Super-smooth finishing of diamond turned hard X-ray molding dies by combined fluid jet and bonnet polishing

Beaucamp, Anthony; Namba, Yoshiharu

doi:10.1016/j.cirp.2013.03.010

Cited by 160 publications

(34 citation statements)

References 9 publications

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“…Different shapes of mirrors such as flat, cylindrical, aspheric and ellipsoidal are generally used for focusing of X-rays. The advantages of mirrors include high beam throughput and no chromatic aberration compared to other focusing optics such as zone plates [3].…”

Section: Introductionmentioning

confidence: 99%

Single point diamond turning of silicon for flat X-rays mirrors

Khatri¹,

Sharma²,

Mishra³

et al. 2021

Advanced Materials Proceedings

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Silicon Mirrors are essential components for guiding the X-Ray beam and focusing it to a particular location. Due to lower X-ray wavelength, these mirrors require super smooth surface finish to avoid the strong scattering from surface. Single Point Diamond Turning is used to examine the fabrication possibility of X-Ray mirror. A number of machining cuts are performed with parameters like tool feed rate, Spindle Speed and depth of cut. The surface is characterized by mechanical profiler, optical profiler, Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The optimized surface roughness achieved is 0.873 nm.

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Section: Introductionmentioning

confidence: 99%

Single point diamond turning of silicon for flat X-rays mirrors

Khatri¹,

Sharma²,

Mishra³

et al. 2021

Advanced Materials Proceedings

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“…It possesses a number of merits including: 1) absence of tool wear and edge effect due to the non-contact removal mechanism, 2) ability to generate submillimeter removal footprint that adapt to complex surfaces. Owing to these advantages, super fine finish without residual tool marks can be achieved when post-processing diamond turned surfaces such as X-ray molding dies [10]. Nonetheless, this technology could bring higher added-value in industry if it could be applied to direct fabrication of freeform optical surfaces with ultraprecise form error (peak-to-valley < 100 nm) in a fully automated and deterministic manner, rather than mere post-polishing.…”

Section: Introductionmentioning

confidence: 99%

Zernike mapping of optimum dwell time in deterministic fabrication of freeform optics

Zhu

Beaucamp

2019

Opt. Express

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In optics fabrication technologies such as computer controlled optical surfacing (CCOS), accurate computation of the dwell time map plays an essential role in the deterministic performance of the fabrication process. However, it is still difficult for existing methods to derive smooth dwell time maps that reduce dynamic stressing on the machine especially at the aperture edge region, while retaining fine correction capability on freeform optics. To answer these challenges, we propose a new method based on Zernike decomposition and improved differential evolution optimization of the dwell time map, which can be applied to time-dependent optics fabrication processes such as fluid jet machining. Simulations and experiments based on a bisinusoidal freeform design were carried out to assess the feasibility of the proposed methodology. With appropriate fluid jet pressure, a bi-sinusoidal optical surface with demanding form error target of sub-100 nm in peak-to-valley was achieved, showing a remarkable improvement on the state-of-the-art, while keeping a good average surface roughness of 2.6 nm Ra on the optical glass.

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“…In recent years, with the development of a series of advanced non-traditional sub-aperture CCOS polishing technologies such as bonnet polishing [6], fluid jet polishing [7], magnetorheological polishing [8], ion beam polishing [9], laser polishing [10], etc., the controllability of deterministic polishing has taken a new step, which provides more possibilities for the improvement of the correction effect of the surface form error. Among them, fluid jet polishing is an ultra-precise finishing technology that combines fluid mechanics, precision manufacturing and surface engineering.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of Path Adaptability Based on Surface Form Error Distribution in Fluid Jet Polishing

et al. 2018

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In the technology of computer-controlled optical surfacing (CCOS), the convergence of surface form error has a close relationship with the distribution of surface form error, the calculation of dwell time, tool influence function (TIF) and path planning. The distribution of surface form error directly reflects the difference in bulk material removal depth across a to-be-polished surface in subsequent corrective polishing. In this paper, the effect of path spacing and bulk material removal depth on the residual error have been deeply investigated based on basic simulation experiments excluding the interference factors in the actual polishing process. With the relationship among the critical evaluation parameters of the residual error (root-mean-square (RMS) and peak-to-valley (PV)), the path spacing and bulk material removal depth are mathematically characterized by the proposed RMS and PV maps, respectively. Moreover, a variable pitch path self-planning strategy based on the distribution of surface form error is proposed to optimize the residual error distribution. In the proposed strategy, the influence of different bulk material removal depths caused by the distribution of surface form error on residual error is compensated by fine adjustment of the path spacing according to the obtained path spacing optimization models. The simulated experimental results demonstrate that the residual error optimization strategy proposed in this paper can significantly optimize the overall residual error distribution without compromising the convergence speed. The optimized residual error distribution obtained in sub-regions of the polished surface is more uniform than that without optimization and is almost unaffected by the distribution of parent surface form error.

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Super-smooth finishing of diamond turned hard X-ray molding dies by combined fluid jet and bonnet polishing

Cited by 160 publications

References 9 publications

Single point diamond turning of silicon for flat X-rays mirrors

Single point diamond turning of silicon for flat X-rays mirrors

Zernike mapping of optimum dwell time in deterministic fabrication of freeform optics

Theoretical Study of Path Adaptability Based on Surface Form Error Distribution in Fluid Jet Polishing

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