According to the practical experience, this paper introduces several kinds of commonly used welding positioners and their selection principles.

1. Types of commonly used welding positioner

The basic forms of the commonly used manual welding positioner are the extended arm type, the tilting and turning type and the double column single turning type.

(1) double column single rotary type

The main feature of the welding positioner is that the motor-driven working device at one end of the column is running in a rotation direction, and the other end is driven by the driving end. The columns on both sides can be designed as lifting type to meet the welding requirements of structural parts of different specifications. The disadvantage of this type of welding positioner is that it can only rotate in a circular direction, so it is necessary to pay attention to the suitability of the weld form when selecting it.

(2) double seat head tail double rotary

The double seat head tail double rotation welding positioner is the movable space of the welded components. On the basis of the double column single rotation welding positioner, another rotation degree of freedom is added. This kind of welding positioner is more advanced and has a large welding space. It can rotate the workpiece to the required position. At present, it has been successfully applied in many engineering machinery manufacturers.

(3) L-shaped double rotary

The working device of this kind of welding positioner is L-shaped, which has two rotational degrees of freedom, and can rotate in any direction of ± 360 °. The welding positioner has the advantages of good openness and easy operation.

(4) C-shaped double rotary

The C-shaped double rotation welding positioner is the same as the L-shaped double rotation welding positioner, but the fixture of the welding positioner is slightly changed according to the shape of the structure. This kind of welding positioner is suitable for the welding of loader, excavator bucket and other structural parts.

2. Selection principle of positioner

The selection principles of welding positioner are as follows: first, the applicable principle of workpiece; second, the principle of convenient welding; third, the principle of easy operation.

(1) applicable principle of workpiece

The shape of different structural parts of construction machinery is very different, and there are different requirements of displacement during welding. Therefore, the suitable welding positioner should be selected according to the structural characteristics and welding requirements of welding structural parts.

(2) principle of convenient welding

According to the condition of manual welding operation, the selected welding positioner shall be able to transfer any welding seam of the welded part to the position of flat welding or ship welding, so as to avoid vertical welding and overhead welding and ensure the welding quality.

(3) principle of easy operation

Safe and reliable welding positioner with good openness, low operation height and compact structure shall be selected to facilitate workers' operation and placement of welding positioner. If the height of welding operation of the positioner for welded structural parts is high, workers can conduct welding by means of pad height, or adjust the height position by assembling a hydraulic lifting platform.