Composite Filament Manufacturing via Reactive Thermoplastic Resin Impregnation
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Solution Overview
Problem
Existing composite filaments made with thermoset resin-based binders face limitations in hot formability, compatibility with thermoplastic materials, and production speed due to slow curing times and high void formation during additive manufacturing processes.
Innovation Solution
A composite filament manufacturing method involving impregnating a thread of fibers with a liquid reactive thermoplastic resin and co-extruding a sheath of thermoplastic material around the impregnated thread, allowing for curing of the resin without waiting for full curing, thereby increasing production speed and improving homogeneity and cross-section profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoset resin is used to impregnate the fiber thread, then the composite filament achieves good binding strength, but the curing time becomes long (around 10 minutes) and production speed decreases to 0.3-1 m/min
Solution Approach 1:
The patent changes the chemical parameters of the binder from thermoset resin to thermoplastic resin, which fundamentally alters the curing mechanism from chemical crosslinking (requiring 10 minutes) to physical cooling (immediate), thereby increasing production speed to 10 m/min while maintaining binding strength
Solution Approach 2:
The patent uses a composite binder system combining thermoplastic resin with reactive components, creating a material that exhibits both the binding strength of thermoset resins and the fast processing speed of thermoplastics, resolving the contradiction between strength and productivity
2Strength
If thermoset resin is used as binder, then the composite filament achieves adequate binding, but hot formability is poor and cracks occur during printing when heated
Solution Approach 1:
The patent changes the material parameters from thermoset to thermoplastic resin, which fundamentally improves hot formability by eliminating the crack-prone thermal expansion mismatch between thermoset resin and fiber, while maintaining binding strength through the thermoplastic's viscous flow and cooling solidification
3Ease of manufacture
If thermoset resin is used for impregnation, then the filament can be manufactured, but compatibility with thermoplastic materials is poor and adhesion is weak during 3D printing
Solution Approach 1:
The patent changes the binder chemistry from thermoset to thermoplastic, which improves compatibility with thermoplastic materials by ensuring matching thermal behavior, viscosity characteristics, and adhesion mechanisms, enabling strong interfacial bonding during 3D printing while maintaining ease of manufacture
4Reliability
If thermoset resin is cured at high temperature (up to 400°C), then the resin fully cures, but the process time increases and void formation increases
Solution Approach 1:
The patent changes the curing mechanism from thermal crosslinking (requiring 400°C and 10 minutes) to physical cooling solidification (immediate), achieving complete curing in the same or less time while reducing void formation by eliminating bubble generation during high-temperature curing
Solution Approach 2:
The patent utilizes the phase transition from liquid to solid upon cooling for thermoplastic resin curing, replacing the high-temperature chemical curing process, which eliminates void formation while maintaining curing completeness and reducing time loss
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 results in a composite filament with superior hot formability, enhanced compatibility with a wide range of polymers, and significantly increased production speed, enabling the manufacture of higher-quality products in less time.
Implementation Method 1
impregnating the thread with a liquid reactive thermoplastic resin
Implementation Method 2
co-extruding a sheath of thermoplastic material around the impregnated thread
Implementation Method 3
curing the thermoplastic resin
Data Source
AI summary
A method for manufacturing a composite filament aimed to an additive manufacturing application or a winding application, the method comprising, in the following order: providing a thread of fibers; impregnating the thread with a liquid reactive thermoplastic resin; co-extruding a sheath of thermoplastic material around the impregnated thread; and curing the thermoplastic resin. Additionally, a filament obtained at least partly by the method, the use of the filament for manufacturing a product obtained by an additive manufacturing or by a winding technique, and a machine for performing the method, thereby enabling a high-speed production (e.g., 10 meters per minute) of a filament of high quality.