Computer numerically controlled plasma chemical vaporization machining with a pipe electrode for optical fabrication

Abstract

We have developed a chemical vaporization machining device that has computer numerically controlled plasma, by using a pipe electrode for optical fabrications. In this device, less than approximately 1 atm of pressure, plasma is generated around the tip of a pipe electrode. During the process, a workpiece is scanned against the electrode under computer control to achieve the desired shape to be removed. A workpiece of silica glass plate is shaped by use of this device, and the removal characteristics of the device are examined. The equations to characterize numerically the shape resulting from scanning of a workpiece have been derived. The new device allows the high precision of optics from the micrometer to the nanometer level with high-speed removal. The shaped surface is sufficiently smooth to be suitable for optical use.

Figuring of elliptical hard X‐ray focusing mirror using 1‐dimensional numerically controlled local wet etching

“…The shape and the roughness of the mirror were measured by a phase shift laser interferometer (Zygo GPI-XP HR) and a microscopic interferometer (Zygo New View 200CHR), respectively. The material, size of the substrate and shape-evaluated area on the substrate were singleside-polished synthesized quartz glass, 100 × 50 × 15 mm 3 and 84 × 36 mm 2 , respectively. In that case, we applied raster scanning (feed pitch : 0.4 mm) using a circular nozzle to correct the figure error, and other machining parameters as shown in Table 1.…”

Creation of perfect surfaces

“…PCVM [5][6][7][8][9] utilizes highly reactive neutral radicals (such as halogen atoms with high electronegativity) generated in a high-pressure very high frequency (VHF) plasma. The generated radicals react with the surface atoms of the workpiece and transform them into volatile molecules.…”

The experimental study of super-smooth surface processing technology for optical glass and sapphire component

“…There are many different types of super smooth processing technology currently, Such as Bowl Feed Polish (BFP), 4 Elastic Emission Machining (EEM), 5 Flow Polishing, 6 Plasma Assisted Chemical Etching (PACE), 7 Plasma Chemical Vaporization Machining (CVM), 8 Hydroplane Polishing, 9 Magnetic Field Finishing (MFF), 10 Magnetic Abrasive Finishing (MAF), 11 Magnetic Fluid Polishing (MFP), 12 Magnetorheological Finishing (MRF) 13 and etc. It's difficult to explain the mechanism of super smooth processing technology with just only one theory.…”