3D-Printed High-Temperature Composite Structures With Pyrolysis Densification
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Solution Overview
Problem
Conventional methods for fabricating high-temperature composite structures, such as carbon-carbon (C/C) and ceramic matrix composite (CMC) structures, are labor-intensive, costly, and time-consuming, often requiring intricate processes that involve forming multiple parts and extensive machining, which can introduce defects and are not suitable for forming complex structures with void spaces.
Innovation Solution
A method involving 3D printing of precursor structures using a robotic system to deposit filament materials with embedded fibers, followed by pyrolysis and impregnation with a liquid resin, allowing for the formation of high-temperature composite structures with oriented fibers and void spaces, such as sandwich structures, through a near-net-shape process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fabrication techniques are used to form high-temperature composite structures, then structural integrity and material properties can be achieved, but the process becomes labor-intensive, costly, and time-consuming
Solution Approach 1:
The patent changes the physical and chemical parameters of the material throughout the process. The precursor material undergoes pyrolysis to transform from an organic polymer to a carbon-rich matrix, then further transforms to a ceramic matrix through chemical vapor deposition. These parameter changes enable the formation of high-temperature composite structures with improved structural integrity while reducing production time compared to conventional methods.
Solution Approach 2:
The patent performs preliminary actions by first forming a green body structure using 3D printing with precursor materials, then systematically applying multiple impregnation and pyrolysis cycles. This preliminary structuring allows subsequent densification steps to efficiently achieve the final high-temperature composite structure, significantly reducing the overall production time and labor requirements compared to conventional fabrication.
2Reliability
If conventional fabrication techniques are used, then composite material properties can be achieved, but extensive machining and assembly of multiple parts are required
Solution Approach 1:
The patent merges multiple fabrication steps into an integrated additive manufacturing process. The 3D printing system combines material deposition, fiber embedding, and structural formation in a single process, eliminating the need for separate machining and assembly operations. Multiple impregnation and pyrolysis cycles are combined to simultaneously achieve densification and material property development, reducing process complexity while maintaining material properties.
Solution Approach 2:
The patent transitions from conventional 2D layer-by-layer lamination to true 3D additive manufacturing with multi-axis fiber deposition. This dimensional change enables complex internal geometries, void spaces, and fiber orientations to be directly formed during printing, eliminating the need for extensive machining and assembly of multiple parts while maintaining the required composite material properties.
3Shape
If 3D printing with filament material is used to form precursor structures, then complex geometries and void spaces can be created, but porosity is introduced that must be reduced
Solution Approach 1:
The patent employs periodic action through multiple cycles of impregnation and pyrolysis. Each cycle consists of impregnating the green body with precursor material, followed by pyrolysis to densify the structure. This periodic repetition of impregnation and heating cycles systematically reduces porosity while preserving the complex geometry and void spaces created by the 3D printing process, achieving the required manufacturing precision.
Solution Approach 2:
The patent utilizes parameter changes during the pyrolysis process, where temperature, pressure, and atmospheric conditions are systematically varied across multiple cycles. These parameter changes transform the porous green body into a dense ceramic matrix composite structure, reducing porosity to acceptable levels while maintaining the complex geometry and intentional void spaces that provide structural functionality.
4Manufacturing precision
If multiple impregnation and pyrolysis cycles are used to densify the structure, then porosity is reduced and material properties improve, but production time increases
Solution Approach 1:
The patent maintains continuity of useful action by overlapping and parallelizing certain process steps. Multiple impregnation and pyrolysis cycles are performed in sequence, but each cycle is optimized to minimize idle time. The 3D printing process continuously deposits material while the impregnation process continuously penetrates the green body, and pyrolysis continuously densifies the structure. This continuous action reduces the total cycle time while achieving the required density and material properties.
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 method enables the production of high-temperature composite structures with low porosity, oriented fibers, and complex void spaces as integral pieces, reducing the need for extensive machining and lowering production time and costs while maintaining structural integrity.
Implementation Method 1
A robotic system is used to deposit a filament material that includes a precursor matrix material having embedded therein a fiber material
Implementation Method 2
The 3D printed precursor structure is pyrolyzed to form a porous intermediate structure
Implementation Method 3
The porous intermediate structure is impregnated with a liquid resin
Implementation Method 4
The impregnated structure is exposed to a high-temperature environment to solidify material from the liquid resin within pores of the pyrolyzed intermediate structure
Data Source
AI summary
Methods for fabricating high-temperature composite structures (e.g., structures comprising carbon-carbon composite materials or ceramic composite matrix (CMC) materials and configured for use at temperature at or exceeding about 2000° F. (1093° C.)) include forming precursor structures by additive manufacturing (“AM”) (e.g., “3D printing”) with a filament drawn from a spool. The precursor structures are exposed to high temperatures to pyrolyze a precursor matric material of the initial 3D printed structure. A liquid resin is used to impregnate the pyrolyzed structure, to densify the structure into a near-net final shape. Use of expensive and time-consuming molds and post-processing machining may be avoided. Large, unitary, integrally formed parts conducive for use in high-temperature environments may be formed using the methods of the disclosure.