JPH0417991A - Device for centering nozzle of laser beam machine - Google Patents

Abstract

PURPOSE:To automatically perform centering by detecting spatters at work with a spatter detecting means and adjusting and moving a nozzle through a nozzle moving means so that splash of the splatters is homogenized by an adjustment controlling means to the center line of the laser beam. CONSTITUTION:As nozzle holder 3, 4 are moved by the rotation and drive of motors M, M respectively in the direction Y, X and both motors are adjusted and driven by an adjustable amount, the nozzle 5 is adjusted and operated by an adjustable amount of the surfaces X, Y. A beam receiving part 9 for condensing the beam is provided at the lower end of each optical fiber 8 to properly detect the optical amount of the spatters from a work at a focal position of the laser beam LB. The spatter beam is detected properly through the optical fiber 8. Each motor M, M is driven in accordance with a compared result of a comparison device.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a nozzle centering device for a laser processing machine.

(Prior Art) In a laser processing machine, in order to perform good laser processing, it is necessary to align the center of a nozzle that irradiates a laser beam on the center line of the laser beam.

Generally, if the center of the nozzle is misaligned with respect to the center line of the laser beam, a lot of spatter may be scattered in the direction opposite to the direction in which the nozzle is misaligned during piercing due to the injection of assist gas. Are known. That is,
Since more assist gas is injected from the side where the nozzle is offset from the center of the piercing process, more spatter is scattered in the opposite direction.

In this way, when the nozzle center is deviated from the center line of the laser beam, the laser processing becomes non-uniform and the processing quality becomes poor.

Therefore, conventionally, a nozzle centering operation was performed by carrying out piercing processing, visually observing the direction of spatter at that time, and manually aligning the nozzle center with the center line of the laser beam.

This manual nozzle centering work involves looking at the spatter scattering direction and operating an adjustment bolt to adjust and move the nozzle in the direction where more spatter is produced.

Specifically, the test piece was brought under the machining head in an unclamped state, the bolts were adjusted while visually observing the spatter scattering direction, the test piece was moved again, the piercing was performed, and the bolt adjustment was repeated. Ta.

(Problem to be solved by the invention) However, in the conventional manual nozzle centering work as described above, the operator has to approach the processing head, which is dangerous, and requires a lot of adjustment due to errors and errors. There have been problems with adjustment accuracy that it takes time and the adjustment results depend on the skill of the operator.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a nozzle centering device for a laser processing machine that can automatically center a nozzle.

[Structure of the invention]

(Means for Solving the Problems) The present invention solves the above problems in a nozzle centering device of a laser processing machine that performs laser processing on a workpiece by irradiating a laser beam from a nozzle provided in a laser processing head. , a nozzle moving means is provided for the processing head to move the nozzle in a plane orthogonal to the irradiation direction of the laser beam, and spatter detection detects the amount of spatter scattered from the workpiece at a plurality of outer peripheral positions of the nozzle. The present invention is characterized by further comprising: adjustment control means for adjusting and moving the nozzle via the nozzle moving means so that the spatter detected by the spatter detection means becomes homogeneous with respect to the center line of the laser beam. .

(Function) Since the nozzle centering device of the laser processing machine of the present invention has the above configuration, the spatter detection means detects spatter during processing, and the adjustment control means makes the spatter scattered uniformly with respect to the center line of the laser beam. The nozzle is adjusted and moved via the nozzle moving means so that the centering is automatically performed.

This automatic centering can of course be performed during a trial piercing process, but also during actual piercing process.

(Example) FIG. 1(a) is a longitudinal cross-sectional view of a laser processing head implementing the present invention, FIG. 1(b) is a vertical cross-sectional view in a direction perpendicular to FIG. 1(a), and FIG. FIG. 2 is a system configuration diagram of a nozzle centering device shown in a bottom view of the laser processing head with an adjustment control device connected thereto.

In FIGS. 1(a) and 1(b), an unfocused laser beam LB output from a laser oscillator (not shown) is input into the center of a cylindrical laser processing head 1. The laser beam LB is focused by a condensing lens 2 provided at the center position of the head, and is focused on a workpiece W.
It is designed to be irradiated by Assist gas AG is introduced from the side of the main body of the processing head 1.

On the other hand, the laser processing head 1 of this example is provided with a nozzle holder 3 that is movable in one direction Y on a plane perpendicular to the irradiation direction of the laser beam LB with respect to the main body of the processing head 1. Further, a nozzle holder 4 is provided with respect to this nozzle holder 3 and is movable in a direction X perpendicular to the direction Y, and a nozzle 5 is fixedly provided on the lower surface of this nozzle holder 4. The center of each nozzle holder 3.4 is hollow, and the laser beam LB is guided through this hollow into a relatively small hole formed at the tip of the nozzle 5.

The main body portion of the processing head 1 includes the nozzle holder 3.
A small motor M is provided which rotates a screw 6 screwed into a nut provided on the side of the nozzle holder 3 to move the nozzle holder 3 in the Y direction.

Further, the nozzle holder 3 is provided with a small motor Mx that rotates a screw 7 that is screwed into a nut provided on the side of the nozzle holder 4 to move the nozzle holder 4 in the X direction. ing.

Therefore, in the processing head 1 of this example, the motors MY, M
By rotating x, the nozzle holders 3 and 4 are moved to Y.
, in the X direction, and by adjusting and driving both motors by an appropriate amount, it is possible to adjust the nozzle 5 by an appropriate amount on the planes X and Y. The maximum operating range of each nozzle holder 3, 4 is, for example, 3
It is about 5 mm. It may be more than this. A minimum movement unit of about 0.1 to 0.2 mm is sufficient.

Therefore, the motors MX and MY do not necessarily need to be servo motors.

Furthermore, four optical fibers 8 are provided on the side of the main body of the processing head 1, which are arranged symmetrically with respect to the center line of the laser beam LB and which face the workpiece W from the lower end of the head. At the lower end of each optical fiber 8, the laser beam LB
In order to properly detect the amount of sputtered light scattered from the work W at the focal position of
, 9C.

9D) is provided. The light receiving section 9 of this example is made of a glass member having a diameter larger than the diameter of the optical fiber 8.
The tip thereof is arranged so as to slightly protrude from the lower end of the processing head 1.

Therefore, the sputtered light collected by each light receiving section 9 is properly detected via the optical fiber 8.

As shown in FIG. 2, the adjustment control device inputs the sputtered light focused by the light focusing section 9 via the optical fiber 8,
A photoelectric conversion device 10 (
IOA, IOB, IOC, 10D), a comparison device 11 that inputs and compares the voltage signals output by these photoelectric conversion devices 10, and a comparison device 11 that inputs and compares the voltage signals output by these photoelectric conversion devices 10, and
X, M.

It is configured to include a distribution device 13 that distributes a drive signal to drivers 12X and 12Y that drive the.

FIGS. 3 and 4 show the comparison device 11 and the distribution device 13.
We have shown the details of the processing performed by .

FIG. 3 is a flowchart showing centering processing for piercing. It is assumed that the piercing process here is a test process for centering.

First, in the initial stage, the workpiece W is clamped by a workpiece clamping device (not shown) driven by an NC device, and a program for controlling the operation is installed in the NC device.

In step 301, piercing is performed.

That is, in FIG. 1, a laser beam LB is output, and a fixed work W is irradiated with the focused laser beam LB, thereby making a hole in the work W. At this time, spatter is scattered from the upper surface of the workpiece W.

Therefore, in step 302, the sputtered light at each position focused by each condenser 9 is converted into a voltage by the photoelectric conversion device 10, and this detected value is input to the comparison device 11.

In step 303, the comparison device 11 compares the detected values input from the photoelectric conversion device 10.

The comparison process here is for each detected value I,, IB.

It compares whether Ic and Io are approximately equal or not. If they are not approximately equal, the process moves to step 304 and the nozzle 5 is moved to the one with a larger detected value, that is, the one with brighter sputtering light.
Motor MX to bring it closer.

MY is driven by an amount corresponding to the difference in light amount.

The drive amount of each motor Mx, MY may be determined using table data created in advance in correspondence with the difference in light amount.

Furthermore, the distribution device 13 may determine the amount of distribution for each axis XY based on the arrangement of the light receiving sections 9 shown in FIG.

In step 305 following step 304, the workpiece W is moved a little distance, the process proceeds to steps 301 and 302, the piercing process is performed again, the amount of light is measured, and step 30
In Step 3, confirm that the spatter scattering has become homogeneous.

Since each detected value became almost equal in step 303, it was determined that the spatter scattering was homogeneous, that is, the nozzle 5
After confirming that the center of the laser beam LB is on the center line of the laser beam LB, the centering work is completed.

FIG. 4 is a flowchart of the centering process executed in the actual piercing process. This is because in actual processing, for example, when cutting a large number of products from a single workpiece using a laser, each product is pierced inside or outside before it is processed. The centering of the nozzle 5 is adjusted for each piercing process.

Wait for piercing to be performed in step 401, then step 4
At steps 02 to 404, centering processing similar to steps 302 to 304 in FIG. 3 is performed. However, since this example is for making fine adjustments in a one-time piercing process, there is no process corresponding to step 305 in FIG. 3.

Adjustment amount of nozzle 5, that is, each motor MX.

The driving amount of MY is determined in the same way as shown in Fig. 3, but
In this example, since a large adjustment may have the opposite effect, it is better to set the amount of adjustment to be sufficiently small. Also, instead of adjusting each time for each piercing,
The adjustment may be made using the average value of multiple piercings (for example, three times). Furthermore, in order to perform more optimal adjustment, the amount of adjustment may be determined by fuzzy inference.

In this case, the fuzzy inference is the detected value IAnIB,
The difference between the detection values for the light condensing parts 9 arranged opposite to each other among IC and ID, that is, IA-1c and IBI.

A method can be considered in which a membership function is determined for each direction, and other appropriate membership functions are determined to determine the drive amount of the motor in each opposing direction.

As described above, the nozzle adjustment device for a laser processing machine according to an embodiment of the present invention can detect the amount of spatter scattered around the center line of the laser beam LB via the light receiving section 9 and the optical fiber 8. The nozzle 5 can be automatically adjusted so that spatter during piercing is uniformly scattered around the center line of the laser beam LB.

Therefore, since the nozzle 5 can be automatically adjusted, there is no need for the operator to approach the processing head 1, and nozzle centering can be performed safely. Furthermore, since the amount of nozzle adjustment is performed according to the amount of sputtering light, the amount of adjustment is appropriate, and highly accurate adjustment can be performed quickly.

Furthermore, as shown in FIG. 4, since fine adjustments can be made using data from actual machining, distortions due to thermal distortion etc. can be absorbed even during long-term use.

In the above embodiment, the nozzle holder 3 is used as the nozzle moving means.
．． 4 and the motors MY and MX for moving these nozzle holders 3.4 have been shown, but the nozzle moving means is not limited to this. That is, for example, the nozzle 5 may be configured such that its tip hole is swingable with respect to the base, and centering may be performed by the swinging action. Also, screw 6,
7 may be replaced by a wedge member, and the nozzle holder 3.4 may be moved by the movement of the wedge member. Furthermore, actuators other than the electric motors Mx and MY can also be used.

Further, in the above embodiment, the optical fiber 8 serving as the spatter detection means is provided with the light receiving section 9, but the light receiving section 9 may be provided with a cover member in order to prevent spatter from flying during normal operation. Furthermore, the light receiving section 9 is not limited to that shown in FIG.

Further, in the above embodiment, the comparison device 11 and the distribution device 13 as adjustment control means are provided independently of the NC device, but it is also possible to incorporate these functions inside the NC device.

〔Effect of the invention〕

As described above, since the present invention is a nozzle centering device for a laser processing machine as described in the claims, nozzle centering can be automatically performed safely, with high precision, and at high speed.

[Brief explanation of the drawing]

FIG. 1(a) is a longitudinal cross-sectional view of a laser processing head implementing the present invention, FIG. 1(b) is a longitudinal cross-sectional view in a direction perpendicular to FIG. 1(a), and FIG. 2 is a longitudinal cross-sectional view of the laser processing head according to the present invention. A system configuration diagram of the nozzle centering device shown with the control device connected to the bottom view of the head, Figure 3 is a flowchart showing the centering process by experimental piercing, and Figure 4 shows the actual centering process by piercing. FIG. 1... Laser processing head 2... Laser beam condensing lens 3... (For moving in the Y direction) Nozzle holder 4... (For moving in the X direction) Nozzle holder 5... Nozzle 8... Optical fiber 9...Receiver department agent Patent attorney Hidekazu Miyoshi

Claims (1)

[Scope of Claim] In a nozzle centering device for a laser processing machine that performs laser processing on a workpiece by irradiating a laser beam from a nozzle provided in a laser processing head, a nozzle moving means for moving the nozzle in a plane orthogonal to the irradiation direction; a spatter detection means for detecting the amount of spatter scattered from the workpiece at a plurality of outer peripheral positions of the nozzle; A nozzle centering device for a laser processing machine, characterized in that an adjustment control means is provided for adjusting and moving the nozzle via the nozzle moving means so that spatter becomes uniform with respect to the center line of the laser beam.