Process optimization of laser sintered PA 12/MWCNT nanocomposites

Abstract

Rapid prototyping technologies are able to build parts in different materials and it is possible to obtain very unique composites with distinctive properties. Among rapid prototyping technologies, Selective Laser Sintering (SLS) is an interesting technology because it uses materials like metals, ceramics and polymers and obtained parts have good mechanical properties. Despite the properties that are possible to obtain with standard SLS materials it is possible to explore new composites to generate unusual properties. In this work it was investigated the mixture of carbon nanotubes to standard polyamide powder used in the SLS process. The aim of this work was to improve mechanical properties of the generated composite. Nevertheless, SLS process has many variables that need to be set and optimized to achieve the desired material processability and properties. The studied influence factors were the laser average power, the laser scanning speed and the carbon nanotubes content in the polyamide matrix. The study was developed using statistical methods to achieve optimal combination of the factors. In order to obtain optimal experimental factors, it was performed a factorial design evaluating laser power of 1.35, 2.70 and 4.05W, laser scan speed of 36.3, 39.9 and 44.5mm/s and multi-walled carbon nanotubes (MWCNT) weight of 0, 0.5, 1.0 and 3.0%. Results showed strong correlation between the factors that affected the obtained mechanical properties.