JP3060779B2 - Laser processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for irradiating a workpiece with a laser beam and performing laser processing such as welding.

[0002]

2. Description of the Related Art In laser processing, a small beam spot of high energy formed by condensing a laser beam is irradiated from a laser processing head toward a workpiece .
By doing this, various processes such as welding, cutting, drilling, etc. are performed, and high-precision processing can be realized relatively easily, and it has the advantage that the thermal effect on the workpiece is small. It is often used because it is.

[0003] Laser processing head which is conventionally used in the laser machining apparatus, for example, is shown in FIGS. 1 4. 1 4, the laser processing head 101,
Attached to a movable robot arm (not shown)
By teaching the robot, the laser processing head 101 is moved along a predetermined moving path.

The laser processing head 101 collects a laser beam B oscillated from a laser oscillation source (not shown) by a condenser lens 3 attached to an end of a main body 2.
A reflecting mirror 4 is mounted on the optical axis T1 of the condenser lens 3, and reflects the laser beam B condensed by the condenser lens 3 toward the nozzle portion 6, and forms a focal point F outside the nozzle portion 6. It has become.

At the position of the focal point F, welding is performed by irradiating the welded portion of the work W. It is important that the welding position of the work W is accurately aligned with the focal position of the laser beam B. Since the laser beam B has the same phase as that of ordinary light and has a property of extremely high light condensing property, the focal length for minimizing the spot diameter of the condensed laser beam B is: The allowable range is narrow and deviates from the allowable range with a slight deviation.

In the conventional condenser lens 3, the allowable range is very narrow, that is, within ± 0.3 mm.
In the case of performing the teaching (1), visual position adjustment is not sufficient, and accurate positioning has not always been possible.

For this reason, conventionally, as shown in FIG. 15 , the amount of the gap between the nozzle portion 6 and the work W is adjusted using a jig 5 for adjusting a so-called ski gage or the like, and the laser The position of the processing head 101 is taught to a robot controller or the like of the welding robot. As another example of a conventional laser processing head, for example, those shown in FIG. 16. Laser processing head 102 shown in FIG. 16
The laser beam reflected by the final mirror 7 is reflected and condensed by the parabolic mirror 8 for processing.

[0008]

However, FIG.
In the former laser processing head 101 shown in (1), even if the position of the nozzle portion 6 is adjusted using the jig 5 for adjusting the glance gauge or the like, a deviation of about ± 0.5 mm usually remains at the teaching position. . In particular, depending on the welding position, the position of the nozzle portion 6 of the laser processing head 101 whose position is adjusted may not be directly visible, and the teaching operation is extremely difficult.

[0009] liked seeing gauge such as an insufficient position adjustment be used, when the position accuracy of the teaching position is also not enough, after adjustment that by the love watching gauge, actually performs a trial welding of work, resulting determining the quality of welding from the state of the bead, the position of the laser processing head by which are finely adjusted to be more optimal position.

However, when the test welding is performed, the time required for teaching becomes very long, and the number of times of the test welding is also increased.
From that not need in one at a time teaching, the time required for this teaching will be even longer,
The burden of teaching work is further increased. In addition, the trial welding has a disadvantage that a work for the trial welding is required.

Further, even if the focal length of the condenser lens 3 is processed to have the same focal length, there is a variation in each individual lens. teaching work of the machining head is, as a rule Ji must be raw to be performed for each laser processing head, is supposed to take a multi-large amount of time to teaching work.

The latter laser processing head 10 shown in FIG .
In 2, it is necessary to adjust a plurality of mirrors (not shown) provided in advance to determine whether the optical path before the final mirror 7 matches. That is, as shown in FIG. 17 , a semi-transparent mirror 9 is attached in place of the parabolic mirror 8 to check the optical path, and a guide He- provided for advance adjustment.
The adjustment is performed by adjusting the position of the spot generated on the translucent mirror 9 even if the position of the Ne laser is moved in various directions. However, in this case, the final mirror 7
This adjustment work is also troublesome because a plurality of mirrors provided before the camera must be adjusted. After adjusting the optical path using the He-Ne laser for guiding, a parabolic mirror 8 is attached, and a C
It is necessary to perform processing by operating an O2 laser to check whether predetermined processing is performed.
In the case of e-laser and CO2 laser, an error may occur between the two, and in some cases, readjustment is necessary.
It made it there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides a laser processing apparatus capable of performing teaching work for teaching a moving path of a laser processing head more easily, accurately, and in a short time. The purpose is to:

[0014]

According to a first aspect of the present invention, there is provided a light-collecting device which is irradiated from an output source.
The laser beam focused by the step is reflected by the reflecting member
And a laser processing head that the reflected laser beam to irradiate a workpiece, the optical axis of the reflected laser beam
Are arranged around the edge of the work
Irradiate the measurement laser beam obliquely to the workpiece
Laser light source for the measurement sensor
To detect the image of the light source that appears on the workpiece
Image receiving device arranged on the optical axis of the reflected laser beam
And the spot position detected by the image receiving means.
The relative position of the laser processing head to the workpiece
And the calculated relative position data is calculated by the arithmetic means.
Calculation and output from the output means.
And a measuring and calculating device for setting the mode to a predetermined position.
In the laser processing apparatus, the reflection member is connected to the laser beam.
Workpiece by the reflection position of the beam and the laser light source for measurement
The retreat position where the image receiving means can detect the image of the light source appearing above
It is characterized in that it is configured to be able to rotate between.

According to a second aspect of the present invention, the reflecting member is provided.
Irradiates the focused laser beam to the workpiece
A mirror and a contact surface for stopping the reflecting mirror at the reflecting position
It is characterized by having. The invention according to claim 3 is
The measurement laser light source is located around the optical axis of the reflected laser beam.
At least two facing each other and a long, thin slit
It is characterized in that it is configured to form a gimbal image on the workpiece
And

[0016]

[Function] Before starting laser processing, the reflection member is measured.
Image of light source appearing on workpiece by laser light source
After the unit is rotated to the retracted position may be detected when the laser beam for meter measuring the laser <br/> The light source for measuring total irradiated toward the workpiece, the laser beam for measuring a total on the workpiece A spot appears.
The spot position is detected by the image receiving means, and the detected spot position data is input to the calculating means, which calculates the relative position of the laser processing head with respect to the workpiece. The output means sets the laser processing head at a predetermined position based on the calculated relative position data. And reflection
After moving the member to the laser beam reflection position,
Is irradiated with a laser beam to perform processing.

[0017]

An embodiment of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is an overall perspective view showing a welding robot incorporating a laser processing head according to a first embodiment of the present invention, FIG. 2 is a front sectional view showing the laser processing head, and FIG. FIG. 4 is a view showing a main body of the head, FIG. 4 is a view showing a nozzle portion to which a laser beam is irradiated, and FIGS.

In FIG. 1, a welding robot 11 has a movable robot arm 13 whose operation position is controlled by a robot controller 15, and the tip of the robot arm 13 has a laser processing head 1 according to the present embodiment.
7A is mounted, and a laser oscillator 19 is connected to the laser processing head 17A via a laser fiber 21.

As shown in FIG. 2, the laser processing head 17A has a cylindrical main body 2 to which a laser fiber 21 is connected at a base end, and a laser beam B (oscillated from a laser oscillator 19). indicated by the two-dot chain line) is he guide by the laser fiber 21.

In this embodiment, a YAG laser is used as a welding laser. However, the type of laser is not limited to this. For example, a neodymium glass laser may be used. A carbon dioxide laser or the like may be used.

A focusing lens 3 for focusing the laser beam B is attached to the tip of the main body 2, and a reflecting mirror 4 is mounted on a bracket 23 via a spring 25 on an optical axis T 1 of the focusing lens 3. Installed. A lower end of the bracket 23 is swingably supported by the main body 2, and a distal end of a wire 27 extending along the main body 2 is attached to the other end. By moving the operation knob 29 attached to the base end of the wire 27 back and forth along the longitudinal direction, the reflecting mirror 4 can move the laser reflection position shown by a solid line in FIG. Position.

As shown in FIG. 3 (a), the main body 2 is provided on both sides with mirror contact surfaces 30 that come into contact when the reflecting mirror 4 is moved to the laser reflection position. Even if there is a shift in the stop position, if the reflecting surface of the reflecting mirror 4 abuts against the mirror contact surface 30, the reflecting mirror 4 will surely be at an angle of 45 ° to the optical axis of the collecting lens 3, The laser beam B having passed through the laser beam 3 is directed downward at right angles to the optical axis T1 of the condenser lens 3. As shown in FIG. 2, a biasing force of a spring 31 may be applied to the wire 27 so that the reflecting mirror 4 moved to the laser reflection position is securely brought into close contact with the mirror contact surface 30.

The laser processing head 17A is provided with a nozzle 6 below the reflecting mirror 4. The nozzle portion 6 is a simple cylinder, and the reflected laser beam B2 reflected by the reflecting mirror 4 passes through and is radiated to the outside. The focal point F of the laser beam B is formed at a position away from the nozzle unit 6 by a predetermined distance.

As shown in FIG. 4, laser light sources 33 to 36 for measuring sensors for irradiating He-Ne laser to four equally-divided positions are attached to the edge of the nozzle portion 6, as shown in FIG. As shown in FIG. 5A, the laser beams L emitted from the laser light sources 33 to 36 for the measurement sensors all intersect at one point on the optical axis T2 of the reflected laser beam B2. . When the laser light L emitted from the laser light sources 33 to 36 for the respective measurement sensors is projected on a horizontal plane, as shown in FIG. 5B, the processing surface M of the work W is reflected by the reflected laser beam B2. When orthogonal to the axis T2, a square is formed by connecting the spot positions P1 to P4 of the laser light L for the measurement sensor irradiated on the processing surface M.

When the distance D between the diagonal lines of the square formed by the spot positions P1 to P4 is measured, H
= E (1 + D / R), the distance H from the nozzle portion to the processing surface M can be obtained. Here, E: the distance from the end face of the nozzle section 6 to the focal point F of the laser beam R: the laser light source for the measurement sensor and the nozzle section 6 facing each other
Distance between intersections with the end face of.

FIG. 6A is an explanatory view showing a laser beam irradiation state when the optical axis T2 of the reflected laser beam B2 is not orthogonal to the processing surface M, and FIG. FIG. 5 is an explanatory diagram showing a state where spot positions P1 to P4 of laser light L for a measurement sensor are projected on a plane.

As shown in FIG. 6A, even when the optical axis T2 of the reflected laser beam B2 is not orthogonal to the processing surface M,
Intersection of machining surface M and reflected laser beam B2, ie, centroid O
And the laser spot position P1 on the processing surface M
The distances (commonly called spot depths) K1 to K4 between .about.P4 and the horizontal plane (shown by broken lines) at the focal point F are determined, and these values are used to solve a so-called plane equation. The distance H to the center O and the angle between the reflected laser beam B2 and the processing surface M can be determined.

An image receiving device 41, such as a CCD camera, is attached to the upper end of the laser processing head 17A. The image receiving device 41 is mounted so that its optical axis coincides with the optical axis T2 of the reflected laser beam B2 reflected by the reflecting mirror, and when the reflecting mirror 4 is moved to the retracted position, the processing visible from the nozzle portion 6 The state of the surface M can be photographed. Therefore, when the image receiving device 41 shoots the spots P1 to P4 of the laser beams from the laser light sources 33 to 36 for the measurement sensor projected on the processing surface M of the work W, the positions of the spots P1 to P4 can be detected. . The position data of the spots P1 to P4 photographed and detected by the image receiving device 41 are transmitted to the measurement operation device 43 (FIG. 1), and arithmetic processing such as solving the above-described plane equation is performed based on these data. Will be

Next, a procedure for teaching the laser processing head of this embodiment to a predetermined teaching position will be described with reference to flowcharts shown in FIGS.

FIG. 7 is a flowchart showing the operation procedure of the worker, FIG. 8 is a flowchart showing the operation of the measurement sensor, and FIG. 9 is a flowchart showing the operation of the calculation unit. In FIG. 7, first, the operator operates the welding robot 11 to move the laser processing head 17A to a target position (S1). At this time, the reflecting mirror 4 of the laser processing head 17A is used.
Is moved to the retreat position by operating the operation knob 29,
The image receiving device 41 can take an image of the processing surface M seen from the nozzle unit 6.

Next, as shown in FIG. 8, the operation of the measurement sensor is started. The processing surface M is irradiated with He-Ne laser light for a measurement sensor from the laser light sources 33 to 36 (S
2). By this irradiation, spots P1 to P4 appear on the processing surface M of the work W as shown in FIG. The positions of these spots P1 to P4 are captured as image data by the image receiving device 41 (S3), and the positions are detected. The spot position data detected by the image receiving device 41 is transmitted to the measuring and calculating device 43 (S4), and as shown in FIG. 9, first, the intersection between the optical axis T2 of the reflected laser beam B2 and the processing surface M, that is, the centroid O Is obtained (S5).
Next, the distances between the laser spot positions P1 to P4 and the horizontal plane at the focal point F (commonly called spot depths) K1 to K
4 is obtained (S6). Then, based on these values, a so-called plane equation is calculated (S7), and a distance H (a so-called Z-axis distance) from the end face of the nozzle portion 6 to the centroid O, a so-called X-axis and a Y-axis The relative position or angle between the nozzle portion 6 and the processing surface M is obtained from the inclination angle of the nozzle (S8). These values are displayed on the display device 45 (S9), and it is determined whether or not each value is within an allowable range as shown in FIG. 7 (S10).

If each value deviates from the allowable range, the position and angle of the laser processing head 17A are corrected according to the deviation (S11). After this correction, the positions of the spots P1 to P4 by the laser light L for the measurement sensor are measured again, and the relative positions of the laser processing head 17A with respect to the processing surface M are obtained (S2 to S9). It is determined whether or not there is (S10).

If each value is within the allowable range, the position is taught by the laser processing head 17A, and if there is a next taught position, the operation proceeds to the next teaching operation. If there is no point to teach, the teaching operation ends. When the teaching operation is completed, the operation knob 29 is operated to move the reflecting mirror 4 to the laser reflection position and fix it.

As described above, in the above-described embodiment, the positions of the spots P1 to P4 by the laser light L for the measurement sensor irradiated on the processing surface M are detected by the image receiving device 41, and the position of the laser processing head 17A relative to the processing surface M is detected. The relative position or angle is obtained, and if these values are within the allowable range, the laser processing head 17A is taught a predetermined position, so that the position of the laser processing head 17A with respect to the processing surface can be automatically detected and measured. The position teaching operation for the processing head 17A is accurate, simple and quick, and the burden on the operator is reduced. In particular, trial welding can be minimized (none in this embodiment), and the time required for teaching the robot position can be greatly reduced. In addition, the work for trial welding becomes unnecessary, and the amount of material is reduced.

[0035]

[0036]

[0037]

[0038] Using the cross-sectional view of a laser machining head, Figure 1 1 is an explanatory view showing a measurement state of the embodiment, FIG. 1 2 butt welding of the second embodiment of the second embodiment Figure 1 0 is the invention perspective view showing a state, FIG. 1 3 is an explanatory diagram showing a relationship between the focal position of the slit light and the laser irradiated to the workpiece to be butt welded. Laser processing head 17C of the embodiment shown in FIG. 1 0, since the configuration of the majority is the same as the first embodiment shown in FIG. 2,
The same reference numerals are given and the description is omitted, but the difference is that a semi-cylindrical lens 60 is attached to the tip of the laser light source 33 or 35 for the measurement sensor. That is, unlike the four laser light sources of the first embodiment, the number of laser light sources 33 and 35 for the measurement sensor may be two, and the lens 60 in a semicylindrical shape is attached to the tip.

By doing so, the laser light sources 33, 35
The laser light L emitted from the laser beam is turned into a slit-like elongated light by the lens 60 having a semi-cylindrical shape,
Thus, linear spots P1 and P2 are formed.
When the slit light is detected by the image receiving device 41 and the relative position or angle of the laser processing head 17C with respect to the processing surface M is obtained, a predetermined position can be taught to the laser processing head.

[0040] For example, in the case of a) solid state shown in FIG. 1 1, the spot P1 and the spot P2 becomes a parallel state,
The distance d between the two spots P1 and P2 is a predetermined d0, and the relative distance H between the processing surface M and the laser processing head 17C is a predetermined H0.

B) When the relative distance H is shorter than a predetermined value H0, the two spots P1 and P2 are in a parallel state, and the distance d between the two spots P1 and P2 is smaller than a predetermined value d0. c) When the relative distance H is longer than a predetermined value H0, both spots P1 and P2 are in a parallel state, and both spots P1 and P2 are parallel.
, P2 is greater than a predetermined value d0. The relative distance H in the cases b) and c) can be obtained by H = H0 + ＝ (d−d0).

[0042] d) As shown in FIG. 1 1 by a two-dot chain line, when rotated about an axis perpendicular to the plane by an angle θ with the processing surface M is two spots P1, P2 becomes a parallel state, light The position of the axis T2 and the spot P1 or the spot P2 are d1 and d2 different from each other. In this case, the rotation angle θ can be obtained from θ = sin ⁻¹ {(d1−d2) / (d1 + d2)}.

E) When the processing surface M is rotated by an angle φ about an axis orthogonal to the optical axis T2, the distance d between the spots P1 and P2 is different at both ends. If the distance at one end is d1 and the distance at the other end is d2, the rotation angle φ
Can be obtained from φ = sin ^-1 {(d1 -d2) / l}. Here, "l" is the length of the slit light, that is, the length when both spots P1 and P2 are projected on a horizontal plane.

In the second embodiment, the laser light from the laser light sources 33 and 35 for the two measurement sensors is converted into slit light by the lens 60 having a semi-cylindrical shape. Thus, even if the processing surface M of the workpiece W is in any state such as perspective, inclined, or rotating, the relative distance and angle can be detected as described above, and as in the above-described embodiment, Accurate and quick teaching work can be easily performed, and the burden on the worker performing the teaching work is reduced.

[0045] Accordingly, various ones are subject regarding the state of the workpiece, as shown in FIG. 1 2, also used to close disposed ends of a pair of workpieces, performed both butt welding can do. In this case, the laser light L radiated from the laser light sources 33 and 35 for the two measurement sensors via the lens 60 in a semi-cylindrical shape,
In part of the groove position 62 between the butt end of FIG. 1 2,
As shown in 1 3, it becomes partially deformed. The position of the deformed portion 63 of the slit light in the entire slit light makes it possible to determine whether or not the position coincides with the focal position of the reflected laser light B. Based on this, the teaching position of the robot can be corrected. .

In the case of lap welding or the like without the groove position 62, the welding can be performed by making a mark on the portion to be welded so as to be readable by the slit light.

Further, the laser light for processing is directly focused on the workpiece W and run, and a bead generated on the workpiece W, a burn pattern drawn when the workpiece W is an acrylic plate, and the like are formed. By measuring the position using the slit light from the laser light sources 33 and 35 for the two measurement sensors described above, the focal position of the reflected laser light B can be detected and the teaching position of the robot can be corrected. is there.

[0048]

[0049]

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the claims. For example, in the above embodiment, a CCD camera is used as the image receiving means. However, not only this, but other appropriate means may be used. Further, the laser light source for the measurement sensor is not limited to an even number of 2 or 4, but may be 1 or more.

[0051]

As described above, according to the present invention, the reflection member
Shows the reflection position of the laser beam and the image of the measurement laser light source.
So that it can rotate between a retracted position that the image receiving means can detect.
Before performing laser processing, the reflective member must be
When the retracted position is set, the workpiece is
Laser processing head position easily and quickly
When performing laser processing, turn the reflective member to
The workpiece can be machined at an appropriate reflection position. Ma
In addition, the reflector is turned to abut against the contact surface at the reflection position and stopped.
With this configuration, simply turning the reflecting member can
It can be set to a precise reflection position and accurately receives the reflected laser beam.
Can be directed to the workpiece. In addition, laser light for measurement
Is the slit light, the laser spot on the processing surface
The laser beam oscillated from the laser oscillation source.
The light guide path is displaced by the optical fiber or reflector that guides the
But also for defocus caused by deflection
Corresponds to variations in groove position such as counter welding
To correct the teaching position of the robot.

Furthermore, if the laser light for the measurement sensor is slit light, the laser spot on the processing surface becomes linear, so that an optical fiber for guiding the laser beam oscillated from the laser oscillation source or a light guide path by a reflecting mirror is used. The teaching position of the robot can be corrected correspondingly to the defocus caused by the deviation or deflection, and also to the variation of the groove position such as butt welding.

[Brief description of the drawings]

FIG. 1 is an external view showing a laser processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a front sectional view showing the laser processing head of the first embodiment.

3 is a drawing showing a main body, FIG. 3 (a) is a front view, and FIG. 3 (b) is a side view.

4 is a view in the direction of arrow A1 in FIG. 2 showing a nozzle portion.

5A and 5B are views showing a nozzle portion, FIG. 5A is an enlarged front view, and FIG. 5B is an arrow A2 showing a work surface of a workpiece.
It is an arrow view of a direction.

6A and 6B are views showing a nozzle portion, FIG. 6A is an enlarged front view, and FIG. 6B is an arrow A3 showing a work surface of a workpiece.
It is an arrow view of a direction.

FIG. 7 is a flowchart showing the work of the worker.

FIG. 8 is a flowchart showing the operation of the measurement sensor.

FIG. 9 is a flowchart illustrating the operation of the arithmetic processing unit.

FIG. 10 shows a laser processing head according to a second embodiment of the present invention .
It is a front cross-sectional view illustrating.

FIG. 11 shows a state during a teaching operation of the second embodiment .
It is an explanatory diagram.

FIG. 12 shows a state during a teaching operation of a modification of the second embodiment .
It is a perspective view showing a state .

FIG. 13 is an explanatory diagram showing a state of slit light in the modification .

FIG. 14 is a front sectional view showing an example of a conventional laser processing head.

FIG. 15 is a side view showing an adjustment jig conventionally used.

FIG. 16 is a schematic view showing another example of a conventional laser processing head.

FIG. 17 is a schematic diagram showing a confirmation state of an optical path in another example.

[Explanation of symbols]

3 condensing lens, 4 reflecting mirror, 6 nozzle section, 17A
Laser processing head, 19: Laser oscillator 30: Mirror
Surface 33-36 laser light source 41 image receiving device 43
... Measurement calculation device, B ... Laser beam for processing, F ... Focus, L
... Laser light for measurement, M. Work surface, P1 to P4. Spot, T1, T2. Optical axis, W. Workpiece.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-72692 (JP, A) JP-A-61-2802 (JP, A) JP-A-63-16892 (JP, A) JP-A 64-64 15295 (JP, A) JP-A-4-55078 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 26/00-26/42

Claims (3)

(57) [Claims] A laser processing head configured to reflect a laser beam radiated from an output source and condensed by a condensing means by a reflecting member, and to irradiate the workpiece with the reflected laser beam; Are arranged around the optical axis of
A laser light source for a measurement sensor configured to irradiate a measurement laser beam obliquely toward the workpiece so as to intersect at an upper portion of the workpiece, and a light source that appears on the workpiece with the measurement laser light. Image receiving means arranged on the optical axis of the reflected laser beam so as to detect the image of, the relative position of the laser processing head with respect to the workpiece based on the spot position detected by the image receiving means,
The obtained relative position data is calculated by a calculating means, and a measuring and calculating device for setting the laser processing head to a predetermined position by an output from an output means. A laser processing apparatus characterized in that it can rotate between a beam reflection position and a retreat position where an image receiving unit can detect an image of a light source appearing on a workpiece by the measurement laser light source. 2. The reflection member according to claim 1, wherein the reflection member includes a reflection mirror for irradiating the converged laser beam to the workpiece, and a contact surface for stopping the reflection mirror at the reflection position. The laser processing apparatus according to item 1. 3. The measuring laser light source is disposed so as to face at least two around the optical axis of the reflected laser beam,
The laser processing apparatus according to claim 1, wherein a long and narrow slit-shaped image is formed on the workpiece.