Verificación de características dimensionales de piezas elaboradas con la tecnología de modelado por deposición fundida (FDM)

This article is focused on evaluating the dimensional and geometric characteristics of a part made
by a 3D printer that uses material extrusion technology. To evaluate these characteristics, a
reference part designed with specific characteristics and nominal values was manufactured that
allows the dimensional and geometric errors of the part to be calculated from the evaluation of the
differences between the measured values and the nominal values of the characteristics. The purpose
of the evaluation is to quantitatively identify the behavior and limitations of the printer, through
the design and manufacture of a reference part. This work was developed in four stages, first a
reference part was modeled in computer-aided software (CAD). Subsequently, the reference part
was printed in five different positions on the work platform of a 3D printer. Next, the dimensional
characteristics established in the design of the part were measured using a coordinate measuring
machine (MMC) and finally the data were analyzed through a multivariate analysis. In this investigation, the multivariate analysis showed that the mean (X̅) of the measured values of the characteristics of the reference part is adjusted to the means (µ) of their nominal values established
in the design, which confirms that the measured values and the nominal values fit a normal
distribution. In addition, a flatness test showed that the reference pieces presented differences that
may be attributable to the fact that the printing platform of the printer under evaluation is not
completely flat, presenting a decline in the lower areas. Finally, through a linearity analysis, it was
shown that the characteristics of circular and rectangular holes, identified as, (CIR_Y) and
(DR_ZM) respectively, present high correlation coefficient values and this allows the generation
of simple linear regression models to estimate the possible geometry errors behaviousin the printer,
allowing for reliable adjustments or compensations at the reference part design stage.