3D-soule: A fabrication process for large scale integration and micromachining of spherical structures

This paper reports a method for integrating and micromachining spherical structures made from materials such as fused quartz that are not amenable to melting or reflow. The 3D-SOULE process combines batch-mode micro ultrasonic machining (μUSM), lapping, and micro electro-discharge machining (μEDM) for creating spherical structures. Micro electro discharge machining is used for creating the stainless steel tool, which is then used for μUSM of the glass spheres. Stainless steel 440 which provides tool wear <;5% is used for μUSM. A machining rate of 24 μm/sec is achieved for fabrication of concave and mushroom-shaped spherical structures from 1 mm-diameter glass spheres.