Aplicação do método Taguchi para otimização de parâmetros na furação do aço ABNT 4340 com brocas de aço rápido revestidas e não revestidas

• Ano de defesa: 2019
• Autor(a) principal: Otavio dos Santos Pereira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Furação; TiNAl; TiN; Taguchi; Revestimento; Força de avanço; Ra; Nitreto de titânio; Revestimentos; Taguchi, Metodo de (Controle de qualidade); Engenharia mecânica
• Link de acesso: http://hdl.handle.net/1843/RAOA-BCGHBC

In this work, the Taguchi methodology was applied to identify the input parameter levels (coating, cutting speed and feed rate) that generate the best results in the output parameters: feed force (F) and surface finish (Ra), during drilling of steel ABNT 4340. For this, 16 + 16 dry holes were made in samples prepared from ABNT 4340 steel, following the L16 orthogonal array suggested by the Taguchi methodology in a CNC vertical machining center. Tools used were ABNT M2 HSS drills, with 6 mm diameter, DIN 338 standard, coated by PVD technique and uncoated. Tools (coated and uncoated), the cutting speed (c) and feed rate () were selected as control parameters. The mean roughness values of the finished holes surfaces were measured using a surface roughness tester. The mean values of feed force were obtained during the drilling tests by piezoelectric dynamometer assembled in the machining center. The data were analyzed in Minitab 17 software configured for Taguchi's "smaller is better" function. Analysis of variance ANOVA was used to determine the control factors that most affect the surface finish (Ra) and the thrust force (F). TiN, TiNAI and TiNAI-M (multilayer) coated drills were analyzed by MEV and the mean layer thicknesses observed were 2.752, 3.545 and 3.340 m respectively. For the surface finishing (Ra) the coatings were the most impacting factors (71.9%) for the reduction of this parameter. Although the TiNAI-M coating was indicated by the Taguchi methodology as the best performance, the coatings obtained close results. The cutting speed (c) and the feed rate () did not present a significant contribution in the tested conditions (13.8% and 0.5%, respectively). For the thrust force (F), the coating presence was as impacting as the feed rate (38.9% and 35.0% respectively) and the cutting speed (12.8%) did not show a significant contribution. The TiN-based coating was indicated by the Taguchi methodology as the one with the best performance, with the lowest feed rate () and the lowest cutting speed (c) for the reduction of the feed force (F). Confirmation of the results was necessary only for the surface roughness (Ra), which together obtained results for F, proved the efficiency of the Taguchi methodology .