| Abstrakt: |
The trend toward the scalability of fused filament fabrication requires strategies to reduce printing time. One way consists in using calibrated nozzles with larger diameters. However, the reduction in manufacturing time is accompanied by reduced printing resolution and changes in the control of the material's viscous behavior. In this work, the parametric calibration was performed on a 1 mm diameter nozzle printing cubic models in polylactic acid. The procedure was divided into three steps: (i) identification of printing defects; (ii) systematic parametric study (based on Taguchi method); and (iii) interactive parametric refinement. The calibration of the 1 mm nozzle involved the analysis of six fused filament fabrication variables: layer thickness, extrusion temperature, extrusion multiplier, infill speed, perimeters speed, and first layer speed. Their effects were analyzed considering esthetic quality, dimensional and shape conformity, mass, and compression modulus variation of the parts. Despite the high degree of customization of fused filament fabrication printers, the results show that switching to a larger nozzle is not "plug-and-play". The user needs to know the correlations between the printability of the material and the effects of the variables involved in slicing, especially extrusion multiplier and layer thickness. Both variables act directly on the main problem of printing with a 1 mm nozzle, controlling the extrusion volume with the best accommodation of the material between and within layers. The main contribution of the study highlights that large diameter nozzles can induce poorly distributed accumulations of excess material, which decreases the quality of surfaces, deforms parts, destabilizes dimensions, and disorganizes the mesostructure (reducing rigidity) of the models. Finally, the parameter refinement process defined a base configuration for future studies to improve 3D printing with 1 mm nozzles. [ABSTRACT FROM AUTHOR] |
