RU2727392C1 - Optical head for laser cutting, welding - Google Patents

Abstract

FIELD: optics; technological processes.SUBSTANCE: invention relates to an optical head for processing materials by a laser beam, specifically to laser welding and cutting processes. Optical head comprises outer fixed housing (1) and inner movable housing (3). Cylindrical nozzle (4) is attached to inner movable housing (3), which moves downwards or upwards depending on machining mode by means of mechanical or electric drive (5). Focusing lens (6) is installed in cylindrical nozzle (4). On side surface of cylindrical nozzle (4) there are through holes (7) located under focusing lens (6). Along outer cylindrical nozzle (4) outer contour there are annular plates (8) and (9) enveloping it along circumference. Circular plates (8) and (9) simultaneously cover channel (10) of active or protective gas channel (11) and accordingly open or close channel (11) of protective or channel (10) of active gases. Movement of annular plates (8) and (9) is fixed by limiting rings (15) until it stops.EFFECT: optical head for laser cutting and welding is proposed.5 cl, 8 dwg

Description

The invention relates to the field of processing materials with a laser beam, namely, to the processes of laser welding, cutting, drilling holes.

Known optical head for laser cutting of sheet metal (patent RU No. 151792, IPC B23K 26/38, published on 20.04.2015), in which the unit for moving the focusing system along the optical axis relative to the telescopic system is made in the form of two cylinders interconnected by a threaded connection of different diameter with the ability to move relative to each other along the optical axis, while the focusing system is installed on the side of the free end of the cylinder of a smaller diameter, and the telescopic system is installed on the side of the free end of the second cylinder of a larger diameter, and the unit for simultaneous movement along the optical axis of the focusing and telescopic systems is made in the form of a cylinder with a thread on the outer surface, while a thread is made on the inner surface of the optical head housing, corresponding to the thread of the specified cylinder, and the cylinder itself is rigidly fixed on the outer side of the cylinder with the focusing system of the unit for moving the focusing systems along the optical axis relative to the telescopic system.

However, the known device does not provide sufficient precision in material processing and has a complex structure. This leads to a loss of time, low accuracy.

Known optical head for laser processing (patent RU No. 34427, IPC B23K 26/00, B23K 26/02, B23K 26/03, published 10.12.2003). The optical head for laser processing contains a device for outputting laser radiation from an optical fiber, a rotatable interference mirror, a telescopic system consisting of a negative component and a positive component, a focusing system, a visual observation system including a video camera optically coupled with a rotary interference mirror with a focusing system, and a monitor ... To control radiation between the device for outputting laser radiation and the focusing system, one of the optical elements of the telescopic system (for example, an optical element) is installed with the ability to move along its optical axis. The radiation output device, rotary interference mirror, telescopic system, focusing system, visual observation system are located in a single housing.

However, the known device does not provide for the implementation of various technological operations (cutting, welding, drilling holes) and has a complex structure.

Known optical laser head (patent RU No. 2578885, IPC B23K 26/14, published 03/27/2016), containing external and internal gas nozzles with channels for supplying active and protective gases, installed concentrically and with a gap, a focusing lens placed in the internal nozzle , and through holes made on the side surface of the inner nozzle. The inner nozzle is made like a Laval nozzle, and the focusing lens is placed in the inner nozzle to ensure that its cylindrical surface is located along the cylindrical surface of the inner nozzle with the ability to move along the axis, while the channel for supplying active gas to the inner nozzle is located between the focusing lens and the Laval nozzle, and the through holes in the inner nozzle are located above the lens. The optical laser head is equipped with locks with the ability to limit the movement of the focusing lens along the axis, located below the through holes and above the lower channel for supplying the process gas.

However, the known device does not provide sufficient accuracy of material processing due to piston movement of the nozzle, change of specialized optical heads for performing various technological operations (cutting, welding, drilling holes). This leads to loss of time, low accuracy and equipment downtime during its retooling.

Known laser optical head (patent RU No. 2641213, IPC B23K 26/14, published on January 16, 2018), the closest in technical essence and taken as a prototype, where the inner movable body with a nozzle is installed in a stationary outer body with the ability to move by means of a gear transmission made in the form of a toothed rack mounted on the inner casing and a pinion shaft mounted on a bracket fixed on the outer stationary casing and connected to an electric drive, and a capacitive sensor is installed in the lower part of the outer stationary casing to install and control the size between the nozzle exit and the processed part, and at the nozzle outlet there is a removable nozzle with a converging-expanding channel at the outlet. To ensure cutting, welding or punching of metal holes from 1 mm to 20 mm, a removable nozzle is made with a narrow section diameter of 0.2 ± 0.02 mm and an expansion angle of 30 °. To ensure cutting of metals from 20 mm to 40 mm, a removable nozzle is made with a diameter in a narrow section of 0.5 ± 0.02 mm and an expansion angle of 15 °.

However, the known device requires more equipment and maintenance personnel to operate. The presence of an electric motor for starting the movement of the inner movable body with an inner nozzle complicates the design of the laser head, somewhat increases the cost of the device and complicates its operation.

The technical problem to be solved by the claimed invention is the creation of an optical head, for using it for laser cutting, welding, as well as for drilling holes, when high technological indicators are achieved - the minimum cutting width and surface roughness, as well as the minimum heat-affected zone.

The technical result, which the present invention is aimed at, is to increase the processing accuracy, reduce energy consumption, simplify equipment, design reliability, and reduce the time for changing modes between cutting and welding.

The technical result is achieved by the fact that an optical head for laser cutting, welding, containing an outer stationary body with channels for supplying active or shielding gases, inside of which an inner movable body with a nozzle is arranged concentrically and with a gap with the ability to move along an axis, a focusing lens installed in a nozzle, on the lateral surface of which through holes are made, located under the focusing lens, and a removable nozzle is placed at the nozzle outlet, the novelty is that the nozzle body is cylindrical, while along its height there are two annular plates to block the active and protective gas supply channels when moving, there are sealing collars with a smooth surface on the outer end surfaces of the annular plates, and there are limit rings between the outer stationary body and the inner movable body.

The removable nozzle is made tapering.

The detachable nozzle is made converging-expanding.

Cuffs are made of a sealed structure with composite linings for optimal gliding.

A capacitive sensor is installed in the lower part of the outer stationary body to determine the distance between the cylindrical nozzle exit and the workpiece.

Figure 1 shows a longitudinal section of an optical head for laser cutting, welding in cutting mode and drilling holes.

FIG. 2 shows a longitudinal section of an optical head for laser cutting, welding in welding mode.

FIG. 3 - view And Fig. 1.

FIG. 4 - section b-b Fig. 1.

FIG. 5 - view D of FIG. 2.

FIG. 6 - section b-b of Fig. 1.

FIG. 7 is an enlarged view of D (Fig. 2) of a removable nozzle in the mode of cutting and drilling metal holes with a thickness of 1 mm to 40 mm.

FIG. 8 shows an enlarged view E (Fig. 1) of a removable nozzle in the mode of welding metals with a thickness of 1 mm to 10 mm.

The optical head for laser cutting, welding contains an outer fixed body 1, which is equipped with a cover 2 (Fig. 1 and Fig. 2). Inside the outer stationary body 1 there is an inner movable body 3 with a nozzle, the body of which is cylindrical (cylindrical nozzle) 4 with the ability to move down (Fig. 1) or up (Fig. 2) depending on the processing mode using a mechanical or electric drive 5 (Fig. 3). Figure 4 shows a section BB of the location of the mechanical or electrical drive 5 for driving (Fig. 4). A focusing lens 6 (Fig. 1 and Fig. 2) is installed in the cylindrical nozzle 4. On the side surface of the nozzle 4 there are through holes 7 located under the focusing lens 6 (Fig. 1 and Fig. 2). Along the height of the outer contour of the outer contour of the nozzle 4, there are annular plates 8 and 9, covering it around the circumference. The annular plates 8 and 9 are located relative to each other in such a way that they separate the active gas supply channel 10 and the protective gas supply channel 11. At the same time, the annular plates 8 and 9 overlap the active gas channel 10 or the protective gas channel 11 and, respectively, open or close the protective gas channel 11 or the active gas channel 10 when moving upward (Fig. 2) and down (Fig. 1) alternately, respectively.

During cutting or drilling holes, the inner movable body 3 with a cylindrical nozzle 4 and a focusing lens 6 moves downward to establish a predetermined (minimum) size of the focal spot (Fig. 1), while the annular plate 8 opens the channel 10 for supplying the active gas - oxygen, and the annular plate 9 closes the channel 11 for supplying a protective gas - nitrogen, argon or helium. A cavity 12 is formed, into which an active gas, oxygen, is supplied through channel 10. In the mode of cutting or drilling holes at the lower position of the cylindrical nozzle 4, the axes of the through holes 7 coincide with the axis of the channel 10 for supplying the active gas, and this axis becomes perpendicular to the axis of the laser beam. In the lower position of the cylindrical nozzle 4, the axis of the channel 10 for supplying the active gas is perpendicular to the axis of the laser beam (Fig. 1). In cutting modes and drilling holes, a converging-expanding removable nozzle 16 is attached to the cylindrical nozzle 4 (Figs. 1, 5), which for cutting metals with a thickness of 1 mm to 40 mm has a diameter in a narrow section of 0.5 ± 0.02 mm and expansion angle 15 ° (fig. 7).

In welding mode, the inner movable body 3 with a cylindrical nozzle 4 and a focusing lens 6 moves upward to establish a given (maximum) size of the focal spot (Fig. 2), while the annular plate 9 opens the channel 11 for supplying a protective gas - nitrogen, argon or helium , and the annular plate 8 closes the channel 10 for supplying the active gas - oxygen. A cavity 13 is formed, into which a protective gas - nitrogen, argon or helium - is supplied through channel 11. In the welding mode, a converging removable nozzle 17 is attached to the cylindrical nozzle 4 (Figs. 2, 5), which for welding metals with a thickness of 1 mm to 10 mm has a diameter in a narrow section of 1 ± 0.02 mm (Fig. 8). This feature during welding at subsonic speed will simultaneously cleanse the metal processing area from slags and improve the quality of welding, increase the strength of the workpieces 19.

On the outer end surfaces of the annular plates 8 and 9, cuffs 14 with a smooth surface, with a sealed structure and with composite linings are inserted, providing optimal sliding and tightly fitting to the inner surface of the outer stationary body 1. Cuffs 14 ensure the seal of the annular plates 8 and 9 along the inner surface the outer stationary body 1. The movement of the annular plates 8 and 9 is fixed by the limit rings 15 to the stop (Fig. 6). The cuffs 14 provide a hermetic overlap of the corresponding channel 10 with the active or channel 11 with the protective gas, therefore, 100% of the active or protective gases are supplied to the corresponding channel.

On the outer stationary body 1, a capacitive sensor 18 is rigidly fixed (Fig. 1 and Fig. 2) to determine the distance between the cut of the cylindrical nozzle 4 and the workpiece 19, which is mounted on the bracket 20 in the lower part of the outer stationary body 1, which ensures the operability of the optical head ... For fastening removable nozzles 16 and 17 with screws with a diameter of 3 mm (Fig. 1) there is a key hole 21 (Fig. 5). A laser beam enters the area of the laser cut 22 (Fig. 1) or weld 23 (Fig. 2) through the focusing lens 6.

Optical head for laser cutting, welding works as follows.

When cutting and drilling holes in metals with a thickness of 1 mm to 40 mm, a converging-expanding removable nozzle 16 is installed in the cylindrical nozzle 4, in which the flow rate of the gas jet is supersonic, which will simultaneously clean the material processing site from slags and improve the processing quality. To achieve the smallest focal spot size when performing cutting or drilling modes, the inner movable body 3 with a cylindrical nozzle 4 is moved downward by a mechanical or electric drive 5 until it stops by restricting rings 15, while the axis of the channel 10 through which the active gas - oxygen is fed into the cavity 12 is located perpendicular to the axis of the laser beam and, therefore, perpendicular to the axis of the cylindrical nozzle 4. Next, oxygen passes through the through holes 7 of the cylindrical nozzle 4 and together with the laser beam through the focusing lens 6 enters the laser beam coaxially into the laser cut zone 22 (Fig. 1). The annular plate 8 opens the channel 10 for supplying the active gas - oxygen (Fig. 1), and the annular plate 9 closes the channel 11 for supplying the protective gas - nitrogen, argon or helium. At the same time, under the action of excess pressure in the cavity 12 of the outer stationary body 1, the movement of the inner movable body 3 with the cylindrical nozzle 4 downward occurs until the movable arm 24, on which the movable body 3 is fixed (Fig. 1), touches the limit ring 15 acting as a stop. A supersonic jet, blown into the laser cut zone 22 through a converging-expanding nozzle 16, removes the resulting metal melt from a narrow laser cut 22 (b = 0.1-0.35 mm) with high efficiency, which makes it possible to cut metals of large thicknesses up to 40mm with high cutting speed, which will generally improve the productivity of the laser cutting mode.

In the mode of drilling metal holes from 1 mm to 40 mm, the process proceeds similarly to the mode of laser cutting of metals from 1 mm to 40 mm, but in addition, a high power of laser radiation is required.

When switching to the welding mode, it is necessary to replace the converging-expanding removable nozzle 16 with a converging removable nozzle 17 for welding metals with a thickness of 1 mm to 10 mm. Removing the optical head to a free space from the workpiece 19, the operator makes a special tool to change the converging-expanding removable nozzle 16 to the converging removable nozzle 17. The removable nozzles 16, 17 are fixed on the cylindrical nozzle 4. The movement of the inner movable body 3 with the cylindrical nozzle 4 is directed upwards (Fig. 2) to achieve the required increased size of the focal spot, while the annular plate 9 opens the channel 11 for supplying a protective gas - nitrogen, argon or helium, and the annular plate 8 closes the channel 10 for supplying the active gas - oxygen. The workpiece 19 (Fig. 2) is supplied with a protective gas - nitrogen, argon or helium through the channel 11 of the outer stationary body 1 (Fig. 2), which enters the cavity 13. The shielding gas is supplied simultaneously with the laser beam to the weld zone 23 and protects it from splashes and environmental influences (Fig. 2). In the mode of welding metals with a thickness of 1 mm to 10 mm, the intensity of the laser beam is set depending on the mode being performed.

As a result of experiments carried out at PJSC "KAI-Laser", the following indicators were obtained: the roughness of the cut surface on titanium alloys is not higher than 2 ... 6 microns, on stainless and high-alloy steels not higher than 10 ... 28 microns with a cut width of 0.1 ... 0, 35 mm, the depth of the heat-affected zone is not more than 0.2 mm.

Technological characteristics of "Optical head for laser cutting, welding":

Process gas pressure, MPa up to 2.5 Process overpressure gas on focusing optics, MPa no more than 0.02 Laser power, kW 0.1 ... 30 Aperture angle of laser radiation, ° С 2 ... 30 Saving process gas consumption,% up to 70

For welding, the optical head will provide the main technological indicators at the optimal level: the width of the weld seam is from 0.1 mm to 5 mm on metals with a thickness of 1 mm to 10 mm, the heat affected zone near the weld seam is from 0.015 mm to 0.15 mm.

The optical head for laser cutting, welding will allow for precision welding of metals with a thickness of 1 mm to 10 mm, cutting and drilling of metal holes with a thickness of 1 mm to 40 mm with high productivity, provided by changing modes during processing and displacement of the inner movable body 3 with a cylindrical nozzle 4 up or down until it stops. Process gases (active or shielding) in the zone of laser cutting 22, welding, drilling holes are supplied alternately, depending on the required operation.

The offered optical head is universal, it allows to carry out the following modes: laser cutting, welding and drilling of holes and to quickly reset the preset modes, which reduces energy consumption, and also ensures the quality of laser cut, strength and reliability of the weld.

Claims (5)

1. An optical head for laser cutting or welding, containing an outer stationary housing with channels for supplying active or shielding gases, inside which an inner movable body with a nozzle is located concentrically with a gap and with the possibility of movement along the axis, a focusing lens installed in the nozzle on the side the surface of which there are through holes located under the focusing lens, and a removable nozzle is located at the nozzle outlet, characterized in that the nozzle body is cylindrical, while along its height there are two annular plates to block the active and protective gas supply channels during movement, while on the outer end surfaces of the annular plates there are sealing collars with a smooth surface, and there are limit rings between the outer stationary body and the inner movable body. 2. The optical head of claim. 1, characterized in that the removable nozzle is made tapering. 3. Optical head according to claim 1, characterized in that the detachable attachment is converging-expanding. 4. Optical head according to claim. 1, characterized in that the cuffs are made of a sealed structure with composite linings that provide optimal gliding. 5. An optical head according to claim 1, characterized in that a capacitive sensor is installed in the lower part of the outer fixed body to determine the distance between the cylindrical nozzle cut and the workpiece.

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