JP2003181674A - Laser processing machine and method for copying control - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a collision of a laser processing head with an opening edge of a work by surely conducting cancelling of a Z-axis copying control at a work opening passing time even when a Z-axis operation is accelerated in association with acceleration of a feeding speed of an X-axis or a Y-axis such as high-speed cutting or the like. <P>SOLUTION: A method for copying control comprises the steps of cancelling the Z-axis copying control at the work opening passing time, and moving the laser processing head 11 in the Z-axis direction removing from a work surface at the copying control cancelling time. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing machine and a copying control method, and more particularly to a laser processing machine and a copying control method for performing Z-axis copying control.

[0002]

2. Description of the Related Art In a laser processing machine for cutting and the like, a laser processing head and a work (material) on a work table are relatively moved in the X-axis direction and the Y-axis direction.
The Z-axis gap (up-down gap) between the tip nozzle of the laser processing head and the upper surface of the work is set to a predetermined value so that the work is irradiated with the laser beam from the laser processing head in a predetermined state such as a focused state. Need to keep.

Therefore, in the laser processing machine,
The distance between the tip nozzle of the laser processing head and the work surface (distance in the Z-axis) is measured by a capacitance type or eddy current type non-contact type distance sensor provided in the laser processing head. Based on the Z-axis control of the laser processing head based on this, Z-axis scanning control is performed to perform laser processing such as laser cutting while maintaining the gap between the tip nozzle of the laser processing head and the upper surface of the work at a predetermined value.

By this Z-axis scanning control, even if the workpiece has warp, undulation, distortion, etc. and the workpiece upper surface position is not stable, a gap in the Z-axis direction between the tip nozzle of the laser processing head and the workpiece upper surface is obtained. Stable and good laser processing can be performed while maintaining the predetermined value.

When the workpiece has an opening such as a hole and the laser processing head moves across the opening, the workpiece upper surface does not exist at the opening, so that the Z-axis copying control is performed even when passing through the opening. Since the laser processing head drops abnormally, the edge of the workpiece opening (opening edge) is detected from the measurement value of the distance sensor, and the Z-axis scanning control is canceled when the workpiece passes through the opening.

[0006]

In the case of high speed cutting, X
The Z-axis copying control without delay will not be performed unless the Z-axis operation is also increased by the amount of increase in the feed rate of the axis and the Y-axis.

Therefore, in the case of high-speed cutting, the Z-axis scanning control becomes fast and sensitive, and as shown in FIG. 6, from the detection of the edge Wef of the workpiece opening Wh to the cancellation of the Z-axis scanning control. The Z-axis descending amount in the time lag period Tr increases as the Z-axis speed increases, and the Z-axis position Z of the laser processing head 100 after the Z-axis scanning control is canceled.
h is lower than the workpiece upper surface position Zw. Therefore, after the laser processing head 100 passes through the work opening Wh, the tip nozzle portion of the laser processing head 100 collides with the facing work opening end edge Weo.

This is because the balance variation between the control speed of the Z-axis scanning control and the operating speed of each axis and the non-uniformity of the edge of the work opening make the distance sensor sensitive to the sensing of the work opening end. What can't be done becomes more prominent.

The present invention has been made in order to solve the above-mentioned problems, and even if the Z-axis operation becomes faster as the X-axis and Y-axis feed rates become faster due to high-speed cutting and the like, the Z-axis operation becomes faster. It is an object of the present invention to provide a laser processing machine and a copying control method in which scanning control, in particular, Z-axis scanning control when passing through a workpiece opening is accurately canceled, and a laser processing head does not collide with the edge of the workpiece opening. There is.

[0010]

To achieve the above object, a laser beam machine according to the present invention moves a laser beam machining head and a workpiece on a work table relatively in the X axis direction and the Y axis direction. At the same time, the distance between the tip nozzle of the laser processing head and the work surface is measured, and the Z-axis control of the laser processing head based on the measured value is performed to perform a copy control for maintaining the gap between the tip nozzle and the work surface at a predetermined value. In the laser processing machine for performing the laser processing, the copying control is canceled when the work passes through the opening, and the laser processing head is moved in the Z-axis direction away from the work surface when the copying control is canceled.

In order to achieve the above object, the scanning control method according to the present invention is such that the laser machining head and the workpiece on the workpiece table are moved relatively in the X-axis direction and the Y-axis direction while the laser processing head is being moved. The distance between the tip nozzle of the processing head and the work surface is measured, and the laser beam is controlled by the Z-axis control of the laser processing head based on the measured value so that the gap between the tip nozzle and the work surface is kept at a predetermined value. In the copying control method for processing, the copying control is canceled when the work passes through the opening, and the laser processing head is moved in the Z-axis direction away from the work surface when the copying control is canceled.

According to the laser processing machine and the copying control method of the present invention, when the copying control is canceled, the laser processing head is moved in the Z-axis direction away from the work surface. Therefore, from the detection of the edge of the work opening to the cancellation of the copying control. Even if the movement amount of the laser processing head during the time lag period increases as the scanning control speed increases, the laser processing head position (nozzle tip surface position) after canceling the scanning control falls below the work surface position (overlap). ) Is avoided.

When canceling the copying control, the amount of movement of the laser processing head in the Z-axis direction away from the work surface can be determined according to the axis feed speed in the X-axis direction and the Y-axis direction. Only when the head is displaced toward the work side by a predetermined amount or more, that is, only when there is a possibility that the laser processing head collides with the work opening edge, the laser processing head is moved from the work surface at the time of canceling the copying control. It can also be moved away from the Z-axis.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows one embodiment of a laser processing machine according to the present invention. The laser processing machine 1 includes a U-shaped frame 3. The frame 3 includes a lower frame 5, an upper frame 7, and a side frame 9 connecting the lower frame 5 and the upper frame 7.

A laser processing head 11 is provided on the upper frame 7.
Are provided so as to be axially movable in the Z-axis direction (vertical direction). A laser beam is applied to the laser processing head 11 from a laser oscillator (not shown), and an assist gas is supplied from an assist gas supply source (not shown).

A work supporting and moving device 13 is provided on the lower frame 5. The work supporting / moving device 13 includes a center table 15 fixedly arranged on the lower frame 5.
A side table 17 arranged on both sides of the center table 15 and movable in the Y-axis direction;
Side tables 17 on both sides extending in the X-axis direction
And a carriage base 19 fixedly connected to.

The carriage 21 has a carriage 21.
Is provided so as to be movable in the X-axis direction, and the carriage 2
A work clamp 23 for clamping a work (plate material) W on the table is attached to the table 1.

The work W clamped by the work clamp 23 moves in the X-axis direction when the carriage 21 moves in the X-axis direction, and moves in the Y-axis direction when the side table 17 moves in the Y-axis direction. This X axis movement and Y
By the axial movement, the processing position of the work W can be moved to a position directly below the laser processing head 11, and the laser beam is emitted from the tip nozzle 25 (see FIG. 2) of the laser processing head 11 along with the assist gas injection and the processing of the work W. Laser cutting is performed by irradiation toward the processing position.

On the side frame 9 side, a cabinet 33 of a numerical controller (CNC) 31 for controlling the laser beam machine 1 is provided adjacent to the press body. An NC operation panel 35 and a display 37 with a touch sensor panel are attached to the cabinet 33.

The control system of the laser processing machine 1 will be described with reference to FIG. The laser processing machine 1 drives an X-axis servomotor 39 that drives the carriage 21 in the X-axis direction, a Y-axis servomotor 41 that drives the side table 17 in the Y-axis direction, and drives the laser processing nozzle 11 in the Z-axis direction. It has a Z-axis servomotor 43. Servo motors 39 and 4 for each axis
Motor position detectors 45, 47, 49 such as rotary encoders are attached to the motors 1, 43.

The CNC 31 has motor position detectors 45, 4
A motor position signal is input from each of 7 and 49, and each control axis (X
(Axis, Y-axis, Z-axis), and outputs a control signal to the laser output control unit 51 and the assist gas control unit 53.

A distance sensor 55 is attached to the tip nozzle 25 of the laser processing head 11 to measure the distance between the tip nozzle 25 and the upper surface of the work in the Z-axis direction in a non-contact manner by electrostatic capacitance or eddy current. The CNC 31 includes a copying control unit 57.

The copying control unit 57 performs Z-axis control by the Z-axis servo motor 43 of the laser processing head 11 on the basis of the measured value of the distance between the tip nozzle 25 and the workpiece upper surface measured by the distance sensor 55 in the Z-axis direction. , Tip nozzle 2
The Z-axis scanning control is performed to keep the gap between the workpiece 5 and the upper surface of the work at a predetermined value set in advance by a parameter.

The copying control unit 57 detects the edge of the opening of the work W from the value measured by the distance sensor 55, cancels the copying control when passing through the opening, and when canceling this copying control, the laser machining head 11 is moved to the work. Control is performed to move in the Z-axis direction away from the upper surface, that is, the + Z-axis direction in which the laser processing head 11 moves upward.

The amount of movement for moving the laser processing head 11 in the + Z-axis direction when canceling the copying control is in the X-axis direction and the Y-axis direction.
It can be determined according to the axial feed speed in the axial direction. The higher the axial feed speed in the X-axis direction and the Y-axis direction, the larger the + Z-axis direction movement amount may be set.

Further, the laser processing head is located on the work side (-Z
The laser processing head 11 may be moved in the + Z-axis direction at the time of canceling the scanning control, only when it is displaced downward by a predetermined amount in the axial direction).

Next, the Z-axis scanning control process will be described with reference to FIGS.
Will be described with reference to.

The scanning control routine shown in FIG. 3 is repeatedly executed every predetermined time (several msec).

First, the Z-axis scanning sensing information is read (step S11). The Z-axis scanning sensing information is a measurement value by the distance sensor 55, the measurement value is fetched by the distance sensor 55 at predetermined sampling time intervals, and the measurement value is stored in time series as Z-axis scanning sensing information.

Next, it is judged from the Z-axis scanning sensing information whether or not the upper surface of the material is displaced (step S12).
If there is displacement on the upper surface of the material, it is determined whether or not the copying control flag is on (step S13). The copying control flag is turned on and off by the copying control on / off routine shown in FIG. 4. When the copying control flag is on, Z-axis copying control is executed and the copying control flag is set. If is off, the Z-axis scanning control is stopped, that is, cancelled.

If the copying control flag is on, the conventional Z
Similar to the axis scanning control, it is determined from the Z axis scanning sensing information whether the height position (Z axis position) of the tip nozzle 25 with respect to the work upper surface is higher than the steady position (step S14). If it is high (that is, if the distance between the work W and the processing head 25 is larger than a predetermined value), the laser processing head 11 is moved in the −Z axis direction (Z axis − direction) (step S15). If it is lower than the position (that is, the distance between the work W and the processing head 25 is smaller than a predetermined value), the laser processing head 11 is moved in the + Z-axis direction (Z-axis + direction) (step S16). As a result, the position of the laser processing head 11 in the Z-axis direction converges to the steady position while the scanning control flag is on.

On the other hand, if the scanning control flag is OFF, in other words, when the workpiece W passes through the opening, the laser processing head 11 is obtained from the Z-axis position information obtained from the motor position signal of the motor position detector 49. Z-axis position of is a predetermined value,
For example, it is determined whether the position is lower than the work top surface position (step S17).

This means to judge whether or not the laser processing head 11 is displaced toward the work side by a predetermined amount or more when the copying control is canceled, and the Z-axis position of the tip nozzle 25 of the laser processing head 11 is the work top surface position. If it is lower, the Z-axis position of the laser processing head 11 is increased by a predetermined amount in the + Z-axis direction (Z-axis +
Control to move upward in the direction (step S1)
8).

The predetermined amount in the + Z-axis direction of the laser processing head 11 at this time is determined by the Z-axis position of the laser processing head 11 and the X-axis position.
The tip nozzle 2 according to the axial feed speed in the axial direction and the Y-axis direction
5 is set to an amount that is located above the work top surface position.

Next, the copying control on / off routine shown in FIG. 4 will be described. The scanning control ON / OFF routine is repeatedly executed at predetermined time intervals (several msec), and first, Z-axis scanning sensing is performed (step S2).
1). This is the acquisition of the measurement value by the distance sensor 55, and based on the measurement value by the distance sensor 55, it is determined whether or not the position below the tip nozzle 25 of the laser processing head 11 (the position directly below) is the material edge. (Step S2
2).

The detection of the material edge here is the detection of the opening edge Wef or Weo (see FIG. 5) of the opening Wh of the work W. When the material edge is detected, the scanning control flag is turned on. It is determined whether or not there is (step S23).

The initial value of the copying control flag (value at the start of processing) is ON. Therefore, when the copying control flag is turned on, it means that the laser processing head 11 is located in the normal portion other than the opening portion. Therefore, if the scanning control flag is ON in the detection of the material edge (step S23), it is the detection of the front-side opening edge Wef. In this case, it is assumed that the work opening Wh starts to pass. The copying control flag is turned off (step S24).

On the other hand, when the copying control flag is off in the detection of the material edge, it means that the opening edge Weo on the other side is detected. In this case, it is assumed that the work opening Wh has passed and the copying is finished. Turn on the control flag (step S2)
5).

When the scanning control flag is turned off as shown in FIG. 5 by the above Z-axis scanning control, that is, when the Z-axis scanning control is canceled, in the case of high-speed processing, the laser processing head 11 is used. The Z-axis position of No. 2 is lowered to the position indicated by the reference symbol Zd, but immediately the laser processing head 11 is moved upward by the predetermined amount Zset by the + Z-axis movement control. As a result, the tip nozzle 25 of the laser processing head 11 moves to a position above the upper surface of the work W, and the tip nozzle 2 of the laser processing head 11 moves.
It is avoided that 5 collides with the workpiece opening edge Weo.

Then, in the period until the scanning edge flag Weo is detected and the scanning control flag is turned on and the time lag period until the Z-axis scanning control is enabled, the laser processing head 11 moves by a predetermined amount Zset. In the elevated position,
The laser processing head 1 is enabled by enabling the Z-axis scanning control.
1 comes to be in the steady position again.

[0042]

As can be understood from the above description, according to the laser processing machine and the copying control method of the present invention, the laser processing head is moved in the Z-axis direction away from the work surface when the copying control is canceled. Even if the movement amount of the laser processing head increases during the time lag period from the detection of the edge of the opening to the cancellation of the copy control, the nozzle tip surface position after the copy control cancellation is lower than the work surface position even if the copy control speed increases. Without
Even if the Z-axis operation becomes faster as the X-axis and Y-axis feed rates become faster, such as high-speed cutting, the laser processing head does not collide with the workpiece opening edge.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing an embodiment of a laser beam machine according to the present invention.

FIG. 2 is a block diagram showing a control system of the laser processing machine according to the present invention.

FIG. 3 is a flowchart showing a copying control routine in the laser beam machine according to the present invention.

FIG. 4 is a flowchart showing a copying control ON / OFF routine in the laser beam machine according to the present invention.

FIG. 5 is a diagram showing a locus of movement of the laser processing head in the case of the copying control method according to the present invention.

FIG. 6 is a diagram showing a locus of movement of a laser processing head in the case of conventional copying control.

[Explanation of symbols]

1 Laser processing machine 3 frames 11 Laser processing head 31 Numerical Control Unit (CNC) 43 Z-axis servo motor 55 distance sensor 57 Copy Control Unit

Claims (7)

[Claims] 1. The distance between the tip nozzle of the laser processing head and the work surface is measured while moving the laser processing head and the work on the work table relatively in the X-axis direction and the Y-axis direction. In a laser processing machine that performs laser processing by performing a copy control that maintains a gap between the tip nozzle and a work surface at a predetermined value by Z-axis control of the laser processing head based on a value, copy control is performed when a work opening passes. A laser processing machine that cancels and moves the laser processing head in the Z-axis direction away from the work surface when the copying control is canceled. 2. The laser processing machine according to claim 1, wherein when the copying control is canceled, the amount of movement for moving the laser processing head in the Z-axis direction away from the work surface is the X-axis direction.
It is decided according to the axis feed speed in the Y-axis direction. 3. The laser processing machine according to claim 1, wherein the laser processing head is moved away from the work surface when the copying control is canceled, only when the laser processing head is displaced toward the work side by a predetermined amount or more. What is moved in the axial direction. 4. The distance between the tip nozzle of the laser processing head and the work surface is measured while moving the laser processing head and the work on the work table relatively in the X-axis direction and the Y-axis direction. A Z-axis control of the laser processing head based on a value is performed to perform laser control by performing a scanning control for maintaining a gap between the tip nozzle and a work surface at a predetermined value. A copying control method of canceling and moving the laser processing head in the Z-axis direction away from the work surface when canceling the copying control. 5. The copying control method according to claim 4, wherein when the copying control is cancelled, a movement amount for moving the laser processing head in the Z-axis direction away from the work surface is set in the X-axis direction.
It is determined according to the axis feed speed in the Y-axis direction. 6. The scanning control method according to claim 4, wherein the laser processing head is moved away from the work surface when canceling the scanning control, only when the laser processing head is displaced toward the work side by a predetermined amount or more. Move in the axial direction. 7. The laser processing machine according to claim 3, wherein only when the laser processing head is displaced toward the work side by a predetermined amount or more, the laser processing head is moved away from the work surface when the copying control is canceled. End face exploration method of work to be moved in the direction.