The Benefits of Servo Controlled Spot Welding Robots

Spot welding is an age-old welding application that produces strong joins by strategically welding certain spots on the workpiece. Traditionally performed by skilled workers, it can also be an incredibly dangerous task involving hot sparks, electric currents, and heavy, unwieldly welding guns. It requires plenty of practice and a high level of knowledge to perform effectively, but the high repeatability of the job also makes it a perfect candidate for robotic automation.

Whether in the hands of a skilled welder or a robotic system, the spot-welding gun is tipped with an electrode that both exerts pressure on the piece to keep it in place, and also conducts the current that heats and fuses the piece. It is preferred over other welding processes by many manufacturers for its reliability and the way it is able to reduce cycle time and reduce costs simultaneously.

And though traditionally these robots would need to be manually positioned and pneumatically powered, demand for servo-controlled spot-welding robots is increasing globally due to the added speed and efficiency they are capable of delivering.

The Problem with Pneumatic Power

Pneumatic powered spot welders have some disadvantages when it comes to the quality and consistency of the welds produced. A pneumatic cylinder which provides the pressing force between the pieces to be welded, by nature, has an inconsistent clamping force from one weld to the next. And since pressure, and not only heat, is essential to form the welds, a low weld force can cause problems or even a product failure down the line. Simply increasing the pressure in the cylinder seems like an easy fix, but can cause a host of other problems, such as rapid wear of the weld cap, burn-through, and increase splattering and contaminants. 

What is a servo?

Short for servomechanism, a servo is an electromagnetic motor that converts electrical energy into precisely controllable movement. Incorporating this technology with multi-geared electronic motors gives manufacturing robots a wider and more sensitive range of motion and – in the case of spot welding – gun control. With such coordinated motion of the welding guns, speed, accuracy, and product quality are all improved, enabling a greater range of material handling applications in multiple robots, not just those performing the welding itself. Servo motors are small, powerful, and easily programmable. In welding robots, they are placed into every joint of the robotic arm, adding dexterity, and improving repeatability and motion control.

The Bottom Line

Servomechanisms have given rise to new applications in robotics and promise even more exciting breakthroughs in the world of manufacturing. Smaller versions are already able to mimic the minute flexibility of hands and fingers when applied to prosthetic medicine, providing enhanced strength, movement flexibility and control, as well as easy programmability. In a future where the dangerous, strenuous, and repetitive tasks of the factory floor are taken out of human hands, servomechanisms are bringing us closer than ever before.

As a global leader in robotics, YASKAWA has decades of expertise in the development of spot-welding robots with a wide range of payloads, reaches, servo-controlled spot-welding guns and integrated spot harnesses, helping our clients to realise the real value of robotic automation and improving their processes to new levels of excellence.