Pulp Molding Tool Slit Opening and Mesh Design

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Solution Overview

Problem

Porous molding tools used in pulp molding often become clogged due to fibers entering the vacuum passages, leading to poor suction function, uneven fiber layers, and the need for frequent and time-consuming cleaning.

Innovation Solution

A molding tool with a mold body featuring suction channels that include slit openings at the intersection of vertical sidewalls and horizontal flanges, allowing for continuous vacuum flow with both horizontal and vertical directions, and a water-permeable mesh to retain pulp fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If porous molding tools are used for water removal during pulp molding, then water removal efficiency is improved, but the tools become clogged by fibers entering the vacuum passages

Engineering Contradiction:
Improvewater removal efficiencyVSAvoidsuction function
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A water-permeable mesh is introduced as an intermediary layer between the pulp slurry and the suction channels. This mesh allows water to pass through to the suction channels while blocking fibers from entering and clogging the passages, thus maintaining both water removal efficiency and reliable suction function

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The use of a water-permeable mesh with controlled porosity enables selective permeability - allowing water molecules to pass through while retaining larger fiber particles. This porous structure maintains efficient water removal while preventing fiber intrusion into the vacuum passages

Inventive Principle:
Principle #31Porous materials

2Productivity

If porous molding tools are used for water removal, then drying efficiency is improved, but frequent and time-consuming cleaning is required

Engineering Contradiction:
Improvedrying efficiencyVSAvoidcleaning time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The water-permeable mesh serves as a sacrificial intermediary that captures fibers during the molding process. Since the mesh is removable and replaceable, it can be quickly swapped out when clogged, avoiding the need for time-consuming cleaning of the entire molding tool while maintaining high drying efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mesh is designed to be disposable or easily replaceable. When the mesh becomes clogged with fibers, it can be quickly removed and replaced with a fresh mesh, minimizing downtime and cleaning requirements while maintaining consistent drying performance

Inventive Principle:
Principle #34Discarding and recovering

3Productivity

If porous molding tools are used, then water removal is enhanced, but uneven and inferior fiber layers result when clogging occurs

Engineering Contradiction:
Improvewater removal rateVSAvoidfiber layer uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The water-permeable mesh acts as a uniform intermediary layer that ensures consistent water removal across the entire molding surface. By preventing fiber clogging of the suction channels, the mesh maintains uniform suction distribution, which in turn produces even and high-quality fiber layers throughout the molded product

Inventive Principle:
Principle #24Intermediary (Mediator)

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 tool prevents clogging, simplifies cleaning, and ensures an even fiber layer across the entire product, reducing waste and enabling the production of high-quality molded fiber articles with increased productivity.

Implementation Method 1

suction channels arranged to generate a suction at the surface of the forming side upon coupling the mold body to a vacuum suction source during use

Methodology Applied
Scientific EffectVacuum suction: Vacuum

Implementation Method 2

a water-permeable mesh arranged to retain pulp fibers

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP4545704A1A tool for wet molding a fiber-based product
Publication Date: 2025.04.30 STORA ENSO OYJ
  • EP4545704A1 patent drawingFigure 1a~1b
  • EP4545704A1 patent drawingFigure 2a~2b
  • EP4545704A1 patent drawingFigure 2c~2d

AI summary

The present invention relates to a tool for use in a process of molding a product from a fibrous pulp slurry, said tool comprising: -a mold body having a three-dimensional forming side comprising at least one bottom section, essentially vertical sidewalls surrounding said bottom section, and a flange extending horizontally from an upper portion of said sidewalls; said mold body comprising a plurality of suction channels evenly distributed across said forming side and arranged to generate a suction at the surface of the forming side upon coupling the mold body to a vacuum suction source during use; wherein at least one of said suction channels comprises a slit opening located at the intersection between the essentially vertical sidewall and the horizontal flange, such that said slit opening is facing both said vertical sidewall and said horizontal flange. The present invention also relates to a method for producing a molded product.