Experimental an‎d Analytical eva‎luation of Surface Quality in the Turning Process of Hardened Materials Using Self-Propelled Rotary Tools

12/14/2026 12:00:00 AM

This study eva‎luates the performance of Self-Propelled Rotary Tools (SPRTs) when machining hardened steel. Machining hardened steel is facing enormous challenges due to its low thermal conductivity an‎d high hardness. SPRTs engage their entire perimeter of the inser‎t rather than a specific cutting edge, minimizing wear an‎d it becomes possible to machine hardened steels. Previous studies highlighted the significant effects of inclination angle on surface roughness so a holder was designed an‎d manufactured, allowing for the adjustment of the inclination angle by considering machining forces an‎d geometric conditions. Despite previous research that investigated only one inclination angle, in this research, the effect of both horizontal an‎d vertical inclination angles has been investigated, an‎d a new method for simultaneous application has been used. The optimal an‎d effective use of these inclination angles has significantly improved the quality of the machined surface. Hardened MO40 steel has been chosen as a workpiece. The full factorial design of the experiment is adopted, an‎d the effects of the horizontal an‎d vertical inclination angles an‎d feed rate in fixed tool (round inser‎t) an‎d SPRT turning have been eva‎luated, each in 3 levels with a total of 54 experiments. Additionally, the equivalent inser‎t radius was determined based on turning geometry, using this radius, a mathematical model was developed to predict surface roughness. The proposed model estimated roughness in fixed tool turning, with an R-squared value of 0.81, an‎d in SPRT turning, with an R-squared value of 0.76. In the best condition, the surface roughness was measured at 0.47µm in fixed tool turning an‎d 0.40µm in SPRT turning. In the second part of the study, the effect of surface texture on SPRTs in machining hardened 7075 aluminum was investigated using another experimental design. Four different inclination angles an‎d three types of inser‎t geometries were used, which included clockwise texture, counterclockwise texture, an‎d no surface texture, each under two conditions: dry an‎d wet. An average surface roughness of 0.44µm has been obtained by applying the clockwise surface texture, with the effective use of lubricant.

ابزار خودچرخان , اينسرت دايره‌اي , زاويه تمايل , زبري سطح , بافت سطح

Self-Propelled Rotary Tool , Round inser‎t , inclination angle , surface roughness , surface texture

Azizi

Dr.Davoodi_Dr.Akbari