An indicator of porosity through simulation of melt pool volume in aluminum wire arc additive manufacturing

Abstract

Managing the quality of functional parts is a key challenge in wire arc additive manufacturing. In case of additive production of aluminum parts, porosity is one of the main limitations of this process. This paper provides an indicator of porosity through the simulation of melt pool volume in aluminum wire arc additive manufacturing. First, a review of porosity formation during WAAM process is presented. This review leads to the proposal of this article: monitoring the porosity inside produced part can be achieved through the melt pool volume monitoring. An adapted Finite Element model is then proposed to determine the evolution of the melt pool volume throughout the manufacturing process of the part. This model is validated by experimental temperature measurement. Then, in order to study the link between the porosity and the melt pool volume, two test parts are chosen to access to two different pore distributions. These two parts are simulated and produced. The porosity rates of produced parts are then measured by X-ray tomography and compared to the simulated melt pool volumes. The analysis of the results highlights the interest of the melt pool volume as a predictive indicator of the porosity rate.

Wire and Arc Additive Manufacturing of a CoCrFeMoNiV Complex Concentrated Alloy Using Metal-Cored Wire—Process, Properties, and Wear Resistance

“…The welding direction was chosen in an alternating manner to compensate for thermally induced geometric errors on both sides of the resulting wall structure, Figure 1. A similar approach has already been shown in [35,36] and others. The welding parameters used to produce the wall structure are summarized in Table 2.…”

Toward steel strip insertion during wire arc additive manufacturing of aluminum alloy smart part

“…The thickness maps produced of the steel strip are presented (Figs. [8][9][10][11]. The color scale is presented in Figure 12.…”

“…The part made with WAAM technology shall be realized in a paramagnetic and metallic material such as aluminum alloy. Furthermore, the literature in aluminum alloy parts made by WAAM is well developed [8][9][10][11]. Moreover, the part has to be massive.…”

A Brief Review on The Common Defects in Wire Arc Additive Manufacturing

“…Wang, S., et al [107], In their study "The Influence of Heat Input on the Microstructure and Properties of Wire-Arc-Additive-Manufactured Al-Cu-Sn Alloy Deposits" they proposed that if the heat input is greater than 90 J/mm, then the pore size in the bulk material can be greater than 50 μm, and the formed grains were primarily columnar in the as-built state. Nicolas Béraud et al [108], Mentioned that the larger the volume of the melt pool, the higher the probability of trapping pore and thus the risk of increased porosity. E.M. Ryan [91], suggested that a larger weld bead size would limit the ability of hydrogen bubbles to escape to the surface, thus more pores can be formed.…”

“…Therefore, from the previous mentioned studies we can conclude there are several factors preventing or reducing pore formation in WAAM process. These factors are slower cooling rate [98], low process pulse frequency [98], higher interpass temperature [99,100], clean and high-quality wire [86,101,105], CMT technique [109] or CMT with advanced mode and pulsing current [101,110], lower total energy input per unit volume [89], avoid using alloy composition with great difference in solubility between liquid and solid metal such as aluminum alloys [102,103], vibrating workpiece [104], CMT mode combined with interlayer rolling [90], lower flow rate of shielding gas [87], equilibrium melt pool sounding pressure [25], equiaxed fine grain structure [106,107], smaller weld pool or weld bead size [91,108], stable or smooth arc [86], eliminate the existence of hydrogen around the weld pool as much as it is possible [92], and reducing the distance between the nozzle and workpiece during WAAM process [111].…”