You take what nobody wants or needs anymore (bits of dead bodies), weld them to what has never lived, and create something functional, something greater than the sum of its parts. You may call yourself as a necromancer inventor, or a deadhead, or an osso-mechanic, but people in your occupation are mostly referred to as re-animators.
Technically speaking, you are a kind of wizard, though you and the wizards would both prefer to ignore this. Wizards blow themselves up or get turned into a frog too often for your liking, and wizards are
horrified by your monstrosities jealous that you have never even come close to blowing up or getting turned into a frog.
There is another kind of necromancer, the sort that raises spirits and commands the dead and explodes corpses (what is it with wizards and explosions?!?). This is not what you do, though some historian of magic has surely traced the relationship between your schools and who it was that first dispensed with spirit-calling in favor of necro-engineering.
Nowadays, re-animators are more common than necromancers, at least in the Lake Countries. In Quillsylvania, their art is distrusted but not outright banned (the necromancers cannot claim as much), and they occupy a place of prestige in Buckeye, which has long been sympathetic to those whose clever minds are called by others “mad.” As yet, there has been no ‘mortechnological revolution,’ but the re-animators are continuing to refine their art and some of them see, however distant it may be, the glimmer of a day when their work has revolutionized the world.