As plastic medical devices get smaller and more intricate, engineers have fewer options for assembling them.
Friction-based joining processes, such as ultrasonic welding, spin welding and vibration welding, work fine for most assemblies, but they can also generate particulates, and that’s a no-no for some medical devices. For example, the fluid channels inside a blood test cassette might be a millimeter wide. Even small particulates could impair the cassette’s performance.