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

Author(s):  
Shaojian Zhang ◽  
Wei Peng ◽  
Zhiwen Xiong ◽  
Suet To

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.

2011 ◽  
Vol 314-316 ◽  
pp. 1960-1964 ◽  
Author(s):  
Peng Yao ◽  
Ya Dong Gong ◽  
Suo Xian Yuan ◽  
Tian Feng Zhou ◽  
Ji Wang Yan ◽  
...  

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.


2006 ◽  
Vol 304-305 ◽  
pp. 8-13 ◽  
Author(s):  
T. Jin ◽  
D.J. Stephenson

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.


2007 ◽  
Vol 329 ◽  
pp. 27-32 ◽  
Author(s):  
Seung Yub Baek ◽  
Jung Hyung Lee ◽  
Eun Sang Lee ◽  
H.D. Lee

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.


2007 ◽  
Vol 364-366 ◽  
pp. 1168-1173
Author(s):  
Seung Yub Baek ◽  
Eun Sang Lee ◽  
Jong Koo Won

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.


2012 ◽  
Vol 229-231 ◽  
pp. 542-546
Author(s):  
J.L. Guan ◽  
Li Li Zhu ◽  
H.W. Lu ◽  
Zhi Wei Wang

In this document, the electrolytic in-process dressing ( ELID ) grinding technique is used for ultra-precision processing experimental research on the carbonized cold-rolled steel (HRC60~80).A surface roughness of Ra6~8nm was obtained after ELID precision grinding. The results proved that adopting micro grain size (W1.5~W36) and high hardness cast iron based diamond grinding wheel, increasing the wheel peripheral velocity (18~20m/s) and reducing grinding depth can effectively improve surface quality and bring the surface roughness down. The wheel peripheral velocity, grinding depth as well as grinding fluid are the main factors during ultra-precision grinding.


2017 ◽  
Vol 872 ◽  
pp. 19-24
Author(s):  
Zong Chao Geng ◽  
Shang Gao ◽  
Ren Ke Kang ◽  
Zhi Gang Dong

Quartz glass is a typical hard and brittle material. During the manufacturing process of quartz glass components, ultra-precision grinding is widely used due to its high throughput and good dimensional accuracies. However, grinding will unavoidably induce large surface and subsurface damage. In this study, the surface and subsurface damage characteristics of quartz glass substrates ground by diamond wheels with different grit sizes were investigated in terms of surface roughness, surface topography, subsurface microcrack characteristic, and subsurface damage depth. Discussion was also provided to explore corresponding reasons of surface and subsurface damage induced by diamond grinding wheels with different grit sizes of #1500 and #2000. The experiment results showed that the surface roughness, surface damage, and subsurface damage depth induced by #2000 quartz glass was ground by #1500 diamond grinding wheel, and in ductile mode when ground by #2000 diamond grinding wheel.


Author(s):  
Đỗ Minh Cường ◽  
Zhu shi Hong ◽  
Nguyễn Thị Ngọc ◽  
Farman Ali Chandio

Determination of accurate paddy field surface profile has great importance to designing the paddy tractor suspension system. With this aim, a new test rig has been designed and developed to measure paddy field surface profiles using static level method (sampled interval of 200mm). The data were analyzed through Matlab/Simulink software to obtain power spectral densities (0.05-3.5c/m) of the measured profiles on a log-log scale and it was found that the amplitude variation of the power spectral density (PSD) at low spatial frequency was higher than at high spatial frequency whereas the undulation of the PSD curve was largely changed from low to high frequency with roughness coefficient of 645.06x10-6 m3/cycle and slope value of 1.2399  representing the paddy field surface roughness under class D of ISO 8608 standards. This classification has great significance in the field of tractor vibration simulation work. Keywords: Paddy field surface, Rod and Level, Static level method, ISO 8608.


2012 ◽  
Vol 516 ◽  
pp. 287-292 ◽  
Author(s):  
Ekkard Brinksmeier ◽  
Yildirim Mutlugünes ◽  
Grigory Antsupov ◽  
Kai Rickens

This paper presents advanced tools for ultra precision grinding which offer a high wear resistance and can be used to generate high-quality parts with an ultraprecise surface finish. The first approach features defined dressed, coarse-grained, single layered, metal bonded diamond grinding wheels. These grinding wheels are called Engineered Grinding Wheels and have been dressed by an adapted conditioning process which leads to uniform abrasive grain protrusion heights and flattened grains. This paper shows the results from grinding optical glasses with such Engineered Grinding Wheels regarding the specific forces and the surface roughness. The results show that the cutting mechanism turns into ductile removal and optical surfaces are achievable. On the other hand, the specific normal force F´n increases due to increased contact area of the flattened diamond grains. It is shown that the topography of the Engineered Grinding Wheels has a strong beneficial influence on surface roughness. The second new tool for ultra precision grinding is made of a CVD (Chemical Vapour Deposition) poly-crystalline diamond layer with sharp edges of micrometre-sized diamond crystallites as a special type of abrasive. The sharp edges of the crystallites act as cutting edges which can be used for grinding. It is shown that by using CVD-diamond-coated grinding wheels a high material removal rate and a high surface finish with surface roughness in the nanometre range can be achieved. The CVD-diamond layers exhibit higher wear resistance compared to conventional metal and resin bonded diamond wheels. In conclusion, this paper shows that not only conventional fine grained, multi-layered resinoid diamond grinding wheels but also coarse-grained and binderless CVD-coated diamond grinding wheels can be applied to machine brittle and hard materials by ultra precision grinding.


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