Photocurable Ceramic Formulation Sedimentation Control

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Solution Overview

Problem

Existing photocurable formulations for additive manufacturing are prone to sedimentation of ceramic components, especially with micron-sized particles, leading to stability issues and difficulties in re-dispersion, which complicates their use in additive manufacturing processes, particularly for metal casting applications.

Innovation Solution

A method involving the mixing of a ceramic dispersion with a D50 value of at least 2 µm, a first acrylate, and a dispersant with a solution containing a second acrylate and a photoinitiator to create a photocurable formulation that is stable against sedimentation and suitable for additive manufacturing, using common mixing devices for simplicity and cost-effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If highly filled ceramic formulations are used to achieve high ceramic content, then productivity and manufacturing efficiency are improved, but sedimentation occurs leading to stability deterioration

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidformulation stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameters of the formulation by introducing a dual-acrylate system (first and second acrylates with different functionalities) and optimizing the photoinitiator concentration. This chemical parameter modification allows the formulation to maintain high ceramic content (70-90 wt%) while preventing sedimentation through improved molecular interactions and viscosity characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite photopolymerizable binder system combining two different acrylates (e.g., monofunctional and polyfunctional acrylates) with ceramic particles and photoinitiator. This composite approach provides both the necessary viscosity for suspension stability and the reactivity for complete curing, resolving the contradiction between high filling and stability.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If micron-sized ceramic particles are used to enable metal casting processes, then adaptability to metal casting applications is improved, but sedimentation increases making re-dispersion difficult

Engineering Contradiction:
Improvemetal casting application suitabilityVSAvoidsedimentation
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a photoinitiator as a chemical intermediary that enables complete polymerization of the binder system. This complete curing creates a robust matrix that firmly holds micron-sized ceramic particles (D50 ≥ 2 µm), preventing sedimentation during storage and handling while maintaining the adaptability for metal casting applications.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes the particle size parameter by specifying D50 ≥ 2 µm for ceramic particles, which balances the requirements for metal casting applicability with improved suspension stability compared to smaller particles. This parameter change enables the use of larger particles without excessive sedimentation.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If simple mixing devices are used to reduce complexity and cost, then ease of manufacture is improved, but mixing homogeneity may be compromised

Engineering Contradiction:
Improveprocess simplicityVSAvoidformulation homogeneity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent modifies the viscosity parameters of the photopolymerizable binder through careful selection of acrylate ratios and molecular weights. This viscosity optimization ensures that even simple mixing devices can achieve adequate homogeneity, while the formulation remains stable against sedimentation. The binder viscosity is tuned to provide both ease of mixing and suspension stability.

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

The resulting photocurable formulation maintains low viscosity, preventing sedimentation for at least 12 hours, enabling high-precision and mechanically stable three-dimensional parts, and can be stored for 12 weeks without degradation, facilitating easy removal from molds and further processing.

Implementation Method 1

The polymerization of said monomers is induced by means of the UV radiation

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3464214B1Production of a photocurable formulation for additive manufacturing
Publication Date: 2021.02.17 BASF SE
  • EP3464214B1 patent drawingFigure 1

AI summary

The present invention relates to a method for the production of a photocurable formulation (F) for the use in an additive manufacturing process. In this method a ceramic dispersion (CD) comprising at least one ceramic material, at least one first acrylate and at least one dispersant is mixed with a solution (S) which comprises at least one second acrylate and at least one photoinitiator to obtain the photocurable formulation (F). The present invention furthermore relates to the photocurable formulation (F) obtainable by the inventive method and to a method for the production of a molding in an additive manufacturing process by curing the photocurable formulation (F). Moreover, the present invention relates to the use of the photocurable formulation (F) in an additive manufacturing process.