Advanced Melt Flow Controls Of Servo Ultrasonic Welding For Medical Devices

Ultrasonic welding of thermoplastics has been widely used by the medical industry to assemble plastic parts and components in just seconds without additional consumables. Development of servo-driven ultrasonic welders introduces unique levels of control to the process. Historically, pneumatic ultrasonic welding systems controlled ultrasonic horn movement indirectly by relieving pressure from air cylinder, which lacks precision, provides less consistent weld results, and compromises weld strength. Today’s servo-driven ultrasonic welding systems control the process through a closed-loop servo position control that dynamically seeks to meet the desired position. The ability of servo systems to program independent speeds for up to 10 different segments of the weld, along with the ability to dynamically sense when melt is being initiated at the beginning of the weld process, yields consistent and stronger weld results with less residual stress.