Principles of Modern Grinding Technology Principles of Modern Grinding Technology Second Edition W. Brian Rowe AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO William Andrew is an imprint of Elsevier William Andrew is an imprint of Elsevier 225 Wyman Street, Waltham, MA 02451, USA The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK First edition 2009 Second edition 2014 Copyright © 2014 Elsevier Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: (144) 1865 843830, fax: (144) 1865 853333, e-mail: permissions@elsevier.
You may also complete your request by visit- ing the Elsevier website at http://elsevier.com/locate/permissions, and selecting Obtaining permission to use Elsevier material Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress. British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. ISBN: 978-0-323-24271-4 For information on all William Andrew publications visit our website at http://store.com/ Printed in the United States of America 14 15 16 17 18 10 9 8 7 6 5 4 3 2 1 Dedication I dedicate this book to my wife Margaret Ruth for her love and support throughout my work, the mother of my children Ivor and Ella and my constant companion. Preface Principles of Modern Grinding Technology explains in simple terms the principles that led to rapid improvements in modern grinding technology over recent decades.
Removal rates and quality standards have increased a hundred-fold. Very fine toler- ances are routine due to improved understanding of the process and the factors that need to be controlled. Superb grinding machines now produce optical-quality finishes due to develop- ments in process control and machine design. It is the same for extremely high removal rates.
This book shows how best quality can be improved and costs can be brought down at the same time as output is increased. The book is aimed at practitioners, engineers, researchers, students and teachers. The approach is direct, concise and authoritative. This edition introduces additional materials including data, photographs, updated references and design examples.
There are additions in most chapters including abrasives, dressing, cooling, high- speed grinding, centreless grinding, materials, wear, temperatures and heat transfer. There are numerous worked examples. Progressing through each major element of a grinding system and then on to machine developments, the reader becomes aware of all aspects of operation and design. Trends are described demonstrating key fea- tures.
Coverage includes abrasives and superabrasives, wheel design, dressing tech- nology, machine accuracy and productivity, machine design, high-speed grinding technology, cost optimization, ultra-precision grinding, process control, vibration control, coolants and fluid delivery, thermal damage and grinding temperatures. Advances in the field are supported with references to leading research. Analysis is presented in later chapters and appendices with new contributions to machine design, intelligent control, centreless grinding, fluid delivery, cost analysis and thermal analysis for prediction and control of grinding temperatures are pro- vided. By selecting the right conditions, extremely high removal rates can be achieved accompanied by low temperatures.
Techniques for measurement of grind- ing temperatures are also included. This edition includes recent process developments and additional design examples. G Trends in high precision and high-speed grinding are explored. G Principles underlying improvements in machines and processes are explained.
G Numerical worked examples give scale to essential process parameters. G Recent research findings and original contributions to knowledge are included. G A number of ultra-precision grinding machine developments are included. Acknowledgements I wish to record sincere gratitude for the help and friendship provided by research students, research fellows, colleagues and visiting scholars with whom I had the privilege to work and whose valuable contributions made this volume possible.
A number of these have achieved well-deserved distinction in academic and industrial spheres. The list, roughly in date order, includes D. Baines-Jones and Zhang Lei. I would especially like to mention Paul Wright who, through his invaluable contributions, helped me and many researchers succeed in their projects.
Eventually he became manager of the labora- tories within the School of Engineering at Liverpool John Moores University. Brian Rowe About the Author W. Brian Rowe is a research and consulting engineer, Emeritus Professor and pre- vious Director of Advanced Manufacturing Technology and Tribology Research Laboratory (AMTTREL) at Liverpool John Moores University in the United Kingdom. A multiple recipient of prizes from The Institution of Mechanical Engineers (IMECHE), Dr Rowe has four decades of experience in academic and industrial positions concerned with machine tools, grinding processes and tribol- ogy.
His accomplishments include over 250 published papers, several books, international visiting professorships and international consulting in industry. List of Abbreviations ACO Adaptive control optimization AE Acoustic emission ANSI American National Standards Institution BN Barkhausen Noise CBN Cubic boron nitride CIRP International Academy of Production Engineering Research CNC Computer numerical control CVD Chemical vapour deposited CW Control wheel ED Electrical discharge EDD Electrical discharge dressing ELID Electrolytic in-process dressing EP Electroplated FEPA Federation of European Producers of Abrasives FWM Fluid wheel model of fluid convection GW Grinding wheel HEDG High-efficiency deep grinding HEG High-efficiency grinding HSS High speed steel ID Impregnated diamond ISO International Standards Organization JIS Japanese Industrial Standards LFM Laminar flow model of fluid convection MQL Minimum quantity lubrication MRR Material removal rate PCD Poly-crystalline diamond PLCs Programmable logic controls PVD Physical vapour deposition RMS Root mean square SD Single-point diamond SEM Scanning electron microscope SG Seeded gel (alumina composite abrasive) trade name SI ISO international system (e. units) SiC Silicon carbide UFM Useful flow model VHN Vickers Hardness Number WP Workpiece Notation for Grinding Parameters Note: Symbols within a special context are explained in the relevant text. a Depth of cut or hydrostatic bearing land width ad Dressing depth of cut ae Effective (real) depth of cut in grinding ap Programmed (set) depth of cut in grinding b, br, bw Width of grinding wheel contact with work bcu Width of uncut chip bd Dressing tool contact width br Radial width of cut c Machine damping c, cp Specific heat capacity cd, cv, ca Discharge, velocity and area coefficients in nozzle flow d Diameter in pipe flow dc Control wheel diameter in centreless grinding de Effective grinding wheel diameter dg Mean abrasive grain diameter ds Actual grinding wheel diameter dw Workpiece diameter e Error ec,u Specific grinding energy (energy per unit volume removed) ech Specific energy carried in chips erf( ) Error function given in math tables f Frequency in cycles per second (Hz) f Interface friction factor 5 τ/k f Grain force h Thin film or chip thickness h, hf Convection factor and work-fluid convection factor hcu Uncut chip thickness heq Equivalent chip thickness hg Convection factor into a grain hw Work height in centreless grinding hwg Convection factor into the workpiece at a grain contact j Complex number operator k Shear flow stress k Thermal conductivity kw, kg Thermal conductivity of work material and abrasive grain lc Contact length lf Contact length due to force and deflection of grinding wheel and workpiece lg Geometric contact length due to depth of cut xxxiv Notation for Grinding Parameters n Number of grinding passes n Junction growth factor nd Number of dressing passes ns Grinding wheel rotational speed nw Work rotational speed p Instantaneous power pp Fluid pumping pressure q Speed ratio 5 vs/vw q Flux value 5 heat per unit area in unit time qd Dressing roll speed ratio 5 vd/vs qflash Flux into the workpiece at a flash contact rcu Uncut chip width/chip thickness ratio 5 bcu/hcu ro Average effective grain contact radius s Laplace operator in vibration theory t Time td Dressing time tp Point/flash contact time of grain and workpiece ts Grinding cycle time ts Grain contact time within contact length tt Total cycle time including grinding and dressing ui Input to a control system uo Output from a control system v Mean velocity in pipe flow vd Dressing roll speed vf Work feed rate vfd Dressing feed rate vj Jet velocity vs Wheel speed vw Work speed x Deflection x, y, z Position coordinates A Geometric stability parameter in centreless grinding A Wear flat area on grinding wheel as fraction or percentage Ac Apparent area of grinding contact zone 5 lc b G Acu Cross-section area of uncut chip Al2O3 Aluminium oxide, alumina B Lateral grain spacing C Number of active abrasive grains per unit area 5 cutting edge density C C-factors giving temperature for particular grinding conditions Ct Total cost per part D Diameter as in journal diameter E Young modulus of elasticity Fa, F0 a Axial force and specific value per unit width Fn, F0 n Normal force and specific value per unit width Ft, F0 t Tangential force and specific value per unit width G G-ratio H Feedback function in a control system Ha Depth of cut function in vibrations Notation for Grinding Parameters xxxv Hf Fluid drag power Hp Fluid pumping power Hs Wheel wear function in vibrations Ht Total fluid power K Grinding stiffness factor 5 ae/ap K Power ratio 5 Hf/Hp K Archard wear constant Ks Grinding stiffness 5 Fn/ae K1 Work-plate factor in centreless grinding K2 Control wheel factor in centreless grinding L, B Grain spacing in grinding direction and in lateral direction L Length as in bearing length or work length L Peclet number related to thermal diffusivity Nd Number of parts per dress P, P0 Grinding power and power per unit width PNL No-load power Ps, Pp Supply pressure and pumped pressure Q Dynamic magnifier of machine deflection Q Bearing flow-rate Q, Qw Removal rate, workpiece removal rate Q0 , Q0 w Removal rate per unit width Qf Nozzle fluid flow-rate Qu Useful fluid flow-rate Ra, Rt, Rz ISO surface roughness parameters Re Reynolds number RL Contact length ratio 5 lc/lg Rr Roughness factor 5 lfr/lfs Rw Fraction of heat going into workpiece Rws Work-wheel interface fraction of heat into workpiece Scu Surface area of the uncut chip SiC Silicon carbide SG Seeded gel (alumina composite abrasive) trade name T, ΔT Temperature or temperature rise Ud Dressing overlap ratio V Volume removed Vcu Chip volume removed α Thermal diffusivity 5 k/ρc α Work-plate-wheel contact pffiffiffiffiffiffiffiffiffiangle ffi in centreless grinding β Thermal property 5 k:ρ:c β Tangent contact angle in centreless grinding β Bearing pressure ratio 5 design value of recess pressure/supply pressure γ Work-plate angle in centreless grinding γ Friction angle 5 (cos-1f )/2 γd Dressing sharpness ratio 5 ad/bd ϕ Grinding contact angle 5 lc/de radians Φ Wheel porosity Φ Through-feed angle in centreless grinding ρ Density 5 mass per unit volume xxxvi Notation for Grinding Parameters σ Direct stress τ Time constant of an exponential decay or growth τ Shear stress λ Static grinding system stiffness λ(jω) Dynamic grinding system stiffness μ Grinding force ratio υ Poisson ratio ω Frequency (radians per second) ωn ωo Natural frequency, resonant frequency (radians per second) Ω Work angular speed (radians per second) Commonly Used Suffixes and Affixes Which Modify a General Symbol Depending on the Context in Which It Is Used a Axial or ambient c Contact or cutting ch Chip cu Uncut chip d Dressing or discharge e Effective f Fluid or force g Geometric or grain i Instantaneous or input j Jet max Maximum n Normal or natural o Datum or zero or natural or output p Pressure or pumping or programmed or ploughing r Radius or roughness s Wheel or supply or sliding t Tangential or total u Useful v velocity w Workpiece or width ws Workpiece-wheel L Length NL No-load Basic Units and Conversion Factors Length 1 metre 5 39.37 inches Mass 1 kilogram 5 2.205 pounds mass Force 1 newton 5 0.2248 pounds Energy 1 joule 5 0.