RU2471600C1 - Method of gas laser cutting of large-sixe parts from composite materials and device to this end - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to gas laser cutting of composite materials. Proposed method comprises feeding laser beam to machined surface and process gas, aligned therewith, collimating laser beam, embedding it in machined article and displacing by preset program in the presence of process fluid. Fluid jet is fed as swirled coaxially with laser beam into cutting thermal effect zone. Proposed device comprises laser cutter case wit focusing lens, union to feed process gas, nozzle, and cylindrical vessel with annular channel to feed process fluid. Said annular channel incorporates hollow tapered adapter with inner surface representing helical grooves to swirl fluid flow.

EFFECT: higher quality of cutting.

4 cl, 3 dwg

Description

Technical field

The invention relates to mechanical engineering, namely to laser processing of materials, in particular to gas-laser cutting of composite materials, and can be used in the aerospace industry in the manufacture of large-sized parts from composite materials to improve their quality.

State of the art

A known method of gas-laser cutting of composite materials (RU 2382693 dated July 17, 2008), the method includes supplying a laser beam to a work surface, supplying a process gas coaxially with a laser beam, collimating a laser beam, focusing it at a predetermined depth of a workpiece, and moving according to a predetermined program . Cutting is carried out in a liquid medium. The product is placed in a water bath on cone pins with an excess of the water level above the surface of the product equal to 10-15 mm.

The technological process is carried out by an ytterbium fiber laser with a laser beam deepening into the workpiece by 0.2-0.4 of its thickness. The movement of the laser beam is carried out at a speed of 1.2-1.8 m / min.

The disadvantage of this method, selected as a prototype, is the limitation of the size of the processed product due to the need to immerse it in a bath with water and the inability to process products of complex spatial shapes due to the inaccessibility of the laser beam.

A known method of gas-laser cutting of metal materials and a device for implementing the method (RU 2089365, V23K 26 / 14.1997), comprising supplying under pressure a process gas into the torch body coaxially with a laser beam, additionally water is supplied to the cutting zone at a flow rate of 0.01 -4.0 ml / mm cut. The device for gas laser cutting of metal materials is equipped with a tank with an annular channel for supplying water to the cutting zone, made in the form of a hollow cylinder, covering the nozzle with the nozzle, the diameters of the nozzle and the annular channel being the same.

This method is intended only for cutting metals and provides for the supply of water to the cutting zone, the flow rate of which is 0.01-4.0 ml / mm cut. This water flow provides an increase in cutting thickness at the same power. With an increase in water consumption, as the authors indicate, the cutting quality of steel parts deteriorates.

Cutting of composite materials requires a greater consumption of water, because water supply to the cutting zone is necessary to improve the quality of processing, namely, reducing the zone of possible thermal influence, which exceeds the cutting zone by 1.5-2 times. Moreover, it is necessary to completely remove the decay products of the cut to create environmentally friendly working conditions and efficient cooling of the edges of the part.

SUMMARY OF THE INVENTION

The objective of the invention is to develop technology to expand the technological capabilities of laser cutting of composite materials, namely, cutting large parts with complex spatial shape with high quality.

The problem is achieved in that in the method of laser cutting of composite materials, including supplying a laser beam to the surface to be treated, supplying the process gas coaxially with the laser beam, collimating the laser beam, deepening it into the workpiece and moving according to a predetermined program in the presence of a liquid medium, a liquid medium served on the surface of the workpiece in the form of a swirling jet coaxial to the laser beam in the zone of the alleged thermal influence of cutting.

In addition, the liquid medium is supplied in the form of a swirling jet with an initial diameter of 2-3 mm at a flow rate of 2.5-3.0 l / min.

And in the device for laser cutting of composite materials containing a laser cutting body having a focusing lens, a nozzle for supplying process gas, a nozzle nozzle and a cylindrical container with an annular channel for supplying a liquid medium,

the annular channel is equipped with a hollow conical nozzle, the inner surface of which is equipped with a swirling flow device.

Moreover, the flow swirling device is made in the form of grooves on the inner surface of the conical nozzle, inclined to its axis at an angle of 15-30 °.

This embodiment of the method and device allows for cutting parts of complex spatial configuration from composite materials with high quality.

List of drawings

The invention is illustrated by drawings, in which:

Figure 1 shows a schematic diagram of a device for implementing the proposed method of gas laser cutting.

Figure 2 shows a section of a conical nozzle with grooves.

Figure 3 shows a section (top view) of the cone nozzle.

The implementation of the invention

The method of gas-laser cutting of large-sized products from composite materials in accordance with the invention is as follows.

The workpiece 11 is installed in the pallet 5 on the conical pins 6.

A device for laser cutting of composite materials comprises a laser cutting case 3 having a focusing lens 2. A collimated laser beam 1 of a ytterbium fiber laser is supplied to the focusing lens 2 and is buried by 0.2-0.4 thicknesses in the material of the workpiece.

The laser cutter housing 3 also includes a nozzle 7 for supplying the process gas coaxially with the laser beam, a nozzle nozzle 8 with an outlet diameter of 1.5-2.0 mm for imparting a direction to the process gas coaxial with the laser beam, and a cylindrical container 9 with an annular channel 10 for supplying liquid medium (water) into the treatment zone.

The liquid used is industrial water, as it is transparent for a wavelength of λ = 1.07 μm and does not absorb laser radiation.

To impart turbulence to the fluid flow, the annular channel 10 is equipped with a hollow cone nozzle with an outlet diameter of 2.5-3.0 mm, and the diameter of the outlet is selected from the condition:

D≥t + t _HST , where t is the cut width, t _HST is the width of the heat affected zone.

The inner surface of the nozzle is equipped with a swirling flow device.

The device is made in the form of spiral grooves 4 on the inner surface of the conical nozzle, inclined to its axis at an angle of 15-30 °, which allows you to swirl the fluid flow in the treatment area and more intensively cool the edges of the cut, while reducing their carbonization.

To drain the spent liquid with decay products and its further disposal in the pan there is a drain hole.

The device operates as follows.

The ytterbium fiber laser is turned on from the remote control of the laser installation, the radiation of which is transported through the fiber cable to the cutting head, where it is first collimated, and then focused on the surface to be treated with a condenser lens 2, with a focus depth of 0.2-0.4 of the thickness of the processed product 11.

At the same time, according to the CNC program, a command is given to supply the process gas and coolant (water).

The liquid medium is fed to the surface of the workpiece in the form of a swirling jet coaxially with the laser beam in the zone of the alleged thermal influence of cutting. The fluid flow rate is determined by the thickness and type of the processed composite material. So for carbon plastics with a thickness of 3-4 mm, the water consumption during cutting is 2.5-3.0 l / min.

A command is also given to move the cutting head along a given contour.

Process gas (in our case, N ₂ ) at a pressure of 0.8 ÷ 1.4 MPa enters the cutting zone, mixing along the way with drops of liquid (water), and carries decay products from the cutting zone into the pan.

Liquid (water) is also supplied to the cutting zone under a pressure of 0.3 ÷ 0.5 MPa concentrically to the laser beam with a swirl, which allows the surface to be well protected from carbonization and to make the thermal influence zone minimal over the entire cutting depth.

An example of a specific implementation of the invention

For cutting large-sized products from composite material (for example, cutting holes in the noise absorption system of an engine nacelle, material thickness ~ 3 mm, product diameter ~ 1.5 m, height ~ 2 m), the LTK-3D 5-coordinate laser complex with ytterbium was used 2 kW fiber laser (LS-2) operating in a pulsed radiation mode. The size of the working area of the complex is 5000 × 3000 × 800 mm. A specially designed swivel head, mounted in the machine support, allows not only to move the cutting head in X, Y, Z coordinates, but also to rotate it relative to the vertical Z axis (coordinate C) n × 360 ° and rotate ± 120 ° around the horizontal axis ( coordinate B), which makes it possible to process the surface of the product of complex spatial shape.

The laser beam at the exit from the transported fiber cable was first collimated and then focused with a lens with F = 150 mm onto the surface to be processed with a focus depth of 0.2 thickness of the product. The diameter of the laser spot in the working zone was ~ 150 μm. The high power density of laser radiation allows you to destroy the fibers of the composite material with minimal roughness.

The simultaneous supply of a program gas to the cutting zone of the process gas (N ₂ ) under a pressure of 1.4 MPa coaxially with the laser beam and liquid (water) in the form of a swirling jet with an initial diameter of 2.5 mm under a pressure of 0.25 MPa coaxially with the beam allows protecting the thermal zone effects from carbonization and carry decay products from the cutting zone into the pallet.

The use of this technology makes working conditions more environmentally friendly, and the quality of the cut with a minimum heat-affected zone and uniform over the entire depth of the edge of the workpiece. All decay products settle to the bottom of the pallet.

The cutting speed was 1.5 ÷ 1.8 m / min. The heat-affected zone was ~ 0.15 mm, and carbonization was uniform over the entire surface of the cut. While cutting the same composite material without water supply leads to a zone of thermal influence at the inlet of the cut 0.25 mm, and at the outlet 0.4 mm. Moreover, the process conditions were accompanied by a strong gas contamination with a characteristic odor of processing composites.

Thus, the proposed method of gas-laser cutting of composite materials allows you to process products of large dimensions with good cut quality and creates more favorable working conditions.

Claims (4)

1. A method of laser cutting of composite materials, including supplying a laser beam to the surface to be treated, supplying a process gas coaxially with the laser beam, collimating the laser beam, deepening it into the workpiece and moving in accordance with a predetermined program in the presence of a liquid medium, characterized in that the liquid the medium is fed to the surface of the workpiece in the form of a swirling jet coaxially with the laser beam into the zone of the thermal effect of cutting. 2. The method of laser cutting of composite materials according to claim 1, characterized in that the liquid medium is supplied in the form of a swirling jet with an initial diameter of 2-3 mm at a flow rate of 2.5-3.0 l / min. 3. A device for laser cutting of composite materials, comprising a laser cutting housing having a focusing lens, a nozzle for supplying process gas, a nozzle nozzle and a cylindrical container with an annular channel for supplying a liquid medium, characterized in that twisting screws are made on the inner surface of the annular channel of the cylindrical container coolant flow spiral grooves. 4. The device for laser cutting of composite materials according to claim 3, characterized in that the spiral grooves on the inner surface of the channel are made with an inclination to its axis at an angle of 15-30 °.

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