PEEK/PEDEK Copolymer Particles for ALM
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Solution Overview
Problem
Components made by Additive Layer Manufacturing (ALM) using PAEK polymer particles typically have lower strength and higher porosity compared to those made by injection molding, and PAEKs with higher mechanical strength have high melting points, making them difficult to use in ALM by selective laser sintering.
Innovation Solution
A PEEK/PEDEK copolymer with a specific molar ratio of EEK to EDEK repeat units and a narrow melt viscosity range is used, resulting in particles that exhibit improved tensile toughness, tensile strength, and elongation at break, with a lower melting point and higher bulk density for efficient melt-bonding and reduced porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PAEK polymers with higher mechanical strength are used, then tensile strength and elongation at break are improved, but melting point increases making them difficult to use in ALM by selective laser sintering
Solution Approach 1:
The patent modifies the chemical composition parameters of PAEK polymers by introducing specific copolymer structures (PEEK/PEDEK with defined molar ratios) and controlling molecular weight distribution, thereby changing the material's thermal and mechanical properties to achieve both high strength and lower melting point
Solution Approach 2:
The patent creates composite polymeric materials by combining different PAEK polymer types (PEEK and PEDEK) in specific molar ratios, resulting in a material that exhibits superior mechanical properties while maintaining processability at lower temperatures for ALM
2Ease of manufacture
If conventional PAEK polymer particles are used in ALM, then manufacturing is feasible, but components have lower strength and higher porosity compared to injection molding
Solution Approach 1:
The patent optimizes particle morphology parameters (sphericity, size distribution) and material parameters (melt viscosity, crystallinity) to enable ALM processing while producing components with density and mechanical properties approaching those of injection-molded parts
Solution Approach 2:
The patent creates particles with non-uniform internal structure (core-shell morphology) where the core and shell have different crystallinity and density, allowing optimized local properties for both processing and final component performance
3Strength
If PAEK polymer particles with high mechanical strength are used, then component strength is improved, but porosity increases
Solution Approach 1:
The patent controls polymer crystallinity and melting characteristics through compositional parameters to achieve dense particle packing and reduced porosity while maintaining high mechanical strength through optimized molecular structure
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 PEEK/PEDEK copolymer particles achieve improved mechanical properties and reduced porosity in components formed by ALM, with enhanced tensile strength and elongation at break, while maintaining a lower melting point for easier processing.
Implementation Method 1
the uppermost layer of powder selectively sintered, for instance by selective heating with a laser, in order to melt-bond powder particles together
Implementation Method 2
selective heating with a laser
Implementation Method 3
melt-bond powder particles together, and to melt bond them to the layer on which they are deposited
Data Source
AI summary
A polyaryletherketone, PAEK, in the form of particles is a copolymer with at least 95 mole % repeat units of formula I, and repeat units of formula II, and a molar ratio I:II from 55:45 to 80:20. The PAEK has a melt viscosity, MV, from 0.35 to 0.55 kNsm−2 at 1000 s−1. The PAEK is of use in formation of components having high elongation at break when formed by selective sintering and melt-bonding of sequentially deposited layers of powder comprising the PAEK particles. Also provided are processes for making the PAEK particles, powders including them and their use and methods of their use in component formation.