Four-axis tool orientation smoothing for spiral machining of blades based on step length

A regular four-axis computer numerical control (CNC) machine is always used to produce blades by spiral machining method in many medium-sized and small industries. Generally, the four-axis CNC machine has the characteristic of low precision, which often leads to some obvious tiny tool marks like overcut on the blade surface. To overcome this problem, a tool orientation smoothing method is developed and implemented. Key issues are focused on tool orientation smoothing in four-axis spiral machining of blades, and concrete contributions are twofold. First, according to the primary curvature radii and parameter characteristics, the parameter range of blade surface is subdivided into four subregions. Second, tool orientation smoothing method for four subregions of blade surface is addressed in detail based on the step length of cutter contact (CC) points in four-axis spiral machining. A test shows that tool marks that easily occur in four-axis machining can be effectively reduced by using the proposed method.