Machining Property in Smoothing of Steeply Curved Surfaces by Elastic Emission Machining

In optics fields, an extremely smooth surface with a complex form is necessary for the lens and mirror used in advanced optical systems, although their surfaces are still difficult to polish. Here, we describe the machining of steeply curved surfaces by rotating-sphere EEM (elastic emission machining). Thus far, the use of rotating-sphere EEM has been limited to flat and gradually curved surfaces in spite of its high performance. We demonstrated the successful application of rotating-sphere EEM to a glass cylinder, resulting in a decrease in RMS (root mean square) surface roughness from 0.30 to 0.16 nm.