Parametric study of multi-roller rotary burnishing process

Abstract

Single point burnishing of low strength alloy with cylindrical shape and small diameter may lead to bending and failure of sample. Thus, there is limitation applying sufficient pressure to the sample that may lead to inappropriate quality characteristics or long time machining due to further pass number. Using hydrostatic pressure through series of face to face roller can be used as potential method for processing of specimens in aforementioned categories. In the present investigation an attempt was made for processing of AA6061-T6 samples which were turned to 8 mm diameter of by multi-roller rotary burnishing process. Experiments were designed and conducted to correlate factors viz burnishing depth, number of rollers, spindle speed and feed rate to surface roughness, surface residual stress and hardness. Analysis of variances have been carried out to check adequacy of developed empirical models and to identify factors with great importance on quality characteristics. Finally, an optimum processing condition was defined by response surface methodology and fatigue life and surface integrity factors of optimum condition were compared with as turned material. The obtained results revealed that feed rate, roller number and spindle speed are factors with great influence on surface roughness, residual stress and hardness respectively. It is also find out that low cycle fatigue life of the sample at optimum level are improved more than three times compared to as turned sample. The outcome of this research can be useful for processing of small size products that need to be surface treated to enhance their properties.