Actinically Curable Composites for Additive Manufacturing
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Solution Overview
Problem
The challenge lies in producing actinically curable compositions suitable for additive manufacturing of ablative composites with opaque reinforcements, which are difficult due to the opaque nature of materials like carbon fibers, limiting the production of high-temperature composites used in aerospace and energy applications.
Innovation Solution
A curable composition comprising aromatic actinically curable components, actinically curable monomers, opaque reinforcements, and photoinitiators, designed to achieve high carbon yield and adequate green-strength for pyrolysis, using (meth)acrylated epoxy novolak resins and reactive diluents, and employing actinic radiation for curing, enabling the production of carbon-bonded composites with enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional hand-laying and mold fabrication methods are used for carbon bonded composites, then the composite structure can be formed, but the manufacturing process becomes labor-intensive, time-consuming, and expensive
Solution Approach 1:
The patent replaces traditional mechanical hand-laying and mold-based fabrication with additive manufacturing technology, enabling automated deposition of composite materials layer-by-layer to form complex geometries without manual intervention or large molds
Solution Approach 2:
The patent changes the manufacturing approach from subtractive machining of large blocks to additive construction, fundamentally altering the production parameters and enabling direct fabrication of final-shaped components with optimized material distribution
2Reliability
If traditional oven heating and resin saturation methods are used, then the composite can be cured, but the process requires multiple heating cycles and extensive time
Solution Approach 1:
The patent incorporates photoinitiators and actinically curable resins into the composite material before printing, enabling the curing process to be initiated and completed locally and rapidly through UV light exposure during or immediately after deposition, rather than requiring subsequent extended oven heating cycles
Solution Approach 2:
The patent replaces thermal curing (oven heating) with photopolymerization (UV light curing), substituting a slow thermal process with a rapid optical process that achieves complete curing in seconds or minutes rather than hours
3Strength
If opaque reinforcements like carbon fibers are used in traditional composites, then the composite achieves high strength and heat resistance, but actinic radiation cannot penetrate to cure the resin
Solution Approach 1:
The patent transitions from bulk curing (requiring UV penetration through the entire thickness) to surface-layer-by-layer curing during additive manufacturing, where each deposited layer is cured in place before the next layer is added, eliminating the need for UV penetration through opaque reinforcements
Solution Approach 2:
The patent performs curing of each layer immediately after deposition while the material is still in place, rather than attempting to cure the entire composite structure after complete assembly, enabling successful curing despite the presence of opaque reinforcements
4Shape
If complex geometries are produced using traditional subtractive machining, then the final shape can be achieved, but the process is difficult due to hardness and brittleness of the composite material
Solution Approach 1:
The patent inverts the traditional manufacturing sequence by adding material layer-by-layer to build the final shape directly, rather than starting with a large block and removing material through machining, thereby eliminating the difficulty of machining hard and brittle composite materials
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 allows for the efficient production of carbon-bonded composites with high char yield and improved mechanical properties, reducing manufacturing time and cost while enabling the creation of complex geometries, overcoming the limitations of traditional fabrication methods.
Implementation Method 1
actinically curable compositions... include at least one photoinitiator... employing actinic radiation for curing
Implementation Method 2
After curing and upon pyrolysis, the actinically cured ablative composite may be capable of creating more than 18 weight % char
Data Source
AI summary
An actinically curable composition includes at least one aromatic, actinically curable component a), at least one actinically curable monomer b) as a diluent, an opaque reinforcement c) and at least one photoinitiator d). After curing and upon pyrolysis, the actinically curable composition may provide more than 18 weight % char, by weight of the component a), the actinically curable monomer b) and the photoinitiator d) after curing. The opaque reinforcement may be continuous fibers. A method of making a three dimensionally printed carbon bonded composite article from the actinically curable composition using digital light projection, stereolithography or multi jet printing is also provided.