They can, but the expense of using this as a mfg process is generally prohibitive. I've read there are some advanced aerospace parts such as turbine blades w/ c

They can, but the expense of using this as a mfg process is generally prohibitive. I've read there are some advanced aerospace parts such as turbine blades w/ complex hollows or internal parts that require very advanced castings that it actually makes sense to use SLS as a build method. A good example of part-strength is the 1911 Solid Concepts in Austin printed late last year[0]. They used a EOSINT M 270, a pretty advanced and expensive SLS printer. [1] For reference, that 1911 ran about $600k in build cost. yeesh. [0] - http://www.thetruthaboutguns.com/2013/12/robert-farago/gun-review-solid-concepts-1911-dmls-direct-metal-laser-sintering/ http://www.thetruthaboutguns.com/2013/12/robert-farago/gun-r... [1] - http://gpiprototype.com/services/eosintm270.html http://gpiprototype.com/services/eosintm270.html