Sonotrode Cooling for High-Speed Ultrasonic Web Bonding

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Solution Overview

Problem

Ultrasonic forming and bonding processes in the absorbent article industry face inefficiencies due to localized overheating and deformation of sonotrodes, leading to tears, rips, and holes in substrates, which limit line speed and throughput.

Innovation Solution

Implementing cooling methods that utilize heat sinks thermally coupled to sonotrodes to dissipate thermal energy, combined with materials having varying thermal conductivities and insulation to prevent overheating, allowing for high line speeds and substrate integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ultrasonic vibration energy is applied to bond substrates, then bonding strength is improved, but localized overheating causes substrate defects

Engineering Contradiction:

Improvebonding strengthVSAvoidlocalized overheating

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

A heat sink is introduced as an intermediary component between the sonotrode and the substrate. The heat sink absorbs excess thermal energy generated during ultrasonic bonding, preventing direct transfer of heat to the substrate that would cause defects. This mediator allows the bonding process to proceed at high energy levels while protecting the substrate from harmful thermal effects.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful thermal energy is extracted from the bonding interface by the heat sink, which acts as a thermal sink. The heat sink removes excess heat that would otherwise be transferred to the substrate, separating the useful bonding function from the harmful thermal side effect.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If sonotrode material has low thermal conductivity, then fatigue resistance is improved, but heat dissipation becomes insufficient

Engineering Contradiction:

Improvefatigue resistanceVSAvoidheat dissipation

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The system is segmented into two functional parts: the sonotrode made of fatigue-resistant material (titanium) and the heat sink made of thermally conductive material. This segmentation allows each component to optimize its specific function - the sonotrode for fatigue resistance and the heat sink for heat dissipation - while working together to solve the overall problem.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system uses a composite structure combining titanium sonotrode (for fatigue resistance) with a heat sink material (for thermal conductivity). This composite approach allows the sonotrode to maintain its fatigue-resistant properties while the heat sink component provides the necessary heat dissipation capability.

Inventive Principle:

Principle #40Composite materials

3Productivity

If line speed is increased to improve productivity, then throughput is improved, but substrate defects increase

Engineering Contradiction:

Improveline speedVSAvoidsubstrate defect rate

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The heat sink is positioned and activated before the substrate enters the bonding zone, pre-establishing a thermal management system that will prevent overheating during high-speed operation. This preliminary preparation allows the system to handle high line speeds without generating substrate defects.

Inventive Principle:

Principle #10Preliminary action

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

Achieves substrate bonding with minimal defects at line speeds up to 700 m/min, ensuring consistent hook and projection formation without tears or holes, even at high coverage rates.

Implementation Method 1

cooling the second device by transferring thermal energy from the second device to a heat sink

Methodology Applied

Scientific EffectThermal energy transfer: Conduction (thermal)

Implementation Method 2

a buffer material intermediate the heat sink and the second device... transferring thermal energy from the second device through the buffer material to the heat sink

Methodology Applied

Scientific EffectVibration isolation: Damping

Implementation Method 3

sources of vibration energy may use ultrasonic energy... transmitting vibrational energy from the second device toward the first device via the nip to alter the substrate

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

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

Methodology Applied

Scientific EffectHysteresis losses: Hysteresis

Data Source

PatentUS12616951B2Cooling methods for ultrasonic forming and bonding of polymeric webs

Publication Date: 2026.05.05 PROCTER & GAMBLE CO

AI summary

Methods and apparatuses for manufacturing portions of absorbent articles may include or facilitate conveying a substrate through a nip formed between a first device and a second device, transmitting vibrational energy from the second device toward the first device via the nip to alter the substrate, and cooling the second device by transferring thermal energy from the second device.