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Laser welding white body excellent material processing heat source widely used

  Over the past decade, many of China's automobile manufacturers have begun to use laser welding, to carry out the white body of the welding. In the introduction of foreign technology - imitation - localization of the road, China's automobile manufacturers continue to break through heavy technical problems, accumulated their own experience and results.

  From the 1980s, the German Volkswagen factory took the lead in laser welding white body, the laser as an excellent material processing heat source in the automotive white body welding application more and more widely.
  On the white body in the use of laser welding the most common roof, side and back cover, in some European and American car factory has become a standardized processing technology. For example, the Audi car roof and rear trunk lid welding has been completely abandoned the spot welding, but also completely abandoned the spot for the big flange and seal for the groove design, and then use a shorter flange, material single method Blue docking design, while improving the body strength at the same time to meet the lightweight body, reduce the process steps to improve production efficiency requirements. With the European and American automotive manufacturers of laser welding technology mature use, white body laser welding is no longer a high-end welding technology.
  Over the past decade, many of China's automobile manufacturers have also started to use laser for white body welding, in Asia has been walking in front of Japan and South Korea cars. In the introduction of foreign technology - imitation - localization of the road, China's automobile manufacturers continue to break through heavy technical problems, accumulated their own experience and results. Such as JAC's large size, long-stroke sheet structure of the welding, is in the German car laser station on the basis of their own characteristics of the process after the conversion of the production run.
  Laser welding white body plate The most significant advantage is the energy concentration, welding speed. Different welding joints can be used in different welding processes, welding strength is also different. Here we first summarize the current car white body welding used in several major welding joints, as well as for these lap forms of welding process.
  The distinction between welding processes
  Laser welding with high power density, heating concentration, you can weld high melting point materials, weld width is small, good linearity, weld technology strength is relatively high and so on. The disadvantage is that the weld is easy to corrode, the welding hole stability requirements are high, the welding parameter adjustment range is small, the weld defect rate is very high, the weld surface is uneven, need to follow the grinding process.
  The advantages of laser brazing is that the laser energy at the end, heat and body deformation is small, can weld complex geometries, galvanized layer burning less, welds should not be corroded, welding parameters adjustment range, less welding splash, welding state stability , Weld defect rate is very low, weld appearance, after welding only need to deal with even without treatment. In the absence of welding defects under the premise of welding welding compared to the strength of the weld is slightly lower, laser brazing on the welding wire and spot and the relative position of the three parts of the high precision requirements.
  Weld Lap
  White body is currently widely used in the weld overlap include: double / multi-layer overlap overlap, fillet weld, flange butt weld. Different body parts are currently used in different lap, mainly due to the base metal material, weld strength, appearance and welding costs and other factors to consider.
  Double / multilayer overlap
  At present, the most used in the form of welding joints, mainly used for automotive A, B, C column, the end of the car, side fence, fender and other parts. This splicing method mainly uses laser deep welding, welding precision is low, the formation of high weld strength, equipment, low prices, simple operation. However, in the galvanized sheet and the surface with oil and water material, due to galvanized layer and water and oil evaporation easily formed pores or even through holes and other welding defects. Most of the need to anchor the plate before welding, so that the formation of gaps between the plate, easy to discharge volatile gas. The gap between the plates to ensure that between 0.2-0.3 mm, the gap is too small exhaust effect is poor, the gap is too large weld prone to collapse, which is very demanding on the accuracy of the equipment, and increase the production process, reduce production effectiveness.
  In order to improve the welding speed, there are a variety of flying laser welding head on the market, the welding of the weld stitching are double superimposed.
  Fillet welds
  Mainly used for door frame, window frame, after the trunk lid and other parts. This type of splicing welding site is located in the upper section of the cross-section, the welding site galvanized layer, oil and water volatile gas has enough emission space, weld quality to a large extent to improve. Brazing and welding can be used. But the laser spot needs to accurately act on the welding point, positioning is extremely difficult, so in the initial laser welding, the use of this way not much     splicing.
  Another advantage of the fillet weld relative to the double / multilayer lap is that the flanges are shorter and are increasingly being used in the current trend of lightweight body.