Polymer-Coated Metal Core Particles for Additive Manufacturing

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Solution Overview

Problem

Conventional powder mixtures for rapid prototyping and manufacturing often experience demixing issues due to differences in density between polymer particles and fillers, leading to inconsistent mechanical properties and handling challenges, which affect the quality and consistency of produced mouldings.

Innovation Solution

The development of composite particles with a core diameter of 1 μm or greater, coated with a polymer that has a melting point achievable by electromagnetic energy, where the ratio of the composite particle diameter to the core particle diameter is 1.15 or greater, providing a firm bond and improved handling characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional powder mixtures of polymer particles and fillers are used, then the process is simple and rapid, but demixing occurs due to density differences leading to inconsistent mechanical properties

Engineering Contradiction:
Improverapid prototyping speedVSAvoidconsistency of mechanical properties
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent combines polymer and filler particles into a single composite particle structure where the filler is embedded within the polymer matrix. This merging eliminates the demixing problem that occurs when separate polymer and filler particles are mixed, as the filler can no longer separate from the polymer during handling and processing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates composite particles with a specific structure where filler particles are incorporated into polymer particles. This composite material approach allows the simultaneous achievement of rapid processing (inherited from the polymer) and consistent mechanical properties (ensured by the uniform distribution of filler within each composite particle).

Inventive Principle:
Principle #40Composite materials

2Strength

If filler particles are mixed with polymer particles, then reinforcement is achieved, but handling becomes difficult due to demixing and inconsistent distribution

Engineering Contradiction:
Improvereinforcement of mouldingsVSAvoidhandling of powder mixture
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent merges filler and polymer into single composite particles, eliminating the handling difficulties associated with separating densities in mixed powders. The composite particles behave as a uniform material during handling, pouring, and layering operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent ensures that each composite particle has a uniform local structure with filler distributed within the polymer matrix. This local uniformity throughout the entire powder batch ensures consistent reinforcement and easy handling, as every particle contributes equally to the final properties.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If polymer coating on core particles is applied with thin coating, then material usage is efficient, but demixing still occurs and mechanical properties vary

Engineering Contradiction:
Improvepolymer material efficiencyVSAvoiduniformity of mechanical properties
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent specifies optimal parameter ranges including a coating thickness ratio (composite particle diameter to core particle diameter) of 1.15 or greater, and core particle diameters of 1 μm or greater. These parameter changes ensure sufficient polymer coating to prevent demixing while maintaining material efficiency and achieving uniform mechanical properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates composite particles with optimized structure where the polymer coating thickness is carefully controlled relative to the core particle size. This composite structure prevents demixing while using polymer efficiently, and ensures consistent mechanical properties through uniform filler distribution within each particle.

Inventive Principle:
Principle #40Composite materials

4Area of stationary object

If core particles with diameter less than 1 μm are used, then surface area is increased, but handling and processing become more difficult

Engineering Contradiction:
Improvesurface area of particlesVSAvoidhandling and processing
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The patent specifies core particle diameters of 1 μm or greater as an optimal parameter range. This parameter change balances the need for sufficient surface area with the practical requirements of handling and processing, avoiding the difficulties associated with ultrafine particles while maintaining adequate surface area for coating and reactivity.

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 solution prevents demixing, ensures consistent mechanical properties, reduces warpage, and enhances recyclability, allowing for uniform components with improved thermal and electrical conductivity, and easier handling and processing.

Implementation Method 1

a melting point of the coating polymer is obtainable when the polymer is exposed to an electromagnetic energy

Methodology Applied
Scientific EffectElectromagnetic radiation heating: Dielectric Heating

Data Source

PatentUS10479733B2Powder comprising polymer-coated core particles comprising metals, metal oxides, metal nitrides or semimetal nitrides
Publication Date: 2019.11.19 EVONIK OPERATIONS GMBH

AI summary

Composite particles comprising core particles completely or partially coated with a precipitated polymer, where the d50 median diameter of the core particles is 1 μm or greater and the ratio of the d50 median diameter of the composite particles to the d50 median diameter of the core particles is 1.15 or greater, are provided. A method to prepare the particles includes dissolution of a polymer in a solvent and reprecipitation of the polymer in the presence of a suspension of the core particles. Further provided is a layer by layer moulding process employing the composite particles and mouldings obtained therefrom.