Drives and Controls Magazine

Servo drives challenge pneumatic welders

01 February, 2003

Servo actuators challenge pneumatics for welding

Traditional pneumatic actuators for welding machines are starting to be challenged by electrically-powered, servo-driven rivals. One of the first to emerge comes from the US motion control specialist, Tol-O-Matic, but other companies, including Bosch Rexroth, are also known to be developing servo drives for welding applications.

Electrical drives have many potential attractions in these applications, including their compact size, light weight, long lives, low maintenance, and good repeatability and thrust control. They do not need an air supply or cooling, for most applications.

Tol-O-Matic`s HT series actuators (above) are designed to be drive scissor, pinch or C-style welding guns. They combine a motor with actuator and feedback components, and are available with thrusts of up to 1,040kg. They are rated for up to 6 million welds, but in tests have exceeded 12 million operations - much longer than the lives of most pneumatic actuators.

The motion of the welding tip can be programmed to produce consistent, uniform welds and to extend electrode lives.