Selective Laser Melting of Iron Essay Example | Topics and Well Written Essays - 250 words

Selective Laser Melting of Iron - Essay Example It is imperative to note that the carbon content of steel plays a critical role in determining processability of SLM. High carbon content also has adverse effect on high speed steel and SLM produced steel, since they portray a limited densification response. Wright et al. [2], in his research, found out that with increase in carbon contents, there is increase in the thickness of the carbon layer sifted on the melt surface. Just like the oxide layer, the carbon layer has a critical influence mostly on diminishing wettability and causing the melt to spheroidise rather than flow across the underlying surface. In addition to this, the brittleness of SLM manufactured high carbon content steel is increased by the formation of complex interfacial carbides at grain boundaries. Childs et al. [4], through his research, concluded that the dissolution of carbides is favored by increasing the heat flow in the treated powder. On the same breath, increasing heat flow homogenizes distribution of all oying elements. Thus, a thin powder layer thickness, which is less than 100mm, is more recommendable for laser melting. This is besides the optimization of laser types and parameters. Due to this reason, high volumetric energy density for both elemental homogeneity and powder consolidation is achieved [5-7]. In this process, heat generated from a CO2 laser is used to sinter systematic powder layers from 3D objects arranged layer by layer [8]. Due to this, the time required for tool making is considerably reduced. The basis of the sintering is the â€Å"liquid phase sintering mechanism.† The technique involves melting the powder partially. This is also termed as semisolid consolidation mechanism [9-10]. In this form of sintering, a minute amount of liquid phase (comprising between 1 - 10% by volume), with solubility for the solid considered to be at sintering temperature, is employed. When cooled, the liquid crystallize at