The correct selection of the welding positioner is an important guarantee to prevent the welding penetration and to avoid the phenomenon of incomplete penetration. The incorrect specification will also cause the formation of porosity.

The penetration of 3mm automatic welding is close to the limit of non penetration. When the penetration N1 is less than 1.5mm, the phenomenon of non penetration will occur. When N1 is less than 2.0, it is easy to be penetrated, and the change range of penetration is less than 1mm. Therefore, the welding specification is strictly limited.

For several specifications of φ 1.6 welding wire, the current is represented by: Main weld current I1 = 160A, 180A, 200A; back welding current I2 = 220a, 240A, 260a, 280A. For the first kind of specification, the normal degree of penetration cannot be guaranteed in fact because the main weld does not intersect with the weld penetration of the back cover. The second kind of specification should produce the phenomenon of weld through.

Because zidognh is a small specification, its required stability must be very high, otherwise it will cause the phenomenon of penetration or lack of penetration, the weld forming will also deteriorate, and defects such as porosity may appear. We require the fluctuation range of current to be controlled within ± 10a and the voltage to be controlled within ± 2v-1, so that we can get satisfactory results.

The welding positioner involves the user's concept of equipment, as well as the different uses for manual welding and automatic welding. When selecting and designing the welding positioner, in addition to the main positioner freedom, it should also consider increasing the auxiliary positioner freedom. For example, the welding of large parts can increase the lifting movement freedom, such as the above-mentioned products in the United States and Germany

In addition, for some weldments, due to the simple distribution of welds, the ship welding requirements of most and important welds in weldments can be solved by using one degree of freedom of rotation, while the rest of the non important welds can not be carried out by ship fillet welding, but flat fillet welding can be carried out. In this way, in order to simplify the equipment cost, the welding positioner with single degree of freedom or functional degradation, i.e. single rotary positioner, is considered in the process It is also required to increase the auxiliary degrees of freedom, such as lift type and tailstock mobile type

There are also some station positioners. In order to meet the process requirements of welding station, some degrees of freedom of this welding positioner are not related to welding. In addition, considering the station design and stability, two or more welding positioners are designed in combination, so a variety of station transformation and combined welding positioner products appear.