Ultrasonic Welds: Understanding Failures in Metal and Plastic Joints

Ultrasonic welding (USW) is a high-frequency vibration-based joining process used for both metals and plastics. This technique enables solid-state bonding for metals and molecular fusion for thermoplastics, making it a versatile and efficient manufacturing method. With applications across industries such as automotive, electronics, medical devices, packaging, and aerospace, ultrasonic welding offers advantages such as rapid processing times, low energy consumption, and the ability to join dissimilar materials. Although several design and manufacturing considerations (such as surface preparation, material compatibility, joint design and geometry, and tooling) can be optimized for peak bond quality, the causes of failure-inducing imperfections are often less understood by the general engineering community. This talk is a discussion of common factors to consider when conducting a failure analysis of ultrasonically welded components.