The Research Of Helical Milling Of C/E Composites

C/E(Carbon/epoxy) composites wildly used in structural component of aircraft, because of excellent performance. When bore hole, C/E composites are easily delaminating, tearing and so on, for large cutting force and high cutting temperature. As new technology, helical milling has many advantages comparing to drilling, and drawing many attention. This dissertation aims at researching cutting force and cutting temperature when helical milling C/E composites. Main contents researched as follows:Modeling of helical milling cutting force. Based on helical milling kinematics principle, characteristic of helical milling and undeformed chip shape are analyzed. The peripheral cutting edge and the bottom cutting edge are engaged in cutting when helical milling, and cutting forms are different from each other, so cutting force modeling respectively is needed. Different cutting force modeling methods are compared and characteristics of helical milling are considered, helical milling force model is established based on mechanical milling force model and drilling force model.Helical milling cutting force model of C/E composites and force analysis. Calibrating experiments of cutting force coefficients of tool are designed, milling groove to calibrate peripheral cutting edge cutting coefficient and drilling hole to calibrate bottom cutting edge, so cutting force model of helical milling of C/E composites is established. Because of discontinuous cutting, cutting force of peripheral cutting edge is non-constant, so cutting force of single peripheral cutting edge is analyzed. With no axial force generate, cutting force of bottom cutting edge has little influence on bore diameter, so cutting force under different process parameters of peripheral cutting edge in cutting coordinate is analyzed, qualitative analyzed the effect of process parameters of peripheral cutting edge on bore diameter.Exit cutting temperature of helical milling of C/E composites. The helical milling experiments were performed with a special designed helical milling equipment on C/E composite. A thermal infrared imager is used to measure the cutting temperature after precision calibration using a thermocouple in a constant temperature oven. The effects of the processing parameters on the cutting temperature are analyzed. According to the kinematic principle of helical milling and the cutting principle, the origin of temperature are analyzed based on the shape and size of the undeformed chip. The results are helpful in understanding the machining mechanism of helical milling, and determination of the reasonable processing parameters of helical milling.