Orthogonal cutting of Wire and Arc Additive Manufactured parts

Pedro P Fonseca,Catarina Vidal,Tiago A Rodrigues,Telmo G Santos,Valdemar R Duarte,Carla M Machado,Francisco Ferreira

doi:10.1007/s00170-022-08678-3

Abstract

This work aimed to evaluate whether the established scientific knowledge for machining homogeneous and isotropic materials remains valid for machining additively manufactured parts. The machinability of thin-walled structures produced through two different variants of wire and arc additive manufacturing (WAAM) was studied, namely conventional MIG deposition and the innovative hot forging variant (HF-WAAM). Cutting operations were carried out varying the undeformed chip thickness (UCT) and the cutting speed, using a tool rake angle of 25°. A systematic comparison was made between the existing theoretical principles and the obtained practical results of the orthogonal cutting process, where the relation between the material properties (hardness, grain size, yield strength) and important machining outcomes (cutting forces, specific cutting energy, friction, shear stress, chip formation and surface roughness) is addressed. Additionally, high-speed camera records were used to evaluate the generated shear angle and chip formation process during the experimental tests. The machinability indicators shown that, through the appropriate selection of the cutting parameters, machining forces and energy consumption can be reduced up to 12%, when machining the mechanical improved additive manufactured material. Therefore, it has been confirmed the feasibility of machining such materials following the traditional machining principles, without compromising the surface quality requirements.

Highlights

Toward following the new paradigms of industry, the need for mass customization, combined with higher productivity and efficiency levels, led to the rise of Additive Manufacturing (AM) [1]
The first sample was produced with conventional WAAM, while the second sample was produced with the Hot Forging Wire and Arc Additive Manufacturing (HF-WAAM) variant
Evaluating the low-alloy thin-walled steel structures manufactured through WAAM and HF-WAAM (Fig. 2), is noticeable the superior spattering presented on the hot-forged component, sustained by the higher measured values of surface waviness (1210 ± 25 μm), when compared to the measured values for the conventional WAAM structure (977 ± 63 μm)

Summary

Introduction

Toward following the new paradigms of industry, the need for mass customization, combined with higher productivity and efficiency levels, led to the rise of Additive Manufacturing (AM) [1]. AM is the process of joining materials to make objects from three-dimensional (3D) model data, created layer-by-layer, with versatility and cost-efficiently. Current advantages over traditional manufacturing processes are the high potential for process automation, the reduced amount of total production time, flexibility, costs, and less material waste, as well as the benefit in design freedom. A wide range of materials can be processed by these technologies. Powder-Bed Fusion (PBF) [8] and Directed Energy Deposition (DED) are the most used AM techniques. In DED processes, focused thermal energy is applied to, simultaneously, melt and deposit the material into the surface, where it solidifies. Different types of primary heat sources can be used: arc plasma, electron beam or laser combined with powder or wire used as feedstock material

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