Additive technologies have gained a significant importance over the past few years as they enable the fabrication of components of complex geometries and cost reduction by reducing material wastage. This thesis discusses the process of wire and arc additive manufacturing (WAAM) using G3Si1 (VAC 60) filler wire on mild steel plate. A favorable welding parameters with which we achieve quality welds were defined. We investigated the interconnection of welding voltage and current depending on contact tip to work distance and created a theoretical model that describes their interconnection. We found out that using the created model, it is possible to infer the wire stick out length with great accuracy based on measurements of welding voltage and current in real time. We also defined the response time of the WAAM system to an unforseen change in the substrate geometry and the ability to adjust the welding parameters to maintain the stability of the welding process.