Direct Metal Laser Sintering produces 3D objects using a layer-bylayer method in which powder is deposited in thin layers. Laser beam scans over the powder fusing powder particles as well as the previous layer. High-concentration of laser energy input leads to high thermal gradients which induce residual stress within the asbuilt parts. Ti6Al4V (ELI) samples have been manufactured by EOSINT M280 system at prescribed by EOS process-parameters. Residual stresses were measured by XRD method. Microstructure, values and directions of principal stresses inTi6Al4V DMLS samples were analysed. OPSOMMINGDirekte laser metaal sintering vervaardig driedimensionele voorwerpe deur gebruik van ʼn laag-op-laag metode waar poeier in dun lae gedeponeer word. Die laser straal skandeer die poeier en smelt die deeltjies en die vorige laag aan mekaar. Die hoë konsentrasie van laser energie inset lei na hoë termiese gradiënte wat veroorsaak dat daar res-spanning in die onderdele is. Tot op hede is monsters vervaardig deur die EOSINT M280 sisteem teen voorgeskrewe EOS proses paremeters vir Ti6Al4V (ELI) poeier. Argon is gebruik as die beskermingsatmosfeer. Res-spanning is gemeet met die XRD (bestraling diffraksie) metode. Mikrostruktuur, waardes en rigting van hoof spanning in Ti6Al4V monsters is ontleed. INTRODUCTIONAdditive manufacturing (AM) is a relatively new manufacturing technology. From its development in the 1980s up to the present day, AM has developed at a rapid rate. Direct metal laser sintering (DMLS) is a type of AM that produces objects from metal powder deposited in a thin layer by selective laser scanning. The laser beam scans over the powder, thus melting the powder particles and the previous layer. Sequentially, track-by-track, layer-by-layer, a 3D part is sintered. DMLS can produce fully dense parts of complex geometry with internal structures and also light-weight lattice structures. This technique opens up new avenues, especially in the automotive, aerospace, and medical fields, where the unique design is required.Ti6Al4V alloy is a low-density, high-strength, extraordinarily corrosion-resistant material that is also biocompatible. Ti6Al4V is not only ideal for medical applications, but it is also one of the main alloys incorporated in aerospace applications due to its high strength-to-weight ratio. Ti6Al4V alloy is α-β titanium heat-treatable alloy, which makes it more attractive due to its versatility [3]. The Centre for Rapid Prototyping and Manufacturing at the Central University of Technology in the Free State, South Africa, specialises in producing implants from Ti6Al4V (ELI) powder.Modern DMLS systems such as EOSINT M280 system from EOS GmbH use fibre lasers with high power densities. For a laser power of 200 W and a spot size of 80 µm, power density reaches ∼40 kW/mm 2 . The concentrated heat input of the DMLS process leads to high thermal gradients that induce residual stress within the part. Knowledge about the values and directions of residual stress is of primary importance for manufacturing reli...

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