Ultrasonic Sonotrode Head Layout for Uniform Long Sealing Bands
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasonic sealing devices for packaging materials, such as sonotrodes, face issues with non-uniform vibration leading to uneven sealing bands, parasitic frequencies causing fatigue, and power losses due to water stagnation, which affect the quality and duration of the sealing process.
Innovation Solution
A sonotrode design featuring a single-piece head with three drive units, a nodal plane defined by a continuous edge, and slots that do not cross this plane, reducing parasitic frequencies and water stagnation, while maintaining uniform vibration for long sealing bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If multiple sonotrodes are interconnected to seal longer transversal sealing bands, then the sealing length is increased, but the vibration uniformity deteriorates due to interconnection errors
Solution Approach 1:
The patent merges multiple drive units (first, second, and third drive units) into a single integrated sonotrode structure with a common head, rather than connecting separate sonotrodes. This unified design eliminates interconnection errors and ensures uniform vibration across the entire sealing surface, allowing the sonotrode to seal long transversal sealing bands while maintaining vibration consistency.
2Strength
If slots are added to the sonotrode head for structural purposes, then the structural integrity is improved, but parasitic frequencies are generated causing fatigue
Solution Approach 1:
The patent applies local quality by making the nodal line continuous at specific critical locations (where slots would otherwise cross) while allowing slots to exist in non-critical areas. The continuous nodal line portion prevents parasitic frequencies at the most sensitive locations, while the structure maintains overall integrity through the selective placement of discontinuities only where they do not intersect the nodal line.
3Productivity
If the sonotrode operates for extended sealing time, then productivity is improved, but water stagnation causes power losses
Solution Approach 1:
The patent extracts or removes water from the sonotrode head by incorporating drainage channels that lead to openings in the nodal line. These openings allow water to escape from the head during operation, preventing water stagnation and the associated power losses that would limit extended sealing operations.
4Manufacturing precision
If a continuous nodal line is created across the entire head, then vibration uniformity is improved, but water drainage is blocked
Solution Approach 1:
The patent applies local quality by making the nodal line continuous at specific critical locations (where slots would otherwise cross) while allowing slots to exist in non-critical areas. The continuous nodal line portion prevents parasitic frequencies at the most sensitive locations, while the structure maintains overall integrity through the selective placement of discontinuities only where they do not intersect the nodal line.
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 solution results in uniform and continuous transversal sealing bands, reduced power losses, and extended sealing time, minimizing the risk of incomplete sealing and extending the sonotrode's fatigue life.
Implementation Method 1
each comprising a plurality of stacked piezo-electric elements; and a casing which houses the head
Implementation Method 2
which cooperate with each other to heat the packaging material by means of ultrasonic vibrations
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
A sonotrode (1) comprising: a head (15) which defines a sealing surface (14) elongated along a first direction (A); and a first and a second drive unit (12) distinct from one another, each comprising at least one piezo - electric element (13); wherein first and a second drive unit (12) may be electrically fed by an unique generator so as to cause the oscillation of head (15); the height (H) of head (15) measured along a second direction (B) transversal to sealing surface (14) being substantially equal to the half of the wavelength of the wave oscillating in the direction of second direction (B); sonotrode (1) further comprises: at least one slot (23) which extends through head (15) transversally to first and second direction (A, B); at least a finite number of nodal points (20) at which the amplitude of the oscillation of head (15) is substantially equal to zero; and a plane (P) on which at least some of nodal points (20) lie and which divides head (15) in a first portion (21) and in a second portion (22); the slot (23) being at a certain distance by plane (P).