Composite Filament 3D Printing with Ironing Force

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Solution Overview

Problem

Current 3D printing technologies face challenges in efficiently generating toolpaths for composite filament fabrication, particularly in creating complementary toolpaths that avoid stress concentrations and seam accumulation between layers, which affects the structural integrity and consistency of printed parts.

Innovation Solution

A method involving the use of multi-strand core reinforced filaments with substantially continuous reinforcing strands, where composite swaths are deposited with an ironing force to spread the strands, allowing for the creation of consolidated composite swaths with reinforcing strands oriented parallel to the filament length, and toolpaths are controlled to overlap and interact in specific patterns to distribute stress and reinforce layers effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional toolpaths are used for composite filament fabrication, then the printing process is simple, but stress concentrations and seam accumulation occur between layers affecting structural integrity

Engineering Contradiction:
Improvestructural integrityVSAvoidtoolpath complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The toolpath is divided into multiple segments including primary reinforcement paths, secondary reinforcement paths, and transition regions. Each segment serves a specific function in distributing stress and avoiding seam accumulation, thereby improving structural integrity without requiring overly complex integrated toolpaths

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a third dimension to toolpath planning by considering inter-layer reinforcement patterns. Secondary reinforcement paths are placed in adjacent layers at different orientations to complement the primary reinforcement, creating a three-dimensional reinforcement structure that distributes stress more effectively

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If reinforcing strands are spread against deposition surface with ironing force, then fiber distribution is improved, but the process complexity increases

Engineering Contradiction:
Improvefiber distributionVSAvoiddeposition process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The ironing process utilizes the material's own properties - the heat and pressure from the deposition head itself spread the reinforcing strands and consolidate the matrix material. This self-consolidating mechanism improves fiber distribution without requiring additional external consolidation equipment

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent controls the ironing force parameters (pressure, temperature, dwell time) to optimize fiber distribution. By adjusting these parameters during deposition, the process achieves precise control over strand spreading and consolidation while maintaining a relatively simple single-pass deposition operation

Inventive Principle:
Principle #35Parameter changes

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 enhances the structural integrity and consistency of printed parts by reducing stress concentrations and seam accumulation, improving the distribution of reinforcing fibers across layers, leading to stronger and more reliable 3D printed structures.

Implementation Method 1

applying an ironing force that spreads the reinforcing strands within the filament against a deposition surface

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

flowing the matrix material and applying an ironing force that spreads the reinforcing strands

Methodology Applied
Scientific EffectViscous Flow:

Data Source

PatentEP3221129B1Composite filament 3D printing using complementary reinforcement formations
Publication Date: 2022.10.19 MARKFORGED INC
  • EP3221129B1 patent drawingFigure 1A
  • EP3221129B1 patent drawingFigure 1B
  • EP3221129B1 patent drawingFigure 1C

AI summary

In a method for additive manufacturing, a multi- strand core reinforced filament including a flowable matrix material and substantially continuous reinforcing strands extending in a direction parallel to a length of the filament is supplied. A first consolidated composite swath of a height less than ½ the width of the filament is deposited in a first reinforcement formation including at least one straight path and at least one curved path against a deposition surface, and a second consolidated composite swath of a height less than ½ the width of the filament is deposited in a second reinforcement formation against the first consolidated composite swath. Each deposition flows the matrix material and applies an ironing force to spread the reinforcing strands within the filament against the underlying surface and/or previously deposited swath.