Diaper Core Positioning Under Tension
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Solution Overview
Problem
Conventional methods for producing disposable diapers result in displacement of the absorbent core from its intended position between leg elastic members when the production line is temporarily stopped, leading to off-specification diapers due to asymmetric positioning of the absorbent core and leg elastic members.
Innovation Solution
A method involving continuous feeding and bonding of elastic members to sheet members under tension, with absorbent panels symmetrically positioned between leg elastic members, ensuring the absorbent core remains centered between leg elastic members even during temporary production line stops, by maintaining constant sheet member dimensions and adjusting tensile stress to facilitate proper alignment and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If elastic members are bonded under tension to continuously fed sheet members, then manufacturing efficiency is improved, but sheet displacement occurs when production is temporarily stopped
Solution Approach 1:
The patent applies preliminary anti-action by pre-positioning the absorbent core symmetrically between the leg elastic members before bonding. This preliminary positioning creates a reference framework that prevents displacement during production stops, as the symmetric arrangement ensures that any tension-induced movement affects both sides equally, maintaining the core's centered position.
Solution Approach 2:
The patent implements preliminary action by continuously feeding and positioning the sheet members and elastic members before the actual diaper assembly process. The continuous feeding mechanism maintains constant tension and positioning, ensuring that when production stops and resumes, the materials are already in the correct positions without requiring manual readjustment.
2Manufacturing precision
If manual readjustment is performed to maintain absorbent core positioning, then positioning accuracy is improved, but production time is increased
Solution Approach 1:
The patent applies self-service by designing the bonding system to automatically maintain positioning accuracy without manual intervention. The continuous feeding mechanism and symmetric positioning arrangement enable the system to self-correct and maintain precision during temporary stops, eliminating the need for manual readjustment operations.
Solution Approach 2:
The patent implements continuity of useful action by maintaining continuous feeding and bonding of sheet members and elastic members throughout the production process. This continuous action ensures that positioning accuracy is maintained without interruption, allowing production to resume immediately after temporary stops without time-consuming manual readjustment.
3Productivity
If absorbent core is positioned asymmetrically, then production speed is maintained, but product quality deteriorates
Solution Approach 1:
The patent applies asymmetry in a controlled manner by intentionally creating a symmetric reference framework through the positioning of leg elastic members and absorbent core. This deliberate symmetric arrangement serves as a reference that maintains positioning accuracy even when production conditions vary, allowing high-speed production without compromising product quality.
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
This method ensures the absorbent core remains symmetrically positioned between leg elastic members, preventing displacement and ensuring the production of specification-compliant diapers by maintaining constant sheet member dimensions and adjusting tensile stress for proper alignment and bonding.
Implementation Method 1
continuously feeding elastic members for a front sheet member and elastic members for a rear sheet member in parallel to each other under tension in a first machine direction and bonding these elastic members to webs of the front and rear sheet members, respectively
Implementation Method 2
bonding the elastic members for the crotch region under tension to at least one of the liquid-pervious sheet and the liquid-impervious sheet
Data Source
AI summary
The present invention aims to provide a method for making disposable diapers so improved that no displacement of the absorbent core from the middle between a pair of the leg elastic members. The method comprises the step P1 of bonding under tension elastic members to webs continuously fed in a machine direction MD to form front and rear sheet members the step P2 of bonding an absorbent panel provided along opposite long sides of a rectangle with a pair of elastic members for a crotch region and including an absorbent core bonded thereto so as to be symmetric about an imaginary center line bisecting a distance between a pair of the elastic members for the crotch region to the front and rear sheet members at regular intervals and the step P3 of cutting the front and rear sheet members.