RU2382693C1 - Method of gas-laser cutting of composite materials - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: method includes feeding of laser beam on treated surface, feeding co-axially to laser beam of process gas, collimation of laser beam, its embedding into treated product and movement by specified program. Cutting is implemented in liquid field. Product is located in bath with water on cone-shaped pins with exceeding of water level over surface of product equal to 10-15 mm. Cutting is implemented by ytterbium laser with laser beam embedding into treated product for 0.2-0.4 of its thickness. Movement of laser beam is implemented at a rate 1.2-1.8 m/min.

EFFECT: enhancement of manufacturing capabilities and improvement of ecology at treatment of composite materials and it is provided high quality of cutting.

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Description

Technical field

The invention relates to technological processes, namely to laser processing of materials, in particular to gas-laser cutting of composite materials, and can be used in the manufacture of parts from composite materials to improve their quality.

State of the art

A known method of cutting epoxy carbon fiber from carbon fibers in epoxy resin with a laser based on non-aluminum yttrium garnet (Nd, YAG) with limited diffraction, which operates in Q-switching mode with high maximum power at high pulse speeds (see US patent No. 5500505, class IPC B23K 26/00, 1996). The fibrous composite material is cut with a minimum heat affected zone. The selective and increased wavelength process is used to increase the efficiency of bonding with the components of a composite of epoxy carbon material.

The main disadvantage of this method is the dispersion of the radiation of the 1st, 2nd and 3rd harmonics in power and, accordingly, the growth of its unproductive losses, as well as the complicated design of the laser itself due to the harmonics extraction device.

A known method of laser cutting of sheet material, especially for laser cutting of composites (US patent No. 4639572, class IPC B23K 26/00, 1987). An inert gas screen is used, preferably nitrogen. The inert gas screen acts on both sides of the sheet. At the same time, a cylindrical inert gas jet is directed to the surface of the sheet, to which the laser beam is directed and coaxially with it, and a cylindrical inert gas jet directed to the other side, act together to create a gas screen, which helps to minimize the carbonization of the edges on the material being cut.

The disadvantage of this method of laser cutting of composite materials is its limited use - only for sheet material, as well as the removal of decay products from the cutting zone.

A known method of dimensional processing of composite products in the manufacture of complex products (RF patent No. 2219029, class IPC B23K 26/38, 2003). A complex mode is used as the mode composition of the radiation. The focus of the beam is directed inside the material at a distance from the surface within 1 / 2-5 / 8 of the thickness. The radiation power is maintained in the range of 500-700 watts. The speed of the beam is in the range of 0.8-2.5 cm / s. This allows you to get high quality cuts on the upper and lower surfaces of the material with a minimum zone of thermal influence.

The main disadvantage of this method is the inability to prevent oxidation of the lower edge of the cut, which leads to uneven carbonization of the cut edge, as well as the removal of decay products from the cutting zone, which greatly pollutes the environment and worsens the environmental working conditions.

There is a method of gas-laser cutting of composite materials, which includes supplying process gas under pressure to the torch body coaxially with the laser beam and additionally supply water at a flow rate of 0.01-4.0 ml / mm cut (RF patent 2089365). The invention in terms of the device consists in the fact that the device comprises a torch body with a condenser lens, a hole for supplying process gas and a nozzle with an injection-type nozzle. In addition, it is additionally equipped with a tank for supplying water to the cutting zone. The invention allows to increase the thickness of the cut materials without increasing energy costs and to improve the quality of the cut by reducing the zone of thermal influence.

However, the water jet makes it difficult to control the cutting process and does not provide an adequate cooling zone on the workpiece, which makes the quality of the cut not satisfactory.

SUMMARY OF THE INVENTION

The objective of the invention is the development of such a process gas cutting, which would expand the technological capabilities and improve the environment when processing composite materials. Moreover, the method should provide high quality cutting of products from composite materials and improve working conditions.

The problem is achieved in that in the method of gas-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 given program, cutting is performed in a liquid medium, for example industrial water.

Moreover, cutting is performed with an ytterbium laser with a laser beam being deepened into the workpiece by 0.2-0.4 of its thickness, and the laser beam is moved at a speed of 1.2-1.8 m / min.

This embodiment of gas-laser cutting allows expanding the technological capabilities of the composite materials process: providing the possibility of gas-laser cutting of composite materials of complex spatial shapes with improving the quality of cutting edges of the material being cut, and improving the ecology of working conditions.

The drawing shows a schematic diagram of a device for implementing the proposed method of gas laser cutting in a liquid medium.

The implementation of the invention

The method of gas laser cutting of composite materials in accordance with the invention is as follows.

The processed product from composite materials (KM) is placed in a liquid medium. Industrial liquid is used as a liquid, since it is transparent for a wavelength of λ = 1.07 μm and does not absorb laser radiation. The water level must exceed the highest point of the workpiece by 10-15 mm.

After installing the CM product in a liquid medium, a ytterbium fiber laser beam is supplied to the part. The beam is focused by a capacitor lens on the surface to be treated with a focus deepening by 0.2-0.4 thickness of the workpiece 4 (see drawing). After that, the part is cut in a liquid medium as follows: at the point where the beam is located, the material burns out, then the laser beam is moved along a predetermined path using a control program at a speed of 1.2-1.8 m / min. Co-axially with the beam, process gas N _{2 is} supplied at a pressure of ≤1 MPa, where it with radiation enters the product 4 into the cutting zone, mixing along the way with drops of liquid. Further, the process gas carries decay products from the cutting zone. The decay products fall into the lower part of the liquid bath 5. Due to the use of a liquid medium, the decay products are removed from the cutting zone, the heat-affected zone is reduced by approximately 2 times, and carbonization of the edges occurs evenly.

Cutting is carried out on a laser technological complex using an ytterbium fiber laser and a liquid medium.

The radiation of the ytterbium fiber laser 1 is transported to the body of the optical torch 3, where it is focused (collimated) by a capacitor lens 2. The process gas N ₂ is supplied under pressure ≤1 MPa to the torch body 3, where it is coaxially with the radiation supplied to the product 4.

Cutting is carried out in a container 7, which is installed in a technological complex in the zone of operation of an ytterbium fiber laser.

The level of the liquid medium 5 should be 10-15 mm higher than the height of the maximum point of the workpiece, and the product itself is mounted on the cone pins 6, which allow the decay products carried out from the cutting zone by process gas to settle to the bottom of the bathtub. The tank 7 is equipped with a device for supplying water (not shown in the drawing) and a device for draining water 8. The level in the tank is regulated by the supply and discharge of water and is set depending on the geometric dimensions of the product. The liquid from the bath is periodically drained as it becomes dirty through the drain located in the bottom of the bath, and the accumulated decomposition products are removed from the bath.

An example of a specific implementation of the invention.

The work was carried out on a laser technological complex equipped with a 2 kW ytterbium fiber laser in a pulsed radiation mode and a specially developed rotary head that allows you to move the optical cutter in 3 coordinates, as well as rotate about the vertical Z axis (coordinate C) and rotate ± 135 ° С around horizontal axis (coordinate B), which made it possible to maintain the optical cutter all the time in a perpendicular position to the machined three-dimensional surface of a complex spatial product .

The laser beam from the transported fiber cable was first collimated, and then focused by a lens 2 with a focal length of 150 mm onto the surface to be processed with a focus deepening by 1/3 of the thickness of the product from the upper surface. The diameter of the laser spot in the focal plane was 0.15 mm. The high density of laser radiation allows to destroy carbon fibers with minimal roughness.

Cutting speed ~ 1.5 m / min.

The pressure of the process gas (N ₂ ) in the nozzle is 0.8 MPa.

Carbon fiber was cut with a thickness of 3 mm.

The heat affected zone was 0.1–4–0.15 mm, and carbonization was uniform over the entire surface of the cut.

All decay products settle to the bottom of the bath.

An example of the implementation of laser cutting without a liquid medium.

They made cutting at the same parameters without a liquid medium. The heat affected zone was 0.2–0.3 mm, and carbonization closer to the bottom surface was maximum. The smoke of decay products instantly filled the entire working area, which complicated the processing process.

Thus, the proposed method of gas-laser cutting of composite materials using a liquid medium, unlike the known one (with an inert gas screen), makes it more intensified and provides the following advantages:

- allows you to cut not only a flat product, but also a complex spatial shape;

- helps to reduce the zone of thermal influence due to more intensive cooling of the cut zone and isolation of both surfaces from the oxidizing medium;

- creates environmentally friendly working conditions;

- allows to increase the processing speed due to the intensification of the cutting process when droplets of liquid along with the process gas get into the cutting zone.

Claims (1)

A method of gas-laser cutting of products from composite materials, including supplying a laser beam to the surface of the product, 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, characterized in that the cutting is carried out with an ytterbium laser with deepening the beam into the workpiece by 0.2-0.4 of its thickness and with a speed of its movement of 1.2-1.8 m / min in a liquid medium, for which the product is placed in a bath of water on cone-shaped pins with excess water level above the surface of the product, equal to 10-15 mm

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