Control of Helical Blade Machining in Whirling

Machinings of helical blades have recently been increased with manufacturings of aircrafts and energy facilities. The helical blades have generally machined in ball end millings on the multi-axis machining centers. Because high machining rates and low machining costs have been required for the blade machinings, more effective processes are required to improve the machining performances. This study applies whirling process to the blade machinings. The whirling process is performed in the workpiece and the tool rotations with eccentricity of their centers. A mechanistic model is presented to control the blade shape in the whirling process. Then, the cutting tests were conducted with a turning tool on a turning center. In the presented cutting, the helix angle and the helical orientation are controlled by the feed rate and the ratio of the tool spindle speed to the workpiece one, respectively. The machining errors and the surface finishes were also measured in whirling of the blades. The machining error at the free end of blade is larger than that of the clamping side of blade. The surface finish at the clamping side is worse than that of the free end of blade, which is induced by the vibration of the tool.