Mechanical testing of Additive Manufactured polymer components using Materials Extrusion Technology

Additive Manufacture (AM), where 3D components are built up layer-by-layer, is growing within the manufacturing industry. Among other advantages, AM offers new processing routes for the manufacture of components with intricate geometries that are impossible to make by conventional means. However, the current generation of AM techniques have limitations that need to be overcome, particular concerns arise around reliability and consistency in material properties of AM produced parts. This work investigates the mechanical properties of parts produced by material extrusion using a Makerbot Replicator 2 with Polylatic Acid (PLA) filament. A designed experiment was generated to establish process parameter settings for tensile test specimens. Orientation, resolution, infill density and number of shells were the process parameters investigated during the experiment. Tensile test specimens were printed to a recommended ISO test standard for polymers. Tensile testing was carried out. Data was collected for each test specimen, showing main effects and interactions between parameters. The results showed that altering the settings for number of shells, orientation and infill density had an effect on the tensile modulus. However, resolution had minimal effect on the tensile modulus, when altered between 270 and 100 microns. Specific mechanical standards for additive manufacturing in polymers currently do not exist. This work highlights the issues that need to be addressed by any new standardised test methods for AM and proposes changes in current methodology to overcome these challenges.