CN114523207A - Laser welding device, laser welding equipment and laser welding method - Google Patents

Laser welding device, laser welding equipment and laser welding method Download PDF

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Publication number
CN114523207A
CN114523207A CN202210204483.1A CN202210204483A CN114523207A CN 114523207 A CN114523207 A CN 114523207A CN 202210204483 A CN202210204483 A CN 202210204483A CN 114523207 A CN114523207 A CN 114523207A
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welding
light
reflector
laser
workpiece
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CN114523207B (en
Inventor
王立伟
顾云飞
梁志敏
汪殿龙
刘�英
彭珍珍
姚云峰
梁永梅
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Hebei University of Science and Technology
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Hebei University of Science and Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/21—Bonding by welding
    • B23K26/24—Seam welding
    • B23K26/26—Seam welding of rectilinear seams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/04—Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
    • B23K26/046—Automatically focusing the laser beam
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • B23K26/0643—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising mirrors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/067—Dividing the beam into multiple beams, e.g. multifocusing
    • B23K26/0676—Dividing the beam into multiple beams, e.g. multifocusing into dependently operating sub-beams, e.g. an array of spots with fixed spatial relationship or for performing simultaneously identical operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/18—Dissimilar materials
    • B23K2103/20—Ferrous alloys and aluminium or alloys thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Laser Beam Processing (AREA)

Abstract

The invention provides a laser welding device and laser welding equipment, comprising a laser generator, a first reflector, a second reflector and a focusing mechanism; the first reflector and the second reflector are sequentially arranged on the light emitting side of the laser generator along the propagation path of the initial light beam; the first reflector is provided with a light transmitting area which is coaxial with the initial light beam, and the diameter of the light transmitting area is smaller than that of the initial light beam; part of light rays of the initial light beam are reflected to the surface of the workpiece by the first reflector to form annular preheating light spots; the light rays of the other initial light beams penetrate through the light-transmitting area, and the second reflector reflects the light rays penetrating through the light-transmitting area to the surface of the workpiece to form solid welding light spots; the preheating spot is located in front of the welding spot. The butt joint method is suitable for butt joint between dissimilar metals, not only ensures the welding quality, but also reduces the manufacturing difficulty and the welding difficulty of components. The invention also provides a laser welding method, which has the advantages of convenient parameter selection, simple welding process, better preheating effect and higher welding quality.

Description

Laser welding device, laser welding equipment and laser welding method
Technical Field
The invention belongs to the technical field of dissimilar metal welding, and particularly relates to a laser welding device, laser welding equipment and a laser welding method.
Background
With the increasingly deep influence of concepts of energy conservation, emission reduction and environmental protection on production and life, the automobile industry attaches more importance to the problems of energy consumption and exhaust emission. If the weight of the automobile is reduced by 10%, the fuel oil use efficiency can be improved by 6% -8%, and the weight of the automobile becomes one of important parameters influencing the energy consumption of the automobile.
In order to meet the design requirement of light weight of the automobile, the light-weight, high-strength and corrosion-resistant aluminum alloy becomes an important part substitute material, and the weight of the automobile body can be effectively reduced. However, steel and aluminum alloy cannot be unilaterally replaced by each other due to their unique service performance and mechanical properties, so that welding of dissimilar metals of steel and aluminum is widely applied in the automobile manufacturing process. The steel and the aluminum have larger difference of thermal and physical performance parameters such as melting points, and intermetallic compounds are generated during welding to increase the brittleness of a welding joint, so that a large amount of microcracks are easy to appear, and stress concentration is generated. The laser welding dissimilar metal has the characteristics of concentrated energy density, small heat affected zone, small welding deformation and large depth-to-width ratio of a welding seam, and has the advantages of good appearance, continuous welding seam and less welding defects in the aspect of welding seam forming. At present, for laser welding of steel and aluminum dissimilar metals, the influence caused by difference of thermal physical properties between two materials still needs to be weakened by using an overlapping mode, the thickness of a welding position is large due to the overlapping joint, the welding operation difficulty is high, and the manufacturing difficulty of a workpiece to be welded is improved.
Disclosure of Invention
The embodiment of the invention provides a laser welding device, laser welding equipment and a laser welding method, aiming at reducing the operation difficulty of dissimilar metal welding and improving the applicability of a laser welding technology.
In order to achieve the purpose, the invention adopts the technical scheme that:
in a first aspect, there is provided a laser welding apparatus comprising:
the focusing device comprises a laser generator, a first reflector, a second reflector and a focusing mechanism;
the laser generator is used for generating an initial light beam;
the first reflector and the second reflector are sequentially arranged on the light-emitting side of the laser generator along the propagation path of the initial light beam;
the first reflector is provided with a light-transmitting area which is coaxial with the initial light beam, and the diameter of the light-transmitting area is smaller than that of the initial light beam;
part of the light rays of the initial light beam are reflected to the surface of the workpiece by the first reflector so as to form an annular preheating light spot on the surface of the workpiece; the light rays of the rest initial light beams penetrate through the light-transmitting area, and the second reflector reflects the light rays penetrating through the light-transmitting area to the surface of the workpiece so as to form a solid welding light spot on the surface of the workpiece; in the welding direction, the preheating light spot is positioned in front of the welding light spot;
the focusing mechanism is used for focusing the light reflected by the first reflector and the light reflected by the second reflector respectively.
With reference to the first aspect, in a possible implementation manner, the focusing mechanism includes a first focusing unit and a second focusing unit, where the first focusing unit is disposed corresponding to the first reflecting mirror, and the second focusing unit is disposed corresponding to the second reflecting mirror.
Compared with the prior art, the scheme shown in the embodiment of the application has the advantages that a laser generator generates a light source, the light source is ingeniously split by using the first reflector, one part of the light is directly reflected by the first reflector and can form a hollow annular preheating light spot on the surface of a workpiece, the other part of the light is reflected by the second reflector to form a solid welding light spot, the preheating by using the preheating light spot is firstly realized at the butt-joint seam position of the surface of the workpiece (so that dissimilar metals reach proper welding temperature), then the welding process by using the welding light spot is utilized, the mechanical property of a welding joint can be effectively improved, a butt-joint mode can be adopted among the dissimilar metals, the thickness of the welding position is reduced, and the joint form of laser welding is widened; meanwhile, the preheating light spot is annular, so that the penetrating power of the preheating light spot is low, the preheating light spot has a larger diameter, and uniform preheating can be realized on the surface of the workpiece. The laser welding device of the embodiment of the application is suitable for a butt joint mode between dissimilar metals, not only ensures the welding quality, but also reduces the manufacturing difficulty and the welding difficulty of components.
In a second aspect, an embodiment of the present invention further provides a laser welding apparatus, including:
the workbench is used for fixing a workpiece to be welded; and
the laser welding device is arranged on the workbench.
With reference to the second aspect, in a possible implementation manner, the laser welding apparatus further includes:
the protective gas mechanism is arranged on the workbench and used for conveying protective gas to a specified position; and
and the powder feeding mechanism is arranged on the workbench and used for feeding solder to a specified position.
Compared with the prior art, the scheme shown in the embodiment of the application can perform better laser welding operation between dissimilar metals fixed on the workbench by adopting the laser welding device, and can effectively weaken the influence caused by the difference of thermal and physical properties between the dissimilar metals.
In a third aspect, an embodiment of the present invention further provides a laser welding method, which is implemented based on the above laser welding apparatus, and includes the following steps:
acquiring a laser power parameter and a welding speed parameter according to preset parameters of a workpiece;
acquiring the spot distance between a preheating spot and a welding spot, and adjusting the included angle between a reflected beam of the first reflecting mirror and a reflected beam of the second reflecting mirror, the defocusing amount of the preheated laser beam and the defocusing amount of the welded laser beam according to the spot distance;
and welding along a preset path according to the welding speed parameter, wherein the preset path is a butt joint seam of the workpiece.
With reference to the third aspect, in a possible implementation manner, the acquiring the spot pitch of the preheating spot and the welding spot specifically includes:
and acquiring the light spot space according to the thickness of the workpiece.
With reference to the third aspect, in a possible implementation manner, the adjusting the reflection angle of the first mirror and the second mirror according to the inter-spot distance specifically includes:
according to a formula
Figure BDA0003528606490000031
Acquiring an included angle between a light beam reflected by the first reflecting mirror and a light beam reflected by the second reflecting mirror;
wherein θ is an included angle between the light beam reflected by the first reflector and the light beam reflected by the second reflector;
L0is the spot spacing;
L1the distance between the center point of the reflection area of the first reflector and the center point of the reflection area of the second reflector is set;
L2the vertical distance from the central point of the reflecting area of the first reflecting mirror to the surface of the workpiece.
With reference to the third aspect, in a possible implementation manner, the obtaining of the welding speed parameter according to the preset parameter of the workpiece specifically includes:
and acquiring welding speed parameters according to the thickness of the workpiece.
With reference to the third aspect, in a possible implementation manner, before welding along a preset path according to the welding speed parameter, the method further includes:
and introducing protective gas from the side surface of the workpiece.
With reference to the third aspect, in a possible implementation manner, before welding along a preset path according to the welding speed parameter, the method further includes:
heating the workpiece to a preset temperature, and keeping the workpiece at the preset temperature for a preset time;
the preset temperature is not lower than the vaporization temperature of the water.
Compared with the prior art, the scheme shown in the embodiment of the application has the advantages that the parameters are convenient to select, the welding process is simple, the preheating effect is better, the welding quality is higher, the scheme is suitable for the welding operation of butt joint between dissimilar metals, and the applicability of a laser welding process is improved.
Drawings
Fig. 1 is a schematic view illustrating a usage state of a laser welding apparatus according to an embodiment of the present invention;
FIG. 2 is an enlarged view of a portion of the surface of the workpiece of FIG. 1;
fig. 3 is a schematic structural diagram of a laser welding apparatus according to an embodiment of the present invention;
fig. 4 is a schematic view of an assembly structure of the rotary switching mechanism and the first reflector according to the second embodiment of the present invention.
Description of reference numerals:
1. a laser generator;
2. a first reflector;
3. a second reflector;
4. a focusing mechanism; 410. a first focusing unit; 420. a second focusing unit;
5. an initial beam of light;
6. a light-transmitting region;
7. a workpiece; 710. a plate body;
8. preheating the light spots;
9. welding light spots;
10. butt jointing and edge joint;
11. welding seams;
12. presetting an axis;
13. a connecting frame;
14. a deflector rod;
15. shifting blocks;
16. sensing a patch;
17. an annular track.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the present embodiment, the workpiece 7 is exemplarily shown as being formed by two plate bodies 710 butted together, one of the two plate bodies is an aluminum plate, the other is a steel plate, and the hollow arrows on the workpiece 7 show the welding direction.
Referring to fig. 1 to 3, a laser welding apparatus according to the present invention will now be described. The laser welding device comprises a laser generator 1, a first reflector 2, a second reflector 3 and a focusing mechanism 4; the laser generator 1 is used for generating an initial light beam 5; the first reflector 2 and the second reflector 3 are sequentially arranged on the light emitting side of the laser generator 1 along the propagation path of the initial light beam 5; the first reflector 2 is provided with a light-transmitting area 6 which is coaxial with the initial light beam 5, and the diameter of the light-transmitting area 6 is smaller than that of the initial light beam 5; the focusing mechanism 4 is used for focusing the light reflected by the first reflecting mirror 2 and the light reflected by the second reflecting mirror 3, respectively.
Part of the light of the initial light beam 5 is reflected to the surface of the workpiece 7 by the first reflector 2 to form an annular preheating light spot 8 on the surface of the workpiece 7; the light rays of the rest initial light beams 5 penetrate through the light-transmitting area 6, and the second reflecting mirror 3 reflects the light rays penetrating through the light-transmitting area 6 to the surface of the workpiece 7 so as to form a solid welding spot 9 on the surface of the workpiece 7; in the welding direction, the preheating spot 8 is located before the welding spot 9.
The laser welding apparatus of the present embodiment has two welding guns, one of which is used to project the light beam reflected by the first reflecting mirror 2 and the other of which is used to project the light beam reflected by the second reflecting mirror 3.
Compared with the prior art, the laser welding device provided by the embodiment has the following advantages:
1. the laser generator 1 generates a light source, the first reflector 2 is utilized to ingeniously split the light (initial light beam 5), one part of the light is directly reflected and can form a hollow annular preheating light spot 8 on the surface of the workpiece 7, the other part of the light is reflected by the second reflector 3 to form a solid welding light spot 9, the preheating by the preheating light spot 8 is firstly realized at the butt joint seam 10 position on the surface of the workpiece 7 (so that dissimilar metals reach proper welding temperature), and then the welding process by the welding light spot 9 is utilized, so that the problem that two metals cannot be simultaneously molten during welding due to melting point difference is solved, the mechanical property of a welding joint can be effectively improved, a butt joint mode can be adopted between the dissimilar metals, the thickness of a welding position is reduced, and the joint form of laser welding is widened; meanwhile, the preheating light spot 8 is annular, so that the penetrating power of the preheating light spot is low, the preheating light spot has a larger diameter, and uniform preheating can be realized on the surface of the workpiece 7. The laser welding device of the embodiment of the application is suitable for a butt joint mode between dissimilar metals, not only ensures the welding quality, but also reduces the manufacturing difficulty and the welding difficulty of components.
2. According to the embodiment of the application, the preheating and the welding can be simultaneously completed by adopting one laser source, so that the setting difficulty of the laser source is reduced to a great extent, and the integral structure of the device is simplified; meanwhile, the adjustment of the defocusing amount is completed through the focusing mechanism 4, so that the preheating and welding temperature can be respectively adjusted according to the actual condition under the condition of not changing the power of the light source, and the use is more flexible.
3. In the embodiment of the application, the hollow light beam generates the circular light spot, and due to the unique hollow structure, when the laser welding is used for welding metal with high heat sensitivity, extra heat input during preheating of the welding seam can be avoided, so that the controllability of the heat input to preheating areas on two sides of the welding seam is enhanced, and the limitation of the heat sensitivity of the plate is avoided.
In specific implementation, in order to fully utilize laser energy, the mirror surface of the first reflector 2 forms an angle of 45 degrees with the tangent line of the corresponding preheating point, so that reflected light can be projected to the preheating point along the normal direction of the preheating point. Taking the example that the two plates 710 of the workpiece 7 are both flat plates, the mirror surface of the first reflector 2 forms an angle of 45 ° with the plate surface of the plate 710.
In addition, the middle part of the second reflector 3 is connected with an angle adjusting mechanism which can adjust the included angle between the mirror surface of the second reflector 3 and the tangent of the welding point, and then adjust the projection angle of the welding beam. Taking the example that the two plates 710 of the workpiece 7 are both flat plates, the included angle of the mirror surface of the second reflecting mirror 3 relative to the plate surface 710 can be adjusted, and meanwhile, the central position of the second reflecting mirror 3 can be ensured to be aligned with the center of the initial light beam 5 all the time. The first reflecting mirror 2 is also provided with a similar angle adjusting mechanism for angle adjustment according to the shape of the workpiece 7.
In some embodiments, the ratio of the diameter of the light-transmissive region 6 to the diameter of the initial beam 5 is 1:4 to 3:4. to make the preheating energy and the welding energy more balanced, the ratio of the diameter of the light-transmissive region 6 to the diameter of the initial beam 5 is preferably 1: 2.
In specific implementation, the light-transmitting region 6 may be formed by directly forming a hole on the first reflector 2, as shown in fig. 1; the light-transmitting region 6 may be formed by glass or another transparent member having good light-transmitting properties, which is not shown in the figure. The other embodiments are not listed, and the requirement of light transmission performance can be met.
In some embodiments, referring to fig. 1 and 3, the focusing mechanism 4 includes a first focusing unit 410 and a second focusing unit 420, the first focusing unit 410 is disposed corresponding to the first reflecting mirror 2, and the second focusing unit 420 is disposed corresponding to the second reflecting mirror 3. The present embodiment sets the first focusing unit 410 and the second focusing unit 420 to focus two light beams, respectively, and more conveniently adjusts the defocus amount of the light beams and the corresponding spot size.
In the present embodiment, the first focusing unit 410 and the second focusing unit 420 are exemplarily shown to have one convex lens, but it should be understood that the specific structures of the first focusing unit 410 and the second focusing unit 420 can meet the performance requirement of focusing, and the arrangement of the specific optical elements is not limited to the embodiment shown in the drawings.
In some embodiments, referring to fig. 4, the first reflecting mirror 2 is provided in plurality, the plurality of first reflecting mirrors 2 are distributed around a preset axis 12, the preset axis 12 is parallel to the mirror surface of each first reflecting mirror 2, the diameter of the light transmission area 6 on each first reflecting mirror 2 is different, and therefore the initial light beams 5 with different diameters can be adapted without disassembling the first reflecting mirrors 2; meanwhile, in order to realize switching between the plurality of first mirrors 2, each first mirror 2 is mounted to a rotary switching mechanism.
On the basis of the above embodiment, referring to fig. 4, the specific arrangement of the rotary switching mechanism is as follows: each first reflecting mirror 2 is attached to the outer circumferential surface of an annular (or semi-annular) connecting frame 13, and the connecting frame 13 is disposed coaxially with the predetermined axis 12 and is pivotally connected to the main body of the apparatus with 12-position of the predetermined axis. A plurality of deflector rods 14 are arranged on the inner ring of the connecting frame 13 at intervals along the circumferential direction, and the deflector rods 14 correspond to the first reflecting mirrors 2 one by one; the inboard of link 13 is equipped with and rotates the shifting block 15 of being connected with the device main part, and the both sides face that shifting block 15 moved the end is the arcwall face, and two arcwall faces can contact with driving lever 14, are stirred by shifting block 15 when shifting block 15 rotates then. Wherein, a plurality of first speculum 2 are concentrated on one side setting of link 13, avoid other first speculums 2 influence light after the switching to pass through.
Fig. 4 shows a state where the dial 15 is rotated clockwise to a state of being separated from the rightmost dial 14, and the middle first reflecting mirror 2 faces the laser generator 1; if the shifting block 15 continues to rotate clockwise, the middle shifting lever 14 is shifted, so that the first reflector 2 on the left side in the figure gradually rotates towards the position opposite to the laser generator 1. The process of counterclockwise rotation of the dial 15 is similar and will not be described in detail herein.
In the present embodiment, the connecting frame 13 is exemplarily configured to be semi-annular, the main body of the device is provided with an annular rail 17, and the connecting frame 13 slides on the annular rail 17, so as to realize the rotation around the preset axis 12. In addition, an elastic damping component is arranged between the connecting frame 13 and the annular rail 17, so that the position stability of the connecting frame 13 can be kept under the condition that the connecting frame is not shifted by the shifting rod 14.
More specifically, referring to fig. 4, the two arc surfaces are respectively attached with an inductive patch 16, and the inductive patches 16 can sense the pressure between the shift block 15 and the shift lever 14; when the shifting block 15 pushes the shifting lever 14, the sensing patch 16 feeds back (in a wireless transmission mode) a first level signal to the control unit, and the control unit judges that the first level signal is in a pushing process at the moment; when the stirring is finished, the sensing patch 16 releases the pressure and feeds back a second level signal to the control unit, and the control unit judges that the time is in the intermittent time period. Wherein one of the first level signal and the second level signal is a high level signal, and the other is a low level signal.
In the arrangement of fig. 4, when the device is turned on, the first reflector 2 is hard to determine which is directly facing the laser generator 1, so that the dial 15 rotates clockwise continuously, and the sensing patch 16 located above in the figure can contact with the dial 14. In the rotating process, the signal fed back by the induction patch 16 is switched from the first level signal to the second level signal, and then one-time shifting is judged to be finished; switching the signal fed back by the sensing patch 16 from the second level signal to the first level signal, and judging that the next toggle knot starts; the time period from the end of the last dialing to the start of the next dialing is an intermittent time period which has a certain duration; if in the process of clockwise continuous rotation of the shifting block 15, after one-time shifting is finished, the next shifting is delayed without being started (the time length of the intermittent time period is exceeded), the first reflector 2 which is the leftmost reflector and is directly opposite to the laser generator 1 at the moment is judged, then the initial basis for adjusting the positions of the three first reflectors 2 relative to the laser generator 1 is provided, and the process is a pre-judgment process.
It should be understood that the counterclockwise rotation of the dial 15 can also complete the pre-determination process, and the principle is similar to the above-mentioned clockwise rotation determination principle, and is not described herein again.
This embodiment need not operating personnel macroscopic observation, also can be accurate provide the initial foundation of 2 position control of first speculum, convenient operation, and the accommodation process is more accurate swift.
Based on the same inventive concept, the embodiment of the application further provides laser welding equipment, which comprises a workbench and the laser welding device; the workbench is used for fixing a workpiece 7 to be welded, and the laser welding device is arranged on the workbench and can move relative to the workpiece 7 along a preset path.
In particular, the laser welding device can be moved relative to the table, or the workpiece 7 can be moved relative to the table.
Compared with the prior art, the laser welding equipment provided by the embodiment can perform better laser welding operation between dissimilar metals fixed on the workbench by adopting the laser welding device, and can effectively weaken the influence caused by the difference of thermophysical properties between the dissimilar metals.
In some embodiments, the laser welding apparatus further comprises a shielding gas mechanism and a powder feeding mechanism; the protective gas mechanism is arranged on the workbench and used for conveying protective gas to a specified position; the powder feeding mechanism is arranged on the workbench and used for feeding solder to a specified position. The shielding gas mechanism in this embodiment is used for conveying shielding gas to the surface of the workpiece 7, and the powder feeding mechanism is used for laying solder (or cladding material) at the butt seam 10 before welding, so that the automation degree of the equipment is improved.
Based on the same inventive concept, the embodiment of the application also provides a laser welding method, which is realized based on the laser welding equipment and comprises the following steps:
acquiring a laser power parameter and a welding speed parameter according to preset parameters of the workpiece 7;
acquiring the spot distance between a preheating spot 8 and a welding spot 9, and adjusting the included angle between the light beam reflected by the first reflecting mirror 2 and the light beam reflected by the second reflecting mirror 3, the defocusing amount of the preheated laser beam and the defocusing amount of the welded laser beam according to the spot distance;
and welding along a preset path according to the welding speed parameter, wherein the preset path is a butt joint seam 10 of the workpiece 7.
Wherein, work piece 7 predetermine the parameter and include material parameter, thickness parameter, and different materials are different to the absorptivity of laser, therefore different materials should select suitable laser power in order to satisfy the welding demand, and laser power is big more, and energy density is high more, and the facula diameter that forms is little, and defocusing amount is close to zero more simultaneously, and the facula size is little.
Compared with the prior art, the laser welding method provided by the embodiment has the advantages that the parameters are convenient to select, the welding process is simple, the preheating effect is better, the welding quality is higher, the method is suitable for butt welding operation among dissimilar metals, and the applicability of the laser welding process is improved.
In specific implementation, the defocusing amount of the laser beam for preheating is adjusted by adjusting the position of the first focusing unit, and similarly, the defocusing amount of the laser beam for welding is adjusted by adjusting the position of the second focusing unit.
In some embodiments, acquiring the spot separation of the preheating spot 8 and the welding spot 9 specifically includes: the spot pitch is obtained from the thickness of the workpiece 7.
Note that the spot pitch is a pitch between the center position of the preheating spot 8 and the center position of the welding spot 9.
In some embodiments, adjusting the reflection angles of the first mirror 2 and the second mirror 3 according to the spot pitch specifically includes:
according to a formula
Figure BDA0003528606490000111
Acquiring an included angle between a light beam reflected by the first reflecting mirror and a light beam reflected by the second reflecting mirror;
wherein θ is an included angle between the light beam reflected by the first reflector 2 and the light beam reflected by the second reflector 3;
L0is the spot spacing;
L1the distance between the center point of the reflection area of the first reflector 2 and the center point of the reflection area of the second reflector 3;
L2is the vertical distance from the center point of the reflecting area of the first reflecting mirror 2 to the surface of the workpiece 7.
In some embodiments, obtaining the welding speed parameter from the preset parameter of the workpiece 7 specifically comprises: and acquiring a welding speed parameter according to the thickness of the workpiece 7. Wherein the thickness is inversely proportional to the welding speed parameter.
In some embodiments, before welding along the preset path according to the welding speed parameter, the method further comprises: protective gas is introduced from the side of the workpiece 7. In the embodiment, the space around the workbench is fully utilized in a lateral ventilation mode, so that the design difficulty of the protective gas mechanism is reduced; meanwhile, the protective gas can be diffused in the welding area quickly, volatile gas generated by welding can be brought away from the welding seam 11 quickly, and the welding quality is improved.
In some embodiments, before welding along the preset path according to the welding speed parameter, the method further comprises:
fully polishing the surface of the plate body 710 to remove surface oxides and oil stains;
heating the workpiece 7 to a preset temperature, and keeping the workpiece 7 at the preset temperature for a preset time; the preset temperature is not lower than the vaporization temperature of the water.
This embodiment makes the moisture evaporation on work piece 7 surface through the intensification, avoids influencing the welding effect. The preset temperature can be actually set to be 120-150 ℃, and the preset time is about 1 h.
In some embodiments, after welding along the preset path according to the welding speed parameter, the method further comprises: the surface of the workpiece 7 is ground.
The laser welding method is suitable for various welding scenes, and is exemplified as follows:
1. general welding scenario
1) The welding process comprises the following steps:
A. polishing the plate body 710 to remove surface oxides and oil stains, heating the plate body 710 to 120-150 ℃, preserving heat for 1 hour to avoid the influence of moisture, and fixing the plate body on a workbench;
B. according to the material and thickness of the plate body 710, proper laser power and defocusing amount are selected to obtain a proper spot size;
C. adjusting the angles of the first reflecting mirror 2 and the second reflecting mirror 3 to achieve a proper light spot distance, and aligning the two welding guns with the workpiece 7 respectively;
D. introducing pure argon as a protective gas from the side surface of the workpiece 7;
E. and starting the laser generator 1 to emit laser beams and moving on a preset path at a certain scanning speed to form a welding seam 11 on the workpiece 7, thereby completing welding.
2) The welding parameter regulation and control comprises the following contents:
a. designing a welding process path
Before welding, the polished plate body 710 is clamped on a workbench, the butt joint seam 10 between the two plates is a welding seam position, and the gap of the butt joint seam 10 is preferably smaller than 0.2 mm.
b. Adjusting laser energy, defocusing amount and spot spacing
Before welding, determining laser power, defocusing amount and spot spacing according to the thickness and material of the workpiece 7; for example, the thickness of a plate is 0.1-2 mm, 0.4-1 kW laser power is adopted for welding, the defocusing amount of a hollow laser beam for preheating is + 3-5 mm, the defocusing amount of a solid laser beam is + 1-3 mm, the diameter of two light spots is 0.1-1 mm, and the distance between the centers of the two light spots is 0.5-1 mm; welding a plate with the thickness of 2-8 mm, and adopting 1-2 kW laser power, wherein the defocusing amount of a hollow laser beam is-3 to-5 mm, the defocusing amount of a solid laser beam is-1 to-3 mm, the diameter of two light spots is 1-2 mm, and the distance between the centers of the two light spots is 1.5-3 mm.
c. Controlling welding speed
Setting different laser scanning speeds according to different workpiece thicknesses, for example, the plate thickness is 0.1-2 mm, and the laser scanning speed is 65-75 mm/s; when the thickness is 2 to 8mm, the laser scanning speed is set to 35 to 45 mm/s.
d. Conditioning of shielding gas
The protective gas can be Ar gas, He gas or a gas mixed by the Ar gas and the He gas in any proportion, and the gas flow can be 15-30L/min.
e. Controlling weld formation
According to the detection of the appearance and the quality after welding, some parameter adjustments are made, and the laser power can be increased and the defocusing amount can be reduced when the welding is not completely welded; the welding through can properly reduce the laser power, increase the distance between two light spots and properly increase the defocusing amount.
3) In specific implementation, aluminum alloy 5052 and stainless steel 304 are butt-welded as an example:
carrying out butt laser welding on an aluminum alloy 5052 plate and a stainless steel 304 plate which are 150mm multiplied by 110mm multiplied by 1.5mm in size, cleaning the surfaces of a steel plate and an aluminum plate before welding to remove oil stains, and fixing the steel plate and the aluminum plate on a workbench in a butt joint mode; setting the laser wavelength to be 1070nm, the laser power to be 1000W, the welding speed to be 45mm/s, the defocusing amount of the hollow laser beam to be +3mm and the diameter of the light spot to be 0.6mm, the defocusing amount of the solid laser beam to be +1mm and the diameter of the light spot to be 0.2mm, and the distance between the two light spots to be 0.8 mm; the protective gas was pure argon gas, the flow rate was 15L/min, and the gas was blown from the side of the workpiece 7 at a blowing angle of 45 °. In the embodiment, two laser beams are separated by using the same laser source, and two metals are preheated in advance, so that the problem that the two metals cannot be simultaneously melted during welding due to the difference of melting points is solved, and the generation of an intermetallic compound Fe-Al can be reduced, thereby optimizing the performance of a welding joint.
2. Laser cladding scene
1) The welding process comprises the following steps:
A. fully polishing the plate body 710 to remove surface oxides and oil stains, heating the plate body 710 to 120-150 ℃, preserving heat for 1 hour to avoid the influence of moisture, and then fixing the plate body on a workbench;
B. pre-placing cladding materials, and pre-placing the cladding materials on the plate body 710 through a powder feeding mechanism according to requirements;
C. adjusting the angles of the two welding guns to obtain a proper light spot space, and aligning the welding gun head for emitting the hollow laser beam with a workpiece to be welded;
D. introducing pure argon protective gas from the side surface of the cladding surface;
E. starting a laser generator 1 to emit laser beams, moving the laser beams on a preset path at a certain scanning speed, and carrying out laser melting on a cladding surface; wherein the scanning speed can be set to be 10-15 mm/s;
F. and grinding the surface of the clad workpiece 7 to obtain a final finished product.
2) Welding parameter regulation and control is similar to the above scenario, and the main difference is that the following contents are included:
a. the cladding material is a powdery material, and the particle size of the powdery material is about 50-150 um.
b. Controlling cladding quality
According to the shape and quality detection after cladding, some parameter adjustments are made, the laser power and the spot diameter can be increased and the scanning speed can be reduced due to poor fusion.
3) In specific implementation, taking laser cladding of a single-channel cobalt-based alloy coating on a 42CrMo substrate as an example:
carrying out single-pass cobalt-based alloy laser cladding on a 42CrMo alloy steel substrate with the plate 710 size of 100mm multiplied by 12mm, cleaning, polishing and removing oil stains and oxides on the surface of the plate 710 before welding, heating to 120 ℃, drying, preserving heat for 1h and fixing on a workbench; the laser power is set to be 1500W, the defocusing amount of the hollow laser beam and the solid laser beam is +2mm, the diameter of each light spot is 3.5mm, and the distance between the two light spots is 4 mm. Presetting a cladding material at a designated position, wherein the diameter of powder is 50-150 um, the protective gas is pure argon, the gas flow is 15L/min, blowing in from the side at a blowing angle of 45 degrees, and opening a laser to clad at a scanning speed of 14 mm/s; and finally, grinding the surface of the clad substrate. The preheating process of the substrate can be reduced and the laser absorption rate in the cladding process can be improved by carrying out laser cladding, and the method has higher practical application value.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A laser welding apparatus, comprising:
the focusing device comprises a laser generator, a first reflector, a second reflector and a focusing mechanism;
the laser generator is used for generating an initial light beam;
the first reflector and the second reflector are sequentially arranged on the light-emitting side of the laser generator along the propagation path of the initial light beam;
the first reflector is provided with a light-transmitting area which is coaxial with the initial light beam, and the diameter of the light-transmitting area is smaller than that of the initial light beam;
part of the light rays of the initial light beam are reflected to the surface of the workpiece by the first reflector so as to form an annular preheating light spot on the surface of the workpiece; the light rays of the rest initial light beams penetrate through the light-transmitting area, and the second reflector reflects the light rays penetrating through the light-transmitting area to the surface of the workpiece so as to form a solid welding light spot on the surface of the workpiece; in the welding direction, the preheating light spot is positioned in front of the welding light spot;
the focusing mechanism is used for focusing the light reflected by the first reflector and the light reflected by the second reflector respectively.
2. The laser welding apparatus as claimed in claim 1, wherein the focusing mechanism includes a first focusing unit provided corresponding to the first reflecting mirror and a second focusing unit provided corresponding to the second reflecting mirror.
3. A laser welding apparatus, characterized by comprising:
the workbench is used for fixing a workpiece to be welded; and
the laser welding apparatus according to claim 1 or 2, provided at the work stage.
4. The laser welding apparatus as recited in claim 3, further comprising:
the protective gas mechanism is arranged on the workbench and used for conveying protective gas to a specified position; and
and the powder feeding mechanism is arranged on the workbench and used for feeding solder to a specified position.
5. A laser welding method implemented based on the laser welding apparatus according to claim 3 or 4, characterized by comprising the steps of:
acquiring a laser power parameter and a welding speed parameter according to preset parameters of a workpiece;
acquiring the spot distance between a preheating spot and a welding spot, and adjusting the included angle between a reflected beam of the first reflecting mirror and a reflected beam of the second reflecting mirror, the defocusing amount of the preheated laser beam and the defocusing amount of the welded laser beam according to the spot distance;
and welding along a preset path according to the welding speed parameter, wherein the preset path is a butt joint seam of the workpiece.
6. The laser welding method of claim 5, wherein obtaining the spot separation of the pre-heat spot and the welding spot specifically comprises:
and acquiring the light spot space according to the thickness of the workpiece.
7. The laser welding method of claim 6, wherein adjusting the reflection angle of the first mirror and the second mirror according to the spot separation distance specifically comprises:
according to a formula
Figure FDA0003528606480000021
Acquiring an included angle between a light beam reflected by the first reflecting mirror and a light beam reflected by the second reflecting mirror;
wherein θ is an included angle between the light beam reflected by the first reflector and the light beam reflected by the second reflector;
L0is the spot spacing;
L1the distance between the center point of the reflection area of the first reflector and the center point of the reflection area of the second reflector is set;
L2the vertical distance from the central point of the reflecting area of the first reflecting mirror to the surface of the workpiece.
8. The laser welding method of claim 5, wherein obtaining the welding speed parameter based on the predetermined parameter of the workpiece specifically comprises:
and acquiring welding speed parameters according to the thickness of the workpiece.
9. The laser welding method of claim 5, wherein welding along a predetermined path based on the welding speed parameter further comprises:
and introducing protective gas from the side surface of the workpiece.
10. The laser welding method of claim 5, wherein welding along a predetermined path based on the welding speed parameter further comprises:
heating the workpiece to a preset temperature, and keeping the workpiece at the preset temperature for a preset time;
the preset temperature is not lower than the vaporization temperature of the water.
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