The Future of Additive Manufacturing: Modern Technology with Historical Origins in Welding

Abstract

This article traces the historical lineage of metal additive manufacturing (AM) from ancient solid-state forge welding through modern wire arc additive manufacturing (WAAM), arguing that today's AM boom builds on centuries of welding technology development rather than representing an entirely new field. Beginning with the 1600-year-old Iron Pillar of Delhi, an early example of solid-state additive fabrication via forge welding, the narrative progresses through the development of fusion welding technologies—oxy-acetylene and electric arc welding—made possible by 18th–20th-century advances in gas and electrical power equipment. Early 20th-century automation innovations, including automatic wire feed and mechanized torch movement, enabled "shape" or "form" welding, in which mid-20th-century engineers built massive axisymmetric components such as pressure vessels and flanges entirely from deposited weld metal. These techniques evolved into modern WAAM, now used to produce large-scale components on demand. The article highlights ongoing efforts to integrate automated in situ monitoring and nondestructive inspection into directed energy deposition AM and concludes that convergent manufacturing—combining multiple AM processes with monitoring, feedback, and post-processing into unified automated workflows—represents the next frontier.