Chip Topography for Ductile-Regime Machining of Germanium

Ductile-regime response during the diamond turning of brittle germanium crystals is evident from the damage-free surfaces obtained. The nature of the ductile-regime processes cannot be determined by examination of the final machined surface itself. Machining chips were characterized using scanning electron microscopy. The chip topography provides insight into the ductile-to-brittle transition that occurs along the tool nose. A detailed examinaiton of the chips provides an independent estimate of the critical cutting depth for the transition.