Investigação da operação de alargamento dos furos usinados em pistões de ferro-carbono sinterizado

Abstract

The reaming operation has wide application in industry, for producing holes with high quality allied to low production cost and is therefore used in various parts in different materials. This study aims to investigate the reaming operation of holes machined in sintered iron carbon pistons, used in hermetic compressors for house hold refrigeration. The experimental design was developed to examine the influence of depth of cut, cutting speed and feed rate on the quality of the holes, evaluated through the accuracy of the diameter, roughness Rq and roundness deviation. It was also considered the behaviour of the axial force and torque acquired during machining. Additionally, images in a scanning electron microscope (SEM) were obtained for characterization of the machined surface. The results showed that the geometry of the reamer associated with the geometry of the hole might affect the quality. SEM images of the surface and roughness profile indicated that the surface pores characteristic of the machined material, were clogged during machining, in the cutting conditions tested in this study. It was also found that intermediate values of depth of cut (0.10 and 0.15 mm), cutting rate (30 and 35 m/ min) and feed rate (0.33 to 0.38 mm/rev) produce holes with better quality.