This paper proposed a CNC interpolator based on block overlap, capable of changing acceleration and deceleration time constants during continuous machining. The time constant can be set individually for each block through G-code commands. A velocity profile generation algorithm is proposed to set different time constants for both acceleration and deceleration phases. This algorithm can be applied to short blocks. The block overlap algorithm can be used for corner smoothing. A simulation model of the CNC interpolator was constructed to evaluate the proposed interpolation algorithm. Simulation results demonstrated that the proposed algorithm increased precision in areas with significant angular changes by adjusting time constants while simultaneously reducing machining time.

The kinematic constraints used in a computerized numerical control (CNC) interpolator are one of the main factors determining a machine tool’s machining accuracy. The CNC generates velocity profiles by applying kinematic constraints such as jerk and acceleration. Therefore, changing the kinematic constraints values can adjust the cycle time and cornering error. This study proposes a method to adjust the kinematic constraint values. First, the relationship between CNC kinematic constraints and cornering errors were analyzed. The relationship between the kinematic constraints and the cornering error was expressed as an analytical solution. Kinematic constraint values that satisfy specific cornering error values were selected using the analytical solution of cornering error. Finally, a method was devised to apply the appropriate kinematic constraint values to each machining section within a part program. The analytical solutions for cornering errors and using different machining segments to control cornering errors were verified using tool path generation simulation.

This paper proposes a cycle time estimation algorithm of a CNC machine tool, using a block overlap based tool path generation algorithm. Velocity profile generation algorithm of CNC interpolator is proposed to compute the cycle time of the G-Code block. Because the CNC blends adjacent velocity profiles to reduce the cycle time and smooth the tool path, the cycle time is adjusted considering the block overlap. The in-position time of rapid traverse is compensated to improve the cycle time estimation accuracy. The simulation model was designed to estimate the cycle time of the CNC machine tool. A three-axis feed drive testbed was used to evaluate the cycle time estimation accuracy of the proposed algorithm.