JPH0557470A - Laser beam processing method and device - Google Patents

Abstract

PURPOSE:To allow a work to be diagonally cut by laser beam processing. CONSTITUTION:A laser head is inclined with the work 4 and the work is irradiated diagonally with the laser beam (optical axis 1a). A nozzle 2 is inclined at this time to incline the central axis 2a of the nozzle smaller than the optical axis 1a of the laser beam so that the assist gas injected from the nozzle 2 hits onto a cutting surface 4a and to facilitate the supply of the assist gas to a cutting groove. The position where the laser optical axis 1a passes the nozzle hole is set nearer the work side than the central position of the nozzle hole, by which the assist gas is more easily supplied to the cutting groove. The work is diagonally cut in this way. Further, the positioning of the nozzle is facilitated by inclining the laser head in the progressing direction of the cutting point. Since the work can be diagonally cut, a structure can be built by cutting the work at a groove angle and welding the cut work as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method and a processing apparatus for cutting a steel plate or the like by laser light.

[0002]

2. Description of the Related Art Cutting processing using a laser for irradiating a surface of an object to be processed such as a steel plate with a laser beam to melt and cut the object has been conventionally performed. In recent years, with the increase in output of laser oscillators and the progress of laser processing technology, it has become possible to perform cutting processing on thick steel plates using a laser. Further, the steel plate cut by the laser processing device is often further welded and used for constructing a structure, and when the thickness of the steel plate increases, a groove is formed on the end face to be welded in order to obtain a large penetration. It is necessary to weld after performing (processing to make the cut surface oblique). However, in the conventional laser processing apparatus, it is not possible to perform cutting such that the cut cross section of the work piece becomes oblique, and it is possible to cut only in a direction perpendicular to the work piece such as a steel plate. Therefore, a steel plate cut by laser processing is machined to perform groove processing, and then welded to construct a structure.

[0003]

FIG. 4 (b) is a view for explaining a cutting process of a steel sheet by a conventional laser processing apparatus. If the laser beam 1 and the center lines 1a and 2a of the auxiliary gas flow do not match, Since the flow of the gas 3 is biased, dross occurs and good cutting cannot be obtained. Therefore, the optical axis (center axis) 1a of the laser beam 1 and the nozzle hole center line 2a of the nozzle 2 are adjusted so that the laser beam 1 and the auxiliary gas (oxygen) from the nozzle 2 with respect to the workpiece 4 are adjusted. Cutting is performed so that 3 hits vertically. On the other hand, when the work piece is cut obliquely, the optical axis 1a of the laser beam 1 and the nozzle hole center line 2a of the nozzle 2 are aligned with each other as in the case where the work piece is cut vertically as described above. And the processing head is simply tilted (even if the optical axis 1a of the laser beam 1 and the nozzle hole center line 2a of the nozzle 2 are tilted according to the cutting angle), the auxiliary gas 3 does not reach the surface of the workpiece 4. Since the components flowing in parallel increase, the sufficient and appropriate auxiliary gas 3 cannot be supplied to the cut surface, and laser cutting is impossible.

For the above reasons, in the conventional laser processing apparatus, the steel sheet cannot be cut obliquely, and the steel sheet is once cut vertically, and then the groove is machined. There are drawbacks that the number of processes increases, the manufacturing cost increases, and the time required for manufacturing also increases. Then, the objective of this invention is providing the laser processing method and processing apparatus which can cut | disconnect a to-be-processed object diagonally by laser processing.

[0005]

According to the present invention, a laser head for irradiating a workpiece with a laser beam is tilted at an arbitrary angle so that the optical axis of the laser beam is tilted for irradiating the workpiece. A rotation driving means is provided, and a nozzle angle adjusting means for inclining the nozzle attached to the tip of the laser head for injecting the auxiliary gas at an arbitrary angle with respect to the optical axis of the laser light is further provided. Nozzle centering means is provided for adjusting the position where the optical axis of the laser beam passes through the nozzle hole by moving it to an arbitrary position. Then, the laser head rotation driving means tilts the laser head at an angle for cutting the workpiece, and further, the optical axis of the laser light is tilted by the tilt nozzle angle adjusting means to tilt the nozzle with respect to the laser head, and the gas injection angle is set to the above laser. The workpiece is obliquely cut such that the angle of light irradiation is smaller than that of the auxiliary gas and the cutting direction intersects with the cutting surface. Further, similarly, the laser head is tilted at an angle for cutting the workpiece, and the position where the optical axis of the laser beam passes through the nozzle hole by the nozzle centering means is closer to the workpiece side than the center position of the nozzle hole. Position and cut the workpiece diagonally. Further, the nozzle is tilted with respect to the laser head, the laser head is tilted at an angle for cutting the workpiece, and the position where the optical axis of the laser beam passes through the nozzle hole by the nozzle centering means is set from the center position of the nozzle hole. Move to a position close to the side. Further, a means for inclining the laser head in the traveling direction of the cutting point is provided, and by this means, the optical axis of the laser light is inclined forward or backward in the traveling direction of the cutting point for processing.

[0006]

The laser head is tilted at an angle (groove angle) for cutting the workpiece so that the optical axis of the laser light coincides with the cutting angle. Then, the auxiliary gas is supplied to the cutting groove so that the auxiliary gas ejected from the nozzle is tilted with respect to the laser head and hits the cutting surface. This allows the workpiece to be cut obliquely. Also, by setting the optical axis of the laser beam tilted at the same angle as the cutting angle of the work piece to be closer to the work piece side than the center position of the nozzle hole, the auxiliary gas injected from the nozzle is cut into the cutting groove. The workpiece is cut obliquely by making the supply smooth.

Further, the nozzle is tilted with respect to the laser head,
In addition, the optical axis of the laser beam is located closer to the work piece side than the center position of the nozzle hole, so that the auxiliary gas is more smoothly supplied to the cutting groove, thereby cutting the work piece obliquely. Furthermore, tilting the optical axis of the laser light forward or backward in the direction of travel of the cutting point has the effect of increasing the allowable range for the position where the optical axis of the laser light passes through the nozzle hole, making it easier to move the workpiece. Can be cut diagonally.

[0008]

1 is a sectional view of a main part of a laser beam transmission device 10 which is a main part of the present invention. In the figure, 11 is a first transmission pipe for transmitting a laser beam 1 from a laser oscillator (not shown), and the first transmission pipe 11 has a second transmission pipe 15 rotatable through a bearing 14. Is bound to. Also,
A servomotor M for driving the A-axis is provided in the first transmission pipe 11.
a is fixed. A gear 12 is fixed to the rotor shaft of the servomotor Ma, and the gear 12 and the gear 13 fixed to the second transmission pipe 15 are meshed with each other.
The second transmission pipe 15 can be rotated about the central axis of the first transmission pipe 11 in a direction indicated by an arrow A in the figure by driving the axis driving servomotor Ma. The second transmission pipe 15 is bent at a right angle, and a reflecting mirror 16 for reflecting the laser beam 1 at a right angle is provided at the bending point. At the other end of the second transmission pipe 15, a third transmission pipe 19 is rotatably supported by a bearing 21 and a reflecting mirror 20 for bending the laser light at a right angle is provided. .. A gear 18 is fixed to the third transmission pipe, and the gear 18 is fixed to the rotor shaft of the B-axis driving servomotor Mb.
It meshes with 7. Servo motor Mb for driving the B-axis
Is fixed to the second transmission pipe 15, and the B-axis driving servomotor Mb allows the third transmission pipe 19 to rotate in the direction of arrow B in the figure.

A fourth transmission pipe 22 is further fixed to the third transmission pipe 19. A lens 26 for condensing the laser light 1 is provided inside the fourth transmission tube 22. The other end of the fourth transmission pipe 22 is provided with a fitting groove into which the flange portion of the fifth transmission pipe 27 is slidably fitted, and linear actuators 23x, 23y for centering the nozzles in directions orthogonal to each other. (Not shown) is attached to the peripheral portion, and a spring is provided between the flange portion of the fifth transmission pipe 27 and the wall surface of the fitting groove of the fourth transmission pipe 22 at a position facing the linear actuators 23x and 23y. 25 are arranged respectively. Each linear actuator 23x, 23
y is equipped with a servomotor and a screw-nut mechanism for converting the rotational movement of the servomotor into a linear movement,
And the push-out rod 24 and the spring 25 move the fifth transmission pipe 27 in parallel. That is, the fifth transmission pipe 27 is translated in the left-right direction in FIG. 1 by driving the linear actuator 23x, and is translated in the direction perpendicular to the paper surface of FIG. 1 by the unillustrated linear actuator 23y.

The nozzle 2 is attached to the other end of the fifth transmission pipe 27 by a gimbal mechanism 30. In addition, the flange portion at the other end of the fifth transmission pipe 27 is separated by 90 degrees from the nozzle angle adjusting linear actuators 28a,
28b (not shown) is attached, and springs 29 are provided between the flange portion of the fifth transmission pipe 27 and the nozzle 2 at positions facing the linear actuators 28a and 28b. Linear actuators 28a, 28b
Is composed of a servomotor and a screw-nut mechanism that converts the rotational movement of the servomotor into a linear movement.
1 comes into contact with the nozzle 2, and the nozzle 2 can be tilted at an arbitrary angle with respect to the optical axis of the laser light (center line of the laser light) by the amount of advance of the push rod 31 and the spring 29. ing. Reference numeral 4 is a workpiece, 32 is a packing, and 33 is a supply port for supplying an auxiliary gas (oxygen) to the nozzle 2. Further, in the above embodiment, the third, fourth, and
The fifth transmission pipes 19, 22, 27 and the nozzle 2 constitute a laser head, and the B-axis driving servomotor constitutes a laser head rotation driving means.

FIG. 2 is a block diagram of a control system of the laser processing apparatus in this embodiment. Reference numeral 50 is a numerical controller for controlling the laser processing apparatus.
Servo motors 23mx and 23my, which are drive sources for the nozzle centering linear actuators 23x and 23y, servo motors 28ma and 28mb, which are drive sources for the nozzle angle adjusting linear actuators 28a and 28b, and A axis drive servo motors Ma and B axis drives. It is connected to the servo motor Mb, the laser processing machine 51, and the laser oscillator 52. The machine 51 has a servo motor that moves the laser head relative to the workpiece 4 on the XY plane and a servo motor that moves relative to the workpiece 4 in the direction perpendicular to the XY plane.

With the above construction, if the A-axis driving servomotor Ma is driven, the second to fifth transmission pipes 15, 19,
The nozzles 22 and 27 and the nozzle 2 move on a circular orbit centered on the central axis of the first transmission pipe 11. When the B-axis driving servomotor Mb is driven, the laser head, that is, the third, fourth, and fifth transmission pipes 19, 22, 27 and the nozzle 2 rotate about the B-axis in FIG. The head can be tilted with respect to the workpiece. When the laser head is tilted, the laser light applied to the work piece 4 is applied to the work piece 4 at the same tilt angle as the laser head.

Further, the servo motors 23mx, 23my are driven to drive the nozzle centering linear actuator 23x,
By driving 23 y by moving the fifth transmission pipe 27 of the laser head in parallel, the position where the optical axis (center axis of laser light) 1 a of the laser light passes through the nozzle hole of the nozzle 2 is set to an arbitrary position. Can be positioned.
Further, by driving the servo motors 28ma and 28mb to drive the nozzle angle adjusting linear actuators 28a and 28b, the inclination of the nozzle 2 with respect to the fifth transmission pipe 27 can be changed. That is, by changing the inclination of the central axis 2a of the nozzle 2 with respect to the optical axis 1a of the laser light, the injection direction of the auxiliary gas injected from the nozzle can be set to an arbitrary angle.

Therefore, as shown in FIG. 4B, when the workpiece 4 is cut vertically, the nozzle centering linear actuators 23x and 23y are driven to adjust the optical axis position to the nozzle center position. Then, the nozzle angle adjusting linear actuators 28a and 28b are driven to make the inclination of the nozzle (the inclination of the nozzle center axis 2a) coincide with the direction of the optical axis 1a of the laser light, and the laser processing is started.

Further, when the workpiece is cut obliquely, the laser head is tilted for processing. FIG. 3 shows the inclination of the laser head (the optical axis 1 of the laser beam when performing the groove processing.
(a inclination of a) and the inclination of the nozzle 2 (inclination of the nozzle center line 2a), showing a cutting processing state obtained by performing processing, and is the same as when cutting the workpiece 4 vertically. Conditions (when the tilt of the laser beam and the tilt of the nozzle are matched)
When the laser head is tilted at the same angle as the cutting angle θ to perform the cutting process, the dross 5 is stuck between the cutting surfaces as shown in FIG. Further, as shown in FIG. 3B, when the inclination of the laser head (the inclination of the optical axis 1a of the laser beam) is set to the cutting angle θ and the inclination ω of the nozzle 2 is set to be larger than the cutting angle θ, the laser Light cannot penetrate the work piece and cannot be cut. On the other hand, as shown in FIGS. 3C and 3D, when the inclination ω of the nozzle 2 is made smaller than the inclination θ (cutting angle) of the laser head, the nozzle 2 is changed from the nozzle 2 as shown in FIG. The injected auxiliary gas is injected not in parallel to the cutting surface 4a but in a direction of contacting the cutting surface, and the auxiliary gas is sufficiently supplied to the cutting groove, so that the dross 5 is removed and good cutting can be performed. Although the dross always adheres to the side of the cutting surface 2b where the cutting surface is downward, this dross can be easily dropped.

As described above, the optical axis of the laser beam, that is, the inclination of the laser head is set as the cutting angle θ, and the inclination ω of the nozzle 2 is set.
Is determined experimentally to a value (smaller than θ) that allows optimum cutting according to the thickness and material of the steel plate to be cut, and the cutting angle θ, and if the value is set to this calculated value and laser processing is performed, Can cut at any cutting angle. Further, it was experimentally confirmed that this cutting can be processed more favorably by giving the laser head a forward or backward advancing angle along the direction of travel of the cutting point.

FIG. 5 is an explanatory view of this advancing angle, showing a case where the cutting direction is the Y-axis direction.
As shown in (a), it is inclined at a cutting angle θ on a plane parallel to the XZ plane, and further, as shown in FIG. 5 (b),
It has been confirmed by experiments that tilting on the plane parallel to the YZ plane which is the cutting direction by the advance angle φ has the effect of increasing the allowable range for the position where the optical axis of the laser beam passes through the nozzle hole. It was The optimum value for this forward angle is also experimentally obtained in advance. This advance angle φ is A
It is obtained by rotating the shaft and the B-axis.

Further, in the above example, the inclination φ of the nozzle 2 is made smaller than the inclination θ of the laser head (the optical axis of the laser beam) so that the auxiliary gas hits the cut surface, which is the cut surface, for processing. Although an example is shown, as a method of obtaining the same effect as the method of changing the angle, the workpiece can be cut obliquely by adjusting the position where the optical axis 1a of the laser light passes through the nozzle hole. That is, the same effect can be obtained by setting the position where the optical axis 1a of the laser passes through the nozzle hole away from the workpiece 4 from the center position of the nozzle hole. Also in the examples shown in FIGS. 3C and 3D, although the position of the optical axis 1a of the laser light in the nozzle hole and the position of the nozzle center line 2a are different, the inclinations θ and ω are the same and the optical axis of the laser is By performing processing with the nozzle center line 2a position away from the workpiece 4 from the position 1a, the workpiece can be obliquely cut so that the auxiliary gas can be sufficiently supplied to the cutting groove.

Further, by changing the inclination θ of the laser head and the inclination φ of the nozzle, changing the nozzle position with respect to the optical axis 1a of the laser beam, and further giving an advance angle, the work piece can be optimally inclined. A cutting process for cutting can be obtained.

Therefore, general processing conditions such as cutting angle θ, advancing angle φ, nozzle attitude (nozzle inclination angle ω), nozzle position, feed rate, selection of auxiliary gas, laser output, etc. are set in the NC program. After setting, loading the NC program into the numerical controller 50, and executing the program,
The numerical controller 50 drives the B-axis driving servomotor Mb to incline the laser head at the cutting angle θ, and further drives the A-axis and B-axis.
The axis driving servomotors Ma and Mb are driven to give a forward angle φ to the laser head. Then, the nozzle centering linear actuators 23x and 23y are driven to drive the fifth transmission pipe 2
7 is moved to position the nozzle position at the set value, and the nozzle angle adjustment linear actuators 28a, 2
8b is driven and the nozzle 2 is tilted to the set value ω. Then, the X, Y, and Z axis servomotors of the machine are driven to position the laser head at the processing start position, and the cutting processing is started.

The cutting angle θ, the advancing angle φ, the nozzle attitude (nozzle inclination angle ω), and the nozzle position are not set by the program, and the advancing angle φ that allows optimum cutting processing according to the cutting angle θ in advance, The posture of the nozzle (nozzle inclination angle ω) and the nozzle position are set and stored in the memory of the numerical control device 50, and the cutting angle is simply set to correspond to the set cutting angle θ. The stored advance angle φ,
The nozzle posture (ω) and the nozzle position may be read out and automatically set. Further, in the case of cutting for the purpose of cutting a plurality of specific cutting angles, an appropriate nozzle may be created in advance, and the cutting process may be performed by replacing the nozzle according to the cutting angle. .. In this case, it is not necessary to provide the nozzle angle adjusting linear actuators 28a and 28b and the nozzle centering linear actuators 23x and 23y.

Further, in the above embodiment, the linear movement of the nozzle centering and the linear actuator for adjusting the nozzle angle are converted into the linear movement of the servo motor to continuously change the nozzle position and the inclination angle of the nozzle. Although the position and angle of the nozzle are determined according to the type of cutting angle to be processed, the nozzle centering linear actuator and the nozzle angle adjusting linear actuator have a plurality of nozzle positions. A linear actuator may be used that allows multiple positioning to be angular.

[0023]

According to the present invention, a process for obliquely cutting a work piece that cannot be conventionally processed is jetted from a nozzle in the optical axis direction of the laser beam (the direction in which the work piece is cut). The auxiliary gas strikes the cutting surface by changing the injection direction of the auxiliary gas so that the auxiliary gas is more supplied to the cutting groove, or the position where the optical axis of the laser beam passes through the nozzle hole is set. A position closer to the work piece side than the center position of (3) is adopted so that the auxiliary gas is easily supplied to the cutting surface so that the work piece can be cut obliquely. Therefore, when constructing a structure by further welding cut steel plates and the like, the groove angle is laser-processed without performing machining to obliquely cut the steel plates and the like again to form a groove for welding. If the steel plate is cut with, it is not necessary to perform the processing again, the man-hour is reduced, the work efficiency is improved, and the structure can be constructed at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a laser light transmission device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control system of the laser processing apparatus in the embodiment.

FIG. 3 is a diagram showing a cutting processing state due to a tilt of a laser head and a tilt of a nozzle when a workpiece is obliquely cut.

FIG. 4 is an enlarged view of a processing portion when cutting a workpiece.

FIG. 5 is an explanatory diagram of an inclination and a forward angle of a laser head.

[Explanation of symbols]

 1 laser light 1a optical axis of laser light 2 nozzle 2a central axis of nozzle 3 auxiliary gas 4 workpiece 10 laser beam transmission device 16, 20 reflecting mirror 26 lens Ma A-axis driving servo motor Mb B-axis driving servo motor 23x Nozzle centering linear actuator 28a Nozzle angle adjustment linear actuator

Claims (8)

[Claims] 1. A laser processing method for irradiating a workpiece with laser light to cut the workpiece, wherein an irradiation angle of the laser light to the workpiece is adjusted to a cutting angle for cutting the workpiece, and A laser processing method characterized in that an auxiliary gas jetting angle from a nozzle is made smaller than the laser beam irradiation angle, and a workpiece is obliquely cut so that a jetting direction of the auxiliary gas and a cutting surface intersect. 2. A laser processing method for irradiating a workpiece with a laser beam to cut the workpiece, the irradiation angle of the laser beam to the workpiece is adjusted to a cutting angle for cutting the workpiece, and The workpiece is obliquely cut by making the position where the optical axis of the laser beam passes through the nozzle hole closer to the workpiece side than the center position of the nozzle hole so that the auxiliary gas is easily supplied to the cutting surface. A laser processing method characterized by the above. 3. A laser processing method for irradiating a work piece with laser light to cut the work piece, wherein an irradiation angle of the laser light to the work piece is adjusted to a cutting angle for cutting the work piece, The auxiliary gas injection angle from the nozzle is smaller than the laser beam irradiation angle, and the position where the optical axis of the laser beam passes through the nozzle hole is closer to the workpiece side than the center position of the nozzle opening, A laser processing method characterized in that a workpiece is cut obliquely. 4. The object to be processed is irradiated with the laser light by inclining the optical axis of the laser light in the traveling direction of the cutting point.
Alternatively, the laser processing method according to claim 3. 5. A laser processing apparatus for irradiating a workpiece with laser light to cut the workpiece, wherein a laser head for irradiating the workpiece with laser light is tilted at an arbitrary angle. A laser head rotation drive means for irradiating a workpiece with an optical axis inclined and a nozzle for injecting an auxiliary gas attached to the tip of the laser head at an arbitrary angle with respect to the optical axis of the laser light. A laser processing apparatus having an angle adjusting means. 6. A laser processing apparatus for irradiating a workpiece with laser light and cutting the workpiece, wherein a laser head for irradiating the workpiece with laser light is tilted at an arbitrary angle. The position of the laser head rotation driving means for irradiating the workpiece with the optical axis inclined and the position of the nozzle for injecting the auxiliary gas attached to the tip of the laser head are moved to arbitrary positions so that the optical axis of the laser light is changed. A laser processing apparatus comprising: a nozzle centering unit that adjusts a position of passing through a nozzle hole. 7. In a laser processing apparatus for irradiating a workpiece with laser light and cutting the workpiece, a laser head for irradiating the workpiece with the laser light is tilted at an arbitrary angle to emit the laser light. A laser head rotation driving means for inclining and irradiating a workpiece, and a nozzle angle adjusting means for inclining a nozzle attached to the tip of the laser head for injecting an auxiliary gas at an arbitrary angle with respect to the optical axis of the laser beam. And a nozzle centering means for adjusting the position where the optical axis of the laser beam passes through the nozzle hole by moving the nozzle position for ejecting the auxiliary gas attached to the tip of the laser head to an arbitrary position. Processing equipment. 8. The laser processing apparatus according to claim 5, further comprising means for tilting the laser head in a traveling direction of a cutting point.