Infrared Nonwoven Relofting With a Movable Axis
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Solution Overview
Problem
Existing methods for relofting nonwoven substrates in absorbent article manufacturing face challenges such as web compression, increased roll sizes, and inefficiencies with infrared heat sources, particularly during high acceleration and deceleration rates in assembly line operations, leading to unrelofted lengths and potential damage to substrates.
Innovation Solution
A method and apparatus utilizing a movable axis to selectively direct infrared radiation onto the substrate, ensuring it is only heated when the radiation sources are operational and the substrate is at desired speeds, thereby maintaining substrate integrity and minimizing waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If infrared heat sources are used to reloft substrates, then substrate caliper is increased, but substrate damage occurs during high acceleration and deceleration rates
Solution Approach 1:
The patent employs a movable axis that can dynamically adjust the position of infrared radiation sources relative to the substrate. During high acceleration and deceleration rates, the axis moves to position the radiation sources such that they do not directly contact or excessively heat the substrate, preventing damage while still enabling effective relofting during steady-state operation.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor substrate speed, acceleration, and position. Based on this feedback, the control system adjusts the axis position and radiation source activation to prevent substrate damage during transient conditions while maintaining effective relofting during normal operation.
2Manufacturing precision
If infrared heat sources operate continuously, then substrate relofting is effective, but unrelofted lengths increase during start-ups and shut-downs
Solution Approach 1:
The patent uses a movable axis to position infrared radiation sources in advance before the substrate enters the heating zone. During start-ups and shut-downs, the axis pre-positions the sources to optimize heating timing, ensuring the substrate receives appropriate heat treatment only when at desired speeds, thereby minimizing unrelofted lengths.
Solution Approach 2:
The system dynamically adjusts the axis position and radiation source activation based on real-time substrate speed and position. This dynamic control ensures that infrared heating is applied precisely when the substrate is at desired speeds, preventing both over-heating during transients and under-heating that would create unrelofted lengths.
3Quantity of substance
If web materials are wound tightly on rolls, then transportation and storage costs are reduced, but web compression occurs resulting in reduced thickness
Solution Approach 1:
The patent applies infrared radiation to change the thermal parameters of the web material, causing the fibers to expand and increase in thickness (relofting). This parameter change restores the web's original thickness after compression during tight winding, allowing the material to maintain both compact storage and restored thickness properties.
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 effectively relofts substrates with increased caliper, reduces unrelofted lengths, and prevents damage during assembly line start-ups and shut-downs, enhancing manufacturing efficiency and product quality.
Implementation Method 1
irradiating the first surface of the first length of the substrate with infrared radiation from the first infrared radiation source
Implementation Method 2
the application of heat to some types of web materials may increase the thickness or caliper of the web materials, referred to herein as 'relofting'
Data Source
AI summary
Aspects of the present disclosure relate to methods and apparatuses for relofting nonwoven substrates. During the relofting process, a substrate is directed to advance in a first direction such that a length of the substrate is in a facing relationship with a radiation source. The advancing substrate is relofted by irradiating the length of the substrate with infrared radiation from the infrared radiation source. The substrate comprises a first caliper upstream of the radiation source and the substrate comprises a second caliper downstream of the radiation source greater than the first caliper. The substrate may also be redirected around an axis to advance the substrate in a second direction, wherein the second direction is different than the first direction. The axis may be selectively movable between a first position and a second position to selectively subject the substrate to infrared radiation and remove the substrate from the infrared radiation.