Rotary Drum Suction Web Alignment for Absorbent Articles
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Solution Overview
Problem
Conventional manufacturing methods for absorbent articles face issues with positioning accuracy and wrinkle/twist occurrence due to uneven contraction of elastic members, leading to potential shifts and misalignment of workpieces during the assembly process.
Innovation Solution
The apparatus employs a rotary drum with a suction unit that changes the workpiece disposition direction and a web position guiding mechanism to ensure precise alignment, where the central portion of the workpiece contacts the web first, followed by the outer edge, preventing wrinkles and twists by maintaining uniform tension across the elastic member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the suction face is formed with the outer edge portion inclined to the rotary shaft side to restrain difference in circumferential speed, then the workpiece can be conveyed stably, but a gap is produced between the outer edge portion of the workpiece and the web at delivery
Solution Approach 1:
The web guiding mechanism is divided into multiple guiding units positioned at different locations (upstream and downstream of the rotary drum). Each guiding unit independently adjusts web position at its location, allowing differential guidance to compensate for the gap issue while maintaining overall alignment.
Solution Approach 2:
Different guiding strategies are applied at different locations along the web path. The upstream guiding unit positions the web to abut the outer edge portion, while the downstream guiding unit positions the web to abut the central portion, creating local variations in web position to compensate for the suction face inclination effects.
2Ease of operation
If positioning is performed at the outer edge portion of the workpiece to the exclusion of the central portion, then the workpiece position can be adjusted, but the entire workpiece position may shift and wrinkles or twists may occur in the web
Solution Approach 1:
The positioning control is segmented into multiple control points (upstream and downstream guiding units) that independently adjust web position. This allows the system to position the workpiece at the outer edge while maintaining central alignment through the downstream guiding unit, preventing overall position shift and web deformation.
Solution Approach 2:
The web guiding mechanism operates with feedback control to monitor web position and workpiece alignment. Based on this feedback, the guiding units adjust web position dynamically to maintain proper alignment throughout the conveyance process, preventing wrinkles and twists.
3Productivity
If a continuous web is conveyed with elastic members disposed in expanded state, then the absorbent article can be manufactured efficiently, but the elastic member contracts unevenly causing web position shift and workpiece mounting position shift
Solution Approach 1:
The web guiding mechanism is segmented into multiple guiding units positioned at different locations along the web path. Each guiding unit independently compensates for local web position shifts caused by uneven elastic member contraction, maintaining overall web position accuracy despite continuous manufacturing.
Solution Approach 2:
The web guiding units perform preliminary positioning adjustments upstream of the workpiece mounting location to compensate for expected web position shifts. This anticipatory guidance ensures that when the workpiece is mounted, the web is already positioned correctly, preventing mounting position shifts.
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 solution ensures accurate positioning and uniform tension, preventing shifts and misalignment, thereby enhancing the manufacturing process by reducing wrinkles and twists in absorbent articles.
Implementation Method 1
a rotary drum at which there is provided a suction unit for sucking a workpiece
Data Source
AI summary
An apparatus includes a rotary drum for disposing a workpiece on a web and a web position guiding mechanism for guiding a position of the web. The rotary drum includes a suction unit for sucking the workpiece. The suction unit is configured to change a disposition direction of the workpiece from a first disposition direction at the reception point to a second disposition direction at a delivery point. An external shape of the workpiece sucked by the suction unit is an external shape in which an outer edge portion of the workpiece is close to a rotary shaft side of the rotary drum. At an abutment point, a central portion of the workpiece and the web come into contact with each other. At the delivery point, the web is disposed so that an outer edge portion of the workpiece and the web come into contact with each other.