Investigation of Optimal Air-Driving Fluid Jet Polishing Parameters for the Surface Finish of N-BK7 Optical Glass

Abstract

The aim of this study is to investigate optimal air-driving fluid jet polishing (FJP) parameters by using Taguchi's method to improve surface roughness of N-BK7 optical glass on a machining center. An orthogonal array and the signal-to-noise (S/N) ratio are employed to determinate the optimal polishing parameters, and analysis of variance (ANOVA) is used to identify the main parameters that affect the surface roughness of the N-BK7 optical glass. An air-driving FJP tool is newly designed and fabricated to conduct experiments. To determinate the optimal air-driving FJP parameters, six polishing parameters, namely air pressure, impact angle, standoff distance, the abrasive material, abrasive concentration, and polishing time, are selected as the control factors of experiments. Based on the Taguchi's L18 orthogonal array experimental results and the S/N ratio, the optimal parameters for the N-BK7 optical glass are found. These optimal parameters are to be as follows: an air pressure of 0.490 MPa, an impact angle of 40 deg, a standoff distance of 12 mm, the abrasive material of Al2O3, an abrasive concentration of 10 wt. %, and a polishing time of 30 min. The surface roughness of specimen is improved from Ra = 0.350 μm–0.032 μm by using the optimal air-driving FJP parameters. In addition, the determined optimal polishing parameters for the plane surface are applied to the surface finish of an N-BK7 spherical lens, and the surface roughness of the spherical lens can be improved from Ra = 0.421 μm to 0.202 μm within an area of 283.6 μm × 200 μm.

Ultra-Precision Polishing of N-Bk7 Using an Innovative Self-Propelled Abrasive Fluid Multi-Jet Polishing Tool

“…Since then, various researchers have developed different polishing methods. For instance, Fahnle et al (1998) invented fluid jet polishing (FJP) and Huu Loc et al (2013) developed an air-driven fluid jet polishing mechanism.…”

Study of Gas Film Characteristics in Electrochemical Discharge Machining and Their Effects on Discharge Energy Distribution

“…Therefore, some nontraditional processing methods have been used, such as ultrasonic machining, laser beam machining, and abrasive flow machining. Nonetheless, nontraditional machining methods are ineffective in resolving problems such as microcracks in glass micromachining, thereby limiting their widespread use in this field [ 5 , 6 , 7 , 8 , 9 , 10 ]. In a previous study, a new composite machining method, electrochemical discharge machining (ECDM), was proposed to improve the processing quality.…”

Experimental investigation on modified air abrasive jet machining (MAAJM)

“…The jet direction is mainly affected parameter to get uniform MRR and they also introduced slip-scratch effect for better surface finish. Loc et al (2013) introduced a newly designed and fabricated air-driving fluid jet polishing machine for improving surface roughness on N-BK7 glass material by polishing process parameters namely SOD, impact angle, Air pressure, Time and abrasive concentration. The experiment runs are carried out using Taguchi's, technique to determine optimal process parameters combinations used are as follows: impact angle 40°, SOD 12 mm, Air pressure 0.49MPa, abrasive concentration 10 wt.%, Time 30 min these optimal values improved surface roughness from Ra = 0.35 µm-0.032 µm.…”