Comparative Analysis of the Strength properties of Specimens Printed from Three Different Types of 3-D Printers

Additive manufacturing is a fast-growing technology that is gaining prominence in the manufacturing industry as an alternative to conventional subtractive manufacturing methods largely because it enables the production of complex shapes without significant changes to the manufacturing layout. Additive manufacturing is a broad technology consisting of  Stereolithography (STL), Fused Deposition Modeling (FDM), Powder Bed Fusion, Binder Jetting, Direct Metal Laser Sintering, and Laminated Object Manufacturing. FDM is one of the most commonly used Additive manufacturing technology which is significant for rapid prototyping complex parts layer-by-layer with low cost. It has been observed that the most common parameters for selecting the best Fused Deposition Modeling (FDM) machines are mechanical properties of printed parts, printing style, post-processing, and amount of waste. As different types of 3-D printers are introduced, further research is needed to study the mechanical strength of the product from different printers. In this research, the mechanical properties of 3-D printed specimens from three 3-D Printers (MakerBot, Flash Forge, and PRUSA ) is studied to analyze the variation in the material strength. A simulation was performed on SOLIDWORKS -a computer aided design software- to examine the optimum properties of the test specimens. An ASTM D638 specimen is printed with the three listed 3-D printers, and a physical testing was performed on the specimens. The physical test that is performed on the specimens is tensile testing by using a TESTRESOURCE universal testing machine. To ensure uniformity in chemical and physical composition, polylactic (PLA) filament is used for printing throughout the experiment on all 3-D printers. The filament is melted at various temperatures and various printing speeds to observe how the temperature and the printing speed affects the strength of the printed specimen. The filament is melted at extrusion temperatures of 200 ^oC, 205 ^oC, and 210 ^oC while controlling the printing speed at 50 mm/sec and 100 mm/sec . Based on the analyses, the average critical load from 12 specimens of each printer is 397.98 lb for MakerBot, 430.17 lb for Flash-Forge, and 303.73 lb for Prusa. Flash-Forge has the highest average critical load in comparison to the other 3-D printers in this experiment. This load was used for the SolidWorks simulation which results in maximum strength of 7464 psi while the average strength of the specimen printed with flash-forge is 7148 psi, which is 498 psi difference.

Keywords: Polylactic (PLA); MakerBot; PRUSA; Flash-forge; Printing Speed; Extrusion Temperature; Additive Manufacturing; Fused Deposition Modeling (FDM); Tensile Stress