CN113560733B

CN113560733B - Laser-plasma composite cutting method and device

Info

Publication number: CN113560733B
Application number: CN202111045316.9A
Authority: CN
Inventors: 哈斯金·弗拉基斯拉夫; 蔡得涛; 郭瑞·弗拉基米尔; 王昕昕; 巴比奇·亚历山大; 怀玺; 舍甫琴科·维塔利; 张宇鹏; 罗子艺; 韩善果; 薛亚飞
Original assignee: China Uzbekistan Welding Research Institute of Guangdong Academy of Sciences
Current assignee: China Uzbekistan Welding Research Institute of Guangdong Academy of Sciences
Priority date: 2021-09-07
Filing date: 2021-09-07
Publication date: 2022-04-08
Anticipated expiration: 2041-09-07
Also published as: CN113560733A

Abstract

The invention relates to the technical field of welding or cutting, and provides a laser-plasma composite cutting method and device. The cutting method comprises the following steps: in the cutting direction, the front end face of the arc generated by the ring electrode and the front end face of the laser beam passing through the ring electrode are made to intersect. A cutting device, comprising: the laser comprises a nozzle, a ring electrode and a laser, wherein the nozzle is provided with an emergent hole, the nozzle is arranged on one side close to an arc starting end of the ring electrode, the arc starting end faces the emergent hole, the laser is arranged on one side of the ring electrode, which is far away from the nozzle, and the laser emission direction of the laser faces the emergent hole and is inclined relative to the extending direction of the emergent hole. According to the technical scheme, the problem of low composite energy efficiency in the composite heat source cutting process can be solved, and compared with other conditions, the cutting speed of the metal plate can be improved by about 30-40% by the aid of the method.

Description

Laser-plasma composite cutting method and device

Technical Field

The invention relates to the technical field of welding or cutting, in particular to a laser-plasma composite cutting method and device.

Background

With the deepening of the industrialization process, the deep research of the country in the fields of equipment, ocean, rail transit, new energy, metallurgy, aerospace and the like improves the process level of the fields of machinery manufacturing, ship manufacturing, energy and other industries, and the requirement of the advanced manufacturing process of large-scale welded structural parts further improves. These advanced manufacturing techniques further increase the demands on welding and cutting techniques. In the ship construction process, the efficient quality cutting and welding of steel and alloy with the thickness of 5-30mm are the most important construction requirements, the laser cutting and welding cost of the plate with the thickness range is very high at present, and the plasma cutting is difficult to meet the quality requirement that subsequent machining is not needed to a great extent. The method for cutting by adopting the laser and plasma composite heat source can solve the contradiction problem of cost and quality. In the prior art, a laser-plasma composite cutting method formed by forming an annular laser beam outside a tungsten electrode or introducing two laser beams outside the tungsten electrode is provided in a method and a device for carrying out plasma cutting or plasma welding under the support of laser, but the invention has the defects that the annular laser beam is diffused outwards, the laser energy density is reduced, and simultaneously, the plasma compressibility is reduced because a laser channel is reserved in an electrode, so that the advantages of the two parts cannot be well utilized. The invention patent 'method and device for processing workpiece by using laser equipment and arc equipment' adopts a compound mode of ring electrode and intermediate laser, as shown in figure 1, the principle is as follows: the laser beam 13 penetrates through the annular electrode 12, the annular electrode 12 ionizes plasma gas 17 to generate plasma 14, and the plasma 14 is focused on a workpiece through the nozzle 11 to form a composite heat source, at the moment, a first end face 141 and a second end face 131 of two approximately parallel end faces are formed on the end face before cutting, and efficient cutting cannot be realized by utilizing the composite heat source; the method also has the defects that overheating is easily caused on the parallel end face of the cathode, and in addition, the laser beam and the plasma arc with symmetrical axes have the problem of low recombination efficiency.

Therefore, the prior art lacks an effective laser-plasma hybrid method for cutting a workpiece.

In view of this, the invention is particularly proposed.

Disclosure of Invention

The object of the present invention includes, for example, providing a laser-plasma hybrid cutting method and apparatus which aim to ameliorate at least one of the problems mentioned in the background.

Embodiments of the invention may be implemented as follows:

in a first aspect, the present invention provides a laser-plasma hybrid cutting method, including:

in the cutting direction, the front end face of the arc generated by the ring electrode and the front end face of the laser beam passing through the ring electrode are made to intersect.

In an alternative embodiment, the ring electrode has a ring-shaped tip region, which is an arcing end.

In an alternative embodiment, the included angle between the axis of the exit hole of the nozzle and the central line of the laser beam is 5-10 degrees.

In an optional embodiment, during cutting, the included angle between the central line of the laser beam and the surface of the workpiece to be welded is 70-85 degrees.

In an alternative embodiment, the plasma gas used in the cutting is at least one of inert gases;

preferably, the cutting process adopts a method that the protective gas is introduced into the cutting device together with the plasma gas, and the protective gas comprises at least one of oxygen and air; more preferably, the shielding gas further comprises water vapor;

preferably, the plasma gas used for cutting is argon.

In an optional embodiment, a pulse mode or a continuous mode is adopted during cutting, and during the pulse mode, the laser pulse frequency range is 5-250 Hz, and the plasma pulse frequency range is 5-500 Hz.

In an alternative embodiment, the pulsed mode cutting is performed with one laser pulse and one plasma pulse, or one laser pulse and two plasma pulses as periods that are modulated in coordination.

In an optional embodiment, in the plasma pulse mode, supplementary pulse modulation with the frequency of 10-40 kHz is independently performed in each plasma pulse mode.

In an optional embodiment, the movement of the electric arc and the laser beam in the Z axis is relatively independent, and the position of a laser focus is dynamically adjusted within a range of 0-90% of the surface of the workpiece according to the thickness of the workpiece in the cutting process.

In a second aspect, the present invention provides a laser-plasma composite cutting apparatus comprising: the laser comprises a nozzle, a ring electrode and a laser, wherein the nozzle is provided with an emergent hole, the nozzle is arranged on one side close to an arc starting end of the ring electrode, the arc starting end faces the emergent hole, the laser is arranged on one side of the ring electrode, which is far away from the nozzle, and the laser emission direction of the laser faces the emergent hole and is inclined relative to the extending direction of the emergent hole.

In an alternative embodiment, the exit aperture of the nozzle has a diameter of 2-6 mm.

The beneficial effects of the embodiment of the invention include, for example:

when cutting, the front end face of the arc generated by the ring electrode and the front end face of the laser beam passing through the ring electrode are made to intersect in the cutting direction. The intersection of the two heat source end surfaces is used as a main cutting action part, the optimal space layout is formed in the cutting process, the problem of low composite energy efficiency in the composite heat source cutting process can be solved, and compared with other conditions, the cutting speed of the metal plate can be improved by about 30-40%. Meanwhile, on the premise of the same energy consumption, the thickness of the cuttable workpiece is increased, the service life of the cathode is prolonged, and the cutting gun is protected from being damaged due to reflection of the laser beam.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic diagram of a conventional laser-plasma hybrid cutting method;

FIG. 2 is a schematic diagram of a cutting apparatus and method according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram illustrating the specific arrangement of the apparatus and the workpiece when the apparatus and the method for cutting a workpiece according to an embodiment of the present application cut the workpiece;

FIG. 4 is a schematic view of cut surfaces after cutting according to the methods provided in example 1 and comparative example 1 in the experimental example;

fig. 5 is a schematic view of cut surfaces after cutting according to the methods provided in example 2 and comparative example 2 in the experimental example.

Icon: 11-a nozzle; 111-exit aperture; 12-a ring electrode; 121-arcing end; 13-a laser beam; 131-a second front end face; 14-an electric arc; 141-a first front face; 16-intersecting surfaces; 17-plasma gas; 20-workpiece.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or a positional relationship based on that shown in the drawings or that the product of the present invention is used as it is, this is only for convenience of description and simplification of the description, and it does not indicate or imply that the device or the element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

Referring to fig. 2, the present embodiment provides a laser-plasma composite cutting apparatus, which includes: the laser comprises a nozzle 11, a ring electrode 12 and a laser, wherein the nozzle 11 is provided with an exit hole 111, the nozzle 11 is arranged on one side close to an arc starting end 121 of the ring electrode 12, the arc starting end 121 faces the exit hole 111, the laser is arranged on one side of the ring electrode 12 away from the nozzle 11, and the laser emission direction of the laser faces the exit hole 111 and is inclined relative to the extending direction of the exit hole 111.

When cutting, the ring electrode 12 and the laser are electrified, the laser beam 13 passes through the middle part of the ring electrode 12 and the exit hole 111 in sequence, the plasma gas 17 passes through the middle part of the ring electrode 12 and enters the exit hole 111, when the plasma gas 17 passes the arcing end 121 of the ring electrode 12, an arc 14 is formed, the particular arrangement of the laser and the exit aperture 111 being such that the laser beam 13 is emitted as close as possible to the arc 14 for eventual intersection, cutting is performed with a direction from a side where the laser beam 13 and the arc 14 do not intersect to a side where the laser beam 13 and the arc 14 intersect as a proceeding direction, and thus, an intersection of two heat source end faces serves as a cutting main acting portion, the optimal space layout is formed in the cutting process, the problem of low composite energy efficiency in the composite heat source cutting process can be improved, compared with other cases, the proposed method can improve the cutting speed of the metal plate material by about 30-40%. Meanwhile, on the premise of the same energy consumption, the thickness of the cuttable workpiece 20 is increased, the service life of the cathode is prolonged, and the cutting gun is protected from being damaged due to reflection of the laser beam 13.

Preferably, the ring electrode 12 has a ring-shaped tip portion, which is an arcing end 121. The arrangement is favorable for the discharge of the electrode at the point, the energy is concentrated, the integral overheating is not easy to cause, the service life of the electrode is prolonged, and the problems that the annular electrode 12 is easy to cause overheating at the parallel end surface of the cathode and the laser beam 13 and the plasma arc 14 of the symmetrical axis have low composite efficiency can be solved.

Preferably, the nozzle 11, the annular electrode 12 and the laser are coaxially arranged, the exit hole 111 of the nozzle 11 is inclined relative to the axis of the nozzle 11, that is, the exit hole 111 is an inclined hole, and the angle α between the axis of the nozzle 11 and the center line of the exit hole 111 is 5-10^°。

The arrangement is different from the symmetrical structure of the conventional exit hole 111, and the center of the nozzle 11 is arranged in an asymmetrical structure, so that the laser beam 13 can be superposed with the front end of the plasma beam (arc 14), and the energy efficiency is maximized at the position. At this time, the axis of the laser beam 13 forms an angle of 70-85 degrees with the workpiece 20, and damage to the gun head caused by reflected light or other substances directly entering the cutting head during cutting is avoided.

Preferably, nozzles of different exit aperture 111 diameters are selected according to the arc 14 compressibility requirements, the exit aperture 111 diameter being in the range of 2-6 mm. At this time, since the nozzle 11 is at the outermost layer of the tip end, replacement is easily achieved.

The laser-plasma composite cutting method provided by the embodiment of the application comprises the following steps:

in the cutting direction, the front end face (first front end face 141) of the arc 14 generated by the ring electrode 12 and the front end face (second front end face 131) of the laser beam 13 passing through the ring electrode 12 are made to intersect.

The cutting end faces of the two heat sources are intersected, the intersection position of the two heat source end faces is used as a main cutting action position, the optimal space layout is formed in the cutting process, and the problem of low composite energy efficiency in the composite heat source cutting process can be solved.

Preferably, as shown in the figure, the included angle α between the axis of the plasma gas 17 (i.e. the central line of the exit hole 111) and the central line of the laser beam 13 (i.e. the central line of the nozzle 11) is 5-10 ° (e.g. 5 °, 7 °, 9 ° or 10 °) so as to ensure that the cutting end face of the arc 14 and the cutting end face of the laser beam 13 are close to each other, and further enable the energy efficiency of the composite heat source to be higher.

Further, in order to ensure better heat source utilization rate and cutting effect, during actual cutting, an included angle beta between the workpiece 20 and the central line of the laser beam 13 is 70-85 degrees, namely the laser beam 13 is inclined relative to a vertical surface, so that an intersecting surface 16 passing through the intersection of two heat source end surfaces and positioned between the two end surfaces can be almost perpendicular to the workpiece 20, and the purpose of aligning the main cutting action part with the workpiece 20 is achieved.

Preferably, the plasma gas 17 used in the cutting is at least one of inert gases, such as: argon, helium, and the like.

Preferably, the cutting process adopts a protective gas which is introduced into the cutting device together with the plasma gas 17, wherein the protective gas comprises at least one of oxygen and air; more preferably, the shielding gas further comprises water vapor or nitrogen.

The introduced oxygen is taken as combustion-supporting gas, the introduced water vapor has the function of water curtain protection, and the introduced nitrogen does not generate an oxide layer, so that the cutting quality is improved.

Further, the laser and plasma heat source modes can be selected from a pulse mode or a continuous mode according to the thickness and the material of the cut workpiece 20, and during the pulse mode, the laser pulse frequency range is 5-250 Hz, and the plasma pulse frequency range is 5-500 Hz.

Preferably, the pulsed mode cutting is performed by a laser pulse and a plasma pulse, or a laser pulse and two plasma pulses as periods in cooperation. The period is set in such a way, so that the requirements of cutting different thicknesses and materials on heat can be realized.

More preferably, when using plasma pulsing modes, supplemental pulsing at a frequency of 10-40 kHz is performed separately for each plasma pulsing mode in order to further compress the arc 14.

Further, the arc 14 and the laser beam 13 move relatively independently in the Z-axis, and the cutting process dynamically adjusts the laser focus position within a range of 0-90% of the surface of the workpiece 20 according to the thickness of the workpiece 20. Such an arrangement may make the cutting more efficient.

Example 1

The laser-plasma composite cutting method provided by the embodiment specifically comprises the following steps:

as shown in FIG. 3, the continuous cutting mode is adopted, a 4.0kW laser beam 13 and 200A plasma current are used for cutting 20mm Q235 steel, the cutting speed is 80m/h, the diameter of an emergent hole 111 of a nozzle 11 is 2mm, the laser focus is-5 mm, the plasma gas 17 is argon, the protective gas introduced together with the plasma gas 17 is argon, the gas flow rate is 150L/min, and the cutting gas pressure is 0.4 MPa. Alpha is 5 deg. and beta is 80 deg..

Example 2

As shown in FIG. 3, a continuous mode cutting was performed, in which 2.0kW laser beam 13 and 100A plasma were used to cut 10mm SUS304 steel at a cutting speed of 70m/h, the diameter of the exit hole 111 was 2mm using the nozzle 11, the laser focus was-3 mm, the plasma gas 17 was argon, the gas flow rate was 20L/min, the shielding gas introduced together with the plasma gas 17 was nitrogen, the gas flow rate was 160L/min, and the cutting gas pressure was 0.5 MPa. Alpha is 5 deg. and beta is 85 deg..

Example 3

This example is substantially the same as example 1 except that pulse mode cutting is employed, the period is one laser pulse and one plasma pulse, the laser frequency is 100Hz, and the plasma pulse frequency is 100 Hz.

Comparative example 1

This comparative example is essentially the same as example 1 except that:

cutting is carried out by the existing cutting method shown in figure 1, and the cutting speed is 60 m/h.

Comparative example 2

This comparative example is essentially the same as example 2, except that:

cutting is carried out by the existing cutting method shown in figure 1, and the cutting speed is 50 m/h.

Examples of the experiments

Cutting was performed according to the methods provided in examples 1 and 2 and comparative examples 1 and 2, and the cutting condition of the corresponding workpiece 20 was observed. The cut surface of comparative example 1 is shown in fig. 4 a, and the cut surface of example 1 after cutting is shown in fig. 4 b; the cut surface after cutting of comparative example 2 is shown as a in fig. 5, and the cut surface after cutting of example 2 is shown as b in fig. 5.

As can be seen from comparison of example 1 with comparative example 1, even though comparative example 1 reduced the cutting speed, the cut surface roughness after cutting was still inferior to that of example 1; as can be seen from comparison of example 2 with comparative example 2, even though comparative example 2 reduced the cutting speed, the cut surface roughness after cutting was still inferior to example 2. The two groups of comparison can show that the cutting method and the cutting device provided by the invention can improve the cutting speed and the cutting quality.

In summary, the laser-plasma combined cutting method and apparatus provided by the present invention intersect the front end surface of the arc 14 generated by the ring electrode 12 and the front end surface of the laser beam 13 passing through the ring electrode 12 in the cutting direction during cutting. The intersection of the two heat source end surfaces is used as a main cutting action part, the optimal space layout is formed in the cutting process, the problem of low composite energy efficiency in the composite heat source cutting process can be solved, and compared with other conditions, the cutting speed of the metal plate can be improved by about 30-40%. Meanwhile, on the premise of the same energy consumption, the thickness of the cuttable workpiece 20 is increased, the service life of the cathode is prolonged, and the cutting gun is protected from being damaged due to reflection of the laser beam 13.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A laser-plasma hybrid cutting method, comprising:

intersecting, in a cutting direction, a front end face of an arc generated by a ring electrode and a front end face of a laser beam passing through the ring electrode; the included angle between the axis of the emergent hole of the nozzle and the central line of the laser beam is 5-10^°When cutting, the included angle between the central line of the laser beam and the surface of the workpiece to be welded is 70-85 DEG^°。

2. The laser-plasma hybrid cutting method according to claim 1, wherein the ring electrode has a ring-shaped tip portion, and the ring-shaped tip portion is an arc start end.

3. The laser-plasma hybrid cutting method according to claim 1, wherein the plasma gas used for cutting is at least one of inert gases.

4. The laser-plasma hybrid cutting method according to claim 3, wherein a shielding gas is introduced into the cutting device together with the plasma gas during the cutting process, and the shielding gas comprises at least one of oxygen and air.

5. The laser-plasma hybrid cutting method according to claim 4, wherein the shielding gas further comprises water vapor or nitrogen gas.

6. The laser-plasma hybrid cutting method according to claim 3, wherein the plasma gas used for cutting is argon gas.

7. The laser-plasma hybrid cutting method according to claim 1, wherein a pulse mode or a continuous mode is adopted during cutting, wherein in the pulse mode, the laser pulse frequency ranges from 5 Hz to 250Hz, and the plasma pulse frequency ranges from 5 Hz to 500 Hz.

8. The laser-plasma hybrid cutting method according to claim 7, wherein the pulse mode cutting is performed by performing a cooperative modulation with one laser pulse and one plasma pulse, or one laser pulse and two plasma pulses as a period.

9. The laser-plasma hybrid cutting method according to claim 8, wherein in the plasma pulse mode, complementary pulse modulation with a frequency of 10 to 40kHz is independently performed in each plasma pulse mode.

10. The laser-plasma hybrid cutting method according to claim 1, wherein the arc and the laser beam are moved relatively independently in the Z-axis, and the cutting process dynamically adjusts the laser focus position in a range of 0-90% from the surface of the workpiece according to the thickness of the workpiece.