JPS629792A - Method for controlling on/off of laser beam in laser beam machine - Google Patents

Abstract

PURPOSE:To uniform a working by detecting the movement accelerating period of a laser beam and by starting the outgoing of the laser beam simultaneously with the time when the moving speed reaches a constant rate. CONSTITUTION:An F-V convertor 2, differentiation circuit 3, waveform shaping circuit 4 are respectively arranged in series corresponding to a position encoder 1. The position encoder 1 arranged on a laser beam moving mechanism inputs to the F-V convertor 2 the pulse in the frequency in proportion to the moving speed. Such a digital signal as becoming a logic '1' while the movement accelerating period is obtd. when the voltage signal proportionate to the frequency of the convertor 2 is inputted to the differentiation circuit 3 and inputted further to the waveform shaping circuit 4. The emission of the laser beam is started simultaneously with the fall or rise of this signal, namely simultaneously with the time when the moving speed reaches a constant rate. The energy of the laser beam thus becomes constant and the work is unified.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for controlling ON-OFF of a laser beam in a laser processing machine having a mechanism that allows the laser beam and the workpiece to move relative to each other. In particular, the present invention relates to a method of controlling laser beam emission timing at the start of processing.

(Prior art) Conventionally, laser processing machines with a mechanism that allows the laser beam and the workpiece to move relative to each other have a structure in which the laser beam is emitted and processing begins at the same time as the laser beam begins to move. .

(Problems to be Solved by the Invention) In the conventional configuration described above, it takes a certain amount of time to reach a constant speed after starting the movement. When processing with During the acceleration period until the speed reaches a constant speed, the energy of the laser beam applied to the workpiece is not constant, so a uniform machining trajectory cannot be obtained. There is also a method of synchronizing the repetition of the Q switch with the encoder pulse of the position of the moving mechanism.
In this method, the overlap of laser pulses is constant regardless of the speed, but since the repetition of the Q switch changes in proportion to the speed, the peak output of the laser pulse usually also changes, so the machining trajectory remains unchanged. The disadvantage is that it is not uniform.

(Means for Solving the Problems) In order to solve the above-mentioned drawbacks, it is sufficient to emit the laser beam after the moving speed reaches a constant speed. Therefore, the laser beam on/off control method of the present invention The acceleration period during the movement of the laser beam with respect to the workpiece is detected, and the laser beam is synchronously emitted when the movement speed reaches a constant speed.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a laser beam control device according to an embodiment of the present invention, and FIG. 2 is a diagram showing output waveforms at each part of the block shown in FIG. 1.

In the figure, reference numeral 1 denotes a position encoder provided in the moving mechanism, which outputs a pulse signal as shown in (a) of FIG. 2 in accordance with the moving distance. The repetition frequency of this pulse changes in proportion to the moving speed. This pulse is F-V in Figure 1.
It is input to the converter 2, and a voltage signal proportional to the frequency as shown in FIG. 2 (b) Yc is obtained. This 1-pressure signal is input to the differentiating circuit 3I/c, and is further input to the waveform shaping circuit 4vc to obtain a digital signal (FIG. 2(C)) which becomes logic "1" during the acceleration period during movement. A laser beam as shown in FIG. 2(d) is emitted in synchronization with the falling edge of the digital signal (in the case of positive logic) with VC. In addition,
In the case of negative logic, it is synchronized with the rising edge of the digital signal.

Since there is a delay from when the laser beam starts moving until it is emitted, the movement is started from before the processing start point in anticipation of this delay.

(Effects of the Invention) As explained above, according to the present invention, by detecting the acceleration period during the movement of the laser beam, the emission of the laser beam is started when the movement speed reaches a constant speed, thereby emitting the laser beam uniformly. Can be processed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a laser beam control device according to an embodiment of the present invention, and FIG. 2 is a diagram showing output signal waveforms at each part of the block shown in FIG. 1. 1... Position encoder, 2... F-V converter, 3... Differential circuit, 4... Waveform shaping circuit.

Claims (1)

[Claims] In a laser beam control method for a laser processing machine having a mechanism capable of mutually moving a laser beam and a workpiece, an acceleration period during movement of the laser beam with respect to the workpiece is detected, and the movement speed reaches a constant speed. 1. A method for controlling on/off of a laser beam, characterized in that the emission of the laser beam is started in synchronization with the time when the laser beam is emitted.