Freeform surface machining error compensation method for ultra-precision slow tool servo diamond turning

Chen, Chun‐Chieh; Huang, Chien-Yao; Peng, Wei-Jei; Cheng, Yung‐Chen; Yu, Zong-Ru; Hsu, Wei-Yao

doi:10.1117/12.2022981

Cited by 13 publications

(5 citation statements)

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“…Therefore, the focal length of relay lens in horizontal and vertical direction is equal, as shown in Eq. (7). Where H p is the height of the panel, H LA is the height of the lenslet, f R is the focal length of relay lens, f LA is the focal length of the lenslet, f R-x is the focal length of relay lens in horizontal direction, f R-y is the focal length of relay lens in vertical direction, L P is the length of the panel, W p is the width of the panel, L LA is the length of the lenslet, and W LA is the width of the lenslet.…”

Section: Mla System Designmentioning

confidence: 97%

Freeform mirror for illumination system of color-sequential LCOS pico projector

Peng¹,

Chen²,

Huang³

et al. 2014

SPIE Proceedings

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This paper proposes an efficient and uniform illumination system with a freeform mirror for a color-sequential LCOS pico projector based on LED. The novel homogenizer is composed of a micro lens array and a freeform mirror. A freeform mirror with XY polynomial profile is adopted for the reshaping of light pattern, the correction of keystone distortion and the folding mirror for the reduction of volume. Typically, the design of micro lens array, the aspect ratio of the lenslet is corresponding with that of the panel. However, the crosstalk phenomenon occurs due to each lenslet with different collecting angle in horizontal and vertical direction, especially when the aspect ratio of the panel in our study is 16:9. The crosstalk phenomenon not only reduces efficiency but also generates stray light on the panel. Therefore, we use a micro lens array with square lenslet to eliminate it. Subsequently, the square light pattern on the panel needs to be reshaped to fit the aspect ratio of the panel. A cylindrical mirror with a fixed power is used to compress the light pattern first. However, for the requirement of different focal distances from the cylindrical mirror to the panel on entire surface, it generates severe keystone distortion. A freeform mirror with progressive power variation is employed for the correction of keystone distortion with high overfilled efficiency and the reshaping of the light pattern fitting the ratio of the panel. In the results of optical simulation, JBMA uniformity on the panel is 98 % and the coupling efficiency from LED to the plane of the panel is 85 %. Furthermore, the alignment tolerance of the freeform mirror has also been discussed. Finally, the freeform mirror is fabricated by ultra-precision diamond milling process. The form accuracy and surface roughness of the freeform mirror are less than 0.5 um and 5 nm, respectively.

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Section: Mla System Designmentioning

confidence: 97%

Freeform mirror for illumination system of color-sequential LCOS pico projector

Peng¹,

Chen²,

Huang³

et al. 2014

SPIE Proceedings

Self Cite

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“…Researchers mostly explore FTS machining for lenslet array due to the flexibility and less cycle time (Yu et al, 2011;Zhu et al, 2017). Compared to FTS, no extra setup is required in STS machining; however, it consumes a lot of time in fabrication due to the lower spindle speeds (Chen et al, 2013;Li et al, 2019;Mukaida et al, 2017). The researchers show much interest in MLA due to its excellent imaging performance by eliminating aberration and increasing the Field of View (FoV).…”

Section: Fabrication Of Znse Mlamentioning

confidence: 99%

Optical design and fabrication of zinc selenide microlens array with extended depth of focus for biomedical imaging

Khatri

Berwal

Manjunath

et al. 2023

Nanofab

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Optical coherence tomography is a well-known technique for the optical imaging biological tissues. However, the depth scanning range of high-resolution optical coherence tomography is restricted by its depth of focus. In this study, a Zinc Selenide (ZnSe) Microlens Array (MLA) is employed to overcome the depth-of-focus limitation of optical coherence tomography. The ZnSe material with a low Abbe number and high chromatic dispersion extends the depth of focus with transverse resolution. The ZnSe MLA focused the incident light (from visible to near-infrared (NIR) region) on multiple focal planes with the uniform distribution of light over a biological tissue. The MLA is designed using Zemax OpticStudio software and fabricated via a single-point diamond-turning based on Slow Tool Servo (STS) configuration. STS machining has the unique advantage of offering larger degrees of freedom with no additional baggage, thereby reducing the setup time. The experimental results show the effectiveness of the STS machining process in fabricating ZnSe MLA with desired accuracies. The characterization of fabricated MLA using Coherence Correlation Interferometry (CCI) depicts uniform lenslets with no structural and positional distortion, with a total error of 32 nm within the tolerance limit.

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“…The STS methodology facilitates a synchronised interplay between slide and spindle movements in diamond turning machines, thereby enabling the generation of freeform surfaces without the necessity for supplementary tool axes [18,19]. Nonetheless, there exists a pressing requirement to enhance the dynamics governing these motions.…”

Section: Dynamic Effects In Ultraprecision Machining With Slow Tool S...mentioning

confidence: 99%

Determinant of Dynamics and Interfacial Forces in Ultraprecision Machining of Optical Freeform Surface through Simulation-Based Analysis

Khaghani,

Ivanov,

Cheng

2023

Micromachines

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This study delves into the intricacies of ultraprecision machining, particularly in the context of machining optical freeform surfaces using Diamond Turning Machines (DTMs). It underscores the dynamic relationship between toolpath generation, hydrostatic bearing in DTMs, and the machining process. Central to this research is the innovative introduction of Metal Matrix Composites (MMCs) to replace the traditional materials used in designing linear bearings. This strategic substitution aims to dynamically enhance both the accuracy and the quality of the machined optical freeform surfaces. The study employs simulation-based analysis using ADAMS to investigate the interfacial cutting forces at the tooltip and workpiece surface and their impacts on the machining process. Through simulations of STS mode ultraprecision machining, the interfacial cutting forces and their relationship with changes in surface curvatures are examined. The results demonstrate that the use of MMC material leads to a significant reduction in toolpath pressure, highlighting the potential benefits of employing lightweight materials in improving the dynamic performance of the system. Additionally, the analysis of slideway joints reveals the direct influence of interfacial cutting forces on the linear slideways, emphasising the importance of understanding and controlling these forces for achieving higher-precision positioning and motion control. The comparative analysis between steel and MMC materials provides valuable insights into the effects of material properties on the system’s dynamic performance. These findings contribute to the existing body of knowledge and suggest a potential shift towards more advanced precision forms, possibly extending to pico-engineering in future systems. Ultimately, this research establishes a new standard in the field, emphasising the importance of system dynamics and interfacial forces in the evolution of precision manufacturing technologies.

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Freeform surface machining error compensation method for ultra-precision slow tool servo diamond turning

Cited by 13 publications

References 0 publications

Freeform mirror for illumination system of color-sequential LCOS pico projector

Freeform mirror for illumination system of color-sequential LCOS pico projector

Optical design and fabrication of zinc selenide microlens array with extended depth of focus for biomedical imaging

Determinant of Dynamics and Interfacial Forces in Ultraprecision Machining of Optical Freeform Surface through Simulation-Based Analysis

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