FFF Print Head Cooling Layout for Filament Stiffness Control
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Solution Overview
Problem
Fused filament fabrication (FFF) systems face issues with subpar mechanical properties due to imperfect weld lines and inter-laminar bonding, leading to premature failure and compromised geometric accuracy, and existing solutions are complex, expensive, or time-consuming.
Innovation Solution
A fused filament fabrication print head system with a heating block and a cooling element spaced apart along the filament flow path provides localized cooling to preserve filament stiffness and ensure sufficient back pressure, enhancing mechanical properties without additional complexity or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If post-process thermal annealing is applied to increase inter-laminar bonding, then mechanical strength is improved, but geometric accuracy is compromised and build time increases
Solution Approach 1:
The patent applies thermal annealing during the printing process itself rather than as a post-process step. The heating block is positioned to anneal layers immediately after deposition while the part is still on the build platform, achieving improved inter-laminar bonding without requiring separate post-processing operations
Solution Approach 2:
The heating block operates continuously during the printing process, maintaining optimal temperature zones as layers are deposited. This continuous thermal treatment ensures consistent inter-laminar bonding throughout the build without interrupting the printing workflow or requiring additional time
2Strength
If external heating sources like microwave or laser are used to facilitate inter-laminar bonding, then mechanical properties are improved, but device complexity and cost increase
Solution Approach 1:
The heating block leverages the existing thermal field generated by the FFF process itself. The heated nozzle and deposited material create a natural thermal zone that the heating block enhances, eliminating the need for external microwave or laser heating systems
Solution Approach 2:
The heating block is integrated into the build platform structure, combining the functions of platform heating and layer annealing in a single component. This merging of functions simplifies the overall system architecture compared to adding separate external heating devices
3Ease of operation
If filament is heated above glass transition temperature for deposition, then material flow is improved, but filament stiffness is reduced affecting back pressure
Solution Approach 1:
The heating block creates a localized thermal zone specifically at the deposition point where high temperature is needed for material flow. The build platform below this zone remains at lower temperature, maintaining filament stiffness and back pressure in the feed path while enabling proper material extrusion at the nozzle
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 system improves the mechanical strength and toughness of printed parts by maintaining filament integrity and ensuring effective bonding between layers, while maintaining geometric accuracy and reducing print time.
Implementation Method 1
a cooling element spaced apart from the heating block along the filament flow path, the cooling element being configured to provide localized cooling to a portion of the filament at a location along the filament flow path prior to the heating block
Implementation Method 2
a heating block coupled to the nozzle such that the filament flow path extends through the heating block, the heating block including a heating element
Implementation Method 3
a thermoplastic filament is heated above its glass transition temperature to form a polymer melt which is dispensed through a heated liquefier onto a heated build platform
Data Source
AI summary
Various implementations include a fused filament fabrication print head system that includes a nozzle, a heating block, and a cooling element. The nozzle defines a nozzle opening and a filament flow path and is configured to deposit a filament through the nozzle opening. The heating block is coupled to the nozzle such that the filament flow path extends through the heating block. The heating block includes a heating element. The cooling element is spaced apart from the heating block along the filament flow path and is configured to provide localized cooling to a portion of the filament at a location along the filament flow path prior to the heating block. The localized cooling provided by the cooling element preserves the stiffness of the filament and ensures sufficient back pressure to push the filament through the heating block and nozzle opening.