Amorphous Polymer Crystallization for Powder Bed Fusion Resolution
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Solution Overview
Problem
Amorphous polymer powders, such as polycarbonates and polyetherimides, are challenging to use in powder bed fusion processes due to their gradual melting range, leading to unstable processing and poor feature resolution in three-dimensional articles, despite offering low shrinkage properties.
Innovation Solution
Converting amorphous polymers into at least partially crystalline polymeric powders through solvent-induced, vapor-induced, or nucleating agent-induced crystallization, which allows for sharp melting points and improved processing, resulting in articles with excellent dimensional control and reduced warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If amorphous polymer powders are used in powder bed fusion processes, then low shrinkage properties are achieved, but thermal energy dissipates into surrounding regions causing poor feature resolution
Solution Approach 1:
The patent changes the physical state parameter of the polymer from amorphous to crystalline. Crystalline polymers have a sharp melting point compared to the gradual melting range of amorphous polymers, which concentrates thermal energy at a specific temperature threshold and reduces dissipation into surrounding regions, thereby improving feature resolution
Solution Approach 2:
The patent creates a composite approach by combining crystalline polymer powder with specific particle size distributions and morphologies. The crystalline structure provides sharp melting behavior while the particle characteristics optimize energy absorption and transfer, resolving the contradiction between energy concentration and material properties
2Reliability
If amorphous polymer powders are used in powder bed fusion processes, then low shrinkage properties are maintained, but processing stability deteriorates
Solution Approach 1:
The patent transforms the thermal response parameter from gradual (amorphous) to sharp (crystalline). The sharp melting point of crystalline polymers creates a more predictable and controllable processing window, improving both processing stability and dimensional control by eliminating the gradual softening behavior that causes variability
3Manufacturing precision
If amorphous polymers are converted to crystalline form, then sharp melting points are achieved, but processing complexity increases
Solution Approach 1:
The patent performs crystallization as a preliminary action before the powder bed fusion process. By pre-converting amorphous polymer powder to crystalline form through solvent-induced or vapor-induced crystallization, the material is prepared in advance with the desired sharp melting characteristics, eliminating the need for complex real-time control during fusion
Solution Approach 2:
The patent uses solvent or vapor as an intermediary to induce crystallization. These intermediaries facilitate the phase transition from amorphous to crystalline state through controlled exposure, providing a simple and effective method to achieve sharp melting points without complex equipment
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 crystalline powders exhibit sharp melting behavior, reducing melting energy and shrinkage, leading to improved feature resolution and reduced warpage in the final three-dimensional articles, while maintaining the low shrinkage benefits of amorphous polymers.
Implementation Method 1
converting a first amorphous polymer to an at least partially crystalline polymeric powder composition... wherein the crystallization converting step comprises solvent induced crystallization, vapor induced crystallization or plasticizer or nucleating agent induced crystallization
Implementation Method 2
powder bed fusing the at least partially crystalline polymer powder composition to form a three-dimensional article... in which thermal energy selectively fuses regions of a powder bed
Data Source
AI summary
A method of making an article, the method comprising converting a first amorphous polymer to an at least partially crystalline polymeric powder composition and powder bed fusing the at least partially crystalline polymer powder composition to form a three-dimensional article comprising a second amorphous polymer.