Nano-metric Polishing of Optical Lenses by Magnetic Float Polishing (MFP)

Polishing of surfaces by Magnetic Float Polishing, is a non-traditional method of machining. This article aims to study polishing of spherical lenses by magnetic float polishing (MFP). Principle of this method is based on magneto- hydrodynamic behavior ofmagnetic fluid. Optical lenses which are used in military industry are themost important parts polished by MFP. Because of the Military Binoculars and military camera in the Drones it’s important that optical lenses used in them, should have a high level of roughness possible. By this method, it is possible to polish such surfaces up to nanometer scales, which traditional methods can not satisfy such precision. Amount of mixing the abrasives in a magnetic fluid, abrasives size, spindle speed and process time are studied in this investigation. At this study, a device was designed and manufactured and transparency and the roughness obtained are two features of the process that has been studied. After designing and applying of MFP, the experiments carried out on it and its results have been analyzed. Finally, after analyzing and optimizing the factors in MFP process experimentally and statistically, a roughness ofRz= 14nm has been obtained and it’s found that by increasing of the spindle speed and amount of mixing the abrasives in a magnetic fluid and abrasives size, the roughness will be improved at least 10 percent. By Using the MFP for spherical lenses, polishing process is not related to their core radius and it makes the cost savings and speed to be paid. Effective parameters and the regression equations governing the process are also determined.