Advanced Structures & Composites Center

Orono, Maine — An article by ASCC researchers Sunil Bhandari and Roberto A. Lopez-Anido was published in Progress in Additive Manufacturing. The paper, titled, “Coupled thermo-mechanical numerical model to minimize risk in large-format additive manufacturing of thermoplastic composite designs” uses a simplified physics-based numerical simulation to determine a suitable combination of the parameters that will avoid the collapse of the deposited layer under self-weight – minimizing the manufacturing risk of large-format 3D-printed parts in a trial and error type approach. This publication is open-access and can be freely downloaded and distributed.

The collapse of deposited thermoplastic composite material under self-weight presents a risk in large-format extrusion-based additive manufacturing. Two critical processing parameters, extrusion temperature, and deposition rate govern whether a deposited layer is stable and bonds properly with the previously deposited layer. Currently, the critical parameters are determined via a trial-and-error approach. The simulation uses the discrete-event thermal model sequentially coupled with a finite element mechanical model to calculate viscous strains. The simplified physics-based numerical simulation can determine a suitable combination of the parameters that will avoid the collapse of the deposited layer under self-weight. The suitability of the processing parameters is determined based on the maximum plastic viscous strains computed using a sequentially coupled thermo-mechanical numerical model. This computational tool can efficiently check if a combination of temperature and extrusion rate causes layer collapse due to self-weight, and hence minimize the manufacturing risk of large-format 3D-printed parts. The source code for the discrete-event thermal model and the coupled thermo-mechanical model can be found
at here with additional information here.