A Real-Time Dressing Method for Metal Lapping Pads Based on the Thermal-Deformation Effect

Abstract

The surface shape and accuracy of the metal lapping pad are important factors that affect the performance of the lapping process for flat optical components. A real-time control system for metal-lapping-pad surface shape (RCLPS) based on the bimetal thermal-deformation effect is proposed. Unlike traditional dressing methods (e.g., turning dressing with a diamond tool), real-time dressing based on the RCLPS system is a material-loss-free and in-process dressing method. A full-aperture lapping turntable based on the RCLPS system was designed, and the working heat was analyzed. A thermal-deformation model was established through regression analysis. Finally, experiments were conducted to verify the functionality of the RCLPS system. During turning dressing (turntable rotational speed nm = 100 rpm), the thermal-deformation error caused by the working heat of the turntable-shaft system was compensated by the RCLPS system. During the lapping process for optical elements (nm ≤ 20 rpm), the real-time dressing of the lapping-pad surface shape was controlled by the coolant temperature of the RCLPS system, permitting optimization and adjustment of the process performance of the plane optical component. The effectiveness and practicality of the RCLPS system were demonstrated experimentally.