Perhaps manufacturing processes like laser sintering or 3D printing with a MIG welder have not become mainstream because traditional metalworking processes like casting, turning, and milling are so much faster and much more repeatable. Let me know when this thing can hold tolerances of +/- 0.0001". We'll probably have a cure for cancer by then.<p>Metal can be a tricky material to work with. It takes a lot of force manipulate. If you don't know what you are doing, you can very easily get seriously injured or even killed. To me, it would seem much more rational to try to build low-cost milling and turning centers that are small enough to move into a house without taking out the walls and simple enough to maintain where you don't need to have certified mechanics come every time you crash it. You're still going to have to make a considerable investment of time to learn how to safely and properly operate it, but that seems much more realistic scenario than emailing a file to grandma, having her put on her sunglasses, then pressing "Print," followed by 6 hours of sparks flying.<p>Don't get me wrong, I'm sure there are applications for additive metal manufacturing processes, but I believe that the cases where they are the best solution are few and far between.