Chemical influence of different pH-values on ductile mode processing through ultra-precision diamond turning

2016 ◽  
Author(s):  
Marius Doetz ◽  
Olaf Dambon ◽  
Fritz Klocke ◽  
Oliver Faehnle
Keyword(s):  
Diamond Turning ◽  
Ph Values ◽  
Ductile Mode ◽  
Ultra Precision ◽  
Chemical Influence

Development of a Non-Contact Tool Setting System for Precision Diamond Turning

2006 ◽  
Vol 505-507 ◽  
pp. 367-372 ◽  
Author(s):  
Choung Lii Chao ◽  
T.A. Cheng ◽  
D.C. Lou ◽  
Chung Woei Chao
Keyword(s):  
Contact Point ◽  
Diamond Turning ◽  
Optical Diffraction ◽  
Sampling Step ◽  
Error Band ◽  
Sampling Distance ◽  
Tool Shape ◽  
Tool Setting ◽  
Ultra Precision ◽  
Cnc Controller

Precise and efficient tool setting technique and accurate tool shape monitoring are of essential importance in ultra-precision diamond turning operation. The traditional way of tool setting are typically laborious, inefficient and rely heavily on experience. A big part of the tool setting is done by using a contact probe such as LVDT. The contact tool setting station can normally, depending on the resolution of the probes, place the tool tip to within a 1~10μm positioning accuracy. However, it is running the risk of damage the delicate tool tip and has the ambiguity introduced by contact point of tool and touch probe. The optical/non-contact way of setting the tool do have the advantage of not having to touch the tool, but its resolution is limited by the optical diffraction limit and the resolution of the CCD device used (mm/pixel). A non-contact precision tool setting system is developed and built in this study using edge-detection image processing and sub-pixel dividing techniques in conjunction with CNC controller of the precision turning machine to improve the system presently available. Depending on the sampling distance of the images, the error band gets wider when the sampling step becomes larger. In the case of 0.1μm sampling distance the obtained error band was within ±0.1μm and the results showed that tools of different shapes namely round, half-round and sharp tool could all be positioned to within an error band of ±0.1μm by using the developed tool setting system.

scholarly journals Measurement and Compensation of Tool Contour Error Using White Light Interferometry for Ultra-Precision Diamond Turning of Freeform Surfaces

2020 ◽  
Vol 14 (4) ◽  
pp. 654-664 ◽  
Author(s):  
Kodai Nagayama ◽  
◽  
Jiwang Yan
Keyword(s):  
White Light ◽  
High Efficiency ◽  
Diamond Tool ◽  
Microlens Array ◽  
Diamond Turning ◽  
Contour Error ◽  
Form Accuracy ◽  
Freeform Optics ◽  
Ultra Precision ◽  
Quick Measurement

In ultra-precision diamond turning of freeform optics, it is necessary to obtain submicron-level form accuracy with high efficiency. In this study, we proposed a new method for the quick measurement and compensation of tool contour errors to improve the form accuracy of the workpiece. In this method, the nanometer-scale contour error of a diamond tool is quickly and precisely measured using a white light interferometer and then compensated for, before machining. Results showed that the contour of a diamond tool was measured with an error less than 0.05 μm peak-to-valley (P-V) and the feasibility of error compensation was verified through cutting experiments to create a paraboloid mirror and a microlens array. The form error decreased to 0.2 μm P-V regardless of the contour error of the diamond tools when cutting the paraboloid mirror, and that of the microlens array was reduced to 0.15 μm P-V during a single machining step.

Indentation Crack Initiation and Ductile to Brittle Transition Behavior of Fused Silica

2013 ◽  
Vol 797 ◽  
pp. 667-672 ◽  
Author(s):  
Peng Yao ◽  
Wei Wang ◽  
Chuan Zhen Huang ◽  
Jun Wang ◽  
Hong Tao Zhu ◽  
...  
Keyword(s):  
Penetration Depth ◽  
High Efficiency ◽  
Fused Silica ◽  
Load Range ◽  
Brittle Transition ◽  
Ductile Mode ◽  
Indentation Crack ◽  
Ultra Precision ◽  
Ductile To Brittle Transition ◽  
Brittle Mode

To provide a fundamental knowledge for the high efficiency grinding and ultra-precision grinding of fused silica, ductile mode and brittle mode material removal mechanisms were investigated by conducting micro/nanoindentation experiments in the range of 4.9 mN - 1960 mN. Before observing cracks and determining the ductile to brittle transition penetration depth, the samples were etched with hydrofluoric acid to expose cracks. The typical damage morphology of fused silica was discussed by observing the surface and cross-section of indentations, and the depth of SSD was found to be determined by the cone cracks or borderline cracks in the different load range. The ductile to brittle transition penetration depth of fused silica under Vickers indentation was 180 nm.

scholarly journals Simulation and Experimental Study on the Surface Generation Mechanism of Cu Alloys in Ultra-Precision Diamond Turning

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 573
Author(s):  
Zhang ◽  
Guo ◽  
Chen ◽  
Fu ◽  
Zhao
Keyword(s):  
Tool Wear ◽  
Diamond Tool ◽  
Surface Characteristics ◽  
Diamond Turning ◽  
Generation Mechanism ◽  
Surface Generation ◽  
Machining Parameters ◽  
Nose Radius ◽  
Cu Alloys ◽  
Ultra Precision

The surface generation mechanism of the Cu alloys in ultra-precision diamond turning is investigated by both simulation and experimental methods, where the effects of the cutting parameters on the surface characteristics are explored, including the workpiece spindle speed, the cutting depth, the feed rate and the nose radius of the diamond tool. To verify the built model, the cutting experiments are conducted at selected parameters, where the causes of the error between the simulation and the machining results are analyzed, including the effects of the materials microstructure and the diamond tool wear. In addition, the nanometric surface characteristics of the Cu alloys after the diamond turning are identified, including the finer scratching grooves caused by the tool wear, the formation of the surface burs and the adhesion of graphite. The results show that the built model can be basically used to predict the surface topography for the selection of the appropriate machining parameters in the ultra-precision diamond turning process.

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