Tapeless Thermal Splicing for Continuous Absorbent Web Lines
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Solution Overview
Problem
Conventional splice boxes require tape for forming splices between rolls, have limited strength, and are not compatible with robotic automation, leading to inefficiencies and manual labor requirements in absorbent article manufacturing.
Innovation Solution
A method and system for forming a tapeless splice bond between expiring and new rolls using a thermal bonding apparatus with a knife cutting system and ultrasonic system, allowing for robotic automation and continuous operation of the manufacturing line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional splice boxes use tape to form splices between rolls, then the splicing process can be performed, but the splice strength is limited and manual labor is required
Solution Approach 1:
The patent replaces the mechanical tape-based splicing system with an ultrasonic welding system that uses high-frequency vibration to melt and bond web materials. The ultrasonic horn applies vibrational energy to the interface between expiring and new rolls, creating a fusion bond without requiring manual tape application. This substitution eliminates manual labor while significantly increasing splice strength through thermal-mechanical bonding.
Solution Approach 2:
The ultrasonic welding process utilizes phase transitions of the web material. The high-frequency ultrasonic vibrations generate localized heat at the interface between materials, causing the thermoplastic components of the web to melt and fuse. As the materials cool, they solidify into a strong bonded joint. This phase transition approach creates bonds stronger than mechanical tape attachment.
2Productivity
If conventional splice boxes require offline preparation and manual steps, then splicing can be performed, but the overall process efficiency is reduced
Solution Approach 1:
The system performs preliminary actions by automatically detecting when the expiring roll is nearing depletion and initiating the splicing sequence without manual intervention. Sensors monitor roll diameter or web tension to trigger the splicing process in advance, allowing the new roll to be positioned and the ultrasonic bonding to commence automatically. This eliminates downtime by preparing and executing the splice before the manufacturing line must stop.
Solution Approach 2:
The splicing system is designed to be self-servicing through automated web guidance, alignment, and bonding. The ultrasonic welding apparatus automatically positions the horn, applies the correct vibration parameters, and completes the bond without operator involvement. The system self-regulates the splicing process based on sensor feedback, eliminating the need for manual preparation steps and maintaining continuous production.
3Strength
If conventional splice boxes form butt splices, then the splicing process is simple, but the splice strength is limited
Solution Approach 1:
Instead of forming a simple butt splice where ends meet in one dimension, the ultrasonic welding system creates an overlapping lap joint that extends the bond interface in the transverse direction. The expiring and new rolls overlap by a controlled distance, providing a larger bonding surface area. The ultrasonic horn welds through this overlap zone, creating a distributed bond that is significantly stronger than a point-contact butt splice, justifying the added geometric complexity.
4Extent of automation
If conventional splice boxes are not compatible with robotic automation, then manual operation is possible, but automation efficiency cannot be achieved
Solution Approach 1:
The patent replaces manual mechanical operations with an automated ultrasonic welding system that interfaces with robotic automation. The ultrasonic horn is mounted on a programmable positioning system that can be controlled by robots or PLCs. Sensors provide feedback for automated web tracking and alignment, enabling the entire splicing sequence to be executed by automation systems while maintaining ease of operation through programmable control and simple material loading.
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 system forms a stronger splice bond without interruptions, reduces material waste, and enhances compatibility with robotic automation, ensuring continuous operation of the absorbent article manufacturing line.
Implementation Method 1
an ultrasonic system comprised of a Sonotrode (horn) and an anvil
Implementation Method 2
the thermal bonding apparatus bonds across the full width of the overlapped web
Implementation Method 3
a knife cutting system
Implementation Method 4
Using a vacuum to hold a second portion of the second roll of the material proximate to a leading edge
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A method is presented for providing a continuous web (120, 130) to an absorbent article manufacturing line (149). The method includes conveying a first roll of material through a splice box (102). The method also includes providing a second roll of the material extending into the splice box. The method also includes sensing upcoming expiration of the first roll of material. The method also includes using a first and second vacuum to hold a respective first portion (133) of the first roll and a second portion (143) of the second roll against first and second components of a thermal welding apparatus. The method also includes forming a thermal weld at the splice location between the first and second portions (133, 143). The method also includes cutting the first roll of material upstream of the thermal weld. The method also includes conveying the second roll of material through the splice box (102) without stoppage of the absorbent article manufacturing line (149).