JP2000033486A - Laser beam machining method and its machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machining method and its machine which prevent defective machining by surely sounding an alarm and which execute a program by automatically detecting the end surface of a work when profiling is abnormal. SOLUTION: In a laser beam machining method wherein a work is machined after executing profiling with a capacitance type sensor prior to laser beam machining, an upper threshold α being a voltage value showing the maximum limit distance between the sensor and the work and a lower threshold β being a voltage value showing the minimum limit distance between the same are preliminarily set in order to execute suitable profiling, and an alarm is sounded and a machine is stopped when a sensor waveform in profiling is continuously more than the upper threshold α or less than the lower threshold β for a specified 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 method and an apparatus therefor, and more particularly to a laser processing method and an apparatus having a feature in scanning in laser processing.

[0002]

2. Description of the Related Art Conventionally, a laser beam machine 1 (see FIG. 2).
In some cases, copying is performed prior to laser processing by a laser beam. This is because, as shown in FIG. 4, the distance H from the work W on the processing table 5 is kept constant (for example, H = 1.5 mm) by a sensor S provided on the processing head 3 or the like. While moving along the processing line, the position and height of the processing head 3 at this time are stored as needed, and in actual processing, the laser processing is performed while moving the processing head to the stored position and height. Is what you do.

[0005] Referring to FIG. 5, when processing is performed from the end face of a work W by a conventional laser processing method, the processing head 3 is moved to the end face of the work W, and He, Ne is processed.
In general, the coordinates of the end face are determined by visual observation using a laser beam LB.

[0004]

However, when copying is performed using the sensor S, when the sensor S contacts the workpiece W, a touch alarm signal is output as a copying abnormality. S and work W
However, there is a problem that an alarm signal cannot be output when the gap amount is not appropriate and causes a processing defect.
Another problem is that an alarm cannot be issued when the sensor S is moving upward due to a sensor failure.

When the coordinates of the end face are determined by visual observation with a He or Ne laser or the like, when the work W is positioned at an arbitrary position, and when the sketch material is processed from the end face, the machining head 3 is manually moved. However, there is a problem that it takes time, the efficiency is low, and accurate positioning cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to pay attention to the above-described conventional technology. In the case of a copying abnormality, an alarm is reliably generated to prevent machining defects, and the end face of the work is automatically adjusted. It is an object of the present invention to provide a laser processing method and an apparatus for detecting a laser beam and executing a program.

[0007]

According to a first aspect of the present invention, there is provided a laser processing method according to the first aspect of the invention. In the laser processing method to be performed, an upper threshold value which is a voltage value indicating a maximum distance between the sensor and the work and a lower threshold value which is a voltage value indicating a minimum distance are set in advance to perform appropriate copying. An alarm is issued and the processing machine is stopped when the sensor waveform at the time of the copying continuously exceeds the upper threshold value for a predetermined time or falls below the lower threshold value. .

Accordingly, when performing copying using a capacitance type sensor, in order to perform copying while keeping the distance between the work and the sensor within an appropriate range, the voltage value indicating the maximum limit of the distance between the work and the sensor is increased. The threshold value is stored, and the voltage value indicating the minimum distance is stored as the lower threshold value. When the upper threshold value is continuously exceeded for a certain period of time or when the lower threshold value is continuously maintained for a certain period of time. Sometimes, a warning is issued that the distance between the workpiece and the sensor is not appropriate, and the processing machine is stopped.

According to a second aspect of the present invention, there is provided a laser processing method comprising:
In the laser processing method in which the workpiece is machined after performing copying using a capacitance type sensor prior to laser processing, copying is performed in advance on the top surface of the work, the end surface of the work, and a place where there is no work, and each voltage value is stored. In advance, when actual laser processing is started, the laser processing is started assuming that the position detected by the sensor with the stored voltage value indicating the end face of the work is the end face position of the work. It is a feature.

Therefore, when processing is performed, a position where the output of the capacitance type sensor is measured and stored in advance and becomes a voltage value indicating the end surface position of the work is set as the end surface position of the work, and the subsequent processing is performed. I do.

According to a third aspect of the present invention, there is provided a laser processing apparatus comprising:
What is claimed is: 1. A laser processing apparatus for processing a workpiece after performing scanning prior to laser processing, comprising: a capacitance-type sensor for performing the copying; and a maximum of the sensor and the workpiece in advance for performing appropriate copying. Input means for inputting an upper threshold value which is a voltage value indicating the limit distance and a lower threshold value which is a voltage value indicating the minimum distance, and a signal from the sensor at the time of the copying continues to be higher for a predetermined time. A comparison / judgment unit for judging that the value has been exceeded or has fallen below the lower threshold, and that the comparison / judgment unit has continuously exceeded the upper threshold or has fallen below the lower threshold for a predetermined time. An output means for issuing an alarm when the judgment is made, and a command unit for giving a command to stop the processing machine after the alarm is issued are provided.

Therefore, when the copying is performed by the capacitance type sensor, the copying is performed by keeping the distance between the workpiece and the sensor within an appropriate range. Enter the value as the upper threshold value and the voltage value indicating the minimum distance between the workpiece and the sensor as the lower threshold value. When it is determined that the threshold value has been exceeded, or that the value has been below the lower threshold value for a certain period of time, a warning is issued by the output means that the distance between the workpiece and the sensor is not appropriate, and a command unit is issued to stop the processing machine.

According to a fourth aspect of the present invention, there is provided a laser processing apparatus comprising:
A laser processing apparatus for processing a workpiece after performing the scanning prior to the laser processing, a capacitance-type sensor for performing the copying, the upper surface of the work using the sensor in advance, the end face of the work, A memory that stores each voltage value by performing scanning in a place where there is no work, and compares a signal from the sensor with a voltage value indicating an end face of the work stored in the memory when actual laser processing is started. A comparison / judgment unit for judging whether or not to indicate the end face of the work
And a command unit for instructing the position of the sensor when the comparison / judgment unit indicates the end surface of the work to be the end surface position of the work to start laser processing. Things.

Therefore, scanning is performed by a capacitance type sensor prior to laser processing, and scanning is performed in advance on the upper surface of the work, the end surface of the work, and a place where there is no work, and each voltage value is stored in a memory. When the actual laser processing is started, the signal from the sensor is compared with each voltage value stored in the memory by the comparing / determining unit, and the voltage indicating the end face of the work in which the signal from the sensor is stored. When it is determined that the value coincides with the value, the position at this time is regarded as the end surface position of the work, and the laser processing is started according to a command from the command unit.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

The laser beam machine 1 for carrying out the laser beam machining method according to the present invention is an ordinary laser beam machine known in the art, and a detailed description thereof will be omitted.

Referring to FIG. 1, in the state as shown in FIG. 4 described above, copying was performed by setting the gap between the sensor S and the work W to a predetermined amount (here, 1.5 mm). A voltage waveform A from the sensor at the time (solid line in FIG. 1) is shown, and shows a waveform of an appropriate amplitude.

A curve B in FIG. 1 shows a waveform from the sensor S in a state where there is no work W below the sensor S. This shows a case where the distance between the sensor S and the work is too large. Therefore, the amplitude of the voltage waveform is large.

The curve C in FIG.
The sensor waveform at the time of calibration for m is shown, and the case where the distance between the sensor S and the work W is too short is shown, and the amplitude of the voltage waveform is small.

In FIG. 1, straight lines α and β indicate threshold values. The threshold value α is a limit value indicating that the amplitude exceeds the threshold value α, that is, the distance between the sensor S and the workpiece W is too large. On the other hand, if it is less than the threshold value β, the amplitude is too small. That is, it is a limit value indicating that the distance between the sensor S and the work W is too short.

Therefore, if the threshold value α is exceeded or the threshold value β or less is maintained for a predetermined time or more, an alarm is issued and the machine is stopped.

Referring to FIG. 2, the NC unit 7, which is a control unit for controlling the laser beam machine 1 and the like, has a CPU 9 as a central processing unit. The CPU 9 has data input and mode switching. For example, an input unit 11 such as a keyboard for performing various operations, and an output unit 13 such as a CRT or a buzzer for displaying various data or issuing an alarm are provided. Further, a timer 15 is connected to the CPU 9.

A sensor S is connected to the CPU 9 via a controller 17. Also, a memory 19 is connected, and stores data and the like input by the input means 11. Further, the comparison / judgment unit 21 compares the signal from the sensor S with the upper threshold value α and the lower threshold value β stored in the memory 19 to determine whether the signal is over or under. It is determined whether or not the signal from the timer 15 exceeds the upper threshold value α or lower than the lower threshold value β for a predetermined time. The command unit 23 is a comparison / judgment unit 2
The movement of the processing head 3 is instructed based on the result of the determination in step 1.

From the above results, the machine is stopped when the interval between the sensor S and the work W is not appropriate and the normal copying is not performed, so that the machining failure can be prevented.

Next, a laser processing method for the workpiece W set at an arbitrary position on the processing table 5 of the laser processing machine 1 will be described.

The work W is detected in advance by the capacitance sensor S.
The potential of the upper surface of the workpiece W, the potential of the end face of the workpiece W, and the potential of the location where the workpiece W is absent are stored in the controller 17.

Referring to FIG. 3, the work W is set at an arbitrary position on the processing table 5 (step S1), the NC unit 7 is set to the end face detection mode by the input means 11 (step S2), and the start button is pressed. Start (step S3).

The Z-axis is lowered by a command from the command unit 23, the processing head is lowered from the work W until a predetermined gap is reached, and the sensor S detects a potential stored in the controller 17 with respect to the upper surface of the work W. Is stopped (step S4).

The machining head 3 is moved to X by a command from the command unit 23.
(Step S5), and when the sensor S detects the same potential as the potential stored in advance with respect to the end surface position of the work W, the controller 1
7 outputs an output signal to the NC device 7 (step S
6). Upon receiving the output signal from the controller 17, the NC device 7 stores the coordinate value at that time in the memory 19 as an end face position (step S7), and ends the end face detection mode (step S8).

When performing laser processing, the laser processing is first performed after moving to the coordinate position stored as the end face position (step S9), and then the laser processing is started (step S1).
0).

From the above results, the end face position of the work W set at an arbitrary position on the processing table 5 can be detected quickly and accurately, so that high-precision laser processing can be performed efficiently.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes.

[0033]

As described above, in the laser processing method according to the first aspect of the present invention, when performing copying using a capacitance-type sensor, the copying is performed while keeping the distance between the workpiece and the sensor within an appropriate range. Therefore, the voltage value indicating the maximum limit of the distance between the workpiece and the sensor is stored as the upper threshold, the voltage value indicating the minimum distance is stored as the lower threshold, and the upper threshold is maintained for a certain period of time. When the value exceeds the threshold or continuously falls below the lower threshold for a certain period of time, a warning is issued indicating that the distance between the workpiece and the sensor is not appropriate, and the processing machine is stopped, preventing improper copying and avoiding processing defects. can do. Further, it is possible to prevent the sensor from rising upward in the case of a sensor failure and to issue an alarm.

In the laser processing method according to the second aspect of the present invention, when processing is performed, the position where the output of the capacitance type sensor is measured in advance and stored as a voltage value indicating the end surface position of the work is determined. Since subsequent processing is performed as the end face position of the work, accurate processing can be performed even for a work set at an arbitrary position on the processing table.

In the laser processing apparatus according to the third aspect of the present invention, when the copying is performed by the capacitance type sensor, in order to perform the copying while keeping the distance between the workpiece and the sensor within an appropriate range, the workpiece is input to the workpiece by the input means. The voltage value indicating the maximum distance of the sensor is input as the upper threshold and the voltage value indicating the minimum distance between the workpiece and the sensor is input as the lower threshold, and the comparison / judgment unit compares it with the signal from the sensor. If it is determined that the upper threshold has been continuously exceeded for a certain period of time or the lower threshold has been continuously dropped for a certain period of time, a warning is issued by the output means that the distance between the workpiece and the sensor is not appropriate, and a command unit is issued. To stop the processing machine,
Inappropriate copying can be prevented, and processing defects can be avoided. Further, it is possible to prevent the sensor from rising upward in the case of a sensor failure and to issue an alarm.

In the laser processing apparatus according to the fourth aspect of the present invention, scanning is performed by a capacitance-type sensor prior to laser processing, and scanning is performed in advance on the upper surface of the work, the end surface of the work, and a place where there is no work, to thereby control each voltage. The values are stored in the memory, and when the actual laser processing is started, the signal from the sensor is compared with each voltage value stored in the memory by the comparison / determination unit, and the signal from the sensor is stored. When it is determined that the voltage value matches the voltage value indicating the end face of the work, the position at this time is regarded as the end face position of the work, and the laser processing is started according to the command of the command unit. Accurate machining can be performed on the set workpiece.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing threshold values in a laser processing method according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of an NC device.

FIG. 3 is a flowchart showing a laser processing method according to the present invention.

FIG. 4 is a diagram illustrating a state of copying that is more common than in the past.

FIG. 5 is an explanatory diagram illustrating a state in which a sensor detects an end surface of a work.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser processing machine (processing machine) 11 Input means 13 Output means (alarm) 19 Memory 21 Comparison / judgment part 23 Command part S Sensor W Work α Upper threshold β Lower threshold

Claims (4)

[Claims] 1. A laser processing method for processing a workpiece after performing scanning with a capacitance type sensor prior to laser processing, and indicates a maximum distance between the sensor and the workpiece in advance so as to perform appropriate copying. An upper threshold value which is a voltage value and a lower threshold value which is a voltage value indicating a minimum distance are set in advance, and the sensor waveform at the time of the above-mentioned scanning continuously exceeds the upper threshold value for a predetermined time or is lower than the lower threshold value. A laser processing method, wherein an alarm is issued and the processing machine is stopped when the value falls below a threshold value. 2. A laser processing method for processing a workpiece after performing scanning using a capacitance type sensor prior to laser processing. In the laser processing method, the upper surface of the workpiece, the end face of the workpiece, and a location where no workpiece is present are copied in advance. Each voltage value is stored, and when actual laser processing is started, laser processing is performed on the assumption that the stored voltage value indicating the end face of the work is detected by the sensor as the end face position of the work. Starting, a laser processing method. 3. A laser processing apparatus for processing a workpiece after performing copying before performing laser processing, wherein the sensor is a capacitance type sensor for performing the copying and the sensor is configured to perform appropriate copying in advance. Input means for inputting an upper threshold value which is a voltage value indicating the maximum distance between the workpiece and the workpiece, and a lower threshold value which is a voltage value indicating the minimum distance, and a signal from the sensor during the copying continues for a predetermined time. A comparison / judgment unit for judging that the threshold value has been exceeded or has fallen below the lower threshold value, and that the comparison / judgment unit has continuously exceeded or decreased the upper threshold value for a predetermined time. A laser processing apparatus, comprising: output means for issuing an alarm when it is determined that the threshold value has fallen below; and a command unit for giving a command to stop the processing machine after issuing the alarm. 4. A laser processing apparatus for processing a workpiece after performing scanning prior to laser processing, comprising: a capacitance type sensor for performing the scanning; and an upper surface of the workpiece using the sensor. The end face of the work, the memory that stores each voltage value by performing scanning on a place where there is no work, and the end face of the work that is stored in the memory when the signal from the sensor is stored when actual laser processing is started. A comparison / judgment unit for judging whether or not the end face of the work is indicated by comparing with the indicated voltage value; and a position of the sensor when the comparison / judgment unit judges that the end face of the work is indicated. And a command section for commanding to start laser processing.