Microcomputer-controlled polishing machine for very smooth and deep aspherical surfaces

Area of Science:

• Materials Science
• Optical Engineering
• Manufacturing Technology

Background:

• Fabricating highly curved, aspherical components from anisotropic crystalline materials like lithium niobate presents significant manufacturing challenges.
• Achieving extremely smooth, low-damage surfaces is critical for high-performance optical applications.
• Existing computer numerical control (CNC) machining and polishing methods are inadequate for these demanding specifications.

Purpose of the Study:

• To develop a novel polishing method for fabricating small, highly curved, and aspherical lithium niobate components.
• To achieve exceptionally smooth and low-damage surfaces on these challenging optical elements.
• To overcome the limitations of conventional machining and polishing techniques for anisotropic materials.

Main Methods:

• Diamond-turning was employed for initial profile generation, but resulted in unacceptable surface roughness.
• A new, custom-built polishing machine was developed, featuring microcomputer control of three axes.
• A small rotating polishing tool was precisely navigated over the rotating aspherical component surface.
• Advanced tool path control algorithms were implemented for uniform material removal and precise surface correction.

Main Results:

• The novel polishing machine successfully produced highly curved, aspherical lithium niobate components.
• Achieved surfaces exhibited significantly improved smoothness and reduced subsurface damage compared to diamond-turning alone.
• The microcomputer-controlled system demonstrated precise control over material removal and surface metrology.

Conclusions:

• The developed microcomputer-controlled polishing machine is effective for fabricating demanding optical components from lithium niobate.
• This advanced manufacturing approach enables the production of ultra-smooth, low-damage surfaces on complex aspherical optics.
• The technology offers a viable solution for precision manufacturing of advanced optical materials with anisotropic properties.