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FR18_Material Processes Interaction_Robin Kromer

Robin Kromer


Group description

The research areas of I2M Material Processes Interaction (MPI) department focus on processes of implementing, shaping and assembling materials, highlighting interactions between the process and the material.

The objective is to understand the physical and physico-chemical mechanisms involved in manufacturing processes using approaches that are both experimental and numerical supplemented by the physico-chemical and mechanical characterisation of the materials produced. A multi-disciplinary system is essential, where all phenomena and their combinations are studied using a multiscale approach.

Our complementary skills (materials, processes, implementation) are an undeniable asset in the Department because the most of applications are meeting current to industrial challenges.

The activities of the three Groups are as follows :

GT1 - Material Implementation Processes works in modelling couplings, especially between heat transfers and mass transfers, metallurgical (or chemical) states and mechanical states for manufacturing additive processes (SLM), processes for preparing metal matrix composites (MMC by liquid and solid route, winding process), composite recycling and welding (TIG, laser and FSW).

GT2 - Material removal processes works about problems associated with understanding and modelling the mechanisms involved in removing material with a cutting tool, applied to monolithic materials or multi-materials.

GT3 - Mechanics of Compacted Pharmaceutical Powders works on issues related to pharmaceutical powders and their transformation by compression via different individual stages in pharmaceutical process engineering.

The GT1 is based on studying interactions between a material (metal or organic) and a process. The processes we study are initiated by thermal phenomena (welding by material fusion or producing composite materials via liquids, additive manufacturing by SLM) and/or mechanical phenomena (friction stir welding or producing composite materials via solids, winding process).

In the course of our work, we have developed models to help understand interaction mechanisms, modelled microstructural changes, developed predictive models and numerical simulation of the processes, and dealt with problems in an industrial context.

The activities of the group focus on understanding the physical phenomena inherent in processes and the pairing of these phenomena, in order to correlate the

operating parameters of the process, microstructures and characteristics. We are interested in modelling couplings, especially between heat transfers (with liquid/solid changes of state) and mass transfers (diffusion phenomena), metallurgical states (segregations, metallurgical transformations, resin polymerisation) and mechanical states (residual stresses, preform deformation).

The processes for manufacturing MMC and the winding process generate phenomena combined with mass transfers (moving liquid metal, diffusion of material), heat and deformations of the preform on different scales.

In the case of welding processes, the metallurgical transformations (or chemical) and microstructural evolutions depend on thermal evolutions and mechanical phenomena.

The quality of the parts produced by the SLM additive manufacturing process depends on several factors: laser-material interactions, porosity rate, interstitial contamination, operating parameters, powder quality, ...


  • Laser
  • Powder/Wire
  • Melting
  • Metallic
  • Modeling
  • Heat
  • Data
  • Monitoring
  • Sensors
  • Machine Learning

Team Description

  • KROMER Robin (Personal Investigator)

  • ARVIEU Corinne (Co-Principal Investigator)

  • LACOSTE Eric (Co-Principal Investigator)



    Pl: KROMER

    Funding Agency*: National

    Ongoing: yes

  • BLUE


    Funding Agency*: Regional

    Ongoing: yes



    Funding Agency*: European

    Ongoing: no

* INT - International EU - European NAT - National RE - Regional


  • R.KROMER, C.GORNY, E.GRUHIER, C.ARVIEU, E.LACOSTE, = Absorptivity measurement of solid and powder bed under IR laser beam, Optics and Laser Technology, 2022

  • C.ARVIEU, C.GALY, E.LEGUEN, E.LACOSTE Relative Density of SLM-Produced Aluminum Alloy Parts: Interpretation of Results Manufacturing and Materials Processing 2020, = Relative Density of SLM-Produced Aluminum Alloy Parts: Interpretation of Results, Manufacturing and Materials Processing, 2020

  • P.YADAV, O.RIGO, C.ARVIEU, E.LEGUEN, E.LACOSTE, = Data Treatment of In Situ Monitoring Systems in Selective Laser Melting Machines, Advanced Engineering Materials, 2021

  • D.COMBERTON, RKROMER, E.LACOSTE, = Analysis of Data from In-Situ Monitoring of Additive Manufacturing Process, Advances on Mechanics, Design Engineering and Manufacturing, 2022

  • P. YADAV, O. RIGO, C. ARVIEU, E. LACOSTE, = Microstructural and Mechanical aspects of International Journal of Advanced 2022 AlSi7Mg0.6 Alloy related to Scanning Strategies in L-PBF, International Journal of Advanced Manufacturing Technology, 2022

Research Lines


Methodology for integrating in-situ analysis data into digital thermal models for the generation of a digital twin of metal additive manufacturing processes

Additive manufacturing processes for metallic materials are experiencing considerable growth in many industrial sectors. Mastering the final characteristics of parts and their microstructure remains a crucial issue today for these processes, in particular for the LBM and WAAM processes. To achieve this objective, research is turning to real-time in-situ data acquisition in order to develop predictive tools to assess deviations during manufacturing. The objective is on the one hand to acquire relevant in-situ analysis data of the metal additive manufacturing process from an instrumented bench representative of the additive manufacturing process. These data will then be processed and used to set up representative patterns of capitalizable information. In a second step, based on the meta-models developed, the work will focus on the coupling of data to a numerical model for the optimization of the digital twin. The objective is to be able to generate thermal simulations (even thermomechanical) allowing to have a simulation tool at the scale of the part taking into account the characteristics at the fine scales. This step will be based on recognition methodologies (pattern recognition). A global methodology will be proposed justifying the classification tools, the awareness of the models and the choice of the data necessary for feeding the calculation codes.

In-situ Monitoring / Analysis / Control

Absorptivity can then reach 80% with the materials considered in LPBF AM technology using lasers in blue or green wavelengths for example. The problem proposed is to be able to evaluate the levels of interactions with different lasers in order to predict and/or investigate the microstructures and defects depending on the material. For this, we propose on the one hand, to quantify in situ the quantity the deposition energy deposition which is released during the laser-metal interaction (vapor, poder, meltpool), and on the other hand, to analyze in-situ the real volumetric energy density for different process parameters (but also laser wavelength). All of the information will be correlated with the microstructures obtained and will make it possible to optimize the operating parameters to answer many questions linked to the interactions between the laser and material: for example, if the formation of porosities is explained by the dynamics of the bath and that the regime is mainly associated with the absorption, what happens if we modify the energy transfer of the laser?

Cross-border Collaboration (if any)

- Collaborations with IK4-Lortek within the framework of an Aquitaine-Euskadi project whose objective was to develop a thermal instrumentation of a specific tool for FSW welding (2013) (Eric Lacoste and Egoitz Aldanondo for IK4).
- Collaborations with UPV within the framework of the thesis on the study of the interactions between a material (TA6V alloy) and the FSW welding process [Thesis G.J. Tchein, 2018] (Eric Lacoste and Franck Girot for UPV).
- Hosting of a UPV/EHU research associate, Dr. Amaia Torregaray, for 4 months (March to June 2017) (Corinne Arvieu and Eric Lacoste)
- Collaborations with Tecnalia and IK4-Lortek within the framework of the European project ENABLE (European network for alloys behaviour law enhancement) concerning a thesis on the in-situ control of the SLM process [Thesis P. Yadav, 2022] (Corinne Arvieu and Eric Lacoste).
- Publication with co-authors in UPV and IK4 Lortek :G.J. Tchein, D. Jacquin, E. Aldanondo, D. Coupard, E. Gutierrez-Orrantia, F. Girot Mata, E. Lacoste - Analytical modeling of hot behavior of Ti-6Al-4V alloy at large strain, Materials and Design, Vol. 161, 114-123, 2019
- Future project with ESTIA concerning WAAM process within the framework of BEST 4.0 which is a project of the IDEX of University of Bordeaux (Robin Kromer and Fabien Poulahon for ESTIA)