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

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.

2011 ◽  
Vol 487 ◽  
pp. 500-504
Author(s):  
Li Jun Li ◽  
Y. Jiang ◽  
Fei Hu Zhang

The manufacturing system developed in this paper is mainly used for the ultra-precision grinding of the hard-cutting materials, such as high strength steel and carbonized tungsten, which are characteristics with axisymmetric aspheric surface. Under the priority of accuracy and grinding rigidity to design the key components of multi-axis linked parallel grinding system of aspheric surface, such as high speed grinding spindle, B axis grinding rotary table, clamps and center high adjusting system. Maximum speed of the grinding spindle is 90,000rpm, spindle rotating accuracy is 0.1μm, rotation-angle-accuracy of B axis is , center height adjusting accuracy is 0.1μm, using the system can realize parallel grinding of aspheric surface[1].


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.


2010 ◽  
Vol 135 ◽  
pp. 134-138 ◽  
Author(s):  
Shao Hui Yin ◽  
Heng Ning Tang ◽  
Jian Wu Yu ◽  
Kun Tang ◽  
Feng Jun Chen ◽  
...  

This paper deals with one-point parallel grinding and magnetorheological finishing (MRF) polishing of micro glass lens mould. Firstly,the analysis and experiment of one-point parallel grinding are conducted on micro-aspheric mould with 10mm in diameter , after grinding ,the results show that the form accuracy of the micro aspheric mould are 2.538 μm in PVand 0.645 μm in RMS, also the subsurface damages and residual grinding marks are left ;And then , the magnetorheological finishing experiment is counducted, the form accuracy achieves 0.892 μm in PV and 0.287 μm in RMS ,after finishing, the surface quality was improved.


2010 ◽  
Vol 135 ◽  
pp. 325-330
Author(s):  
Shao Hui Yin ◽  
Ze Biao Wang ◽  
Yu Wang ◽  
Feng Jun Chen ◽  
Jian Wu Yu

This paper reported a deterministic method to predict geometrical interferences between grinding wheel and workpiece on ultra-precision grinding for micro aspherical lens mould. An inclined axis grinding mode controlled by B axis is considered and investigated. For avoiding the interference between the grinding wheel and the workpiece, the relationship of the radius of the grinding wheel should be analyzed in the grinding process. In this paper, a geometrical mathematical model for avoiding interferences between grinding wheel and workpiece is built up, and three interference conditions are analyzed. The maximum diameter of the cylindrical grinding wheel is computed and obtained for grinding axisymmetric aspheric surface.


2014 ◽  
Vol 625 ◽  
pp. 161-166 ◽  
Author(s):  
Thomas Bletek ◽  
Fritz Klocke ◽  
Martin Hünten ◽  
Olaf Dambon

The manufacturing of molds with diffractive structures requires new approaches in terms of grinding wheel geometry and preparation. To be able to manufacture small geometric features such as widths and depths in the micron range on the mold, ideally sharp edged grinding wheels should be used. This paper will present dressing procedures to create sharp edged grinding wheels by using metal alloy blocks. The results and achieved tip radii of the dressed resin bonded and metal bonded fine grained grinding wheels will be presented. Finally, grinding tests of a tungsten carbide mold with a diffractive structure are conducted and the results of the achieved form accuracy and surface roughness are presented.


2011 ◽  
Vol 58-60 ◽  
pp. 1792-1796
Author(s):  
Wei Li ◽  
Yu Jie Fan

Electronic in-process dressing (ELID) grinding will be a main technology of ultra-precision grinding which has been widely adopted to the ultra-precision and high effectively machining of hard and brittle materials. This study puts forward a new environmental friendly bamboo charcoal bonded (BCB) grinding wheel and develops a new ELID grinding fluid. An oxide layer is mostly determined by the electric performance of grinding fluid in the experiment. This paper founds a model to forecast grinding fluid’s electric performance by BP neural network and MATLAB. This method can be used in developing of ELID grinding machining fluid to improve the ELID grinding effect.


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.


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