JPH1190670A - Method for removing fused material sticking to work surface in piercing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove a metallic fused material generating at the time of piercing and to reduce or to prevent the ratio of defective machining by controlling a laser beam output and an assist gas pressure in the laser machining of plate materials, and incorporating in the machining process the method of operating or turning a machining head nozzle. SOLUTION: A metallic fused material forms a deposited part on the inner peripheral part of a pierced hole and sticks in a mustache or chevron shape. With a profiling sensor turned off, or by ignoring the sensor alarm, a sensor nozzle part 2 is rotated in a circular motion around the pierced hole along a circle, which is rather large compared with the outer circumference of the fused deposit sticking near the periphery of the pierced hole, an assist gas G with high pressure is sprayed and a round is taken in the circular orbit. Against the fused deposit, a reversed flow of a high pressure gas is generated towards the center of the pierced hole from the outer circumference, to peel and remove easily the fused deposit. Then, the profiling sensor is turned on and ordinary machining is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing a melt adhered to a material surface during piercing in laser processing of a plate material or the like.

[0002]

2. Description of the Related Art In laser processing of a plate material or the like, it is customary to perform piercing processing for penetrating a minute hole at the start of cutting processing.

[0003]

However, in the above-mentioned conventional example, while the material and the processing method are diversified, the problem arises more or less regardless of the kind of the material. During piercing in machining or piercing in clean cutting of stainless steel, the molten metal adheres to the periphery of the piercing hole in a whisker-like (hereinafter referred to as "whisker-like") or mountain-like shape, and the sensor nozzle And the molten metal come into contact with each other and become in an electrically conductive state.
Deterioration of the material on the cutting path causes machining errors such as poor cutting.In addition, there is a method in which the assist gas during piercing is set to a high pressure and sprayed onto the metal melt adhesion part, but it is pressed from above. As a result, the assist gas escapes from the pierced hole and the effect is not obtained.In addition, even if it is blown off by the air blow nozzle from the horizontal direction separately from the copying sensor nozzle for processing, there is no effect on the front side of the pierced hole. However, there is no effect on the other side, and there is a case where oil is applied to the piercing point of the workpiece before piercing to reduce the adhesion of metal melt, but until the problem is solved Has not been reached.

The present invention has been made by paying attention to the above-mentioned point, and gives a swirling circular motion to a nozzle of a processing head to control the output of a laser beam and an assist gas to remove a metal melt generated at the time of piercing. Can be removed,
An object of the present invention is to provide a method for removing a melt adhered to a material surface during piercing, which can reduce or prevent a processing failure rate.

[0005]

The present invention can solve the above-mentioned problems by providing the following constitution. (1) In laser processing of a plate material, the output of laser light and the pressure of the assist gas are controlled, the nozzle of the processing head is turned, and the metal adhering to the material surface generated at the time of piercing performed at the start of cutting processing is melted. A method for removing a melt adhered to a material surface during piercing, wherein a method of operating a nozzle of a processing head capable of removing an object is incorporated in a processing step.

(2) The method of operating the nozzle of the processing head is as follows.
Giving a swirling circular motion larger than the outer peripheral edge of the molten deposit to the nozzle of the processing head around the piercing position, blowing away assisting gas at a high pressure to blow away the metal melt adhering to the material surface, and removing it. The method for removing a melt adhered to a material surface during piercing according to the above (1).

(3) The method of operating the nozzle of the processing head is as follows.
The nozzle of the processing head is given a small circular motion around the piercing position to suppress and control the output of the laser beam and cut only the metal melt near the piercing while controlling the injection pressure of the assist gas to control the metal. The method for removing a melt adhered to a material surface during piercing according to the above (1), wherein the melt is blown off and removed.

[0008]

Embodiments of the present invention will be described below.

FIG. 1 is a flowchart of piercing and the removal of molten metal deposits according to the present invention. FIG. 2 is a side sectional view showing the configuration of a main part of a working head and the situation during piercing.
FIG. 4A is a plan view showing an example of a normal machining path starting from a pierced hole, FIG. Is a circle larger than the outer peripheral edge of the melt, and a cross-sectional enlarged view showing a situation in which the whisker-like melt is blown off and removed by the assist gas. FIG. FIG. 5 (a) is an enlarged plan view showing a case where the trajectory is a circle larger than the outer peripheral edge of the molten material, and FIG. FIG. 5 is an enlarged side sectional view, and FIG.
6A and 6B are enlarged plan views showing the size of FIG.
FIG. 3 is an explanatory view showing an external side surface and an operation axis as an example of a laser processing head.

Referring to the drawings, 1 is a processing head, 2 is a sensor nozzle, L is a condenser lens,
Laser light LB propagated from an oscillator (not shown) is converged by a condenser lens L and condensed toward a processing point, and an assist gas G is introduced from a connection portion of the processing head and irradiated to the processing point. It is injected so as to enclose the laser light LB. g is a gap, which indicates a set distance between the workpiece W and the tip of the sensor nozzle unit 2.

The sensor nozzle section 2 has a function of adjusting the narrowing of the assist gas or the like and a function of sensing and adjusting the nozzle gap with the work W.

(Example 1) A metal melt generated at the time of piercing, which is a starting point of cutting, forms a weld at the inner peripheral portion of the piercing hole, and has a beard shape (FIG. 4A) or a peak. Adhere to the shape.

In order to remove the molten metal deposits, the scanning sensor is turned off, or the sensor alarm is ignored, and the sensor nozzle unit 2 shown in FIG. A high pressure assist gas is sprayed along a circle larger than the outer peripheral edge of the molten deposit adhering to the vicinity of the peripheral edge of the piercing hole around the piercing hole at a high pressure to make a round of the circular orbit. As a result, a high-pressure gas flows backward from the outer periphery toward the center of the piercing hole with respect to the molten deposit (FIG. 4A), and the molten deposit is easily peeled off and can be removed (FIG. 4).
(B)). Then, the copying sensor can be turned on to perform normal cutting.

(Embodiment 2) When the scanning sensor is turned off or a sensor alarm is ignored, as shown in the laser head path of FIG.
Is made to make a small circular motion so as to rotate around the outer periphery of the piercing hole around the piercing hole, and makes a round of the small circular orbit, and the laser beam LB is applied to the vicinity of the welded portion serving as the base of the melt adhered to the piercing hole periphery. In addition, the assist gas G is injected while cutting only the welded material by irradiating with a low output such as the scribe processing, and the cut welded pieces and the remaining fine pieces can be blown off and removed (FIG. 5A). (B)).

Then, as described above, the copying sensor is turned on.
Then, a normal cutting process can be performed.

Next, the operation will be described with reference to the piercing and the flowchart for removing the molten metal deposit shown in FIG.

S1 is a step of performing piercing, in which piercing is performed at the set gap g. In step S2, it is determined whether or not there is a molten deposit at the piercing point, and there is a molten deposit. If it is determined that the processing is performed, the process proceeds to step S3, where the Z-axis (vertical direction of the processing head) scanning sensor is set to OFF, and in step S4, the processing head 1 is moved along the Z-axis in order to prevent the nozzle from coming into contact with the molten deposit. Is raised by several millimeters, and the process proceeds to step S5. If it is determined that laser light is not output, the type and pressure of the assist gas G are set in step S6. The pressure of G is usually set to a high pressure. Next, in step S7, the turning circular motion of the nozzle is set. In this case, the turning radius is set so that the nozzle turns around the piercing hole with a circle larger than the outer peripheral edge of the molten deposit. In step S8, the high-pressure gas is injected while the nozzle is swirled to make a round, and the deposit is blown off by the gas flow flowing backward from the outer peripheral side of the molten deposit toward the center of the piercing hole, thereby completing the operation of removing the molten deposit. In the next step S9, the output of the laser beam LB that has been stopped is restored, and the process proceeds to the next step S15, where the nozzle is returned to the piercing point, and in step S16, the Z-axis scanning sensor is turned on, and the processing head is turned on. Taking advantage of the vertical scanning sensor function of 1 above, in the next step S17, the process shifts from the normal approach processing to the path cutting operation, and proceeds to the next process.

On the other hand, if it is determined in step S5 that the laser beam LB is to be output, the process proceeds to step S10, in which the output of the laser beam LB is set to a low output equivalent to that for scribe processing in order to cut only the molten deposit. And then step S11
The type and pressure of the assist gas G are set in step S6. In this case as well, the pressure is set to a slightly higher pressure side in the same manner as in step S6 described above. In step S12, the circular motion of the nozzle is set. If the deposit is in the form of a beard, the welded portion is located on the upper edge of the pierced hole, so a small turning radius is set around the pierced hole so that the adhered portion turns slightly larger than the size of the pierced hole. In step S13 of
Irradiates low power laser beam LB and assist gas G
The nozzle of the processing head 1 makes a small turn while ejecting, and cuts and blows off the adhered material. When the operation of removing the adhered material is completed, the output of the laser LB is returned to the original in step S14, and the same as described above. In step S15, the nozzle is returned to the piercing point, and in step S16, the Z-axis scanning sensor is turned on.
In the next step S17, the process moves from the normal approach processing to the path cutting operation, and proceeds to the next step.

In addition, continuous oscillation (CW: Contin
At the time of piercing, it may be possible to remove extraneous matter by blowing assist gas.In addition, the path of the laser beam LB may vary depending on the degree of molten extraneous matter such as whisker-like deposits and mountain-like deposits. Needless to say, the turning radius of the nozzle to be formed, the output of the laser beam LB, the type of the assist gas (normally, air is sufficient), and the pressure can be freely selected on a case-by-case basis.

[0020]

According to the present invention, it is possible to give a turning circular motion to the nozzle of the processing head, control the output of the laser beam and the assist gas, remove the metal melt generated at the time of piercing, and obtain defective processing. The effect is that the rate can be reduced or prevented.

[Brief description of the drawings]

FIG. 1 is a flowchart of a piercing process and a removal of molten metal deposits according to the present invention.

FIG. 2 is a cross-sectional side view showing a configuration of a main part of a processing head and a state at the time of piercing.

FIG. 3 is a plan view showing an example of a normal machining path starting from a pierced hole.

4A is an enlarged side sectional view showing the state of adhesion of the whisker-like melt and the state of the flow of the assist gas, and FIG. 4B shows the trajectory of the swirling motion of the nozzle as a circle larger than the outer peripheral edge of the melt. , A side cross-sectional enlarged view showing a situation in which the whisker-like melt is blown off by the assist gas, and (c) a plane enlargement showing a case where the trajectory of the swirling circular motion of the nozzle is a circle larger than the outer peripheral edge of the melt; Figure

FIG. 5A is an enlarged side sectional view showing a trajectory of a small swirling circular motion of a nozzle and a state in which a molten adhered substance is blown away while being cut, and FIG. 5B shows the size of FIG. 5A. Enlarged plan view

FIGS. 6A and 6B are explanatory views showing an external side surface and an operation axis as an example of a laser processing head; FIGS.

[Explanation of symbols]

 1 Processing Head 2 Sensor Nozzle G Assist Gas g Gap LB Laser Light L Condensing Lens W Work

Claims (3)

[Claims] 1. In laser processing of a plate material or the like, the laser beam output and the pressure of an assist gas are controlled to rotate a nozzle of a processing head and adhere to a material surface generated at the time of piercing performed at the start of cutting processing. A method for removing a melt adhered to a material surface during piercing, wherein a method of operating a nozzle of a processing head capable of removing a metal melt is incorporated in a processing step. 2. A method of operating a nozzle of a processing head, wherein the nozzle of the processing head is provided with a swirling circular motion larger than the outer peripheral edge of the molten deposit around the piercing position, and the assist gas is ejected at a high pressure to adhere to the material surface. 2. The method according to claim 1, wherein the molten metal is blown off and removed. 3. A method of operating a nozzle of a processing head, wherein the nozzle of the processing head is given a small circular motion around the piercing position to suppress and control the output of a laser beam to cut only a metal melt near the piercing. 2. The method for removing a melt adhered to a material surface during piercing according to claim 1, wherein the metal melt is blown off and removed by controlling the injection pressure of the assist gas while controlling.