High speed interpolation for micro-line trajectory and adaptive real-time look-ahead scheme in CNC machining

Abstract

CNC machining plays an important role in mechanical manufacturing. A key issue is to improve the machining feedrate while keeping the machining precision and satisfying the acceleration constraints of the CNC machine. For the consecutive micro-line segments interpolation, the velocities at the junction of two segments are the bottlenecks for the machining efficiency. This paper proposes a multi-period turning method to improve the feedrate at the junctions using the linear acceleration and deceleration mode, which utilizes the maximal acceleration capabilities of the NC machine while satisfying the machining precision. A new and more efficient look-ahead method and a feedrate override method are also proposed to boast the global machining speed. The proposed algorithm has been implemented on Blue Sky NC System, and experimented in real material manufacturing. Compared with several existing algorithms, the current algorithm can improve the manufacturing time ranging from 50% to 180%, depending on the machining parameters, and also results in better machining quality. In addition, the algorithm also satisfies the need of real-time interpolation.