Pellet-Fed Foamed Polymer 3D Printing for Impact Pads
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Solution Overview
Problem
Existing methods for forming impact absorption pads face challenges in achieving high impact protection while maintaining lightness and flexibility, and are limited by the use of filament-based techniques that restrict material choice and mixing capabilities.
Innovation Solution
A method using immiscible yet compatible polymers, such as thermoplastic elastomers and engineering polymers, is employed in a 3D printing process where the polymers are melted with a foaming agent and extruded to form a foam, allowing for a layered structure with varying properties through controlled foaming and mixing of polymers and agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If foaming techniques or injection moulding techniques are used to form impact absorption pads, then impact protection performance is improved, but the pads become heavier and less flexible
Solution Approach 1:
The patent uses a composite material system comprising a thermoplastic elastomer matrix combined with thermoplastic engineering polymer particles. This composite structure enables the foam to exhibit both flexibility from the elastomer matrix and high energy absorption from the engineering polymer particles, achieving impact protection without excessive weight.
Solution Approach 2:
The patent creates a heterogeneous foam structure where different phases are distributed non-uniformly throughout the material. The thermoplastic engineering polymer particles are dispersed within the thermoplastic elastomer matrix, creating regions of varying density and mechanical properties that optimize both protection and flexibility locally.
2Shape
If filament-based 3D printing techniques are used, then layered structures can be created, but material choice is restricted and mixing capabilities are limited
Solution Approach 1:
The patent employs a granular material feedstock approach where particle size, composition, and distribution can be controlled during printing. By varying the particle size distribution and material composition in the feedstock, the process achieves both layered structure formation and enhanced material versatility compared to filament-based systems.
3Ease of manufacture
If a single polymer is used in the foam, then processing is simplified, but impact protection performance across different energy levels is reduced
Solution Approach 1:
The patent creates a two-phase composite foam system where a thermoplastic elastomer matrix provides flexibility and low-energy impact absorption, while dispersed thermoplastic engineering polymer particles provide high-energy impact protection through controlled collapse. This composite approach maintains relative processing simplicity while achieving multi-level impact protection.
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 enables the creation of impact absorption pads with tailored properties for specific impact scenarios, providing enhanced protection and flexibility by varying polymer ratios and foaming agent use, while offering cost savings and versatility in material selection.
Implementation Method 1
Upon exit from the 3D printing nozzle, the homogenized polymer melt experiences a pressure drop causing the polymer melt to expand and form a foam
Implementation Method 2
the homogenized polymer melt experiences a pressure drop causing the polymer melt to expand and form a foam which is then used to print the protective article
Data Source
AI summary
A method of forming a protective article, comprises feeding pellets (2) of a first and second different and immiscible polymers with a foaming agent to an extruder (4) with a screw (6). The polymers are melted and mixed in the extruder screw (6). The mixture is extruded through a 3D printing nozzle (7) and ejected to create a pressure drop to cause foaming of at least one of the polymers. An article is then printed from the foamed mixture. A 3D printer with two hoppers (1,11) for pellets to feed an extruder (4) with a screw (6).