Trends in Ultra-Precision Machining of Freeform Optical Surfaces

Tohme, Yazid E.

doi:10.1364/oft.2008.othc6

Cited by 14 publications

(8 citation statements)

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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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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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“…Compared with the traditional bifocal lenses and trifocal lenses, the PAL lens could provide the dioptre continuous variation through the progressive zone between far zone and near zone, which is achieved by continuously change of curvature radius, so as to solve the problem of vision jump drawback [2] , as shown in figure 1. Because the progressive addition lens is a freeform surface with variable radius of curvature, complex geometry, the traditional processing methods are difficult to achieve the designed requirements.…”

Section: Introductionmentioning

confidence: 99%

Study on optical freeform surface manufacturing of progressive addition lens based on fast tool servo

Cai

Xiao³

et al. 2017

IOP Conf. Ser.: Earth Environ. Sci.

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Abstract. Progressive addition lens (PAL) is currently the state-of-the-art in multifocal correction visual for freeform lens. The PAL is used to correct presbyopia by the distributing optical powers of the three zones, which are far zone, near zone and intermediate zone. As the dioptre of progressive zone varies continuously, the lenses realize simultaneously far view and near view by a pair of glasses. Because the PAL is a freeform surface with a variable radius of curvature, complex shape, processing difficulties, low efficiency, big fluctuation of interpolation error and so on. In this paper, the design surface is discretized by the constant angle method and compensates the path of the diamond tool nose radius with AKIMA interpolation method, which can identify the machine tool of the tool locus, and exploitable fast tool servo technology controls the diamond tools movement and path. MATLAB simulation results show that this method is generally more approximate to the ideal trajectory, which is not only to ensure that surface profile accuracy, but also meet the requirements of the processing efficiency and better control the surface profile.

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“…The traditional Z-axis cannot move fast enough to follow the cutting trajectory required for machining the freeform surfaces in a diamond turning machine. Although the slow slide servo with its range of several millimeters has been used to fabricate the optical freeform surfaces, its bandwidth is limited because of its large mass in Z-axis [5]. Therefore, the FTS which has a high bandwidth and enough range for the tool motion can be a good candidate for machining freeform surfaces.…”

Section: Introductionmentioning

confidence: 99%

Design and Control of a Novel Fast Tool Servo Used in Diamond Turning of Freeform Optics

Tian

Yin

2016

KEM

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Optical free-form surfaces are becoming more and more popular in the industry application, which can be fabricated by diamond turning based on fast tool servo (FTS). It is an efficient, precise and low-cost processing method. In order to use diamond turning to fabricate the freeform optics, this paper develops a novel long range fast tool servo which is actuated by voice coil motor. The total range can reach up to 30 mm. The important parts of the FTS have been simulated and analyzed. The transfer function model identification of the FTS has been accomplished. Since the desired tool trajectories are approximately periodic signals in freeform surfaces turning, and the adaptive feedforward cancellation (AFC) control can achieve perfect tracking and disturbance rejection of periodic signals, the AFC control is designed to be added on the IMC-PID controller.

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Trends in Ultra-Precision Machining of Freeform Optical Surfaces

Cited by 14 publications

References 0 publications

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

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

Study on optical freeform surface manufacturing of progressive addition lens based on fast tool servo

Design and Control of a Novel Fast Tool Servo Used in Diamond Turning of Freeform Optics

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