RF Welding vs. Ultrasonic Welding

Two commonly utilized methods of plastic welding are RF welding and ultrasonic welding. While both processes utilize heat and pressure to create a strong bond, they achieve them in slightly different ways. These differences can make them suitable for distinct applications. That’s why it is important to understand them before you choose a plastic welding solution for your project.

Below, we provide an overview of RF welding and ultrasonic welding. It discusses what they are and highlights the key differences between them to help readers identify which process is right for their needs.

What Is RF Welding?

RF welding—i.e., radio frequency welding—uses high-frequency electromagnetic energy—i.e., radio waves—to create a bond between plastic components. The energy causes the molecules within the materials to vibrate at faster speeds, which generates heat. The heat melts the materials, enabling them to be fused when pressed together and allowed to cool.

What Is Ultrasonic Welding?

Ultrasonic welding uses high-frequency ultrasonic acoustic vibrations—i.e., mechanical vibrations that are above the audible range—to create a bond between plastic components. The vibrations are produced by a welding sonotrode and applied at the joint line of pieces held together under pressure. This process generates friction and, consequently, heat, which melts the materials, enabling them to fuse together as they cool.