Interfacially Modified Particulate Materials for Metal Injection Molding

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Solution Overview

Problem

The existing powder injection molding and 3D printing processes face challenges with the lack of viscoelastic properties and efficient particle packing in metal injection molding (MIM) and 3D printing, leading to defects such as low strength, density, and excessive energy requirements due to the materials' poor flow characteristics and packing fractions.

Innovation Solution

The use of interfacially modified particulate materials, where ceramic or metal particles are coated with an interfacial modifier and combined with a thermoplastic polymer, enhancing particle packing fractions and viscoelastic properties, allowing for improved extrusion, injection molding, and 3D printing processes with reduced shrinkage and increased strength and density of the final products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional inorganic or metal powders are used in injection molding and 3D printing processes, then the basic forming capability is achieved, but the materials lack viscoelastic properties and efficient particle packing, leading to poor flow characteristics and low product quality

Engineering Contradiction:
Improveproduct qualityVSAvoidflow characteristics
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

An interfacial modifier is introduced as an intermediary substance between the inorganic/metal particles and the polymer matrix. This modifier coating on particle surfaces improves interfacial adhesion and enables the composite material to exhibit viscoelastic properties, thereby resolving the contradiction between product quality and flow characteristics during injection molding and 3D printing processes

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite material system consisting of inorganic/metal particles, polymer matrix, and interfacial modifier. This composite structure combines the benefits of rigid particles with the viscoelastic properties of the polymer-modifier system, enabling both high product quality and good flow characteristics that neither component could achieve alone

Inventive Principle:
Principle #40Composite materials

2Strength

If conventional particle packing methods are used, then the forming process can proceed, but insufficient particle packing results in low density and strength in the final products

Engineering Contradiction:
Improveproduct strengthVSAvoidparticle packing density
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The interfacial modifier acts as a mediator that improves particle-polymer adhesion and facilitates more efficient particle packing during the forming process. This enhanced packing density directly contributes to higher product strength and better manufacturing precision

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The interfacial modifier changes the surface properties of particles, modifying parameters such as surface energy and wettability. These parameter changes enable particles to pack more efficiently and achieve higher density in the final product, thereby improving both strength and manufacturing precision

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional materials are used in injection molding and 3D printing, then the basic processing can be completed, but excessive energy is required due to poor flow characteristics and inefficient particle packing

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The interfacial modifier serves as a lubricating intermediary between particles and the polymer matrix, reducing internal friction and improving flow characteristics. This reduction in resistance to flow decreases the energy required for injection molding and 3D printing processes, thereby improving productivity while lowering energy consumption

Inventive Principle:
Principle #24Intermediary (Mediator)

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 interfacially modified particulate materials enable higher packing densities and improved mechanical properties, such as tensile strength and impact resistance, while reducing process pressures and energy requirements, resulting in more reproducible and high-quality final products.

Implementation Method 1

surface modified particulate and polymer composite material... interfacially modified particulate, where ceramic or metal particles are coated with an interfacial modifier

Methodology Applied
Scientific EffectSurface modification: Coatings

Implementation Method 2

combined with a thermoplastic polymer, enhancing particle packing fractions and viscoelastic properties, allowing for improved extrusion, injection molding

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 3

sintered during the hot compaction stage or after the cold compaction stage to obtain a shaped inorganic or metal object in which the bonds between individual particles form

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentUS11000895B2Surface modified particulate and sintered or injection molded products
Publication Date: 2021.05.11 TUNDRA COMPOSITES LLC

AI summary

Disclosed are interfacially modified particulate and polymer composite material for use in injection molding processes, such as metal injection molding and additive process such as 3D printing. The composite material is uniquely adapted for powder metallurgy processes. Improved products are provided under process conditions through surface modified powders that are produced by extrusion, injection molding, additive processes such as 3D printing, Press and Sinter, or rapid prototyping.