Sheet Metal Forming Processes And Die Design

Ebook Seller:www.ebookiran.ir Tel: 021-77495324 SHEET METAL FORMING PROCESSES AND DIE DESIGN VUKOTA BOLJANOVIC, Ph.D. Doctor in Technical Science Industrial Press New York Library of Congress Cataloging-in-Publication Data Boljanovic, Vukota. Sheet metal forming processes and die design / Vukota Boljanovic. p. cm. Includes bibliographical references and index. ISBN 0-83 11-3182-9 1 . Sheet-metal work. 2. Dies (Metal-working) I. Title. TS250.B8 15 2004 671.8’234~22 2004042151 Industrial Press Inc. 200 Madison Avenue New York, New York 10016 Copyright 02004. Printed in the United States of America. All rights reserved. This book or parts thereof may not be reproduced, stored in a retrieval system or transmitted in any form without the permission of the publisher. 10 9 8 7 6 5 4 3 2 DEDICATION To my children Vanju and Sashu, and to my wife, Anka TABLE OF CONTENTS xiii Preface xv List of Tables Introduction Basic Characteristics of Sheet-Metal Forming Processes Categories of Sheet-Metal Forming Processes Characteristics of Sheet-Metal Parts and Their Technological Properties PART I THEORETICAL FUNDAMENTALS The Structure of Metals Chapter 1 1.1 Introduction The Crystal Structure of Metals 1.2 Deformation and the Strength of Crystals 1.3 1.3.1 Imperfections in the Crystal Structure of Metals 1.3.2 Grain Sizes and Boundaries 1.3.3 Strain Hardening Recovery and Recrystalization 1.4 Chapter 2 2.1 2.2 2.3 2.4 Mechanical Behavior of Materials Introduction Stress / Strain Curves Ductility True Stress and True Strain xvii xvii xvii xviii 1 3 3 3 6 7 9 10 11 13 13 16 18 19 PART ZI MANUFACTURING PROCESSES Shearing Process Chapter 3 Mechanics of Shearing 3.1 Shearing Forces 3.2 3.2.1 Shearing with Straight Parallel Cutters 3.2.2 Shearing with Straight Inclined Cutters 3.3.3 Shearing with Rotary Cutters 21 23 23 23 24 25 27 Blanking and Punching Blanking and Punching Mechanism Blanking and Punching Clearances Punch Force Punch and Die with Parallel Cut Edges 29 29 31 33 33 Chapter 4 4.1 4.2 4.3 4.3.1 vii Table of Contents viii 'I 4.3.2 4.4 4.4.1 4.4.2 4.4.3 4.4.4 4.5 4.5.1 4.5.2 Chapter 5 5.1 5.2 5.3 5.3.1 5.3.2 5.4 5.4.1 5.4.2 5.4.3 5.4.4 5.4.5 5.5 5.5.1 5.5.2 5.6 5.7 5.8 Chapter 6 6.1 6.2 6.2.1 6.3 6.3.1 6.3.2 6.4 6.5 6.5.1 6.5.2 6.6 Punch and Die with Bevel-cut Edges Material Economy Scrap Strip Layouts Altering the Design of the Workpiece Multi-line Layout Utilizing Scrap from One Piece as Material for Another Piece Shaving Shaving a Punched Workpiece Shaving a Blanked Workpiece 34 35 35 37 37 38 39 39 43 Bending Introduction Mechanics of Bending Moment of Bending Moment of Bending in Elastic-Plastic Domain The Moment of Bending in the Purely Plastic Domain Bending Forces Force for a U-die Forces for a Wiping Die Forces for a V-die Curling Three-Roll Forming Bend Radius Minimum Bend Radius Maximum Bend Radius Bend Allowance Springback Clearance 45 45 45 46 49 50 Deep Drawing Introduction Mechanics of Deep Drawing Deep Drawability Forces First Drawing Operation Subsequent Drawing Operations Blank Calculations for Symmetrical Shells Determining Shape of Blank for Nonsymmetrical Shells Rectangular Shells Square Shells Drawing Practice 69 69 70 72 74 74 75 76 78 78 81 82 51 51 52 53 55 56 57 57 59 60 64 67 Table of Contents Defects During Deep Drawing Lubrication in Drawing 82 82 Various Forming Processes Stretch Forming Nosing Expanding Dimpling Spinning Flexible Die Forming Force in Die Forming 85 85 87 92 94 96 99 99 PART 111 DIE DESIGN Basic Die Classifications and Components Chapter 8 Die Classifications 8.1 Basic Die Components 8.2