Optimization of Nano-Topography Distribution by Compensation Grinding

Optical surfaces are required to have high form accuracy and smoothness. The form accuracy must be below 50 nm. Form accuracy is currently on the order of several tens of nanometers or less; however, further improvement is required. To improve form accuracy, compensation grinding is performed based on form measurement results. However, when the form error is small, a small periodical waviness occurs on the ground surface, which is known as nano-topography. This waviness cannot be compensated for using conventional compensation methods because the nano-topography distributions are not reproducible. A previous study showed that grinding conditions affect the spatial frequency of nano-topography. Therefore, in this study, optimum grinding conditions are estimated from the view point of nano-topography distributions, and the grinding conditions are compensated to optimize these distributions.

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Polishing Characteristics of ELID-Ground Surface of Nano Precision Optical Elements

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.291-292.365 ◽

2005 ◽

Vol 291-292 ◽

pp. 365-370 ◽

Cited By ~ 2

Author(s):

Wei Min Lin ◽

Hitoshi Ohmori ◽

T. Suzuki ◽

Yoshihiro Uehara ◽

Shinya MORITA

Keyword(s):

Ground Surface ◽

Diamond Wheel ◽

Fused Silica ◽

Optical Elements ◽

Form Accuracy ◽

High Form ◽

Ultra Precision ◽

Fundamental Research ◽

Aspherical Mirrors ◽

Polishing Tool

This paper describes an ultra precision polishing method of aspherical mirrors, and the fundamental research on polishing characteristics. The aspherical mirrors with a diameter of about 30mm made by fused silica glass and CVD-SiC were ELID (electrolytic in-process dressing)-ground to high form accuracy with #4000 cast iron bonded diamond wheel, and then polished with a small polishing tool. As the result, final surface roughness of 1.4nmRa and form accuracy of 1.2 μm was obtained.

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Error Compensation in One-Point Inclined-Axis Nanogrinding Mode for Small Aspheric Mould

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.97-101.4206 ◽

2010 ◽

Vol 97-101 ◽

pp. 4206-4212 ◽

Cited By ~ 1

Author(s):

Shao Hui Yin ◽

Feng Jun Chen ◽

Yu Wang ◽

Yu Feng Fan ◽

Yong Jian Zhu ◽

...

Keyword(s):

Error Compensation ◽

Single Point ◽

Ground Surface ◽

Compensation Method ◽

Grinding Wheel ◽

Form Error ◽

Profile Data ◽

Profile Error ◽

Form Accuracy ◽

Setting Error

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.

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On-Machine Precision Form Truing and In-Situ Measurement of Resin-Bonded Spherical Diamond Wheel

Applied Sciences ◽

10.3390/app10041483 ◽

2020 ◽

Vol 10 (4) ◽

pp. 1483 ◽

Cited By ~ 2

Author(s):

Jinhu Wang ◽

Qingliang Zhao ◽

Chunyu Zhang ◽

Bing Guo ◽

Julong Yuan

Keyword(s):

Surface Profile ◽

Ground Surface ◽

Diamond Wheel ◽

In Situ Measurement ◽

Coarse Grained ◽

Alignment Error ◽

Machine Precision ◽

Form Accuracy ◽

Measurement Results

The resin-bonded spherical diamond wheel is widely used in arc envelope grinding, where the demands for form accuracy are high and the form truing process is challenging. In this paper, on-machine precision form truing of the resin-bonded spherical diamond wheel is accomplished by using a coarse-grained diamond roller, and in-situ measurement of the form-truing error is conducted through a laser scan micrometer. Firstly, a novel biarc curve-fitting method is proposed based on the in-situ measurement results to calculate the alignment error between the diamond roller and the spherical diamond wheel. Then, on-machine precision form truing of a D46 resin-bonded spherical diamond wheel is completed after alignment error compensation. The in-situ measurement results show that the low-frequency form-truing error is approximately 5 μm. In addition, the actual form-trued diamond wheel has been employed in grinding a test specimen, and the resulting form accuracy is approximately 1.6 μm without any compensation. The ground surface profile shared similar characteristics with the roller-trued diamond wheel profile, confirming that the diamond roller truing and in-situ measurements methods are accurate and feasible.

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Optimization of Grinding Conditions in Non-Axisymmetric Aspherical Grinding

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1017.109 ◽

2014 ◽

Vol 1017 ◽

pp. 109-113 ◽

Cited By ~ 1

Author(s):

Nobuhito Yoshihara ◽

Tomoharu Nakagawa ◽

Naohiro Nishikawa ◽

Masahiro Mizuno

Keyword(s):

Surface Roughness ◽

Smooth Surface ◽

Ground Surface ◽

Precision Grinding ◽

Form Accuracy ◽

Grinding Conditions

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.

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Ultra-High Speed Grinding Using a CBN Wheel for a Mirror-Like Surface Finish

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.291-292.67 ◽

2005 ◽

Vol 291-292 ◽

pp. 67-72 ◽

Cited By ~ 2

Author(s):

M. Ota ◽

T. Nakayama ◽

K. Takashima ◽

H. Watanabe

Keyword(s):

Surface Finish ◽

High Speed ◽

High Efficiency ◽

Ground Surface ◽

Machining Process ◽

Grinding Wheel ◽

Cbn Wheel ◽

Ultra High Speed ◽

High Speed Grinding ◽

Grinding Conditions

There are strong demands for a machining process capable of reducing the surface roughness of sliding parts, such as auto parts and other components, with high efficiency. In this work, we attempted to grind hardened steel to a mirror-like surface finish with high efficiency using an ultra-high speed grinding process. In the present study, we examined the effects of the work speed and the grinding wheel grain size in an effort to optimize the grinding conditions for accomplishing mirror-like surface grinding with high efficiency. The results showed that increasing the work speed, while keeping grinding efficiency constant, was effective in reducing the work affected layer and that the grinding force of a #200 CBN wheel was lower than that of a #80 CBN wheel. Based on these results, a high-efficiency grinding step with optimized grinding conditions was selected that achieved excellent ground surface quality with a mirror-like finish.

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Form Accuracy of Optical Mould Inserts Made from Rapidly Solidified Aluminium Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.828-829.62 ◽

2015 ◽

Vol 828-829 ◽

pp. 62-68

Author(s):

Khaled Abou-El-Hossein

Keyword(s):

High Precision ◽

Surface Finish ◽

Single Point ◽

Cutting Parameters ◽

Diamond Turning ◽

Machining Parameters ◽

Optical Surface ◽

Form Accuracy ◽

Optical Surfaces ◽

Rapidly Solidified

Plastic optical components and lenses produced in mass quantities are usually manufactured using high-precision plastic injection technology. For that, high-precision plastic moulds with aluminium optical inserts made with extremely high dimension accuracy and high optical surface quality are used. Ultra-high precision single-point diamond turning have been successfully used in shaping optical mould inserts from various aluminium grades such as traditional 6061. However, extreme care should be taking when selecting machining parameters in order to produce optically valid surfaces before premature tool wear takes place especially when the machined optical materials has inadequate machining database. The current experimental study looks at the effect of cutting conditions on optical surfaces made from aluminium. The study embarks on helping establish some diamond machining database that helps engineers select the most favourable cutting parameters. The papers reports on the accuracy and surface finish quality received on an optical surface made on mould inserts from a newly developed aluminium alloy. Rapidly solidified aluminium (RSA) grades have been developed recently to address the various problems encountered when being cut by single-point diamond turning operation. The material is characterised by its extremely fine grained microstructure which helps extend the tool life and produce optical surfaces with nanometric surface finish. It is found the RSA grades can be successfully used to replace traditional optical aluminium grades when making optical surfaces. Surface finishes of as low as 10 nanometres and form accuracy of less than one micron can be achieved on RSA.

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COMPARISON OF EXPERIMENTALLY MEASURED AND SIMULATED WORKPIECE AND GRINDING WHEEL TOPOGRAPHY USING A NEW DRESSING MODEL

Transactions of the Canadian Society for Mechanical Engineering ◽

10.1139/tcsme-2016-0001 ◽

2016 ◽

Vol 40 (1) ◽

pp. 1-17 ◽

Cited By ~ 1

Author(s):

Abdalslam Darafon ◽

Andrew Warkentin ◽

Robert Bauer

Keyword(s):

Surface Finish ◽

Metal Removal ◽

Ground Surface ◽

Cutting Edge ◽

Edge Density ◽

Grinding Wheel ◽

Workpiece Surface ◽

Wheel Topography ◽

Grinding Wheel Topography ◽

Grinding Conditions

This paper presents a new empirical model of the dressing process in grinding which is then incorporated into a 3D metal removal computer simulator to numerically predict the ground surface of a workpiece as well as the dressed surface of the grinding wheel. The proposed model superimposes a ductile cutting dressing model with a grain fracture model to numerically generate the resulting grinding wheel topography and workpiece surface. Grinding experiments were carried out using “fine”, “medium” and “coarse” dressing conditions to validate both the predicted wheel topography as well as the workpiece surface finish. For the grinding conditions used in this research, it was observed that the proposed dressing model is able to accurately predict the resulting workpiece surface finish for all dressing conditions tested. Furthermore, similar trends were observed between the predicted and experimentally-measured grinding wheel topographies when plotting the cutting edge density, average cutting edge width and average cutting edge spacing as a function of depth for all dressing conditions tested.

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Simulation and analysis of optical imaging systems including real freeform components

Advanced Optical Technologies ◽

10.1515/aot-2018-0065 ◽

2019 ◽

Vol 0 (0) ◽

Cited By ~ 2

Author(s):

Johannes Stock ◽

Matthias Beier ◽

Johannes Hartung ◽

Sebastian Merx ◽

Herbert Gross

Keyword(s):

Experimental Data ◽

Spatial Frequency ◽

Optical System ◽

System Performance ◽

Imaging Systems ◽

Optical Surfaces ◽

Surface Imperfections ◽

Performance Predictions ◽

Alignment Errors ◽

Holistic Description

Abstract In recent years, the precision of the manufacturing process for optical surfaces has improved tremendously. As a result, freefrom surfaces have become more attractive options for imaging applications with increased accuracy requirements. However, with regards the integration into an optical system, performance is often limited due to surface imperfections, such as mid-spatial frequency errors and alignment errors. This demonstrates the need for a more holistic description of systems, including multiple freeform components, which enable performance predictions based on the system as a whole. In this work, a solution for such a simulation is presented and verified by a comparison with the experimental data. This procedure not only predicts system performance but also supports tolerancing and easier alignment.

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Optimization of Cutting Edge Truncation Depth for Ultrasonically Assisted Grinding to Finish Mirror Surface

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.76-78.88 ◽

2009 ◽

Vol 76-78 ◽

pp. 88-93 ◽

Cited By ~ 3

Author(s):

Keisuke Hara ◽

Hiromi Isobe ◽

Akira Kyusojin

Keyword(s):

Ground Surface ◽

Optimization Techniques ◽

Cutting Edge ◽

Mirror Surface ◽

Skilled Workers ◽

Ultrasonic Oscillation ◽

Oscillation Effect ◽

Grinding Conditions ◽

Grinding Technique ◽

Face Grinding

High precision mold grinding technique to obtain mirror surface is required which realizes minimization or omission of final polishing by skilled workers. In the previous reports, ultrasonic diamond grinding experiments were carried out to confirm ultrasonic oscillation effect for die steel face grinding. Smooth and glossy surfaces were obtained successfully and little abrasive worn out was found. In the above techniques require cutting edge truncation because the cutting edge shape of a tool affects the ground surface resulting from transcription of cutting edge. This paper describes optimization techniques for the cutting edge truncation of diamond electroplated tools which are used in ultrasonically assisted grinding. Experiments were carried out to confirm truncation effects on the ground surface and grinding force. It was confirmed that roughness was proportional to inverse of thrust force. Minimum roughness in grinding conditions were estimated from the proportional diagrams. The minimum roughness shows limit of roughness on an each grinding condition.

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