scholarly journals Development of a Cost-Efficient Computer Controlled Optical Surfacing Process for Correcting Aspheric Lenses using Tool Influence Function based Dwelltime Optimization

2019 ◽  
Vol 215 ◽  
pp. 01002
Author(s):  
Pei Liang Low ◽  
Wilhelmus A. C. M. Messelink ◽  
Rene Weber
Keyword(s):  
Removal Rate ◽  
Surface Current ◽  
Aspheric Surfaces ◽  
Form Errors ◽  
Tool Influence Function ◽  
Convolution Model ◽  
Computer Controlled Optical Surfacing ◽  
Computer Controlled ◽  
Cost Efficient ◽  
Aspheric Lenses

A Computer Controlled Optical Surfacing (CCOS) system has been developed for correcting form errors on aspheric surfaces. Experiments were carried out to find the correlation between different polishing parameters and polishing metrics such as removal rate, uniformity etc. Based on established polishing parameters, polishing process is developed to correct surface errors on planar, spherical and aspheric surfaces. A convolution model between TIF and dwell times was developed to simulate and solve for correction polishing. Surface accuracies of peak-to-valley (PV) 141 nm and root-mean-squared (RMS) 22 nm has been achieved for planar surface. For aspheric surface, current accuracy of 662 nm PV and of 115 nm RMS is achieved with further development ongoing.

Study on Anastomosis Feature in Polishing Zone in Aspheric Optics Machining

2007 ◽  
Vol 364-366 ◽  
pp. 584-589
Author(s):  
Gui Lin Wang ◽  
Yi Fan Dai ◽  
Sheng Yi Li
Keyword(s):  
Removal Rate ◽  
Workpiece Material ◽  
Workpiece Surface ◽  
Mathematical Relation ◽  
Aspheric Optics ◽  
Relation Model ◽  
Computer Controlled Optical Surfacing ◽  
Computer Controlled ◽  
The Stability ◽  
Peak Value

In order to keep the stability of tool’s removal function, it is required that the anastomosis be tight between the tool and workpiece surface in Computer-controlled Optical Surfacing (CCOS). In this paper, the influence of tool’s character on anastomosis status is firstly studied. The relation model on the ratio of radius to thickness, Young's modulus of the tool, normal asphericity and normal arc height of workpiece surface is established, and the macroscopical condition of tight anastomosis is derived in aspheric optics machining. According to the microcosmic distribution of surface error, the mathematical relation between anastomosis error and removal rate is researched. In the end, the influence rule of anastomosis status on the convergence ratio of residual error is analyzed in machining zone. Based on the conclusion of machining instance, it is found that workpiece material would be fast removed in middle contact zone when the peak value of tool’s removal function locates in its center position.

scholarly journals Edge control in a computer controlled optical surfacing process using a heterocercal tool influence function

2016 ◽  
Vol 24 (23) ◽  
pp. 26809 ◽  
Author(s):  
Haixiang Hu ◽  
Xin Zhang ◽  
Virginia Ford ◽  
Xiao Luo ◽  
Erhui Qi ◽  
...  
Keyword(s):  
Influence Function ◽  
Tool Influence Function ◽  
Computer Controlled Optical Surfacing ◽  
Computer Controlled

scholarly journals A predictable smoothing evolution model for computer-controlled polishing

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Jing Hou ◽  
Pengli Lei ◽  
Shiwei Liu ◽  
Xianhua Chen ◽  
Jian Wang ◽  
...  
Keyword(s):  
Evolution Model ◽  
Quantitative Prediction ◽  
Theoretical Support ◽  
Model Combining ◽  
Process Guidance ◽  
Dependent Model ◽  
Computer Controlled Optical Surfacing ◽  
Computer Controlled ◽  
Time Dependent Model ◽  
Selection Of

AbstractQuantitative prediction of the smoothing of mid-spatial frequency errors (MSFE) is urgently needed to realize process guidance for computer controlled optical surfacing (CCOS) rather than a qualitative analysis of the processing results. Consequently, a predictable time-dependent model combining process parameters and an error decreasing factor (EDF) were presented in this paper. The basic smoothing theory, solution method and modification of this model were expounded separately and verified by experiments. The experimental results show that the theoretical predicted curve agrees well with the actual smoothing effect. The smoothing evolution model provides certain theoretical support and guidance for the quantitative prediction and parameter selection of the smoothing of MSFE.

Determination of cost-efficient cooling power range for improving the performance of internally cooled ultrasonic atomization liquid desiccant dehumidifiers

2020 ◽  
Vol 29 (9) ◽  
pp. 1260-1276
Author(s):  
Zili Yang ◽  
Lu-An Chen ◽  
Ruiyang Tao ◽  
Ke Zhong
Keyword(s):  
Power Efficiency ◽  
Removal Rate ◽  
Operating Conditions ◽  
Cooling Power ◽  
Internal Cooling ◽  
Liquid Desiccant ◽  
Improvement Rate ◽  
Ultrasonic Atomization ◽  
Internally Cooled ◽  
Cost Efficient

Liquid desiccant dehumidifiers (LDDs) can be improved by adding internal cooling. However, the addition of excessive cooling power may deteriorate the system‘s cost-efficiency, whereas the addition of insufficient cooling power leads to negligible performance improvements. The objective of this study is to determine the suitable cost-efficient cooling power range for improving the performance of internally cooled LDDs (IC-LDDs). A novel method and a set of criteria related to the moisture removal rate, cooling-power efficiency ( ηc) and coefficient of dehumidification performance from cooling power ( DCOPcooling) were proposed to determine cost-efficient cooling power. The internally cooled ultrasonic atomization liquid desiccant system (IC-UADS), together with a well-validated model based on the conservation laws of mass and energy and the sensible heat balance, was adopted to demonstrate the analysis. The results showed that, although the dehumidification performance improves with increasing cooling power, the improvement rate decreases, while ηcand DCOPcoolingdecline quickly (by 87.9%). For cost-efficient improvement, the necessary power proportion of internal cooling to the system‘s target dehumidification capacity tends to be stable, which was about 29% for the IC-UADS, and independent of the operating conditions. The results may help to determine the reasonable cooling power range for cost-efficient improvement of IC-LDDs.

scholarly journals An Elementary Approximation of Dwell Time Algorithm for Ultra-Precision Computer-Controlled Optical Surfacing

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 471
Author(s):  
Yajun Wang ◽  
Yunfei Zhang ◽  
Renke Kang ◽  
Fang Ji
Keyword(s):  
Dwell Time ◽  
Convergence Rates ◽  
Rotational Symmetry ◽  
Time Algorithm ◽  
Two Dimensions ◽  
Efficient Computation ◽  
Deconvolution Problem ◽  
Ultra Precision ◽  
Computer Controlled Optical Surfacing ◽  
Computer Controlled

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.

Research on the Optimized Tool-Path Planning of Computer Controlled Optical Surfacing

2011 ◽  
Vol 399-401 ◽  
pp. 1763-1767
Author(s):  
Ri Pan ◽  
Wei Yang ◽  
Yin Biao Guo ◽  
Feng Yang ◽  
Dong Xu Zhang
Keyword(s):  
Convergence Rate ◽  
Processing Time ◽  
Tool Path ◽  
Tool Path Planning ◽  
Tool Paths ◽  
High Convergence Rate ◽  
Computer Controlled Optical Surfacing ◽  
Computer Controlled ◽  
Removal Processes ◽  
Working Efficiency

Computer controlled optical surfacing (CCOS) is widely used in aspheric optical lenses fabrication because of their high convergence rate on surface based on deterministic removal processes since 1963. As an important part of CCOS techniques, reasonable tool-path would increase the polishing speed, decrease the processing time and then improve the efficiency of polishing. Optimized policy combined with improved Prim algorithm is presented in this paper based on the study of the characteristic of aspheric polishing and the tool-paths in common use. The simulated results show that the length of tool-path is reduced so as to decrease the processing time and increase the working efficiency.

scholarly journals New methods in provenance studies based on heavy minerals: an example from Miocene sands in Jylland, Denmark

2005 ◽  
Vol 7 ◽  
pp. 29-32 ◽  
Author(s):  
Christian Knudsen ◽  
Dirk Frei ◽  
Thomas Rasmussen ◽  
Erik S. Rasmussen ◽  
Roger McLimans
Keyword(s):  
Inductively Coupled Plasma ◽  
Mineral Exploration ◽  
Heavy Minerals ◽  
Compositional Variation ◽  
New Techniques ◽  
Preparation Methods ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Computer Controlled ◽  
Cost Efficient

New techniques using Computer Controlled Scanning Electron Microscopy (CCSEM) and Laser Ablation – Inductively Coupled Plasma – Mass Spectroscopy (LA-ICP-MS) have recently been developed at the Geological Survey of Denmark and Greenland (GEUS) to determine source, compositional variation and sedimentary pathways of sandstones. These new time- and cost-efficient methods are highly applicable in petroleum and mineral exploration. This paper illustrates how the provenance and variability of Miocene titanium-rich sands in western and central Jylland have been investigated, but the methods are presently also used offshore the Faroe Islands and in East and West Greenland. CCSEM and LA-ICP-MS utilise simple sample preparation methods, are relatively rapid and less expensive than conventional methods and yield more information.

on Large-scale dwell time algorithm for computer controlled optical surfacing

2011 ◽  
Vol 23 (12) ◽  
pp. 3207-3212
Author(s):  
罗丽丽 Luo Lili ◽  
何建国 He Jianguo ◽  
王亚军 Wang Yajun ◽  
张云飞 Zhang Yunfei ◽  
黄文 Huang Wen ◽  
...  
Keyword(s):  
Dwell Time ◽  
Large Scale ◽  
Time Algorithm ◽  
Computer Controlled Optical Surfacing ◽  
Computer Controlled
Sign in / Sign up

Export Citation Format

Share Document