磨料水射流抛光技术研究进展 (特邀)

Significance The design of optical components featuring freeform surfaces and complex microstructures provides greater degrees of freedom, reduces their size, and significantly enhances the performance of optical systems. The surface quality and form accuracy of optical components directly influence the performance and lifespan of these systems. While complex curved optical components can be fabricated using ultra-precision turning, micro-milling, and grinding, the resulting surfaces often exhibit surface and subsurface damage that fails to meet practical requirements. Therefore, it is essential to employ post-processing polishing techniques to remove surface and subsurface damage, achieving nanometer-level surface roughness while maintaining form accuracy. Contact polishing methods, such as bonnet polishing, copying tool polishing, shear-thickening polishing, and magnetorheological polishing, exhibit limited conformability for complex surfaces. In contrast, abrasive water jet polishing, as a flexible non-contact polishing process, demonstrates excellent adaptability to complex geometries, achieving effective conformal polishing results. Furthermore, by optimizing polishing parameters, abrasive water jet polishing can attain nanometer-level surface roughness, presenting significant potential for ultra-precision machining of optical components. Therefore, gaining a comprehensive understanding of abrasive water jet polishing is crucial for advancing the development of the optical industry. Progress Abrasive water jet polishing utilizes high-pressure fluid to accelerate micro- and nano-sized abrasive particles, achieving material removal through the impact of these particles on the workpiece surface. To gain a deeper understanding of the multi-scale material removal mechanisms during the jet polishing process, researchers have conducted fluid dynamics simulations to study the flow characteristics of the jet. Additionally, by analyzing the forces acting on the abrasive particles within the flow field, it is possible to obtain their motion trajectories and dynamic information, such as impact velocity distribution, impact frequency distribution, and impact angle distribution. Furthermore, researchers have developed micro-scale material removal models. For ductile materials such as metals and alloys, polishing primarily occurs through plastic removal, while for brittle materials like tungsten carbide and single-crystal silicon, the removal mode introduces increased brittleness, which adversely affects surface quality and subsurface damage mitigation. Currently, abrasive water jet polishing is widely applied to various shapes of metal and glass materials. However, the introduction of impact craters and limitations in removal capabilities for different morphologies mean that the post-polishing surface quality is dependent on the initial surface condition of the workpiece and the polishing parameters. For instance, polishing of mold steel with sinusoidal microstructures has reduced the surface roughness (Sa) from 400-600 nm to 15-18 nm, while maintaining a form accuracy greater than 99.2%. In contrast, surface roughness after polishing single-point diamond-turned surfaces can reach approximately 1 nm. To enhance the efficiency of abrasive water jet polishing, various methods have been proposed, including multi-jet polishing, ultrasonic cavitation-assisted jet polishing, and submerged air-driven jet polishing. While these methods significantly improve polishing efficiency, they still exhibit shortcomings in enhancing surface quality. The use of active nano-silica and cerium oxide abrasives in place of traditional micron-sized abrasives can achieve sub-nanometer surface roughness. However, this approach significantly reduces polishing efficiency, limiting practical applications. To improve the polishing quality of brittle materials, researchers have proposed ultrasonic vibration-assisted water jet polishing to mitigate the effects of abrasive accumulation on material removal. Extensive research has been conducted over the past several decades. However, the development of high-end instruments demands superior surface quality, including sub-nanometer surface roughness and damage-free surfaces. To meet the growing requirements for ultra-precision optical components, greater efforts must be made to improve polishing performance in the future. Conclusions and Prospects This review comprehensively examines the current process performance and application prospects of abrasive water jet polishing, based on the latest research advancements. It addresses the technical bottlenecks of traditional methods by summarizing newly developed fluid jet polishing processes and related research progress. Additionally, it analyzes existing technical challenges and proposes potential research directions to enhance the efficient and precise machining of complex surfaces. Key areas for future efforts include achieving sub-nanometer surface roughness, improving the polishing quality of brittle materials through the integration of multiple physical fields, developing a more effective circulation system and high-performance pump, and implementing an intelligent control system. This review aims to provide valuable insights for relevant fields and promote the further development and practical application of abrasive water jet polishing technology.