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.