Study of Defects and Geometric Anomalies on Monolayer Parts Obtained by Fused Deposition Modeling Process

The Fused Deposition Modeling (FDM) process, commonly known as 3D printing, deals with the manufacturing of parts by the subsequent addition of layers of fused thermoplastic polymer. The parts obtained by this process can be used for domestic applications, rapid prototyping, or final applications. During the preparation of the printing model, in the process known as slicing, different process parameters must be defined, such as: extruder speed, extruder height in relation to the bed, bed temperature. Parameters that, if incorrectly defined, can lead to a series of deficiencies in the parts, such as low dimensional accuracy, low surface quality, reduced mechanical resistance and, eventually, the occurrence of several printing defects in the parts,
damaging or even preventing its use. The 3D printing process has a critical period, at its beginning, during the manufacturing of the piece’s first layer. The present work aims to study some of the types of geometric deformations observed in monolayer pieces when some of the printing parameters are improperly defined. Printing tests on monolayer parts were carried out with polylactic acid (PLA) polymer filament. A home grade 3D printer, model Graber i3 was used. The height of the extruder to the bed was altered in relation to the recommended value, and three pieces were printed for each height used. The printed parts were scanned at 1200 x 1200 dpi resolution, using a DCP-L2540DW model scanner. The images obtained were then analyzed using the Matlab software and the geometric characteristics of the pieces were compared. The study is a first step towards a better understanding of the defects and geometric anomalies obtained when an incorrect definition of basic parameters during the processing of the three-dimensional model happens.