Indirect selective laser sintering of metal parts with overhung features

The manufacture of metal parts by indirect selective laser sintering (SLS) involves initially joining metal powders with a binder to form a fragile green part. The green part is then placed in a furnace where the binder is removed and the metal powder is sintered. An infiltrant such as copper or bronze can then be used to fill the pores in the structure to result in a fully dense part. For sections of the part which are supported from underneath the basic shape is usually retained to a reasonable accuracy during the furnace stage. However, unsupported features tend to fracture or warp. This paper describes a way of manufacturing metal parts with overhanging or unsupported features, by combining new SLS technology with traditional foundry technology.