3D Printed Pulp Mold Surface for Fiber-Blocking Vacuum Flow

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Solution Overview

Problem

Existing 3D printed molds for vacuum forming objects from aqueous pulp slurry suffer from fiber ingress during negative pressurization, leading to clogging and rendering the molds ineffective.

Innovation Solution

The use of additive manufacturing techniques to create molds with a product surface featuring intentionally placed beads at the ends of transverse filaments, forming narrow pores that prevent fiber ingress while allowing fluid passage, combined with an infill polymer layer for stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If 3D printed molds are used for vacuum forming, then manufacturing flexibility and design freedom are improved, but fiber ingress into the mold interior occurs during negative pressurization

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoidfiber ingress

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating beads at specific locations (ends of transverse filaments) on the mold surface. These beads are not uniformly distributed but strategically placed to control pore size and prevent fiber ingress only where needed, while maintaining the overall 3D printed mold structure's flexibility and design freedom.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes porous materials by creating a controlled porous structure through the bead formation process. The beads create narrow pores that allow fluid passage during vacuum forming while preventing fiber ingress. This porous structure is intentionally designed with specific pore size characteristics to resolve the contradiction between permeability and fiber prevention.

Inventive Principle:

Principle #31Porous materials

2Productivity

If porous structure is created to allow fluid passage, then vacuum formation efficiency is improved, but fiber clogging of the mold interior occurs

Engineering Contradiction:

Improvevacuum formation efficiencyVSAvoidmold functionality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies porous materials principle by creating a controlled porous structure where beads form narrow pores. These pores are sufficiently small to prevent fiber clogging yet large enough to allow efficient fluid passage during vacuum formation. The porosity is intentionally designed to balance productivity and reliability.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent converts the potential harm of porous structures (which could allow fiber ingress) into a benefit by using the beads to create controlled narrow pores. The same porous structure that enables vacuum formation efficiency is designed to prevent fiber clogging, turning a potential problem into a solution.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If bead structure is added to prevent fiber ingress, then mold functionality is maintained, but manufacturing complexity increases

Engineering Contradiction:

Improvemold functionalityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent reduces manufacturing complexity by applying local quality - beads are created only at specific locations (ends of transverse filaments) rather than throughout the entire mold structure. This localized approach maintains mold functionality while minimizing the added manufacturing complexity compared to a fully porous or uniformly structured mold.

Inventive Principle:

Principle #3Local quality

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

Prevents fiber clogging, enabling efficient vacuum formation of three-dimensional objects by ensuring fibers accumulate on the mold surface rather than entering the interior matrix, thus maintaining mold functionality.

Implementation Method 1

a vacuum system coupled to the mold... wherein negative pressure is applied to the mold by the vacuum system coupled to the mold

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

the pores are configured to prevent the ingress of a fiber into the interior matrix of the mold

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentUS12480257B23D printed tooling for pulp molding process

Publication Date: 2025.11.25 PAPACKS SALES GMBH

AI summary

The present invention is directed to a 3D printed mold for creating three dimensional pulp products from a fibrous pulp slurry. Transverse filaments are integrated into an infill structure with an open-cell pattern. The transverse filaments form channels through the interior matrix of the mold. The open cell infill pattern and channels allow for the movement of vacuumed materials through the interior matrix of the 3D printed mold when vacuum pressure is applied. The product surface of the mold comprises an array of beads formed from the over-extrusion of melted material at the ends of the transverse filaments. The beaded array narrows the opening of the channels created by the transverse filaments, preventing the fibers from entering the matrix of the mold and clogging the flow of materials. This causes the fibers to aggregate on the product surface of the mold, forming the three dimensional pulp product.