Analysis of Surface Roughness and Waviness During Diamond Turning of Polycarbonate

In the globally competitive environment, surface roughness and finer tolerances are becoming stringent and certainly most critical for optical components. The aim of this study is to determine the effects of diamond turning process parameters on surface finish when diamond turning RSA 443 alloy having high silicon content. This alloy is a new grade of aluminum that has a potential to be used for production of various optical components. The experiments were conducted based on the Box-Behnken design with three diamond-turning parameters varied at three levels. A mathematical regression model was developed for predicting surface roughness. Further, the analysis of variance was used to analyze the influence of cutting parameters and their interaction in machining. The developed prediction model reveals that cutting speed and feed rate are the most dominant diamond turning factors influencing surface roughness.

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Review of single-point diamond turning process in terms of ultra-precision optical surface roughness

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-019-04700-3 ◽

2019 ◽

Vol 106 (5-6) ◽

pp. 2167-2187 ◽

Cited By ~ 8

Author(s):

Shahrokh Hatefi ◽

Khaled Abou-El-Hossein

Keyword(s):

Surface Roughness ◽

Single Point ◽

Diamond Turning ◽

Optical Surface ◽

Turning Process ◽

Ultra Precision

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Fuzzy logic-based modeling and analysis of surface roughness, electrostatic charge, and material removal rate in ultrahigh precision diamond turning of rigid contact lens polymer

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705719850602 ◽

2019 ◽

pp. 089270571985060

Author(s):

Muhammad Mukhtar Liman ◽

Khaled Abou-El-Hossein ◽

Lukman Niyi Abdulkadir

Keyword(s):

Surface Roughness ◽

Fuzzy Logic ◽

Material Removal Rate ◽

Contact Lens ◽

Material Removal ◽

Removal Rate ◽

Electrostatic Charge ◽

High Accuracy ◽

Diamond Turning ◽

Optical Manufacturing

Due to increasing demand for high accuracy and high-quality surface finish in optical industry, contact lens manufacturing requires reliable models for predicting surface roughness (Ra) which plays a very important role in the optical manufacturing industry. In this study, a Nanoform 250 ultra-grind turning machine was used for machining, while cutting speed, feed rate, and the depth of cut (with values selected to cover a wide range based on the literature) were considered as the machining parameters for a diamond turned rigid polymethylmethacrylate (PMMA) contact lens polymer. Turning experiments were designed and conducted according to Box–Behnken design which is a response surface methodology technique. Fuzzy logic-based artificial intelligence method was employed to develop an electrostatic charge (ESC), Ra, and material removal rate (MRR) prediction models. The accuracy and predictive ability of the fuzzy logic model was then judged by considering an average percentage error between experimental values and fuzzy logic predictions. Further, a comparative evaluation of experiments and fuzzy logic approach showed that the average errors of ESC, Ra, and MRR using fuzzy logic system were in tandem with experimental results. Hence, the developed fuzzy logic rules can be effectively utilized to predict the ESC, Ra, and MRR of a rigid PMMA contact lens polymers in automated optical manufacturing environments for high accuracy and computational cost.

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Study on the control of surface roughness in single point diamond turning

10.1117/12.975196 ◽

2012 ◽

Cited By ~ 1

Author(s):

Honghuai Xu ◽

Xiangchao Zhang ◽

Min Xu ◽

Xufeng Li

Keyword(s):

Surface Roughness ◽

Single Point ◽

Diamond Turning

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Ultrasonic Assisted Diamond Turning of Hardened Steel for Mould Manufacturing

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.516.437 ◽

2012 ◽

Vol 516 ◽

pp. 437-442 ◽

Cited By ~ 9

Author(s):

Benjamin Bulla ◽

Fritz Klocke ◽

Olaf Dambon ◽

Martin Hünten

Keyword(s):

Surface Roughness ◽

Tool Wear ◽

Diamond Tool ◽

Spherical Geometry ◽

Diamond Turning ◽

Optical Surface ◽

Turning Process ◽

Shape Accuracy ◽

Ultrasonic Assisted ◽

Innovative Potential

Diamond turning of steel parts is conventionally not possible due to the high tool wear. However this process would enable several different applications with high economical innovative potential. One technology that enables the direct manufacturing of steel components with monocrystalline diamond is the ultrasonic assisted diamond turning process. This technology has been investigated over the years within the Fraunhofer IPT and is now commercialized by its spin-off company son-x. Surface roughness in the range of Ra < 5 nm can be achieved and the diamond tool wear is reduced by a factor of 100 or higher. In order to prove the industrial suitability of the process, two aspherical shapes and one large spherical geometry have been manufactured. The possible form accuracies and surface roughness values will be described in this paper, as well as the tool wear. The goal was to achieve optical surface roughness and a shape accuracy below 300 nm.

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Development of a Small Rotary Multi-Jet Abrasive Fluid Jet Polishing Tool

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.625.140 ◽

2014 ◽

Vol 625 ◽

pp. 140-148 ◽

Cited By ~ 2

Author(s):

Assefa Asmare Tsegaw ◽

Fang Jung Shiou

Keyword(s):

Surface Roughness ◽

Optical Glass ◽

Fluid Pressure ◽

Head Rotation ◽

Angular Speed ◽

Diamond Turning ◽

Optimal Parameters ◽

Optical Glasses ◽

Control Factors ◽

Polishing Tool

Most optical glasses are in recent years being manufactured by diamond turning processes which has certainly modernized the field of production of optics. Confines of diamond turning for both form and surface finish accuracy have not been reached, yet. In advent of contemporary technology, high precision finishing techniques are of great concern and the need of present industrialized-scenario. This paper presents the development of a small rotary multi-jet abrasive fluid jet polishing tool for use in polishing of optical glasses. The newly designed and manufactured tool has relative angular speed with respect to the spindle of machining centre and is capable of polishing at micro levels. The paper also investigates the optimal polishing parameters for selected, crown optical glass based on experiments conducted using Taguchi’s experimental method. According to the possible number of control factorsL18orthogonal array was used. ANOVA analysis was carried out to determine the main factors which would affect the surface roughness significantly. Consequently, a 2.5 μm size of Al2O3abrasive, 10wt% abrasive concentration, 40 rpm of polishing head rotation, 6 numbers of nozzles, 6 kg/cm2of fluid pressure, 45minuet of polishing time and 40% of step over have been found to be the optimal parameters. It was observed that about 97.22% improvements on surface roughness; Ra, from 0.360 μm to 0.010 μm has been achieved using the optimal parameters. In addition to this; rotation of polishing head, applied fluid pressure and polishing time were found to have significant effect on surface roughness improvement.

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Study, analysis, and characterization of ultra-precision diamond tools for single-point diamond turning

Journal of Micromanufacturing ◽

10.1177/2516598420965338 ◽

2020 ◽

pp. 251659842096533

Author(s):

RamaGopal V. Sarepaka ◽

Sivasakthi Balan ◽

Somaiah Doodala ◽

Rakesh Singh Panwar ◽

D. Rajendra Kotaria

Keyword(s):

Surface Roughness ◽

Diamond Tool ◽

Single Point ◽

Quality Parameters ◽

Diamond Turning ◽

Radius Of Curvature ◽

Tool Selection ◽

Diamond Tools ◽

Surface Irregularities ◽

Ultra Precision

In multiple applications of advanced instrumentation, single-point diamond turning (SPDT) is a popular and effective process to generate novel surfaces with nanometric surface roughness and sub-micron surface irregularities, albeit at a high cost. In SPDT, precision diamond tooling contributes significantly to the process cost escalation. Hence, for SPDT, it is vital to have an optimal precision diamond tool deployment. In this article, details of comprehensive precision diamond tool selection and tool characterization are discussed. Three makes of selected ultra-precision diamond (UPD) tools and standard diamond tools (of a global make), designated as CFT, are considered for this study. In this tool bench-marking exercise, the fabrication of Cu–Be alloy predesigned precision components (PDPCs) of a critical geometry is selected. UPD and CFT tools are deployed to fabricate (under similar machining-metrology conditions) the PDPCs. These diamond tools are evaluated in terms of the quality parameters (variation in radius of curvature, form error, and surface roughness) of the workpieces. Further, to explore the progressive wear of these tools, multiple machining cycles are conducted on these workpieces, and their quality parameters are analyzed. Thus, the precision diamond tools of three makes are benchmarked against the CFT tool. Based on the final outcome of this analysis, suitable recommendations are provided to precision diamond tool manufacturers to improve their product in terms of performance and optimized costs to meet the ever-growing tooling demands of the SPDT community.

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