Investigation Of Cutting Mechanics In Single Point Diamond Turning Of Silicon

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Investigation Of Cutting Mechanics In Single Point Diamond Turning Of Silicon

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Author : Amir Mir
language : en
Publisher:
Release Date : 2016

Investigation Of Cutting Mechanics In Single Point Diamond Turning Of Silicon written by Amir Mir and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.

As a kind of brittle material, silicon will undergo brittle fracture at atmospheric pressure in conventional scale machining. Studies in the last two decades on hard and brittle materials including silicon, germanium, silicon nitride and silicon carbide have demonstrated ductile regime machining using single point diamond turning (SPDT) process. The mirror-like surface finish can be achieved in SPDT provided appropriate tool geometry and cutting parameters including feed rate, depth of cut and cutting speed are adopted.The research work in this thesis is based on combined experimental and numerical smoothed particle hydrodynamics (SPH) studies to provide an inclusive understanding of SPDT of silicon. A global perspective of tool and workpiece condition using experimental studies along with localized chip formation and stress distribution analysis using distinctive SPH approach offer a comprehensive insight of cutting mechanics of silicon and diamond tool wear. In SPH modelling of SPDT of silicon, the distribution of von Mises and hydrostatic stress at incipient and steady-state was found to provide the conditions pertinent to material failure, phase transformation, and ductile mode machining. The pressure-sensitive Drucker Prager (DP) material constitutive model was adopted to predict the machining response behaviour of silicon during SPDT. Inverse parametric analysis based on indentation test was carried out to determine the unknown DP parameters of silicon by analysing the loading-unloading curve for different DP parameters. A very first experimental study was conducted to determine Johnson-Cook (J-C) model constants for silicon. High strain rate compression tests using split Hopkinson pressure bar (SHPB) test as well as quasi-static tests using Instron fatigue testing machine were conducted to determine J-C model constants.The capability of diamond tools to maintain expedient conditions for high-pressure phase transformation (HPPT) as a function of rake angle and tool wear were investigated experimentally as well as using SPH approach. The proportional relationship of cutting forces magnitude and tool wear was found to differ owing to wear contour with different rake angles that influence the distribution of stresses and uniform hydrostatic pressure under the tool cutting edge. A new quantitative evaluation parameter for the tool wear resistance performance based on the cutting distance was also proposed. It was also found that the machinability of silicon could be improved by adopting novel surface defect machining (SDM) method.The ductile to brittle transition (DBT) with the progressive tool wear was found to initiate with the formation of lateral cracks at low tool wear volume which transform into brittle pitting damage at higher tool edge degradation. A significant variation in resistance to shear deformation as well as position shift of the maximum stress values was observed with the progressive tool wear. The magnitude and distribution of hydrostatic stress were also found to change significantly along the cutting edge of the new and worn diamond tools.

Materials Characterisation And Mechanism Of Micro Cutting In Ultra Precision Diamond Turning

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Author : Sandy Suet To
language : en
Publisher: Springer
Release Date : 2017-05-23

Materials Characterisation And Mechanism Of Micro Cutting In Ultra Precision Diamond Turning written by Sandy Suet To and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-05-23 with Technology & Engineering categories.

This book presents an in-depth study and elucidation on the mechanisms of the micro-cutting process, with particular emphasis and a novel viewpoint on materials characterization and its influences on ultra-precision machining. Ultra-precision single point diamond turning is a key technology in the manufacture of mechanical, optical and opto-electronics components with a surface roughness of a few nanometers and form accuracy in the sub-micrometric range. In the context of subtractive manufacturing, ultra-precision diamond turning is based on the pillars of materials science, machine tools, modeling and simulation technologies, etc., making the study of such machining processes intrinsically interdisciplinary. However, in contrast to the substantial advances that have been achieved in machine design, laser metrology and control systems, relatively little research has been conducted on the material behavior and its effects on surface finish, such as the material anisotropy of crystalline materials. The feature of the significantly reduced depth of cut on the order of a few micrometers or less, which is much smaller than the average grain size of work-piece materials, unavoidably means that conventional metal cutting theories can only be of limited value in the investigation of the mechanisms at work in micro-cutting processes in ultra-precision diamond turning.

Surface Generation In Ultra Precision Diamond Turning

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Author : W. B. Lee
language : en
Publisher: John Wiley & Sons
Release Date : 2003-02-07

Surface Generation In Ultra Precision Diamond Turning written by W. B. Lee and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003-02-07 with Technology & Engineering categories.

An Engineering Research Series title. One of the remarkable achievements of modern manufacturing techniques is the ability to achieve nano-metre surface finishes. Ultraprecision machining based on single-point diamond turning (SPDT) is a very important technique in the manufacture of high-precision components where surface finish is critical. Complex optical surfaces, for example, can be produced without the need for post-machining polishing. This book focuses on the aspect of modelling nano-surface generation in ultra precision SPDT. Potential industrial applications in the prediction of surface quality, the process optimization, and precision mould manufacturing are also studies. The essential differences between single-point diamond turning and conventional machining are described. The history and technology of single-point diamond turning are presented and single chapters emphasize the related metrology and cutting mechanics. Important aspects of surface generation are also discussed. Features of the text are the sound approach, systematic mathematical modelling, and computer-aided simulation of surface generation in the development of surfaces exhibiting nano-surface qualities. TOPICS COVERED INCLUDE: Fundamentals of ultra-precision diamond turning technology Cutting mechanics and analysis of microcutting force variation Mechanisms of surface generation Characterization and modelling of nano-surface generation Computer-aided simulation of nano-surface generation Diamond turning of aspheric optics. Based upon the extensive experience of the authors Surface Generation in Ultra-precision Diamond Turning: Modelling and Practices will be of interest to engineers, scientists, and postgraduate students.

Numerical Simulation Of Single Point Diamond Turning

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Author : Yeong Chia Teoh
language : en
Publisher:
Release Date : 2009

Numerical Simulation Of Single Point Diamond Turning written by Yeong Chia Teoh and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with Machine-tools categories.

A coupled thermo-mechanical plane-strain large-deformation orthogonal cutting finite element model is presented in this thesis by using the ABAQUS finite element code to simulate the cutting mechanics of OFHC Copper in Single-Point Diamond Turning (SPDT). The simulations concern the study of stress and strain imparted in the workpiece during metal cutting process. Round edge cutting tool is used in this study since the tool edge radius has comparable size to the uncut chip thickness in SPDT. The tool is treated as perfectly rigid body where the cutting conditions and boundary conditions are prescribed at a reference point. Workpiece material is modeled as thermo-visco-plastic material that is considered dependent upon the plastic strain, the plastic strain rate and temperature variations. The flow stress calculation is expressed as the form of Johnson-Cook's constitutive equation that take into account the effect of the large strain, strain-rate and temperature associated with cutting on the material properties. To reduce computational time and cost, the workpiece is discretized by nonuniform mesh. Mesh distortion problem due to large deformation in front of tool tip during cutting simulation is solved using pure deformation technique. A more realistic and physically based chip formation can be achieved by using this method. Chip formation yield from the finite element method simulation of OFHC Copper is observed and it revealed good chip morphology that agrees well with the previous studies. The model is validated with the published report based on Von Mises Stress and found to be in good agreement also. This model is useful to economically analyze SPDT and thus to meet the need for improve productivity and quality of machining operations in SPDT.

Investigation Of The Optical Effects Of Single Point Diamond Machined Surfaces And The Applications Of Micro Machining

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Author : Lei Li
language : en
Publisher:
Release Date : 2009

Investigation Of The Optical Effects Of Single Point Diamond Machined Surfaces And The Applications Of Micro Machining written by Lei Li and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with Diamond turning categories.

Abstract: The ultraprecision Single Point Diamond Turning (SPDT) technology has been developed for over 40 years and has been successfully applied to numerous fields. At present, the ultraprecision single point diamond turning technology already expanded to Single Point Diamond Machining (SPDM) technology, which includes several related processes in addition to the more conventional single point diamond turning. The other related processes are Fast Tool Servo (FTS), Slow Tool Servo (STS), broaching, and fly cutting. Though this technology has many notable merits, for example it can achieve micro meter or even sub micron form accuracy and nano meter surface roughness, there still has some drawbacks. One of the objectives of this research is to investigate one of these drawbacks, the diffraction and scattering of the ultraprecision single point diamond machined surfaces. Another objective is to extend the application of the SPDM by developing new design and new machining processes for freeform micro devices used in optical, mechanical, electronic, and biomedical fields. The mechanism and model of the ultraprecision single point diamond turning and micro cutting were first reviewed and discussed. The related subjects to the SPDT and micro cutting were also involved. The optical effects of diamond machined surfaces were studied. The diffraction and scattering generated from the diamond machined surfaces was analytically and experimentally studied. The influences from machining parameters, such as tool mark spacing, feedrate, spindle speed, tool radius, tool condition and different diamond machining process were considered. An empirical relationship between the machining conditions and the first order diffraction from the diamond machined surfaces was setup. This model can be used to select optimal machining conditions for diamond machining process. The design, machining and testing of microlens arrays by using SPDM process were introduced. Two microlens array examples were given. One is a 5 by 5 matrix arranged concave microlens array on flat brass substrate. The other one is a circular arranged 3D microlens array, which has 341 plano-convex micro lenslets, on a thin spherical PMMA substrate. Using the fabricated 3D microlens array, a 3D micro projection system was developed. The formed micro pattern dimension was 340 um by 460 um, giving an overall projection ratio of 34:1. It has been demonstrated that a low cost and simple manufacturing process for true 3D micro scale structures on non-planar substrates based on microlenses can be realized. Last but not least, an affordable polymer SAR micromixer was developed based on a high accuracy, low cost, and flexible micro machining process. Specifically both the mixing performance and the fabrication process were carefully studied. An improved design of the SAR micromixer was also given, the mixing efficiency of the two designs were 0.11 and 0.065 respectively.

Diamond Turn Machining

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Author : R. Balasubramaniam
language : en
Publisher: CRC Press
Release Date : 2017-09-01

Diamond Turn Machining written by R. Balasubramaniam and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-09-01 with Technology & Engineering categories.

The goal of this book is to familiarize professionals, researchers, and students with the basics of the Diamond Turn Machining Technology and the various issues involved. The book provides a comprehensive knowledge about various aspects of the technology including the background, components of the machine, mechanism of material removal, application areas, relevant metrology, and advances taking place in this domain. Solved and unsolved examples are provided in each of the areas which will help the readers to practice and get familiarized with that particular area of the Diamond Turn Machining process.

An Empirical Survey On The Influence Of Machining Parameters On Tool Wear In Diamond Turning Of Large Single Crystal Silicon Optics

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Author :
language : en
Publisher:
Release Date : 1999

An Empirical Survey On The Influence Of Machining Parameters On Tool Wear In Diamond Turning Of Large Single Crystal Silicon Optics written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with categories.

The research described in this paper is a continuation of the collaborative efforts by Lawrence Livermore National Laboratory (LLNL), Schafer Corporation and TRW to develop a process for single point diamond turning (SPDT) of large single crystal silicon (SCSi) optical substrates on the Large Optic Diamond Turning Machine (LODTM). The principal challenge to obtaining long track lengths in SCSi has been to identify a set of machining parameters which yield a process that provides both low and predictable tool wear. Identifying such a process for SCSi has proven to be a formidable task because multiple crystallographic orientations with a range of hardness values are encountered when machining conical and annular optical substrates. The LODTM cutting program can compensate for tool wear if it is predictable. However, if the tool wear is not predictable then the figured area of the optical substrate may have unacceptably high error that can not be removed by post-polishing. The emphasis of this survey was limited to elucidating the influence of cutting parameters on the tool wear. We present two preliminary models that can be used to predict tool wear over the parameter space investigated. During the past two and one-half years a series of three evolutionary investigations were performed. The first investigation, the Parameter Assessment Study (PAS), was designed to survey fundamental machining parameters and assess their influence on tool wear [1]. The results of the PAS were used as a point-of-departure for designing the second investigation, the Parameter Selection Study (PSS). The goal of the PSS was to explore the trends identified in the PAS in more detail, to determine if the experimental results obtained in the PAS could be repeated on a different diamond turning machine (DTM), and to select a more optimal set of machining parameters that could be used in subsequent investigations such as the Fluid Down-Select Study (FDS). The goal of the FDS was to compare the performance of water, polyalkaline glycol and HT200 as a cutting fluid for SCSi, and select a single baseline cutting fluid from this set for use in future SCSi SPDT efforts. Synopses of the experimental work and results of the PAS and PSS are now presented.

Ductile Regime Turning Of Germanium And Silicon

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Author : National Aeronautics and Space Administration (NASA)
language : en
Publisher: Createspace Independent Publishing Platform
Release Date : 2018-08-17

Ductile Regime Turning Of Germanium And Silicon written by National Aeronautics and Space Administration (NASA) and has been published by Createspace Independent Publishing Platform this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-08-17 with categories.

Single-point diamond turning of silicon and germanium was investigated in order to clarify the role of cutting depth in coaxing a ductile chip formation in normally brittle substances. Experiments based on the rapid withdrawal of the tool from the workpiece have shown that microfracture damage is a function of the effective depth of cut (as opposed to the nominal cutting depth). In essence, damage created by the leading edge of the tool is removed several revolutions later by lower sections of the tool edge, where the effective cutting depth is less. It appears that a truly ductile cutting response can be achieved only when the effective cutting depth, or critical chip thickness, is less than about 20 nm. Factors such as tool rake angle are significant in that they will affect the actual value of the critical chip thickness for transition from brittle to ductile response. It is concluded that the critical chip thickness is an excellent parameter for measuring the effects of machining conditions on the ductility of the cut and for designing tool-workpiece geometry in both turning and grinding. Blake, Peter N. and Scattergood, Ronald O. Goddard Space Flight Center NASA-TM-101231, NAS 1.15:101231 ...

Low Cost Manufacturing Technologies

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Author : Shrikrishna Nandkishor Joshi
language : en
Publisher: Springer Nature
Release Date : 2023-03-15

Low Cost Manufacturing Technologies written by Shrikrishna Nandkishor Joshi and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-03-15 with Technology & Engineering categories.

This book is on various advanced, simple, and novel techniques being used and developed in the area of manufacturing processes. Manufacturing sector is one of the important areas which help to improve the economy of our nation. It not only generates employment opportunities but also makes us self-reliant (aatma nirbhar). In line with this important agenda of Government of India, this track envisages high-quality research contributions in the field of low-cost manufacturing technologies. It comprises the research and development studies on the various factors that influence the cost of manufacturing of product or system. The factors are materials, manufacturing processes, material handling processes, skilled manpower, quality control technologies, effective communication, and use of artificial intelligence techniques. The papers are on both numerical and experimental research works related to these aspects.

Examination Of Single Point Diamond Turning Tool Forces For Steady State Cutting Process Modeling

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Author : Dan Echizenya
language : en
Publisher:
Release Date : 2000

Examination Of Single Point Diamond Turning Tool Forces For Steady State Cutting Process Modeling written by Dan Echizenya and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with categories.