CN116944684A - laser-CMT efficient welding method and device for sheet girth weld - Google Patents

Abstract

The application discloses a laser-CMT efficient welding method and device for a sheet girth weld, comprising the following steps of S1, removing impurities on the surface of a workpiece and clamping the workpiece; s2, sequentially arranging welding wires, a TIG welding gun, a first laser beam, a second laser beam and a CMT welding gun on a welding side along a welding direction, wherein the TIG welding gun is positioned right above a workpiece, and the first laser beam is used for forming a keyhole type molten pool on the surface of the workpiece; s3, arranging jet protection components on two sides of the circumferential weld of the workpiece, wherein the jet protection components are used for jetting protection gas to the welding position; s4, arranging swinging devices on the welding wire, the TIG welding gun, the first laser beam, the second laser beam, the CMT welding gun and the jet protection assembly. The application can reduce the welding deformation of the sheet annular piece and realize the high-efficiency welding of large filling quantity. The welding seam forming quality is improved, the generation of welding defects is reduced, and the welding seam structure and mechanical properties are improved.

Description

laser-CMT efficient welding method and device for sheet girth weld

Technical Field

The application belongs to the technical field of sheet welding, and particularly relates to a sheet girth weld laser-CMT efficient welding method and device.

Background

In the industrial fields of petroleum pipelines, pressure vessel storage tanks and the like, circumferential welds are commonly used, and common welding methods include: the manual welding and the consumable electrode gas shielded automatic welding have low welding efficiency, and the post-welding heat treatment, post-welding correction deformation and other complex procedures are also needed.

At present, a laser-GMA composite welding process is mainly applied in the field of girth welding, but welding current is required to be increased in order to increase the melting amount of welding wires, so that the heat input of the GMA current to a base metal is overlarge, the size of a molten pool is overlarge, and welding defects such as liquid metal dripping, weld puddles and the like appear. For sheet welding, large deformations are also easily caused by large heat inputs.

The cold metal transition technology (Cold Metal Transfer, abbreviated as CMT) is a novel digital welding method developed by the front company on the basis of MIG/MAG welding based on the principle of short circuit transition. Unlike the traditional MIG/MAG welding mode, which increases electromagnetic force to promote molten drop transition, the technology adopts the method of drawing back welding wire to assist molten drop transition, realizes molten drop short circuit transition in zero current state, can effectively reduce welding heat input, and is a stable and splash-free welding process.

In the technical scheme, two TIG electric arcs and laser beams are required to be combined to act on a molten pool together, so that heat input to a base metal is overlarge. For sheet welding, large deformations are also easily caused by large heat inputs. And the filling position of the welding wire is positioned at 12 o 'clock and 3 o' clock, and the molten drops are melted into a molten pool to easily generate a dripping phenomenon, so that the defects of weld flash are generated, and the stability of the welding process is affected.

Disclosure of Invention

In order to solve the technical problems, the application provides a laser-CMT efficient welding method and device for sheet girth weld, which can reduce welding deformation of sheet annular parts and realize efficient welding with large filling quantity. The welding seam forming quality is improved, the generation of welding defects is reduced, and the welding seam structure and mechanical properties are improved.

In order to achieve the aim, the application provides a laser-CMT efficient welding method for sheet girth weld, which comprises the following steps of,

s1, removing impurities on the surface of a workpiece and clamping the workpiece;

s2, sequentially arranging a welding wire, a TIG welding gun, a first laser beam, a second laser beam and a CMT welding gun on a welding side along a welding direction, wherein the TIG welding gun is positioned right above the workpiece, and the first laser beam is used for forming a keyhole type molten pool on the surface of the workpiece;

s3, arranging jet protection components on two sides of the circumferential weld of the workpiece, wherein the jet protection components are used for jetting protection gas to a welding position;

s4, arranging a swinging device on the welding wire, the TIG welding gun, the first laser beam, the second laser beam, the CMT welding gun and the jet protection component, wherein the swinging device is used for driving the welding wire, the TIG welding gun, the first laser beam, the second laser beam, the CMT welding gun and the jet protection component to swing synchronously;

s5, starting a TIG power supply, a CMT power supply, a swinging device, a wire feeding mechanism and an air injection protection assembly, and rotating the workpiece to weld.

Further, in step S3, the jet protection assembly includes a first protection gas nozzle and a second protection gas nozzle, the first protection gas nozzle is located at the outer side of the workpiece and corresponds to the outer wall of the girth weld, a first protection gas is circulated in the first protection gas nozzle, the second protection gas nozzle is located at the inner side of the workpiece and corresponds to the inner wall of the girth weld, a second protection gas is circulated in the second protection gas nozzle, the first protection gas and the second protection gas are argon or helium, the flow of the first protection gas in the first protection gas nozzle is 1L-100L/min, and the flow of the second protection gas in the second protection gas nozzle is 1L-60L/min.

Further, in step S5, the negative electrode of the TIG power supply is connected to the TIG welding gun, the positive electrode of the TIG power supply is connected to the welding wire, the positive electrode of the CMT power supply is connected to the CMT welding gun, the negative electrode of the CMT power supply is connected to the workpiece, the current of the TIG power supply is 60A to 300A, and the CMT welding current is 10A to 300A.

In step S1, the gap width between two adjacent workpieces is 0.01mm 1-mm, and the thickness of the workpieces is not more than 5mm.

Further, in step S2, the distance between the TIG welding torch heat source and the welding wire is-1 mm-2 mm, the distance between the TIG welding torch heat source and the heat source of the first laser beam is 0 mm-2 mm, the distance between the first laser beam and the second laser beam is 0.6 mm-2 mm, and the distance between the welding wire of the CMT welding torch and the light wire of the second laser beam is 0 mm-1 mm.

Further, in step S5, the wire feeding mechanism is a wire feeding tube, the welding wire is located in the wire feeding tube, and the wire feeding speed of the welding wire is 0.1 m-10 m/min.

Further, in step S2, the power of the first laser beam is 800W to 10000W, and the power of the second laser beam is 80W to 3000W.

The utility model provides a high-efficient welding set of sheet metal girth weld laser-CMT, includes TIG welding system, laser subassembly, the CMT welding system that sets gradually along the welding direction, wherein,

the TIG welding system comprises a welding wire, a TIG welding gun and a TIG power supply, wherein the TIG power supply is electrically connected with the welding wire and the TIG welding gun, the laser assembly comprises a first laser head close to the TIG welding gun and a second laser head which is positioned on the first laser head and far away from the TIG welding gun, the CMT welding system comprises a CMT welding gun and a CMT power supply, and the CMT power supply is electrically connected with the CMT welding gun and the workpiece;

the TIG welding system, the laser beam assembly and the CMT welding system are fixedly connected with the swinging device;

the air injection protection assembly is provided with two air injection ends, and the two air injection ends respectively correspond to the outer wall and the inner wall of the girth weld.

Further, the first laser head and the second laser head are Nd: YAG laser and CO ₂ One of a laser and a fiber laser.

Compared with the prior art, the application has the following advantages and technical effects:

1. according to the technical scheme, the TIG welding gun and the welding wire are positioned right above the workpiece, so that liquid molten drops are favorable for continuously flowing into a molten pool after the welding wire is melted, and the welding seam forming quality is favorable for being improved.

And 2, the TIG welding gun, the welding wire and the TIG power supply are matched for use, so that high-efficiency welding with large filling quantity can be realized, the influence on heat input of a base metal is small, and welding deformation is small. Greatly reduces the deformation of the joint, and leads the crystal grains of the weld joint structure of the base material to be tiny and the mechanical property to be improved.

3. Through setting up jet protection subassembly, spray the shielding gas to girth weld both sides to can prevent that liquid metal from flowing down and welding defects such as welding seam couch, further improve welding seam shaping quality.

4. The second laser beam and the CMT welding gun are matched for use, in the laser-CMT composite welding process, the second laser beam and the electric arc form a composite heat source, the guiding effect of the laser on the electric arc enables the welding process to be more stable, the energy utilization rate is greatly improved, the welding wire of the CMT welding gun is far away from the first laser beam, the impact of welding wire melting transition to a keyhole formed by the first laser beam in a molten pool is small, and the stability of the welding process is improved. The method avoids the large heat input to the base metal caused by the increase of the welding current for increasing the cladding amount of the filling metal in the conventional laser-MIG/MAG composite welding, and further avoids the occurrence of liquid metal dripping and weld flash caused by overlarge molten pool volume.

5. The swinging device drives the parts to move simultaneously, so that the sidewall fusion property of the weld joint gap of the annular part is improved, and the welding defect is avoided.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

FIG. 1 is a schematic structural view of a laser-CMT high-efficiency welding device for sheet girth welds;

FIG. 2 is a schematic diagram of a weld cross section of a conventional laser-CMT hybrid welding method for circumferential seams;

FIG. 3 is a schematic view of a longitudinal section of a weld joint of a conventional laser-CMT composite welding method for circumferential seams;

FIG. 4 is a schematic view of a weld cross section of the method of the present technique;

FIG. 5 is a schematic view of a longitudinal section of a weld seam of the method of the present solution;

the welding device comprises a 1-TIG power supply, a 2-wire feeding tube, a 3-welding wire, a 4-TIG welding gun, a 5-first laser beam, a 6-second laser beam, a 7-CMT welding gun, an 8-CMT power supply, a 9-first protective gas nozzle, a 10-first protective gas, a 11-workpiece, a 12-second protective gas, a 13-second protective gas nozzle and a 14-swinging device.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

In order that the above-recited objects, features and advantages of the present application will become more readily apparent, a more particular description of the application will be rendered by reference to the appended drawings and appended detailed description.

Referring to fig. 1-5, the present application provides a laser-CMT efficient welding method for girth weld of thin plates, comprising,

s1, removing impurities on the surface of the workpiece 11 and clamping the workpiece 11. The workpiece 11 is a thin plate annular base material, the surface of the base material is treated to remove impurities on the surface of the workpiece 11, and after the workpiece 11 is treated, the workpiece 11 is clamped on a workbench (not shown in the figure), and the workbench can rotate the workpiece 11.

S2, a welding wire 3, a TIG welding gun 4, a first laser beam 5, a second laser beam 6 and a CMT welding gun 7 are sequentially arranged on the welding side along the welding direction, the TIG welding gun 4 is located right above a workpiece 11, and the first laser beam 5 is used for forming a keyhole type molten pool on the surface of the workpiece 11.

The TIG welding gun 4 is positioned to be positioned right above the workpiece 11, namely, the circumferential weld 12 o' clock direction, and the welding wire 3, the TIG welding gun 4, the first laser beam 5, the second laser beam 6 and the CMT welding gun 7 are sequentially arranged above the workpiece 11 according to the rotation direction and the welding direction of the workpiece 11, wherein the first laser beam 5 is a high-energy laser beam, the function of the first laser beam 5 is to form a keyhole type molten pool on the surface of the workpiece 11, and the second laser beam 6 is a low-energy laser beam, and the keyhole type molten pool is not formed on the surface of the workpiece 11.

S3, arranging jet protection components on two sides of the girth weld of the workpiece 11, wherein the jet protection components are used for spraying protection gas to the welding position. Above and below the work piece 11 are respectively provided structures for injecting a shielding gas for providing shielding gas for the welding process.

S4, arranging a swinging device 14 on the welding wire 3, the TIG welding gun 4, the first laser beam 5, the second laser beam 6, the CMT welding gun 7 and the jet protection component, wherein the swinging device 14 is used for driving the welding wire 3, the TIG welding gun 4, the first laser beam 5, the second laser beam 6, the CMT welding gun 7 and the jet protection component to swing synchronously.

The swinging device 14 is used for connecting the welding wire 3, the TIG welding gun 4, the first laser beam 5, the second laser beam 6, the CMT welding gun 7 and the jet protection component, and under the action of the swinging device, the components can swing along with the swinging device at the same time, so that the normal operation of welding is ensured.

Specifically, first, the welding wire 3, TIG torch 4, first laser beam 5, second laser beam 6, CMT torch 7, and jet protection component are connected by a jig, and then the jig is connected to the swinging device 14.

S5, starting the TIG power supply 1, the CMT power supply 8, the swinging device 14, the wire feeding mechanism and the air injection protection assembly, and welding the rotary workpiece 11.

Fig. 2 and 3 are schematic views of a cross section and a longitudinal section of a weld joint in a conventional circumferential seam laser-CMT composite welding method (i.e., only the first laser beam 5 and the CMT welding gun 7 in fig. 1), and fig. 2 is a cross section of a weld joint, in which an incomplete welding defect appears at the bottom of the weld joint, and an incomplete welding defect appears at the right side of the surface of the weld joint; fig. 3 shows a longitudinal section of a weld joint, where the longitudinal section of the weld joint has air hole defects, and the upper surface and the lower surface of the longitudinal section of the weld joint are seen to be fluctuant, because the CMT welding gun 7 needs to melt the base metal after the first laser beam 5 is in front of the first laser beam along the welding direction, and the gap reserved between the workpieces 11 is reserved, so that the laser beam is easy to leak out of the gap, the energy utilization rate of the laser on the workpieces 11 is reduced, the welding stability is poor, the weld joint is formed worse, and the welding defect that the weld joint is not fused easily occurs. Because the CMT welding gun 7 is closer to the first laser beam 5 forming the keyhole type molten pool, the welding wire is easy to impact the keyhole after melting, and welding bubbles are generated after the keyhole collapses, thereby causing welding pore defects.

Fig. 4 and 5 are schematic diagrams of a weld cross section and a longitudinal section of the method according to the technical scheme, fig. 4 is a weld cross section, fig. 5 is a weld longitudinal section, it is seen that the weld is well formed, no welding defect occurs, and the surface and the back of the weld are continuously formed. This is because: the TIG welding gun 4 and the welding wire 3 are positioned at 12 o' clock, which is beneficial to the continuous flow of liquid droplets into a molten pool after the welding wire 3 is melted and the improvement of the welding seam forming quality. The TIG welding gun 4 and the welding wire 3 are respectively connected with one pole of the TIG power supply 1, so that high-efficiency welding with large filling quantity can be realized, the influence on the heat input of the workpiece 11 is small, and the welding deformation is small. Greatly reduces the deformation of the joint, and leads the weld joint structure of the workpiece 11 to have fine grains and improved mechanical properties. The molten pools above and at the back of the girth weld are provided with protective gas nozzles for spraying protective gas, so that welding defects such as liquid metal flowing down and welding seam laying are prevented, and further welding seam forming quality is improved. In the laser-CMT composite welding process, the laser and the electric arc form a composite heat source, and the guiding effect of the laser on the electric arc ensures that the welding process is more stable, and the energy utilization rate is greatly improved.

The second laser beam 6 and the electric arc form a composite heat source, and the guiding effect of the laser on the electric arc enables the welding process to be more stable, so that the energy utilization rate is greatly improved; and the welding wire of the CMT welding gun 7 is far away from the first laser beam 5, so that the impact of the welding wire melting transition to the molten pool on a key hole formed by the first laser beam 5 is small, and the stability of the welding process is improved.

In a further optimized scheme, in step S3, the jet protection assembly includes a first protection gas nozzle 9 and a second protection gas nozzle 13, the first protection gas nozzle 9 is located at the outer side of the workpiece 11 and corresponds to the outer wall of the girth weld, a first protection gas 10 circulates in the first protection gas nozzle 9, the second protection gas nozzle 13 is located at the inner side of the workpiece 11 and corresponds to the inner wall of the girth weld, a second protection gas 12 circulates in the second protection gas nozzle 13, the first protection gas 10 and the second protection gas 12 are argon or helium, the flow of the first protection gas 10 in the first protection gas nozzle 9 is 1L to 100L/min, and the flow of the second protection gas 12 in the second protection gas nozzle 13 is 1L to 60L/min.

It will be appreciated that the flow rate of the first shielding gas 10 is relatively high, so that it can "lift" the molten bath metal and prevent the liquid metal from dripping: the second shielding gas 12 is primarily intended to prevent the molten bath metal from forming "bump" defects inside the annular workpiece under the force of gravity.

It will be appreciated that the first shielding gas nozzle 9 is located on the outer wall of the workpiece 11, i.e. above the girth weld, and the second shielding gas nozzle 13 is located on the inner wall of the workpiece 11, i.e. on the back of the girth weld, while the first shielding gas nozzle 9 and the second shielding gas nozzle 13 are symmetrically arranged on both sides of the girth weld pool.

In a further optimization scheme, in the step S5, the negative electrode of the TIG power supply 1 is connected with the TIG welding gun 4, the positive electrode of the TIG power supply 1 is connected with the welding wire 3, the positive electrode of the CMT power supply 8 is connected with the CMT welding gun 7, the negative electrode of the CMT power supply 8 is connected with the workpiece 11, the current of the TIG power supply 1 is 60A-300A, and the welding current of the CMT is 10A-300A.

With this arrangement, the TIG welding gun 4 and the welding wire 3 are connected to one electrode of the TIG power source 1, so that efficient welding with a large filling amount can be realized, the influence on the heat input of the base material is small, and the welding deformation is small. Greatly reduces the deformation of the joint, and leads the crystal grains of the weld joint structure of the base material to be tiny and the mechanical property to be improved.

In a further optimization scheme, in the step S1, the gap width between two adjacent workpieces 11 is 0.01-1 mm, and the thickness of the workpieces 11 is not more than 5mm.

In a further optimized scheme, in the step S2, the distance between the heat source of the TIG welding gun 4 and the welding wire 3 is-1 mm-2 mm, the distance between the heat source of the TIG welding gun 4 and the heat source of the first laser beam 5 is 0 mm-2 mm, the distance between the first laser beam 5 and the second laser beam 6 is 0.6 mm-2 mm, and the distance between the welding wire of the CMT welding gun 7 and the light wire of the second laser beam 6 is 0 mm-1 mm.

In a further optimized scheme, in the step S5, the wire feeding mechanism is a wire feeding pipe 2, the welding wire 3 is positioned in the wire feeding pipe 2, and the wire feeding speed of the welding wire 3 is 0.1-10 m/min.

The welding wire feeding pipe 2 is used for carrying out wire feeding operation on the welding wire 3, so that normal welding is ensured.

In a further optimization scheme, in the step S2, the power of the first laser beam 5 is 800W-10000W, and the power of the second laser beam 6 is 80W-3000W.

The utility model provides a high-efficient welding set of sheet metal girth weld laser-CMT, includes TIG welding system, laser subassembly, the CMT welding system that sets gradually along the welding direction, wherein,

the TIG welding system comprises a welding wire 3, a TIG welding gun 4 and a TIG power supply 1, wherein the TIG power supply 1 is electrically connected with the welding wire 3 and the TIG welding gun 4, the laser assembly comprises a first laser head close to the TIG welding gun 4 and a second laser head which is positioned on the first laser head and far away from the TIG welding gun 4, the CMT welding system comprises a CMT welding gun 7 and a CMT power supply 8, and the CMT power supply 8 is electrically connected with the CMT welding gun 7 and a workpiece 11;

the swinging device 14, the TIG welding system, the laser beam component and the CMT welding system are fixedly connected with the swinging device 14;

the air injection protection assembly is provided with two air injection ends, and the two air injection ends respectively correspond to the outer wall and the inner wall of the girth weld.

Further optimizing scheme, first laser head and second laser head are Nd: YAG laser and CO ₂ One of a laser and a fiber laser.

The present application is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present application are intended to be included in the scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims (9)

1. A laser-CMT efficient welding method for sheet girth weld is characterized in that: comprising the steps of (a) a step of,

s1, removing impurities on the surface of a workpiece (11) and clamping the workpiece (11);

s2, sequentially arranging a welding wire (3), a TIG welding gun (4), a first laser beam (5), a second laser beam (6) and a CMT welding gun (7) on a welding side along a welding direction, wherein the TIG welding gun (4) is positioned right above the workpiece (11), and the first laser beam (5) is used for forming a keyhole type molten pool on the surface of the workpiece (11);

s3, arranging jet protection components on two sides of the girth weld of the workpiece (11), wherein the jet protection components are used for jetting protection gas to a welding position;

s4, arranging a swinging device (14) on a welding wire (3), a TIG welding gun (4), a first laser beam (5), a second laser beam (6), a CMT welding gun (7) and an air jet protection assembly, wherein the swinging device (14) is used for driving the welding wire (3), the TIG welding gun (4), the first laser beam (5), the second laser beam (6), the CMT welding gun (7) and the air jet protection assembly to swing synchronously;

s5, starting a TIG power supply (1), a CMT power supply (8), a swinging device (14), a wire feeding mechanism and an air injection protection assembly, and welding a rotary workpiece (11).

2. The method for laser-CMT efficient welding of sheet girth welds of claim 1, wherein: in step S3, the jet protection assembly includes a first protection gas nozzle (9) and a second protection gas nozzle (13), the first protection gas nozzle (9) is located outside the workpiece (11) and corresponds to the outer wall of the girth weld, a first protection gas (10) is flowed through in the first protection gas nozzle (9), the second protection gas nozzle (13) is located inside the workpiece (11) and corresponds to the inner wall of the girth weld, a second protection gas (12) is flowed through in the second protection gas nozzle (13), the first protection gas (10) and the second protection gas (12) are argon or helium, the flow of the first protection gas (10) in the first protection gas nozzle (9) is 1L-100L/min, and the flow of the second protection gas (12) in the second protection gas nozzle (13) is 1L-60L/min.

3. The method for laser-CMT efficient welding of sheet girth welds of claim 1, wherein: in the step S5, the negative electrode of the TIG power supply (1) is connected with the TIG welding gun (4), the positive electrode of the TIG power supply (1) is connected with the welding wire (3), the positive electrode of the CMT power supply (8) is connected with the CMT welding gun (7), the negative electrode of the CMT power supply (8) is connected with the workpiece (11), the current of the TIG power supply (1) is 60A-300A, and the CMT welding current is 10A-300A.

4. The method for laser-CMT efficient welding of sheet girth welds of claim 1, wherein: in the step S1, the width of a gap between two adjacent workpieces (11) is 0.01-1 mm, and the thickness of the workpieces (11) is not more than 5mm.

5. The method for laser-CMT efficient welding of sheet girth welds of claim 1, wherein: in the step S2, the distance between the heat source of the TIG welding gun (4) and the welding wire (3) is-1 mm-2 mm, the distance between the heat source of the TIG welding gun (4) and the heat source of the first laser beam (5) is 0 mm-2 mm, the distance between the first laser beam (5) and the second laser beam (6) is 0.6 mm-2 mm, and the distance between the welding wire of the CMT welding gun (7) and the optical wire of the second laser beam (6) is 0 mm-1 mm.

6. The method for laser-CMT efficient welding of sheet girth welds of claim 1, wherein: in the step S5, the wire feeding mechanism is a wire feeding tube (2), the welding wire (3) is positioned in the wire feeding tube (2), and the wire feeding speed of the welding wire (3) is 0.1-10 m/min.

7. The method for laser-CMT efficient welding of sheet girth welds of claim 1, wherein: in the step S2, the power of the first laser beam (5) is 800-10000W, and the power of the second laser beam (6) is 80-3000W.

8. A laser-CMT efficient welding device for sheet girth welds, which is used for the laser-CMT efficient welding method for sheet girth welds according to any one of claims 1 to 7, and is characterized in that: comprises a TIG welding system, a laser component and a CMT welding system which are sequentially arranged along the welding direction, wherein,

the TIG welding system comprises a welding wire (3), a TIG welding gun (4) and a TIG power supply (1), wherein the TIG power supply (1) is electrically connected with the welding wire (3) and the TIG welding gun (4), the laser assembly comprises a first laser head close to the TIG welding gun (4) and a second laser head located at the first laser head and far away from the TIG welding gun (4), the CMT welding system comprises a CMT welding gun (7) and a CMT power supply (8), and the CMT power supply (8) is electrically connected with the CMT welding gun (7) and the workpiece (11);

the swing device (14), the TIG welding system, the laser beam assembly and the CMT welding system are fixedly connected with the swing device (14);

the air injection protection assembly is provided with two air injection ends, and the two air injection ends respectively correspond to the outer wall and the inner wall of the girth weld.

9. The sheet girth weld laser-CMT high performance welding apparatus of claim 8, wherein: the first laser head and the second laser head are Nd: YAG laser and CO ₂ One of a laser and a fiber laser.