RESEARCH PAPER Induction heating in a wire additive manufacturing approach Jean-Yves Hascoët 1 & Jérôme Parrot 1 & Pascal Mognol 2 & Etienne Willmann 3 Received: 20 June 2017 /Accepted: 23 November 2017 # International Institute of Welding 2017 Abstract In additive manufacturing (AM), three-dimensional objects are built layer by layer by joining each layer to the previous one. For metal parts, there are three main methods: powder bed, powder deposition, and wire deposition. This latter makes optimal use of the material in contrast to other processes, which makes it very interesting industrially. Indeed, with powder, the ratio between powder used and powder melted is not equal to one, in opposition of the use of wire. In order to ensure the proper melting of the metal, several methods already exist, including the use of lasers or electric arc. This paper presents a novel approach of wire deposition using inductive energy for additive manufacturing applications. This approach does not make use of a storage of the molten material. Instead, the tip of a metal wire is melted by an induction heating system. Inductive energy is also used to obtain an optimal thermal gradient between the tip of the wire and the substrate or previous layer. A numerical model has been developed and validated experimentally. It shows that the induction heating system is able to melt the tip of the wire and heat the substrate to create suitable deposition. Keywords Wire . Manufacturing . Simulating . Induction . Heating . Process parameters 1 Introduction There exists a variety of techniques, in additive manufacturing (AM), that build three-dimensional objects layer by layer by joining each layer to the previous one. It is also known as solid freeform fabrication (SFF), and it has evolved from early rapid prototyping manufacturing techniques. AM techniques are becoming very popular [1], because they are flexible, eas- ily automated, and capable of producing functional and complex objects of different materials, polymers being the most common ones. The use of AM for directly manufacturing metallic parts is very interesting, especially for objects with complex shapes and small production volumes. For these reasons, it is principally used in the medical, aeronautical [2], and die manufacturing indus- tries [3]. AM techniques for producing metallic parts can be sepa- rated into two groups [4, 5]: (a) those which—in a first step— metal powder is put into a container before melting it locally to create the first layer of the part, and—in a second step—again covers powder and locally melting for the second layer, until the part is finished. And (b) those which directly deposit the metal corresponding to this cross-section (Direct Electron Deposition, DED) and, if necessary, use auxiliary support structures. Selective laser melting (SLM), selective laser sintering (SLS), and electron beam melting (EBM) are some examples of techniques included in the first group [6]. Functional graded materials (FGM) are also studied. This technique can couple two—or more—materials during the deposition process to create better mechanical characteristics and/or bio-compatibility of the part [7, 8]. This article is part of the collection Welding, Additive Manufacturing and Associated NDT * Jean-Yves Hascoët jean-yves.hascoet@ec-nantes.fr Jérôme Parrot jerome.parrot@ec-nantes.fr Pascal Mognol pascal.mognol@ens-rennes.fr Etienne Willmann etienne.willmann@eder.fr 1 Ecole Centrale Nantes, Institut de Recherche en Génie Civil et Mécanique (Gem) – UMR 6183, CNRS, 1 Rue de la Noë, 44321 Nantes, France 2 Institut de Recherche en Génie Civil et Mécanique (Gem), École Normale Supérieure de Rennes, Campus de Ker Lann, 35170 Bruz, France 3 EDER, Pa de Monteno, 56190 Trinité Surzur, France Welding in the World https://doi.org/10.1007/s40194-017-0533-y