A high-speed precision micro-spindle use for mechanical micro-machining

Mechanical micro-machining has significant advantages in compassion with other machining techniques in terms of workpiece complexity, material diversity, energy consumption, and cost. The existing micro-spindles, as the key fundamental equipment, cannot simultaneously guarantee ultra-high rotational speed, high rotational accuracy, and compact structure. This study discussed the details in designing of high-speed precision micro-spindles, and a new micro-spindle was proposed, which is driven by an air turbine. To enhance its stiffness and rotational accuracy, the porous ceramic aerostatic bearings are used. The key structural parameters were selected based on theoretical calculation and simulation analysis. More importantly, the theoretical models for its static error and dynamic response predictions were established and combined to optimize the size of micro-spindle. The prototype micro-spindle has a radial motion error of approximately 6.0 μm and no heating problem. The micro-grinding experiment of micro-channel shows its good feasibility and potential application in mechanical micro-machining. And it has very simple and compact structure (28 mm in diameter × 45 mm in length) and low manufacturing difficulty and cost.