Researching on the factors influencing the critical undeformed chip thickness of single crystal germanium

Cutting in ductile mode is a prerequisite for mirror machining of single crystal brittle materials. Under the condition that the cutting thickness is less than the critical undeformed chip thickness, the single crystal brittle material is removed in ductile mode. The critical undeformed chip thickness of single crystal brittle materials is not an intrinsic parameter, but a variable related to stress conditions, crystal orientation and other factors. In this paper, aiming at the critical undeformed chip thickness of single crystal germanium, the influence of the changes of crystal orientation, tool rake angle and linear velocity on the critical undeformed chip thickness of single crystal germanium is investigated by means of constant linear velocity single point diamond turning. The experimental results show that critical undeformed chip thickness of single crystal germanium varies in different crystal orientations. Large tool negative rake angle can increase the critical undeformed chip thickness of single crystal germanium. Increasing the linear velocity within a certain range can increase the critical undeformed chip thickness of single crystal germanium, however, excessive linear velocity will worsen the cutting state and reduce the critical undeformed chip thickness. This study provides some references for ductile mode cutting of single crystal germanium and other brittle materials.