Comparative analysis of defects occurring in the layers of 3D-printed plastic parts using the FDM technology

The 3D printing process can be significantly improved by understanding the behavior of materials during printing, highlighting the differences in their physical and chemical properties. This understanding allows an analysis of the defects that appear between successively deposited layers, with the aim of reducing them or, in the best case, eliminating them completely. The elimination of these defects naturally leads to an increase in fracture resistance and, consequently, the durability of 3D-printed parts. This article analyzes the common defects that occur between the layers of plastic materials. The plastic materials examined in this study are Acrylonitrile Butadiene Styrene (ABS), Polylactic Acid (PLA), Polyethylene Terephthalate Glycol (PETG), Thermoplastic Polyurethane (TPU), and Nylon. Depending on the material used and the optimized printing process parameters, the defects between layers can vary significantly or may have similar causes. The most common defects analyzed in this study are poor adhesion of the first layer, weak adhesion between successive layers, and the occurrence of the warping phenomenon. The main objective of the paper focuses on analyzing these defects, understanding their causes, and proposing solutions for their prevention and correction. The discussions in this analysis will focus on the behavior of these materials in relation with the defects that may occur.