Porous Pulp Molding Tool Wall for Uniform Vacuum Distribution
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Solution Overview
Problem
Existing pulp molding dies face challenges such as distortion, rupture, high cost, limited complexity, and trade-offs between surface quality and pressure drop, as well as limitations in temperature resistance and durability.
Innovation Solution
A self-supporting tool with straight or curved channels extending through the tool wall, providing efficient vacuum distribution and reduced energy consumption, while maintaining a durable and cost-effective molding process capable of withstanding elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wire cloth is stretched to conform to a die surface, then the mold can be made, but the wire cloth undergoes distortion and stretching that limits the complexity of products that can be molded
Solution Approach 1:
The patent uses a porous die material with controlled pore distribution instead of stretched wire cloth. The porous structure allows vapor to pass through during molding while the material itself can be formed into complex three-dimensional shapes without the distortion limitations of stretched fabric. This resolves the contradiction by providing both manufacturability and adaptability to complex product geometries.
Solution Approach 2:
The patent employs a composite structure combining a porous die material with specific mechanical properties that allow it to maintain structural integrity while conforming to complex die surfaces. The composite nature enables the die to be manufactured for complex products without the wire cloth stretching and distortion problems.
2Ease of manufacture
If wire cloth is used in the mold, then the mold can be made, but the wire cloth is prone to rupture and difficult to repair
Solution Approach 1:
The porous die material provides structural integrity and resistance to rupture while maintaining the necessary porosity for vapor transmission. Unlike wire cloth that can tear and is difficult to repair, the porous material forms a monolithic structure that is more durable and reliable for repeated molding cycles.
3Ease of manufacture
If wire cloth is stretched to conform to a die surface, then the mold can be made, but the pores of the wire cloth are deformed and the distribution of openings cannot be controlled
Solution Approach 1:
The porous die material is manufactured with controlled pore distribution directly into the material structure, rather than relying on the natural openings of wire cloth. This allows precise control over pore size, shape, and distribution to optimize vapor transmission while maintaining structural integrity for complex product formation.
4Ease of manufacture
If wire cloth is used in the mold, then the mold can be made, but it is necessary to provide a metal backing which increases cost
Solution Approach 1:
The porous die material itself provides the necessary structural support and vapor transmission function, eliminating the need for a separate metal backing structure. This integrated solution reduces overall mold complexity and cost while maintaining the ability to form complex products.
5Manufacturing precision
If finer particles are used at the surface of the die, then surface quality improves, but the channels become smaller and pressure drop increases
Solution Approach 1:
The porous die material allows for local variation in pore size and distribution, with finer pores at the surface for quality and larger pores internally for low pressure drop. This gradient structure optimizes both surface quality and vapor transmission efficiency, resolving the trade-off between these two parameters.
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 solution enhances vacuum distribution, reduces energy requirements, and improves the durability and cost-effectiveness of the molding process, allowing for more complex and high-quality product formation.
Implementation Method 1
The channels are straight or curved with no more than one point of inflection... providing efficient vacuum distribution
Data Source
AI summary
The present document discloses a tool or tool part for use in a process of molding a product from a pulp slurry. The tool or tool part comprises a self-supporting tool wall portion having a product face, for contacting the product, and a back face on the other side of the wall relative to the product face. The tool wall portion presenting pores, which are provided by a plurality of channels extending through the tool wall portion, from the product face to the back face. The channels are straight or curved with no more than one point of inflection.