Sonic welding, aka ultrasonic welding, unites parts subjected to high-frequency sound waves. The waves vibrate the seams of the plastic, causing friction. Friction creates focused heat. Heat melts, or in this case, welds the parts together. This process is very clean because it doesn’t require the introduction of any other foreign material. It can also form a nearly unbreakable bond and hermetic seal.

Sonic welding, therefore, is very similar to vibration welding. A side note here. There are two types of vibration welding: linear and axial. The most common is linear vibration. In this case, friction is created by a linear, back-and-forth, motion. However, axial, or orbital, vibration welding permits irregular-shaped plastic materials to be welded. In general, vibration welding, like sonic welding, is capable of creating strong, pressure-tight joints at a very rapid rate. Sonic welding is ideal for large or small jobs. It’s also reliable and precise in its applications.

In regard to sonic welding, there are many things that are dependent on sonic welding. In your house, for example, items that rely on the sonic process include DVD players, cell phone parts, computer parts and many aspects of your automobile. In the realm of medicine, sonic welding makes small, intricate medical instruments a reality. Often, these surgical tools require durable, sterile plastic materials.

Sonic welding is a technique that has been in use for many decades. One reason is the price. Sonic welding is very reasonable when compared with other forms of welding. It’s also highly dependable in regards to bonding together materials that may be too small to accommodate spin welding or hot plate welding. Sonic waves allow welders to focus and pinpoint the bonding frequency necessary. This is why it’s often used to fashion medical equipment. The work surface area only needs to be several square centimeters. It’s ideal for constructing delicate equipment.

Learn about the inner workings of thermal assembly systems and other plastic welders at Plastic Assembly Systems, the world leader in plastic assembly solutions, by logging onto