Optimization of Precision Boring Conditions to Enhance the Surface Integrity of a Landing Gear Component

Boring process, also referred to internal turning, is commonly used to machine critical features of landing gear components like struts, brackets, and main cylinders. Over the past years, extensive research efforts have addressed the stability of the process by developing instrumented boring bars and advanced monitoring techniques. However, although the surface integrity characteristics, particularly the residual stresses, are crucial for structural components, it hasn’t been considered and its evolution over the boring conditions still not well understood. Hence, the present paper proposes a comprehensive investigation on the effects of boring conditions on the surface integrity of the aluminum alloy 7175-T74 commonly used in landing gear components. A parametric analysis has shown that lower cutting forces and surface roughness can be achieved using a larger insert nose radius. It was also found that feed rate, cutting speed and depth of cut experienced strong interaction effects with the machining mode (dry/wet) regarding the resultant cutting force and surface roughness. Results have also shown that wet boring conditions generated compressive residual stresses. An optimal boring condition was obtained using Grey relational analysis (GRA) – Taguchi method. Further investigation is required to refine the obtained optimal machining condition by considering the GRA results and the parametric analysis outcomes.