A Study on the Grinding to Improve Profile Accuracy of Aspheric Lens

2007 ◽  
Vol 364-366 ◽  
pp. 1168-1173
Author(s):  
Seung Yub Baek ◽  
Eun Sang Lee ◽  
Jong Koo Won
Keyword(s):  
Surface Roughness ◽  
Tool Path ◽  
Production Costs ◽  
Total Production ◽  
Precision Grinding ◽  
Aspheric Lens ◽  
Ultra Precision ◽  
Grinding Technique ◽  
Profile Accuracy ◽  
Grinding System

This study presents the development of an ultra-precision grinding system based on a new grinding technique called the “In-Process Grinding Method (IPGM)”. IPGM which is used for grinding aspheric lens increases both the production and grinding performance, and significantly decreases total production costs. To enhance the precision grinding productivity of ultra-precision aspheric lens, we present here an ultra-precision grinding system and process for the aspheric micro-lens. The tool path was calculated and CNC program generation and tool path compensation were performed for aspheric lens. Using this ultra-precision grinding system, aspheric lens, 4mm in diameter, were successfully performed. The profile error after the first grinding without any compensation was less than 0.6μm, and surface roughness Ra was 0.01μm. In-process grinding was performed with compensation. Results of the profile accuracy P-V 0.3μm and surface roughness Ra 0.006 μm were obtained.

An Experimental Investigation of Optimal Grinding Condition for Aspheric Surface Lens Using Full Factorial Design

2007 ◽  
Vol 329 ◽  
pp. 27-32 ◽  
Author(s):  
Seung Yub Baek ◽  
Jung Hyung Lee ◽  
Eun Sang Lee ◽  
H.D. Lee
Keyword(s):  
Surface Roughness ◽  
Ground Surface ◽  
Diamond Wheel ◽  
Aspheric Surface ◽  
Precision Grinding ◽  
Spherical Lens ◽  
Ultra Precision ◽  
Ground Surface Roughness ◽  
Grinding System ◽  
Micro Lens

To enhance the precision and productivity of ultra precision aspheric surface micro lens, the development of ultra-precision grinding system and process for the aspheric surface micro lens are described. In this paper, an ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the grinding surface roughness and profile accuracy. This paper deals with the mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and with the spherical lens of BK7. The optimization of grinding conditions with respect to ground surface roughness and profiles accuracy is investigated by design of experiments.

Development of an ultra-precision grinding system for machining optical aspheric components with a large depth—diameter ratio

2002 ◽  
Vol 216 (11) ◽  
pp. 1471-1479 ◽  
Author(s):  
M Chen ◽  
Q Zhao ◽  
S Dong ◽  
D Li
Keyword(s):  
Surface Roughness ◽  
Diamond Wheel ◽  
Linear Displacement ◽  
Diameter Ratio ◽  
Large Depth ◽  
High Profile ◽  
Machining Errors ◽  
Ultra Precision ◽  
Profile Accuracy ◽  
Grinding System

When grinding a large depth—diameter ratio aspheric part of high precision and high quality, the factors influencing surface roughness and profile accuracy of machined surfaces were theoretically analysed first. Afterwards the authors designed and manufactured the ultra-precision aspheric grinding system. The workpiece spindle, transverse guideway, longitudinal guideway and the grinder spindle are in aerostatic form. Turning accuracy of the workpiece spindle is 0.05 μm, the maximum rotational speed of the grinder is 80 000 r/min and the turning accuracy is 0.1 μm, and the resolution of linear displacement of the transverse and longitudinal guideway is 4.9 nm. The accuracy of the precise adjusting mechanism is 0.1 μm. The discharge principle of the dressing mechanism was developed in order to dress the diamond wheel. The ball-headed wheel has high profile accuracy after dressing. This mechanism solved the problem of on-position dressing of the case iron bonded diamond wheels and reduced the machining errors for aspheric surface components. Finally, grinding experiments for machining aspheric components were carried out. The grinding results indicated that the achieved profile accuracy is 0.3 μm and the surface roughness is less than 0.01 μm.

Research on the 3-Axis CNC Ultra-Precision Grinding of Aspheric Mould

2009 ◽  
Vol 69-70 ◽  
pp. 39-43 ◽  
Author(s):  
Li Jun Li ◽  
Fei Hu Zhang ◽  
Shen Dong
Keyword(s):  
Influence Factors ◽  
Grinding Wheel ◽  
Aspheric Surface ◽  
Precision Grinding ◽  
Form Accuracy ◽  
Form Errors ◽  
Machining Test ◽  
Ultra Precision ◽  
Grinding System ◽  
Parallel Grinding

Parallel grinding is an effective method of aspheric moulds machining which is usually made of industrial ceramic such as silicon carbide (SiC) or tungsten carbide (WC), but if the spherical grinding wheel is not being with precision truing and dressing, the roughness and form accuracy of the ground aspheric surface should get worse, for this reason, in this paper, the influence factors of thoroughness and form accuracy induced by the wheel truing and dressing are studied firstly, and a new 3-axis CNC Ultra-precision grinding system which is based on the PMAC (Programmable Multi-axes Controller) is developed, through simultaneous motion of the controlled X, Z and B axis, the form errors which is induced by the grinding wheel can be improved theoretically, and the aspheric mould machining test shown that the surface roughness of Ra 0.025μm and the form accuracy of P-V 1.15μm are achieved.

Study of The Tool Path Generation Method of an Ultra-Precision Spherical Complex Surface Based on a Five-Axis Machine Tool

2021 ◽  
Author(s):  
Tianji Xing ◽  
Xuesen Zhao ◽  
Zhipeng Cui ◽  
Rongkai Tan ◽  
Tao Sun
Keyword(s):  
Surface Roughness ◽  
Tool Path ◽  
Spherical Surface ◽  
Tool Path Generation ◽  
Path Generation ◽  
Tool Paths ◽  
Spherical Surfaces ◽  
Spherical Complex ◽  
Ultra Precision ◽  
Five Axis

Abstract The improvement of ultra-precision machining technology has significantly boosted the demand for the surface quality and surface accuracy of the workpieces to be machined. However, the geometric shapes of workpiece surfaces cannot be adequately manufactured with simple plane, cylindrical, or spherical surfaces because of their different applications in various fields. In this research, a method was proposed to generate tool paths for the machining of complex spherical surfaces based on an ultra-precise five-axis turning and milling machine with a C-Y-Z-X-B structure. Through the proposed tool path generation method, ultra-precise complex spherical surface machining was achieved. First, the complex spherical surface model was modeled and calculated, and then it was combined with the designed model to generate the tool path. Then the tool paths were generated with a numerically controlled (NC) program. Based on an ultra-precision three-coordinate measuring instrument and a white light interferometer, the machining accuracy of a workpiece surface was characterized, and t[1]he effectiveness of the provided tool path generation method was verified. The surface roughness of the machined workpiece was less than 90 nm. Furthermore, the surface roughness within the spherical region appeared to be less than 30 nm. The presented tool path generation method in this research produced ultra-precision spherical complex surfaces. The method could be applied to complex spherical surfaces with other characteristics.

Thermal Analysis of Laser Irradiation of Fused Silica

2011 ◽  
Vol 314-316 ◽  
pp. 1960-1964 ◽  
Author(s):  
Peng Yao ◽  
Ya Dong Gong ◽  
Suo Xian Yuan ◽  
Tian Feng Zhou ◽  
Ji Wang Yan ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Surface Roughness ◽  
Laser Irradiation ◽  
Fused Silica ◽  
Maximum Temperature ◽  
Precision Grinding ◽  
Micro Cracks ◽  
Ductile Mode ◽  
Ultra Precision ◽  
Simulation Results

To grind fused silica in ductile mode, surface and subsurface micro cracks (SSMC) on ground fused silica should be repaired by CO2 laser irradiation before ultra-precision grinding. In this paper, 2D thermal analysis of single pass laser irradiation of fused silica was conducted, and the simulation results were discussed by comparing with the experiment results. To repair SSMC and decrease the surface roughness of ground fused silica simultaneously, the maximum temperature on the surface during laser irradiation should be controlled higher than 3280 K and lower than 3550 K.

Optimising the Process Conditions in Ultra-Precision Grinding to Achieve Surface Finish of Optical Quality

2006 ◽  
Vol 304-305 ◽  
pp. 8-13 ◽  
Author(s):  
T. Jin ◽  
D.J. Stephenson
Keyword(s):  
Surface Roughness ◽  
Surface Finish ◽  
Material Removal ◽  
Removal Rate ◽  
Optical Quality ◽  
Process Conditions ◽  
Low Alloy Steel ◽  
Optical Surface ◽  
Precision Grinding ◽  
Ultra Precision

Optical surface finish below Ra 10nm can be achieved on a ‘Tetraform C’ grinder of ultra-high stiffness, when grinding a low alloy steel with or without the help of ELID (electrolytic in process dressing). Surface roughness generation modelling has been carried out to predict thepossible surface roughness values. Efforts have been made to transfer the process knowledge to different grinding mode using a rigid 5-axis Edgetek CNC grinder. The effects of material removal rate and grit size and also that of spark out passes on the surface roughness generated have been investigated.

Case study for sampling effect in nanometric surface roughness of ultra-precision grinding

2020 ◽  
pp. 095440892095259
Author(s):  
Shaojian Zhang ◽  
Wei Peng ◽  
Zhiwen Xiong ◽  
Suet To
Keyword(s):  
Surface Roughness ◽  
Spatial Frequency ◽  
High Spatial Frequency ◽  
Precision Grinding ◽  
Sampling Effect ◽  
Measurement Traceability ◽  
Ultra Precision ◽  
Frequency Features ◽  
Insight Into

Nanometric surface roughness (NSR) is commonly produced in ultra-precision grinding (UPG). However, the NSR would be significantly affected by the sampling frequency (SF), i.e. sampling effect, since it is governed by rich low, middle, and high spatial frequency features. Hereby, the case study focused on discussing sampling effect in the NSR of UPG. The theoretical and experimental results have been found that along with the SF increase the NSR rises and rapidly converges and the SF is over 10 times of the spatial frequency for the NSR within the 5% distortion. Moreover, the NSR is acceptable within its 5% variation ratio under two SFs. Further, the SFs should be provided as the measurement traceability, together. Significantly, the case study draws up a better insight into sampling effect in the NSR of UPG along with a feasible suggestion on its measurement.

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