Laser sintering of parts with complex internal structures

Laser sintering of prototypes or parts using metallic powder as base material has reached a certain level of quality concerning 'simple' geometries. Realizing complex internal structures though, still is a challenge. Internal structures can be complex internal channels/cavities to provide thermal optimization, mechanical or hydraulic functions. Other examples are internal repeating patterns like honeycombs to reduce the weight or porous internal structures to be used in air or water filtering, fluid flow control or noise reduction. Here the laser sintering process and its constraints regarding the production of internal structures are reported. Post treatment requirements are discussed. Results of attempts to produce lightweight materials by modified process parameters during laser sintering are shown. It is referred to the improvement of material properties of parts by using alternative laser scanning strategies. Materials used are tool steels and stainless steels.