Development trends of welding automation and weldi

2022-08-20
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Development trends of welding automation and welding robots in Japan

development trends of welding automation and welding robots in Japan

information on China's construction machinery

Guide: welding automation and welding robots can provide stable welding quality, reduce workers' labor intensity, improve productivity and reduce costs, which have been the goals pursued by human beings in thousands of ways for several years. Japan has introduced the spot welding robot into the production line as early as the 1970s, and the arc welding robot is living because of its complexity

welding automation and welding robot can provide stable welding quality, reduce the load mechanism: it is composed of four parts: load device, load adjustment, force sensor and displacement sensor. The labor intensity of workers, improve productivity and reduce costs have been the goals pursued by human beings for several years. Japan introduced the spot welding robot into the production line as early as the 1970s, and the application of arc welding robot in production is much later than the former because of its complexity. However, by the 1980s, the use of arc welding robots in Japan began to increase significantly. At present, the spot welding robot is still mainly used in the automotive industry, and the arc welding robot has been widely used in various industries in terms of changing the angle of the clamp used for special samples (finished products and semi-finished products). In 1997, the output of arc welding robots in Japan reached 9333, and the output of spot welding robots was 8228. In particular, the application of arc welding robot has been widely used in automobile, ship, railway vehicle, boiler container, metal products, construction machinery, household appliances and other industries, which has played a significant role in reducing costs and improving quality. This paper briefly introduces some new technological achievements in the development and application of welding automation and welding robot in Japan

1 new CO2 welding power source to reduce spatter

in automatic MAG welding (gas shielded arc welding with consumable electrode), it is very important to reduce spatter so that the welding process can be carried out continuously for a long time. To this end, Kobe iron and Steel Company of Japan has developed a new CO2 welding power supply (SP500). This power supply is mainly composed of pulse modulated inverter, which is used to connect with arc welding robot. This power supply can control the current waveform at the moment of splash by detecting before the arc is re started or before the short-circuit transition, reduce the current and suppress the splash. The current during the short-circuit transition and the voltage during the arc combustion process can be adjusted independently to obtain the appropriate waveform. Therefore, this power supply has constant current characteristics when the short circuit lasts and the experimental results are printed or saved, and the effect of inhibiting splash is very obvious, especially the splash of large size (more than 28 eyes) can be reduced to about 1/5 of the conventional power supply

this power supply also has high arc striking reliability, which is very important for efficient and high-speed short joint robot welding. In order to rapidly ignite the arc at the beginning of welding, the current rise rate can reach nearly 3000a/ms, and a stable arc can be established within a few milliseconds. At the end of welding, the power supply can automatically adjust the current to minimize the residual droplet size at the end of the welding wire. This new type of power supply has been successfully used in automobiles, boiler containers and other industrial fields

2 new arc starting method of automatic TIG welding

the common arc starting method in TIG welding (tungsten inert gas arc welding) is contact arc starting or high-frequency voltage arc starting. Then these arc starting methods have some problems for arc welding robot system. The former may produce defects at the beginning of the weld and increase electrode wear, while the latter may produce high-frequency electromagnetic noise, which will interfere with the operation of the control computer, resulting in sudden unpredictable movement of the robot, and even trigger other equipment

in order to solve these problems, the Japan iron and Steel Association has developed a new TIG arc striking method. The principle of arc striking is illustrated in Figure 1: a generator with small power equal to ion flame flow (ignition plasma) is installed on one side of the main tungsten electrode. Its volume is very small (diameter 10mm, length 10mm), and argon is used as plasma gas. When the power is turned on, the plasma flame will be ejected on the tungsten electrode side, and a working arc will be established between the tungsten electrode and the workpiece within about 20ms. Compared with the contact arc striking method, this arc striking method has almost no electromagnetic noise, reduces electrode wear, is conducive to arc stability and reduces the possibility of defects

1. Main electrode

2 Nozzle

3 Pilot plasma generator

4 Connecting wire

5 Workpiece

3 multi pass robot welding system

with adaptive control, the multi pass automatic butt welding system has been successfully developed by Japan's Kobe Steel Company for supporting the use of fixed or mobile robots. In this system, seam tracking, yaw width control and weld bead height control are all automatic. In the lateral swing with constant arc length control, the return point of the welding torch in the groove is determined by the height of the welding torch reaching a constant preset value. The detected yaw width value is used to control the welding speed so that the weld height remains constant. Figure 2 shows the principle. In the initial state of root width G0, weld height H0, and deposition area A0, the yaw width is W0. If the root width changes from G0 to g, and the yaw width changes from W0 to W, assuming that the groove angle is constant, then

g-g0=w-w0 (1)

in order to keep the weld height constant, the deposition amount should be increased Δ A:

Δ A= (g-g0) h0= (w-w0) H0 (2)

the optimal welding speed V can be calculated according to the following formula:

v=vf/((vf/v0) + (w-w0) H0)

in the formula, VF --- wire feeding speed, V0 --- initial welding speed

Figure 2 also shows the control block diagram. The system has been successfully used in construction steel framework, bridge structure, vehicle, shipbuilding and other industries

4 pipeline automatic high-speed MAG welding method

automatic welding of pipeline installation usually adopts TIG, because this method is relatively easy to obtain a uniform and fully penetrated weld. However, TIG welding is slow and inefficient. In order to obtain high welding speed, Sumitomo Corporation of Japan has developed a fully automatic MAG welding method. The system has been successfully used in the welding of pipelines in tunnels and underground gas transmission pipelines. Short welding time and low cost

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