Development of Screw-Based 3D Printing Machine and Process Experiments for Short Fiber Reinforced Polymer Composites

Abstract

3D printing is one of the flexible additive manufacturing (AM) processes that can be used to fabricate parts from various types of materials such as polymers, metal, and ceramic. 3D printing process is one of the famous techniques for printing the product from the filament causing material degradation. Granule-based 3D printing or screw-based material extrusion 3D printing is an alternative process that can create the parts from plastic or composite granule raw materials. However, there are limited use and study in the designation of granule-based 3D printing and process parameters including material temperature, heat bed temperature, nozzle size, and printing speed. These process parameters play a significant role in the properties of 3D printing parts. Some parameters cannot be adjusted in the commercial 3D printing process. Thus, the purposes of this study are to develop a screw-based material extrusion 3D printing machine that can freely adjust the process parameters and to investigate the effect of 3D printing parameters on the appearance and mechanical properties of printed parts. Pellets of neat acrylonitrile butadiene styrene (ABS) and short glass fiber/ABS composites are used in the experiments. Six process parameters were studied, including % fiberglass, printing temperature, printing speed, nozzle size, % Infill, and heat bed temperature. Each parameter has 3 levels, which were designed by the Taguchi L18 method. The results were evaluated by the main effect plot method and showed that the printing speed, nozzle size, and %fiberglass are the top 3 parameters that affect tensile strength. The nozzle size, %infill, and %fiberglass are the top 3 parameters that affect Young’s modulus. The granule-based 3D printing machine was completely developed; however, the extruded plastic line from the nozzle was difficult to control resulting in poor product quality. Thus, the feedback control for controlling the screw-extruder speed and temperature will be developed in future work.