Fused filament fabrication of carbon fiber-reinforced polymer composite: Effect of process parameters on flexural properties

Abstract

Short carbon fiber-reinforced polymer composites are desirable for many additive manufacturing (AM) applications as they are light and structurally strong. The process parameters in fused filament fabrication (FFF) significantly affect the mechanical properties of SFRP parts. In this work, three-point bending tests are carried out to investigate the flexural behavior of 3D-printed polyamide 12 carbon fiber (PA12-CF) specimens. An L18 Taguchi design of experiments with Gray relational analysis is applied to optimize the FFF parameters. It is shown that build orientation has the most influence on flexural properties and the distribution of short fibers has an additional effect. For a rectilinear infill pattern, the maximum flexural strength of the part was realized at the printing speed, layer thickness, and extrusion temperature of 30 mm/s, 0.15 mm, and 270°C, respectively. With these parameters, the flexural strength of the part is 119.9 MPa and the flexural modulus is 3038 MPa. For a concentric infill pattern, the flexural strength of the part is 15.8% higher at 138.8 MPa. The flexural modulus is also higher at 3692 MPa. This study's results contribute toward optimizing FFF parameters to suit the specific flexural loading requirements of an AM part.