Loose abrasive grinding of optical surfaces

Area of Science:

• Materials Science
• Manufacturing Engineering
• Surface Metrology

Background:

• Loose abrasive lapping is a precision finishing process used to achieve smooth surfaces.
• Controlling the final surface shape, particularly sphericity, is critical for optical and mechanical components.
• Understanding the influence of process parameters on surface topography is essential for optimizing lapping outcomes.

Purpose of the Study:

• To identify key working parameters governing surface shape evolution during loose abrasive lapping.
• To investigate methods for reducing the complexity of radius changes in the lapping process.
• To quantify the deviation from spherical shape produced by loose abrasive lapping.

Main Methods:

• Experimental investigation of surface shape development during lapping.
• Interferometric analysis to measure deviations from spherical shape.
• Systematic variation of working parameters to study their effects.

Main Results:

• The study identified specific working parameters that influence surface shape during lapping.
• It was found that appropriate parameter selection can simplify the process and reduce radius variations.
• Interferometric measurements showed that while nonspherical surfaces are common, deviations can be minimized to less than 1/10 of a wavelength under optimized conditions.

Conclusions:

• Working parameters significantly impact the surface shape generated by loose abrasive lapping.
• Proper selection of these parameters can lead to a more controlled and predictable lapping process.
• Minimizing surface form errors, specifically departure from sphericity, is achievable through careful process control.