JPH11156578A - Laser processing device and focusing position deciding method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a teaching time by using a laser pointer instead of a processing laser light so as to easily focus a focal position of a processing point indicating laser light being output from the laser pointer on a given processing point on a workpiece. SOLUTION: When an operator pushes a vibration key on a teaching box at the time ts, a tool center point (focusing position, focal position) TCP of a working point indicating laser light Lp on a workpiece W is automatically moved in a front/rear direction at a constant amplitude. The operator can immediately grasp the changing tendency of the size of a luminance simply by monitoring the luminance on the workpiece W. As a result of pushing the vibration key again, for example, at the time te when the size of the luminance becomes minimum, the tool center point TCP can be focused on a processing point J on the workpiece W. Thus, the tool center point TCP can be simply and accurately specified at the processing point J in a short time.

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 introducing a laser beam emitted from a laser oscillator into a processing head and scanning a workpiece with the laser beam to perform processing, and a focusing position in the laser processing apparatus. Regarding the decision method.

[0002]

2. Description of the Related Art Conventionally, there has been known a laser processing method in which a workpiece is irradiated with a laser beam, and the workpiece is heated and evaporated or melted to perform processing such as cutting or welding. The laser processing apparatus used at this time introduces the laser beam emitted from the laser oscillator to the processing head, and focussed optical means provided on the processing head,
The laser beam is focused on a desired position of the workpiece via a scanning optical unit.

[0003]

For example, when the above-mentioned laser processing apparatus is used as a welding robot in an automobile manufacturing line, the workpiece to be welded to the welding robot before the actual welding operation is performed. A so-called teaching operation (teaching operation) is required in which a movement path of the laser beam irradiation point on the (workpiece) is taught and stored in a computer (controller).

At the time of this teaching operation, a low-output visible light such as a semiconductor laser is used instead of a high-output laser light (a processing laser light) such as a CO ₂ laser used in actual processing. It is conceivable to use laser light (referred to as a processing point indicating laser light).

[0005] In order to improve the quality of laser welding, it is desirable that the laser beam converge, that is, be focused on the processing point on the workpiece. For this reason, during the teaching operation, when the desired processing point on the workpiece is irradiated with the processing point indicating laser light, the blur (the size of the bright point) of the luminescent point of the processing point indicating laser light is reduced. It is necessary to adjust the focusing optics to a minimum.

When the size of the luminescent spot of the processing point indicating laser beam is minimized on the workpiece, the adjustment amount of the focusing optical means and the adjustment amount of the scanning optical means are equal to the desired processing point. Is used as teaching data for processing

However, in practice, as schematically shown in FIG. 11, for example, at a certain processing point J1 on the workpiece W, the brightness of the processing point designating laser light Lp irradiated through the scanning mirror 1 is increased. From the position where the size of the point Bs is minimized and focused (see FIG. 11A), when the operator operates the scanning mirror 1 to specify the next processing point J2 on the workpiece W, Defocus at the processing point J2 of
The size of s increases (see FIG. 11B). At this time,
The operator operates a focusing optical unit (not shown) to focus the laser beam Lp for processing point indication (focus position).
Needs to be moved forward or backward in the irradiation direction at the processing point J2 to adjust so that the size of the bright spot Bs is minimized, that is, so-called just focus (see FIG. 11C).

That is, as shown in the upper side view of FIG. 12B, when the focal point is nearer to the processing point J2,
As shown in the upper side view of FIG. 12C, when the focal point is behind (backward) with respect to the processing point J2, the focusing position (focal position) is shifted. Therefore, as shown in the lower plan views of FIGS. 12B and 12C, at the processing point J2, the bright spot Bs
Becomes large. Therefore, in the case of FIG. 12B,
Adjusting the focusing optical means to the rear (back) direction of the workpiece W
12C, and in the case of FIG. 12C, the focal position is moved in the forward direction. As shown in the upper side view of FIG. 12A and the lower plan view of FIG. It is necessary to adjust the size of the point Bs so as to be minimum (just focus).

However, during this focus adjustment operation,
The operator is confused as to which one of the forward and backward irradiation directions to operate the focusing optical means, and as a result, the operation of focusing at the new processing point J2, in other words, In this case, there is a problem that the teaching operation takes a long time.

[0010] Further, there is a problem that the operation of adjusting the size of the bright spot at the new processing point J2 to be minimum requires skill.

The present invention has been made in consideration of such problems, and simplifies the operation of adjusting the focus position (focal position) of a processing point indicating laser beam, and adjusts the focus position on a workpiece. It is an object of the present invention to provide a laser processing apparatus and a focusing position determination method in the laser processing apparatus, which can shorten the adjustment time.

[0012]

According to the present invention, a processing laser beam output from a laser oscillator is focused at a desired position on a workpiece through focusing optical means and scanning optical means, and the focusing position is determined. In the laser processing apparatus performing the processing in the above, the processing laser light is arranged on the optical axis of the processing laser light in place of the processing laser light, and is a visible laser light that indicates a processing point of the workpiece. A processing point indicating laser light oscillator that outputs laser light, and a focusing position of the processing point indicating laser light on the workpiece adjusted by the focusing optical unit, the front-back direction of the irradiation direction of the workpiece. And a focusing position automatic moving means for automatically moving at a constant amplitude.

According to the present invention, there is provided a focus position automatic moving means for automatically moving the focus position of the processing point indicating laser beam on the workpiece with a constant amplitude in the front-rear direction of the irradiation direction of the workpiece. Eliminates the need for the operator to operate the focusing optics to find the focusing position,
The focusing position can be determined on the workpiece in a short time and easily. The work for determining the focusing position on the workpiece requires almost no skill.

In this case, the image pickup means picks up an image of the luminescent spot of the processing point indicating laser beam on the workpiece, operates the automatic focusing position moving means, and converts the processing point from the image signal picked up by the image pickup means. When the focus position at which the size of the luminescent spot of the instruction laser light is minimized is detected, the operation of the focus position automatic moving means is stopped, so that the focus position can be automatically, quickly and easily set on the workpiece. Can be matched.

Further, according to the present invention, the processing laser light output from the laser oscillator is focused at a desired position on the workpiece via the focusing optical means and the scanning optical means, and processing is performed at the focusing position. In the focusing position determination method in the laser processing apparatus, on the optical axis of the processing laser light,
A processing point indicating laser light oscillator that outputs a processing point indicating laser light that is a visible laser light that indicates a processing point instead of the processing laser light is arranged to align the optical axis, and the processing point indicating laser is provided. The irradiation position of the light is temporarily adjusted to a position to be processed on the workpiece by operating the scanning optical unit, and the focusing optical unit is moved with the focusing position in the front-back direction of the irradiation direction with reference to the provisional position. The apparatus is characterized in that the laser beam is automatically moved so as to determine the convergence position of the processing point indicating laser light.

According to the present invention, the irradiation position of the processing point indicating laser light is temporarily adjusted to the position to be processed on the workpiece by operating the scanning optical means, and the focusing optics is determined based on the provisional position. The focusing means is operated so that the focusing position automatically moves in the front-back direction of the irradiation direction to determine the focusing position of the processing point indicating laser light. Can be fitted on the workpiece.

[0017]

An embodiment of the present invention will be described below with reference to the drawings. In the drawings referred to below, the same reference numerals are given to those corresponding to those shown in FIGS. 11 and 12 described above.

FIG. 1 shows a schematic configuration of a production line 10 to which an embodiment of the present invention is applied.

This production line 10 basically includes a production line 10 including a transport control of a workpiece W such as an automobile.
A master controller 14 which is an overall control device of
A robot controller 16 also serving as a laser controller (laser controller) started by the master controller 14; a welding robot 18 whose operation is controlled by the robot controller 16;
0 is mounted on the laser control panel 20.

The robot controller 16 has a CPU 22 which is a central processing unit having an arithmetic control function. A ROM (read only memory) 25 in which a control program is stored via a bus 24 for the CPU 22 A RAM (random access memory) 26 as a storage means to be used is connected, a timer 27 as a time measuring means is connected, and a hard disk as a large-capacity storage device for storing teaching data, a focusing position automatic moving program and the like. Device 28 is interface 3
0.

The bus 24 also has an interface 3
A master controller 14, a welding robot 18, and a teaching box 38 for performing a teaching operation and the like are connected to each other via communication lines 2, 34, 36 and communication lines. The teaching box 38 includes a display 38A for displaying teaching data and the like, a numeric keypad 38B including a return key and sign (+,-) keys, and a function key 38.
C, irradiation position and focus position of laser beam L (focus position)
And a vibration key 38E functioning as a focus position movement operation start means and a focus position movement operation stop means for operating and stopping a focusing position automatic movement means described later.

Further, the bus 24 has an interface 4
In order to switch the operation mode of the welding robot 18 via 0, an operation mode changeover switch 42, which is a quadruple push button switch capable of selecting and pressing (turning on) only one arbitrary push button. Is connected. The operation mode changeover switch 42 is attached to a panel surface of the robot controller 16.

The operation modes that can be switched include an OFF operation (non-operation) mode in which the welding robot 18 is in a non-operation state, and teaching data in accordance with the ON state of the operation mode changeover switches 42A, 42B, 42C, and 42D. Teaching operation style for obtaining (teaching data),
It is possible to select a teaching operation confirmation mode for judging the suitability of the obtained teaching data, and a welding operation mode for actually welding the workpiece W with the laser beam L based on the confirmed teaching data.

The processing head 52 attached to the tip of an arm (not shown) of the welding robot 18 has a scanning optical system 56 and an optical system driving motor 58 for driving the scanning optical system 56.

The scanning optical system 56 includes an optical system driving motor 58
, A high-output laser beam (processing laser beam, and in this embodiment, a welding laser beam in this embodiment) L1 output from a laser oscillator 50 having a CO ₂ laser oscillation tube and introduced through a laser shutter 54. Alternatively, the workpiece W is scanned with the processing point indicating laser light Lp, which is a low-output visible laser light introduced from a laser pointer (a processing point indicating laser light oscillator) 62 having a semiconductor laser.
In this case, at the same time as the scanning, the laser beams L1 and Lp (the reference numeral is L when there is no need to distinguish between them) are the tool center point TCP which is the focal position (focal position) of the laser beam L. Is adjusted by the focusing optical means in the processing head 52 so as to coincide with the processing point of the workpiece W.

The scanning of the laser beam L by the processing head 52 and the adjustment of the focusing position (focal position) are performed by an optical system driving motor 58 and a scanning optical system 5 through an interface 60 connected to the bus 24 of the robot controller 16 as described later.
6 is performed.

A laser pointer 62 for emitting the processing point indicating laser light Lp is attached to the rod 66. The expansion and contraction of the rod 66 in the direction of the arrow D or the direction of the arrow U is performed by a servo motor (not shown) included in the pointer control circuit 64 attached to the welding robot 18 through the interface 68 connected to the bus 24 of the robot controller 16. It is controlled by being controlled through. When the rod 66 is extended in the direction of arrow D, the rod is preliminarily set so that the optical axis of the processing point indicating laser light Lp output from the laser pointer 62 is coaxial with the optical axis of the high-power laser light L1 for processing. The amount of elongation of 66 is adjusted.

The laser pointer 62 has its light emission mode (irradiation mode when considered on the workpiece W) controlled by the robot controller 16 through the interface 68 through the pointer control circuit 64.

In this embodiment, the light emission mode (irradiation mode) of the laser pointer 62 is a constant output laser beam L.
p: continuous emission (continuous irradiation) mode and non-emission (non-irradiation) mode. In this case, the operation mode changeover switch 42
In the off operation mode in which A is turned on or the welding operation mode in which operation mode changeover switch 42D is turned on, non-light emission mode is set. In the teaching operation mode in which the operation mode switch 42B is turned on, the continuous light mode is used. Further, at the time of confirming the teaching operation in which the operation mode changeover switch 42C is turned on, the mixed irradiation mode in which the processed portion is continuously irradiated and the non-processed portion is not irradiated is set. The laser shutter 54 is arranged on the laser control panel 20 including the laser power supply connected via the interface 79 of the robot controller 16. This laser shutter 54
The operation is controlled through the interface 70 and the shutter control circuit 72 of the robot controller 16. When shutting off the laser beam L1, the laser shutter 54
Under the action of the shutter control circuit 72, a total reflection mirror (not shown) inclined by 45 ° with respect to the optical axis of the laser light L1 is inserted so as to block the optical path, and the laser light reflected by the total reflection mirror L1 is controlled so as to irradiate a laser light absorbing mechanism (not shown). The laser light absorption mechanism includes a heat conversion mechanism (not shown) that converts the irradiated laser light L1 into heat, and a cooling mechanism (not shown) that cools the heat conversion mechanism.

FIG. 2 shows the scanning optical system 5 in the processing head 52.
6 shows a schematic perspective configuration of FIG. FIG. 3 shows a schematic configuration of the processing head 52 viewed from the side.

In FIG. 2, the scanning optical system 56 includes an optical surface plate 120, on which the parabolic mirror 1 is mounted.
22 is fixed. As shown in FIG. 3, the laser beam L introduced into the processing head 52 is
After being reflected once, the light is once focused, then spread, and simultaneously moved in the arrow P direction or the arrow Q direction by the focus adjustment motor 103, and is sequentially reflected by the focus adjustment mirrors 124 and 126, which are plane mirrors, respectively. After the optical path is changed, the light is introduced into the elliptical mirror 128.

The laser beam L introduced into the elliptical mirror 128 is reflected by the elliptical mirror 128, starts to converge again, and is turned by the X-axis motor 101 about the X-axis 129 in the direction of the arrow. After being reflected by an X-axis scanning mirror 131 which is a mirror, the Y-axis motor 102
The optical surface plate 1 is reflected by a Y-axis scanning mirror 132 which is a plane mirror which is turned around a shaft 130 in an arrow direction.
The light is emitted from the processing head 52 through the opening 134 of the workpiece 20 and is focused at the processing point J on the workpiece W. In this case, the positions of the focus adjustment mirrors 124 and 126 are adjusted by the focus adjustment motor 103 so that the processing point J becomes the tool center point TCP which is the focus of the laser beam L.

In the processing head 52 of this embodiment, the focal length adjustment range from the Y-axis scanning mirror 132 to the tool center point TCP is about 50 cm to 130 cm (for example, Japanese Patent Application Laid-Open No. H9-1998 filed by the present applicant). -1928
No. 68).

At the position shown in FIG. 3, when the Y-axis scanning mirror 132 is rotated, the tool center point TCP
Moves in the direction substantially in the depth of the paper, and the X-axis scanning mirror 13
When 1 is rotated, the tool center point TCP moves in a substantially left-right direction substantially parallel to the paper surface. During this scan,
The positions of the focus adjusting mirrors 124 and 126 are adjusted so that the tool center point TCP which is the focal point at the desired processing point J on the processing surface of the workpiece W coincides.

In this case, as can be seen from FIG. 3, the scanning optical system 56 includes a parabolic mirror 122, focusing mirrors 124 and 126, which are plane mirrors, and an elliptical mirror 12.
Focusing optical means 56A composed of
Scanning optical means 56B comprising a scanning mirror 132 and a Y-axis scanning mirror 132
It is composed of

FIG. 4 shows an equivalent optical system circuit of the focusing optical means 56A. Here, assuming that the focal length of the parabolic mirror 122 is f and the focal length of an equivalent lens (equivalent lens) Le formed by the focus adjusting mirrors 124 and 126 and the elliptical mirror 128 is F, The laser light L incident parallel to the object plane mirror 122 is converged at a position A with a focal length f, spreads, and is converged again by the equivalent lens Le. At this time, the distance on the optical axis between the position A and the equivalent lens Le is S ₁ , and the distance on the optical axis between the equivalent lens Le and the tool center point TCP which is an optical focusing position (focal position) is When S _2, relational expressions shown in the following (1) is obtained.

1 / S ₁ + 1 / S ₂ = 1 / F (1) For this reason, the equivalent lens Le and the tool center point TC on the optical axis
If it is the distance S ₂ is larger settings is P, only the distance S ₁ is being slightly changed, the distance S ₂ (TCP tool center point is the focal position) is to be changed greatly.

FIG. 5 is a block diagram showing an electrical configuration for a scanning / focus adjustment mechanism for scanning the laser beam L and adjusting the focus. The interface 60 connected to the bus 24 of the robot controller 16 includes D / A converters 81 to 83, servo amplifiers X-axis amplifier 91 and Y-axis amplifier 92 connected to the output side, respectively, An amplifier 93 is included. Outputs of the amplifiers 91 to 93 are supplied to an X-axis motor 101, a Y-axis motor 102, and a focus adjustment motor 103, which are servo motors constituting the optical system drive motor 58, respectively. Motor 101
The operations of the X-axis scanning mirror 131, the Y-axis scanning mirror 132, and the focus adjustment mirrors 124 and 126, which constitute the scanning optical system 56, are controlled by to 103.

Next, the operation of the above embodiment will be described.
This will be described in detail based on the flowchart shown in FIG. In addition,
Unless otherwise specified, the control entity is the CPU 22, but since it is complicated to refer to this each time, it is referred to as necessary.

When the teaching operation mode changeover switch 42b on the panel surface of the robot controller 16 is turned on by the operator in the off state of the laser oscillator 50, the CPU 22 recognizes that the teaching operation mode has been selected. Step S1).

When it is recognized that the teaching operation mode has been selected, the laser pointer 62 is turned on in the continuous emission mode via the interface 68 and the pointer control circuit 64 (step S2).

Further, the rod 66 is extended in the direction of arrow D, and the laser pointer 62 is arranged on the optical path (optical axis) (step S3). As a result, the workpiece W is irradiated with the processing point indicating laser light Lp, which is a low-output visible laser light.

In this state, the operator operates the teaching box 38 to operate the scanning optical means 56B to move the luminescent spot Bs, so that the luminescent spot Bs is moved.
In other words, the irradiation position of the processing point instruction laser beam Lp is temporarily adjusted to the position (processing point) J on the workpiece W to be processed (step S4).

In this tentative position, generally, the tool center point TC which is the focus position of the processing point indicating laser light Lp
P does not coincide with the position of the processing point J on the workpiece W in a direction intersecting the processing surface of the workpiece W.

The operator presses the vibration key 3 to adjust the focus position (focus position) of the scanning optical system 56.
8E is pressed once for operation (step S5). As a result, the vibration key 38E is turned on, the focusing position automatic movement program shown in FIG. 7 is started by the CPU 22, and the execution of this program is started.

At this time, when the robot controller 16 is started, a vibration pattern, which will be described later, stored in the RAM 26 from the hard disk drive 28 when the robot controller 16 is started is read from the RAM 26 (step S61) and set in the focus adjustment amplifier 93 through the D / A converter 83. Is performed (step S62).

FIG. 8 shows a vibration pattern VT set in the focus adjustment amplifier 93. In FIG. 8, the horizontal axis is the time axis, and the vertical axis is the amplitude.

As can be seen from FIG. 8, the vibration pattern VT
Is a pattern in which a vibration cycle (moving cycle, moving speed) T1 and a vibration amplitude V1 are defined in a triangular wave as parameters. In this embodiment, the vibration pattern VT
Are set as default values, the vibration cycle T1 is set to T1 = 2s, and the vibration amplitude V1 is set to V1 = ± 30 m
m. Note that the vibration period T1 and the vibration amplitude V
By operating the teaching box 38, the parameter of the vibration pattern VT consisting of 1 can be changed to a desired pattern that meets the sensitivity of the operator.

When the focus adjustment motor 103 is rotated forward and backward in accordance with the vibration pattern VT, the focus adjustment mirror 124 (126) is automatically moved in the arrow Q direction or the P direction (see FIGS. 2 and 4). (Step S
63). In this embodiment, the focusing position automatic moving means operates according to the focusing position automatic vibration program.
Focus adjusting mirror 124 whose position is controlled by the
(126) corresponds to this.

At this time, the tool center point TCP is automatically moved on the processing point J of the workpiece W in the front-rear direction, that is, the irradiation direction of the processing point indicating laser beam Lp, in other words, on the optical axis. 12B, FIG. 12C, and FIG.
Since the change of the magnitude of s is repeated, the operator re-oscillates at the position where the size of the bright spot Bs becomes the minimum (just focus) at the processing point J2 (for example, the symbol J in FIG. 2). Press the key 38E (step S6).
4) Stop automatic movement (step S65).

FIG. 9 schematically shows the locus of the tool center point TCP of the processing point indicating laser light Lp from the first press of the vibration key 38E to the press of the vibration key 38E, that is, the trajectory of the focus position (focal position). ing. The position of the tool center point TCP at the time point ts on the horizontal axis in FIG. 9 is the provisional position. In this example of FIG. 9, the provisional focal position is on the far side of the workpiece W. In the example of FIG. 9, when the tool center point TCP coincides with the machining point J on the workpiece W at the time point te after the automatic oscillation for about three cycles of the oscillation cycle T1 described above, again. When the vibration key 38E is pressed, the tool center point TCP of the processing point indicating laser light Lp,
That is, it is understood that the focus position coincides with the workpiece W.

As described above, the operator operates the vibration key 38E.
By simply pressing, the laser light L for indicating the processing point on the workpiece W
The tool center point TCP of p is the laser beam Lp of the workpiece W
Is automatically moved at a constant amplitude in the front-rear direction of the irradiation direction, so that the operator merely observes the bright spot Bs on the workpiece W, and the operator tends to change the size of the bright spot Bs. Can be immediately captured, and when the size of the bright spot Bs is minimized, the vibration key 38E is pressed again. As a result, the tool center point TCP is accurately positioned at the processing point J on the workpiece W. Can be matched. For this reason,
The tool center point TCP can be easily and accurately adjusted to the machining point J in a short time.

Thereafter, by operating the teaching box 38, the stop position of the bright spot Bs is stored as the teaching point (teaching data) of the processing point J (step S7).

At this time, by inputting the operation code (welding speed, moving speed, etc.) related to the teaching point J, the machining point J
Is completed and stored in the hard disk drive 28 (step S8).

Thereafter, the operation mode changeover switch 42C is turned on, the teaching operation confirmation mode is selected, and the propriety of the teaching data created in the teaching operation mode up to step S8 is confirmed. Then, when the confirmation and correction of the teaching data are completed, the operation mode changeover switch 42A is turned on to turn it off.

Next, when actual welding is performed, when the welding operation mode changeover switch 42D is turned on by the operator, whether or not the laser pointer 62 is on the optical axis is confirmed. If you do
It is retracted from the position on the optical axis to the original position. Next, the laser oscillator 50 is turned on while the laser shutter 54 is closed and the processing laser light L1 is not output. Thereafter, a start signal is supplied from the master controller 14 to the robot controller 16 so that a welding operation on the workpiece W based on the above-described teaching data is performed.

In the above-described embodiment, the operator observes the luminescent spot Bs and sets the processing point designating laser light Lp.
Although the position where it is determined that the tool center point TCP, which is the convergence position of the tool, coincides with the workpiece W is taught as teaching data, the present invention is not limited to this, and as shown in FIG. A video camera 76 as an imaging means is integrally attached via an imaging processing circuit 74,
The video camera 76 can also be configured to be controlled via the interface 35 and the imaging processing circuit 74.

In the example of FIG. 10, during the execution of the automatic focusing position moving program in step S6 in FIG. 6, the video camera 76 captures an image of the luminescent spot Bs of the processing point indicating laser light Lp on the workpiece W, When detecting the focus position where the size of the luminescent spot Bs of the processing point indicating laser beam Lp is minimum from the image pickup signal output from the video camera 76, the apparatus automatically responds to the operation of turning off the vibration key 38E (step S64). Is performed. Thereby, the tool center point T
The optimal position of the focusing mirrors 124 and 126 in the focusing optical means 56A for setting the CP to the processing point J on the workpiece W, that is, the teaching data as the drive value of the focusing motor 103 is automatically calculated. Can be determined.

The present invention is not limited to the above-described embodiment, but can adopt various configurations without departing from the gist of the present invention.

[0060]

As described above, according to the present invention, the focusing position of the laser beam for indicating the processing point on the workpiece is
Since the focusing position automatic moving means for automatically moving the workpiece in the front-back direction with a constant amplitude in the irradiation direction is provided, the operator does not need to manually operate the focusing optical means to find the focusing position. In addition, the focusing position can be determined to be a processing point on a workpiece in a short time, accurately, and without skill.

As a result, the teaching data of the focusing optical means can be accurately determined in a short time.

In this case, the image pick-up means picks up an image of the luminescent spot of the processing point indicating laser beam on the workpiece, activates the automatic focusing position moving means, and operates the processing point from the image signal picked up by the image pick-up means. When the focus position at which the size of the luminescent spot of the instruction laser beam is minimized is detected, the operation of the automatic focus position moving means is stopped, so that the focus position can be automatically made coincident with the workpiece.

According to the present invention, the irradiation position of the processing point indicating laser light is temporarily adjusted to the position to be processed on the workpiece by operating the scanning optical means, and the focusing optics is determined based on the provisional position. The means is operated so that the focus position automatically moves in the front-back direction of the irradiation direction, so that the focus position of the processing point indicating laser light coincides with the work piece. The focusing position can be accurately determined in a short time.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a production line to which an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing a schematic configuration of a scanning optical system in the processing head.

FIG. 3 is a partial side sectional view schematically showing a configuration of a processing head.

FIG. 4 is a diagram used for explaining the operation of the equivalent optical system circuit;

FIG. 5 shows scanning for adjusting a focus by scanning a laser beam.
FIG. 3 is a block diagram illustrating an electrical configuration for a focus adjustment mechanism.

FIG. 6 is a flowchart provided for describing a focus position determining method.

FIG. 7 is a flowchart showing a subroutine of an automatic movement process in the flowchart of FIG. 6;

FIG. 8 is a diagram for explaining parameters of a vibration pattern set in a focusing position automatic movement program.

FIG. 9 is a diagram used for describing a focus position automatic movement operation.

FIG. 10 is an explanatory diagram showing a schematic configuration of a production line to which another embodiment of the present invention is applied.

FIG. 11A is an explanatory view showing a state in which a processing point is focused before scanning by a scanning mirror, and FIG.
FIG. 11B is an explanatory view showing a state after the scanning by the scanning mirror and a new processing point is not focused, and FIG.
FIG. 5 is an explanatory diagram showing a state in which a focusing optical unit is operated after scanning by a scanning mirror to focus on a new processing point.

12A is an explanatory view showing a state where the processing point is in focus, FIG. 12B is an explanatory view showing a state where the focus is before the processing point, and FIG. It is an explanatory view showing a state on the side.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Production line 14 ... Master controller 16 ... Robot controller 18 ... Welding robot 20 ... Laser control panel 22 ... CPU 38 ... Teaching box 38E ... Vibration key 42, 42A-42D ... Operation mode changeover switch 50 ... Laser oscillator 52 ... Processing head 54 ... laser shutter 56 ... scanning optical system 56A ... focusing optical means 56B ... scanning optical means 58 ... optical system driving motor 62 ... laser pointer 74 ... imaging processing circuit 76 ... video camera 120 ... optical surface plate 122 ... parabolic mirror 124 Reference numerals 126, focus adjusting mirror 128, elliptical mirror 131, X-axis scanning mirror 132, Y-axis scanning mirror Bs, bright spots J, J1, J
2 ... Processing point L ... Laser light L1 ... Welding laser light Lp ... Processing point instruction laser light T1 ... Vibration cycle V1 ... Vibration amplitude TCP ... Tool center point VT ... Vibration pattern W ... Workpiece

Continued on the front page (72) Inventor Yoshiharu Sakai 1-10-1 Shinsayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd.

Claims (3)

[Claims] 1. A laser processing apparatus which focuses a processing laser beam output from a laser oscillator to a desired position on a workpiece via a focusing optical means and a scanning optical means, and performs processing at the focusing position. A processing point instruction that is arranged on the optical axis of the processing laser light in place of the processing laser light and that outputs a processing point instruction laser light that is a visible laser light that indicates a processing point of the workpiece; A laser light oscillator for automatically moving a focusing position of the processing point indicating laser light on the workpiece adjusted by the focusing optical means with a constant amplitude in a front-rear direction of an irradiation direction of the workpiece. And a focusing position automatic moving means. 2. An apparatus according to claim 1, further comprising: an image pickup means for picking up an image of a luminescent spot of the processing point indicating laser light on the workpiece, and outputting an image pickup signal. Operating, when detecting a focus position at which the size of the luminescent spot of the processing point instruction laser beam is minimized from an image signal picked up by the image pickup means, stopping the operation of the focus position automatic moving means. A laser processing apparatus characterized by the above-mentioned. 3. A laser processing apparatus which focuses a processing laser beam output from a laser oscillator at a desired position on a workpiece via a focusing optical means and a scanning optical means, and performs processing at the focusing position. In the convergence position determination method, a processing point indicating laser that outputs a processing point indicating laser light that is a visible laser light that indicates a processing point instead of the processing laser light on the optical axis of the processing laser light. An optical oscillator is arranged to align the optical axis, and the irradiation position of the processing point indicating laser light is temporarily adjusted to a position to be processed on the workpiece by operating the scanning optical means, and the temporary position is used as a reference. Wherein the focusing optical means is operated so that the focusing position automatically moves in the front-rear direction of the irradiation direction to determine the focusing position of the processing point indicating laser light. Focusing position determination method in the.