Resistance spot welding car body manufacturing is considered the most important connection process. Despite the laser beam welding and adhesive bonding and other new technologies, but spot welding in automotive body manufacturing will still retain its strong position. Because many factors affect the processing quality of spot welding, spot welding quality standards and demanding, it is necessary to systematically examine the quality of spot welding joints.
    To this end, the past practice is the use of invasive tests for random testing. Because of this approach has some drawbacks, such as: will destroy or distort the test sample, the test for a long time, in the process of hammering can damage and loose parts, when using "zinc binder" when using the method of hammering can not find the bonding point, so it is not suitable for modern manufacturing technology and cost accounting sense. Here is a remedy - "point-line ultrasonic testing method", using this method, the welding process can be carried out spot checks.
    "IQR System" is the quality of resistance spot welding process in online testing and optimization of a new control technology
    This method can use the U-I characteristics in the evaluation of compensation Zinc oxide on the basis of changes in some parameters control interference, such as changes in plate thickness, coating thickness changes, changes in electrode wear wear and tear. As simple, IQR controller to ensure stable and reliable high-quality welding, and saves time and costs.
    In the resistance spot welding field, one can clearly see the use of welding equipment in the servo motor drives a clear trend. In 2001 the International Essen Welding Fair, no less than 12 manufacturers demonstrated the use of servo motor drive technology of welding equipment (installed in the micro-spot welding, manual and robotic welding torch and spot welding on a pedestal .) According to expert forecasts, the welding quality and welding cycle is shorter, so the air will be more and more welding equipment, servo-driven welding equipment being replaced. In addition, some manufacturers use air-cooled torch display servo motor drive, the electrode force and welding required cycle time requirements of the welding tasks with a wide range of applications.
    Welding head with a tiny spot of piezoelectric linear drive unit, with the ideal characteristics of the re-set parameters, and can easily move the line programming. Because of its strong and stable mechanical structure and the use of a piezoelectric drive technology, so that the time required for positioning before and after welding is very short. Therefore, we can seize the opportunity to work cleaning up from the stage of phase transition to work, welding power savings. As the agency with a strong and dynamic high performance drive system, the torch electrode is more suitable for automatic welding equipment, welding efficiency is high.
    Punch riveting and spot welding method for the ordinary torch, Titanium dioxide speed and precision in the movement are more demanding challenge of the high productivity of the robot. In order to reach a larger scope of work, while bending the least, through careful design and development of a new generation of robot welding torch to create materials with a structure very light carbon fiber reinforced plastics (CFRP). According to research, has been carefully optimized to create a test sample torch. Recently developed to strengthen the structure of a very strong vertical bending arm and can provide a powerful reaction, even through the online control of the angle of offset compensation. Applications for the people of this further development of modern fiber materials better light structure potential.
    Use of laser technology and laser beam processing of materials
    Although the power over the 12mm × mrad4kW Nd: YAG solid-state laser beam of high quality, it is impossible to achieve the breadth of CO2 laser applications. It is because of the cost of using CO2 lasers and maintenance costs are lower, so it can be widely used.
    For example, 3kW of laminar flow CO2 laser can work around 40000h, the cost per hour of work about 6 marks. The laser power CO2 laser with an ordinary half, in 1.5m/min welding speed constant, almost able to achieve the same weld penetration depth. When the welding of steel penetration depth of 4mm, the same as when the laser beam power, Nd: YAG solid-state laser welding speed is only half the CO2 laser.
Only in three-dimensional multi-axis articulated arm robot, when using the Nd: YAG laser was lower than the total investment in the case of CO2 lasers because the optical fiber by Nd: YAG laser beam transmission is relatively simple.
In remote welding, CO2 laser beam focused through the lens, the optical scanner system, the laser beam can be freely positioned on the workpiece surface. Electric focusing lens mounted on a rail, you can 1500mm × 1500mm × 400mm space to determine the processing point. Use mobile mirror device can be extended to interfere with the back edge of the solder joints.
    The laser beam welding and arc welding processes can be combined to Magnesia obtain a welding process is worth noting: the CO2 laser beam with the gas metal arc welding process of combining great process. Adopt the technology, to the different levels of high-efficiency steel welding. The purpose of using this process is to determine the different thickness of steel plate for welding when the maximum gap width amax. In the plate thickness t = 5mm, the gap width of 2mm; when t = 8mm, the width of 1.35mm; when t = 12mm, the width of 0.7mm. Welding process in the formation of gravity state, without any support molten weld behind. 20mm thick steel plate in the horizontal welding, the gap width asssmax can overlap up to 0.7mm, without any technical problems. Optimum set also includes other aspects of welding and welding wire feed speed and wire diameter selected.
    People of this modular welding process was tested, and in the actual welding work is demonstrated. For example, in the Meyer shipyard, successfully welded a few 7.5 ~ 12mm thick, 10m long steel, welding speed 2m/min. In the above combined welding process, the combination of the arc can be increased to further enhance the advantages of the process, for example, the energy per unit length to minimize, to improve welding speed and lap joint space capabilities.
    A structure strong compact, easy-to "tools" of the diode is excited Nd: YAG laser and the quality of the laser beam. Thermal lens effect limits the improvement of beam quality, the goal is to further improve the beam parameters to further improve, and enter it into 100μm glass fiber, so you can get the beam quality comparable with a CO2 laser beam.
    Here is a more promising and laminar flow-type laser disc laser. In 2001, laser technology exhibition, HASS laser technology company for the first time demonstrated the prototype of the laser disc. Display prototype laser power 1.3kW, optical fiber diameter of 0.15mm. Light excitation and rod-type laser diode excitation laser beam power caused by the existence of thermal lens problem, and disc laser thermal lens effect is no longer the issue. As the disc laser and CO2 laser beam with similar beam quality by fiber coupling method can be calibrated to change its power than the power calibration of the laser rod is many times larger.
    With output power greater than 4kW diode laser excitation of solid, aluminum welding for the decisive significance. These systems are particularly good beam quality can be instantly injected into the fiber diameter of 0.4mm. Ability to focus Barium titanate the laser beam greatly depends on the fiber cross-sectional area. This indicates that the potential of a new generation of solid-state lasers is the "point" smaller diameter, higher power density. High power density allows people to carry out a continuous wave mode welding. For example, first used for small samples and small parts of various connections, such as docking, T-shaped welding and bonding were studied. Parts of the material is AlMgSi0.7 (thickness: 3mm) and AlMg3 (thickness: 1.6mm) aluminum. High-quality weld shape only in the pure continuous-wave state is possible. When using the kilowatt-class diode excitation of the Nd: YAG laser welding of aluminum, in a wide range of parameters can be very high reliability.
    Literature also describes the impact of a quality weld geometry and the new method. This is based on the impact of electromagnetic force in the pool, the pool to produce different flow and heat input. This would have a choice to change the shape of the weld, the penetration depth, weld bead shape and reduce the formation of pores.
    When a laser beam processing pipeline, lining the inner surface of the cylinder and, even in very limited specific surface also change the properties of the materials. Laser beam can provide a precise control of energy, in a particular place and time to exert energy, usually only a very small error, so no or only a small amount of post-processing. In industrial applications, this tool is fitted with a protective facilities, such as the use of pressure. Chamber and horizontal jet (Cross-Jet) to protect the optical system, the cooling method with dissipation of the absorbed laser radiation, plasma radiation and with the thermal radiation.
   Lasers include the following components: laser adapter, matrix and laser head. Matrix can be mechanically connected by the laser processing system to determine the required processing and media. In the base body, through the optical means to provide for the laser head and laser radiation. If necessary, you can also install a brush with the media campaign with the device, the laser head for rotary movement. Built laser beam to form a central element (bronze mirror coating) and protective gas or processed gas nozzle. The power of 2kW Nd: YAG laser is also connected on a long rail for hardened devices. Integrated mirror Nickel oxide group work in distance of about 60mm focus the beam to 3mm × 5mm. 3kW power solid-state lasers used can harden φ60mm, deep 600mm high steel bushings. In addition, the development pipeline for the hardening of the internal optical system has a rotating laser head, the engine can be fixed on the body work done, for the hardening of gray cast iron diesel engine truck engine block cylinder block bearing surface.
    A newly developed plasma arc welding for the moment the system, using reverse polarity electrode and the selection of 100 ~ 200A welding current can be cost-effective welding of aluminum parts, good quality welding. The welding of various aluminum-magnesium alloy test showed that: in the welding 2 ~ 8mm plate, you can use and melt into the keyhole welding technology.
    Variable using the electrode polarity plasma arc keyhole techniques can be used to weld circumferential welds, such as AlMg3 pipe, flange, and GK-AlSi7Mg cold-cast alloy of the shapes of parts, materials thickness can be 8mm non-groove butt weld. Using a newly developed special gas control system can be completed without defect circumference weld finishing welding. Since only one side will produce porosity in the casting, so to determine the casting molten metal atomic hydrogen content. If casting the molten metal in the hydrogen content is lower than 0.3mL/100g, weld porosity produced very little. With this method the total length of weld to be repaired up to 39m, accounting for 27.2% of the weld length.
    In research and development of power and control of the most modern technical conditions, the use of plasma arc technology is a best quality, cost-effective, reproducible connection process. In addition, by adjusting the current, Neodymium fluoride to ensure thick butt joint welding, plasma arc generated when the keyhole of the sensor system, the pool conductive support and welded plate insulation, and by the charged plasma arc through the frame when the measuring current, and with the the move.
    This new technology and TIG welding compared with the following characteristics:
    (1) when the plasma arc welding process-specific advantages, not only mainly in the micro-plasma arc welding of plate thickness in the range, and involves the use of keyhole techniques.
    Applications include: Surface welding, spraying and welding. Adjustable frequency through the use of low pulse welding current, arc welding, plasma arc can better control the size of the energy, modern control systems through synchronization and reliable monitoring of the implementation of a variety of settings. Welding power transistors, such as AUTOTIG series, you can accurately run in accordance with the provisions of technical specifications.
    (2) with the powder plasma arc welding sheet metal and pipes, with a welding speed, heat input and deformation of small advantages.
    (3), plasma arc welding, the keyhole technique has clearly demonstrated the advantages of 10mm thick plate welding material.