Impactos ambientais decorrentes de processos de fabricação na usinagem de metais

Abstract

This paper aims to analyze the environmental impact magnitude resulting from the realization of some traditional machining processes variants (in all, twelve variants of the drilling, milling and turning processes) in five different metal types (steel, chrome steel, cast iron, aluminium and brass), using for this seven databases (ILCD, Impact, ReCiPe, TRACI, UBP, CML and EDIP) of a life cycle impact analysis software version called GaBi. A brief description of the drilling, milling and turning processes was given along with an explanation of conventional processes and CNC processes, as well as the metal types considered in the study and GaBi with its databases. A brief explanation was also given about the products life cycle. The databases provided various values of physical quantities that quantitatively characterize various environmental impact indicators (these values refer to the simulated execution of machining processes variants in 1,0 kg samples of the metals considered in this paper). These indicators were organized into sixteen environmental impact categories (this paper also briefly describes these sixteen categories). Within each database, for each metal type, the values of each environmental impact indicator were normalized taking into account the machining processes variants. After that, the arithmetic mean of these normalized values was calculated for each machining process variant, taking into account all available environmental impact indicators. By repeating this process for all metal types from all databases, it was pointed out which variants are more and less environmentally impacting. The seven databases unanimously pointed out the dressing operation performed on a CNC mill as the most impactful, while also unanimously the seven databases pointed out the conventional drilling process as the least impacting. For the sake of exemplification, all the environmental impact indicators tables available for the EDIP database, including all of their normalized values, were added to Appendix A, in addition to the environmental impact indexes of the traditional machining processes variants.