Research on Optimized Design of In Situ Dynamic Variable-Aperture Device for Variable-Spot Ion Beam Figuring

Area of Science:

• Materials Science and Engineering
• Optical Engineering
• Nanotechnology

Background:

• Ion beam figuring (IBF) is a critical ultra-high-precision surface finishing technique.
• A key challenge in IBF is the trade-off between removal spot size and figuring accuracy.
• Existing variable-aperture tools have limitations in optimizing this trade-off.

Purpose of the Study:

• To design and validate an in situ dynamic beam variable-aperture device for IBF.
• To overcome the limitations of conventional IBF processing by enabling flexible spot size adjustment.
• To enhance the efficiency, flexibility, and accuracy of IBF.

Main Methods:

• Designed a novel in situ dynamic beam variable-aperture device.
• Optimized diaphragm sheet parameters and utilized focusing coil (FOC) for dynamic aperture control.
• Conducted simulations to assess removal function distortion and experimental validation of spot size adjustability and precision.

Main Results:

• Simulations indicated minimal removal function distortion (<5%) with optimized diaphragm sheets.
• FOC enabled rapid (≤0.45 s) and precise aperture control.
• Experiments demonstrated adjustable spot sizes (FWHM 0.7-17.2 mm) with high Gaussian correlation (>96.7%), stable parameters (≤5% change rate), and precise repeatability (≤3.2% change rate).

Conclusions:

• The developed dynamic beam variable-aperture device effectively addresses the IBF spot size trade-off.
• This technology enhances IBF processing efficiency, flexibility, and accuracy.
• It overcomes conventional limitations, paving the way for advanced ultra-high-precision surface finishing.