Gebhardt Understanding Additive Manufacturing Andreas Gebhardt Understanding Additive Manufacturing Rapid Prototyping · Rapid Tooling · Rapid Manufacturing Hanser Publishers, Munich Hanser Publications, Cincinnati The Author: Prof. Dr.-Ing. Andreas Gebhardt CP-Center of Prototyping (Centrum für Prototypenbau GmbH) Strassburger Allee 13, 41812 Erkelenz, Germany Institute for Advanced Fabrication Technologies and Additive Manufacturing (Lehr- und Forschungsgebiet Hochleistungsverfahren der Fertigungstechnik und Additive Manufacturing), FH Aachen University of Applied Sciences, Goethestr. 1, 52064 Aachen, Germany Distributed in North and South America by: Hanser Publications 6915 Valley Avenue, Cincinnati, Ohio 45244-3029, USA Fax: (513) 527-8801 Phone: (513) 527-8977 www.hanserpublications.com Distributed in all other countries by Carl Hanser Verlag Postfach 86 04 20, 81631 München, Germany Fax: +49 (89) 98 48 09 www.hanser.de The use of general descriptive names, trademarks, etc., in this publication, even if the former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone. While the advice and information in this book are believed to be true and accurate at the date of going to press, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Library of Congress Cataloging-in-Publication Data Gebhardt, Andreas. Understanding additive manufacturing / Andreas Gebhardt. p. cm. ISBN-13: 978-1-56990-507-4 (hardcover) ISBN-10: 1-56990-507-X (hardcover) 1. Three-dimensional printing. 2. Manufacturing processes. I. Title. TS171.8.G43 2011 658.5--dc23 2011040743 Bibliografische Information Der Deutschen Bibliothek Die Deutsche Bibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet über <http://dnb.d-nb.de> abrufbar. ISBN 978-3-446-42552-1 E-Book-ISBN 978-3-446-43162-1 All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying or by any information storage and retrieval system, without permission in writing from the publisher. © Carl Hanser Verlag, Munich 2011 Production Management: Steffen Jörg Coverconcept: Marc Müller-Bremer, www.rebranding.de, München Coverdesign: Stephan Rönigk Typeset: Manuela Treindl, Fürth Printed and bound by Kösel, Krugzell Printed in Germany Acknowledgements The interdisciplinary character of additive manufacturing technology as well as the tremendous speed of its development make it almost impossible for an individual to present it completely, accurately, and topically. Therefore, I am very thankful for the help and support provided by friends, colleagues, and companies involved in the field. Special thanks go to my colleagues of the Center of Prototyping, Erkelenz, Germany, who provided the continuous contact to the “shop floor” that is the basis for the practical orientation of this book. Personal thanks go to Besima Sümer, Christoph Schwarz and Michael Wolf. The preparation of the background material was supported in conjunction with the EU TEMPUS Project “Development of Master’s Studies in Industrial Design and Marketing”, JEP-41128-2006 (MK). Thanks to my colleagues Tatjana Kandikjan and Sofija Sidorenko, Ss. Cyril and Methodius University, Faculty of Mechanical Engineer- ing, Skopje, Macedonia. Personal thanks to my chief editor, Dr. Christine Strohm, who provided help with orga- nizing my ideas in a well structured format and polishing my English language skills. Table of Contents 1 Basics, Definitions, and Application Levels ....................................................1 1.1 Basics and Definitions...............................................................................................................2 1.1.1 Additive Manufacturing – Layer Manufacturing .......................................................2 1.1.2 The Principle of Layer-Based Technology ....................................................................3 1.2 Application Levels .....................................................................................................................5 1.2.1 Direct Processes ..............................................................................................................7 1.2.1.1 Rapid Prototyping .............................................................................................7 1.2.1.2 Rapid Manufacturing.....................................................................................11 1.2.2.3 Rapid Tooling ..................................................................................................12 1.3 Application Levels – Indirect Processes .............................................................................17 1.3.1 Indirect Prototyping .....................................................................................................17 1.3.2 Indirect Tooling .............................................................................................................20 1.3.3 Indirect Manufacturing ...............................................................................................22 1.4 Classes of Machines for Additive Manufacturing .............................................................25 1.4.1 Fabricators and Others ................................................................................................25 1.4.2 Nomenclature of AM Machines ..................................................................................25 1.5 Conclusion ...............................................................................................................................27 1.6 Questions ..................................................................................................................................28 2 Layer Manufacturing Processes ....................................................................31 2.1 Direct Layer Manufacturing Processes ...............................................................................31 2.1.1 Polymerization ..............................................................................................................34 2.1.1.1 Laser-Stereolithography (SL) ........................................................................34 2.1.1.2 Polymer Printing and –Jetting .....................................................................37 2.1.1.3 Digital Light Processing ................................................................................38 2.1.1.4 Micro Stereolithography ...............................................................................39 2.1.2 Sintering and Melting ..................................................................................................40 2.1.2.1 Laser Sintering – Selective Laser Sintering (LS – SLS) ...........................40 2.1.2.2 Laser Melting – Selective Laser Melting (SLM) ........................................42 2.1.2.3 Electron Beam Melting ..................................................................................44 2.1.3 Extrusion – Fused Layer Modeling............................................................................45 VIII Table of Contents 2.1.4 Powder-Binder Bonding – Three Dimensional Printing (Drop on Powder Processes) .......................................................................................47 2.1.4.1 Three Dimensional Printing – Z-Corporation ............................................48 2.1.4.2 Three Dimensional Printing – Prometal ....................................................50 2.1.4.3 Three Dimensional Printing – Voxeljet ......................................................51 2.1.5 Layer Laminate Manufacturing (LLM) ......................................................................52 2.1.5.1 Layer Laminate Manufacturing, Laminated Object Manufacturing (LOM) ...............................................................................................................52 2.1.5.2 Layer Laminate Manufacturing, Paper Lamination, MCOR Matrix .......54 2.1.5.3 Layer Laminate Manufacturing, Plastic Laminate Printers ....................54 2.1.5.4 LLM Machines for Metal Parts .....................................................................55 2.1.6 Other Processes: Aerosolprinting and Bioplotter ....................................................56 2.1.6.1 Aerosolprinting ..............................................................................................56 2.1.6.2 Bioplotter .........................................................................................................56 2.2 Machines for Additive Manufacturing – Fabricators, Printers, and more ....................58 2.3 Secondary Rapid Prototyping Processes .............................................................................59 2.4 Conclusions and Perspective ................................................................................................61 2.5 Questions ..................................................................................................................................62 3 Applications .....................................................................................................65 3.1 Data Processing and Application Workflow .......................................................................66 3.1.1 AM Process Chain ........................................................................................................66 3.1.2 Application Workflow ..................................................................................................67 3.1.2.1 Workflow for Rapid Prototyping ..................................................................68 3.1.2.2 Workflow for Rapid Manufacturing ............................................................69 3.1.3 STL Data Structure, Errors, and Repair ....................................................................70 3.2 Applications of AM .................................................................................................................73 3.2.1 Automotive Industries and Suppliers .......................................................................73 3.2.1.1 Car Components: Interior .............................................................................73 3.2.1.2 Car Components: Exterior ............................................................................75 3.2.2 Aerospace Industry ......................................................................................................76 3.2.3 Consumer Goods ...........................................................................................................78 3.2.4 Toy Industry ..................................................................................................................82 3.2.5 Art and History of Art ..................................................................................................83 3.2.6 Foundry and Casting Technology ..............................................................................85 3.2.6.1 Sand Casting ...................................................................................................86 3.2.6.2 Investment Casting ........................................................................................88 3.2.7 Mold and Die Making for Plastic Injection Molding and Metal Die Casting ......89 3.2.8 Medical ...........................................................................................................................91 3.2.9 Architecture and Landscaping ...................................................................................93 3.10 Miscellaneous ..........................................................................................................................96 3.11 Conclusion ...............................................................................................................................98 3.12 Questions ..................................................................................................................................99 Table of Contents IX 4 Additive Manufacturing Design and Strategies .........................................103 4.1 About the Potential of AM ...................................................................................................103 4.2 Potentials and Resulting Perspectives...............................................................................104 4.2.1 Complex Geometries ..................................................................................................104 4.2.2 Integrated Geometry ..................................................................................................106 4.2.3 Integrated Functionalities .........................................................................................108 4.2.4 Multi-Material Parts and Graded Materials ...........................................................115 4.3 AM-Based New Strategies – Customization .....................................................................117 4.3.1 Customized Mass Production ...................................................................................118 4.3.1.1 One-Offs and Small Batch Production .......................................................118 4.3.1.2 Individualization ..........................................................................................119 4.3.1.3 Personalization .............................................................................................121 4.3.2 Personal Fabrication, Self Customization...............................................................124 4.3.3 Distributed Customized Production – Coproducing .............................................126 4.4 Conclusion .............................................................................................................................126 4.5 Questions ................................................................................................................................127 5 Materials, Design, and Quality Aspects for Additive Manufacturing ......129 5.1 Materials for AM ...................................................................................................................129 5.1.1 Anisotropic Properties ...............................................................................................130 5.1.2 Basic Isentropic Materials ........................................................................................133 5.1.2.1 Plastics ...........................................................................................................134 5.1.2.2 Metals .............................................................................................................136 5.1.2.3 Ceramics ........................................................................................................138 5.1.2.4 Composites ....................................................................................................138 5.1.3 Graded and Composite Materials.............................................................................139 5.2 Engineering Design Rules for AM .....................................................................................140 5.2.1 Tolerances – Digital to Object...................................................................................140 5.2.2 Design Freedom ..........................................................................................................141 5.2.3 Relative Fit ...................................................................................................................141 5.2.4 Flexures, Hinges, and Snap-Fits ..............................................................................142 5.2.5 Orientation and Clamping ........................................................................................143 5.2.6 Drillings (Bores), Gaps, Pins, and Walls .................................................................145 5.3 AM Properties, Selection, Build Management .................................................................147 5.4 Conclusion .............................................................................................................................148 5.5 Questions ................................................................................................................................148 Glossary: Terms and Abbreviations ................................................................151 Index ...................................................................................................................161 1 Basics, Definitions, and Application Levels Chapter 1 will provide a brief overview of what is called Additive Manufacturing (AM) and the principle of layer-based technology including the main definitions. Throughout this book we will approach the topic from the viewpoint of the applicator and will focus on the industrial applications of AM. Process details will be discussed in Chapter 2. All definitions are linked to a step-by-step elaboration of the “AM Application Sheet” which summarizes the definitions and interdependencies of the various applications, all of which will be illustrated by typical examples. The final version of the “AM Application Sheet” (identical with Fig. 1.19) is shown below. Additive Manufacturing (AM) Application Sheet: Technology – and Application Level Definitions 2 1 Basics, Definitions, and Application Levels ■■1.1■ Basics and Definitions 1.1.1■ Additive Manufacturing – Layer Manufacturing “Additive Manufacturing” (AM) is a layer-based automated fabrication process for making scaled 3-dimensional physical objects directly from 3D-CAD data without using part-depending tools. It was originally called “3D Printing” and is still frequently called that. Together with the well established “Subtractive Manufacturing”, such as milling or turning, and the “Formative Manufacturing”, such as casting or forging, Additive Manufacturing provides the third supporting pillar of the entire manufacturing tech- nology /Bur93/. When the first approaches to “Additive Manufacturing” entered the market in 1987, it was called “Rapid Prototyping” or “Generative Manufacturing”. Both terms are still in use and in the past years many different names have been presented and frequently more are added. Although each of the names is perfect from the special viewpoint of its creator, many of them cause confusion. Often, this is one reason why newcomers to the industry in particular sometimes feel lost in the field of AM. To obtain a brief overview, a small selection of the mostly used terms are structured according to a few families of key words. Often used terms include: ƒ “additive” Additive Manufacturing (AM) Additive Layer Manufacturing (ALM) Additive Digital Manufacturing (DM) ƒ “layer” Layer Based Manufacturing Layer Oriented Manufacturing Layer Manufacturing ƒ “rapid” Rapid Technology Rapid Prototyping, Rapid Tooling, Rapid Manufacturing ƒ “digital” Digital Fabrication Digital Mock-Up ƒ “direct” Direct Manufacturing, Direct Tooling ƒ “3D” 3D Printing, 3D Modeling Any and all imaginable (and even not imaginable) combinations of these keywords are existing too. Attention: Some of these terms are under copyright protection! There are additional terms in use that are created according to new and innovative manufacturing technologies, they include: 1.1 Basics and Definitions 3 ƒ Desktop Manufacturing ƒ On-Demand Manufacturing ƒ Freeform Manufacturing As Additive Manufacturing (AM) is a comparably young technology, there were almost no efforts for standardization for many years other than some preliminary work in Germany in the early 1990s. In 2007, a special recommendation dedicated to Rapid Prototyping /VDI3404/ was created under the supervision of the German Society of Mechanical Engineers, VDI. It was published in autumn of 2008. As of 2009, the American Society of Mechanical Engineers (ASME) in cooperation with the American Society for Testing and Materials (ASTM) started the development of their own standardization proce- dures. In autumn 2009, the committee F42 on Additive Manufacturing (subcommittee F42.91 on Terminology) issued F2792-09e1 /F2792/, also called Standard Terminology for Additive Manufacturing Technologies. Among other definitions, the name “Additive Manufacturing” was defined by this committee. As it always takes time until newly defined terms are generally accepted, a great varity of different terms, increased by brand names and company driven terms, are still in use, sometimes even in competition to each other. 1.1.2■ The Principle of Layer-Based Technology The term additive manufacturing, like “Generative Manufacturing”, covers any imag- inable way of adding material in order to create a 3-dimensional physical part. The technical realization of AM is based solely on layers and therefore it is called “layer-based technology”, “layer-oriented technology”, or even “layered technology”. Consequently, today the terms, additive manufacturing, generative manufacturing, and layer-based technology are used synonymously. In the future, as new additive technologies may become available they will need to be classified within the current structure of AM definitions. As an example, a process called “Ballistic Particle Manufacturing, BPM” was introduced already in the early 1990s, but vanished soon after. It added material from all spatial directions by jetting discrete volumes (voxels) on the emerging object. This technology was additive but not layer-based. The principle of layer-based technology is to compose a 3-dimensional physical object called “part” from many layers of (mostly) equal thickness. Each layer is contoured according to the corresponding 3-dimensional data set (see Fig. 1.1) and put on the top of the preceding one. As a consequence of the even layer thickness, the resulting part shows a stair-stepping effect as shown in Fig. 1.1, (right).