3D Printed Polymer Components Using Dual-Melting Point Powder Sintering
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Solution Overview
Problem
Additive manufacturing processes, such as laser sintering, often result in components with brittle mechanical properties due to the formation of crystalline structures and residual porosity, leading to inadequate strength and toughness, especially with polymers like PA12 and PP, which lose their typical characteristics.
Innovation Solution
A method involving the deposition of at least two powdery components with different melting points, where the component with the lower melting point is melted and partially melted together within a temperature range specific to the higher melting point, followed by cooling and removal of unmelted components, using materials like PEEK, polyamides, and inorganic salts to achieve high stability and homogeneous mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser sintering is used to manufacture PA12 components, then the components can be produced by additive manufacturing, but the mechanical properties become brittle with elongation at break around 15% instead of >200%
Solution Approach 1:
The invention changes the thermal processing parameters by using a two-stage temperature approach: first heating to above the melting point of the sacrificial powder to enable melting and flow, then cooling to below the melting point to solidify. This parameter change allows the polymer to form dense, crack-free structures with improved mechanical properties while maintaining additive manufacturing capability
Solution Approach 2:
The invention introduces a sacrificial powder component as an intermediary material that melts during processing to enable polymer coalescence. The sacrificial powder acts as a temporary support structure that facilitates dense packing of polymer particles, then is removed after serving its purpose. This intermediary enables the transition from porous green body to dense final part with improved mechanics
2Productivity
If conventional sintering processes are used, then components can be manufactured, but long-term temperature exposure causes degradation and poor mechanical properties
Solution Approach 1:
The invention uses periodic thermal action with distinct heating and cooling phases. The rapid heating to melting point followed by rapid cooling creates a short-duration thermal cycle that achieves sintering without prolonged temperature exposure. This periodic thermal treatment prevents polymer degradation while ensuring complete melting and densification
Solution Approach 2:
The invention rushes through the critical temperature zone by rapidly heating to and then quickly cooling from the melting point. This minimizes the time the polymer spends at temperatures where degradation could occur, while still achieving complete melting and densification. The process skips the prolonged dwell time characteristic of conventional sintering
3Adaptability or versatility
If thermoplastic elastomers are used in laser sintering, then elastic properties can be achieved, but high residual porosity results and strength does not correlate with initial material strength
Solution Approach 1:
The invention changes the processing temperature parameter to above the melting point of the sacrificial powder, enabling complete melting and flow that eliminates residual porosity. This temperature parameter change allows TPE materials to achieve full densification while maintaining their elastic properties, creating a correlation between initial material strength and final component strength
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 method produces components with improved mechanical properties, including increased hardness and tear strength, while avoiding the disadvantages of long-term temperature exposure in common sintering processes, and allows for the processing of a wide range of thermoplastic polymers with high material yield and cost-effectiveness.
Implementation Method 1
Heat-treating the powder layer to a temperature above the melting point of the component with the lowest melting point and below the melting point of the component with the highest melting point, wherein the powder components of the component with the lower melting point are melted and at least partially melted together
Implementation Method 2
Cooling the heat-treated powder layer from step b) to a temperature below the melting point of the lowest-melting component
Data Source
Figure 1
AI summary
The invention relates to a method for producing an object from different powdered components by means of additive manufacturing, wherein a plurality of powdered components having different melting points are simultaneously placed in precise positions, and the powder coating (1) is subsequently thermally treated. The construction material is, for example, polyether ether ketone (PEEK), polyaryl ether ketone (PAEK), polyether ketone ketone (PEKK), polyether sulfone, polyimide, polyether imide, polyester, polyamides, polycarbonates, polyurethanes, polyvinyl chloride, polyoxymethylene, polyvinyl acetate, polyacrylates, polymethacrylates, polyethylene, polypropylene, polylactide, ABS (acrylonitrile butadiene styrene copolymers), PETG (glycol modified polyethylene terephthalate), polystyrene, or mixtures thereof. The supporting material is an inorganic salt of the alkali metals, an inorganic salt of the alkaline earth metals, or a mixture thereof.