V-shaped cutting by straight blade tool has been proposed as a typical process to quickly remove large volumes of Nomex honeycomb. To meet the process requirements of V-shaped cutting by robots, a major problem is that the six degrees of freedom of the straight blade tool must be precisely programmed. In this paper, a path planning method for the V-shaped robotic cutting process is presented. The determining method of path parameters for cylindrical parts is firstly analyzed, with an optimization model proposed. The position of path points is pre-generated by robotic machining module of CAM software, and machining files in the robot language are output. Considering the requirement of V-shaped cutting path, a special post-processing program is developed to translate the CAM software generated machining files into final files for V-shaped cutting, which converts the reciprocating milling path into the V-shaped processing path and adds the orientation data of the path points. Furthermore, the robot machining files generated by the post-processing program are verified in MATLAB. V-shaped cutting experiments on Nomex honeycomb were carried out using 6-axis robot and ultrasonic cutting system to verify the presented method. Results show that the cylindrical surface of the machined workpiece is consistent with the expectation. INDEX TERMS path planning, V-shaped cutting, Nomex honeycomb, robot processing, straight knife.