ArchaicArcane posted this link on another thread and it is a great article for setting expectations
http://gizmodo.com/why-3d-printing-i...t-fo-508176750
The way that I can see me using this technology now for metal sewing machine parts is to use the 3D printer to make a "master" and then use my traditional molding/casting process for making the actual part using the master that we 3D printed.
Someday soon we should be able to print in solid metal, just not yet.