Comparative study of rotational and longitudinal turning: Energy efficiency and surface roughness in machining normalized medium-carbon steel

This study compares rotational and longitudinal turning during the machining of normalized medium-carbon steel. The aim is to evaluate differences in energy efficiency and surface quality. Three tools were tested: two rotational turning tools with 30° and 45° inclination angles and a conventional longitudinal turning tool. Thirty-six cutting experiments were performed while varying depth of cut, feed, and cutting speed. Cutting forces were measured in three directions and used to calculate specific cutting forces and total mechanical work. Surface roughness was evaluated using arithmetical mean roughness and maximum peak-to-valley height parameters. The results show that rotational turning, particularly with a 30° inclination, reduces specific cutting forces and enables lower energy consumption at comparable productivity. It also provides better surface finish at medium and high feeds. Longitudinal turning generated acceptable energy levels but produced significantly rougher surfaces. The findings highlight the role of tool inclination in improving energy-surface-quality interactions.