G. Vosniakos

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George-Christopher Vosniakos is Professor in Manufacturing Systems at the School of Mechanical Engineering, National Technical University of Athens (NTUA), Greece. He holds a first degree in Mechanical Engineering from NTUA (1986), an MSc in Advanced Manufacturing Technology (1987) from University of Manchester (formerly: UMIST). UK and a PhD in Intelligent CAD/CAPP Interfaces (1991) from UMIST, too. In the 1990s he worked in the ΙΤ industry in Germany and held a lecturer's post at UMIST. He has authored 83 journal articles, 78 conference papers, 5 book chapters and 80 technical reports in the fields of Advanced Manufacturing Technology and Intelligent Manufacturing Systems. He is member of the editorial board of Int. J. Advanced Manufacturing Technology, Int. J. of Machining and Machinability of Materials, Int. J. of Mechatronics and Manufacturing Systems and Advances in Robotics Research

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Residual Stress Distribution and Structural Phenomena of High-Strength Steel Surfaces Due to EDM and Ball-Drop Forming

CIRP Annals - Manufacturing Technology, 1988

... 270 m J *-.- We= 180mJ W,a 78 m J -..- 0 -..- Motrrlol : Mlcroolloyrd Depth below rurtacc, -v... more

Construction of a virtual reality environment for robotic manufacturing cells

International Journal of Computer Applications in Technology, 2015

Rough-cut fast numerical investigation of temperature fields in selective laser sintering/melting

The International Journal of Advanced Manufacturing Technology, 2016

Integrating Design and Production of Precision Traditional Ceramics

This paper advocates using state-of-the-art engineering tools in design and produc- tion of ceram... more This paper advocates using state-of-the-art engineering tools in design and produc- tion of ceramic parts and the corresponding pressing and casting dies. A feature li- brary is developed for the parametric design of parts with simple geometry, focusing on concave pottery parts. A user-friendly interface is developed, so that parametric design can be achieved by technicians with no proficiency in

Automatic Feature Extraction in Wire-Frame Models of 2 1/2-D Prismatic Parts

Proceedings of the Twenty-eighth International, 1990

A holistic approach to the exploitation of simulation in solid investment casting

by G. Vosniakos and D. Pantelis

Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2007

ABSTRACT The ultimate aim of casting simulation is to recommend process parameter values that res... more ABSTRACT The ultimate aim of casting simulation is to recommend process parameter values that result in the best possible casting quality. However, commercial casting simulation is currently used as a trial-and-error tool, mostly comparing between possible scenarios with no guarantee of realism. Three techniques are presented to overcome these discrepancies for solid investment casting of jewellery as a test bed. The first technique consists in recording temperature versus time profiles by thermocouples embedded in the casting. These profiles are used as calibration reference regarding the overall heat transfer coefficient at the melt-mould interface in simulation. The second technique consists in metallographic validation of simulation findings in terms of correlating microstructure and defects of the casting with simulation results concerning temperature distribution and porosity. The third technique consists in introducing genetic algorithms as an optimization tool. A small number of simulation sample runs link process parameters of interest, such as mould temperature and melt temperature, with results characterizing casting quality, e.g. porosity. These samples are used to train a neural network, thereby creating a generalized meta-model of the process, which is directly used as the fitness function of the genetic algorithm. Combining the three techniques described above caters for realistic and practical casting process planning using commercially available casting simulation software as a tool.

An intelligent software system for the automatic generation of NC programs from wireframe models of 2-1/2D mechanical parts

Computer Integrated Manufacturing Systems, 1998

On reference modelling of integrated manufacturing systems using OOA

Information Infrastructure Systems for Manufacturing, 1997

This work advocates the use of Object Orientation as basis of a methodology for creating referenc... more This work advocates the use of Object Orientation as basis of a methodology for creating reference models of manufacturing systems. Work on reference modelling of manufacturing systems integration is reviewed first. Then this work's own standpoint on reference modelling is outlined with definition of the main concepts. Reference models are distinguished from actual-implementation models through the need for generalisation, abstraction and expansion ability. Coad and Yourdon's Object Oriented Analysis is used to demonstrate reference modelling of structural, transformation and procedural aspects of a batchprocessing shop-floor system, explaining how manufacturing systems entities are mapped to OOA entities. The main concepts introduced along with discussion of relevant examples are a phenomenological View, application-related Views, abstraction hierarchy of objects and expansion ability of the model to advance from abstract to environment-specific reference models. Modular instancing of entities is also discussed in the context of further work.

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Flexible Integration of Shape and Functional Modelling of Machine Tool Spindles in a Design/Optimisation Framework

Materials Forming, Machining and Tribology, 2014

A software system framework for planning and operation of quality control in discrete part manufacturing

Computer Integrated Manufacturing Systems, 1997

... At the basic level further detail is given, mainly with regard to element connection. ... add... more

Intelligent Optimisation of 3-Axis Sculptured Surface Machining on Existing CAM Systems

Machining of Complex Sculptured Surfaces, 2012

A Web-Based Integrated Cutting Tool Management System

by G. Vosniakos and A. Daskalopoulos

Volume 3, 2004

ABSTRACT

Intelligence in Computer-Aided Process Planning for Machining

Advanced Manufacturing, 1999

CNC part program simulation using solid modelling techniques

by D. Kollios and G. Vosniakos

Intelligent systems for evaluation of gravity casting quality

Macroscopic and microscopic phenomena of electro-discharge machined steel surfaces: An experimental investigation

Journal of Mechanical Working Technology, 1987

Electro-discharge machining is a thermal process with a complex metal removal mechanism, involvin... more Electro-discharge machining is a thermal process with a complex metal removal mechanism, involving the formation of a plasma channel between the tool and workpiece electrodes, melting and evaporation action and shock waves, resulting in phase changes, tensile residual stresses, cracking and metallurgical transformation. These properties determine the operational behaviour of machined parts and are included in the term "surface integrity". Experimental results pertaining to the physico-chemical changes occurring during electro-discharge machining of steel (structural, medium-carbon and alloyed steels) surfaces are reported in this paper. Surface morphology and finish are assessed and correlated with overall process parameters and metal removal rates. Metallurgical transformations and new structures, surface damage in the form of cracking and "white layer" formation, microhardness variations and residual stress patterns are quantitatively and qualitatively examined and discussed. The results confirm the inherent complexity of the process, as well as the assumptions that must be made in order to achieve acceptable predictions of the mechanical and physico-chemical characteristics of the machined surfaces.

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Rapid evaluation of temperature distribution of coatings during atmospheric plasma sprayed process

by G. Vosniakos and D. Pantelis

International Journal of Surface Science and Engineering, 2015

Investigation of Centrifugal Casting Conditions Influence on Part Quality

by D. Pantelis and G. Vosniakos

Centrifugal casting is widely used as an investment casting method for small parts of complex geo... more Centrifugal casting is widely used as an investment casting method for small parts of complex geometry. Considering that the selection of casting conditions is not a trivial process, casting simulation programs could contribute to the enhancement of the process knowledge. In order to obtain realistic results from simulation, the input pa- rameters should be correctly defined. Determination of the interfacial

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Prediction of surface roughness in CNC face milling using neural networks and Taguchi's design of experiments

Robotics and Computer-Integrated Manufacturing, 2002

In this paper, a neural network modeling approach is presented for the prediction of surface roug... more In this paper, a neural network modeling approach is presented for the prediction of surface roughness (Ra) in CNC face milling. The data used for the training and checking of the networks' performance derived from experiments conducted on a CNC milling machine according to the principles of Taguchi Design of Experiments (DoE) method. The factors considered in the experiment were the depth of cut, the feed rate per tooth, the cutting speed, the engagement and wear of the cutting tool, the use of cutting fluid and the three components of the cutting force. Using feedforward artificial neural networks (ANNs) trained with the Levenberg -Marquardt algorithm, the most influential of the factors were determined, again using DoE principles, and a 5×3×1 ANN based on them, was able to predict the surface roughness with a mean squared error (MSE) equal to 1.86% and to be consistent throughout the entire range of values.

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Multiple tool path planning for NC machining of convex pockets without islands

Robotics and Computer-Integrated Manufacturing, 2000

This work focuses on machining of pockets with convex angles and containing no islands. The appro... more This work focuses on machining of pockets with convex angles and containing no islands. The approach is a hybrid contouring } staircasing one. Contouring aims at clearing enough space around the boundary to allow e$cient staircasing in the interior. Three tools are foreseen: two for contouring and one for staircasing. The algorithm for contouring is based on creating o!sets of the pocket boundary and checking them for self-crossing. Staircasing is based on parametrisation of the tool path with respect to its orientation to the pocket, so as to minimise the tool path length. Machining strategy is complemented by choosing the best combination of diameters of the three tools used. This is simply done by "rst enumerating all available combinations and then excluding the non-feasible ones, in order to compare the rest according to tool path length (or to machining time when individual feed values are known). The output of the program, which was implemented in Fortran, is the tool path, the CNC part program, which is created automatically, and a numerical comparison of all the tool-angle combinations tried out. A machining simulation based on the CNC program output is conducted on commercial CAM software to demonstrate validity of the result.

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