Ultra-precision Grinding of Binderless Tungsten Carbide Aspheric Mold

2014 ◽  
Vol 50 (13) ◽  
pp. 190 ◽  
Author(s):  
Bing GUO
Keyword(s):  
Tungsten Carbide ◽  
Precision Grinding ◽  
Ultra Precision

Ultra Precision Grinding of Wafer Scale

2012 ◽  
Vol 516 ◽  
pp. 257-262
Author(s):  
Martin Hünten ◽  
Fritz Klocke ◽  
Olaf Dambon ◽  
Benjamin Bulla
Keyword(s):  
Tungsten Carbide ◽  
Surface Topography ◽  
Precision Grinding ◽  
Wafer Scale ◽  
Advantages And Disadvantages ◽  
Grinding Processes ◽  
Ultra Precision ◽  
Grinding Tool ◽  
Glass Optics ◽  
Grinding Machine

Manufacturing moulds for the wafer-scale replication of precision glass optics sets new demands in terms of grinding tool lifetime and the processes to be applied. This paper will present different approaches to grinding processes and kinematics to machine wafer-scale tungsten carbide moulds with diameters of up to 100 mm and more than 100 single aspheric cavities, each featuring form accuracies in the micron range. The development of these processes will be described and advantages and disadvantages of the approaches derived from practical tests performed on an ultra precision grinding machine (Moore Nanotech 350FG) will be discussed. Finally, a comparison between the developed processes is made where achieved form accuracies and surface topography are analyzed.

Influence of Ultrasonic Assisted Processing on the Ductility of Binderless Tungsten Carbide

2014 ◽  
Vol 625 ◽  
pp. 587-592 ◽  
Author(s):  
Benjamin Bulla ◽  
Fritz Klocke ◽  
Olaf Dambon
Keyword(s):  
Tungsten Carbide ◽  
Diamond Turning ◽  
Manufacturing Technology ◽  
Cutting Process ◽  
Precision Grinding ◽  
Ultrasonic Assisted ◽  
Ultra Precision ◽  
High Predictability ◽  
Grinding Technique

For the production of mould inserts for precision glass moulding, the ultra precision grinding technique with a subsequent manual polishing operation is typically applied. These processes are time consuming and have a relatively low reproducibility. An alternative manufacturing technology, with a high predictability and efficiency, which additionally allows a higher geometrical flexibility, is the diamond turning technique. In addition the ultrasonic assisted ultra precision cutting process has already proven its potential for machining difficult-to-cut materials, such as steel and glass. By applying the ultrasonic assistance, the classic constraints of the process can be widened significantly. In this publication the process is applied on binderless, nanocrystalline tungsten carbide.

Dressing of Grinding Wheels for Ultra Precision Grinding of Diffractive Structures in Tungsten Carbide Molds

2014 ◽  
Vol 625 ◽  
pp. 161-166 ◽  
Author(s):  
Thomas Bletek ◽  
Fritz Klocke ◽  
Martin Hünten ◽  
Olaf Dambon
Keyword(s):  
Tungsten Carbide ◽  
Grinding Wheel ◽  
Geometric Features ◽  
Grinding Wheels ◽  
Precision Grinding ◽  
Form Accuracy ◽  
Fine Grained ◽  
Diffractive Structure ◽  
Ultra Precision ◽  
Diffractive Structures

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.

Precision Grinding of Structured Tungsten Carbide Mold

2012 ◽  
Vol 497 ◽  
pp. 15-19 ◽  
Author(s):  
Hirofumi Suzuki ◽  
Tatsuya Furuki ◽  
Mutsumi Okada ◽  
Yutaka Yamagata ◽  
Shinya MORITA
Keyword(s):  
Tungsten Carbide ◽  
Power Efficiency ◽  
Fresnel Lens ◽  
Rare Metal ◽  
Diamond Wheel ◽  
Precision Grinding ◽  
Form Accuracy ◽  
Molding Method ◽  
Grinding Method ◽  
Glass Lens

Demands of glass Fresnel lens is increasing in solar panel in order to increase power efficiency. Glass lens is usually molded by glass molding method with tungsten carbide molds. In this study, large Fresnel lens molds made of tungsten carbide are tested to be ground by simultaneous 2-axis (Y, Z) controlled grinding method. The resinoid bonded diamond wheel was trued with a rare metal truer to improve the sharpness of the wheel edge. In the grinding test of the tungsten carbide mold, a form accuracy of less than 0.8 μm P-V and surface roughness of 18 nm Rz were obtained, and it is clarified that the proposed grinding method is useful for the Fresnel grinding.

Study on Single-Plane Biaxial Balance Monitor System in ULTRA-Precision Grinding

2006 ◽  
Vol 304-305 ◽  
pp. 251-255
Author(s):  
L. Zheng ◽  
Yin Biao Guo ◽  
Z.Z. Wang
Keyword(s):  
Mutual Influence ◽  
Machining Accuracy ◽  
Monitor System ◽  
Machining Parameters ◽  
Precision Grinding ◽  
Single Plane ◽  
Workpiece Surface ◽  
Surface Error ◽  
Vibration Data ◽  
Ultra Precision

This paper puts forward an intelligent single-plane biaxial balance monitor system, which is used in ultra-precision grinding. It adopts the method of single-plane balance correction for the vibration of wheel and workpiece. And this system can also be used for integral balance. For ultra-precision grinding, caused by the mutual influence of the vibration of wheel and workpiece, there will be a ripple on the workpiece surface, which is mainly influenced by the frequency ratio of wheel to workpiece, the feed rate and the vibration of wheel and workpiece. This system can improve the machining accuracy, reduce the surface error of workpiece and appraise the integrated machining result, by analyzing the vibration data of wheel and workpiece and adjusting machining parameters.

Improvement of grinding performance in ultra-precision grinding of lens mould by the help of megasonic coolant

2006 ◽  
Vol 9 (1/2) ◽  
pp. 79 ◽  
Author(s):  
Katsutoshi Tanaka ◽  
Masahiko Fukuta ◽  
Kiyoshi Suzuki ◽  
Manabu Iwai ◽  
Tetsutaro Uematsu ◽  
...  
Keyword(s):  
Precision Grinding ◽  
Grinding Performance ◽  
Ultra Precision

Machined Surface Characteristics and Removal Mechanism of Soft and Brittle Solids

2010 ◽  
Vol 447-448 ◽  
pp. 183-187 ◽  
Author(s):  
Zhen Yu Zhang ◽  
Rudy Irwan ◽  
Han Huang
Keyword(s):  
Surface Characteristics ◽  
Abrasive Machining ◽  
Precision Grinding ◽  
Machined Surface ◽  
Brittle Solids ◽  
The Coefficient Of Friction ◽  
Ultra Precision ◽  
Ductile Removal ◽  
Fracture Features ◽  
Free Abrasive

Surface characteristics of CZT wafers machined using wire sawing, free abrasives lapping and polishing and ultra-precision grinding were investigated. Wire sawing resulted in the removal of material in both ductile and brittle regimes, but both polishing and grinding led to a ductile removal. The grinding produced very smooth surfaces free of embeddings and scratches, which is thus considered to have better machinability than the free abrasive machining. The nanoindentation and nanoscratch on MCT wafers at nanometric scales resulted in considerable plastic deformation, but no fracture features. The hardness of the MCT wafer was 500 to 550 MPa, and the coefficient of friction was particularly high, ranging from 0.45 to 0.55.

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.

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