Water-Based Binder Jetting Additive Manufacturing

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Solution Overview

Problem

Conventional binder jetting processes in additive manufacturing require long cure times for binder solutions, leading to decreased productivity and increased throughput due to the need for extensive curing steps.

Innovation Solution

A water-based binder solution is developed, comprising a thermoplastic binder and a non-aqueous solvent with a boiling point greater than 100 °C, which enables faster vaporization and curing, reducing the overall cure time by increasing the vapor pressure of the binder solution while maintaining suitable viscosity for jetting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional binder solutions are used, then the binder can effectively join powder particles, but the cure time is long which decreases productivity

Engineering Contradiction:
Improvebinder joining effectivenessVSAvoidadditive manufacturing throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the chemical composition parameters of the binder solution by incorporating volatile solvents with specific boiling points (e.g., ethanol, isopropanol, acetone) and adjusting solvent-to-binder ratios. This parameter modification enables faster evaporation rates during curing while maintaining binder effectiveness, thereby reducing cure time from hours to minutes and improving manufacturing throughput without sacrificing part integrity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces volatile solvents as intermediary substances that facilitate faster binder curing. These solvents act as mediators between the binder and the environment, enabling rapid phase change from liquid to vapor that accelerates the curing process. The intermediary solvents allow the binder to set quickly while still providing adequate time for layer deposition and part handling

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If the binder solution viscosity is reduced for faster jetting, then the deposition speed increases, but the binder may not effectively adhere to powder particles

Engineering Contradiction:
Improvebinder jetting speedVSAvoidparticle adhesion effectiveness
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent optimizes the viscosity parameter of the binder solution by carefully selecting solvent types and concentrations. The formulation achieves a viscosity range that permits rapid jetting through the print head while maintaining sufficient adhesion properties. Specific solvent-binder combinations are selected to balance flow characteristics with binding effectiveness, enabling high-speed deposition without compromising particle adherence

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite binder solution system combining multiple components: binder polymers, volatile solvents, and potentially surfactants or additives. This composite formulation synergistically combines the low-viscosity benefits of solvents with the adhesion properties of binders, achieving both fast jetting speed and reliable particle attachment in a single optimized solution

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If a water-based binder solution is used, then the environmental safety improves, but the curing time increases due to water's high boiling point

Engineering Contradiction:
Improveenvironmental safetyVSAvoidcure time
Core Design Contradiction:
Object-affected harmful factorsVSDuration of action of moving object

Solution Approach 1:

The patent segments the curing process into two distinct phases: first, rapid evaporation of volatile solvents (ethanol, isopropanol, acetone) that occurs within minutes at ambient or slightly elevated temperatures; second, slower evaporation of water that occurs subsequently. This segmentation allows the majority of curing to be completed quickly by the volatile components, dramatically reducing the perceived cure time while maintaining the environmental benefits of water-based formulation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces volatile solvents as intermediary substances that accelerate the initial curing phase. These intermediaries perform the rapid evaporation function first, providing quick initial set and strength, while the water component continues to evaporate more slowly afterward. The intermediary volatiles bridge the gap between environmental safety requirements and fast curing needs

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 water-based binder solution significantly reduces the curing time, enhancing the throughput of additive manufacturing processes without compromising the integrity of the green body part, allowing for faster layer-by-layer drying and improved handling during post-printing processes.

Implementation Method 1

enabling faster vaporization of the solvent and, therefore, curing

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 2

reducing the overall cure time by increasing the vapor pressure of the binder solution

Methodology Applied
Scientific EffectVapor pressure: Vapour Pressure

Implementation Method 3

non-covalently coupling the first and second polymer strands together via interaction between the first and second functional groups

Methodology Applied
Scientific EffectNon-covalent coupling:

Data Source

PatentEP3915697B1Water-based binders and methods of use in additive manufacture of parts
Publication Date: 2023.12.13 GENERAL ELECTRIC CO
  • EP3915697B1 patent drawingFigure 1
  • EP3915697B1 patent drawingFigure 2

AI summary

A method of manufacturing comprises depositing a layer of a powder (202) on a working surface (204) and selectively depositing a water-based binder solution (206) comprising from 0.1 wt% to 5 wt% of a non-aqueous solvent having a boiling point of greater than 100 °C and less than or equal to 175 °C at 1 atm and a thermoplastic binder (216) comprises a first polymer strand (220) including a first functional group and a second polymer strand (222) including a second functional group into the layer of powder (202) in a pattern representative of a structure of a part. The method further comprises non-covalently coupling the first and second polymer strands (220, 222) together via interaction between the first and second functional groups to form a green body part.