Johannes Hellstrom and Maria Sheahan  for Reuters:  General Electric launched bids on Tuesday to buy two of the world's top makers of machines for metal-based 3D printing - Sweden's Arcam and Germany's SLM Solutions - for a total $1.4 billion to bolster its position in the fast-growing technology.

3D printing has been used to build prototypes for decades but has become more widespread for industrial mass production in recent years, with uses including the production of dental crowns, medical implants and light aircraft parts.

GE has long been one of the main proponents of industrial 3D printing, using it to make fuel nozzles for its new LEAP jet engine in what marked a big step in using the technology in mass production.  Cont'd...