Ultrasonic Bonding Sonotrode Cooling for High-Speed Polymeric Webs
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Solution Overview
Problem
Ultrasonic forming and bonding processes face inefficiencies due to localized overheating of sonotrodes, leading to substrate defects such as tears, rips, and holes, which limit line speeds and throughput in industries like absorbent articles.
Innovation Solution
Implement cooling methods by conveying chilled fluids through cavities or using projections on the sonotrode to transfer thermal energy away from the localized overheating regions, maintaining effective cooling even at high line speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic vibration energy is applied to bond or form substrates, then substrate bonding and surface feature creation are achieved, but localized overheating of the sonotrode occurs causing substrate defects
Solution Approach 1:
A fluid coupling medium is introduced between the sonotrode and substrate to act as a thermal intermediary. This fluid absorbs excess heat from the sonotrode working surface while allowing ultrasonic energy transmission, preventing localized overheating and substrate defects. The fluid serves as a heat sink that maintains sonotrode temperature while enabling continuous ultrasonic bonding or forming operations.
2Productivity
If high line speeds are used to improve productivity, then throughput increases, but substrate defects such as tears, rips, and holes occur due to overheating
Solution Approach 1:
The fluid coupling medium enables continuous ultrasonic bonding or forming operations at high line speeds by continuously removing heat from the sonotrode working surface. This maintains stable process conditions without thermal accumulation, allowing sustained high-speed production while preventing substrate defects that would otherwise limit throughput.
3Reliability
If cooling methods are implemented to prevent substrate defects, then substrate quality improves, but process complexity increases
Solution Approach 1:
A hydraulic cooling system using fluid circulation is employed to cool the sonotrode working surface. The fluid is pumped through channels or sprayed onto the sonotrode surface, providing efficient heat removal through convection. This hydraulic approach offers controllable, uniform cooling with relatively simple system architecture compared to other cooling methods, maintaining substrate quality while minimizing added complexity.
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
Enables high line speeds and throughput without substrate defects, achieving coverage up to 99% and speeds of 500-700 m/min, improving substrate quality and process efficiency.
Implementation Method 1
conveying a chilled fluid through the cavity. and cooling the second device by transferring thermal energy from the second device to the chilled fluid
Implementation Method 2
cooling the second device by transferring thermal energy from the second device to the chilled fluid
Implementation Method 3
The source of vibration energy may use ultrasonic energy. The source of vibration energy may press against the substates to melt, to soften, and/or to deform a portion of the substrates
Implementation Method 4
vibration energy may create a polymer flow or deformation into the projection recesses and/or against the nubs by heating a nonwoven and/or film via hysteresis losses from repeated compression and expansion of the polymer material in response to the vibration energy
Data Source
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AI summary
Methods and apparatuses for manufacturing portions of absorbent articles may include or facilitate conveying a substrate 106 through a nip formed between a first device 101,201 and a second device 102, transmitting vibrational energy from the second device toward the first device via the nip to alter the substrate, and cooling the second device by providing a cavity 902, 912 in the second device 102 proximate to a working surface of the second device and conveying a chilled fluid through the cavity 902, 912.