SiC Fiber Precursor Crosslinking with Platform Temperature Control
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Solution Overview
Problem
The current e-beam crosslinking process for silicon carbide fiber polymer precursors is limited by temperature increases due to radiation absorption, leading to high production costs and low throughput, as the fibers must be cooled and re-exposed to radiation multiple times to prevent melting and maintain dimensional integrity.
Innovation Solution
A method and apparatus that utilize active temperature regulation and translation of the platform or e-beam radiation to deliver higher dose rates of e-beam radiation while maintaining the fiber temperature below the softening point, eliminating the need for a cooling conveyor system and reducing capital investment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If e-beam radiation is used to crosslink SiC fiber polymer precursors, then crosslinking effectiveness is improved, but temperature increase causes the fibers to reach melting point and lose dimensional integrity
Solution Approach 1:
The patent applies periodic action by delivering e-beam radiation in multiple small doses rather than a single large dose. The fiber is irradiated, then cooled via conveyor before receiving the next dose, repeating this cycle until cumulative crosslinking is achieved. This periodic approach prevents temperature from reaching the melting point while still achieving effective crosslinking over time.
Solution Approach 2:
The patent uses preliminary action by cooling the fiber between radiation doses through ambient atmosphere exposure during conveyor transport. This preliminary cooling action prepares the fiber to receive the next radiation dose without exceeding temperature limits, enabling multiple doses to be delivered safely.
2Stability of the object's composition
If multiple small doses of radiation are delivered with cooling between doses, then dimensional integrity is maintained, but production throughput becomes prohibitively slow and expensive
Solution Approach 1:
The patent applies parameter changes by modifying the cooling mechanism from passive ambient atmosphere cooling to active cooling using cold gas or liquid nitrogen. This parameter change in the cooling method enables much faster heat removal, allowing multiple radiation doses to be delivered in rapid succession without sacrificing dimensional integrity, thereby dramatically increasing throughput.
Solution Approach 2:
The patent achieves continuity of useful action by eliminating idle cooling time between radiation doses. Through active cooling, the fiber is rapidly cooled and immediately ready for the next dose, making the overall process continuous rather than intermittent. This eliminates the slow conveyor-based cooling step while maintaining dimensional integrity.
3Temperature
If a long conveyor system is used to cool fibers between radiation doses, then temperature control is achieved, but capital investment and production time become prohibitively large
Solution Approach 1:
The patent applies taking out by extracting the cooling function from the conveyor system itself. Instead of using a long conveyor to provide passive cooling over distance, the invention separates cooling into an independent active cooling step using cold gas or liquid nitrogen. This eliminates the need for a long conveyor system while achieving the same temperature control objective.
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 enables a significant increase in throughput, achieving 500% to 600% higher production rates of crosslinked preceramic SiC fibers with improved radiation dose uniformity and reduced capital investment, while maintaining the fibers' dimensional integrity.
Implementation Method 1
exposing a first portion of silicon carbide fiber precursor polymer provided on a platform to e-beam radiation from an e-beam radiation mechanism
Implementation Method 2
crosslinking a silicon carbide fiber precursor polymer
Implementation Method 3
regulating the temperature of the platform to thereby prevent the temperature of the first and second portions of the carbide fiber precursor polymer from reaching their softening point due to the e-beam radiation
Implementation Method 4
regulating the temperature of the platform
Data Source
AI summary
The present disclosure generally provides methods and apparatus for efficiently crosslinking silicon carbide fiber precursor polymers with electron beam radiation. The methods and apparatus utilize a platform containing silicon carbide fiber precursor polymer. The temperature of the platform is regulated while the silicon carbide fiber precursor polymer is irradiated to thereby regulate the temperature of the irradiated silicon carbide fiber precursor polymer thereon. In this way, the temperature of the irradiated silicon carbide fiber precursor polymer is regulated via the platform both during and after it is subjected to radiation. At least one of the platform and the e-beam radiation mechanism may be translated with respect to the other to irradiate different portions of the silicon carbide fiber precursor polymer and, ultimately, the entirety of the silicon carbide fiber precursor polymer contained on the platform.