Slow tool servo diamond turning of optical freeform surface for astigmatic contact lens

2011 ◽  
Author(s):  
Chun-Chieh Chen ◽  
Yuan-Chieh Cheng ◽  
Wei-Yao Hsu ◽  
Hsiao-Yu Chou ◽  
Pei-Jen Wang ◽  
...  
Keyword(s):  
Contact Lens ◽  
Diamond Turning ◽  
Freeform Surface ◽  
Slow Tool Servo

Diamond Turning Freeform Optics

2007 ◽  
Vol 364-366 ◽  
pp. 1-6
Author(s):  
W. Jiang ◽  
Bill Tse ◽  
Roy Louie ◽  
Frankie Chan
Keyword(s):  
Diamond Turning ◽  
Freeform Surface ◽  
Work Piece ◽  
Freeform Optics ◽  
Milling Method ◽  
Slow Tool Servo ◽  
Optics Industry ◽  
Optics Fabrication ◽  
Five Axis ◽  
Machining Parameter

Freeform optics fabrication has become one of the hottest topics in optics industry in recent years. Although it still remains a challenge, many have tried different ways of manufacturing it. Some have achieved degrees of success. By means of a Nanotech 350-FG five axis diamond turning machine, we too have successfully produced some prototype freeform optics and lens arrays with Slow Tool Servo and Milling method. The produced freeform optics are mainly for automobile LED headlamps and the lens arrays are for LED illumination. In order to produce the freeform optics, we developed our own DT Slow Tool Servo program which is capable of generating a DT program for diamond turning a universal/general 3D freeform surface. Slow Tool Servo technique and Diamond Milling technique were mainly employed to produce these freeform surfaces. The manufacturing process and machining parameter details will be given in the paper. The two main methods we used will be compared and discussed as well. In measuring the freeform surface, a 3D white light interferometer was used to scan and obtain the surface coordinates. The software made by ourselves enabled us to compare the measure results of the work piece with that of the design drawings. The deviation of our finished forms is within 5 um from that of the nominal. The surface quality Rq is about 10 nm. Measuring equipment and methodology will also be discussed in the paper.

Freeform Surface Optical Components Machining by Slow Tool Servo Diamond Turning

2010 ◽  
Vol 47 (2) ◽  
pp. 022202
Author(s):  
关朝亮 Guan Chaoliang ◽  
戴一帆 Dai Yifan ◽  
尹自强 Yin Ziqiang
Keyword(s):  
Diamond Turning ◽  
Freeform Surface ◽  
Optical Components ◽  
Surface Optical ◽  
Slow Tool Servo

Modelling of Electrostatic Charge in Ultra-High Precision Diamond Turning of Contact Lens Polymer

2019 ◽  
Vol 298 ◽  
pp. 135-140
Author(s):  
Muhammad Mukhtar Liman ◽  
Khaled Abou El Hossein
Keyword(s):  
High Precision ◽  
Contact Lens ◽  
Feed Rate ◽  
Contact Lenses ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Electrostatic Charge ◽  
Diamond Turning ◽  
Depth Of Cut ◽  
Electrostatic Charges

The electrostatic charges encountered by a cutting tool when turning advanced contact lenses are important as they reflect the quality and condition of the tool, machine, fixture, and sometimes even the surface finished which is responsible for tool wear and poor surface quality. This study investigates the influence of cutting parameters namely cutting speed, feed rate and depth of cut on electrostatic charge (ESC) which play the leading role in determining the machine economics and quality of machining contact lens polymers. An electrostatic charge model based on response surface statistical method is developed for reliably predicting the values of static charging based on its relationship to cutting parameters in ultra-high precision diamond turning of contact lenses. It is clearly seen that all the model terms are significant with cutting speed having the highest degree of significance followed by feed rate and the interaction of speed and feed. However, depth of cut has the lowest degree of significance on the electrostatics charge.

Fabrication and correction of freeform surface based on Zernike polynomials by slow tool servo

Optifab 2017 ◽  
2017 ◽  
Author(s):  
Yuan-Chieh Cheng ◽  
Ming-Ying Hsu ◽  
Wei-Jei Peng ◽  
Wei-Yao Hsu
Keyword(s):  
Freeform Surface ◽  
Zernike Polynomials ◽  
Slow Tool Servo

Fuzzy logic-based modeling and analysis of surface roughness, electrostatic charge, and material removal rate in ultrahigh precision diamond turning of rigid contact lens polymer

2019 ◽  
pp. 089270571985060
Author(s):  
Muhammad Mukhtar Liman ◽  
Khaled Abou-El-Hossein ◽  
Lukman Niyi Abdulkadir
Keyword(s):  
Surface Roughness ◽  
Fuzzy Logic ◽  
Material Removal Rate ◽  
Contact Lens ◽  
Material Removal ◽  
Removal Rate ◽  
Electrostatic Charge ◽  
High Accuracy ◽  
Diamond Turning ◽  
Optical Manufacturing

Due to increasing demand for high accuracy and high-quality surface finish in optical industry, contact lens manufacturing requires reliable models for predicting surface roughness (Ra) which plays a very important role in the optical manufacturing industry. In this study, a Nanoform 250 ultra-grind turning machine was used for machining, while cutting speed, feed rate, and the depth of cut (with values selected to cover a wide range based on the literature) were considered as the machining parameters for a diamond turned rigid polymethylmethacrylate (PMMA) contact lens polymer. Turning experiments were designed and conducted according to Box–Behnken design which is a response surface methodology technique. Fuzzy logic-based artificial intelligence method was employed to develop an electrostatic charge (ESC), Ra, and material removal rate (MRR) prediction models. The accuracy and predictive ability of the fuzzy logic model was then judged by considering an average percentage error between experimental values and fuzzy logic predictions. Further, a comparative evaluation of experiments and fuzzy logic approach showed that the average errors of ESC, Ra, and MRR using fuzzy logic system were in tandem with experimental results. Hence, the developed fuzzy logic rules can be effectively utilized to predict the ESC, Ra, and MRR of a rigid PMMA contact lens polymers in automated optical manufacturing environments for high accuracy and computational cost.

scholarly journals Ultra-Precision Single-Point Diamond Turning of a Complex Sinusoidal Mesh Surface Using Machining Accuracy Active Control

2021 ◽  
Vol 67 (7-8) ◽  
pp. 343-351
Author(s):  
Peixing Ning ◽  
Ji Zhao ◽  
Shijun Ji ◽  
Jingjin Li ◽  
Handa Dai
Keyword(s):  
Active Control ◽  
Tool Path ◽  
Single Point ◽  
Diamond Turning ◽  
Machining Accuracy ◽  
Machining Error ◽  
Machined Surface ◽  
Mesh Surface ◽  
Slow Tool Servo ◽  
Radius Compensation

Single-point diamond turning (SPDT) assisted with slow tool servo (STS) is the most commonly utilized technique in the fabrication of optical modules. However, the tool path significantly affects the quality of the machined surface. In order to realize the determined machining accuracy effectively, a tool path generation (TPG) method based on machining accuracy active control (MAAC) is presented. The relationship between tool path and machining error is studied. Corner radius compensation (CRC) and the calculation of chord error and residual error are detailed. Finally, the effectiveness of the proposed approach is verified through a machining error simulation and a cutting experiment of a complex sinusoidal mesh surface fabrication.

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