Computer-Aided Techniques in Manufacturing of Large Hydro Turbine’s Blades

Abstract

Blades are one of the vital components and most difficulty in manufacturing of large hydro turbines. In order to cost-effectively and productively manufacture these kinds of blades, hydro turbine manufacturers have been trying to machine these large blades using 5-axis CNC machining techniques in recent year. To implement 5axis simultaneous CNC machining for large blades, a series of computer-aided techniques in manufacturing of these blades have been developed. This paper presents the major computer-aided techniques that we have been developed in manufacturing of large hydro turbine blades, which include that Geometrical design of hydro turbine blades for manufacturing, Computer-aided location and the machined error evaluation by means of 3dimensional digitized measuring, tool path generation strategy to meet requirements of enhancing machining efficiency and controlling deviation in NC machining, tool path generation and NC machining simulation by establishing a virtual NC machining environment for blades; A reasonable and feasible strategy and the systematic scheme for manufacturing for large blades by using 5-axis simultaneous CNC machining are also purposed. The developed computer-aided techniques have been successfully applied in manufacturing of both the large Kaplan and Francis hydraulic turbine blades, it shows that higher efficiency and the better surfaces finish accuracy can be achieved in machining of large blades with the right combination of these techniques.