Spot welding does not require very high welding robots. Because spot welding only needs point position control, there is no strict requirement for the trajectory of the welding clamp between points, which is why the robot can only be used for spot welding at the earliest.
Welding robots must not only have sufficient load capacity, but also must be fast when shifting from point to point, movement must be stable, and positioning must be accurate to reduce the shifting time and improve work efficiency.
How much load capacity the spot welding robot needs depends on the type of welding gun used. For welding guns that are separated from the transformer, a robot with a load of 30 to 45 kg is sufficient. However, this kind of welding tongs on the one hand, due to the long secondary cable, has a large power loss, and it is also not conducive to the robot to extend the welding tongs into the workpiece for welding; on the other hand, the cable keeps swinging with the robot movement, and the cable is damaged quickly.
Therefore, the use of one-piece welding guns is gradually increasing. The weight of this welding tongs together with the transformer is about 70kg. Considering that the robot must have sufficient load capacity and be able to send the welding tongs to the space position for welding at a relatively large acceleration, a heavy-duty robot with a load of 100 to 150 kg is generally used. In order to meet the requirement of short distance and rapid displacement of the welding gun during continuous spot welding. The new heavy-duty robot has the function of completing a 50mm displacement in 0.3s. This puts forward higher requirements on the performance of the motor, the calculation speed of the microcomputer and the algorithm.