Abstract: The overlapping process of direct metal rapid prototyping using pulsed micro-plasma arc welding (PMPAW) is studied. An overlapping model between deposited tracks is established. The relationships between and among the overlapping parameters such as the ratio of width to height of the deposited tracks cross-section (l), the distance between deposited tracks centers and the overlapping ratio are analyzed and the effect of these parameters on the part building quality is studied. Some H00Cr21Ni10 stainless steel parts are built using different over-lapping parameters and the surface smoothness, tensile strength and elongation are tested. The experimental results show that the mechanical behavior of the part built with larger l value is better than that with smaller l value. The longitudinal tensile strength and elongation of the parts are better than transverse tensile strength and elongation. So a multi-directional scanning mode, I.e. alternatively scanning between two adjacent deposited layers, is adopted to build the whole isotropic parts.

Key words: Overlapping parameters, Pulsed micro-plasma arc welding, Rapid prototyping