Competition between bead boundary fusion and crystallization kinetics in material extrusion-based additive manufacturing
Abstract
Assembling polymer beads into well-defined 3D geometries through a layer by layer deposition process, such as material extrusion additive manufacturing, remains challenging due to the complex interplay between the several kinetics involved (flow, inter-beads diffusion/fusion, cooling, solidification, etc). Here, we explore the influence of physical parameters like bead cross section geometry, partial bead fusion (also called bead coalescence or bead welding) and crystallization kinetics on the 3D printing of isotactic polypropylene as a model semi-crystalline polymer. New methods for the characterization of printed stacks cross sections, interlayer cohesion and viscoelastic coalescence are introduced. Our results demonstrate how printing conditions, through input parameters like layer height and nozzle temperature, can greatly affect interlayer cohesion in relation to polymer interdiffusion at the interface. We show that the relevant timescale for fusion is mainly driven by the polymer’s rheology, and that fusion is many-fold faster under Hertzian compression, i.e. due to the effect of contact pressure. Quantitative description of the influence of the extrusion nozzle and build platform temperatures on the crystallization time of printed beads highlights how the processability window is defined by the competition between fusion and crystallization. Our approach therefore provides a framework for the optimization of process parameters based on the physical processes involved during the production run of semicrystalline polymers.
Related
- Synthesis of PEDOT particles and manufacturing of electrically-conductive PEO / PEDOT thermoplastic composites by twin-screw extrusion
- Extrusion-based additive manufacturing of banana fiber reinforced PLA biocomposites with bioinspired infill patterns
- Crystallization for Manufacturing in Microgravity; Are We There Yet?
- Understanding the Ultrafast Crystallization Kinetics of Donor–Acceptor Semiconducting Polymers
- Porosity Formation Mechanisms and Their Effects on the Mechanical Properties of High-Density Polyethylene Extrusion Welds
BibTeX
@article{domenech2026competition,
title = {{Competition between bead boundary fusion and crystallization kinetics in material extrusion-based additive manufacturing}},
author = {Trystan Domenech and Pierre Ovlaque and Yves Trolez and Dominique Olivier and Benjamin Bujeau and Sébastien Charlon and Jérémie Soulestin},
journal = {Additive Manufacturing},
year = {2026},
month = sep,
doi = {10.1016/j.addma.2024.104395},
url = {https://imt-nord-europe.hal.science/hal-04819267v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Competition between bead boundary fusion and crystallization kinetics in material extrusion-based additive manufacturing
AU - Trystan Domenech
AU - Pierre Ovlaque
AU - Yves Trolez
AU - Dominique Olivier
AU - Benjamin Bujeau
AU - Sébastien Charlon
AU - Jérémie Soulestin
PY - 2026
DA - 2026/09/15
JO - Additive Manufacturing
DO - 10.1016/j.addma.2024.104395
UR - https://imt-nord-europe.hal.science/hal-04819267v1
AB - Assembling polymer beads into well-defined 3D geometries through a layer by layer deposition process, such as material extrusion additive manufacturing, remains challenging due to the complex interplay between the several kinetics involved (flow, inter-beads diffusion/fusion, cooling, solidification, etc). Here, we explore the influence of physical parameters like bead cross section geometry, partial bead fusion (also called bead coalescence or bead welding) and crystallization kinetics on the 3D printing of isotactic polypropylene as a model semi-crystalline polymer. New methods for the characterization of printed stacks cross sections, interlayer cohesion and viscoelastic coalescence are introduced. Our results demonstrate how printing conditions, through input parameters like layer height and nozzle temperature, can greatly affect interlayer cohesion in relation to polymer interdiffusion at the interface. We show that the relevant timescale for fusion is mainly driven by the polymer’s rheology, and that fusion is many-fold faster under Hertzian compression, i.e. due to the effect of contact pressure. Quantitative description of the influence of the extrusion nozzle and build platform temperatures on the crystallization time of printed beads highlights how the processability window is defined by the competition between fusion and crystallization. Our approach therefore provides a framework for the optimization of process parameters based on the physical processes involved during the production run of semicrystalline polymers.
SN - 2214-8604
SN - 2214-7810
ER -