Mid-spatial frequency errors suppression strategy in micro-variable offset bonnet polishing based on direction...

Area of Science:

• Optical engineering
• Precision manufacturing
• Surface metrology

Background:

• Bonnet polishing, a common sub-aperture technique, often introduces mid-spatial frequency (MSF) errors.
• These MSF errors degrade optical component surface accuracy and system imaging quality.

Purpose of the Study:

• To propose and validate a strategy for suppressing MSF errors in micro-variable offset bonnet polishing.
• To achieve enhanced surface figure accuracy for optical components through process optimization.

Main Methods:

• Synergistically optimizing direction angle and path step to mitigate MSF error generation.
• Establishing a quantitative model linking tool influence function (TIF) parameters to frequency domain error distribution.
• Introducing random offset perturbations at dwell points to disrupt TIF spatial coherence and MSF error periodicity.

Main Results:

• Optimized direction angle and path step significantly reduced MSF error amplitude.
• Root mean square (RMS) MSF error reduced from 1.119 nm to 0.529 nm (52.7% reduction).
• Further reduction to 0.389 nm RMS (65.2% reduction) achieved with random perturbations.

Conclusions:

• The proposed strategy effectively suppresses MSF errors in bonnet polishing through process parameter optimization.
• This method offers a practical and feasible approach for manufacturing high-precision optical components without complex path planning.