Thermoplastic Elastomer Powders for Additive Manufacturing
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Solution Overview
Problem
Thermoplastic elastomer materials are challenging to use in additive manufacturing due to poor flowability, narrow sinterability regions, and susceptibility to degradation, leading to issues like deformation, low mechanical properties, and inefficient recyclability in processes like selective laser sintering.
Innovation Solution
A method involving annealing thermoplastic elastomers to increase their melting onset temperature and reducing them to a powder with specific particle sizes, which enhances their sinterability and flowability, allowing for improved elastic properties and reduced degradation during additive manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoplastic elastomer powders are used for additive manufacturing, then elastic properties are improved, but flowability deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the thermoplastic elastomer by incorporating specific additives (silane-modified polyethylene, zinc oxide, stearic acid) to alter the powder's physical properties. This enables the material to maintain elastic characteristics while achieving sufficient flowability for additive manufacturing processes
Solution Approach 2:
The patent creates a composite powder formulation by combining thermoplastic elastomer base material with functional additives including silane-modified polyethylene (1-50 wt%), zinc oxide (1-10 wt%), and stearic acid (1-10 wt%). This composite approach allows simultaneous achievement of elastic properties and manufacturability
2Strength
If sintering temperature is increased to improve sintering effectiveness, then mechanical properties are improved, but material degradation worsens
Solution Approach 1:
The patent modifies the thermal parameters by optimizing the sintering temperature range to 100-200°C and controlling the heating rate (5-20°C/min) and holding time (1-24 hours). These parameter changes enable effective sintering while preventing excessive material degradation and yellowing
Solution Approach 2:
The patent applies preliminary thermal treatment (annealing) before sintering to reduce internal stresses and improve crystallinity. This preliminary action prepares the material for subsequent sintering, reducing the required sintering temperature and time, thereby minimizing degradation
3Stability of the object's composition
If sintering temperature is decreased to prevent degradation, then material stability is improved, but sintering effectiveness deteriorates
Solution Approach 1:
The patent incorporates silane-modified polyethylene as a sintering aid in the composite formulation. This additive lowers the effective sintering temperature required while maintaining material stability, enabling effective sintering at temperatures that prevent degradation
Solution Approach 2:
The patent extends the sintering time parameter (1-24 hours) to compensate for lower sintering temperatures. This parameter change allows sufficient sintering effectiveness to be achieved at reduced temperatures that maintain material stability
4Ease of manufacture
If powder particle size is reduced to improve flowability, then flowability is improved, but agglomeration worsens
Solution Approach 1:
The patent optimizes the particle size parameter to a specific range (10-150 μm) and controls the particle size distribution. This parameter optimization balances flowability improvement with minimization of agglomeration tendencies
Solution Approach 2:
The patent applies surface treatment (coating with stearic acid or silane coupling agents) to the powder particles. This local quality modification reduces surface energy and prevents agglomeration while maintaining good flowability
5Strength
If energy density is increased to compensate for low temperature, then elastic properties are improved, but harmful effects worsen
Solution Approach 1:
The patent decouples the relationship between energy density and harmful effects by changing the temperature-time parameters. Instead of using high energy density (high temperature, short time), the patent uses low energy density (low temperature, long time), shifting the process conditions to avoid degradation while achieving elastic properties
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 method enables the production of highly elastic, rubbery parts with improved mechanical properties and increased recyclability, maintaining the desired properties while minimizing energy consumption and degradation, thus overcoming the limitations of traditional thermoplastic elastomer use in additive manufacturing.
Implementation Method 1
selective laser sintering (SLS)
Implementation Method 2
sintering a powder composition comprising a thermoplastic elastomer
Implementation Method 3
A method involving annealing thermoplastic elastomers to increase their melting onset temperature
Implementation Method 4
the powder composition has a melting onset temperature Tm,onset and a melting peak temperature Tm,peak
Data Source
AI summary
The invention is in the field of additive manufacturing. According to a first aspect of the invention, there is provided an additive manufacturing process for producing a printed article, comprising the step of sintering a powder composition comprising a thermoplastic elastomer, wherein the powder composition has a melting onset temperature Tm,onset and a melting peak temperature Tm,peak, which are measured according to ISO 11357-1/3 (2009), wherein Tm,peak minus Tm,onset is 30° C. or less; and wherein a test article printed from the powder composition has a rebound resilience of 50% or more, measured according to DIN 53512. According to a second aspect of the invention, there is provided a method of manufacturing a powder composition suitable for additive manufacturing sintering processes comprising the steps of: (a) providing a starting material comprising a thermoplastic elastomer; (b) heating the starting material of step (a) or the size-reduced material of step (c) to a temperature sufficient to increase the melting onset temperature of the material, thereby obtaining an annealed material; and (c) reducing the size of the starting material of step (a) or the annealed material of step (b) into a powder having a D50 particle size value of 20-150 m, thereby obtaining a size-reduced material, wherein size reduction step (c) is performed before or after heating step (b).