A novel five-axis rough machining method for efficient manufacturing of centrifugal impeller with free-form blades

This paper presents a novel methodology and algorithm for efficient manufacturing of the centrifugal impeller with free-form blades. Aim at the character of the centrifugal impeller blade surface, by the mathematical analysis and comparing method between the impellers with the free-form blade and ruled blade, the approximated blade with ruled surfaces is proposed as the simpler target for the rough machining of the impeller. For the slighter twist and efficient calculating, three machining areas are obtained by the two adjacent facing blades and the splitter, and four machining layers are obtained by intersections between the blades/splitters and hubs which have the same shapes but different locations along the direction from hub to shroud. The tool paths on each sun areas and layers are divided into two parts. Two computational methods of the tool axis and feed rate number are proposed to achieve the consummate equilibrium of the efficiency and the wanted profile for the following finish machining. The novel five-axis rough machining tool paths are calculated and a practical machining mold is presented.