Infrared and Laser Engineering, Volume. 54, Issue 3, 20240514(2025)
Strategies for correction of centrifugal deformation error in single-point diamond turning
ObjectiveDue to the high rotational speed, aluminium alloy mirrors are centrifugally deformed during single-point diamond turning (SPDT) machining, resulting in mirror surfaces not meeting the stringent accuracy specifications required for optical systems in the visible spectrum. The core of centrifugal deformation suppression is to solve the problem of mirror deformation caused by centrifugal force during processing. The purpose of this study is to ensure that the mirror has higher surface shape accuracy by suppressing centrifugal deformation, so as to improve the imaging quality of the optical system and make the image clearer and more accurate.
MethodsTo mitigate this issue, a computational simulation was conducted to quantify and characterize the centrifugal deformational errors present on the reflector surface under conditions of elevated rotational speeds. Additionally, an in-depth analysis was performed to elucidate the impact of centrifugal deformation on the mirror surface fabrication. A corrective approach for centrifugal deformational errors was developed, encompassing advanced fixturing techniques for the mirror body and path optimization algorithms for trajectory correction. An experimental study was carried out on a 300 mm aperture aluminum alloy reflector to benchmark the machining precision.
Results and DiscussionsA clamping process considering centrifugal deformation error compensation was designed to ensure the rotational symmetry of the mirror deformation (Fig.5). According to the turning process of the rotary symmetrical parts (Fig.6), a trajectory generation method to correct the centrifugal deformation error was designed (Fig.7) .Test reflector achieved a peak-to-valley (PV) value of 0.604
λ and a root mean square (RMS) value of 0.084
λ (Fig.8), representing a significant improvement of 56.02% and 58.88% reduction in RMS and PV, respectively, over conventional machining protocols.
ConclusionsThis research validates the efficacy of the proposed corrective strategy in managing centrifugal deformational geometry and effectuating precise error rectification, thereby offering a robust theoretical framework and technical innovation for the high-precision machining of optical reflectors. This research helps to optimise the single-point turning process, reduce production costs, and increase production efficiency. Finally, by effectively inhibiting centrifugal deformation, it can provide technical support for the development of China's optical manufacturing industry and promote the application of optical products in high-end fields such as aerospace and precision instruments.