Aluminum alloys are used in the manufacturing of many products that require a high strength to weight ratio. In manufacturing of complex products we often reach the technological limits of conventional manufacturing methods or want to reduce costs and the amount of discarded material. To solve these problems, many types of additive technologies are being developed. This paper focuses on creating a database of parameters and optimization of the wire and arc additive manufacturing method for welding of AlSi5 aluminum alloy. The tests are made using a welding robot in combination with a synergic MIG/MAG welding machine and where CMT welding process is used. The emphasis is on the study of core welding parameters that enable quality welded walls to be made. Heat conduction and its distribution across the welded part is also studied. The results of this paper show that through good heat input management, it is possible to produce quality welded walls with widths up to 4,5 mm and material deposition efficiency above 80 % that, after additional machining, can be used for production of thin-walled products.