Welding method

      1. The resistance welding

Resistance welding is the workpiece after combination through the electrode pressure, using the current through the joint interface and the resistance of the heat generated in the vicinity of welding method, is widely used in automotive manufacturing. Resistance welding is used for welding industry complex joints, such as bumper, instrument panel, plastic pipe joint, container, etc. In spot welding process, the influencing factors on the quality of the solder joints are: welding current, welding pressure, electrode end shapes, across the electrodes of ferromagnetic material and shunt. Especially in the resistance welding equipment more welding workshop, mutual induction welding machine working at the same time, the impact on power grid, leading to poor stability of the welding quality and consistency. As a result, the resistance spot welding control technology is particularly important. Today, the development of control mode has been controlled by a single model for multiple model control, single variable adjustments of the adjustment parameters has been developed from the initial adjustment, developing multiple variables at the same time in the process of welding was carried out on the welding current, welding time and welding pressure adjustment.

    2. Gas shielded welding

Plus gas was used as medium and protect arc arc arc welding and welding area, referred to as "gas shielded welding. CO ₂ gas shielded welding as a kind of efficient welding method, with its characteristics of small welding deformation and welding of low cost, won the widely use of auto industry in our country. But CO ₂ gas shielded welding still exist some problems in practical application, the most widely applied in the CO ₂ gas shielded welding short-circuit transition form, for example, arc voltage, welding current and welding loop inductance mismatch, or wire stem elongation is not appropriate, can cause the welding arc stability, spatter and lack of penetration, etc., to have great influence on the mechanical properties of the weld, the weld. In addition, the short circuit transition welding on the dynamic characteristic of welding power source is very demanding. If the selection of error, the parameters of the welding arc range is narrow, can affect the quality of welding. Which have influence the quality of automobile production.

　　3. The laser welding

Laser welding is considered to be one of the most promising manufacturing technology in the 21st century. Laser welding is the use of laser stimulated the laser beam, by focusing on system and focus to the weld joint, converts light energy into heat energy, melt metal forming joint. Compared with the traditional spot welding, laser welding in the welding precision, efficiency, reliability, automation, lightweight and cost reduction, etc., has the incomparable superiority. Laser welding is the use of laser stimulated the laser beam, by focusing on system and focus to the weld joint, converts light energy into heat energy, melt metal forming joint. Compared with the traditional spot welding, laser welding with high precision flexible combination fixture in welding, efficiency, reliability, precision, automation, lightweight and cost reduction, etc, has incomparable superiority. Laser welding is considered to be one of the most promising manufacturing technology in the 21st century. Laser welding equipment is the key to high power laser, at present there are mainly two categories, one is solid state laser, the main advantage is that the light beam can be transmitted through optical fiber, suitable for flexible manufacturing system or remote processing. Another kind is gas laser, also called CO ₂ laser, with molecular gas as working medium, can work continuously and high output power. In the automotive industry, laser technology is mainly used for automobile body welding and welding parts, such as roof and side welding. But the laser welding for welding assembly precision, and the location of the beam on the artifacts are requested not to have a significant deviation. Otherwise it is easy to cause weld defects. Laser welding in automobile industry, especially in the production of high-grade car has become a standard technology, such as Volkswagen Golf production in the aspects of welding length: laser welding is 52.5 m; Use the same source of laser brazing seam is 3.6 m; Adhesive joint is 22.6 m; The arc welding is 4.7 m; Spot welding is 2938. According to the contribution of calculation for car body structure as a whole, the proportion of laser welding and spot welding each accounted for 45%, far more than other connection methods, laser welding and flexible combination welding jig has been in the field of automobile manufacture made indispensable process and equipment.

Represented by laser welding of pure quantitative welding production methods with a new concept of technology promote the progress of the auto welding technology. In addition, some new connection method is also the first application in automotive manufacturing. Such as variable polarity MIG/MAG welding method, laser, arc composite magnetic pulse welding method, welding method, bonding and mechanical connection methods have already been successfully used in the manufacture of all kinds of new models. Make the car production quality greatly improved.

　4. The intermediate frequency welding technology

Intermediate frequency inverter dc welding machine is (50 Hz) power frequency ac transform into intermediate frequency (thousands of Hz) dc output, time resolution is higher than the power frequency and high control precision, and the output current is not affected by secondary output circuit, high thermal efficiency, output power is very big, the welding quality is better. And traditional power frequency welder, solder joint instability, high energy consumption of the large welding spatter, welding quality is relatively poor disadvantage compared to intermediate frequency welder has good welding quality, high control accuracy, high welding speed, energy saving effect is obvious, the equipment volume and weight of relatively small, can be widely spot welding of dissimilar metals, energy conservation, environmental protection and other excellent features. In recent years, foreign auto parts production batch big enterprises, have intermediate frequency welding technology was applied to car white body welding line. In Europe, the middle frequency spot welding robot use has accounted for 40%, and extended to the aluminum alloy car body welding operations.

Domestic such as faw Volkswagen, also basically use intermediate frequency spot welding equipment, truck production line is still no large-scale application. Due to intermediate frequency inverter welding machine has advantages of high efficiency and energy saving, advocate energy conservation and environmental protection low carbon life in the world today, should actively adopt intermediate frequency welding technology in automotive manufacturing. In the future have a decisive role in the production of cars.

　5. Robot welding technology

Robot welding technology in the modern welding technology also plays a decisive role in the automobile production. Welding production line is composed of welding equipment, fixture, transmission system and automatic control, etc. As a result, whole production line of flexible degree is decided by the flexible degree of each component. Welding equipment of flexibility is the key to the flexible degree determine welding production lines, flexible degree of jig is welding production lines, the main factors and the flexible combination jig used is decreased jig.

Body welding line of welding equipment are mainly manual welding equipment, automatic welding machine and welding robot. Manual welding equipment mainly include hanging spot welding machine, semi-automatic CO ₂ gas shielded welding machine, etc., they all belong to the universal standard equipment. By manual operation to complete the welding work, its independence is stronger, ease of installation, adjustment and maintenance, and the price is low, so in every era in the development of production has been widely used. Automatic welding machine, including a multipoint welder, desktop automatic welding machine and all kinds of welding manipulator, the special plane complex structure, simple action, basically fixed, the manufacture cost and maintenance cost is high, applies only to a certain kind of welding products, flexible degree is low. Therefore, only on a single variety, used in the welding production line of mass production, before, generally in the annual production program is used on the production line of more than 60000 vehicles, now only more annual production capacity of production line to be considered. Welding robot is independent of ontology, the degrees of freedom of action, more flexible degree application change flexible, high automatic degree, high welding equipment. Has the multipurpose function, high repeatability, high welding quality, fetching large weight, movement speed, movement characteristics such as stable and reliable, welding robot is the best choice of the welding equipment flexibility. Welding equipment as an important part of the welding production line, whether to adopt the welding robot is an important symbol of flexible degree of welding production line. Automotive mass, high efficiency and the consistency of the quality of product requirement, make production mode in auto welding robot is obtained in a large number of applications. Modern welding technology played a pivotal role in auto production quality!

　　Automobile industry is worldwide industry, auto industry as a pillar industry, its every development, progress, is inseparable from the support related science and technology, industrial development. With the development of China's automobile manufacturing, welding technology made great progress, but compared with developed countries of automobile industry there is great gap. Face international competition globalization, the internationalization of domestic competition situation, in order to make our country automobile industry to gain a foothold in the development of world automobile industry, only rely on, including welding technology, the improvement of manufacturing technology progress and innovation ability, to achieve the goal of China's auto industry development.

When China from "made in China" to "created in China", there will be more Chinese independent brand of flexible modular fixture for the cognitive world. Flexible combination fixture as supporting the development of the auto industry giants, vibrant, with the spirit of national industry will move towards the world and the industry towards a brilliant!