Fluidised bed finishing process for aeronautical applications: Environmental and technical-economic assessment

Abstract

The manual surface finishing process of aeronautical stators is time consuming and expensive. Moreover, this process is difficult to control and automate. To overcome these problems, this paper presents an innovative fluidised bed finishing process applied to turbine blades capable of guaranteeing compliance with the specifications in the absence of processing waste. Compared to the manual process performed by an individual operator, the fluidised bed process ensures the same quality in terms of surface roughness, with values of approximately 1 μm. It reduces the finishing costs of a single stator by approximately 80%, i.e., from € 769 to € 159, and increases productivity from approximately 42 units per year by manual processing to approximately 372 units. The significant increase in productivity is due to the possibility of processing an entire stator within the designed fluidised bed system. Despite an increase in the required investment costs, i.e., € 35,200 against € 1,000, the fluidised bed process guarantees a reduction in the main production cost items compared to that cost of a manual process, i.e., in terms of manpower (€ 2,703 vs. € 23,097) and processing materials (€ 4,346 € vs. € 6,906); this result, in combination with a significant increase in productivity, allows us to realise much cheaper processing than that with traditional methods. The performed life cycle assessment shows the excellent eco-sustainability of the fluidised bed process, and the corresponding environmental impact is much lower than that of the studied manual process, with a reduction of approximately 45% in the overall damage score, i.e., 11.598 pt vs. 21.094 pt. The traditional process is penalised above all by the considerable consumption of raw materials, i.e., 12.125 pt vs. 6.030 pt, which strongly affects the overall environmental impact. The fluidised bed process overcomes this problem and does not produce waste thanks to its high degree of automation and repeatability, therefore improving profits.