Experimental investigation of influence of post-processing variables on mechanical strength and surface quality of 3D printed carbon fiber reinforced polylactic acid samples

Material extrusion (ME) became widely accepted additive manufacturing method for producing customized polymer and fiber-reinforced polymer components, offering cost-effectiveness, speed, and minimal material waste. However, the parts printed are having lower mechanical characteristics and surface finish. Appropriate selection of post-treatment variables contributed to a marked improvement in the surface smoothness and mechanical attributes. In this research work, the influence of post-processing control factors namely type of chemical, exposure time, annealing temperature, and annealing time on mechanical properties and surface roughness was investigated. Experimentation with three levels design and multi-objective optimization was performed using Taguchi and grey relational analysis (GRA). The results shows that tensile strength, flexural strength, shore D hardness, and surface finish were improved by 21%, 11%, 5%, and 92% respectively. The key factors influencing mechanical strength are found to be annealing temperature and annealing time, at 95 °C and 150 min, while chemical type and exposure time are more significant for surface characteristics, with chloroform and 60 s exposure time being optimal parameters. The optimal parameters for multi-objective optimization have been determined as follows: ethyl acetate, exposure time of 40 s, annealing temperature of 95 °C and annealing time of 120 min. Optimized post-processing conditions enhance the mechanical properties and surface quality of end-use products made through fused filament fabrication, thus boosting the potential of the 3D printing industry.