A new approach of modelling bottom edge cutting in four-axis roughing of blisk and its application on feedrate optimization

As important component of gas turbine engines, Blisks are complex in shape. The blisks are often rough machined in a four-axis machine tool with an end-mill, and the end-mill is fully engaged into the material to be removed. Because of the complex cutter motion in four-axis machining, the bottom edge of the end-mill is involved in cutting with a high possibility, resulting in undesirable cutting force increase, tool deflection and quick tool wear. To address this technical challenging, an analytical method to identify and evaluate the bottom edge cutting in four-axis machining is proposed in this work. The addition in cutting force caused by the bottom cutting edge are taken into consideration to precisely evaluate the overall cutting force. A feedrate optimization model is then established. The verification shows that the cutting force could be controlled by optimizing the feedrete without losing machining efficiency.