A Study of Cutter Path in High Speed Rough Milling of Pockets. Part II: Modelling and Performance Evaluation

Large aeronautical parts, such as wing ribs, involve a volume of metal removed up to 90-95 % of initial weight, particularly pocket milling takes 60-70% of the total cycle time, so this operation plays an important role in the cost definition of the final product. Since typical materials in aircraft frames are aluminium alloys, High Speed Machining technology is convenient and more frequently used, also for rough operation. Using modern production system cutting velocity and feedrate are relatively high also in rough machining. It is important to determine cutter path and position vs time law in order to allow the lowest machining time and to control machine dynamic conditions. In this paper linear trajectory and cubic spline trajectory are compared in terms of execution time during high speed rough machining of pockets; in this part the comparison is numerical. The results indicate time saving using spline interpolation and the influence of feedrate and acceleration profile about above cutter paths. This is important information to select best cut condition and machining performance.