Probing dimensional consistency during multi-track multi-layer gas metal arc directed energy deposition of aluminium alloys

Abstract

The dimensional consistency of multi-track multi-layer parts fabricated by gas metal arc-directed energy deposition is by far the most critical challenge. A systematic investigation is presented here to examine the influence of the important process variables such as wire feed rate, printing travel speed, and resulting energy input per unit length on the dimensional consistency and surface waviness of multi-track and multi-layer parts made by gas metal arc directed energy deposition using an aluminum alloy filler wire. The current and voltage transients are monitored in real time to realize a quantitative measure of the arc power and energy input per unit length of deposition on the build profile and its dimensional consistency. The dimensional consistency and the surface waviness of the build profile are measured by optical microscopy. The microhardness distribution of the sample builds along the tracks and layers is also examined for different process conditions and the effect of energy input per unit length on microhardness distribution has been examined. The evaluation of the experimentally measured results shows that the dimensional inconsistency and surface unevenness of the deposited profiles can be reduced significantly by increasing the energy input per unit length for gas metal arc-directed energy deposition.