Strength of PLA Components Fabricated with Fused Deposition Technology Using a Desktop 3D Printer as a Function of Geometrical Parameters of the Process

Abstract

The current paper is studying the influence of geometrical parameters of the FDM (FFF) 3D printing process on printed part strength for open source desktop 3D printers and the most popular material used for that purpose, i.e. PLA (polylactic acid). The study was conducted using a set of different nozzles (0.4, 0.6 and 0.8 mm) and a range of layer heights from the minimum to maximum physical limits of the machine. To assess print strength, a novel assessment method is proposed. A tubular sample is loaded in the weakest direction (across layers) in a three-point bending fixture. To explain the results obtained, a mesostructure evaluation through SEM scans of the samples were used. A significant influence of geometric process parameters was detected on sample mesostructure and, consequently, on sample strength.

Evaluation of 3D-Printer Settings for Producing Personal Protective Equipment

“…These differences are likely due to a difference in values used for layer height: [ 41 ] used values between 0.1 to 0.6 mm, whereas [ 34 ] were between 0.06 to 0.24 mm – closer to the values and behavior to those in this present study. Alternate testing methodologies may also account for these differences: [ 41 ] performed a three-point bend test, while [ 34 ] performed both three-point bending and tensile tests. Increasing line width, on the other hand, led to an increase in stress at failure by an average of 4.61 MPa.…”

“…This is likely a result of effectively increasing cross sectional area by decreasing the number of individual strands making up shelled areas of the print, which decreases overall void space. This mechanism has been previously described [ 41 ]. Researchers using varying nozzle diameters, and by extension varying line width, have demonstrated that an increased nozzle diameter/line width leads to increased tensile strength [ 41 ].…”

“…This similarity of performance agrees with existing research that showed our tensile samples that were printed flat, with varying layer heights had statistically significant but small (4.96%) differences in strength [ 34 ]. Interestingly, other research has determined that decreasing layer height can in fact increase strength [ 41 ]. These differences are likely due to a difference in values used for layer height: [ 41 ] used values between 0.1 to 0.6 mm, whereas [ 34 ] were between 0.06 to 0.24 mm – closer to the values and behavior to those in this present study.…”

“…Interestingly, other research has determined that decreasing layer height can in fact increase strength [ 41 ]. These differences are likely due to a difference in values used for layer height: [ 41 ] used values between 0.1 to 0.6 mm, whereas [ 34 ] were between 0.06 to 0.24 mm – closer to the values and behavior to those in this present study. Alternate testing methodologies may also account for these differences: [ 41 ] performed a three-point bend test, while [ 34 ] performed both three-point bending and tensile tests.…”

Pioneering low-cost 3D-printed transtibial prosthetics to serve a rural population in Sierra Leone – an observational cohort study

“…Before printing, the virtual 3D models were loaded in Cura (Ultimaker BV, Geldermalsen, the Netherlands), used as an open-source 3D printer slicing application, to create a transfer of the 3D model into a printable file (g-code). The socket was printed with a 0.8 mm print core, 100% infill, 0.2 mm layer thickness, and a print speed of 45 mm/sec [34,35].…”