Rapid prototyping by consolidation of stainless steel powder using an electrical arc

Abstract

Purpose

The purpose of this paper is to investigate the feasibility of using a pulsed Tungsten inert gas arc to fully melt and consolidate stainless steel powder onto a stainless steel substrate. The technology aims to bridge the gap between selective laser sintering or laser melting and wire fed weld deposition by providing good quality and better resolution at a lower cost.

Design/methodology/approach

Current settings between 5 and 30 A and frequencies between 0 and 200 Hz were used to consolidate stainless steel powder onto a substrate. Results were catalogued based on surface roughness using white light interferometery to develop a process map.

Findings

Velocity independent thresholds of current (17 A minimum) and frequency (20 Hz minimum) were found, with better quality achieved at higher pulse frequencies. The microstructure of the samples were examined showing grain sizes of ≈3 μm for equiaxed grains and up to 20 μm for the columnar grains. Vickers hardness measurements showed only a 20 point average hardness increase in the HAZ compared to the substrate.

Research limitations/implications

The study showed that although it was possible to deposit stainless steel tracks, it was not possible to reduce the track resolution to less than 400 μm at any of the process settings.

Originality/value

The research aims to investigate the use of a readily available, low cost, heat source to consolidate metal powder. The suitability of such a heat source for rapid prototyping is investigated using a variety of objective tests to provide a balanced view of its capabilities and limitations.

Citation

Rangesh, A. and O'Neill, W. (2011), "Rapid prototyping by consolidation of stainless steel powder using an electrical arc", Rapid Prototyping Journal, Vol. 17 No. 4, pp. 280-287. https://doi.org/10.1108/13552541111138405