CHIP TOPOGRAPHY FOR DUCTILE-REGIME MACHINING OF GERMANIUM

Ductile-regime response during the diamond turning of brittle germaniu m crystals is evident from the damage-free surfaces obtained. The natu re of the ductile-regime processes cannot be determined by examination of the final machined surface itself. Machining chips were characteri zed using scanning electron microscopy. The chip topography provides i nsight into the ductile-to-brittle transition that occurs along the to ol nose. A detailed examination of the chips provides an independent e stimate of the critical cutting depth for the transition.