Additive Manufacturing Composite Structures via Photopolymerization

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Solution Overview

Problem

The fabrication of composite materials like carbon-bonded fiber composites (CBFCs) and ceramic matrix composites (CMCs) is labor-intensive, time-consuming, and expensive, limiting their applications due to complex and costly processes that involve hand-laying fibers, resin saturation, and subsequent subtractive machining, which is difficult for hard materials like CMCs.

Innovation Solution

An additive manufacturing system that includes a support and a discharge head configured to discharge a composite material, with a cure enhancer to partially cure the material during discharge, a supply to advance a densifying material, and a heater to pyrolyze the materials, allowing for the creation of composite structures with reduced porosity and machining requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional hand-laying fiber fabrication process is used, then composite structures can be manufactured, but the process is labor-intensive and time-consuming

Engineering Contradiction:

Improvefabrication processVSAvoidproduction efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent replaces manual hand-laying operations with an automated extrusion system that deposits composite material through a digital light processing (DLP) guided process. The extrusion head mechanically deposits material layers while a DLP system cures the resin, eliminating labor-intensive hand operations and significantly improving production efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the state of the composite material from uncured resin to cured solid through controlled photopolymerization. By adjusting the DLP light exposure parameters and extrusion rates, the system achieves optimal curing while maintaining manufacturing automation, thus improving both ease of manufacture and productivity

Inventive Principle:

Principle #35Parameter changes

2Reliability

If traditional resin saturation and pyrolysis process is used, then composite material is formed, but porosity is created requiring multiple iterations

Engineering Contradiction:

Improvecomposite material qualityVSAvoidfabrication time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary curing of the composite material during the deposition process itself through DLP photopolymerization. This preliminary action prevents porosity formation before it occurs, eliminating the need for multiple pyrolysis iterations and reducing total fabrication time while maintaining material quality

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuous curing action through the DLP system as material is being extruded. This continuous useful action ensures complete resin saturation and curing without gaps that would create porosity, achieving high reliability in a single continuous process rather than multiple iterative cycles

Inventive Principle:

Principle #20Continuity of useful action

3Manufacturing precision

If subtractive machining is applied to hard composite materials like CMCs, then desired net shape is achieved, but the machining is difficult and costly

Engineering Contradiction:

Improvenet shape accuracyVSAvoidmachining difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent inverts the traditional manufacturing approach by using additive manufacturing (extrusion and curing) instead of subtractive machining. Rather than creating a rough shape and removing material, the system directly deposits and cures material to achieve the desired net shape, eliminating machining difficulty while maintaining precision

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces mechanical machining operations with a DLP-based photopolymerization system. The DLP projector cures resin in place to create precise geometries directly, substituting difficult mechanical machining of hard CMC materials with a more easily controlled light-based curing process that achieves the same net shape accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method enables the fabrication of composite structures with reduced porosity and machining needs, resulting in cost-effective and efficient production of high-quality composite components for high-temperature applications, such as aerospace and nuclear components, without the need for extensive subtractive machining.

Implementation Method 1

a cure enhancer configured to at least partially cure the composite material at discharge

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

a heater configured to pyrolize the densifying material

Methodology Applied

Scientific EffectPyrolysis: Pyrolysis

Data Source

PatentUS11548220B2Additive manufacturing system and method

Publication Date: 2023.01.10 CONTINUOUS COMPOSITES INC

AI summary

A method is disclosed for additively manufacturing a composite structure. The method may include discharging a composite material from a print head and moving the print head during discharging to fabricate a preform from the composite material. The method may also include densifying the preform with a densifying material, and heating the preform to pyrolize the at least one of the composite material and the densifying material.