Tool path optimal design for slow tool servo turning of complex optical surface

Chen, Xu; Kang, Min; Wang, Xinsheng; Hassan, Muhammad; Yang, Jun

doi:10.1177/0954405416654192

Cited by 12 publications

(7 citation statements)

References 16 publications

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“…For successful ultraprecision machining using STS methodology, the tool geometries play a significant role. 14 The tool feature selection is associated directly to the freeform surfaces topology such as curvature and sag element. As shown in Figure 1, typical diamond cutting tool geometrical parameters include the tool nose radius, Rake angle, diamond height, included angle and clearance angle.…”

Section: Slow Tool Servo and Dynamic Effectsmentioning

confidence: 99%

Investigation on multi-body dynamics based approach to the toolpath generation for ultraprecision machining of freeform surfaces

Khaghani

Cheng

2019

Proceedings of the Institution of Mechanical Engineers, Part B:

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This article presents an innovative approach to toolpath generation for ultraprecision machining of freeform optic surfaces based on the principle of Automatic Dynamics Analysis of Mechanical Systems. As components with freeform surfaces often have non-rotational symmetry, there are potential challenges facing their ultraprecision machining through single-point diamond turning, such as the projected points in complex large sag surfaces, which likely find it difficult to communicate with the control system and, thus, do not perform successfully. In ultraprecision machining, to achieve the highest performance in freeform surface resolution, the factors of dynamics, material and mechanical stiffness, frictions, tooling and accuracy of the servo component should be considered. The investigation is focused on an integrated approach and the associated scientific understanding of precision engineering design, ultraprecision machining and metrology of freeform surfaces as well as their application perspective. In this approach, the toolpath for very complex freeform surfaces can be generated using the Newton–Raphson method to solve the kinematics and dynamics equations of motion. The effect of friction and contact force are also investigated for accurate toolpath curve generation. Moreover, the Gear stiff (GSTIFF)/ Wielenga stiff (WSTIFF) integrator for solving the non-linear equations of motion is employed, and the result shows the time step size, playing a critical role in generating toolpath curves with a higher accuracy and resolution.

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Section: Slow Tool Servo and Dynamic Effectsmentioning

confidence: 99%

Investigation on multi-body dynamics based approach to the toolpath generation for ultraprecision machining of freeform surfaces

Khaghani

Cheng

2019

Proceedings of the Institution of Mechanical Engineers, Part B:

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“…Figure 8 shows the representation of PVT interpolation. The traditional algorithms for generating the entrance parameters of PVT, such as area method or three-point method, 25 could only ensure that the speed in each cutting tool location point is continuous, but the acceleration at each point is not completely continuous and the interpolation error will increase. So, a new algorithm called triangle rotary method is proposed to overcome the disadvantage, and this method transformed the segment Hermite interpolation into segment spline interpolation resulting in the acquisition of continuous acceleration and smaller interpolation error.…”

Section: Tool Path Generation For Sts Turning Of Pal Surfacementioning

confidence: 99%

Study on the variational-difference-based design and slow tool servo turning of progressive addition lenses

Kang

Yang

Wang

et al. 2018

Advances in Mechanical Engineering

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Nowadays, progressive addition lenses are widely applied to correct people's vision disorders, but the design and machining of progressive addition lenses are still difficult. Generally, a progressive addition lens has a freeform front surface and a spherical back surface. In this article, the design of the front surface was simplified as a minimization problem of a functional, and the solution was obtained directly using a variational-difference method. After solving this problem, the description of the surface was discussed, and an evaluation method was proposed to analyze the fitting accuracy of Zernike polynomial method and B-spline interpolation method with different degrees. As a result, the progressive addition lens surface was constructed by the method with smaller fitting error. Moreover, a new generation algorithm of entrance parameters for tool path generation was put forward, which can reduce the interpolation error. The experimental results indicate that the design method was feasible and the machined surface quality was satisfactory using the proposed algorithm.

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“…There are many factors that affect the machining efficiency and quality of sculptured surface parts. These factors exist in all aspects of the data flow of the machining process, 1 including the tool paths and the CL points generated by CAM, 2 the setpoints interpolated by the CNC system, the dynamic errors caused by servo control, the static/quasi-static errors of mechanical structures, the deformation and chatter during cutting, etc. Among all these factors, the CL points generated by CAM are located upstream of the data flow.…”

Section: Introductionmentioning

confidence: 99%

Calculation method of cutter location points considering corner transition speed in CNC

Lyu

Song

Han

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part B:

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The calculation method of cutter location (CL) points only considers the geometric errors, but cannot consider the requirements of the corner transition algorithm in CNC, which results in the smoothing algorithm in the CNC not playing a maximum role or even failing. To solve this problem, a calculation method of the CL points considering corner transition speed in CNC is proposed. Firstly, the key geometric parameters of the CL points that affect the corner speed are analyzed. Secondly, according to the analysis results, the objective function is established to connect the CL points calculation in CAM and the corner transition speed in CNC. By solving the objective function, the calculation method of the CL points is developed. Finally, the effectiveness of this method is verified by experiment. Comparing with the commonly used iso-chord height method, the proposed method can increase the speed at the corner of the CL points and reduce the acceleration and jerk at the same time. By the proposed method, the tracking accuracy, trajectory accuracy, and machining efficiency can be significantly improved. The proposed method can be integrated into CAM software to generate high quality CL points.

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Tool path optimal design for slow tool servo turning of complex optical surface

Cited by 12 publications

References 16 publications

Investigation on multi-body dynamics based approach to the toolpath generation for ultraprecision machining of freeform surfaces

Investigation on multi-body dynamics based approach to the toolpath generation for ultraprecision machining of freeform surfaces

Study on the variational-difference-based design and slow tool servo turning of progressive addition lenses

Calculation method of cutter location points considering corner transition speed in CNC

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