Preparation and laser sintering of limestone PA 12 composite

The purpose of this paper is to report on the development of a new type of sustainable material, limestone/polyamide 12 (PA12) composite for Laser Sintering (LS). The material system is low cost, environmentally friendly, energy efficient, with good forming accuracy and mechanical strength. Different types of powder blends with different mixture ratios were created through mixing limestone and PA12. Single layer sintering was performed to determine the suitable mixture ratio. Demonstration parts and tensile bars were fabricated using LS under different processing parameters. These variations were chosen to investigate the effect of the energy input and the part bed temperature on densification, mechanical strength and microstructural evolution. Limestone/PA12 mixed in a ratio of 1:2 by volume has been shown to be extremely processable by LS, resulting in a material with good mechanical strength and apparent forming accuracy. The strength of the prototype increased with increased energy density. The average tensile strength was 9.8 MPa, exceeding the minimum tensile strength of solid limestone. There was also low void fraction with even dispersion in the part. This is the first study to combine inexpensive limestone powder into PA12 to develop a sustainable and low-cost limestone/PA12 composite as the feedstock for LS. (C) 2014 Elsevier Ltd. All rights reserved.