3D Printer Composite Filament Nozzle for Void-Free Printing
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Solution Overview
Problem
Current three-dimensional printing methods face limitations in producing durable and strong parts due to weak bonding between deposited materials, air pockets, and voids, as well as difficulties in handling and processing composite materials, particularly with concave shapes and high-friction 'towpregs' that require additional vacuum and heating steps.
Innovation Solution
The use of a continuous core reinforced filament with a multistrand core preimpregnated with a thermoplastic resin, which is void-free and rigid, allowing for improved bonding and reduced voids in printed structures, enabling the deposition of fibers in concave shapes and eliminating the need for subsequent vacuum steps, through a heated conduit nozzle system with a cutting mechanism for precise material control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional Fused Filament Fabrication (FFF) is used to build parts by depositing successive filament beads, then the printing process is simple and direct, but the parts produced are not durable and have weak bonding between deposited materials
Solution Approach 1:
The patent uses composite filament consisting of continuous reinforcement fibers (such as carbon fiber, glass fiber, or aramid fiber) embedded in a thermoplastic matrix material. This composite structure provides both the durability and strength of traditional composite materials and the ease of additive manufacturing, resolving the contradiction between part durability and processing simplicity.
Solution Approach 2:
The patent changes the physical state parameters of the matrix material by heating it to a temperature above its melting point during deposition, allowing the filament to be extruded and bonded. The heating system and controlled cooling process enable the matrix to transition from solid to molten state for bonding, then solidify to create strong interlayer adhesion, improving part durability without requiring additional vacuum or heating steps.
2Reliability
If towpregs including continuous fiber reinforced materials are deposited in a green state and then placed under vacuum and heated, then air voids are removed and parts are fully cured, but the process requires additional vacuum and heating steps
Solution Approach 1:
The patent performs preliminary impregnation of continuous fibers with thermoplastic matrix material before deposition, creating a preimpregnated filament where the matrix is already in close contact with the reinforcement fibers. This preliminary action ensures void-free material structure is achieved during the extrusion process itself, eliminating the need for subsequent vacuum steps and improving printing speed.
Solution Approach 2:
The patent utilizes phase transition of the thermoplastic matrix material from solid to molten state during extrusion through the heated nozzle, and then back to solid state upon deposition. This phase transition allows the matrix to flow and completely impregnate the reinforcement fibers during deposition, creating a void-free structure without requiring additional vacuum or heating steps after printing.
3Strength
If preimpregnated composite construction with sheets of fabric is used, then parts can be made with continuous fiber reinforcement, but the method is not considered three-dimensional printing and requires cutting sheets into two-dimensional patterns
Solution Approach 1:
The patent transitions from two-dimensional sheet-based composite construction to three-dimensional filament-based construction. By extruding continuous fiber-reinforced filament through a heated nozzle, the system enables continuous fiber reinforcement in three-dimensional printed parts while maintaining the simplicity of additive manufacturing processes, eliminating the need to cut sheets into patterns.
Solution Approach 2:
The patent replaces the mechanical cutting and layering process of traditional composite construction with a thermal extrusion process. The heated nozzle melts and extrudes the filament material, allowing continuous fiber reinforcement to be deposited in complex three-dimensional paths without mechanical cutting or manual layering, simplifying the manufacturing process.
4Strength
If filament winding is used to form parts by winding strands of composite around a mandrel, then continuous fiber reinforcement is achieved, but the method is limited to convex shapes due to filaments bridging concave shapes
Solution Approach 1:
The patent employs a dynamic extrusion process where the heated nozzle can precisely control the deposition of filament material in real-time according to complex three-dimensional toolpaths. This dynamic capability allows continuous fiber reinforcement to follow arbitrary paths including concave shapes, overhangs, and complex geometries, unlike static filament winding methods limited to convex shapes.
Solution Approach 2:
The patent changes the physical state of the matrix material to molten phase during extrusion, allowing the material to flow and conform to complex geometries including concave shapes. The heated nozzle and controlled cooling system enable the material to adapt to any desired shape while maintaining continuous fiber reinforcement, overcoming the geometric limitations of filament winding.
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 enhances the strength and speed of three-dimensional printing by reducing voids and the need for additional processing steps, enabling the production of stronger, lighter parts with controlled directional reinforcement and the ability to print complex geometries.
Implementation Method 1
heating the core reinforced filament to a temperature greater than a melting temperature of the matrix material
Implementation Method 2
heating the core reinforced filament to a temperature greater than a melting temperature of the matrix material
Data Source
AI summary
Various embodiments related to three dimensional printers, and reinforced filaments, and their methods of use are described. In one embodiment, a void free reinforced filament is fed into an conduit nozzle. The reinforced filament includes a core, which may be continuous or semi-continuous, and a matrix material surrounding the core. The reinforced filament is heated to a temperature greater than a melting temperature of the matrix material and less than a melting temperature of the core prior to drag the filament from the conduit nozzle.