scholarly journals Adaptive Spiral Tool Path Generation for Diamond Turning of Large Aperture Freeform Optics

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 810 ◽  
Author(s):  
Dongfang Wang ◽  
Yongxin Sui ◽  
Huaijiang Yang ◽  
Duo Li

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.

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yahui Nie ◽  
Yinfei Du ◽  
Zhuo Xu ◽  
Zimiao Zhang ◽  
Yang Qi

Freeform optics are defined as nonrotational symmetric optical surfaces in the manufacturing industry. Freeform optics are extensively applied to many areas in order to improve system performance. Fast tool servo (FTS) assisting single-point diamond turning technology has high application prospects in freeform optics machining. This paper discusses the interpolation algorithm for tool path generation of FTS through the application of a radial basis function (RBF) algorithm. For this purpose, a positive definite RBF with compact support was employed as the interpolant. The existence is mathematically proven. Numerical simulations were performed to compare the performances of the RBF algorithm and commonly used algorithms for satisfying the requirements of existence, smoothness, and accuracy. Machining experiments were also conducted to validate the applicability of the algorithm. The simulation results showed that the RBF interpolation algorithm outperformed other algorithms in terms of smoothness. The RBF algorithm also provided the highest interpolation accuracy. Furthermore, the RBF interpolation algorithm exhibited the highest accuracy for error distribution, with large errors distributed mainly in transition areas. The machining results were also in general agreement with the simulation results although obvious practical errors were observed. Overall, RBF interpolation can provide higher accuracy and better smoothness in the tool path generation of FTS.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2566 ◽  
Author(s):  
Duo Li ◽  
Zheng Qiao ◽  
Karl Walton ◽  
Yutao Liu ◽  
Jiadai Xue ◽  
...  

Freeform surfaces are featured with superior optical and physical properties and are widely adopted in advanced optical systems. Slow tool servo (STS) ultra-precision machining is an enabling manufacturing technology for fabrication of non-rotationally symmetric surfaces. This work presents a theoretical and experimental study of surface topography generation in STS machining of freeform surfaces. To achieve the nanometric surface topography, a systematic approach for tool path generation was investigated, including tool path planning, tool geometry selection, and tool radius compensation. The tool radius compensation is performed only in one direction to ensure no high frequency motion is imposed on the non-dynamic axis. The development of the surface generation simulation allows the prediction of the surface topography under various tool and machining variables. Furthermore, it provides an important means for better understanding the surface generation mechanism without the need for costly trial and error tests. Machining and measurement experiments of a sinusoidal grid and microlens array sample validated the proposed tool path generation and demonstrated the effectiveness of the STS machining process to fabricate freeform surfaces with nanometric topography. The measurement results also show a uniform topography distribution over the entire surface and agree well with the simulated results.


Author(s):  
Xu Chen ◽  
Min Kang ◽  
Xingsheng Wang ◽  
Muhammad Hassan ◽  
Jun Yang

In order to increase the machining accuracy of slow tool servo turning of complex optical surface, the optimal design for tool path was studied. A comprehensive tool path generation strategy was proposed to optimize the tool path for machining complex surfaces. A new algorithm was designed for tool nose radius compensation which had less calculation error. Hermite segment interpolation was analyzed based on integrated multi-axes controller, and a new interpolation method referred to as triangle rotary method was put forward and was compared with the area method and three-point method. The machining simulation indicated that the triangle rotary method was significant in error reduction. The interpolation error of toric surface was reduced to 0.0015 µm from 0.06 µm and sinusoidal array surface’s interpolation error decreases to 0.37 µm from 1.5 µm. Finally, a toric surface was machined using optimum tool path generation method to evaluate the proposed tool path generation method.


2019 ◽  
Vol 2 (3) ◽  
pp. 118-124 ◽  
Author(s):  
Hu Gong ◽  
Shengjun Ao ◽  
Kuntao Huang ◽  
Yi Wang ◽  
Changya Yan

2013 ◽  
Vol 774-776 ◽  
pp. 1438-1441
Author(s):  
Xiao Bing Chen ◽  
Kun Yu

The machining efficiency of conventional section plane method is low for complex mesh surface machining. An efficient method for tool path generation based on region intersection is proposed. The mesh surface is first divided into a series of intersection regions, then vertex curvatures in perpendicular directions of tool paths are estimated by local fitting method, and variable tool path intervals are computed according to the curvatures, scallop height and cutter radius, finally redundant cutter location points are removed according to machining precision. Experiment results indicate that tool paths generated by proposed method are avail to promote machining efficiency of complex mesh surface machining.


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