Effect of process parameters on the Selective Laser Melting (SLM) of tungsten

Selective Laser Melting (SLM) is a promising technique for the fabrication of complex net shaped parts of many metals. However, the high melting temperature of tungsten makes fabricating complex parts via SLM difficult. A study was undertaken to understand the effect of process parameters like hatch spacing and scan speed on the densification of tungsten by the SLM technique. Experiments were conducted at hatch spacing of 15 and 30 μm and scan speeds in the range 200-1400 mm/s. A constant laser power of 90 W and a powder layer thickness of 30 μm were used. Rectangular cuboids of 7.8 ± 1.4 mm × 10.1 ± 0.1 mm × 10.1 ± 0.04 mm were printed using various process parameters and analyzed for densification. The densification of tungsten was found to increase with an increase in energy density. A maximum density of 75% theoretical was achieved at energy density of 1000 J/mm3.