Servo-Driven Ultrasonic Press for Precise Weld Force Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasonic welding systems face challenges in precisely controlling the force and speed during the welding process, leading to inconsistent weld quality and strength, particularly when working with thermoplastic parts.
Innovation Solution
The implementation of an ultrasonic welding apparatus with a linearly movable ultrasonic welding stack coupled to an electrically powered linear actuator, which includes a servo motor and a converter to produce controlled linear motion, along with a motion controller and torque sensor for precise force and speed control, ensures consistent application of force and speed during the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ultrasonic welding systems are used, then the basic welding function is achieved, but precise control of force and speed during the welding process is difficult, leading to inconsistencies in weld strength and quality
Solution Approach 1:
The patent implements feedback control by using a torque sensor to detect the actual torque produced by the servo motor and supplying this signal to the motion controller. The motion controller adjusts the electrical power delivered to the servo motor based on this feedback, creating a closed-loop control system that maintains precise control of force and speed during welding, thereby ensuring consistent weld strength and quality.
Solution Approach 2:
The patent replaces conventional mechanical control systems with an electrically powered linear actuator comprising a servo motor and integrated converter. This substitution enables more precise and programmable control of the welding stack's linear motion, allowing for programmable velocity and force profiles that improve manufacturing precision while maintaining manageable device complexity through electrical control rather than complex mechanical linkages.
2Manufacturing precision
If an electrically powered linear actuator with servo motor is used, then precise control of force and speed is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the servo motor and the converter into a single integrated linear actuator unit. This integration combines the rotational motion generation capability of the servo motor with the linear motion conversion function of the converter, achieving precise force and speed control while reducing the overall device complexity by eliminating the need for separate, independent components and their associated mounting and alignment systems.
3Reliability
If programmable velocity and force profiles are implemented, then weld quality is improved, but the control system complexity increases
Solution Approach 1:
The patent implements dynamic control by enabling programmable velocity and force profiles that can be adjusted during the welding process. The motion controller receives commands to vary the servo motor's electrical power delivery over time, creating dynamically adjustable welding parameters. This allows optimization of weld quality for different workpiece conditions while the integrated feedback system manages the control complexity through automated real-time adjustments based on actual torque measurements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables precise control over the welding process, resulting in consistent and optimal weld strength by allowing for programmable velocity and force profiles, reducing the likelihood of over-advancement and subsequent weak welds, and enhancing the overall efficiency and reliability of the ultrasonic welding system.
Implementation Method 1
an electromechanical transducer for converting electrical energy to mechanical vibrations
Implementation Method 2
The integrated converter may include a lead screw mechanically coupled to the servo motor, and a follower unit mechanically coupled to the lead screw for producing the linear motion in response to rotational motion of the lead screw.
Implementation Method 3
an electromechanical transducer for converting electrical energy to mechanical vibrations, a booster coupled to the transducer for amplifying the mechanical vibrations, and a welding horn coupled to the booster for applying the mechanical vibrations to the first workpiece
Data Source
AI summary
An ultrasonic welding system includes an ultrasonic welding stack mounted for linear movement and for applying a controlled force, speed, or a combination of force and speed to a first workpiece to press the first workpiece against a second workpiece to which the first workpiece is to be joined, and an electrically powered linear actuator coupled to the ultrasonic welding stack for moving the stack while applying a controlled force, speed, or a combination of force and speed to said stack, the actuator including an electrical servo motor producing rotational mechanical motion and an integrated converter for converting the rotational motion into linear motion. In one specific implementation, a controller is coupled to the linear actuator for controlling the force applied by said actuator to the ultrasonic welding stack, and a sensor is coupled to the servo motor for producing a signal related to the torque produced by the servo motor and supplying that signal to the controller. In a second specific implementation, a load cell is used for force feedback to the motion controller with a linear or rotary position feedback device used to provide position and velocity feedback to the motion controller. The controller controls the electrical power delivered to the servo motor so as to control the torque and speed outputs of the motor.