Nowadays amongst additive manufacturing (AM) technologies, the Wire and Arc Additive Manufacturing (WAAM), process that uses metallic wire as filler and an arc welding process as a fusion source, is promising especially because of its high deposition rate, low cost raw materials, low material loss, and capability to manufacture large parts with an automatized system. On the other hand, the aluminum is a frequently used material in the industry, principally because its low density and mechanical properties, what make it interesting to be employed by AM processes. The present study focuses on the implementation of a Cold Metal Transfer (CMT) welding generator using an aluminum alloy wire (Al5Si) for AM applications. CMT process is a promising one for WAAM, thanks to its controlled current waveform and filler wire feeding that allow regular deposited weld beads. The aim of this work is to identify the relationships between the CMT welding parameters and the physical characteristics of deposited metal, in order to find the most suited parameters allowing a regular deposit. The CMT work parameters were evaluated in order to observe its effects on the morphological aspect of the deposited weld beads. Construction of multilayer metallic walls is achieved, and the presence of geometrical defects that could affect the correct wall formation was identified when the deposit is not continuous, with many ignition and stop cycles. Some propositions to decrease the presence of these defects are tested. Attempts of multi layers addition are presented, and relationship between these last results and CMT parameters is discussed.