Experimental Investigation Coupled with Modeling and AI of Binder–Powder Interactions in the Binder Jetting Process: Application to Ceramic Recycling

Context and Challenges

The Binder Jetting additive manufacturing process provides substantial freedom in designing ceramic parts with complex geometries. However, numerous challenges remain regarding the optimization of particle size distribution, binder formulation and its reactivity with powders, as well as post-processing steps such as debinding and sintering. Controlling the stiffness and homogeneity of green parts remains a major challenge.

Physical and chemical interactions between binders and powders lie at the very core of this process. These interactions depend on complex physical and chemical mechanisms: droplet ejection, impact, and capillary penetration—which can induce a local reorganization of the granular packing—as well as chemical interactions between the binders and the grain surfaces, depending on their wettability and viscosity properties.

To address current sustainable development challenges, recycling ceramic products (originating from industrial scrap or end-of-life components) is becoming a central concern for the ceramic industry. Utilizing recycled raw materials requires rethinking process steps, as these materials can exhibit different physical and chemical characteristics compared to virgin raw materials. Binder Jetting is particularly well-suited for incorporating recycled raw materials, provided that optimization work is conducted on the properties of the powders and binders used.

The proposed PhD project will focus on studying binder–powder interactions applied to recycled raw materials. The PhD will be conducted jointly between IRCER and CTTC (Ceramic Technology Transfer Center). This partnership will provide the doctoral candidate with a dual academic and industrial culture, enabling them to conduct fundamental research while addressing the real-world constraints and requirements of an industrial manufacturing environment.

Scientific Approach

The PhD candidate will be at the core of an innovative strategy combining experimentation, modeling, and artificial intelligence:

1. Experimental Part:

Setting up an instrumented test bench (high-speed videography) to analyze impact and wetting dynamics, and to gather data at an intermediate scale between the particle size and the component scale.

Investigating various "powder/binder" pairs to identify the dominant physicochemical interactions.

Manufacturing samples via Binder Jetting, using model powders (such as alumina) and recycled powders (porcelain, etc.), including powder preparation steps.

Characterizing the microstructure and final properties of the green parts: porosity analysis, determination of the binder penetration profile, mechanical properties, and microstructural observations to establish relationships with process parameters.

2. Numerical Modeling and Simulation:

Utilizing an in-house simulation code (Python/GPU) based on the Discrete Element Method (DEM).

Contributing to model development: integrating new physical building blocks derived from experimental observations to refine the prediction of binder propagation "in the core" (a region that is difficult to access via direct measurement).

3. Artificial Intelligence and Knowledge Capitalization:

Implementing a Machine Learning approach to capitalize on all data generated from both real-world experiments and numerical simulations.

The objective is to use AI to identify complex correlations and build a digital twin capable of optimizing process parameters (maximizing mechanical strength, controlling homogeneity).

University of Limoges — A multidisciplinary public university founded in 1968, the University of Limoges hosts over 17,000 students and relies on recognized research across several fields of excellence, notably materials science, the environment, applied mathematics, and healthcare. It also brings together prominent academic institutions, including an IUT (University Institute of Technology) and the ENSIL-ENSCI engineering school.

IRCER — The Institute of Research for Ceramics (IRCER, UMR CNRS 7315) is one of the flagship laboratories of the University of Limoges in the field of materials science. Located at the European Ceramic Center within the ESTER Technopole, it brings together approximately 200 members focused on research in ceramic processing, surface treatments, and high-performance materials, maintaining close ties with the industrial sector.

Education: Master’s degree (MSc) or engineering degree (Grande École), in Materials Science, Physics, Chemistry, Mechanical Engineering, or Process Engineering.

Skills:

- Strong interest in experimental work and physical measurement.

- Keen interest in numerical computation and programming (Python).

- Curiosity about Artificial Intelligence (Data Science).

- Personal Qualities: Scientific rigor, autonomy, and the ability to bridge experimental results with numerical tools.