Fused deposition modeling (FDM) is a rapidly growing additive manufacturing
method employed for printing fiber-reinforced polymer composites. Nonetheless,
the performance of printed parts is often constrained by inherent defects. This
study investigates how the varying annealing parameter affects the tribological
properties of FDM-produced polypropylene carbon fiber composites. The composite
pin specimens were created in a standard size of 35 mm height and 12 mm
diameter, based on the specifications of the tribometer pin holder. The impact
of high-temperature annealing process parameters are explored, specifically
annealing temperature and duration, while maintaining a fixed cooling rate. Two
set of printed samples were taken for post-annealing at temperature of 85°C for
60 and 90 min, respectively. The tribological properties were evaluated using a
dry pin-on-disc setup and examined both pre- (as-built) and post-annealing at
temperature of 85°C for 60 and 90 min printed samples. Tribological tests were
conducted under varying normal loads (5, 10, 15, and 20 N) and sliding
velocities (1 and 3 m/s), following the ASTM G99 standard test procedure.
Significantly notable enhancements in wear and friction properties were
consistently observed across all tribometer test conditions when the composites
underwent annealing at 85°C for 60 min, surpassing the performance of other
samples. These particular samples, subjected to the 85°C/60-min annealing
process, exhibited elevated hardness, diminished wear rates, and reduced
coefficients of friction (COF). A detailed examination using a scanning electron
microscope revealed that the wear mechanism on the surface of the
tribometer-tested samples exhibited milder wear when carbon fiber was added,
followed by annealing at 85°C for 60 min, compared to the 90-min annealing.
These promising results suggest that the proposed composites have potential
applications in industries such as prosthetics, aerospace, and automobiles.