Microwave Graphitization Module for High Modulus Carbon Fiber
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Solution Overview
Problem
Conventional high modulus carbon fiber manufacturing processes are inefficient and costly due to slow heat conduction, long processing times, and high energy consumption, making mass production difficult and expensive.
Innovation Solution
A manufacturing device comprising a low-temperature furnace, microwave graphitization module, and gluing module, with tension wheel sets and a thermal bake-dry module, utilizing a microwave cavity with a wave absorbing structure and inert gas supply to rapidly graphitize carbon fibers at lower temperatures, reducing processing time and energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional thermoelectric furnace graphitization is used, then fiber strength is maintained, but processing time exceeds 1-10 hours and energy consumption is high
Solution Approach 1:
The patent replaces the conventional thermoelectric furnace heating system with a microwave heating system. The microwave graphitization module uses electromagnetic radiation to directly heat the carbon fiber precursors, eliminating the need for external thermal conduction through furnace walls. This substitution enables rapid graphitization at lower temperatures (below 3000°C) while reducing processing time from 1-10 hours to minutes, and significantly lowering energy consumption.
Solution Approach 2:
The patent changes the heating parameters by using microwave radiation instead of conventional thermal conduction. The microwave system operates at specific frequencies that resonate with water molecules and polar molecules in the precursor material, generating internal heat directly within the fiber structure. This parameter change allows graphitization to occur at lower temperatures and much faster rates compared to traditional furnace methods.
2Manufacturing precision
If graphitization temperature is increased to improve modulus, then tensile modulus increases, but fiber strength drops significantly
Solution Approach 1:
The patent changes the graphitization temperature parameter from conventional high temperatures (2000-3000°C) to lower temperatures (below 3000°C, typically 2500-2800°C). The microwave heating method achieves effective graphitization at these lower temperatures by providing rapid, uniform internal heating. This parameter change produces fibers with tensile modulus of 350-600 GPa while maintaining fiber strength above 3.5 GPa, resolving the trade-off between modulus and strength.
Solution Approach 2:
The replacement of conventional furnace heating with microwave heating enables better control over the heating rate and temperature distribution. The microwave system provides rapid heating that limits the time at peak temperature, reducing thermal degradation while achieving the necessary graphitization. This substitution allows obtaining high modulus fibers with preserved strength.
3Stability of the object's composition
If conventional furnace heating is used, then uniform heating is achieved, but heat conduction is slow and insulation requirements are high
Solution Approach 1:
The patent substitutes conventional thermal conduction heating with microwave electromagnetic heating. The microwave system penetrates the precursor material and generates heat internally throughout the fiber structure simultaneously, eliminating the slow external-to-internal heat conduction process. This substitution achieves uniform heating distribution while reducing heating time from hours to minutes, and eliminates the need for complex insulation systems.
Solution Approach 2:
The microwave heating system enables the material to heat itself through dielectric loss and molecular vibration. The precursor fibers absorb microwave energy and convert it to heat internally, serving as their own heating source. This self-heating mechanism ensures uniform temperature distribution throughout the fiber cross-section and length, eliminating thermal gradients and insulation requirements.
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
Enables continuous mass production of high modulus graphite fibers with enhanced graphitization efficiency and reduced costs, achieving tensile moduli of 270-650 GPa and crystal structures with thicknesses of 20-70 angstroms, suitable for advanced composite materials.
Implementation Method 1
a low-temperature furnace (30), a microwave graphitization module (40) and a gluing module (50) sequentially installed between the material supply module (10) and the winding machine (20)... through the microwave graphitization module (40) to perform a graphitization of the raw material of the carbon fibers
Implementation Method 2
a microwave cavity with a wave absorbing structure
Implementation Method 3
the raw material of the carbon fibers passes through the low-temperature furnace to remove a protective film on the surface of the raw material of the carbon fiber
Implementation Method 4
through the gluing module to perform a gluing process of the graphite fiber semi-finished good to produce a high modulus graphite fiber finished good
Data Source
AI summary
A manufacturing device includes a material supply module, a winding machine as well as a low-temperature furnace, a tension wheel set, a microwave graphitization module and a gluing module sequentially installed between the material supply module and the winding machine, so that a carbon fiber raw material can be manufactured continuously in mass production to enhance the graphitization efficiency and lower the process cost significantly.