Research Initiation: Ultra-Precision Machining of Glass Components

该项目旨在推进玻璃的高精度磨削技术，即“韧性磨削”，以消除表面断裂和亚表面损伤为具体目标。有了这项新技术，许多以前由于脆性而难以加工成精确形状的材料现在可以在一次磨削操作中加工成镜面表面。这种改进的材料去除过程是通过控制磨削进给到每砂轮转速低于100纳米的速率而实现的。该工艺适应延性规律，即使采用上述新工艺也不能完全消除玻璃磨削过程中的表面断裂。提出在砂轮与工件之间引入金刚石抛光浆，可首次实现单次加工加工高精度光学质量玻璃部件。将抛光浆引入磨削区域的另一个好处是，它将允许对大型（大于1米）光学部件进行超精密磨削，这在以前被认为是不可能的应用，因为在玻璃加工中金刚石砂轮会迅速变钝。在这种应用中，研磨/抛光联合方法具有相当大的优点：通过不断修整砂轮，松散的磨料解决了砂轮磨钝的问题。同时，通过磨削提供的刀具位置的精确控制克服了抛光操作中遇到的固有轮廓不精确。

This project is to advance the technology of high-precision grinding of glass, known as "ductile regime grinding", with the specific aim of eliminating surface fracture and subsurface damage. With this new technology, many materials that have previously been difficult to machine to accurate shapes because of their brittleness can now be machined to mirror finishes in a single grinding operation. This improved material-removal process is made possible by controlling the grinding infeed to rates below 100 nanometers per grinding wheel revolution. This process adapts the ductile-regime, and even the new technology described above cannot completely eliminate surface fracture during the grinding of glass. It is proposed that by introducing a diamond polishing slurry between the grinding wheel and the workpiece, high precision optical-quality glass components could be produced for the first time with a single machining operation. An additional benefit resulting from the introduction of a polishing slurry into the grinding zone is that it will permit ultra-precision grinding of large (greater than 1 meter) optical components, an application that has previously been considered to be impossible because of the rapid dulling of the diamond grinding wheel in the machining of glass. In this application, the combined grinding/polishing approach has considerable merit: by continually dressing the wheel, the loose abrasive solves the problem of grinding wheel dulling. At the same time, the precise control of tool position offered by grinding overcomes the inherent contour inaccuracies that are encountered in polishing operations.