next at the high end spectrum where quality is most important and when you want to use materials like metals, you need a way to achieve higher temperatures as well as control the deposition of metals,

there are several methods to do this such as

-Laser Sintering/Melting (a laser melts target area of metal powder to bind the power into a solid piece of metal) there are a number of variations to this technology)

these machines cost anywhere from 500k+ an Shapeways started with 10 of these...probably have more now


-electron beam melting, (aka super high end version of lasers) (instead of a laser, it is an electron beam, the power source being a electron beam requires a vacuum, but the benefit of this over laser melting is that it can melt and weld metals that are extraordinarily resistant of heat and wear aka refractory metals as well as different types of metals at once achieving deeper weld penetration and contamination free. materials such as titanium, and super-alloys require this level of power and accuracy to build fully dense, void-free, ready to use parts.
(this can be used on metal powders, or melting a metal wire to create the part)
(this is used in space by nasa as a tool to makes parts where there's no gravity, and where there's no waste of materials.)

these machines cost idk... millions due to the electron beam equipments