Experimental investigation of shaped metal deposition process by pulsed tig-wire technique

Shaped metal deposition using tungsten inert gas arc welding heat source is a novel additive manufacturing technique which can be used for fabricating solid dense parts by melting a cold wire on a substrate in a layer by layer manner. This work presents an extensive investigation (designing, constructing, controlling, mechanical properties, micro and macro-structural analysis etc.) of the shaped metal deposition process. An integrated additive manufacturing system was developed in order to reduce the lead time of the deposition process. The aim of this work is to investigate the designed additive manufacturing system capabilities about the part modeling and slicing, deposition-path planning, and the part deposition processes, as well as reporting the limitations of the developed system. This study aims also to develop a fundamental understanding of the mechanisms involved during the processing with a particular focus on single layer deposits and multilayers deposits of austenitic stainless steel. In the experimental investigations, continuous and pulsed TIG arc heat sources were used to be able to compare the resultant deposited part qualities. The results of this study have been used to form a shaped metal deposition process window for SS308LSi alloy. The developed system is capable of fabricating near-net-shaped metal components of maximum volume of 400 mm3 directly from CAD data with minimum buy-to-fly ratio and higher saving in waste material. The resultant deposited parts that were produced with pulsed current arc technique with relatively high frequencies, were observed that they all have good metullurgical bonding, defect free depositions, and high mechanical properties.