Ultrasonic Weld Head Z-Axis Control for Precise Bond Force

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Solution Overview

Problem

Existing ultrasonic welding technologies face limitations in cost, operational efficiency, flexibility, and portability, failing to meet market demands for efficient volume production of interconnections between materials.

Innovation Solution

The ultrasonic welding system incorporates a z-axis motion system with a z-axis forcer and overtravel mechanism, allowing precise control of bond forces through a combination of linear motor-driven and pneumatic systems, enabling efficient welding of conductive terminals to workpieces with adjustable force calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If existing ultrasonic welding technology is used, then welding capability is provided, but cost, operational efficiency, flexibility, and portability fail to meet market demands

Engineering Contradiction:
Improveoperational efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The welding system is divided into modular components: a weld head assembly containing the ultrasonic converter and sonotrode, a z-axis motion system with forcer and overtravel mechanism, and a support structure. This segmentation allows each module to be optimized independently while maintaining overall system efficiency and reducing complexity through standardized interfaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The weld head assembly is designed as a universal component that can be applied to various welding applications by changing the sonotrode geometry and welding parameters. The z-axis motion system with overtravel mechanism provides a standardized interface for different workpiece types, enhancing flexibility and adaptability across multiple manufacturing scenarios.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If high bond forces are applied for efficient welding, then welding speed and quality improve, but control precision and system flexibility may be compromised

Engineering Contradiction:
Improvewelding speedVSAvoidbond force control precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The z-axis motion system employs dynamic control through a programmable forcer that can adjust bonding force in real-time during the welding cycle. The system transitions from static force application to dynamic force modulation, allowing high bonding forces during the welding phase while maintaining precise control through feedback mechanisms and programmable sequences.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system incorporates feedback mechanisms that monitor welding parameters including bonding force, ultrasonic power, and weld head position. This feedback enables real-time adjustments to maintain precise control over bond forces even at high welding speeds, ensuring consistent weld quality through closed-loop control.

Inventive Principle:
Principle #23Feedback

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 configuration achieves high bond forces with precise control, enhancing operational efficiency and flexibility, suitable for volume production and various applications, including power modules.

Implementation Method 1

Ultrasonic welding may use an ultrasonic converter (e.g., carrying a sonotrode) for converting electrical energy into mechanical movement/scrub (e.g., linear movement/scrub, torsional movement/scrub, etc.)

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

The z-axis motion system includes (i) a z-axis forcer for moving the weld head assembly along a z-axis of the ultrasonic welding system

Methodology Applied
Scientific EffectLinear motor: Linear Motor

Implementation Method 3

allowing precise control of bond forces through a combination of linear motor-driven and pneumatic systems

Methodology Applied
Scientific EffectPneumatic:

Data Source

PatentEP3887085B1Ultrasonic welding systems and methods of using the same
Publication Date: 2024.03.13 KULICKE & SOFFA IND INC
  • EP3887085B1 patent drawingFigure 1A
  • EP3887085B1 patent drawingFigure 1B
  • EP3887085B1 patent drawingFigure 2A

AI summary

An ultrasonic welding system is provided. The ultrasonic welding system includes a support structure for supporting a workpiece. The ultrasonic welding system also includes a weld head assembly including an ultrasonic converter carrying a sonotrode. The ultrasonic welding system also includes a z-axis motion system carrying the weld head assembly. The z-axis motion system includes (i) a z-axis forcer for moving the weld head assembly along a z-axis of the ultrasonic welding system, and (ii) a z-axis overtravel mechanism disposed between the z-axis forcer and the weld head assembly.