JPH02155588A - Method and device for laser cutting - Google Patents

Abstract

PURPOSE:To execute the laser cutting for obtaining a cutting plane whose roughness is small by providing a suction device of inert gas which passes through a cutting part on a metallic plate, supplying compressed air of specific pressure to the device and exhausting the inert gas, and using an emitted light of a high speed axial-flow type carbon dioxide gas laser equipment as a laser light. CONSTITUTION:Inert gas 6 is supplied to one side of a work 5 of a metallic plate, and by irradiating this one side by a laser light 4, the metallic plate work 5 is brought to laser cutting. In this state, on the other side of the metallic plate work 5, suction devices 11, 12 to which the inert gas 6 flows in through a cutting part are provided. Subsequently, by supplying compressed air 7 of pressure of at least 5kgf/cm<2> to the middle of this suction device 12, the inert gas is exhausted. An emitted light of a high speed axial-flow type carbon dioxide gas laser equipment is used as the laser light 4. In such a way, the laser cutting for obtaining a cutting plane whose roughness is small can be executed.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for laser cutting a plate material and an apparatus therefor.

(Prior Art) Various proposals have been made to reduce the amount of dross remaining on the back surface of a metal plate cut with a laser beam.

For example, a method has been tried in which gas is blown from both sides of the back side of the laser irradiated and cut part of the metal plate in the direction of cutting progress to blow off the dross that comes out on the back side (Nikkei Mechanical, July 2, 1984). No., P.

118), and a dust collector as shown in Fig. 4, which collects this blown dross, has also been put into practical use.

By the way, this dust collector 1 is provided with an exhaust duct connection port 2a to which a duct (not shown) connected to an exhaust device (not shown) is connected to the right side wall of the lower inverted Ω-shaped dust collection box 2. A removable air filter 2b that vertically partitions the inside of the dust collection box 2 is provided inside the exhaust duct connection port 2a. Further, the lower end of a suction duct 3 is connected to the upper surface of the dust collection box 2, and a substantially cylindrical exhaust passage 3a passing vertically is provided inside the suction duct 3.
The upper end has a truncated conical shape, and a suction port 3b is formed at the upper end. In addition, the upper surface of the suction duct 3 is provided with an outlet hole 3C shaped like a letter left and right.The lower ends of the outlet holes 3C communicate with each other, and the communication hole on the right side is connected to the compressed air connection provided on the right side surface. It communicates with the plug 3a.

The dust collecting device 1, which is composed of the suction duct 3 and the dust collecting box 2, is provided at the bottom of a notch (not shown) provided in the middle of the table on which the workpiece 5 to be cut is placed. Dross attached to the lower surface of the cut workpiece 5 is removed by compressed air blown from the blowout hole 3C into the dust collection box 2 below.
dropped inside.

However, although this method can reduce the amount of dross adhering to the bottom surface of the workpiece 5, the dross moves forward in the direction of laser cutting, and small pieces of dross may be deposited on the bottom surface of the cut part, especially for stainless steel materials where dross tends to remain. It remains in the form of a stream. This is also considered to be because the compressed air blown from both sides of the cut portion collides below the cut portion and the flow velocities cancel each other out.

Therefore, in order to further reduce the amount of dross attached, we
A method as shown in FIG. 6 has been attempted. (Showa 60
(Refer to Proceedings of the 2016 Autumn Conference of the Japan Society of Precision Machinery Engineers, P, 685, and 1985, Proceedings of the same above, P, 661).

This method uses stainless steel (SO330) as shown in Figure 5.
4) While supplying nitrogen gas from above the work 5 of the plate, irradiate the laser beam 4 and cut the compressed air 7 from the bottom right of the back side as shown in Fig. 6. The dressless product on the right side is obtained by spraying at an angle of β1 (within 30° in each case) so that the dross 5a adheres only to the left side.

(Problem to be Solved by the Invention) However, with this method, when the cut shape of the workpiece 5 is a straight line, the nozzle of the compressed air 7 can always follow the cutting progress direction within a predetermined angle, but when the workpiece 5 has a small curvature For workpieces with parts, it is difficult to make the nozzle direction follow sudden changes in the laser cutting direction.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a laser cutting method and apparatus that can easily cut a workpiece such as a stainless steel plate without loss.

[Structure of the invention]

(Means and Effects for Solving the Problems) The present invention provides a laser cutting method and apparatus for cutting a metal plate by supplying an inert gas to one side and irradiating a laser beam with the above-described method for cutting the metal plate on the other side. An inhalation device is provided through which the inert gas enters through the cut, and in the middle of the inhalation device at least 5 gf/
By supplying compressed air at a CD pressure to exhaust the inert gas and using the output light of a high-speed axial flow type carbon dioxide laser device as the laser beam, it is possible to roughen one side of stainless steel material without leaving dross on the back side of the cut part. This is a laser cutting method and device for obtaining a small cut surface.

(Example) Hereinafter, an example of the laser cutting method and apparatus of the present invention will be described with reference to the drawings.

In FIG. 1, a 3m thick workpiece 5 made of stainless steel (SO5304) is placed on an XY child table (not shown).
．． A suction pipe 11 with a 7-shaped cross section is provided about 5 am apart, and at the lower end of this suction pipe 11 there is an outer cylinder 12a and an inner cylinder 12b''.
The upper end of the discharge pipe 12 constructed as c' is fitted, and the outer cylinder 12a is constructed by combining the upper outer cylinder 12a and the lower outer cylinder 12a2. A joint of a pipe 12c that supplies compressed air 7 at a pressure of 5 kgf/- is connected, and a flange portion at the upper end of the lower outer cylinder 12a2 is attached to the upper surface of the lower dust collection box 2.

XY (not shown) with the laser cutting device configured in this way
When cutting the workpiece 5 placed on the table,
A valve (not shown) provided at the end of the pipe Ie12c is opened to send compressed air 7 into the exhaust pipe 12, and nitrogen gas 6 is sent into the laser nozzle (not shown) to emit laser light 4.
is irradiated onto the workpiece 5 to drive an XY child table (not shown). Then, the nitrogen gas 6 supplied to the cutting section from a laser nozzle (not shown) is accelerated at the lower end of the outer cylinder 12a and exits the cutting section as a laminar flow with the compressed air 7 exhausted, and flows downward as shown by the arrow 6a. It is sucked in and discharged to the outside as shown by the arrow 6b.

FIG. 2 is a diagram showing cutting results by the present laser cutting device, and FIG. 3 is a diagram showing, as a comparative example, the cutting results when the compressed air 7 of FIG. 1 is not supplied.

The cutting conditions are: Laser light; 1.2KW high-speed axial flow type carbon dioxide laser transverse mode is single mode (TEMo).

Mode) Table movement speed: 1.5m/min Workpiece: Stainless steel (SUS304) plate, 3.0mm thick Nozzle outlet diameter: 2m Gap between the lower end of the nozzle and the workpiece: Approximately 1m Inner diameter of the upper end of the suction pipe: 130mm Between the upper end of the suction pipe Gap between the workpiece and the workpiece: approximately 0.5++nNitrogen gas pressure: 7Kgf/aJ Compressed air pressure: 5Kgf/cJ.

In Figure 2, (a) is a photograph showing the cut workpiece 5, (b) is an enlarged photograph of the cut surface, and (c) is a stylus-type surface roughness measuring device that measures the surface roughness of the central part in the thickness direction of the cut portion. This is a graph showing the results measured by .

As shown in Figure 2 (a), the work cut by this laser cutting method and its device not only has no dross attached to the back side, but also has no oxidation on the cut surface as shown in Figure 2 (b). It is shiny as shown in Figure 2(a).

As shown in FIG. 2(C), the cut portion had a small surface roughness.

On the other hand, in the comparative example shown in FIG. 3, the result is shown in FIG. 3(a).

As shown in (b), dross remains, and as shown in Fig. 3 (c), the cut surface has roughness.The average value (Ra) is more than twice that of Fig. 2 (c), and the maximum value (Rmax) is approximately It has increased four times.

As described above, according to the present invention, it is possible to cut stainless steel plates, etc., which have traditionally been difficult to cut without dross, with a glossy cut surface without an oxide film, and this is a feature of the high-speed axial flow type carbon dioxide laser processing machine. We were able to demonstrate this even on stainless steel plates.

In the above embodiment, the XY child table is moved. However, when moving the laser nozzle, the absorption tube 11 is also moved by the same NC device, and the piping 12c can be replaced with a flexible hose. As shown in the figure, it is not necessary to change the blowing angle of the compressed air 7 according to the change in the direction of the laser cutting line.

Further, in the above embodiment, the inner diameter of the upper end of the suction pipe 11 is set to a size in which the workpiece 5 can fit, but it is set as small as possible (for example, 10nm).
n) Alternatively, the suction force for the nitrogen gas 6 may be increased by reducing the intrusion of air from the lower surface of the workpiece 5. In this case, it has the effect of preventing the adhesion of dross, and also has the advantage that it can be used even when cutting the workpiece 5 near the end of the material.

Furthermore, a thin polyester plate shaped like a disc spring may be attached to the lower surface of the upper flange portion of the suction pipe 11, and the outer periphery may be applied to the material of the workpiece 5 to further reduce the intrusion of air.

In the above embodiment, the material of the workpiece 5 is stainless steel.
(SUS304) is used as a plate, but other materials such as stainless steel plates, aluminum, titanium, etc. that easily collect dross may be used.

Furthermore, in the above embodiments, nitrogen gas was used as the gas to be supplied to the cutting surface, but other inert gases (eg, argon, helium) may be used.

〔Effect of the invention〕

As described above, according to the present invention, in the laser cutting method and apparatus for cutting a workpiece by irradiating a metal plate with a laser beam and supplying an inert gas as an assist gas, the inert gas is cut on the underside of the metal plate. providing an inhalation device for inflow through the section;
Compressed air with a pressure of at least 5 Kgf/al was supplied to the middle part of this suction device to accelerate the exhaust of inert gas, and the output light of a high-speed axial flow type carbon dioxide laser device was used as the laser light, so dross was generated. It is possible to obtain a laser cutting method and an apparatus therefor, which can produce a cut surface with small roughness without forming dross on the lower surface of the cut even when the workpiece is made of easy-to-cut stainless steel or the like.

[Brief explanation of the drawing]

FIG. 1 is a vertical joint view showing an embodiment of the laser cutting method and device of the present invention, and FIG. 2 is a diagram showing the operation of the laser cutting method and device of the present invention. 2(b) is an enlarged photograph of the cut portion, FIG. 2(c) is a graph showing the roughness of the cut portion, and FIG. 3 is an implementation of the laser cutting method and apparatus of the present invention. FIG. 4 is a longitudinal sectional view of a conventional laser cutting method and its device; FIG. 5 is a longitudinal sectional view of a conventional laser cutting method different from FIG. 4; FIG. 5 is a bottom view of FIG. 5. FIG. 4... Laser light 5... Workpiece 6... Nitrogen gas as an inert gas 11... Suction pipe 12... Discharge pipe (87
33) Agent, patent attorney Yoshiaki Inomata (and one other person) drawings, 5 documents (G) Figure 2 Figure 3 Procedures available ■Authentic document (spontaneous)! Figure 5

Claims (2)

[Claims] (1) In a laser cutting method in which an inert gas is supplied to one side and a laser beam is irradiated to the one side to cut the metal plate, the inert gas flows into the other side of the metal plate through the cutting part. The inert gas is discharged by supplying compressed air at a pressure of at least 5 Kgf/cm^2 to the intermediate part of the inhalation device, and the laser beam is combined with the output light of a high-speed axial flow type carbon dioxide laser device. A laser cutting method characterized by using. (2) A laser cutting device in which an inert gas is supplied to one side and a laser beam is irradiated to the one side to cut a metal plate, including a high-speed axial flow type carbon dioxide laser device that emits the laser beam, and the metal plate. and a suction device whose upper side is provided close to the other side and whose intermediate portion is supplied with compressed air at a pressure of at least 5 Kgf/cm^2 and which discharges the inert gas flowing from the cutting portion to the outside. A laser cutting device characterized by: