Mechanical Engineering

Professor I. lnasaki (1) and Professor S. Malkin The application of A1 technologies using modem computers and controllers is seen as a way forward to produce higher quality components more efficiently with smaller batch sizes and more frequent changeovers. Users continue to demand better accuracy, surface integrity, and shorter cycle times with reduced operator intervention and increased flexibility. This paper reviews research into the use of AI methods to harness the knowledge and skills required to plan, set-up, operate and control grinding processes. Basic A1 concepts are introduced and discussed particularly in the context of application to grinding. Two main trends are evidenced in the development of AI technologies in grinding: desktop systems to assist tool and parameter selection and self-optimising systems integrated within the machine controller. It is predicted that future developments will favour increasing communication between these two levels of control within a CIM environment. The development of modular systems which are sufficiently robust to plan, supervise and control abrasive processes requires ongoing research and development.

Design data are presented for the static performance of gas-fed cylindrical journal bearings employing slot restrictors. The calculations are based on the accurate finite difference technique and reveal the safe limits of loading. Results are given for both single-row and double-row configurations.

Bearing design procedures have improved considerably during the past decade. Originally most designers used the simplified procedures and empirical rules then available, reinforced with practical experience. With the progressive development of rotating machinery, bearings were subjected to increasingly arduous conditions. The existing procedures proved unsatisfactory at predicting the real margin of safety under these circumstances, with the consequent risk of over-design or premature bearing damage.

Over the last century, substantial advances have been made, based on improved understanding of the requirements of grinding processes, machines, control systems, materials, abrasives, wheel preparation, coolants, lubricants, and coolant delivery. This paper reviews a selection of areas in which the application of scientific principles and engineering ingenuity has led to the development of new grinding processes, abrasives, tools, machines, and systems. Topics feature a selection of areas where relationships between scientific principles and new techniques are yielding improved productivity and better quality. These examples point towards further advances that can fruitfully be pursued. Applications in modern grinding technology range from high-precision kinematics for grinding very large lenses and reflectors through to medium size grinding machine processes and further down to grinding very small components used in micro electro-mechanical systems (MEMS) devices. The importance of material issues is emphasized for the range of conventional engineering steels, through to aerospace materials, ceramics, and composites. It is suggested that future advances in productivity will include the wider application of artificial intelligence and robotics to improve precision, process efficiency, and features required to integrate grinding processes into wider manufacturing systems.

The application of '41 technologies using modem computers and controllers is seen as a way forward to produce higher quality components more efficiently with smaller batch sizes and more frequent changeovers. Users continue to demand better accuracy, surface integrity, and shorter cycle times with reduced operator intervention and increased flexibility. This paper reviews research into the use of intelligent control and optimisation techniques in grinding and propose the incorporation of intelligent techniques into computer numerical controls (CNCs). Two main trends are evidenced in the development of AI technologies in grinding: desktop systems to assist tool and parameter selection and self-optimising systems integrated within the machine controller. It is predicted that future developments will favour increasing incorporation of intelligence into CNC. The development of modular systems which are sufficiently robust to plan. supervise and control abrasive processes requires ongoing research and development.

Recent and radically improved machining processes, from high wheel speeds to nanotechnology, have turned a spotlight on abrasive machining processes as a fertile area for further advancements. Written for researchers, students, engineers and technicians in ...

AMTReL, General Engineering Research Institute, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK E-mail: [email protected] E-mail: [email protected] *Corresponding author ... Balance Systems srl, Italy E-mail: [email protected]

The application of '41 technologies using modem computers and controllers is seen as a way forward to produce higher quality components more efficiently with smaller batch sizes and more frequent changeovers. Users continue to demand better accuracy, surface integrity, and shorter cycle times with reduced operator intervention and increased flexibility. This paper reviews research into the use of intelligent control and optimisation techniques in grinding and propose the incorporation of intelligent techniques into computer numerical controls (CNCs). Two main trends are evidenced in the development of AI technologies in grinding: desktop systems to assist tool and parameter selection and self-optimising systems integrated within the machine controller. It is predicted that future developments will favour increasing incorporation of intelligence into CNC. The development of modular systems which are sufficiently robust to plan. supervise and control abrasive processes requires ongoing research and development.

This paper describes an experimental and analytical study of the effect of centrifugal and clamping forces on stress distributions in vitreous-bonded cylindrical grinding wheels. The stress distributions are found to be a function of the magnitude of the clamping force and the distribution of the clamping force across the flange/wheel interface, the frictional forces, wheel speed, and the ratio of compressive to tensile strength of the wheel material. The safe limits of the clamping force are presented which fultil the requirements of the flange assembly during the burst test. The implications of the present study for safe grinding practice are discussed.

In modern competitive manufacturing industry, machining processes are expected to deliver products with high accuracy and assured surface integrity, using shorter cycle times with reduced operator intervention and increased flexibility. To meet such demands, the trend towards increased use of machine intelligence in machining systems and operations is clear and unlikely to be revised. This paper describes the structure, content and relations employed in a fully integrated intelligent grinding system for adaptive controlled cycle optimisation, thermal damage avoidance, dressing interval optimisation and data retention. This system, termed: 'Intelligent Grinding Assistant' (IGA©) is a unique, robust and versatile software system with embedded links and protocols for communication with the Computer Numerical Control (CNC) and instrumentation of a grinding machine. The IGA© was evaluated and implemented on a commercially available production machine and had its international launch in September 2005. The CNC, machine tool instrumentation, process monitoring and data analysis systems, Profibus link, and control strategies all constituted the IGA© system. Grinding performance was monitored and assessed in real time. An intelligent database was also developed to support the IGA© in the provision of optimised and/or safe starting cycle data to the operator/adaptive system and in the selective

The aim of the investigation was to achieve a method of assessment of vitrified CBN wheels for precision grinding based on investigation of relationships between the changing features of grinding wheels and grinding performance. Feasible measurement and observation techniques for the changing topographical features of vitrified CBN wheels in grinding were investigated. Comparisons included measurement resolution, measuring depth, ease of application, and data analysis and interpretation. The optical interferometer was found to be good for I would like to express my sincere gratitude to Professor W. Brian Rowe, my Director of Studies, for his invaluable guidance and encouragement throughout the research and his creative suggestions in preparing this thesis. Thanks are expressed to my second supervisor, Dr. X. Chen, for his assistance in my initial work. Thanks are also due to my third supervisor Professor Ben Mills, particular for his support in providing information concerning new products and suggestions for the experimental system. I would like to thank Mr. Stephen Ebbrell who cooperated in the EPSRC supported project, for his help and cooperation thoughout my study. I would also like to thank Dr. Michael Morgan for his suggestions for this thesis. Thanks are due to Mr. Paul Wright and Mr. Peter Moran for technical support and advice in organizing the experimental facilities, Mr. Thomas Scargill, for his hard work and patience throughout the whole series of experiments, Mr. Michael Noord for his practical help in many aspects.

This paper describes an experimental and analytical study of the effect of centrifugal and clamping forces on stress distributions in vitreous-bonded cylindrical grinding wheels. The stress distributions are found to be a function of the magnitude of the clamping force and the distribution of the clamping force across the flange/wheel interface, the frictional forces, wheel speed, and the ratio of compressive to tensile strength of the wheel material. The safe limits of the clamping force are presented which fultil the requirements of the flange assembly during the burst test. The implications of the present study for safe grinding practice are discussed.

The paper systematically reviews experimental research on the performance of cubic boron nitride (CBN) grinding wheels and discusses advantages and difficulties experienced in the application of CBN wheels particularly for internal grinding with finegrain wheels. The hardness of CBN grains potentially increases redress life and improves dimensional stability. The problem is that increased redress life increases the importance of avoiding wheel loading, particularly for small-grain wheels. This paper highlights the importance of touch dressing for improved dimensional stability and other operational techniques to maintain an open surface topography of the wheel. The paper also demonstrates the benefit of an open-structured small-grain CBN wheel for precision grinding. Effects on grinding temperature are also illustrated.