JPS629794A - Laser beam machining control device - Google Patents

Abstract

PURPOSE:To prevent the burn through of the body to be worked by reducing a working speed corresponding to the angle variation in the working direction and by adjusting automatically the laser output according to the working speed as well. CONSTITUTION:An NC device 10 drives driving motor 8, 9 according to the working program and moves the body 6 to be worked. An output control device 11 emits from an oscillator 1 the laser beam 2 conformed to the working conditions. The control device 11 calculates the angle variation in working direction and compares it with the set angle as well. In this case, the device 11 changes the programmed work speed to lower speed in case of the changed angle being a smaller acute angle than the set angle. The output of the laser beam 2 is varied further according to the change in the work speed thereof. Due to the output of the laser beam 2 being automatically adjusted as well as the reduction in the work speed the local overheat is prevented and the burn through is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser processing control device that performs processing without melt drop.

[Conventional technology]

FIG. 4 is a schematic diagram of a conventional laser processing device.

In Figure 4, (1) is a laser oscillator, (2) is a laser beam output from the laser oscillator (1), and (3) is a reflector (4) and lens for condensing the laser beam (2). (
5), etc., (6) is a workpiece to be irradiated with the laser beam focused by the optical means (3), and (7)
) is the processing table on which the workpiece (6) is placed, (8)
(9) is a motor that drives the processing table (7) to move the workpiece (6) in the X-axis direction of the XY plane perpendicular to the laser beam (2) irradiated onto the workpiece (6); Drive the processing table (7) in the Y-axis direction of the XY plane to cut the workpiece (
(10) is a drive motor that moves the workpiece (6);
NG (numerical control) to process the workpiece (6) by executing a machining program in which the machining speed of ), the machining direction of the workpiece (6), and the sending of laser light to the workpiece (6) are programmed. The device, (11) is the workpiece (6)
This is an output control circuit that performs on/off control (output control) of the laser beam (2) output from the laser oscillator (1) according to the material and thickness of the laser beam (1).

Next, the operation of the conventional laser processing control device will be explained. First, the NC device (1o) follows the machining program.
Drive the drive motors (81, (91) to move the workpiece (6) at a programmed machining speed in a programmed machining direction, and control the control circuit (11),
The workpiece (6
) A laser beam (2) with an output corresponding to the material, thickness, etc. of the workpiece (6) is sent out from the laser oscillator (1) according to the position of the workpiece (6) to process the workpiece (6).

[Problem that the invention seeks to solve]

By the way, conventional laser processing control devices control the output of the laser beam (2) and the processing of the workpiece (6), regardless of the processing shape, for workpieces of the same material and thickness. The speed was constant. Therefore, when laser processing is performed so that the processed shape becomes an acute angle as shown in FIG. 5, the first processed part (6a) and the second processed part (6b) are located close to each other. Therefore, the later processed part (6b)
There was a problem that there was no place for heat to escape, causing local overheating and melting.

The present invention has been made to solve the above problems,
The object of the present invention is to provide a laser processing control device that does not cause dropouts.

[Means for solving problems]

Therefore, the present invention provides a machining program in which at least the machining speed of the workpiece, the machining direction of the workpiece, and the sending of laser light to the workpiece are programmed, and processing and detection for detecting the machining direction of the workpiece from this machining program. A process for detecting whether there is a change in the machining direction, a process for calculating the change angle between the machining direction before the change and the machining direction after the change, when there is a change in the machining direction, and the calculated change angle and the preset settings. If the change angle is smaller than the set angle, the programmed machining speed is changed to a speed slower than this machining speed until the machining direction is changed beyond a preset distance from the position where the machining direction is changed. a control device that executes the speed control program at least before execution of the machining program; a laser oscillator; and an optical means that irradiates the workpiece with laser light output from the laser oscillator. , a driving means for moving the workpiece two-dimensionally at a programmed processing speed or a changed processing speed with respect to the laser beam sent out according to the processing program; and a drive means for calculating the processing speed of the workpiece and the calculated processing speed. a first voltage-frequency conversion circuit that outputs a pulse signal with a frequency corresponding to the output voltage of the speed calculation circuit; Accordingly, the irradiation time of the laser beam to the workpiece is set, and the pulse width adjuster outputs a voltage corresponding to the set irradiation time, and the pulse width adjuster outputs a voltage corresponding to the output voltage of the pulse width adjuster. The second voltage-frequency conversion circuit that outputs a pulse signal and the pulse signal output from the first voltage-frequency conversion circuit create a Heylepel state, and the signal output from the second voltage-frequency conversion circuit causes a low level state. A laser processing control device is constituted by a flip-flop that outputs a signal indicating a state, and a laser light control circuit that turns off and on the laser light output from a laser oscillator based on the output signal of the flip-flop.

[Effect]

In the laser machining control device configured as described above, the control device executes the speed control program before executing the machining program, and when the machining shape has an acute angle, changes the programmed machining speed to a slower speed. A laser oscillator irradiates a workpiece with laser light via optical means according to a processing program. A drive means moves the workpiece in a programmed machining direction at a programmed machining speed or a modified machining speed. At this time, the speed calculation circuit outputs a voltage having a magnitude corresponding to the machining speed of the workpiece, and the first voltage-frequency conversion circuit outputs a pulse signal having a frequency corresponding to this output voltage. On the other hand, the pulse width adjuster outputs a voltage corresponding to the irradiation time of the laser beam onto the workpiece, and the second
The voltage-frequency conversion circuit outputs a pulse signal with a frequency corresponding to this output voltage. Further, the flip-flop outputs a signal that becomes high level by the pulse signal of the first voltage-frequency conversion circuit and becomes low level by the pulse signal of the second voltage-frequency conversion circuit, and the laser light control circuit Based on this signal, on/off control of the laser light output from the laser oscillator is performed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a laser processing control device according to the present invention. In addition, (1) to (9) in Fig. 1 correspond to (1) to (9) in Fig. 4.
This part corresponds to 1) to (9), and the explanation thereof will be omitted. (10) is a conventional NC device in which at least the processing speed of the workpiece (6), the processing direction of the workpiece (6), and the sending of the laser beam (2) to the workpiece (6) are programmed. and a speed fllJ# program for moving the workpiece (6) at a machining speed slower than the programmed machining speed when the machining shape is an acute angle. Further, (11) is an output control circuit that controls the output of the laser beam (2) in response to the NC device (10) controlling the processing speed of the workpiece (6), and (12) is a drive motor. (8) a tacho generator that detects the rotation speed;
(13) is a tachometer generator that detects the rotation speed of the drive motor (9), and (15) is a tachometer generator (12).

(13), a speed calculation circuit consisting of a multiplier circuit (1B), (17) and a square root circuit (18); (19) outputs a pulse signal with a frequency corresponding to the output voltage of the speed calculation circuit (15); The first voltage/frequency conversion circuit (hereinafter referred to as V7F conversion circuit), (20) is connected to the workpiece (6
) is a variable resistor (pulse adjuster) that sets the pulse width of the laser beam (2) that is irradiated to the laser beam (21). (
(20) is a second V/F conversion circuit that outputs a pulse signal with a frequency corresponding to the output voltage of (22), a set-reset flip-flop (hereinafter referred to as R8-FF);
3) is a laser light control circuit.

The multiplier circuit (16) squares the voltage signal Vx, which has a magnitude corresponding to the speed in the x-axis direction of the stage (7) (workpiece (6)) detected by the tacho generator (12), to obtain a voltage signal v2χ. Output. Similarly, the multiplication circuit (17) outputs the Y of the stage (7) detected by the tacho generator (13).
The voltage signal Vy having a magnitude corresponding to the axial velocity is squared to output a voltage signal V″y. Square root cycle #(18) is a voltage signal that is the square root of the sum of the voltage signals V″X and v2y. Output V f (=V'x+V'y). Therefore, this voltage signal Vf corresponds to the actual machining speed of the workpiece (6).

The first V/F conversion circuit (19) outputs a pulse signal Sf with a frequency Ff corresponding to the voltage signal Vf output by the square root circuit (18).

By the way, as mentioned above, when the workpiece (6) has an acute angle, the NC device (
11). If the output of the laser beam (2) does not change when the processing speed slows down, more energy of the laser beam (2) will be poured into the workpiece (6), causing melt drop. Therefore, in the present invention, the workpiece (6) is intermittently irradiated with the laser beam (2) in accordance with the processing speed of the workpiece (6). The beam diameter of the laser beam (2) is φ [Kaku], and the processing speed of the workpiece (6) is V [
m/see], the period Tf [seconds] of the laser beam (2) to be applied to the workpiece (6) is Tfiso2V/φ
become. In other words, if the workpiece (6) moves approximately half the beam diameter of the laser beam (2) (φ/2 [:mm]) during the period Tf (seconds) of the laser beam (2), then Even if the workpiece (6) is intermittently irradiated with the laser beam (2), the workpiece (6) will be processed continuously and without melt drop. Therefore, the workpiece (6
), the frequency of the pulse signal Sf is Ff (Hzl(period Tf (seconds)
). The variable resistor (20) is connected to the workpiece (
It is determined by the material and thickness of 6), and adjusts the irradiation time per pulse of the laser light (2) that is intermittently irradiated as described above.

The V/F conversion circuit (21) is a variable resistor! (20) A pulse signal S having a frequency Ft corresponding to the output voltage Vt
Convert to t. Note that the pulse signal St is
It is outputted after a certain period of time has elapsed since the pulse signal St is output, that is, after the irradiation time per pulse of laser beam (2) has elapsed, and it is not output when the frequency Ft of the pulse signal St exceeds a certain frequency.

, RS -F F (22) has a pulse signal Sf of the V/F conversion circuit (19) inputted to the set terminal (S), so that the output signal Vp becomes a high level "L" state, and the reset terminal (R) By the pulse signal St of the V/F conversion circuit (21) input to the output signal Vp low level “H”
The state will be as follows. The laser light control circuit (23) controls the pulse conditions of the laser light (2) according to the signal Vp. In this way, the output control circuit (11) reduces the output of the laser beam (2) when the processing speed of the workpiece (6) is slow, and reduces the output of the laser beam (2) when the processing speed of the workpiece (6) is fast. Increase the output of light (2).

Next, the overall operation of the laser processing control device according to the present invention will be explained with reference to FIGS. 2 and 3. FIG. 2 is a flowchart of the speed control program, and FIG. 3 is a timing chart of the processing speed and the output of the laser beam (2). First, the NC device (11) detects the machining direction (Step 101), and determines whether or not there is a change in the machining direction. If there is no change in the machining direction, the process proceeds to Step 106 (Step 1).
02).

When there is a change in the machining direction, the NC device (11) calculates the change angle, which is the angle between the machining direction before the change and the machining direction after the change (step 103), and compares the detected change angle with the preset setting. If the changed angle is larger than the set angle, proceed to step 106 (step 1
04). When the change angle is smaller than or equal to the set angle, the NC device (11) changes the programmed machining speed to a set speed that is slower than the machining speed (step 105).
).

Next, the NC device (11) drives the drive motor (81, [9)
The control circuit (11) is driven to move the workpiece (6) in the programmed machining direction at the programmed machining speed or the changed machining speed. ) to irradiate the workpiece (6) with the laser beam (2) whose output is controlled by the laser beam (2) to process the workpiece (step 106). In this case, when there is a change in the machining direction, the workpiece (6) moves at the programmed machining speed until it reaches point a, as shown in Figure 3(a), and from point a, the machining direction is changed to point b. From point b to point 0, it moves at a speed slower than the programmed machining speed for the set distance, and from point 0, it moves at the programmed machining speed again. You will have to move. Also, in response to changes in machining speed, Fig. 3 (b)
), the output of the laser beam (2) changes.

The NC device (11) determines whether or not the machining of the section in which the machining direction has been detected has been completed, and when the machining has been completed, the process proceeds to step 112 (step 1o7).

If the machining has not been completed, it is determined whether the machining speed has been programmed or changed, and if the machining speed is the programmed machining speed, the process proceeds to step 106 (step 108). If the machining speed has been changed, the machining distance from the position where the machining direction was changed to the current machining position is detected in step 10.
9) Compare the detected machining distance and the preset setting distance, and if the machining distance is smaller than the set distance, proceed to step 1.
The process proceeds to step 06 (step 110), and if the machining distance is greater than the set distance, the process changes the machining speed to the programmed machining speed (step 111), and then proceeds to step 106. Note that steps 107 to 111 are not executed after the machining (step 106) is finished, but are performed at appropriate intervals during the machining.

When the machining of the section in which the machining direction has been detected is completed, the NC device (11) determines whether all machining has been completed, and if all machining has not been completed, the process proceeds to step 101, and continues until all machining is completed. , steps 101 to 112 are repeatedly executed.

〔Effect of the invention〕

As explained above, according to the present invention, before executing the machining program and machining the workpiece, if the change angle between the machining direction before the change and the machining direction after the change is smaller than the set angle, the machining The programmed machining speed is changed to a speed slower than this machining speed until the set distance is exceeded from the position where the direction is changed, and the machining speed of the workpiece is moved at the programmed machining speed or the changed machining speed. By detecting this and changing the output of the laser beam according to the detected processing speed, melt drop does not occur even if the processed shape of the workpiece is at an acute angle.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a laser processing control device according to the present invention, Fig. 2 is a flowchart of a speed control program, Fig. 3 is a timing chart of processing speed and laser beam output, and Fig. 4 is a conventional laser processing control. FIG. 5, which is a schematic diagram of the apparatus, is an explanatory diagram of the processed shape of the workpiece. In each figure, 1 is a laser oscillation field, 2 is a laser beam, 3 is an optical means, 4 is a reflecting mirror, 5 is a lens, 6 is a workpiece, 7 is a processing table, 8 and 9 are drive motors, 10 is an NC device, 11
is the output control device, 12.13 is the tacho generator, 15
is a control circuit, 16.17 is a multiplication circuit, 18 is a square root circuit, 19 and 21 are V/F conversion circuits, 20 is a variable resistor, 2
2 is a set/reset flip-flop, and 23 is a laser light control circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Patent Attorney Masaru Sato Procedural Amendment (Voluntary) May 28, 1986

Claims (1)

[Claims] A machining program in which at least a machining speed of a workpiece, a machining direction of the workpiece, and a laser beam transmission to the workpiece are programmed; and a process of detecting the machining direction of the workpiece from the machining program; A process for detecting whether or not there is a change in the machining direction, a process for calculating a change angle between the machining direction before the change and a machining direction after the change when the machining direction has changed, and a process for calculating the change angle made between the machining direction before the change and the machining direction after the change, and a process that is based on the calculated change angle and the preset value. If the calculated change angle is smaller than the set angle, the programmed machining speed will be lower than the machining speed until it exceeds a preset distance from the position where the machining direction is to be changed. a control device that includes a speed control program including a process of changing the processing speed to a slower speed and executes the speed control program before executing the processing program; a laser oscillator; an optical means for irradiating the workpiece; a driving means for moving the workpiece two-dimensionally at the programmed machining speed or the changed machining speed with respect to the laser beam sent out according to the machining program; A speed calculation circuit that calculates the processing speed of the workpiece and outputs a voltage of a magnitude corresponding to the calculated processing speed, and a first voltage that outputs a pulse signal of a frequency corresponding to the output voltage of the speed calculation circuit. - Setting the irradiation time of the laser beam to the workpiece according to the frequency conversion circuit and the material and thickness of the workpiece, and outputting a voltage corresponding to the set irradiation time. a pulse width regulator; and a second pulse width regulator that outputs a pulse signal having a frequency corresponding to the output voltage of the pulse width regulator.
A signal that becomes a high level state due to a pulse signal outputted by the voltage-frequency conversion circuit and the first voltage-frequency conversion circuit, and becomes a low level state due to a pulse signal outputted from the second voltage-frequency conversion circuit. 1. A laser processing control device comprising: a flip-flop that outputs an output signal; and a laser light control circuit that controls on/off a laser light output from the laser oscillator based on an output signal of the flip-flop.