Fiber-Reinforced 3D Printing With Tensioned Void-Free Deposition
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Solution Overview
Problem
Existing three-dimensional printing techniques fail to effectively integrate the benefits of composite lay-up and filament winding, resulting in parts with reduced strength and durability due to air pockets and weak bonding, and are limited by the inability to deposit composite materials in concave shapes or construct discrete features efficiently.
Innovation Solution
A three-dimensional printer and method that uses a fiber reinforced composite filament with axial fiber strands within a matrix material, heated to melt the matrix interstitially while applying ironing forces to form bonded ranks, maintaining neutral to positive tension, and utilizing a clearance fit channel to prevent buckling, enabling deposition of composite materials in complex shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional three-dimensional printing techniques (FFF or SLA) are used, then parts can be produced with basic structural integrity, but the parts exhibit reduced strength and durability due to air pockets and weak bonding
Solution Approach 1:
The patent applies parameter changes by controlling the thermal state of the matrix material during deposition. The matrix is heated to a temperature above its glass transition temperature (Tg) but below its melting temperature, transforming it from a rigid state to a viscoelastic state that enables intimate bonding between layers while eliminating air pockets. This temperature parameter control resolves the contradiction by ensuring both strong bonding and void-free structure.
Solution Approach 2:
The patent uses composite materials consisting of continuous fiber strands embedded in a matrix material. This composite structure provides both the strength from the fibers and the bonding capability from the matrix, resolving the contradiction between structural integrity and bonding quality. The fiber-matrix composite enables simultaneous achievement of high strength and reliable layer bonding.
2Manufacturing precision
If filament is fed through a tight-fitting conduit nozzle, then deposition precision can be maintained, but the filament buckles due to compression forces
Solution Approach 1:
The patent changes the thermal parameter of the matrix material by heating it above Tg, which transforms its mechanical properties from rigid to viscoelastic. This parameter change reduces the critical buckling load, allowing the filament to remain stable in a clearance-fit conduit without buckling, while still maintaining deposition precision through controlled material flow.
Solution Approach 2:
The heated matrix material acts as an intermediary that mediates between the conflicting requirements of tight fitting (for precision) and buckling prevention. By heating the matrix, it becomes more compliant and can accommodate the clearance-fit geometry without transmitting compressive forces that would cause buckling, thus resolving the contradiction between precision and stability.
3Adaptability or versatility
If composite materials are deposited in concave shapes using conventional techniques, then rotational symmetry can be achieved, but the process is limited to convex shapes due to taut filaments bridging concave areas
Solution Approach 1:
The patent applies parameter changes by controlling the thermal state and tension of the fiber-reinforced filament. By heating the matrix material and maintaining controlled tension during deposition, the filament becomes flexible enough to conform to concave geometries without bridging, enabling the printing of complex non-convex shapes that were previously impossible with conventional techniques.
4Reliability
If vacuum or heating post-processes are applied to eliminate air pockets, then bonding quality can be improved, but the manufacturing process complexity and time increase
Solution Approach 1:
The patent applies preliminary action by ensuring that the matrix material is heated above its glass transition temperature during the deposition process itself, before the part is completed. This preliminary heating action prevents air pocket formation and ensures intimate bonding between layers as the material is deposited, eliminating the need for subsequent vacuum or heating post-processes to achieve bonding quality.
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 achieves void-free composite parts with enhanced strength and durability by maintaining fiber tension and preventing buckling, allowing for the construction of complex shapes and discrete features without the need for vacuum or heating post-processes.
Implementation Method 1
The filament is heated to a temperature greater than a melting temperature of the matrix material to melt the matrix material interstitially within the filament
Implementation Method 2
The unmelted composite filament is fed at a feed rate along a clearance fit zone that prevents buckling of the filament
Implementation Method 3
An ironing force is applied to the melted matrix material and the one or more axial fiber strands of the fiber reinforced composite filament with an ironing lip
Implementation Method 4
the ironing lip is translated adjacent to the part at a printing rate that maintains a neutral to positive tension in the fiber reinforced composite filament between the ironing lip and the part
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Various embodiments relate to a three-dimensional printer (fig. 1a) for the additive manufacturing of a part (14), comprising a fiber composite filament supply of unmelted fiber reinforced composite filament (6) including one or more inelastic axial fiber strands extending within a matrix material of the filament; a movable build platen (16) that supports the part (14); a print head (10) opposing the platen and comprising a heated ironing tip (726) that heats and presses the composite filament such that at least a portion of one or more inelastic axial fiber strands are anchored within the part on the platen; and a plurality of printing actuators that move the print head and the platen relative to one another in at least one degree of freedom.