Effect of the degree of particle melt on mechanical properties in selective laser-sintered Nylon-12 parts

Abstract

Selective laser sintering (SLS®, a trademark of 3D systems Inc.) is a manufacturing process which has emerged from numerous other technologies as the leading process considered viable for rapid manufacturing (RM). SLS of polymers has found use in a wide range of industries ranging from aerospace to medicine. The ability to manufacture easily parts that previously have been difficult or impossible to produce, without tooling, has proved invaluable for many applications. A major area of focus within RM is the requirement to produce parts with more repeatable mechanical properties than can currently be achieved. This research has investigated the use of a novel method of interpreting a differential scanning calorimetry curve to indicate the level of melting within semicrystalline selective laser-sintered parts, or the degree of particle melt (DPM). The DPM has been shown firstly to be affected by the amount of energy input into the process whereby, as the energy input increases, the DPM also increases. Results have also shown that, as the DPM increases, the tensile strength and elongation at break also increase, whilst there is no significant effect on the Young's modulus. These findings will enhance the ability to optimize and predict the properties of the SLS process, an area which is critical when producing end-use parts, particularly when considering demanding applications such as in the aerospace and automotive industries.