Desktop Metal, a billion-dollar start-up, promised to revolutionize manufacturing. It went bankrupt, and now has much humbler ambitions as the 3-D printing industry takes a sober turn.Desktop Metal, a billion-dollar start-up, promised to revolutionize manufacturing. It went bankrupt, and now has much humbler ambitions as the 3-D printing industry takes a sober turn. NYT > Business [ SOBAN NEWS: International and National ]