JP3115060B2 - Laser processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method for cutting a work by using a laser beam, and mainly relates to a spatter generated at the time of piercing for forming a through hole at a starting point of the cutting at a predetermined position of the work. The present invention relates to a laser processing method that enables removal.

[0002]

2. Description of the Related Art Generally, when laser processing is performed on a work such as an iron plate by a processing head of a laser processing apparatus, a through hole is formed on one of the unused cutting sides, and laser cutting is performed from this through hole. There is a method of performing processing, and a piercing method of processing a through-hole at the starting point of the cutting process from the beginning and performing a cutting process from the through-hole into a desired shape.

[0003]

In the former laser processing method, there is a problem that the material after cutting is wasted, but on the other hand, the sputter does not adhere to the cut processing surface, so that the processing shape is improved. The occurrence rate of defective products can be reduced.

In the latter piercing method, waste of material can be reduced. However, spatter in a molten state adheres in a raised state near the work surface of a through hole formed first, and after piercing, During the cutting process, there is a problem that cutting is not performed smoothly due to the above-mentioned spatter, or a cut edge becomes uneven, and a problem that the occurrence rate of defective products increases. In particular, in the case where the gap control is performed while detecting the gap amount between the work surface and the nozzle tip, the gap control becomes unstable at the swelling portion of the sputter, the nozzle swings up and down, and stable processing can be performed. And a clean cut surface could not be obtained.

An object of the present invention is to perform a smooth cutting process by removing spatters adhering to the surface of a work or reducing a bonding force between the work and the spatter during a transition from piercing to cutting of the work. It is another object of the present invention to provide a laser processing method capable of smoothing a cut surface of a work and preventing occurrence of defective products.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a laser processing method for cutting a workpiece by using a laser beam, wherein a through hole is formed by piercing at a predetermined position serving as a processing start point of the workpiece. , next Ide
Just above the piercing position and at the time of piercing
Once the nozzle is moved to a higher position,
Reduce the gas pressure to a higher pressure than during the piercing.
After recombination, it has adopted a means of performing flight <br/> dispersion removal of sputter deposited on the vicinity of the opening of the through hole formed in the work surface gradually lowers the nozzle.

[0007]

According to the present invention, after piercing a through hole in a work, the spatter generated near the outer surface of the through hole of the work is scattered by a gas injected from a processing nozzle side, so that cutting is performed with spatter adhered to the work. Processing is not performed, and therefore, the cut surface is smoothened without generating irregularities on the cut surface due to sputtering, and generation of defective products can be suppressed. Also, when spatter is not scattered by the gas injected from the processing nozzle side,
Since the bonding force between the work and the sputter is reduced, the sputter is easily scattered from the work surface by the pressure of the assist gas when moving to the work cutting of the work by the processing head, so the work surface becomes clean and cut. Is performed smoothly.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. An apparatus used for this laser processing method will be described with reference to FIG. 2. A laser beam L output from a laser oscillator 1 is guided by a mirror or the like and is incident on a lens 4 of a processing head 3. At the outer focal point of Processing head 3
The assist gas is supplied from the assist gas supply device 6, and the assist gas 5 is ejected from the nozzle 5 coaxially with the laser beam L to process the work W.

The machining head 3 is controlled by a servo control circuit 7 along a machining path, for example, in a plurality of axes in X, Y, and Z directions. At the same time, the distance from the tip of the nozzle 5 to the surface of the workpiece W, that is, the gap amount is detected by the nozzle 5 or the gap sensor 8 provided in the vicinity of the nozzle 5, and the gap controller 9 determines the distance based on the detected data. The height of the nozzle 5 is controlled so that the gap amount during processing becomes a predetermined amount.

Further, when piercing is performed on the work W, the machining head 3 is moved in the Z-axis direction, ie, the optical axis direction via the servo control circuit 7 by the NC device 10 shown in FIG. The gap amount between the workpiece and the surface of the work W is controlled as shown in FIG. At the same time, the laser oscillation control circuit 11 shown in FIG.
Laser processing is performed as follows while controlling the output value of the laser light L output from the laser oscillator 1.

At the start of piercing, after setting the processing head 3 at a predetermined height position, a through hole h is formed in the work W, as shown by the chain line in FIG. 1 and FIG. After the through hole h is formed, the processing head 3 is instantaneously moved upward by a predetermined height as shown by a solid line in FIG. 1, and the output of the laser oscillator 1 is pierced as shown in FIG. As shown in FIG. 3C, the pressure of the assist gas supplied from the assist gas supply device 6 is set higher than that at the time of piercing, and the processing head 3 is moved as shown in FIG. Gradually lower. Due to the strong pressure of the assist gas A injected from the processing head 3 at the highest position, the sputter S in the molten state attached to the vicinity of the surface of the through hole h of the workpiece W is blown outward. Further, since the laser beam L is output from the laser oscillator 1, the intrusion of the sputter S into the through hole h is prevented. For this reason, the spatter S attached to the vicinity of the outer surface of the through hole h of the work W is reliably removed.

Therefore, when cutting is performed by moving the processing head 3 relative to the work W in the horizontal direction, since the spatter S does not exist on the work surface, the gap sensor 8 detects an accurate gap between the work W and the work W. By performing the detection, the work W is cut smoothly under stable gap control, and the cut surface does not become uneven, so that the generation of defective products can be suppressed. At the time of the cutting, the pressure of the assist gas A is set to a pressure lower than that at the time of blowing off the sputter S.

In this embodiment, the processing head 3 is gradually lowered, in order to prevent the through hole h from being clogged by piercing. Also, as shown in FIGS. 3B and 3C, after the piercing is completed,
The laser oscillation output and the assist gas pressure were temporarily stopped in order to prevent the laser output and the assist gas from being excessively supplied to the work until the processing head 3 starts descending.

In this embodiment, as an example of processing conditions, the vertical movement amount of the processing head 3 is ± 50 mm, the elevating speed is 500 mm / min, the laser output is 300 W, and the assist gas (0 ₂ ) pressure is the material of the work. Is SS41 (thickness 16 mm), 3.0 / cm ² , SUS (thickness 1
3 mm), the gas pressure is set to 1.0 kg / cm ² .

At the time of cutting, the height of the processing head 3, the laser oscillation output, and the assist gas pressure are set to appropriate values depending on the material and thickness of the work. By the way, even when the assist gas pressure is low, welding of the sputter S to the surface of the work W can be prevented.
Difficult to blow off. However, even when the sputter S is not scattered, the bonding force between the work W and the sputter S is reduced. Since S is easily scattered, the cutting process is performed smoothly.

Next, another embodiment of the present invention will be described with reference to FIG. In this embodiment, an annular nozzle portion 21 for further injecting assist gas is formed on the outer periphery of the processing head 3, and after finishing the piercing hole processing on the work W, the processing head 3 is held at the cutting height position. The high-pressure assist gas A is jetted toward the sputter S from the jet nozzle 21 while keeping the spatter scattered. In the case of this alternative example, there is no need to move the machining head 3 up and down, so that the efficiency of cutting can be improved.

It should be noted that the present invention is not limited to the above-described embodiment, and may use another source of compressed air in place of the assist gas to scatter the spatter, without departing from the spirit of the present invention. The configuration of each unit can be arbitrarily changed and embodied.

[0018]

As described above in detail, when the present invention is to shift to cutting from piercing machining a workpiece, Pi
Just above the ashing position and higher than when piercing
Move the nozzle once to
Pressure was switched to a higher pressure than during the piercing
After that, the nozzle is gradually lowered to remove the spatter adhering to the surface of the work.
There is no spatter on the surface, so that the work can be cut smoothly and the occurrence rate of defective products can be suppressed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a laser processing method embodying the present invention.

FIG. 2 is a configuration diagram illustrating a control circuit of the laser processing head.

FIGS. 3A, 3B, and 3C are graphs each illustrating a laser processing method.

FIG. 4 is a sectional view for explaining another laser processing method of the present invention.

[Explanation of symbols]

1 laser oscillator, 3 processing head, 5 nozzles, 6
Assist gas supply device, 11 laser oscillation control circuit, L
Laser light, A assist gas, W work, h through hole.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23K 26/14 B23K 26/00

Claims (1)

(57) [Claims] 1. A laser processing method for cutting machining of a workpiece by the laser beam, the through-holes at predetermined locations to be processed starting point of the work is formed by piercing, the following physician
Above the piercing position and at the time of piercing
Move the nozzle once to a higher position
Switch the cyst gas pressure to a higher pressure than during the piercing.
After recombination Ri, the laser processing method and performing <br/> scattering removal of sputter deposited on the vicinity of the opening of the through hole gradually lowers the nozzles formed on the workpiece surface.