JPH02179375A - Laser beam machining method - Google Patents

Abstract

PURPOSE:To continue machining without bringing a nozzle into contact with a work even if the work is partly cut off by executing gap control to clamp the position of the nozzle from just before the end point of a machining passage up to the end point during the execution of an NC command. CONSTITUTION:The work 46 is irradiated with laser light for machining from a nozzle 45 by which the cutting of the work is executed. The gap between the tip of the nozzle and the work is measured by a distance detector 43 and is fed back to a processor 11 while the NC command is executed. The processor 11 interrupts this profiling control just before the end point of the machining passage. The position of the nozzle 45 is thereafter clamped in the position at the point of the time when the control is interrupted. The cutting is executed up to the end point. The casual fluctuation in the position of the nozzle 45 is obviated even if the burring or cutting off of a cut off part 52 is executed. The continuation of the machining is possible in this way and the machining efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser processing method for cutting a workpiece according to processing steps, and particularly to a laser processing method that improves the problem of gap control between a nozzle and a workpiece.

[Conventional technology]

By combining the high-speed processing of a laser processing machine with the features of a numerical control system (CNC) that can control complex contours, it is now possible to cut even complex-shaped machining paths at high speed without contact. It's coming. In actual cutting, tracing control and the like are performed while executing NC commands so that the machining conditions do not change due to warpage of the workpiece or the like.

This allows cutting to be performed while keeping the gap between the nozzle and the workpiece constant.

Fig. 2 shows an example of processing. In the figure, 51 is a processing passage;
B1 and B2 start cutting of the workpiece 46 from 0 point P1 indicating the beam spot of the probe laser beam for gap measurement, and cut the workpiece 46 along the processing path 51 passing through point P2 and returning to point P1. Execute.

[Problem to be solved by the invention]

By the way, as the machining progresses, the cut-off portion 52 begins to warp in the vicinity of returning to point P1, and when the machining is finished, the cut-off portion 5
2 is cut off. At this time, the reflected light of beam spot B1 is reduced by half. Therefore, the measured value of the gap changes suddenly, and it is judged as if the gap itself suddenly changed. As a result, the nozzle follows the cut-off portion 52 and collides with the remaining portion 53, resulting in loss of control.

The present invention has been made in view of these points, and it is an object of the present invention to provide a laser processing method that improves the problem of gap control between a nozzle and a workpiece.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a laser processing method in which a laser beam is irradiated onto the surface of a workpiece from a nozzle part of a laser processing device, and the workpiece is cut according to a processing process, in which a gap between the nozzle part and the workpiece is A distance detector is provided to measure and output a distance signal, and the distance signal is fed back to a position control circuit to start cutting from the starting point of the processing path while controlling the gap to keep the gap constant; When a predetermined point set near the end point of the machining path is reached, the gap control is interrupted, the nozzle part is clamped at the position at the time point, and the cutting process is continued until the end point. A featured laser processing method is provided.

(Operation) Gap control keeps the distance between the nozzle and the workpiece constant and starts cutting from the starting point of the machining path. Gap control is interrupted when the cutting process is executed just before the end point of the machining path, and at the same time The nozzle part is clamped at this position, and then the nozzle part or the workpiece is moved in the clamped state to perform cutting until the end point of the machining path.This allows the nozzle part to be cut off when the workpiece is cut off at the end point. This prevents problems such as chasing a workpiece and colliding with other workpieces.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a cutting laser device for carrying out the present invention. In FIG. 0, a numerical control device (CNC) 10 stores and executes NC commands and performs tracing control.

The processor 11 controls the overall operation of the numerical control device 10. The memory 12 stores a control program. The display control circuit 14 creates and sends display data. The distance detection circuit 15 receives a distance signal from a distance detector (described later), converts it into a digital value, and inputs the digital value to the processor 11. The processor calculates a deviation from the reference distance from this distance data, and calculates a speed command proportional to this deviation. A speed command from the processor 11 is converted into an analog value by a D/A converter 16, amplified by a servo amplifier 17, and output to a servo motor to be described later. The position detection circuit 18 receives a position signal from a position detector attached to a servo motor, converts it into a digital value, and inputs it to the processor 11.

The display device 30 is a CRT or a liquid crystal display device, and receives video signals from the display control circuit 14 to perform various displays.

The servo motor 42 is a servo motor that drives the tracing axis, and the position of the tracing axis is detected by the position detector 4I. The distance detector 43 measures the gap between the nozzle 45 and the workpiece 46 and outputs a distance signal to the distance detection circuit 15. As the distance detector 43, a laser measuring device using a semiconductor laser is used. Reference numeral 44 indicates a probe laser beam for measurement. Note that in addition to this, a distance detector such as a capacitive sensor or a magnetic sensor can be used. A workpiece 46 is fixed on a machine table 47.

The workpiece 46 is irradiated with a processing laser beam (not shown) from the nozzle 45, and the workpiece 46 is cut. In FIG. 1, only the servo system for the tracing axis is shown, and the servo systems for the other axes are omitted.

Here, while executing the NC command, the distance detector 4
3, the gap from the tip of the nozzle 45 to the workpiece 46 is measured and fed back to the processor 11. As a result, the tip of the nozzle 45 is basically controlled to maintain a constant distance from the workpiece 46 by tracing control while executing the NC command.

The processor 11 interrupts this profiling control just before the end point of the machining path. It is preferable that the point of interruption be at a point where the workpiece does not warp and is as close to the end point as possible. In this embodiment, the point of interruption is set to the point when the distance to the end point reaches 1 mm.

After this, the position of the nozzle 45 is clamped to the position at the time when the profile control was interrupted, and the cutting process is executed to the end point.

Therefore, even if the cut-off portion 52 shown in FIG. 2 is warped or cut off, the position of the nozzle 45 will not change inadvertently.

In addition, in the next process of cutting, tracing control is started again from the starting point.

Further, the setting value at the time when the above-described tracing control is interrupted is selected depending on the type of machining, the material of the workpiece, etc.

〔Effect of the invention〕

As explained above, in the present invention, gap control is performed during the execution of the NC command, and on the other hand, the nozzle position is clamped from just before the end point to the end point of the processing path, so even if a part of the workpiece is cut off, the nozzle without contacting the workpiece,
Machining can be continued, improving machining efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a cutting laser device for implementing the present invention, and FIG. 2 is a conceptual diagram showing an example of a processing example. 1 Processor 2・・・−−−−−−−−−−−Memory 5・・・・−
・・・−・・−Distance detection circuit 8・−・−・−・−
・Position detection circuit 1--Position detector 2------1...--m--Servo motor 3
--- Distance detector 4 --- Probe laser beam 5 Nozzle 6 --- Workpiece --- Machining path 2 ---
−・−・−・−Inner work 3 −・−・・−・−・・・
・・Outer workpiece 1 −・・・・Start point and end point 2 of processing path ・Beam spot patent applicant FANUC Co., Ltd. agent Patent attorney Takeshi Hattori 10・・・・・・・・・−・・Numerical control device diagram 2

Claims (5)

[Claims] (1) In a laser processing method in which a laser beam is irradiated onto the surface of a workpiece from a nozzle part of a laser processing device and the workpiece is cut according to a processing process, the gap between the nozzle part and the workpiece is measured and a distance signal is output. A distance detector is provided to feed back the distance signal to a position control circuit to start cutting from the start point of the machining path while controlling the gap to keep the gap constant, and to cut near the end point of the machining path. A laser processing method characterized in that the gap control is interrupted when a set predetermined point is reached, the nozzle part is clamped at the position at the time, and cutting is continued until the end point. (2) The laser processing method according to claim 1, wherein the processing path is a closed path in which the coordinates of the starting point and the coordinates of the ending point match each other. (3) When the machining process is composed of a plurality of mutually independent machining paths, the gap control is restarted from the starting point of each machining path. Laser processing method. (4) The laser processing method according to claim 1, wherein the gap control is performed by profile control. (5) The laser processing method according to claim 1, wherein the distance detector is a laser distance measuring device.