Robotic Ultrasonic Welding vs TIG Welding

There is no shortage of welding applications that can be automated by industrial robots. While it is nice to have a variety of robotic welding methods to select from, finding the right process for your production may seem overwhelming. Below is a comparison of two of those robotic welding methods, ultrasonic and TIG welding.

Tungsten inert gas (TIG) welding is one of the most common welding processes automated by six axis robots. For decades manufacturers have been deploying the FANUC Arcmate 120ic and other TIG welding robots. As manufacturers have begun to diversify their materials, they are automating welding methods outside of the traditional arc welding ones. Ultrasonic welding is one of those methods. Although it has been around for years it is still fairly new to robotic automation.

Ultrasonic welding robots fuse workpieces together through ultrasonic vibrations. They are integrated with an ultrasonic actuator which generates the vibrations through an electrical voltage. The heat emitted from the vibrations melts the workpieces, creating a weld. Articulated robots with medium to heavy payload capacities are best for automating ultrasonic welding. The end-effectors used for this process can weigh 70 pounds or more, so a higher payload robot is required. The ABB 4600-45 is ideal for ultrasonic welding.

TIG welding is part of the group of traditional arc welding applications frequently automated by industrial robots. It involves using a non-consumable tungsten electrode, electric arc, and shielding gas. During welding an arc forms between the electrode and workpieces, melting and joining the workpieces together. Shielding gas is used to protect the weld pool from contaminants, ensuring a high-quality weld. Six-axis robots can also be used for automating TIG welding. Robots used for TIG automation typically feature lighter payloads and slim robotic arms as the EOAT is not has heavy as those used for ultrasonic welding. The Yaskawa Motoman MA1400 is popular for TIG automation.

Ultrasonic welding differs from TIG welding since it does not involve an electrode or shielding gas. Like TIG welding, ultrasonic welding can be used to join a variety of metals together. Unlike TIG, ultrasonic welding can also weld plastic workpieces, giving it a major advantage. As manufacturers have begun to turn to materials other than metals, the ability to automate ultrasonic welding with industrial robots has become extremely beneficial. Ultrasonic welding robots are being used in the automotive and electronic industries due to their plastic welding capabilities, making the assembly of interior vehicle components and battery packs easier.

While TIG welding robots cannot weld plastics, they can weld most metal types including steel, aluminum, and copper. However, they are limited to thin metals. Thick metal workpieces are not recommended for robotic TIG welding.

Another difference between ultrasonic welding robots and TIG welding robots is their speed. Robotic ultrasonic welding is an extremely fast application. Robots can complete welds within 500 milliseconds with the ultrasonic method. Robotic TIG welding is on the opposite side of the speed spectrum. The main focus of robotic TIG welding is precision rather than speed which is why it is the top choice for fine, detailed welds.