JP2000052076A - Laser processing device and processing head driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity by fastening and stabilizing approach of a processing head to a work, and significantly reducing the total processing time. SOLUTION: A gap sensor is installed to a processing head 1, and electrostatic capacity between the processing head tip and a work is detected by the gap sensor. Then, the processing head 1 approaches the work 3 at high velocity till the detected electrostatic capacity reaches a predetermined electrostatic capacity reference value (the electrostatic capacity value at a copy range point). After the detected electrostatic capacity exceeds the electrostatic capacity reference value, the processing head 1 approaches the work 3 at low velocity.

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 and a method of driving a processing head in a laser processing apparatus, and more particularly, to reducing the processing time by stabilizing the approach of a processing head to a work at high speed. And a method of driving a processing head.

[0002]

2. Description of the Related Art As a laser processing apparatus which irradiates a laser beam oscillated from a laser oscillation apparatus together with an assist gas toward the work from the tip of a processing head and cuts the work with the laser light, for example, One disclosed in Japanese Unexamined Patent Publication No. 5-285680 is known.

[0003] The laser processing apparatus is provided with a gap sensor for controlling the processing head to be vertically movable with respect to the work in the Z-axis direction (vertical direction). The gap sensor detects the position of the processing head in the Z-axis direction with respect to the work. Then, based on the position information of the processing head from the gap sensor, the processing head is driven and controlled to be vertically movable with respect to the work.

[0004]

By the way, in the conventional laser processing apparatus, in order to reduce the influence of disturbance noise and stabilize the cutting, when the processing head approaches the work from a high position with respect to the work. The speed (this is called an approach) is set to a low speed that does not rush when approaching the work. Therefore, a total processing time including the approach is required, and the productivity cannot be improved.

Therefore, it is possible to increase the speed only at the time of approach by adjusting the gain. However, if the gain is simply adjusted in the conventional configuration, overshoot occurs and the workpiece is sunk.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for changing the speed of a processing head at a certain point in order to greatly and shorten the total processing time by stabilizing the approach of the processing head to a workpiece at a high speed. I tried to make it.

More specifically, a gap sensor for detecting the capacitance between the tip of the processing head and the work is provided on the processing head. Then, based on the capacitance detected by the gap sensor at each position of the processing head, the distance between the tip of the processing head and the work (this is called a gap)
And these are plotted as a graph (see FIG. 4). According to this graph (characteristic diagram), there is a proportional relationship between the capacitance and the gap, and when the working head is separated from the work by a certain distance or more, the proportional relationship is broken and the gap can be measured. There is a point that disappears (hereinafter, this point is referred to as a scanning range point, and the capacitance value at that time is referred to as a capacitance reference value). Therefore, when the processing head approaches the workpiece, it always passes through the scanning range point.

In the present invention, utilizing this characteristic, the approach speed of the processing head is changed at the scanning range point.
That is, as shown in FIG. 3, the processing head 1 is brought close to the workpiece 3 at a high speed until the scanning range point (capacitance reference value) is reached, and after passing the scanning range point, the processing head 1 is moved at a low speed to the workpiece 3. Approach. Thereby, the approach of the processing head to the workpiece is performed at high speed and stably, and the total processing time is significantly reduced. Here, the high speed refers to a speed that is twice or more the speed of the low speed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

In this embodiment, the present invention is applied to a laser processing apparatus for irradiating a laser beam to cut a work or the like and a processing head driving method used in this apparatus, so that a processing head can approach a work at high speed. In addition, it stabilizes and greatly reduces the total processing time.
Further, the present embodiment is an example of a laser processing apparatus in which a processing head is vertically moved (Z-axis direction) with respect to a workpiece.

First, a laser processing apparatus according to the present embodiment will be described with reference to FIGS. As shown in FIG. 1, the laser processing apparatus according to the present embodiment includes a processing head 1, a gap sensor 5 provided in the processing head 1, a control unit 11 including a controller 7 and a calculation unit 9.
And a Z-axis servo motor 13.

The processing head 1 is, as shown in FIG.
The laser beam oscillated from the laser oscillation device is irradiated from the head end to the work 3 together with the assist gas,
The work 3 is cut by the laser light. The processing head 1 is movable in the Y-axis direction by a carriage (not shown), and the control unit 1
1 is movable up and down in the Z-axis direction by a Z-axis servomotor 13 controlled by the control unit 1.

The work 3 is clamped by a clamper of a work table device (not shown), and is positioned and driven in both the X-axis direction and the Y-axis direction. Alternatively, the processing head 1 moves in the X-axis direction and the Y-axis direction. Further, the X axis moves by the combination of the processing head 1 and the Y axis moves by the combination of the work 3 and the like.

The gap sensor 5 detects the capacitance between the tip of the processing head 1 and the work 3 as shown in FIG. And this gap sensor 5
It is provided near the tip of the processing head 1 and outputs the detection result to the controller 7.

As shown in FIG. 1, the controller 7 obtains a vertical distance (gap) H1 between the tip of the processing head and the work 3 from the capacitance detected by the gap sensor 5, and calculates the result. The data is output to the arithmetic unit 9.

The arithmetic unit 9 is determined in advance at the vertical distance H1 obtained by the controller 7 and a processing position (a command gap position in FIG. 3) at which the processing head 1 performs laser processing on the work 3. The difference from the vertical distance H2 is calculated. The arithmetic unit 9 drives the Z-axis servo motor 13 based on the calculation result, thereby controlling the processing head 1 to be vertically movable.

In the control section 11, as described above, the capacitance detected by the gap sensor 5 reaches a predetermined capacitance reference value (capacitance value at a scanning range point in FIG. 4). Until the processing head 1 approaches the work 3 at high speed (down in this example), the processing head 1 is moved from the point where the detected capacitance exceeds the capacitance reference value. It is controlled so as to approach the work 3 at a low speed.

The change in the lowering speed of the processing head 1 is not performed in a program, but is performed automatically by the calculation unit 9. Therefore, there is no delay due to the program command, and the speed is switched smoothly. It is to be noted that it is possible to issue a command separately to the scanning range point and below the scanning range point in the program. However, in this method, an NC calculation delay occurs and the machining head 1 must be decelerated and stopped at the scanning range point. In addition, the approach of the processing head 1 to the work 3 cannot be performed quickly.

The drive control of the processing head 1 is used only when approaching, and is not performed during actual laser processing. When the processing is performed during laser processing, when the processing head 1 comes to the hole and the end face of the workpiece 3, the capacitance detected by the gap sensor 5 passes through the scanning range point. There is a possibility that the processing head 1 collides with the work 3 and breaks the apparatus.

Next, a method of driving the processing head in the laser processing apparatus having the above configuration will be described with reference to a flowchart shown in FIG.

The flowchart of FIG. 2 starts when the power is turned on in step S1, and in step S2, the Z-axis servo motor 13
Is moved down to the work 3 at high speed. While the machining head 1 is being lowered, the capacitance is always detected by the gap sensor 5, and the vertical distance between the tip of the machining head and the workpiece is obtained from the capacitance by the controller 7.
The calculation unit 9 calculates a difference between the vertical distance and a predetermined vertical distance at the processing position.

Then, in step S3, the control unit 1
1 determines whether or not the capacitance detected by the gap sensor 5 has exceeded the scanning range point (capacitance reference value).
The routine of Step 3 is repeatedly executed, and in the case of YES, the process proceeds to Step S4. That is, the processing head 1 is lowered at high speed until the scanning range point is reached. The above processing head 1
Since the descending speed depends on the Z-axis drive system of the processing machine,
There is no particular preferred speed, but the faster the better. Thus, by controlling the processing head 1, the approach of the processing head 1 to the work 3 can be accelerated.

In step S4, unlike step S2, the machining head 1 is lowered to the work 3 at a low speed by the Z-axis servo motor 13. That is, when the processing head 1 approaches the work 3 to some extent, the processing head 1 is slowly lowered to prevent the processing head 1 from colliding with the work 3. The lowering speed of the processing head 1 here depends on the Z-axis drive system of the processing machine, so there is no particular preferable speed, but a higher speed is better.

Next, the process proceeds to step S5, where
In the above, the machining head 1 is
To reach a predetermined position (command gap position). Then, after positioning the processing head 1 at this position, the processing head 1 performs laser processing on the work 3 based on a processing program.

As described above, the capacitance between the tip of the processing head and the work 3 is detected by the gap sensor 5 provided on the processing head 1, and the detected capacitance is set to a predetermined capacitance reference value. Until the processing head 1 is lowered to the work 3 at a high speed, and when the detected capacitance exceeds the capacitance reference value, the processing head 1 is moved at a low speed to the work 3. 3, the processing head 1 approaches the work 3 at high speed and is stable, and the total processing time can be greatly reduced.
Also, the processing head 1 overshoots and the work 3
No accidents such as rushing into the car will occur.

As described above, a specific embodiment to which the present invention is applied has been described. However, the present invention can be variously modified without being limited to the above-described embodiment.

In the above-described embodiment, the processing head 1 is caused to reach the command gap position by the above-described control method, and the workpiece 3 is subjected to laser processing at that position. However, as shown in the flowchart of FIG. After positioning 1 at the command gap position, this position (the coordinate values of the X axis, Y axis and X axis) is stored in step S6,
Proceeding to step S7, laser processing is performed on the work 3 in this step S7.

Then, in the next approach, it is determined whether or not the processing head 1 is at the first processing start point position.
If it is, the process proceeds to step S9, and if YES, the flow shown in FIG. 2 is repeated. In step S9, it is determined whether or not the X-axis and Y-axis coordinate values of the processing head 1 at the pre-processing position are separated from the X-axis and Y-axis coordinate values of the next processing position by a certain amount or more. If NO, the process proceeds to step S10, and if YES, the flow shown in FIG. 2 is repeated.

In step S10, since the position of the machining head 1 at the pre-machining position is stored, the Z-axis servomotor 13 is driven to, for example, instruct the machining head 1 at the position shown by the dotted line in FIG. Lower by rapid traverse positioning to the gap reaching position.

In this manner, the approach at the portion to be laser-processed next can be made faster. Therefore, the processing head 1 can approach the workpiece 3 at high speed and stably, and the processing time can be greatly reduced.

In the above embodiment, the processing head 1
Is vertically lowered with respect to the work 3, but the present invention is also applicable to a device configuration in which the processing head 1 is caused to approach horizontally by a robot or the like with respect to the work 3 positioned vertically, for example. A similar effect can be obtained.

[0032]

The present invention is embodied in the form described above and has the following effects.

According to the present invention, the capacitance between the tip of the processing head and the work is detected by the gap sensor provided on the processing head, and the detected capacitance is set to a predetermined capacitance reference value. Until the processing head is reached, the processing head is brought close to the work at a high speed, and when the detected capacitance exceeds the capacitance reference value, the processing head is brought close to the work at a low speed. Therefore, the approach of the machining head to the workpiece is fast and stable, the total machining time can be significantly reduced, and the productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a laser processing apparatus according to an embodiment.

FIG. 2 is a flowchart for controlling driving of a processing head in the laser processing apparatus of the present embodiment.

FIG. 3 is a schematic diagram illustrating a positional relationship of a processing head with respect to a work in the laser processing apparatus of the present embodiment.

FIG. 4 is a characteristic diagram showing a vertical distance between a tip of a processing head and a workpiece with respect to capacitance.

FIG. 5 is a flowchart illustrating another example of driving control of the processing head in the laser processing apparatus of the present embodiment.

[Explanation of symbols]

 Reference Signs List 1 processing head 3 work 5 gap sensor 7 controller 9 calculation unit 11 control unit 13 Z-axis servo motor

Claims (4)

[Claims] 1. A gap sensor is provided on a processing head,
The gap sensor detects the capacitance between the processing head tip and the work, and moves the processing head to the work at high speed until the detected capacitance reaches a predetermined capacitance reference value. And a control unit for controlling the processing head to approach the workpiece at a low speed after the detected capacitance exceeds the capacitance reference value. Laser processing equipment characterized by the following. 2. A gap sensor provided on a processing head for detecting a capacitance between a tip of the processing head and a workpiece, and a capacitance detected by the gap sensor is set to a predetermined capacitance reference value. Until the processing head is reached, the processing head is made to approach the work at a high speed, and after the detected capacitance exceeds the capacitance reference value, the processing head is made to approach the work at a low speed. A controller for determining the distance between the tip of the processing head and the work from the capacitance detected by the gap sensor, and a controller for determining the distance from the capacitance detected by the gap sensor. And a calculation unit for calculating a difference between the determined distance and a predetermined distance at a processing position where the processing head performs laser processing on the work. And which laser processing apparatus characterized by comprising close driving the processing head relative to the workpiece based on the calculated result. 3. The characteristic diagram representing the distance between the tip of the processing head and the workpiece with respect to the capacitance detected by the gap sensor at each position of the processing head determined in advance. 3. The laser processing apparatus according to claim 1, wherein the distance and the capacitance value are a region near a maximum value of a range indicating a proportional relationship. 4. A capacitance between the tip of the processing head and the workpiece is detected by a gap sensor provided on the processing head, and the capacitance is detected until the detected capacitance reaches a predetermined capacitance reference value. Controlling the processing head to approach the work at a high speed, and from the point where the detected capacitance exceeds the capacitance reference value, the processing head is controlled to approach the work at a low speed. A method for driving a processing head in a laser processing apparatus.