High temperature rheological behavior and sintering kinetics of CF/PEEK composites during selective laser sintering

As a kind of high performance polymer with excellent mechanical strength, high temperature property and chemical resistance, the polyether-ether-ketone (PEEK) and its composites are the promising candidates that can satisfy the demands for high stiff and lightweight in aerospace industry. So it is very attractive to fabricate PEEK and its composites parts with additive manufacturing technology, especially the selective laser sintering (SLS), due to its advantage on the fabrication of the parts with complex geometries. However, the strengths of the PEEK and its composites prepared by SLS are obviously lower than their injection molded parts and the laser sintering kinetics of the PEEK composites is seldom studied. In this paper, to fabricate the carbon fibers (CF) reinforced PEEK composites with high strength by SLS, the sintering kinetics of CF/PEEK composites was thoroughly studied based on the high temperature rheological behavior. A novel effective melting zone was defined by combining the simulated temperature distribution with the viscosity-temperature relationship and used to predict the process planning. Finally, the calculation results were validated by employing the simulation parameters in experiments and the tensile strength of CF/PEEK composites reached 109 +/- 1 MPa with an elasticity modulus of 7365 +/- 468 MPa, which is 85% higher than injection molded pure PEEK. Therefore, methods in this work could be considered as a complement to the numerical analysis of SLS process and the reinforced CF/PEEK composites may be used in aerospace industry for the structure optimization and lightweight design with complex geometries.