Modelling and simulation of structure surface generation using computer controlled ultra-precision polishing

2011 ◽  
Vol 35 (4) ◽  
pp. 574-590 ◽  
Author(s):  
C.F. Cheung ◽  
L.B. Kong ◽  
L.T. Ho ◽  
S. To
Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 755
Author(s):  
Chen-Yang Zhao ◽  
Chi-Fai Cheung ◽  
Wen-Peng Fu

In this paper, an investigation of cutting strategy is presented for the optimization of machining parameters in the ultra-precision machining of polar microstructures, which are used for optical precision measurement. The critical machining parameters affecting the surface generation and surface quality in the machining of polar microstructures are studied. Hence, the critical ranges of machining parameters have been determined through a series of cutting simulations, as well as cutting experiments. First of all, the influence of field of view (FOV) is investigated. After that, theoretical modeling of polar microstructures is built to generate the simulated surface topography of polar microstructures. A feature point detection algorithm is built for image processing of polar microstructures. Hence, an experimental investigation of the influence of cutting tool geometry, depth of cut, and groove spacing of polar microstructures was conducted. There are transition points from which the patterns of surface generation of polar microstructures vary with the machining parameters. The optimization of machining parameters and determination of the optimized cutting strategy are undertaken in the ultra-precision machining of polar microstructures.


Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 471
Author(s):  
Yajun Wang ◽  
Yunfei Zhang ◽  
Renke Kang ◽  
Fang Ji

The dwell time algorithm is one of the key technologies that determines the accuracy of a workpiece in the field of ultra-precision computer-controlled optical surfacing. Existing algorithms mainly consider meticulous mathematics theory and high convergence rates, making the computation process more uneven, and the flatness cannot be further improved. In this paper, a reasonable elementary approximation algorithm of dwell time is proposed on the basis of the theoretical requirement of a removal function in the subaperture polishing and single-peak rotational symmetry character of its practical distribution. Then, the algorithm is well discussed with theoretical analysis and numerical simulation in cases of one-dimension and two-dimensions. In contrast to conventional dwell time algorithms, this proposed algorithm transforms superposition and coupling features of the deconvolution problem into an elementary approximation issue of function value. Compared with the conventional methods, it has obvious advantages for improving calculation efficiency and flatness, and is of great significance for the efficient computation of large-aperture optical polishing. The flatness of φ150 mm and φ100 mm workpieces have achieved PVr150 = 0.028 λ and PVcr100 = 0.014 λ respectively.


2015 ◽  
Vol 105 (06) ◽  
pp. 366-370
Author(s):  
L. Schönemann ◽  
W. Preuß ◽  
O. Riemer ◽  
E. Foremny ◽  
E. Brinksmeier ◽  
...  

Die ultrapräzise Fräsbearbeitung ist eine flexible Möglichkeit zur Herstellung optischer Freiformflächen. Aufgrund der hohen Genauigkeitsanforderungen kommen hierbei jedoch zumeist einschneidige Werkzeuge und niedrige Spindeldrehzahlen zum Einsatz. Diese Arbeit zeigt zwei neue Ansätze zur Steigerung der Flächenleistung in der Ultrapräzisionsbearbeitung: den Einsatz thermisch verstellbarer Mehrfachwerkzeuge sowie die Verwendung ultrapräziser Hochgeschwindigkeitsspindeln in Verbindung mit neuen Methoden zur Auswuchtung.   Ultraprecision milling is a flexible process for generating optical freeform surfaces. Due to the tight tolerances of such parts, only single-edge tools and low spindle frequencies are applied. This publication presents two novel approaches to increase the surface generation rate in ultraprecision machining: the use of milling tools with multiple cutting edges that are aligned via a thermomechanical actuator and the application of high speed spindels that require novel approaches for balancing.


Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 573
Author(s):  
Zhang ◽  
Guo ◽  
Chen ◽  
Fu ◽  
Zhao

The surface generation mechanism of the Cu alloys in ultra-precision diamond turning is investigated by both simulation and experimental methods, where the effects of the cutting parameters on the surface characteristics are explored, including the workpiece spindle speed, the cutting depth, the feed rate and the nose radius of the diamond tool. To verify the built model, the cutting experiments are conducted at selected parameters, where the causes of the error between the simulation and the machining results are analyzed, including the effects of the materials microstructure and the diamond tool wear. In addition, the nanometric surface characteristics of the Cu alloys after the diamond turning are identified, including the finer scratching grooves caused by the tool wear, the formation of the surface burs and the adhesion of graphite. The results show that the built model can be basically used to predict the surface topography for the selection of the appropriate machining parameters in the ultra-precision diamond turning process.


2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774714
Author(s):  
Dongju Chen ◽  
Xianxian Cui ◽  
Ri Pan ◽  
Jinwei Fan ◽  
Chenhui An

In ultra-precision fly-cutting machining, the aerostatic spindle is the key component, which has significant influence on the machined surface quality. The unbalanced spindle directly affects the machining accuracy. In this article, a prediction model of machining surface topography is proposed which involves the effect of the gas film performance of spindle in microscale. With the Weierstrass function, unstable transient response of the aerostatic spindle system is derived by the motion model of the spindle, which response signal represents the surface profile in the ultra-precision machining. Meanwhile, the experiment is performed with different rotation speed of the spindle. And the effect of the unbalanced aerostatic spindle on the surface generation is discussed in time and frequency domain. The conclusion shows that the similar cyclical surface ripple of the workpiece is independent of the spindle speed, and the rotation speed of the spindle and unbalanced spindle directly affects the machining surface topography. This study is quite meaningful for deeply understanding the influence rule of spindle unbalanced error from the viewpoint of machined surface and vibration frequency.


2016 ◽  
Vol 1136 ◽  
pp. 221-226
Author(s):  
Lan Zhan ◽  
Fei Hu Zhang ◽  
Chen Hui An ◽  
Zhi Peng Li

Ultra-precision fly cutting machines have long been the hardest one to compliant and induce great focus of researchers. In this paper, a surface topography model is proposed to predict the surface generation in an ultra-precision fly cutting machine. The building of surface topography model is based on the trace of the tool tip. With the 3D surface profile simulations of workpieces, several influencing factors of surface topography, especially the factors related to micro waviness error, are studied.


2009 ◽  
Vol 209 (8) ◽  
pp. 4178-4185 ◽  
Author(s):  
L.B. Kong ◽  
C.F. Cheung ◽  
S. To ◽  
W.B. Lee

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