Residual stresses and surface damage when micromachining 6061-T6 aluminum alloy

The use of micro/nano-scale machining in the production of miniaturized products that are used in various industrial applications such as biotechnology, electronics, optics, medicine, and aviation has increased drastically in the past two decades. To maintain the functional quality of these products, it is essential to investigate and know the machining parameters that are needed to produce high-quality products. An attempt was made to investigate the effects of tool geometry, cutting speed, and undeformed chip thickness on the residual stresses and quality of the machined surface using an orthogonal micro-machining process. A modified deflection-etching technique was used for the residual stress analysis and determination, and the machined surfaces were examined using a scanning electron microscope. For the cutting conditions used in this experiment, compressive residual stresses were formed in the surface region. Surface damage in the form of grooves, cracks, voids, fractured areas, and scratches were observed for all the specimen machined in this study. The radius of the tool cutting edge measured from the photomicrograph of the scanning electron microscope was approximately 50 µm, which was higher than the depth of the undeformed chip thicknesses used in this work, which resulted in an inefficient cutting process wherein a significant portion of the energy was expended to plastically deform the machined surface region. This has led to surface damage in the form of grooves, cracks, voids, fractured areas, and scratches and induced compressive residual stresses in the surface region.