Fibrous Forming Tool Geometry 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, leading 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, each with its own pair of forming tools. The first pair forms the basic structure, while subsequent pairs add specific 3D features with parallel walls. This segmentation allows each step to be optimized for its specific function, avoiding the shearing and friction problems that would occur in a single-step process.
Solution Approach 2:
The basic structure of the container is formed first using the first pair of forming tools, creating a preliminary form that can then serve as the foundation for adding additional 3D features. This preliminary action establishes the main body before attempting to form the problematic parallel-walled features, thereby avoiding defects.
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 3D features with facing parallel walls can be formed, but substantial complexity and cost are introduced to the equipment and process
Solution Approach 1:
Each pair of forming tools is designed to perform multiple functions: forming the container body, creating openings, and forming 3D features with parallel walls. The forming surfaces are configured with various geometric features that can create different structures depending on the compression direction and force applied, eliminating the need for specialized tools for each feature type.
Solution Approach 2:
The forming process uses controlled compression forces that can be dynamically adjusted in magnitude and direction. The forming tools apply pressure progressively, allowing the pulp agglomeration to be shaped into complex 3D features with parallel walls through controlled deformation rather than requiring complex multi-tool mechanisms.
3Force
If forming tools have facing forming surfaces parallel with the forming direction, then compression can be applied efficiently, but shearing friction between the surfaces and pulp agglomeration causes defects
Solution Approach 1:
The forming surfaces are designed with asymmetric features including angled surfaces, curved surfaces, and non-parallel facing surfaces. These asymmetric geometries allow compression forces to be applied efficiently while directing the pulp flow in controlled patterns that minimize shearing and friction, thereby maintaining high formation quality.
Solution Approach 2:
Curved and rounded forming surfaces are used instead of sharp parallel planes. The curved surfaces distribute compression forces more evenly across the pulp agglomeration, reducing localized shearing and friction that would cause defects. The gradual curvature allows the pulp to deform smoothly into the desired 3D features with parallel walls.
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
The second forming tool may have a configuration and second forming surface that mates or cooperates with the first forming surface, with a suitable clearance therebetween, to express carrier fluid from the agglomeration, further shape the agglomeration and compress and densify the fibers
Implementation Method 3
If desired, heating energy may be provided to one or both of the first forming tool and second forming tool to cause evaporation of carrier fluid and/or impart a set to the fibers, and thereby add stiffness and strength to the structure
Data Source
AI summary
A forming tool for agglomerating thereon fibers from a slurry, the tool having a first end, a second end, a longitudinal axis, a forming surface and a non-forming surface, wherein the forming surface is perforated with a pattern of fluid passage ports extending from the forming surface to the non-forming surface; wherein the pattern of fluid passage ports demarks a surface area of the forming surface.