An Initial Investigation of Tungsten Inert Gas (TIG) Torch as Heat Source for Additive Manufacturing (AM) Process

Author(s)

Moreira, Alcindo F. ; Ribeiro, Kandice S. B. ; Mariani, Fabio E. ; Coelho, Reginaldo T. ; Fratini, L ; Ragai, I ; Wang, L

• Document type: Journal article
• Source: 49TH SME NORTH AMERICAN MANUFACTURING RESEARCH CONFERENCE (NAMRC 49, 2021); v. 48, p. 7-pg., 2020-01-01.

Abstract

Additive Manufacturing (AM) processes are gaining more steam in the last years, due to a series of advantages, such as capability of producing complex parts never possible before, low stock to be removed, complex parts in exotic materials, etc. However, energy efficiency, high costs and longer fabrication time, could be some of the drawbacks in the future. Welding processes can be used to produce pieces by AM techniques and their application has been intensified lately. Commonly, AM processes use MIG/MG and TIG and primarily with wire as stock material. Welding offers the advantage of producing large parts in lower time and material consistency is always good, since those processes have been greatly improved. In contrast, welding workpieces, generally, result with rough surfaces and poor geometric quality, which makes them not readily acceptable for most of the common machinery applications. The present work investigates the use TIG process with metal powder as stock material to produce workpieces, which are to be post processed by machining The AM process is based on the Powder Bed Fusion (PBF) system. A simple one-axis moving system was produced to test the whole concept. Powder was preferred since it is readily available in variety of metallic alloys. Two powder grain sizes (Gs), three travel speed values (f) and three current levels (C) were tested producing weld beads of AISI H13 on a substrate of AISI 1020 plate. Beads were assessed by measuring external dimensions and looking at their microstructures. Additional tests were performed building straight wall stacking 10 layers with the best welding parameters found with the first trials. Results indicate that materials with good internal quality could be produced when making single beads and also building straight walls. These first trials show that the proposed process can be used as a promising hybrid process, using AM (PBF-TIG) and conventional machining at the same equipment. Future work will concentrate on adapting the welding and powder bed system in a machining center to further study the process. (c) 2020 The Authors. Published by Elsevier B. V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer review under the responsibility of the scientific committee of NAMRI/SME. (AU)

• FAPESP's process: 19/00343-1 - Control of directed energy deposition process for manufacturing complex geometry components by Additive Manufacturing (AM)
• Grantee: Kandice Suane Barros Ribeiro
• Support Opportunities: Scholarships in Brazil - Doctorate