Extrusion Head Thermal Shielding for Clean Filament Cutting
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Solution Overview
Problem
Existing additive manufacturing systems face challenges in producing complex shapes with high processing speeds and accuracies, especially when multiple materials are required, and current extrusion heads often deform or fail to cleanly cut extrusion material, leading to inefficiencies and reliability issues under high ambient temperatures.
Innovation Solution
An extrusion head with a convection shield and a blade element design that minimizes air convection, ensures clean cutting of extrusion material, and includes a cooling system to maintain the material in a solid state, combined with a rotatable displacement unit for efficient material handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high nozzle temperatures (up to 440°C) are used for processing high-performance plastics like PEEK, then the material can be properly melted and extruded, but the extrusion material may deform or soften during handling and cutting
Solution Approach 1:
The system is divided into distinct thermal zones: the heating zone (nozzle at 440°C) and the cooling zone (material feed unit with cooling device). This segmentation allows the material to be melted at high temperature in the nozzle while being kept cool and stable in the feed unit, preventing deformation during handling and cutting.
Solution Approach 2:
A cooling device acts as an intermediary between the high-temperature extrusion zone and the ambient environment. This cooling device prevents heat from the nozzle from affecting the material feed unit, thereby maintaining material stability during feeding and cutting operations while allowing high-temperature processing in the nozzle.
2Productivity
If the extrusion material is cut after extrusion, then material handling efficiency is improved, but the material may be deformed or cobweb-like thread formation may occur during cutting
Solution Approach 1:
The material is cooled in advance in the material feed unit before reaching the cutting zone. This preliminary cooling action ensures the material is in a stable, solid state when cutting occurs, preventing deformation and cobweb formation while allowing efficient automated cutting and handling.
Solution Approach 2:
Different thermal conditions are applied to different parts of the system: the nozzle maintains high temperature for melting, while the material feed unit and cutting zone maintain low temperatures for stable handling and clean cutting. This local differentiation of thermal properties enables both efficient processing and high-quality cutting.
3Reliability
If heated air convects to the material feed unit, then the material may soften and become more difficult to process, but preventing convection may require additional shielding components
Solution Approach 1:
A convection shield in the form of a flexible bellows structure is used to prevent heated air from convecting to the material feed unit. This bellows-shaped shield can accommodate thermal expansion and mechanical movements while effectively blocking hot air flow, providing a simple yet effective solution without requiring complex rigid shielding structures.
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 solution enhances process reliability and material handling, preventing deformation and contamination, allowing for precise and efficient processing of materials like PEEK at high temperatures, suitable for aerospace and automotive applications.
Implementation Method 1
a convection shield is provided between the extrusion head and the mounting structure. The convection shield prevents or at least hinders convection of the air.
Implementation Method 2
at least one cooling device is provided for cooling the material feed unit and the displacement unit
Data Source
AI summary
An extrusion head is provided for additive manufacturing of a product, preferably based on the fused filament fabrication method. The extrusion head is arranged within a mounting structure, and a convection shield is provided between the extrusion head and the mounting structure.