Patent ID: 8720516
Filing Date: 2014-05-13
Classification: B29C,B29K

Abstract:
1. An ultrasonic welding system comprising: an ultrasonic welding stack mounted for linear movement and applying a controlled force, speed, or a combination of force and speed to a first workpiece to urge said first workpiece against a second workpiece to which said first workpiece is to be joined; an electrically powered linear actuator comprising a movable element coupled to said ultrasonic welding stack, the electrically powered linear actuator causing, responsive to control inputs, said movable element and said ultrasonic welding stack to move with a controlled force, speed, or force and speed; a controller to provide control inputs to at least one of the electrically powered linear actuator or the servo motor to control an output of the electrically powered linear actuator; and at least one sensor to measure at least one corresponding control variable and to output a signal corresponding to the control variable to the controller, wherein the controller, based on said signal output by said at least one sensor, causes the electrically powered linear actuator movable element to apply through the ultrasonic welding stack a predetermined positive initial force at an initiation of a welding operation and limits a linear displacement of said ultrasonic welding stack to a predetermined initial displacement at the initiation of the welding operation until the signal output from said at least one sensor indicates that a sensed variable satisfies a predetermined condition, and wherein the controller, based on said signal output by said at least one sensor indicating that the predetermined condition has been satisfied, further causes the electrically powered linear actuator to move the ultrasonic welding stack only after the signal output from said at least one sensor indicates that the sensed variable satisfies the predetermined condition and in accord with a default weld profile or a weld profile selected from a plurality of available weld profiles, and wherein, following the initiation of the welding operation, any motion of the ultrasonic welding stack is delayed until the predetermined condition is satisfied.