Optimized tool path generation for fast tool servo diamond turning of micro-structured surfaces

Slow tool servo (STS) diamond turning is a well-developed technique for freeform optics machining. Due to low machining efficiency, fluctuations in side-feeding motion and redundant control points for large aperture optics, this paper reports a novel adaptive tool path generation (ATPG) for STS diamond turning. In ATPG, the sampling intervals both in feeding and cutting direction are independently controlled according to interpolation error and cutting residual tolerance. A smooth curve is approximated to the side-feeding motion for reducing the fluctuations in feeding direction. Comparison of surface generation of typical freeform surfaces with ATPG and commercial software DiffSys is conducted both theoretically and experimentally. The result demonstrates that the ATPG can effectively reduce the volume of control points, decrease the vibration of side-feeding motion and improve machining efficiency while surface quality is well maintained for large aperture freeform optics.

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Tool path generation of ultra-precision diamond turning: A state-of-the-art review

Nanotechnology and Precision Engineering ◽

10.1016/j.npe.2019.10.003 ◽

2019 ◽

Vol 2 (3) ◽

pp. 118-124 ◽

Cited By ~ 5

Author(s):

Hu Gong ◽

Shengjun Ao ◽

Kuntao Huang ◽

Yi Wang ◽

Changya Yan

Keyword(s):

Tool Path ◽

State Of The Art ◽

Tool Path Generation ◽

Diamond Turning ◽

Path Generation ◽

Ultra Precision

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Research on tool path generation for integrated off-axis four-mirror group in single point diamond turning

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/784/1/012016 ◽

2020 ◽

Vol 784 ◽

pp. 012016

Author(s):

Peixing Ning ◽

Ji Zhao ◽

Shijun Ji ◽

Jingjin Li ◽

Handa Dai

Keyword(s):

Tool Path ◽

Single Point ◽

Tool Path Generation ◽

Diamond Turning ◽

Path Generation ◽

Mirror Group

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A tool path generation method for quasi-intermittent vibration assisted swing cutting

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/0954408920935362 ◽

2020 ◽

Vol 234 (6) ◽

pp. 624-633

Author(s):

Zhimin Zhu ◽

Mingming Lu ◽

Jieqiong Lin ◽

Jiakang Zhou ◽

Allen Yi ◽

...

Keyword(s):

Tool Path ◽

Spline Interpolation ◽

Interpolation Theorem ◽

Tool Path Generation ◽

Diamond Turning ◽

Tool Geometry ◽

Machining Accuracy ◽

Path Generation ◽

Freeform Surfaces ◽

Tool Trajectory

During the machining of freeform surfaces, the tool path will directly affect the machining accuracy of the surface, the execution of each axis of the machine tool, and the machining efficiency. Therefore, tool path planning is a very critical link in all types of diamond turning processes. In this paper, a new tool path generation strategy is proposed for machining freeform surfaces by quasi-intermittent vibration assisted swing cutting (QVASC) method. Due to the unique tool swing motion law of QVASC, the effective central angle of tool nose arc participating in the cutting is a parameter that is ignored by traditional cutting and is considered. This makes the generation of tool trajectories, tool geometry selection and freeform surfaces very different from traditional diamond cutting. According to the principle of QVASC, the tool parameters are analysed, and the tool position is designed in the cylindrical coordinate system. Interpolation was then performed by the Hermite spline interpolation theorem. The application of this strategy is discussed, and the sinusoidal surface, sinusoidal mesh surface and toric surface are taken as examples to simulate. The simulation succeeded in obtaining the tool path corresponding to the three curved surfaces processed by the QVASC method. The results prove that the tool trajectory generation strategy proposed in this paper is feasible. The proposed tool path generation strategy can provide a new reference for future freeform surfaces processing.

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Study on Design and Diamond Turning of Optical Freeform Surface for Progressive Addition Lenses

Mathematical Problems in Engineering ◽

10.1155/2020/2850606 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Yi Wei ◽

Peng Zhai ◽

Xiaoyi Chen ◽

Lei He

Keyword(s):

Tool Path ◽

Single Point ◽

Optical Design ◽

Tool Path Generation ◽

Diamond Turning ◽

Freeform Surface ◽

Path Generation ◽

Nose Radius ◽

Angle Method ◽

Progressive Addition Lens

Optical freeform surface components have attracted much attention due to their high degree of design freedom and small size. However, the design and processing difficulty of such components limit its wide application in optics industry. In recent years, diamond turning has been considered an efficient method for processing optical freeform surfaces, but the research on tool path generation of this processing method is not systematic. Progressive addition lens (PAL) is a typical optical freeform surface and is widely used to correct people’s vision problems. Firstly, this paper introduces a method of designing PAL. Then, an optimized tool path generation method for diamond turning of the optical freeform surface is proposed, the equal angle method is used to select the discrete points, and a tool nose radius compensation method suitable for both slow slide servo (SSS) and fast tool servo (FTS) is adopted. Finally, the turning experiment is carried out with a single point diamond lathe, and a PAL surface with a roughness of 0.087 μm was obtained. The power and astigmatism distributions were measured using a Rotlex freeform verifier to verify the rationality of the optical design.

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Analysis of a novel tool path generation method for corrective machining in ultra-precision diamond turning based on point clouds

10.21203/rs.3.rs-964315/v1 ◽

2021 ◽

Author(s):

Marco Buhmann ◽

Erich Carelli ◽

Christian Egger ◽

Klaus Frick

Keyword(s):

Point Cloud ◽

Tool Path ◽

Cutting Tool ◽

Measurement Data ◽

Tool Path Generation ◽

Diamond Turning ◽

Surface Measurement ◽

Computation Method ◽

Path Generation ◽

Ultra Precision

Abstract The increasing demand for machining non-rotational optical surfaces requires capable and flexible cutting tool path generation methods for ultra-precision diamond turning. Furthermore, the recent interest in on-machine metrology and corrective machining require efficient as well as accurate algorithms capable to handle point cloud based surface data. In the present work, a new computation method for the tool path generation is proposed that focuses on three-axes corrective machining. Therefore, it is based on the principle of defining the surface to be machined by a point cloud of certain density, since surface measurement data is usually available as point cloud. Numeric approximation techniques are used to compute the surface normal vectors and calculate the resulting positions of the cutting tool path preserving a uniform radial axis motion for face turning. Investigations are performed in order to quantify the error between the calculated tool path and the exact analytical solution. The error dependencies are analyzed regarding the local surface slope and numerical parameters. Error values below 1nm are achieved. In addition, form deviation results prove the method’s capability for corrective diamond turn machining.

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