When a surface experiencing robotic processing to improve its optical performance (such as removing mid-spatial frequencies, localized grinding errors, and regional surface scratches), spindle speed, tool travel speed, pressure, slurry density as well as groove patterns are main factors to influence surface finishes. Based on the desired material removal rate, the Preston equation can provide optimized pressures and velocities between the tool and processed surface. Various groove patterns, however, can hardly predict by the equation because different patterns can cause unique tool deformation and pressure distribution, leading to determine unique smoothing result. In this paper, four typical groove patterns are studied: non-groove, grid grove, annular groove and radial groove with three typical tool types are evaluated by Finite Element Method (FEM) and statistics. Characteristics of these tools and groove patterns are presented in the end of this paper.
We propose a sampling method to measure surface roughness of circular flat in this paper. The steps of this method are described in following. First, the number of sampling points is determined based on the radius of the circular flat; then the sampling points are selected by a certain angle in helical line; at last we use instrument like white light interferometer to measure the surface roughness of these sample points. The sampling method can effectively use the surface roughness of sampling points to estimate the surface roughness of the overall optical surface. According to mathematic derivation and simulation analysis, this method has a good sampling results, thus it can be widely used to measure the surface roughness of the circular flat.
Reducing the optical surface roughness is the key to improve the polishing quality of optical mirrors. Traditional
polishing technology in ultra-smooth polishing glass has been used widely for a long time. In this paper, the theories of
traditional polishing in polishing process were summarized. The problems in polishing procedure were analyzed and the
influence factors of optical surface roughness were provided according to the polishing procedure of optical mirrors, and
the relative measurements were pointed out. During the factors, polishing slurry and polishing pad are the important ones.
Contrasting with former traditional polishing technology, roughness factors of new polishing slurry and polishing pad
were analyzed and used in polishing process. The optical mirror of Ø246mm was polished in traditional technology with
new polishing slurry and polishing pad, the obtained testing results were surface roughness 3.421nm before polishing
and 0.613nm after polishing.
With the development of science and technology, the demand for high-precision product is increasing continuously. Ultra-smooth surface with sub-nanometer roughness has extensive applications in the field of soft X-ray optics, high power laser and laser gyro. Bowl feed polishing (BFP) technology is an effective ultra-smooth surface processing method, but the polishing process of BFP which is affected by a lot of factors is extremely complex and difficult to control. It is important to understand the effect of the process variables such as abrasive particle size, concentration of abrasive particle, speed of polishing pad, acidity and polishing time in the process of BFP. They are very important parameters that must be carefully formulated to achieve desired material removal rates and surface roughness. Using a design of experiment (DOE) approach, this study was performed investigating the main effect of the each parameter during K9 BFP. A better understanding of the interaction behavior between the various parameters and the effect on removal rate and surface roughness is achieved by using the statistical analysis techniques. In the experimental tests, the optimized parameters combination for BFP which were derived from the statistical analysis could be found for material removal rate and better surface roughness through the above experiment results.