This representative result shows the post-finishing figure data for a 400 × 50 mm microcrystalline straightedge processed on the PKC500Q. The published result is 0.072 λ PV and 0.008 λ RMS. Because the reference wavelength was not disclosed, the values remain in waves and are not converted to nanometers. The case is primarily relevant to deterministic control of elongated, rectangular, and other non-circular optical apertures.
Item | Published Record |
Customer Requirement | Apply deterministic figure correction over an elongated 8:1 rectangular region and control edge/path coverage. |
Workpiece size | 400 × 50 mm microcrystalline straightedge; aspect ratio 8:1. |
Workpiece type | The record describes the workpiece as microcrystalline; exact material grade is not disclosed. |
Aspect ratio | 8:1 |
Final PV | 0.072 λ |
Final RMS | 0.008 λ |
Processing platform | PKC500-Q magnetorheological finishing machine |
Final Result | Retain 0.072 λ PV and 0.008 λ RMS exactly as published. Do not convert to nanometres without the base wavelength, and do not claim a reduction percentage without initial data. |
An elongated flat component differs from a conventional circular optic in both measurement and process planning. The high aspect ratio increases the importance of edge management, path coverage, uniform removal, and consistent mapping between the metrology data and machine coordinates. MRF uses a spatially varying dwell-time solution rather than uniform full-surface polishing, allowing localized correction across a rectangular aperture.
• Elongated non-circular aperture: The 400 × 50 mm, 8:1 geometry requires a data mask and path strategy matched to a rectangular active area.
• Edge effects: Removal-function truncation along the long edges and end regions must be considered in path planning.
• Full-length consistency: Stable removal and coordinate mapping must be maintained over the 400 mm length.
The PKC500-Q multi-axis platform and MRF software can process figure data for flats, spheres, aspheres, and freeforms. For an elongated straightedge, the central process tasks are to define the rectangular data aperture, map the removal function to the full length, solve the dwell-time distribution, and verify the residual figure using the same data convention.
1. Define the rectangular aperture: Establish the 400 × 50 mm data region, edge mask, and metrology coordinates.
2. Acquire the figure map: Map the elongated surface data into the machine coordinate system.
3. Plan removal and edge treatment: Match removal-function coverage and edge strategy to the selected polishing head.
4. Solve the dwell-time map: Allocate local dwell time along the long edges, end regions, and central area.
5. Polish and remeasure: Execute deterministic polishing and verify the final PV and RMS using the same processing rules.
The published final result is 0.072 λ PV and 0.008 λ RMS. Under the recorded workpiece and metrology conditions, this demonstrates precision figure correction over a 400 mm-long rectangular optical region. Because no initial figure map or processing time was disclosed, no improvement factor or productivity claim is calculated.
Published figure result: 0.072 λ PV and 0.008 λ RMS
• MRF processing of a 400 mm-class elongated rectangular aperture.
• Metrology-data mapping and dwell-time solution for a non-circular active area.
• Application potential for straightedges, elongated reference surfaces, and rectangular optics.
• Retention of wave-based values when the reference wavelength is not available.
• Precision optical straightedges
• Elongated mirrors or windows
• Rectangular reference surfaces
• Optics requiring non-circular aperture masks
Data and Metrology Note: The reference wavelength was not disclosed, so 0.072 λ and 0.008 λ cannot be converted reliably to nanometers. The material grade, initial figure, relationship between the data aperture and outer dimensions, metrology instrument, removed terms, filtering, polishing head, MRF fluid, cycle count, processing time, and measurement uncertainty were also not disclosed.
