Amorphous Copolymer Powder for Layer-by-Layer Molding
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Solution Overview
Problem
Current polymer powder-based layer-by-layer manufacturing processes face challenges such as curl distortion, non-uniform volume change due to crystallinity, high viscosity leading to porosity, and the inability to meet diverse material requirements like viscosity, thermal stability, and strength in a single component, limiting the precision and efficiency of rapid prototyping.
Innovation Solution
Development of a thermoplastic random copolymer powder with a melt flow rate (MFR) of 12 g/10 min to 1 g/10 min and a relative solution viscosity of 1.55 to 1.9, specifically a copolyamide with certain monomer units, which allows for selective melting via electromagnetic energy, reducing processing temperature and improving mechanical properties, processability, and reducing shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If semicrystalline thermoplastics are used in layer-by-layer manufacturing, then the material provides good mechanical properties, but curl distortion occurs and volume change is non-uniform due to crystallinity
Solution Approach 1:
The patent changes the material parameter from semicrystalline to amorphous thermoplastic, fundamentally altering the phase behavior and eliminating crystallization-induced distortion while maintaining mechanical properties through controlled viscosity and molecular structure
Solution Approach 2:
The invention exploits the phase transition characteristics of amorphous thermoplastics, which undergo glass transition rather than crystallization, thereby avoiding the non-uniform volume change and curl distortion associated with semicrystalline material phase changes
2Manufacturing precision
If the construction chamber temperature is kept just below the melting point to avoid curl, then curl distortion is reduced, but the cooling period becomes significant and productivity decreases
Solution Approach 1:
The patent changes the material's thermal parameters by selecting amorphous thermoplastics with specific glass transition temperatures and thermal conductivities, enabling faster cooling rates that reduce the cooling period while maintaining dimensional stability
Solution Approach 2:
The invention implements periodic layer deposition and cooling cycles optimized for amorphous materials, where each layer is rapidly cooled before the next is applied, reducing overall cooling time while preventing distortion through controlled thermal history
3Manufacturing precision
If amorphous thermoplastics with high viscosity are used, then curl distortion is reduced, but the material becomes porous due to inability to coalesce properly
Solution Approach 1:
The patent optimizes the viscosity parameter by selecting amorphous thermoplastics with controlled molecular weight and chain structure, achieving a viscosity range that allows proper coalescence and densification while maintaining dimensional stability during processing
Solution Approach 2:
The invention uses composite amorphous thermoplastic formulations combining different polymer components or additives that modify rheological behavior, enabling simultaneous achievement of low distortion and high density through improved melt flow and bonding characteristics
4Device complexity
If a single polymer material is used to meet diverse requirements, then material complexity is reduced, but it is impossible to simultaneously optimize viscosity, thermal stability, and strength
Solution Approach 1:
The patent employs composite thermoplastic materials combining multiple polymer components, fillers, or functional additives in an amorphous matrix, enabling simultaneous optimization of viscosity, thermal stability, and mechanical strength while maintaining a relatively simple single-phase structure suitable for layer-by-layer manufacturing
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 copolymer powder enables faster and more reliable production of moldings with improved mechanical properties, reduced shrinkage, and increased processing latitude, while maintaining sharpness and precision, overcoming the limitations of conventional powders by allowing for tailored properties in a single component.
Implementation Method 1
regions of a powder layer are selectively melted via introduction of electromagnetic energy
Implementation Method 2
regions of a powder layer are selectively melted via introduction of electromagnetic energy
Implementation Method 3
Once the previously molten regions have been cooled and hardened
Data Source
AI summary
The present invention is directed to a process of producing moldings by a layer-by-layer process including selectively melting regions of a respective pulverulent layer via unfocused introduction of electromagnetic energy, using a polymer powder, wherein the powder includes at least one thermoplastic random copolymer with an ISO 1133 MFR value of from 12 to 1 gm/10 min.