Investigação de desvios geométricos no alargamento de ferro fundido com ferramentas revestidas

Abstract

During the manufacturing of an internal combustion engine block, the drilling is the most common machining operation, and the holes produced require further operations in order to improve the form quality and the surface finish. Reaming is such operation, frequently used after drilling. The present work uses a Statistical Experimental Design to investigate the influence of the reamer geometry (margin width), the cutting parameters (cutting speed, feed rate and depth of cut) and the tool coatings (TiAlN, Alcrona® e Helica®) on the hole qualities (roundness, cylindricity and surface roughness) during reaming of grey (GH 190) and compacted graphite Iron (CGI 450). The results showed that Helica® was the best tool coating to machine the grey cast iron and Alcrona® was the best to machine compacted graphite iron. It was also found that the bigger depth of cut (0.25mm), the thinner margin width (0.10mm), the lower cutting speed (40m/min) and the higher feed rate (0,50mm/rev) produced holes with better quality in terms of form deviation and surface roughness.