Rheological Aspects of Foaming Process in 3D Printing

Additive manufacturing of foamable materials has recently garnered significant attention as complex parts with greater design flexibility can be obtained with less manufacturing time as well as being lighter and with lower cost. When using extrusion-based 3D printing techniques, it is necessary to consider both, the printability of the material and the foaming process, taking into account that the foaming process can happen during the printing process itself or after it. This work explores the possibility of controlling the cellular architecture of foamable polylactic acid (PLA)/chemical foaming agent formulations processed by Fused Deposition Modelling (FDM). Capillary rheometry, small amplitude oscillatory shear (SAOS) and extensional viscosity (EVF) measurements will offer insights into the printability and foamability of PLA formulations at processing temperatures. The decompositon temperature of the chemical foaming agent will be determined by thermogravimetry. Scanning electron microscopy (SEM) will facilitate the assessment of the degree of foaming attained during printing.