Force Sensor Positioning in Ultrasonic Welding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasonic processing devices face challenges in accurately measuring welding forces due to high hysteresis from frictional forces and inability to detect transverse forces, limiting their effectiveness in applications with narrow process bandwidths.
Innovation Solution
The force sensor is positioned between the sonotrode and the slide, allowing direct measurement of force changes, with two force sensors measuring forces parallel and perpendicular to the direction of force, and using a piezoelectric sensor to reduce system elasticity and improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the force sensor is arranged within the toggle lever system, then the device can measure force, but the measurement has large hysteresis due to frictional forces between the carriage and carriage guide and within the toggle system
Solution Approach 1:
The force sensor is extracted from the toggle lever system and repositioned between the sonotrode and the slide, removing it from the source of frictional hysteresis while maintaining its force measurement function
Solution Approach 2:
The force sensor acts as an intermediary element between the sonotrode and the slide, directly measuring the welding force without being subjected to the frictional forces present in the toggle mechanism and carriage guide
2Device complexity
If a single force sensor is used in the toggle lever system, then the device structure is simple, but transverse forces perpendicular to the direction of force cannot be measured
Solution Approach 1:
The force measurement function is segmented into two independent sensors: one for measuring force parallel to the direction of force and another for measuring transverse forces perpendicular to the direction of force
Solution Approach 2:
The force measurement capability is extended from one dimension (parallel force only) to two dimensions by adding a second sensor that measures forces in the perpendicular direction
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 enables precise measurement of welding forces, reducing mobility between components and enhancing the ability to process materials within extremely narrow bandwidths, ensuring accurate and stable ultrasonic processing.
Implementation Method 1
using a piezoelectric sensor to reduce system elasticity and improve measurement accuracy
Implementation Method 2
The converter converts an electrical alternating voltage into a mechanical vibration
Implementation Method 3
the ultrasonic oscillating unit has a resonance frequency, the so-called natural frequency, at the desired ultrasonic frequency
Data Source
Figure 1~2
Figure 3~3b
Figure 4
AI summary
The present invention concerns an apparatus for ultrasonic processing of a material web having an ultrasonic vibration unit which has a sonotrode and a converter connected thereto optionally by way of an amplitude transformer, and a counterpart tool, wherein for processing of the material web the web is moved through a gap between the sonotrode and the counterpart tool, wherein the ultrasonic vibration unit is fixed to a carriage moveable relative to the counterpart tool so that the ultrasonic vibration unit can be moved together with the carriage in the force direction, that is to say in the direction of or away from the counterpart tool, wherein there is provided a force sensor for measuring the force applied to the sonotrode by the material web. To provide a corresponding apparatus of the kind set forth in the opening part of this specification, which permits more accurate measurement of the welding force, in order to be able to continuously process by means of ultrasound even situations of use with an extremely small process bandwidth, it is proposed according to the invention that the sonotrode and the carriage are connected together by way of a sensor component which has the force sensor.