Theoretical-experimental evaluation of different biomaterials for parts obtaining by fused deposition modeling

Although microFDM (microFused Deposition Modeling) has been widely used with biomaterials, there is not enough information about their flow models and the appropriate values for operating conditions. The aim of this paper is to provide a criterion to establish feasible ranges of temperature and shear stress to carry out fused deposition of the biomaterials studied at microscale (hundreds of mu m). Materials used were (acrylonitrile-butadiene-styrene), PLA (polylactic acid), and PCL (polycaprolactone). Polyvinyl alcohol was also included in this study, although its quick thermal degradation has led to poor dimensional stability parameters and, therefore, it has been considered inappropriate for this application. Viscosity models were obtained in a 300 mu m nozzle microFDM device manufactured by electroforming techniques. These models were used in a simulation analysis whose results show a relationship between the convergence of the algorithm and the characteristics of the filament obtained in equivalent experimental testing. Besides, melt fracture and relevance of swelling was assessed by optical microscopy observation. This information allows to define operating conditions (in terms of temperature and shear rate) to obtain homogeneous morphological characteristics of the microextrudate. Furthermore, the procedure stated could be used in tissue engineering to delimit feasible operating conditions to manufacture scaffolds by fused deposition modeling. (C) 2016 Elsevier Ltd. All rights reserved.