Cellulose Fiber Forming for Parallel-Wall 3D Structures
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Solution Overview
Problem
Existing techniques for forming cellulose fiber structures struggle to efficiently create 3D features with facing parallel walls or surfaces, such as cylindrical protrusions, due to geometric limitations and shearing friction, which leads to defects and increased complexity.
Innovation Solution
A method using a first forming tool with a porous surface and controlled fluid passage ports, combined with negative or positive pressure, allows for the formation of cellulose fiber structures with near-parallel or parallel surfaces by angling the forming surfaces at small angles, reducing shearing friction and enabling efficient compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If single first and second forming tools with parallel forming surfaces are used to form 3D features with facing parallel walls, then the structure can be formed in a single step, but shearing and friction between the forming surfaces and pulp agglomeration cause defects in the desired pulp formation
Solution Approach 1:
The forming process is divided into multiple sequential steps using multiple pairs of forming tools. Instead of attempting to form all parallel-walled features in a single step, the patent segments the formation into successive operations, allowing each step to work on a subset of features with optimized tool angles, thereby avoiding shearing defects while maintaining overall productivity.
Solution Approach 2:
The patent employs dynamic adjustment of forming tool angles during the formation process. By varying the angle between forming surfaces and the direction of compression in different steps, the process adapts to the specific geometric requirements of different 3D features, reducing shearing friction and improving pulp formation quality for parallel-walled structures.
2Adaptability or versatility
If multiple second tools and associated mechanisms are configured to effect compression of the pulp agglomeration against the first tool along varying directions, then facing parallel walls can be formed, but substantial complexity and cost are introduced to the equipment and process
Solution Approach 1:
The patent employs universal forming tools that can be repositioned and reconfigured to perform multiple functions. Instead of requiring dedicated tools for each specific parallel-walled feature, the same forming tools are used repeatedly in different orientations and positions throughout the sequential formation steps, reducing equipment complexity while maintaining the capability to form various parallel-walled structures.
Solution Approach 2:
The patent prepares the pulp agglomeration in advance by forming it against the first tool with a specific initial shape and density before subsequent compression steps. This preliminary action creates a pre-conditioned substrate that is more readily compressible in later steps, reducing the complexity of the compression mechanisms needed while achieving the desired parallel-walled features.
3Manufacturing precision
If forming surfaces are angled at less than about 7 degrees with respect to the forming direction, then shearing friction is reduced, but the ability to form facing parallel walls is compromised
Solution Approach 1:
The patent employs periodic cycles of compression at optimized angles followed by repositioning and re-compression. In each cycle, the forming surfaces are angled at the optimal less than 7-degree angle to minimize shearing friction and defects. Between cycles, the tools are repositioned to accommodate different parallel-walled features, thereby achieving both low shearing friction and accurate parallel wall formation through repeated periodic 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
This approach enables the formation of cellulose fiber structures with complex 3D features like cylindrical tampon applicators, overcoming geometric limitations and reducing defects, while maintaining structural integrity and efficiency.
Implementation Method 1
Pores or ports opening at the first forming surface are of a size that is suitably small enough to prevent passage of any substantial quantity of the fibers through the first tool, such that carrier fluid is drawn or pumped through the first tool and a majority of the fibers in the slurry are not. In effect, the first tool filters the fibers from the slurry
Implementation Method 2
either or both of: applying vacuum to fluid in contact with the first non-forming surface; and/or applying positive pressure to the slurry composition in contact with the first forming surface, thereby drawing or urging the slurry composition to the first forming surface, and drawing or urging a portion of the carrier fluid in the quantity through the first pattern of ports
Implementation Method 3
applying opposing force between the third forming tool and the fourth forming tool along the third and fourth longitudinal axes, thereby applying pressure on the second formation between the third forming surface and the fourth forming surface, whereby a third remaining portion of the carrier fluid is driven from the second formation, and whereby the second formation is transformed into a third formation
Data Source
AI summary
A method for forming structures of cellulose fiber, and in one particular example, for forming structures with features that have facing, near-parallel or parallel walls or surfaces. In one particular but non-limiting example, nearly-cylindrical or cylindrical tampon applicator components molded of cellulose fiber, as an alternative to plastic, is present.