Parametric analysis for slot milling of carbon fiber reinforced polymers based on ultrasonic machining

Carbon fiber reinforced polymers (CFRP), have got rapidly enhanced applications in aerospace and other fields due to their attractive properties of high specific strength, high specific stiffness, and low thermal expansion. However, their properties like inhomogeneous, anisotropy and low heat dissipation are the main hindrance for machining of such materials with desired quality. In this research, the feasibility analysis was carried out and found that ultrasonic machining is only feasible for CFRP-T700 with low an elastic modulus of 233MPa as compared to rotary ultrasonic machining. Analysis of variance was performed and found that spindle speed is the significant parameter for feed and axial direction cutting forces. The cutting depth has found as a significant parameter for axial and feed cutting forces whereas the feed rate found a significant parameter for the axial force only. The optimal combination of these three forces has investigated with spindle speed 5000 rpm, feed rate 175mm/min and cutting depth 1.0 mm. Further analysis showed that spindle speed and cutting depth are significant for surface roughness and the optimal values for surface roughness (less than 1.5 µm) can be found with spindle speed 3800 rpm, feed rate 220 mm/min and cutting depth 2.2 mm cutting depth. The analytical model for surface roughness has then developed and validated. The results will be much helpful for machining of slots based on ultrasonic technology also for the industry level for better quality and to save expensive CFRP materials.