CN110614439A

CN110614439A - High-reflectivity material laser connection method and device

Info

Publication number: CN110614439A
Application number: CN201910814447.5A
Authority: CN
Inventors: 胡文景; 叶云霞; 李琳; 周王凡; 任旭东
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2019-12-27

Abstract

The invention relates to the field of laser texture and laser welding, in particular to a laser connecting method and device for high-reflectivity materials, and specifically comprises a laser texture device and a laser welding device. The laser connection of the high-reflectivity material mainly comprises two steps: firstly, local laser texturing is carried out on the area to be connected, and secondly, laser welding is carried out. The method has three main advantages: firstly, the laser absorption efficiency of the surface of the high-reflectivity material is improved through laser texture, and a molten pool is easily formed in a texture area in the subsequent laser welding process; secondly, preheating a surrounding non-texture area of a texture area which is easy to form a molten pool through heat conduction, enhancing the absorption of the non-texture area to laser and improving the weldability of the non-texture area; and thirdly, the welding process is optimized and the laser connection efficiency is improved through the active design of the length, the width and the distribution of the texture area.

Description

High-reflectivity material laser connection method and device

Technical Field

The invention relates to the field of laser texture and laser welding, in particular to a method and a device for realizing high-efficiency and high-quality laser welding high-reflectivity materials.

Background

The development of modern new energy industry and microelectronic industry has more and more vigorous demand on high-quality and high-reliability high-reflection material welding joints of pure copper, aluminum/aluminum alloy and the like. The existing welding technologies include ultrasonic welding, resistance spot welding/projection welding, micro Tungsten Inert Gas (TIG)/pulse arc welding, ultrasonic wedge pressure welding, micro riveting, magnetic pulse welding, laser welding, mechanical fastening, and the like. Compared with other connection technologies, laser welding has the characteristics of high speed, low heat input, non-contact and easiness in automation, so that the welding method has unique advantages in the field of new energy industries with higher requirements on quality, efficiency and automation degree. However, the high-reflection material has high reflectivity to laser beams with common wavelengths and strong self-heat conductivity, so that the high-reflection material is a well-known laser difficult-to-weld material.

In order to improve the laser welding performance of these materials, the singapore scholar, Hui-Chi Chen et al, in the article "Enhanced welding efficiency in laser welding of high purity reflective purecopper," proposed a method for coating the surface of pure copper with a copper-based nanocomposite absorption layer before welding, so as to improve the absorption efficiency of pure copper to laser. Although the scheme can effectively improve the absorptivity of the pure copper surface to laser, the absorption coating can change the electromagnetic performance of the pure copper welding joint. In the text of the influence of preheating before welding on the structure and performance of a T2 pure copper laser welding joint, how best et al propose a method for preheating pure copper before welding to improve the absorption efficiency of pure copper on laser, but the effect is not satisfactory.

Disclosure of Invention

Aiming at the defects or shortcomings in the prior art, the invention provides a high-reflectivity material laser connecting method and device based on laser texture and laser welding compounding.

In order to achieve the purpose, the invention adopts the technical scheme that: a high-reflectivity material laser connection method comprises the following steps: s1: carrying out local laser texturing on the area to be connected; s2: and carrying out laser welding on the areas to be connected.

In the above scheme, in step S1, the width of the local laser texture region is greater than the diameter of the welding spot, and is symmetrical along the center line of the weld.

In the above-described embodiment, in step S2, when the laser welding is performed on the region to be joined, the laser welding line is inclined at a predetermined angle.

The invention also provides a high-reflectivity material laser connecting device which comprises a laser texture device and a laser welding device, wherein the laser texture device comprises a first working platform, a first clamp for clamping a pattern is fixed on the first working platform, and a first argon protection device is arranged around the first clamp for clamping the pattern; a first laser generating device is arranged above the first workbench, the first laser generating device is fixed on a support, and the support is connected with the lifting column through a ball screw; the laser welding device comprises a second workbench, a second clamp for clamping a pattern is fixed on the second workbench, a second laser generating device is arranged above the second workbench and fixed on a manipulator, and a second argon protection device is arranged around the second clamp for clamping the pattern.

In the scheme, the laser texture device and the laser welding device perform station switching through a rotary workbench or a production line type feeding mode.

The invention has the beneficial effects that: (1) the invention provides a method for improving the laser absorption efficiency of the surface of a high-reflectivity material by adopting a laser surface texture technology before laser welding and improving the laser weldability of subsequent materials. Experiments show that the laser texture can effectively improve the absorptivity of 1 micron laser to pure copper from 5% to 84%, and does not change the components of welding seams, namely does not influence the electrical performance of copper welding joints; (2) the method provided by the invention combines two technologies of laser texturing and laser welding, is easy to realize automatic control, and is pollution-free, green and environment-friendly; (3) the method provided by the invention only needs to texture the local area of the continuous welding area and does not need to texture the whole area. A molten pool is quickly formed by utilizing the high-efficiency absorption of a local texture area to laser, and a welding seam is formed in the area; meanwhile, the local texture area preheats the untextured area by utilizing the heat conduction effect, so that the absorption efficiency of the untextured area is improved, and the weldability and the weld quality of the untextured area are further improved. By the technical scheme, the time cost and the economic cost of the full-area texture are saved, and high-efficiency and high-quality laser welding is realized.

Drawings

Fig. 1 is a schematic view of a laser texturing apparatus provided by the present invention.

Fig. 2 is a schematic view of a laser welding apparatus provided by the present invention.

Fig. 3 is a diagram of 4 design concepts for textured areas.

FIG. 4 is an effect diagram of a pure copper welding seam welded in a fully-textured manner.

Fig. 5 is an effect diagram of pure copper welding seam welding with rear half texture.

In the figure: 1-1. a first working platform; 1-2. a second working platform; 2. a pattern; 3-1, a first argon protection device; 3-2, a second argon protection device; 4-1. a first laser generating device; 4-2. a second laser generating device; 5. a support; 6. a lifting column; 7. a robot arm.

Detailed description of the preferred embodiments

The technical solution of the present invention will be described in more detail with reference to the accompanying drawings.

The laser connection device for the high-reflectivity material comprises a laser texture device and a laser welding device, as shown in fig. 1, the laser texture device comprises a first working platform 1-1, a first clamp for clamping a pattern is fixed on the first working platform 1-1, and a first argon gas protection device 3-1 is arranged around the first clamp for clamping the pattern; a first laser generating device 4-1 is arranged above the first workbench 1-1, the first laser generating device 4-1 is fixed on a bracket 5, and the bracket 5 is connected with a lifting column 6 through a ball screw; the first working platform is connected with a first clamp for clamping a pattern through a bolt, the first clamp for clamping the pattern is used for clamping the pattern 2, the first laser generating device 4-1 is arranged in the support 5, the support 5 is connected with the lifting column 6 through a ball screw for transmission, and the lifting of the support 5 is adjusted through a rotating hand wheel for adjusting the defocusing amount; the controller is arranged above the cabinet, and the inside of the cabinet is provided with components such as an industrial personal computer, an electric wire and the like. When the device is used for laser texturing, the cabinet is moved to a proper position away from the workbench, the hydraulic column at the bottom of the cabinet is jacked up, the processing equipment is fixed, and the pattern is placed at a proper position on the first workbench; and starting the first laser generating device 4-1, and manually rotating a hand wheel on the lifting table to adjust the distance from the laser to the pattern to a proper position so as to control the defocusing amount. The controller designs a texture area program and controls the first laser generating device 4-1 to process the texture of the pattern 2.

As shown in fig. 2, the laser welding device includes a second work table 1-2, a second fixture for holding a pattern is fixed on the second work table 1-2, a second laser generator 4-2 is arranged above the second work table 1-2, the second laser generator 4-2 is fixed on a robot arm 7, and a second argon gas protection device 3-2 is arranged around the second fixture for holding a pattern. The distance between the second working platform 1-2 and the mechanical arm 7 is proper, the second working platform 1-2 is in bolt connection with a second clamp for clamping patterns, and the second clamp for clamping patterns is used for clamping a sample subjected to texture machining; the second laser generating device 4-2 is arranged on the mechanical arm 7 and can be adjusted in the direction of 360 degrees, the second argon protection device 3-2 is arranged on one side of the mechanical arm 7 through a screw, the interior of the second argon protection device is hollow, two copper pipes are communicated below the second argon protection device, one side of the second argon protection device is provided with a through hole, and the second argon protection device is communicated with an argon bottle through a soft leather gas pipe; a groove is formed in the working platform and is opposite to the lower portion of the welding line, one end of the groove is communicated with an inner hole, and the other end of the inner hole is connected with a soft tube to an argon bottle. Before laser welding, installing the sample subjected to texture processing, opening a second laser generating device 4-2, and introducing argon; and during welding, adjusting the welding parameters of the second laser generating device 4-2, and welding the sample. The laser texturing device and the laser welding device can be switched in stations by a rotary workbench or a production line feeding mode.

A high-reflectivity material laser connection method is characterized in that a texture must be implemented at an initial welding seam, and the length, width, shape, distribution and the like of a texture area can be actively designed; only carrying out laser micro-texture processing on the local position of the welding seam in an argon environment; the width of the local texture area is larger than the diameter of a welding spot and is symmetrical along the central line of a welding seam; according to the requirement of a processing beat, high-power and multi-beam lasers can be adopted to improve the texture efficiency; the laser is inclined at a certain angle during welding, so that strong laser is prevented from being reflected back along the inside of the laser to damage the laser; a sealing device can be designed, argon is introduced in a closed environment to cover a sample welding area, and the front surface and the back surface are protected by argon; the high-reflectivity material is a metal material with the reflectivity of more than 60% to laser wavelength with the wavelength of about 1 micrometer under the light-directing surface condition, and comprises pure copper, pure aluminum, alloy materials thereof and the like.

Example (b): the pure copper butt welding of 40X 0.5mm is taken as an example. Texturing was performed using a MOPA fiber laser marking machine, model JFMP 20. During operation, an operator pushes the laser platform to a proper position of a region to be worked, as shown in fig. 1, and then raises the hydraulic column to fix the whole device; fixedly mounting a sample 2 on a first working platform 1-1 by using a first clamp for clamping a sample; starting a power switch, turning on the first laser generation device 4-1, turning on a display, turning on software EzCad2, checking whether a laser of the first laser generation device 4-1 normally runs, and if so, carrying out the next step; the texture zone was designed using software, 4 examples are given in fig. 3, specifically making a recipe based on the materials and welding parameters; opening red light, adjusting the laser action zone to be positioned at the welding seam, rotating a hand wheel on the lifting column 6, and finding the focus position to enable the defocusing amount to be 0 mm; setting laser parameters (power 90%, scanning speed 50mm/s, frequency 20Hz, pulse width 50ns, line spacing 0.01 mm), clicking the working button, and performing laser texturing (specifically, refer to the four design modes of FIG. 3).

And after the texture is finished, taking down the copper sheet, and performing laser welding on the copper sheet in the next step, wherein the welding laser is a fast Trudisk6002 laser. As shown in fig. 2, a worker previously arranges the manipulator 7 and the second working platform 1-2 to a proper position, installs a sample processed by the laser microtexture, and opens the air pressure switch of the second argon protection device 3-2; starting a power switch of a second laser generating device 4-2, checking whether the laser operates normally, and if so, performing the next step; and programming the controller according to the welding parameters, and taking down the welded part after the welded part is cooled. The welding effect of welding the fully-textured copper sheet (parameters are 2700W, 15m/min welding speed, 13 degrees of incidence angle and 0mm defocusing) is shown in FIG. 4. Fig. 5 is a graph of the welding effect of welding the half-textured area, and it can be seen that the non-textured area also forms a weld, and the latter half has some porosity due to impurities.

Claims

1. A high-reflectivity material laser connection method is characterized by comprising the following steps:

s1: carrying out local laser texturing on the area to be connected;

s2: and carrying out laser welding on the areas to be connected.

2. The laser joining method for high reflective materials according to claim 1, wherein in step S1, the width of the local laser texture region is larger than the diameter of the welding spot and is symmetrical along the central line of the weld.

3. The laser joining method according to claim 1, wherein in step S2, the laser welding line is inclined at a certain angle when the laser welding is performed on the regions to be joined.

4. The laser connecting device for the high-reflectivity materials is characterized by comprising a laser texture device and a laser welding device, wherein the laser texture device comprises a first working platform (1-1), a first clamp for clamping a pattern is fixed on the first working platform (1-1), and a first argon protection device (3-1) is arranged around the first clamp for clamping the pattern; a first laser generating device (4-1) is arranged above the first workbench (1-1), the first laser generating device (4-1) is fixed on a support (5), and the support (5) is connected with a lifting column (6) through a ball screw; the laser welding device comprises a second workbench (1-2), a second clamp for clamping a pattern is fixed on the second workbench (1-2), a second laser generating device (4-2) is arranged above the second workbench (1-2), the second laser generating device (4-2) is fixed on a manipulator (7), and a second argon protection device (3-2) is arranged around the second clamp for clamping the pattern.

5. The laser connecting device for high-reflectivity materials of claim 4, wherein the laser texturing device and the laser welding device are switched by a rotary table or a pipeline feeding mode.