2.3.1 Fabrication of Filament PLA Composites
For proper material flow, PLA was mixed with 1% surfactant after the composition was finalized (5%/8%/6%). The filaments are manufactured in-house using a single screw filament extruder. Table.2 contains the specifications of a single screw extruder as well as the input parameter conditions. When the barrel temperature and extruder flow were raised above 160 °C, the extrusion rate increased, but porosity on the outer surface was discovered. Air bubbles formed in the extruder as a result of the fast extrusion, and porosity developed in the filament. When the barrel temperature is kept below the specified range, the pellets remain un-melted and are not properly bonded with the ingredients.
<<<Table.2 Feedstock Material Extruder Specification>>>
The temperatures were finally identified and ranges were given in Table.2 after trial and error methods. The surfactant in the materials provides good material flow and an excellent outer surface with a filament diameter of 1.75 mm. In the absence of surfactants, the surface of the filaments was not good, and non-uniform diameters were observed. There were two types of test specimens fabricated, such as composite specimens and composite sandwich specimens. For composite specimens, full composite feedstock filament was used, and for composite sandwiches, PLA/PLA-Composite/PLA orders were followed until the specimens were completed.