Exploring the Environmental and Economic Benefits of Wire Arc Additive Manufacturing compared to Subtractive Manufacturing

Additive Manufacturing (AM) has demonstrated the ability to use materials more efficiently compared to subtractive manufacturing. Wire Arc Additive Manufacturing (WAAM), a new type of Directed Energy Deposition (DED) AM technique, is gaining popularity due to advantages like faster build rates, the capacity to construct large volumes, low-cost feedstock materials and machine tools compared to more established powder-based AM technologies. However, WAAM parts often exhibit lower dimensional precision and inferior surface finish compared to powder-based processes or machined parts, frequently needing postprocessing. This study assesses the environmental impact, production cost, and mechanical properties of WAAM and compares them to those achieved with traditional Computer Numerical Control (CNC) milling. A mechanical part made of high strength low alloy steel (ER70S) was produced using WAAM. Based on the life cycle environmental and economic data compiled, the authors constructed environmental impact and cost models utilizing Life Cycle Assessment and Life Cycle Costing techniques. Additionally, uniaxial tensile and hardness tests of the WAAM part were undertaken to evaluate its mechanical properties. Overall, WAAM was observed to be the most eco-friendly choice due to its superior material efficiency compared to CNC milling and was more cost-effective when utilized in batch production for batch sizes over 3. Furthermore, it was seen that the environmental and cost-saving potential of WAAM was further improved when implemented for manufacturing large products. The fabricated WAAM part displayed good mechanical properties comparable to those of its parent material. The methodology and experimental data presented in this study can be utilized to perform similar assessments for other products and can guide manufacturers in selecting the most sustainable manufacturing process.