Variable Polarity GTAW in Rapid Prototyping of Aluminum Parts 369

This paper reports on a process to build aluminum alloy parts by variable polarity gas tungsten arc welding (GTAW). The relationship between the geometric sizes of the deposited layer and the welding parameters is investigated. A machine vision sensor is used to monitor and control the arc length that is a key welding parameter in the achievement of uniform deposition. By optimizing the depositing speed and the depositing layer thickness, there is no need for a cooling system to cool the part. Three Dimensional parts with different wall widths and different shapes are successfully obtained. The surfaces of the deposited aluminum parts are smooth and uniform.