Study on the surface degenerative layer in ultraprecision machining of KDP crystals

The ANSYS analysis method is employed to analyze the stress field distribution within the whole cutting region. The surface degenerative layer is studied by a nano-mechanical measurement system. The results show that, the forming mechanism of surface degenerative layer is the change stress distribution in ultra-precision turning. The tensile stress is major in machined surface. The stress and strain increase with the accretion of depth of cut, and decrease with the accretion of cutting speed. In the three elements of cutting quantity, the cutting speed has the largest impact on the thickness of degenerative layer, followed the depth of cut, and the feed rate has the smallest impact.