Pulp Molding Process Using Composite Fiber Lengths
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Solution Overview
Problem
Conventional pulp molding processes face issues with crosslinking effects, resulting in rough surface smoothness, mechanical weakness, and low manufacturing efficiency, particularly when shaping narrow or deep cavities, which affects the yield and aesthetics of paper-shaped objects.
Innovation Solution
A pulp molding process utilizing a composite of superior short fiber materials and relatively longer fibers, combined with pre-compression forming and compression thermo-forming steps, to prevent crosslinking and enhance surface smoothness and strength, with specific fiber length and weight ratios, and the inclusion of additives like water retention and paper strength agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If long-length fibers (over 2 mm) are used in wet paper slurry, then the mechanical strength of the paper-shaped object is improved, but crosslinking effect occurs in narrow/tiny cavities causing rough surface and structural damage
Solution Approach 1:
The patent applies different fiber length specifications to different regions of the paper-shaped object. Long-length fibers (over 2 mm) are used in general areas to provide mechanical strength, while short-length fibers (1-2 mm) are specifically applied to narrow/tiny cavities to prevent crosslinking. This local differentiation resolves the contradiction between strength and surface quality in different regions.
Solution Approach 2:
The patent changes the fiber length parameter based on the specific application area. By adjusting the fiber length from over 2 mm in general areas to 1-2 mm in narrow cavities, the patent optimizes both mechanical strength and surface smoothness, preventing crosslinking effects while maintaining overall structural integrity.
2Manufacturing precision
If short-length fibers (1.4-2 mm) are used to reduce crosslinking effect, then surface smoothness is improved, but the mechanical strength of the paper-shaped object becomes weak
Solution Approach 1:
The patent applies different fiber length specifications to different regions of the paper-shaped object. Long-length fibers (over 2 mm) are used in general areas to provide mechanical strength, while short-length fibers (1-2 mm) are specifically applied to narrow/tiny cavities to prevent crosslinking. This local differentiation resolves the contradiction between strength and surface quality in different regions.
Solution Approach 2:
The patent creates a composite fiber structure by combining long-length fibers (over 2 mm) and short-length fibers (1-2 mm) in the wet paper slurry. The composite provides both the mechanical strength from long fibers and the crosslinking prevention from short fibers, achieving a balance between strength and surface smoothness.
3Ease of manufacture
If conventional pulp molding process is used with single fiber type, then the manufacturing process is simple, but the yield of paper-shaped objects decreases due to crosslinking effect and structural damage
Solution Approach 1:
The patent creates a composite fiber structure by combining long-length fibers (over 2 mm) and short-length fibers (1-2 mm) in the wet paper slurry. The composite provides both the mechanical strength from long fibers and the crosslinking prevention from short fibers, achieving a balance between strength and surface smoothness.
4Manufacturing precision
If conventional molding process with over 200 seconds cycle time is used, then thorough forming is achieved, but manufacturing efficiency for mass production becomes very low
Solution Approach 1:
The patent performs preliminary action by pre-dredging the wet pulp body with appropriate fiber composition before the main molding process. This preliminary preparation ensures that the fiber structure is optimized for both strength and surface quality, allowing the subsequent molding process to be completed more quickly while maintaining high forming quality, thus reducing the overall cycle time.
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 process effectively eliminates crosslinking effects, achieving smooth surfaces and improved mechanical strength, reducing production time, and enhancing the aesthetic appeal of paper-shaped articles while maintaining high manufacturing efficiency.
Implementation Method 1
a pulp-dredging step of dredging a wet pulp body made of the composite, by one of a first upper mold and a first lower mold, from a slurry tank carrying a paper slurry containing of the composite
Implementation Method 2
performing a first pre-compression forming step on the wet pulp body to form at least one first semi-finished product with a first cave on a surface thereof, by and between the first upper mold and the first lower mold
Implementation Method 3
performing a compression thermo-forming step on the at least one first semi-finished product to form at least one second semi-finished product
Implementation Method 4
performing a compression thermo-forming step on the at least one first semi-finished product to form at least one second semi-finished product
Data Source
AI summary
A pulp molding process and a paper-shaped article made thereby are provided. The pulp molding process comprises the steps of providing a composite having at least one fiber material, performing a pulp-dredging step including a first pre-compression forming step, performing a compression thermo-forming step, and performing an edge-cutting step for forming a paper-shaped article, wherein the composite comprises 20 to 99 parts by weight of a superior short fiber material for forming the paper-shaped article for eliminating the crosslinking effect. The paper-shaped article made by the pulp molding process comprises a cave having a transversal width of from 0.5 mm to 8 mm.