Material propertiesAccuracy and mechanical property analysis of LPA12 parts fabricated by laser sintering

A new type of sustainable material, limestone/polyamide 12 composite (LPA12), has been developed for laser sintering additive manufacturing that is low cost, environmentally friendly and energy efficient. The purpose of this paper is to study the forming accuracy, mechanical properties and microstructure of sintered LPA12 parts affected by different energy input, including laser power and part bed temperature.The experimental results indicate that the dimensional errors in all directions are positive, there is little shrinkage during the sintering process, and higher thermal conductivity results in expansion of the prototypes. It is also found that energy input has a more significant effect on the forming accuracy in the Z (build) direction than on directions in the plane of the build. With increasing energy input, the forming accuracy is improved and reaches a maximum of over 98% for 25W laser power. The mechanical properties peak at 8.3 MPa for tensile strength and 33.5 MPa for flexural strength. At high energy, mechanical properties are degraded. Hence, for maintaining both forming accuracy and mechanical properties at the highest level, 25W of laser power and 175 °C−176 °C part bed temperature are appropriate processing parameters for sintering LPA12. The dispersion of limestone in the LPA12 prototype was examined by scanning electron microscopy (SEM). By comparing microstructural differences based on varying levels of energy input, the effect of energy input on the forming accuracy and mechanical properties is explained.