Pseudo-Amorphous PEEK Extrusion for Additive Manufacturing

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Solution Overview

Problem

The use of semi-crystalline or crystallizable poly-aryl-ether-ketones like PEEK in fused filament fabrication faces challenges such as thermal degradation, nozzle clogging, and uneven crystallization, leading to warpage, dimensional inaccuracies, and unhomogeneous mechanical properties due to high extrusion temperatures and fast crystallization kinetics.

Innovation Solution

An additive manufacturing process using a pseudo-amorphous composition of poly-ether-ketone-ketone with a controlled molar proportion of isophthalic and terephthalic units, extruded at a softening temperature above the glass transition temperature but below 300°C, to avoid warpage and crystallization inhomogeneities, with a viscosity range that allows for stable flow and reduced crystallization kinetics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high extrusion temperature (350-480°C) is used to extrude PEEK, then nozzle clogging and delamination are avoided, but thermal degradation of the polymer occurs

Engineering Contradiction:

Improvenozzle clogging avoidanceVSAvoidthermal degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical composition parameters of the poly-ether-ketone-ketone polymer, specifically controlling the molar proportion of terephthalic units (0-45% or 55-65%) to alter the material's thermal properties and crystallization kinetics, enabling lower extrusion temperatures

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses copolymer compositions combining isophthalic and terephthalic units in specific ratios to create a material with optimized properties that balance flow characteristics at lower temperatures with resistance to thermal degradation

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If build environment temperature is maintained above Tg to avoid residual stress, then stress accumulation is prevented, but fast crystallization kinetics cause warpage and dimensional inaccuracy

Engineering Contradiction:

Improveresidual stress preventionVSAvoiddimensional accuracy

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent changes the crystallization kinetics parameters by controlling the terephthalic unit content in the poly-ether-ketone-ketone, slowing down the crystallization rate to allow controlled crystal growth that prevents warpage while maintaining dimensional accuracy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent pre-modifies the polymer composition to inherently slow crystallization kinetics, providing a buffer against rapid crystallization that would cause warpage, allowing the build environment to maintain temperatures above Tg without suffering from dimensional inaccuracies

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If simple consumer-grade FFF equipment is used, then cost is reduced, but temperature control precision and reliability decrease

Engineering Contradiction:

Improveequipment costVSAvoidtemperature control

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent lowers the required extrusion temperature parameter by modifying the polymer composition, making the process compatible with the limited temperature control capabilities of consumer-grade equipment while maintaining reliable operation

Inventive Principle:

Principle #35Parameter changes

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 approach enables the production of dimensionally stable three-dimensional parts with reduced warping and crystallization issues, avoiding high-temperature degradation and maintaining mechanical properties, while allowing for the use of lower extrusion temperatures to prevent thermal degradation.

Implementation Method 1

softening the composition at a softening temperature above Tg and below 300° C. to form a softened composition which is fluid enough to flow

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 2

extruding the softened composition from the nozzle to form an extruded part section

Methodology Applied

Scientific EffectExtrusion: Extrusion

Implementation Method 3

solidifying the extruded part section

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentUS20240124738A1Additive manufacturing process by extrusion of a poly-ether-ketone-ketone based composition

Publication Date: 2024.04.18 ARKEMA FRANCE SA

AI summary

The invention concerns an additive manufacturing process by extrusion for forming a three-dimensional part with an additive manufacturing machine comprising a nozzle, the process comprising:i) providing a pseudo-amorphous composition having a glass temperature Tg;ii) softening the composition at a softening temperature above Tg and below 300° C. to form a softened composition which is fluid enough to flow and, extruding the softened composition from the nozzle to form an extruded part section; and,iii) solidifying the extruded part section;wherein the composition is based on a homopolymer or a copolymer of poly-ether-ketone-ketone, consisting of: at least an isophthalic (I) repeating unit, having the formula:and, in the case of the copolymer, a terephthalic (T) repeating unit, having the formula:wherein the molar proportion of T units relative to the sum of the T and I units ranges from 0% to 45% or from 55% to 65%.