powder deposition welding.

From the EP 0 892 692 B1 a welding device for welding and / or cutting is known which has a laser processing head, a guide device and at least one pressure roller as a pressure element for clamping the components to be processed during processing. The guide device can be fastened by means of a holder to the hand of a manipulator, that is to say of an industrial robot of whatever configuration. In order to be able to handle the known welding device more flexibly and better, it is provided that the guide device has an adjusting device which is movable in one or more axes and with which the laser processing head can be adjusted relative to the pressure roller.

By means of the adjusting device, the laser head can thus be shifted, in particular transversely or obliquely to the track being followed, so that it is possible to correct the path movement of the laser processing head based on the actual position of the weld or cut seam using a seam detector. For this, however, very fast movements are required, which, due to the large mass of the laser processing head, makes correspondingly complex drives for the actuating device necessary. However, rapid movements are not possible if the moving mass is large, as is the case when moving the entire laser head.

From the DE 10 2004 007 178 A1 a laser processing head is known with a housing through which a working beam path for the laser beam is guided. An imaging mirror is provided as the focusing optics, which focuses the incident laser beam into a working focus that is provided outside the housing at a distance from it. In order to enable a scanning or scanning movement of the working focus 1 in the known laser processing head, provision is made for the focusing optics to be rotatable about an axis of rotation which is coaxial with the optical axis of the incident working beam path.

DE 10 2004 010 483 A1 describes a laser welding device with a laser head with a laser light source, a movable deflecting mirror and a focus system. A laser beam emitted by the laser light source is first deflected by the movable deflecting mirror, then focused by the focus system and directed onto body parts that are held in position with a clamping device. The deflection mirror can be equipped with two separately controllable motors in order to deflect the laser beam in a working plane.

DE 10 2010 029 477 A1 describes a device for laser joining of sheet metal parts. The device has clamping means for clamping the sheet metal parts to be joined and a beam guiding device for a laser beam. The beam guiding device has at least one swivel mirror, via which the laser beam is guided to a processing point.

DE 10 2009 051 715 A1 describes a machining head for machining workpieces. An optical unit is arranged in the processing head, by means of which a laser beam can be positioned and focused on the workpiece. The optical unit comprises two mirrors and an optical lens. The mirror can be used to deflect the laser beam for exact positioning, with the optical lens focusing a laser beam directed onto the workpiece.

EP 1 005 944 A2 describes a laser beam welding process for lap seams. To carry out the welding process, a focusing mirror can be moved transversely to a weld seam.

EP 1 716 963 A1 describes an optical arrangement in which a deflection system comprises at least one rotatably mounted mirror and a drive for the angle adjustment of the mirror.

DE 196 41 125 A1 describes an electrolysis apparatus for the production of halogen gases. A laser beam welding process is used in the manufacture of the electrolysis apparatus. A common seam shape is produced by high-frequency scanning of a focusing mirror with an amplitude of, for example, 0.5 mm.

DE 103 55 051 A1 describes a device for laser beam welding, in which the weld seam is widened by superimposing the feed movement of the laser beam with a local lateral movement component.

DE 10 2004 043 076 A1 describes a method for monitoring a laser beam machining process of a welding head, in which, when there is a gap between the workpieces to be joined, the laser beam is guided in a pendulum motion.

The invention is based on the object of providing a laser processing device in which a working focus of a laser beam is simple Way can be moved relative to a clamping element that clamps the components to be machined.

This object is achieved by the laser processing device according to claim 1. Advantageous refinements and developments of the invention are described in the subclaims.

According to the invention, a rotatable mirror is arranged in the working beam path of a laser processing head, which can be guided along a processing line by an industrial robot together with a pressure element, in particular a pressure roller, so that the working focus generated by the focusing optics due to the rotating movement of the mirror, in particular transversely to Feed movement of the laser processing head and pressure roller, which can be moved for precise seam tracking. This means that significantly faster movements of the laser focus (tool center point TCP) are now possible than in the prior art described at the beginning, since the moving mass is reduced to a light mirror. This results in the advantage that faster deflection movements of the TCP are possible transversely to the trajectory, that is to say to the movement path of the laser processing head and pressure element.

Due to the comparatively low mass of the rotatable mirror, very rapid deflection movements of the working focus can be carried out, so that precise tracking of the processing line can be achieved even at high processing speeds.

Although it is basically possible, especially with long focal lengths, to mount the movable mirror in the laser beam direction behind the focusing optics, an advantageous embodiment of the invention provides that the mirror is arranged in front of the focusing optics as seen in the laser beam direction. It is thus protected from contamination inside the laser processing head.

It is particularly advantageous if the mirror can be rotated about an axis of rotation lying in the mirror plane. This enables a particularly simple actuation of the mirror. The axis of rotation is to be arranged in such a way that it intersects the optical axis of the focusing optics.

In order to achieve a particularly flexible shift of the focus position of the laser beam in the interaction zone, it is provided that the mirror can be rotated about a first and a second axis of rotation, and that the two axes of rotation intersect with each other so that their intersection point with the optical axis of the focusing Optics coincide. The second axis of rotation has the same function as a scanner, resulting in an additional deflection of the TCP in the feed direction.

To implement the widening of a machining track, it is useful if a mirror control circuit is provided to control the rotational movement of the mirror, which is designed so that a periodic, high-frequency deflection signal for widening the machining track is superimposed on a deflection signal for tracking a machining line, i.e. modulated. A very rapid periodic deflection movement can therefore be superimposed on the deflection movement of the working focus for tracking the machining line, so that the effective machining track has a greater width than the working focus itself.

In this way, a processing line, in particular a joining line or joining seam, can also be machined with a small, precise work focus, even if a gap between the workpieces to be joined is wider than the work focus. In particular, if the seam tracking device detects not only the actual position of the machining line, but also, if necessary, the width of a gap between the components to be joined, it is also possible to guide the work focus in such a way, i.e. to allow it to oscillate, that it also varies a tolerance-related gap Gap width covers. Reliable machining, in particular reliable joining or welding of components to be connected to one another, can thus be achieved even with large tolerances.

• 1 eine vereinfachte schematische Darstellung einer Laserbearbeitungsvorrichtung;
• 2 eine stark vereinfachte schematische Darstellung des Grundprinzips der vorliegenden Erfindung;
• 3 einen Laserbearbeitungskopf gemäß der vorliegenden Erfindung;
• 4 eine schematische Darstellung einer Ausführungsvariante des Arbeitsstrahlengangs in einem Laserbearbeitungskopf gemäß der vorliegenden Erfindung; und
• 5 ein Diagramm zur Erläuterung der Arbeitsweise einer erfindungsgemäßen Bearbeitungsvorrichtung.

The invention is explained in more detail below, for example with reference to the drawing. Show it:

• 1 a simplified schematic representation of a laser processing device;
• 2 a greatly simplified schematic representation of the basic principle of the present invention;
• 3 a laser machining head according to the present invention;
• 4th a schematic representation of an embodiment variant of the working beam path in a laser processing head according to the present invention; and
• 5 a diagram to explain the operation of a machining device according to the invention.

In the various figures of the drawing, elements and components that correspond to one another are provided with the same reference symbols.

As in 1 shown, comprises a laser processing device for processing Components, here of sheet metal components arranged in two layers 9 , a laser processing head 10 and a pressure roller as a pressure element 11 on that together with the laser processing head 10 for joint movement with this on a mounting plate 12th a bracket 14th is appropriate. Instead of the in 1 mounting plate shown 12th Another suitable component can also be provided which ensures that the laser processing head 10 and pressure roller 11 precisely maintain their set spatial position relative to one another when moving along a machining line. The mounting plate 12th can be attached directly to the hand of an industrial robot or with the interposition of an adjustment device 15th with which the position of the laser processing head 10 and pressure roller 11 can be adjusted in relation to the hand of an industrial robot (not shown). The adjustment device 15th is via another mounting element 16 and a connecting flange 17th attachable to the hand of the industrial robot.

One from the laser processing head 10 emerging laser beam 18th is applied to the workpiece or component 9 focused that his work focus is defined in the interaction zone 19th between laser beam 18th and workpiece 9 lies.

As in 2 is shown in simplified schematic form, has a laser processing head 10 a housing 20th with an inlet port 21 and an outlet port 22nd on, through which a working beam path 23 for the laser beam 18th is led. In the inlet port 21 is an optical fiber 24 with its outlet end for the laser beam 18th appropriately arranged. The one from the optical fiber 24 emerging laser beam 18th becomes on one in the working beam path 23 arranged deflection mirror 25th directed the laser beam 18th in the direction of focusing optics 26th that redirects the laser beam 18th into a work focus 28 focused in the desired manner in the area of the interaction zone 19th on the workpiece 9 hits. To shift the focus of work 28 across the optical axis 29 the focusing optics 26th to enable is the deflection mirror 25th for example around an axis 30th rotatable, as indicated by the double arrow 31 is indicated. The axis 30th stands in the illustrated embodiment in 2 perpendicular to the plane of the drawing and intersects the optical axis 29 . A twisting motion of the mirror 25th around the axis of rotation 30th according to the double arrow 31 causes the working focus to be shifted to the right or left in 2 , as indicated by the linear double arrow 32 is indicated. Particularly when using focusing optics with a long focal length, it is possible to arrange a rotating or pendulum mirror behind the focusing optics for beam deflection and thus for shifting the working focus or TCP.

Alternatively or additionally, the mirror can 25th also about an axis of rotation lying in the plane of the drawing 33 be rotated, as indicated by the double arrow 34 indicated. Such a rotary movement has a shift in the working focus 28 in the direction perpendicular to the plane of the drawing.

But it is also conceivable, the mirror 25th in order to be able to rotate or pivot a pivot and pivot axis arranged at its edge in a manner not shown in detail. Even with such an arrangement there is a shift in the working focus 28 across the optical axis 29 possible.

The laser processing device is now used for processing a workpiece or component 9 along a machining line, e.g. along a joint 34 in 5 out, for example, the pressure roller runs 11 for clamping the workpiece or component 9 along a line 35 essentially parallel to the joint 34 while the work focus 28 by laterally adjusting its position relative to the optical axis 29 the focusing optics 26th along the joint or joint line 34 as shown in the lower part of 5 through the double line 34 , 36 is indicated. If the machining line or seam 34 requires a wider work focus than the laser beam 18th with his work focus 28 can provide, so can the relatively slow rotational movement of the deflection mirror 25th For seam tracking, a very fast periodic rotary movement with a deflection corresponding to the desired seam width can be superimposed, so that the work focus 28 follows a periodic, for example sinusoidal, track, the zero crossings of which essentially coincide with the joint to be followed.

3 shows another laser processing head 10 , which is a collimator unit 41 , a rotating or pendulum mirror unit 42 , a deflecting mirror unit 43 and a focusing unit 44 having. A line generator is used to implement seam tracking in real time 45 provided, for example by means of a light fan 46 a line of light 47 on the workpiece 9 across the processing line or joint in front of the interaction zone 19th generated. The line of light 47 is, as will be explained in more detail later, observed by means of a camera in order to receive regulation or control signals for the position of the working focus 19th so that it exactly follows the recorded, actual machining line or joint.

As in 4th shown is in the working beam path 23 of a laser processing head 10 corresponding 3 in the area of the collimator unit 41 a collimator optics 50 provided that the from the optical fiber 24 emerging laser beam 18th collimated. The parallel laser beam 18 ' is then on a deflection mirror 25th steered, which, as based on 2 has been explained can be rotated about one or two axes of rotation. The rotating or pendulum mirror unit 42 points to the rotation of the deflecting mirror 25th a rotary drive unit 51 on that the deflector mirror 25th around one or two axes of rotation so that the working focus 28 the machining line or joint 34 ( 5 ) precisely follows. The parallel laser beam 18 ' is from the pivoted deflector mirror 25th onto another deflecting mirror 52 the mirror unit 43 steered and from this then to the focusing optics 26th which reflects the parallel laser beam 18 ' in the work focus 28 focused (convergent laser beam 18th ). Because here the collimated laser beam on the deflecting mirror 25th and the other deflecting mirror 52 is directed, the reflective layer of the mirror can be produced more easily than for a mirror that has to deflect a divergent laser beam.

There is a camera for process monitoring and seam tracking 53 with a lens 54 and a radiation-sensitive receiver arrangement 55 provided, the radiation from the interaction area 19th and its surroundings, especially radiation from the light line 47 for seam tracking through the focusing optics 26th and the deflecting mirror which is essentially transparent to this radiation 25th captured through. The output signals of the radiation-sensitive receiver arrangement 55 are sent to an evaluation circuit for further processing, in particular for process monitoring and seam tracking 56 delivered. The evaluation circuit 56 supplies via the control signal output 57 the control signals for the rotary actuator 51 that this above the signal input 57 are fed.

To control the rotation of the mirror 25th is a mirror control circuit in the evaluation circuit 56 provided, which is designed so that a deflection signal for following a machining line can be superimposed with a periodic, high-frequency deflection signal for widening a machining track.

About other process parameters, such as the power of the laser beam 18th can be monitored by additional sensor modules 58 be provided, such as between the collimator unit 41 and the pendulum mirror unit 42 is indicated by dashed lines.

The laser processing head is now used when processing 10 together with the pressure roller 11 guided along the processing line, the pressure roller 11 next to the actual machining line or joint 34 (please refer 5 ) along the line 35 is guided, the position of the seam, that is to say the position of the joint to be joined in front of the processing point, is determined with a suitable seam detection device, for example with the aid of a line generator 45 generated light line captured, which is expedient way with a camera 53 he follows. Due to the detected deviation of the actual position of the joint 34 The deflection mirror, designed as a rotating or pendulum mirror, is then derived from the programmed joining line 25th with the help of the rotary drive 51 operated so that the work focus 28 relative to the optical axis 29 the focusing optics 26th is adjusted so that it exactly matches the actual joint line 34 follows.

As explained above, the control signal for the rotatable deflecting mirror can also be used here to widen the processing line 25th a high-frequency signal with a small amplitude can be superimposed or modulated, so that an apparent broadening of the working focus 28 is present.

Usually the work focus 28 with the help of the rotatable deflection mirror 25th adjusted so that its distance from the pressure point of the pressure roller 11 according to the joint 34 varies.

According to the invention, the work focus can thus 28 exactly along an actual machining line 34 or join seam without large masses having to be moved within the laser processing device. In this way, precise guidance of the working focus along a processing line, in particular along a seam to be joined, can be carried out in a simple manner.

Claims (4)

Laser processing device for processing components (9) with - a laser processing head (10), - a holder (14) for the laser processing head (10), which can be attached to an industrial robot in order to guide the laser processing head along a processing line, - a pressure element that is attached to the holder (14) in order to clamp the components (9) during processing, the laser processing head (10) having a housing through which a working beam path (23) for a laser beam (18) is guided and in which one Collimator unit (41) with collimator optics (50) which collimate the laser beam (18) emerging from an optical fiber (24), a pendulum mirror unit (42) with a rotatably mounted mirror (25) and a rotary drive unit (51), a focusing optic ( 26), which focus the laser beam (18) in an interaction zone (19) between the laser beam (18) and the components to be processed (9), - the Spi egel (25) is arranged rotatably in the collimated working beam path (23) that the focus position of the laser beam (18) in the Interaction zone (19) is displaceable transversely to the optical axis (29) of the focusing optics (26), and - the mirror (25) being adjustable by means of the rotary drive unit (51) so that the focus position follows the processing line, Rotational movement of the mirror (25) a mirror control circuit is provided, which is designed so that a deflection signal for tracking the processing line, a periodic, high-frequency deflection signal for widening a processing track can be superimposed, - the mirror (25) by a first and a second The axis of rotation (30; 33) is rotatable, and wherein the two axes of rotation (30; 33) intersect with one another in such a way that their point of intersection coincides with the optical axis (29) of the focusing optics (26). Laser processing device according to Claim 1 , wherein the mirror (25) is rotatable about an axis of rotation (30; 33) lying in the mirror plane. Laser processing device according to one of the Claims 1 or 2 wherein a deflecting mirror unit (43) with a deflecting mirror (25) is arranged between the pendulum mirror unit (42) and the focusing optics (26), which is essentially transparent to radiation from the interaction zone (19). Laser processing device according to one of the preceding claims, wherein the pressure element is a pressure roller (11).

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