Filament Shaping for Additive Manufacturing
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Solution Overview
Problem
Existing additive manufacturing processes using thermoplastic fiber composites face issues with fiber wetting, breakage, and surface finish due to complete melting and twisting of fibers, leading to compromised mechanical properties and surface quality.
Innovation Solution
A method involving the use of a laser to soften and partially melt fiber composite filaments, followed by flattening with a roller to increase the aspect ratio, allowing for improved fiber adhesion and bonding without complete resin flow, enabling the creation of parts with enhanced mechanical properties and surface fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic composite filament is completely melted and deposited through a heated nozzle, then the deposition process is simplified and continuous, but fiber wetting is reduced and fiber breakage occurs due to twisting and tangling
Solution Approach 1:
The patent changes the thermal processing parameters by using localized heating (laser) to soften only the specific region where the filament contacts the build surface, rather than completely melting the entire filament. This partial softening maintains fiber integrity while enabling adequate wetting and adhesion during deposition.
Solution Approach 2:
The laser pre-heats and softens the filament at the deposition point before the filament fully contacts the build surface. This preliminary softening action prepares the resin matrix for bonding without requiring complete melting, thereby preventing fiber tangling and breakage while ensuring proper wetting.
2Ease of manufacture
If thermoplastic composite filament is completely melted, then deposition is facilitated, but fiber breakage and surface finish quality deteriorate
Solution Approach 1:
The patent controls the thermal processing parameter by applying localized laser heating that softens the filament sufficiently for deposition while avoiding complete melting. This precise temperature control prevents fiber breakage and maintains smooth surface finish by eliminating the twisting and tangling that occurs with complete melting.
3Reliability
If thermoset resin is used to ensure high fiber wetting, then fiber adhesion is improved, but operating temperature resistance is reduced
Solution Approach 1:
The patent changes the processing temperature parameter by using localized laser heating to achieve sufficient resin softening for wetting without reaching the temperatures required for complete melting. This allows thermoplastic resins to exhibit wetting characteristics similar to thermosets while maintaining their superior high-temperature resistance and mechanical properties.
4Ease of manufacture
If nozzle pressure is increased to force polymer underneath fiber tow, then deposition completeness is improved, but fiber adhesion loss and wetting reduction occur
Solution Approach 1:
The patent replaces the mechanical pressure system (nozzle pressure) with a thermal system (laser heating). Instead of forcing polymer underneath fiber tow through mechanical pressure, the laser softens the resin matrix thermally, allowing it to flow and wet the fibers naturally without requiring high pressure, thereby maintaining fiber adhesion.
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 process enhances inter-laminar strength, prevents fiber breakage, and allows for the production of parts with complex geometries and improved surface finish by maintaining fiber adhesion and reducing void spaces, resulting in parts with superior mechanical properties and surface quality compared to traditional methods.
Implementation Method 1
heating, with a laser, at least a portion of a second fiber composite filament
Implementation Method 2
heating, with a laser, at least a portion of a second fiber composite filament; the reinforced filament is heated to a temperature greater than a melting temperature of the matrix material
Implementation Method 3
flattening the first composite filament with a roller; a filament shaper comprising a roller, wherein the filament shaper applies pressure to the fiber composite filament, reshaping same
Implementation Method 4
The strength of a fiber composite is determined by the wettability of the fiber within the resin matrix. Wettability refers to the degree of adhesion and bonding between the resin and the fibers.
Data Source
Figure 1A~1D
Figure 2
Figure 3
AI summary
A method and apparatus for additive manufacturing wherein a fiber composite filament having an arbitrarily shaped cross section is softened and then flattened to tape-like form factor for incorporation into a part that is being additively manufactured.