Nano-Topography Distribution on Non-Axisymmetric Aspherical Ground Surface

2011 ◽  
Vol 325 ◽  
pp. 66-71 ◽  
Author(s):  
Nobuhito Yoshihara ◽  
Shin Fujimura ◽  
Naohiro Nishikawa ◽  
Masahiro Mizuno ◽  
Toshirou Iyama

Both form accuracy and smooth surface is required in precision grinding. And the form accuracy and surface roughness are improved year by year. However, the more the surface roughness becomes smoother, the more the grinding marks become remarkable. The grinding mark deteriorates the accuracy of optical parts. It is found that the vibration of grinding wheel is transcribed to the ground surface and forms the waviness named nano-topography. And the nano-topography causes grinding marks. In this study, relationship between the nano-topography on non-axisymmetric aspherical ground surface and grinding condition is analyzed theoretically to control the distribution of nano-topography. As a result, simulation method of nano-topography distribution is developed.

2014 ◽  
Vol 1017 ◽  
pp. 109-113 ◽  
Author(s):  
Nobuhito Yoshihara ◽  
Tomoharu Nakagawa ◽  
Naohiro Nishikawa ◽  
Masahiro Mizuno

Form accuracy and smooth surface is required in precision grinding. And the form accuracy and surface roughness are improved year by year. However, the more the surface roughness becomes smooth, the more the grinding marks become remarkable. The grinding mark deteriorates the uniformity of ground surface. In this study, relationship between the uniformity of non-axisymmetric aspherical ground surface and grinding condition is analyzed theoretically. As a result, it is found that there are optimum grinding conditions.


2007 ◽  
Vol 329 ◽  
pp. 495-500
Author(s):  
Hang Gao ◽  
W.G. Liu ◽  
Y.G. Zheng

It is experimentally found that existing micro-holes or micro-concaves on the cemented carbide base surface of electroplated CBN wheel is one of important reasons to worsen the combining intensity of the electroplated abrasives layer with the grinding wheel base. It is well solved by sealing the holes or concaves with steam sealing method. Further more the electroplated CBN wheel with cemented carbide base for precision grinding of compressor cylinder vane slot is developed by optimizing the electroplating prescription and process. Productive grinding results show that the ground surface roughness, size precision and the wheel life have reached the advanced index of the same type of wheel imported.


2007 ◽  
Vol 24-25 ◽  
pp. 261-264 ◽  
Author(s):  
Y. Hasuda ◽  
Y. Suzuki ◽  
Y. Tadokoro ◽  
S. Kinebuchi ◽  
T. Ohashi ◽  
...  

The fundamental experiment of the grinding of the stainless steel using the metal bonded CBN wheel which was excellent in wear resistance was conducted. The most appropriate grinding conditions were obtained by clarifying wear process of grinding wheel and finished ground surface quality. When grinding was carried out up to stock removal 7000mm3/mm, radial wear of grinding wheel %R is 3μm and surface roughness Rz was 0.5μm or less. The grinding ratio Gr becomes about 3000, and long life grinding with little change of surface roughness was possible.


2014 ◽  
Vol 625 ◽  
pp. 475-479 ◽  
Author(s):  
Bing Guo ◽  
Qing Liang Zhao ◽  
Yan Hou ◽  
Cheng Ge ◽  
Xin Yu

Microstructured optical elements made of glass are generally replicated by hot pressing with super-hard materials, such as binderless tungsten carbide (WC) and precision ceramic. However, in grinding of microstructures, problems frequently occur in terms of rough ground surface, chipping and rounding of micro-structures edges when compared to conventional grinding. In order to overcome these technological constraints, a promising precision grinding method for microstructured surfaces that applies ultrasonic vibration to improve the surface quality, and protect the edges and tips of microstructured surfaces is presented. The experimental investigation of ultrasonic vibration assisted grinding of microstructures on binderless WC is researched. The effects of ultrasonic vibration on surface roughness, form accuracy and edge radius were analyzed. The morphology of surface and array edges was examined with a scanning electron microscope (SEM), while the surface roughness was measured by a laser interferometer. And a contact probe profilometer was used to assess the form of array and radius of microstructured edges. Experimental results showed that the application of ultrasonic vibration leads to significant improvements of the surface roughness and edges of microstructures compared with traditional precision grinding processes. A micro cylinder lens array of binderless WC with surface roughness of 78nm and edge radius of less than 1μm was obtained. The novel grinding method is feasible and applicable in machining higher form accuracy microstructures.


2013 ◽  
Vol 1 (4) ◽  
Author(s):  
Kazutoshi Katahira ◽  
Jun Komotori

In this study, efficient, high-precision grinding of cemented carbide alloys using a specific grinding wheel was performed, and the ground surface characteristics were investigated in detail. The results showed that final finishing using a chromium-bonded wheel produced an extremely smooth surface with an average roughness Ra of 4 nm. The grinding process produced a chromium- and copper-rich surface layer, as well as a large amount of diffusion of oxygen. Adhesive strength tests using a microscratching method were also carried out on ground substrates coated with diamond-like carbon (DLC) films. The surface ground by the chromium-bonded wheel exhibited superior adhesive strength due to its strong chemical affinity with the DLC film.


2016 ◽  
Vol 686 ◽  
pp. 125-130 ◽  
Author(s):  
Miroslav Neslušan ◽  
Jitka Baďurová ◽  
Anna Mičietová ◽  
Maria Čiliková

This paper deals with cutting ability of progressive Norton Quantum grinding wheel during grinding roll bearing steel 100Cr6 of hardness 61 HRC. Cutting ability of this wheel is compared with conventional grinding wheel and based on measurement of grinding forces as well as surface roughness. Results of experiments show that Norton Quantum grinding wheels are capable of long term grinding cycles at high removal rates without unacceptable occurrence of grinding chatter and surface burn whereas application of conventional wheel can produce excessive vibration and remarkable temper colouring of ground surface. Moreover, while Norton Quantum grinding wheel gives nearly constant grinding forces and surface roughness within ground length at higher removal rates, conventional grinding wheel (as that reported in this study) does not.


2009 ◽  
Vol 69-70 ◽  
pp. 39-43 ◽  
Author(s):  
Li Jun Li ◽  
Fei Hu Zhang ◽  
Shen Dong

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.


2007 ◽  
Vol 329 ◽  
pp. 465-470 ◽  
Author(s):  
Nobuhito Yoshihara ◽  
Ji Wang Yan ◽  
Tsunemoto Kuriyagawa

Aspherical surfaces are an important technology in optical instruments. Until now, only improvements in form accuracy and surface roughness of aspherical surfaces have been investigated. However, when the surface roughness becomes low, the small waviness of the surface becomes marked. This small waviness is termed “Nano-topography.” Nano-topography causes grinding marks and reduces the accuracy of an optical instrument. Nano-topography is caused by the vibration of a grinding wheel during the manufacture of the surface. This paper will reveal how a rubber-bonded grinding wheel has been developed to absorb that vibration. The dressing of the grinding wheel was also investigated. As a result, it is possible to eliminate the generation of nano-topography.


2010 ◽  
Vol 97-101 ◽  
pp. 4206-4212 ◽  
Author(s):  
Shao Hui Yin ◽  
Feng Jun Chen ◽  
Yu Wang ◽  
Yu Feng Fan ◽  
Yong Jian Zhu ◽  
...  

A compensation method was proposed for correcting wheel setting error and residual form error in nanogrinding of axisymmetric surfaces. In this method, profile data from on-machine measurement were used to obtain the setting error of grinding wheel, as well as the normal residual form error. Compensation model of single-point inclined-axis grinding was built up for generating new compensation path. Grinding test of aspheric tungsten carbide mould was conducted to evaluate performances of the compensation method. A profile error of 182 nm (peak to valley) and average surface roughness of 1.71 nm were achieved. These results indicated that the form error compensation method may significantly improve form accuracy of ground surface.


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.


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