Development of a High-Speed Precision Ultrasonic-Assisted Spindle for Ultra-Precision Optical Mold Machining

Ultrasonic vibration-assisted grinding is a critical method for machining ultra-hard optical molds. However, current ultrasonic-assisted grinding spindles, as essential foundational equipment, face limitations in maintaining ultra-high rotational speed, high precision, and a compact structure during ultrasonic operation. This study presents a novel ultra-precision ultrasonic-assisted high-speed aerostatic spindle for grinding ultra-hard optical molds, developed through theoretical calculations, FEM, and CFD simulations. The spindle features a simple and compact design (φ60 mm outer diameter × 194 mm length), operates at an ultrasonic frequency of 41.23 kHz, and is driven by an impulse turbine providing torque up to 50.4 N•mm, achieving speeds exceeding 40,000 r/min. Aerostatic bearings provide axial and radial load capacities of 89 N and 220 N, respectively. The results demonstrate that the proposed high-speed precision ultrasonic spindle exhibits both feasibility and potential for practical application.