Evaluation of the strength characteristics of biodegradable polymer structures fabricated by a 3D printer using different nozzle scan patterns

Abstract

Poly (lactic acid) (PLA) is a typical biodegradable polymer used as a material for fused deposition modeling (FDM) 3D printers sold commercially. The FDM system deposits material extruded from a tiny scanning nozzle to construct an object. (i) The user selects an appropriate scan pattern from several choices at the outset of the process. (ii) The user can also select an interior filling percentage (IFP) appropriate for the ultimate use of the object. (iii) Exposure to moisture degrades the mechanical properties of objects fabricated with the PLA material. How these three factors relate to the mechanical characteristics is unclear as of this writing. As a consequence, the user is confronted with a difficult choice of parameters when designing and fabricating a structure through this process. In this study we used tensile tests to evaluate the strength characteristics of test pieces prepared by an FDM 3D printer using four different scan patterns. The strength characteristics of the FDM test pieces were then compared with tensile testing results on test pieces formed by an injection molding method. The data obtained in this paper will be applied to structural design when the FDM 3D printer is employed for fabrication.