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Shiv Gopal Kapoor

Bio: Shiv Gopal Kapoor is an academic researcher from University of Illinois at Urbana–Champaign. The author has contributed to research in topics: Machining & Drill. The author has an hindex of 46, co-authored 275 publications receiving 8123 citations. Previous affiliations of Shiv Gopal Kapoor include Southwest Research Institute & University of Minnesota.


Papers
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Journal ArticleDOI
TL;DR: In this article, the authors provide a comprehensive review of the literature that is enhancing our understanding of the mechanics of the rapidly growing field of micromachining and discuss both experimental and modeling studies.
Abstract: This paper provides a comprehensive review of the literature, mostly of the last 10-15 years, that is enhancing our understanding of the mechanics of the rapidly growing field of micromachining. The paper focuses on the mechanics of the process, discussing both experimental and modeling studies, and includes some work that, while not directly focused on micromachining, provides important insights to the field. Experimental work includes the size effect and minimum chip thickness effect, elastic-plastic deformation, and microstructure effects in micromachining. Modeling studies include molecular dynamics methods, finite element methods, mechanistic modeling work, and the emerging field of multiscale modeling. Some comments on future needs and directions are also offered.

406 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined the surface generation process in the micro-endmilling of both single-phase and multiphase workpiece materials and developed a surface generation model to predict the surface roughness for the slot floor centerline.
Abstract: This paper examines the surface generation process in the micro-endmilling of both single-phase and multiphase workpiece materials. We used 508 μm dia endmills with edge radii of 2 and 5 μm to machine slots in ferrite, pearlite, and two ductile iron materials at feed rates ranging from 0.25 to 3.0 mm/flute. A surface generation model to predict the surface roughness for the slot floor centerline is then developed based on the minimum chip thickness concept. The minimum chip thickness values were found through finite element simulations for the ferrite and pearlite materials. The model is shown to accurately predict the surface roughness for single-phase materials, viz., ferrite and pearlite. Two phenomena were found to combine to generate an optimal feed rate for the surface generation of single-phase materials: (i) the geometric effect of the tool and process geometry and (ii) the minimum chip thickness effect. The surface roughness measurements for the ductile iron workpieces indicate that the micromilling surface generation process for multiphase workpiece materials is also affected by the interrupted chip-formation process as the cutting edge moves between phases resulting in burrs at the phase boundaries and the associated increases in surface roughness.

310 citations

Journal ArticleDOI
TL;DR: In this paper, a summary of work performed in the area of modeling the dynamic metal cutting process is presented, and a general view of evolution of the dynamic cutting process models is depicted.
Abstract: In this paper, a summary of work performed in the area of modeling of the dynamic metal cutting process is presented. A general view of evolution of the dynamic cutting process models is depicted. Specifically four modeling approaches including analytical, experimental, mechanistic and numerical methods are critically reviewed. A brief assessment offuture research needs is also given.

279 citations

Journal ArticleDOI
TL;DR: In this paper, an analytical model has been developed to predict the minimum chip thickness values, which are critical for the process model development and process planning and optimization, and the model accounts for the effects of thermal softening and strain hardening on the minimum chips thickness.
Abstract: In micromachining, the uncut chip thickness is comparable or even less than the tool edge radius and as a result a chip will not be generated if the uncut chip thickness is less than a critical value, viz., the minimum chip thickness. The minimum chip thickness effect significantly affects machining process performance in terms of cutting forces, tool wear, surface integrity, process stability, etc. In this paper, an analytical model has been developed to predict the minimum chip thickness values, which are critical for the process model development and process planning and optimization. The model accounts for the effects of thermal softening and strain hardening on the minimum chip thickness. The influence of cutting velocity and tool edge radius on the minimum chip thickness has been taken into account. The model has been experimentally validated with 1040 steel and A16082-T6 over a range of cutting velocities and tool edge radii. The developed model has then been applied to investigate the effects of cutting velocity and edge radius on the normalized minimum chip thickness for various carbon steels with different carbon contents and A16082-T6.

250 citations

Journal ArticleDOI
TL;DR: In this paper, a slip-line field is developed to model the ploughing components of the cutting force, based on other slip line fields developed for a rigid wedge sliding on a half space and for negative rake angle orthogonal cutting.
Abstract: Under normal machining conditions, the cutting forces are primarily due to the bulk shearing of the workpiece material in a narrow zone called the shear zone. However, under finishing conditions, when the uncut chip thickness is of the order of the cutting edge radiu a ploughing component of the forces becomes significant as compared to the shear forces. Predicting forces under these conditions requires an estimate of ploughing. A slip-line field is developed to model the ploughing components of the cutting force. The field is based on other slip-line fields developed for a rigid wedge sliding on a half-space and for negative rake angle orthogonal cutting. It incorporates the observed phenomena of a small stable build-up of material adhered to the edge and a raised prow of material formed ahead qf the edge, The model shows how ploughing forces are related to cutter edge radius - a larger edge causing larger ploughing forces, A series of experiments were run on 6061-T6 aluminum using tools with different edge radii-including some exaggerated in size-and different levels of uncut chip thickness. Resulting force measurements match well to predictions using the proposed slip-line field, The results show great promise for understanding and quantifying the effects of edge radius and worn tool on cutting forces.

242 citations


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Book
13 Apr 2000
TL;DR: In this paper, the authors discuss the application of metal cutting to manufacturing problems, including the design of real-time trajectory generation and interpolation algorithms, and CNC-oriented error analysis.
Abstract: Metal cutting is a widely used method of producing manufactured products. The technology of metal cutting has advanced considerably along with new materials, computers, and sensors. This new edition treats the scientific principles of metal cutting and their practical application to manufacturing problems. It begins with metal cutting mechanics, principles of vibration, and experimental modal analysis applied to solving shop floor problems. Notable is the in-depth coverage of chatter vibrations, a problem experienced daily by manufacturing engineers. The essential topics of programming, design, and automation of CNC (computer numerical control) machine tools, NC (numerical control) programming, and CAD/CAM technology are discussed. The text also covers the selection of drive actuators, feedback sensors, modeling and control of feed drives, the design of real time trajectory generation and interpolation algorithms, and CNC-oriented error analysis in detail. Each chapter includes examples drawn from industry, design projects, and homework problems. This book is ideal for advanced undergraduate and graduate students, as well as practicing engineers.

1,854 citations

Journal ArticleDOI
TL;DR: There are significant roots in general and in particular to the CIRP community – which point towards CPPS, and expectations towards research in and implementation of CPS and CPPS are outlined.
Abstract: One of the most significant advances in the development of computer science, information and communication technologies is represented by the cyber-physical systems (CPS). They are systems of collaborating computational entities which are in intensive connection with the surrounding physical world and its on-going processes, providing and using, at the same time, data-accessing and data-processing services available on the Internet. Cyber-physical production systems (CPPS), relying on the latest, and the foreseeable further developments of computer science, information and communication technologies on one hand, and of manufacturing science and technology, on the other, may lead to the 4th industrial revolution, frequently noted as Industrie 4.0. The paper underlines that there are significant roots in general – and in particular to the CIRP community – which point towards CPPS. Expectations towards research in and implementation of CPS and CPPS are outlined and some case studies are introduced. Related new R&D challenges are highlighted.

1,123 citations

Journal ArticleDOI
TL;DR: In this paper, the past contributions of CIRP in these areas are reviewed and an up-to-date comprehensive survey of sensor technologies, signal processing, and decision making strategies for process monitoring is provided.

1,074 citations

Journal ArticleDOI
TL;DR: This paper presents an overview of nanopositioning technologies and devices emphasizing the key role of advanced control techniques in improving precision, accuracy, and speed of operation of these systems.
Abstract: Nanotechnology is the science of understanding matter and the control of matter at dimensions of 100 nm or less. Encompassing nanoscale science, engineering, and technology, nanotechnology involves imaging, measuring, modeling, and manipulation of matter at this level of precision. An important aspect of research in nanotechnology involves precision control and manipulation of devices and materials at a nanoscale, i.e., nanopositioning. Nanopositioners are precision mechatronic systems designed to move objects over a small range with a resolution down to a fraction of an atomic diameter. The desired attributes of a nanopositioner are extremely high resolution, accuracy, stability, and fast response. The key to successful nanopositioning is accurate position sensing and feedback control of the motion. This paper presents an overview of nanopositioning technologies and devices emphasizing the key role of advanced control techniques in improving precision, accuracy, and speed of operation of these systems.

1,027 citations