Analytical process model for wire + arc additive manufacturing

Sergio Ríos,Paul A Colegrove,Filomeno Martina,Stewart W Williams

doi:10.1016/j.addma.2018.04.003

Sergio Ríos, Paul A Colegrove + Show 2 more

Open Access

https://doi.org/10.1016/j.addma.2018.04.003

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Abstract

An analytical process model for predicting the layer height and wall width from the process parameters was developed for wire + arc additive manufacture of Ti-6Al-4V, which includes inter-pass temperature and material properties. Capillarity theory predicted that cylindrical deposits were produced where the wall width was less than 12 mm (radius <6 mm) due to the large value of the surface tension. Power was predicted with an accuracy of ±20% for a wide range of conditions for pulsed TIG and plasma deposition. Interesting differences in the power requirements were observed where a surface depression was produced with the plasma process due to differences in melting efficiency and/or convection effects. Finally, it was estimated the impact of controlling the workpiece temperature on the accuracy of the deposit geometry.

Highlights

Additive Manufacture (AM) is a recent fabrication technology, which consists of building parts by consecutively depositing layers of material, onto a substrate
Wire + arc additive manufacture (WAAM) is a variant of AM, currently under development at Cranfield University, which is based on welding processes such as metal inert gas and plasma welding [1]
The first set (Table 1a) corresponds to 17 deposits made with pulsed-Tungsten Inert Gas (TIG) WAAM [22], 4 of which were duplicates

Summary

Introduction

Additive Manufacture (AM) is a recent fabrication technology, which consists of building parts by consecutively depositing layers of material, onto a substrate. Wire + arc additive manufacture (WAAM) is a variant of AM, currently under development at Cranfield University, which is based on welding processes such as metal inert gas and plasma welding [1]. This process can provide significant reductions in the material required to produce a part which reduces cost, as well as shortening lead times. The main geometrical parameters to control are the effective wall width and the layer height (Fig. 1). These dimensions are inherited from the weld pool, in a similar fashion as the weld reinforcement in a welded seam. They result from the interaction between power from the arc, travel speed, deposition rate, inter-pass temperature and material properties

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