Abstract: Much of the amount of machining allowance for a blisk is removed in the rough milling, so improving the cutting efficiency of the tunnel rough machining is key to realizing high efficiency machining of blisks. According to the structure characteristics of the tunnel of an open blisk, a 4-axis plunge rough milling with high efficiency and low cost is studied. The rough milling region of the open blisk tunnel is determined by generating the ruled envelope surface of the blade’s offset surface, and the algorithm of tool paths for 4-axis plunge milling is given. By using a ruled surface to approach a freedom surface, the problem of getting the boundary is solved, and the error arising from tool paths’ computation is avoided by the algorithm. Experiment shows that the 4-axis plunge milling can reduce the cutting force by 60% and improve rough machining by more than 100%.

Key words: open blisk, plunge milling, rough milling of a tunnel, ruled envelope surface, tool path