An investigation on high-efficiency profile grinding of directional solidified nickel-based superalloys DZ125 with electroplated CBN wheel

Abstract

Profile grinding is an established technology for manufacturing aircraft engine components with a high surface quality and a high dimensional accuracy, for instance, the dovetails of gas turbine blades. In spite of recent advantages, the employment of profile grinding has been impeded by drastic wheel wear and thermal damage, especially when machining difficult-to-cut materials such as titanium and nickel alloys. In this study, grinding experiments with directional solidified nickel-based superalloy DZ125 were performed with the aim to enhance the wheel shape retention, suppress thermal damage, and increase the material removal rate. Instead of conventional abrasive wheels, a monolayer electroplated cubic boron nitride (CBN) profile wheel was employed, and the measurement results showed that the dimensional deviation of the machined surface profile was within tolerance. An analysis of the specific grinding energy revealed that a low specific grinding energy can be achieved by effectively controlling the maximum chip thickness. Only a slight variation of the grinding temperature was measured in the grinding zone between different points along the profile when using a profile-adapted needle nozzle. For the grinding parameters used in this study, a high shape accuracy and a good surface integrity was obtained even at a specific material removal rate of 50 mm3/mm s and grinding in a single pass.