Environmental Sustainability of Laser-Based Manufacturing: Case Studies on Laser Shock Peening and Laser Assisted Turning

Laser assisted manufacturing (LAM) processes, when compared with traditional manufacturing processes, have the potential to reduce cost, increase surface finish, extend part/tool life, and expand the range of manufacturable materials. However, very limited research has been done to evaluate the environmental performance of laser assisted processes and it is generally not clear how LAM processes compare with traditional methods. This paper conducts case studies on two representative laser based processes, i.e. laser shock peening of 7065 T7351 Aluminum and laser assisted turning of compacted graphite iron. Life cycle assessment is used to benchmark the environmental performance of these two processes to conventional processes, i.e. shot peening and dry turning, respectively. The life cycle inventory of both the laser based processes and conventional processes are developed using SimaPro v7.1 and Ecoinvent 2.0 and life cycle impact assessment is performed using US EPA TRACI. It is found that environmental performance of laser based processes varies significantly from process to process due to materials and energy consumption. Laser shock peening of aluminum has much better performance when over all environmental impact categories considered. Contribution analysis indicates that this is mainly due to the fact that laser shock peening does not need shot medium and at the same time significantly extends fatigue life of the workpiece. However, due to high electricity consumption and use of absorptive paint, laser assisted turning of compacted graphite iron has much higher environmental impacts than traditional dry turning, even after extending the tool life significantly.