Rotary Sonotrode Connection Point Shift for Ultrasonic Sealing
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Solution Overview
Problem
Prior art sonotrodes used in ultrasonic package sealing systems have a relatively short lifespan due to high stress and heat generation at the interface between the sonotrode and input tools, leading to frequent replacements and increased production costs.
Innovation Solution
The sonotrode connection point is repositioned from the nodal region to a region with minimal transverse displacement, approximately ⅛λ away from the node of the sonotrode and input tool, reducing relative shear motion and heat generation, and utilizing a 3λ/2 wavelength input tool configuration to minimize stress and maintain resonant frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sonotrode connection point is located at the nodal region, then the ultrasonic waves are effectively received and propagated, but high stress and heat generation occur at the interface with input tools, resulting in short lifespan
Solution Approach 1:
The patent changes the connection location parameter from the nodal region to a position 1/8 wavelength away from the node. This parameter change reduces relative shear motion between the sonotrode and input tool interfaces, thereby reducing heat generation and extending sonotrode lifespan from approximately 4 hours to at least 152 hours of continuous operation.
2Reliability
If the sonotrode connection point is located at the nodal region, then the ultrasonic waves are effectively received and propagated, but frequent replacement is required, increasing production time and costs
Solution Approach 1:
The patent changes the connection location parameter from the nodal region to a position 1/8 wavelength away from the node. This parameter change reduces relative shear motion between the sonotrode and input tool interfaces, thereby reducing heat generation and extending sonotrode lifespan from approximately 4 hours to at least 152 hours of continuous operation.
3Ease of manufacture
If the input tool uses a 1/2 wavelength configuration, then the connection is straightforward, but high stress occurs at the interface leading to failure
Solution Approach 1:
The patent changes the input tool wavelength configuration from 1/2 wavelength to 3/4 wavelength. This parameter change positions the input tool node 1/8 wavelength away from the sonotrode node, reducing relative shear motion and stress at the interface, thereby preventing failure while maintaining manufacturability.
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
The modified sonotrode design significantly extends lifespan from 4 hours to at least 152 hours and stabilizes heat generation, reducing the likelihood of failure and improving operational efficiency.
Implementation Method 1
a body with nodal and anti-nodal regions that is configured to propagate ultrasonic waves received at a nodal region along a first direction
Implementation Method 2
the body is further configured to stretch and compress along the second direction based on corresponding peaks and valleys of the waves propagating along the second direction
Implementation Method 3
reducing relative shear motion and heat generation
Data Source
AI summary
An ultrasonic welding system that includes a rotary sonotrode, having a body that includes a first horizontal side having a first antinode; a second horizontal side having a second antinode; a first vertical side having a first node; a second vertical side having a second node; and a middle region, an upper region, and a lower region, wherein the length of the middle region is greater than the length of the upper region and greater than the length of the lower region; at least one ultrasonic transducer that is transversely aligned with the rotary sonotrode; and at least one input tool disposed between the rotary sonotrode and the transducer that includes a node and is an integral part of the transducer or is a component separate from the transducer, wherein the input tool is connected to the rotary sonotrode at the middle region thereof on either the first vertical side or the second vertical side, and wherein the connection point between the input tool and the sonotrode is located a predetermined distance away from the node of the sonotrode and a predetermined distance away from the node of the input tool.