Additive Manufacturing, Second Edition

Amit Bandyopadhyay, Susmita Bose, Amit Bandyopadhyay, Susmita Bose

• Publisher: CRC Press
• Year: 2019
• ISBN:
  9780429881015
• Edition: 2
• Topic: Tecnología e ingeniería
• Subtopic: Ingeniería eléctrica y telecomunicaciones

The field of additive manufacturing is growing dynamically as the interest is persisting from manufacturing sector, including other sectors as well. Conceptually, additive manufacturing is a way to build parts without using any part-specific tooling or dies from the computer-aided design (CAD) file of the part. Second edition of Additive Manufacturing highlights the latest advancements in the field, taking an application oriented approach. It includes new material on traditional polymer based rapid prototyping technologies, additive manufacturing of metals and alloys including related design issues. Each chapter comes with suggested reading, questions for instructors and PowerPoint slides.

1	Introduction to Additive Manufacturing Amit Bandyopadhyay, Thomas Gualtieri, Bryan Heer, and Susmita Bose

CONTENTS

1.1 Introduction

1.2 History of AM

1.2.1 Start of 3D Printing

1.2.2 Development of Other RP Technologies

1.2.3 Moving from RP to AM

1.2.4 Impact of AM

1.3 Current Manufacturing Challenges

1.3.1 Part-versus Systems-Level Manufacturing

1.3.2 Centralized and Projection-Based Manufacturing Issues

1.3.3 Generalized Designs: Consumer Settling for Only Adequate Products

1.4 AM: Unparalleled Manufacturing Paradigm

1.4.1 Current State of AM and How It Generally Works

1.4.2 Advantages of AM: No Restriction on Design

1.4.3 Advantages of AM: Versatility in Manufacturing

1.4.4 Advantages of AM: Altering Materials for Enhanced Performance

1.4.5 AM Already Incorporated into Modern Manufacturing

1.4.6 Evolution of CAD to AM and Its Influence on Manufacturing

1.5 Global Engineering and AM

1.5.1 Moving from Localized to Globalized Engineering

1.5.2 Engineer from Anywhere in the World Efficiently and Effectively

1.5.3 Manufacturing in Space: No Longer a Dream

1.6 Future Trends

1.6.1 On-Demand Manufacturing of Custom Products

1.6.2 Allowing People’s Creativity to Become a Reality

1.6.3 Personal AM Machines as a Standard Household Application

1.6.4 AM Advancing Medical Technology and Helping Lives

1.6.5 AM of Bi-Metallic and Multi-Material Structures

1.7 Summary

Problems

References

1.1 INTRODUCTION

Additive manufacturing (AM) is a technology that is rapidly developing and is being integrated into manufacturing and also our day-to-day lives. Its emergence into the commercial world has been labeled by a variety of names, such as three-dimensional (3D) printing, rapid prototyping (RP), layered manufacturing (LM), or solid freeform fabrication (SFF). Conceptually, AM is an approach where 3D designs can be built directly from a computer-aided design (CAD) file without any part-specific tools or dies. In this freeform layer-wise fabrication, multiple layers are built in the X-Y direction on top of one another to generate the Z or 3rd dimension. Once the part is built, it can be used for touch and feel concept models, tested for functional prototypes, or used in practice. The everyday consumer should realize that AM can be a way to connect with manufacturers on a new level. AM is much more than a process that can be used to make personalized novel items or prototypes. With new developments in AM, we live in an age that is on the cusp of industrialized rapid manufacturing taking over as a process to mass produce products and make it economically feasible to design and create new ones in a timely fashion. As a result, the manufacturing process of sectors across the globe will adapt to these developments while incorporating a new style of customer–manufacturer interaction. AM allows people to contribute to the design process from almost any location at all and will break the barriers of localized engineering and emerge on a global scale. Just as the Internet has given us the ability to spread and access information from any location at all, digital designing and CAD have given people the ability to make, change, and critique designs from anywhere. With AM, those designs can be made and tested from almost any location at all with very little lead time. The capabilities of AM machines have become sophisticated to a point where thinking of the design and drafting the model in CAD is the limitation instead of the manufacturability of the product.¹ As a new generation grows up with CAD technology and the abilities and availability of AM machines grow, the process of designing a product will mature from being created by a select group of engineers to being created by the consumer and company together, with the final product being able to be manufactured anywhere in the world in a timely manner.

1.2 HISTORY OF AM

1.2.1 START OF 3D PRINTING

AM was first developed in the 1980s when a man named Charles “Chuck” Hull invented the first form of 3D printing called stereolithography (SLA). It was the advancements in laser technology, along with Mr. Hull’s innovation on the materials and process that he used, that first made this conceptual method a reality.² Stereolithography is a system where an ultra-violet (UV) light source is focused down into an UV photo-curable liquid polymer bath, where, upon contact, the polymer hardens. Patterns can be drawn using the ultra-violet source to semi-cure the polymer layer. Uncured polymer stays in the bath and provides support to the part that is being built. After a layer of printing is done, the hardened polymer layer moves down on a build plate in the liquid medium, and the next layer of polymer is available on top for the following layer. This process continues until the part is finished based on the CAD design and is removed from the liquid medium. In most cases, further curing is needed before the part can be touched. It was in 1983 when Chuck Hull invented this new technology, and, subsequently, in 1986, he formed the very first company to develop and manufacture 3D printers called 3D Systems.² This was the first step in the history of making an RP machine outside of science fiction movies or books. Mr. Hull was also the first to devise a way to allow CAD files to communicate with the RP system in order to build computer modeled parts. Such an endeavor was not trivial. To accomplish this, 3D CAD models had to be sliced in a virtual world, and then each slice could be used to build a layer using the 3D printer. In the first-generation CAD files for 3D printers, only the surface files mattered, which were termed. stl files from the stereolithography process. After developing this technology, the patent application was filed in August 1984 and was approved in 1986 by the United States Patent and Trademark Office (USPTO), making it the first patent of an RP system.³ Though Chuck Hull patented this technology in 1986, it took several years for 3D Systems to launch the first solid state stereolithography system.²

1.2.2 DEVELOPMENT OF OTHER RP TECHNOLOGIES

While 3D Systems was developing and patenting this technology, other innovators started to develop new types of AM machines that used different methods and materials. At the University of Texas at Austin, an undergraduate student named Carl Deckard and an assistant professor Dr. Joe Beaman started working on a new technology known as selective laser sintering (SLS). SLS worked by first spreading powdered material on a build plate where a laser selectively sintered the powder in certain areas of the plate. Another layer of powder was then distributed over the previous layer and the process was repeated. In the end, the powder from each layer was sintered together in overlapping regions to produce the 3D part. Deckard and Dr. Beaman started working on this technology in 1984 and made the first SLS machine in 1986. They then commercialized the technology, creating the first SLS company called Nova Automation, which later became DTM Corp. In 1989, they made the first commercial machines which were called Mod A and Mod B, and they continued advancing and making more SLS machines until the company was sold to 3D Systems in 2001.⁴

Around the same time, Scott Crump and his wife Lisa, both graduates of Washington State University, were developing another AM technology in their garage. Scott wanted to make a toy for his daughter, so he invented the technology referred to as fused deposition modeling (FDM).⁵ This technology involved the heating of a thermoplastic to a semi-liquid state, which was then deposited onto a substrate where it built the part layer by layer.⁶ Scott and Lisa went on to start the company Stratasys, Inc. in 1989, selling this technology, in addition to having it patented in 1992.^7,8 Stratasys, Inc. has continued to grow, and the company now is a leader in polymer 3D printing with many printers in markets ranging from commercial industry to educational.

At the same time, another man named Roy Sanders was developing a new RP method. His company, formerly known as Sanders Prototype Inc., now named Solidscape^®, released its first 3D printer called the ModelMaker™ 6 Pro in 1994.⁹ This machine used an inkjet approach to build a part.¹⁰ This method essentially acts the same as stereolithography, but instead of a laser being focused into a liquid medium, hot thermoplastic wax liquid is sprayed onto a plate to build each layer of a part. This machine could make high resolution wax models which were very popular for businesses that perform complex investment casting such as the jewelry industry.¹¹ The company experienced commercial success and was later bought by Stratasys, Inc. in May of 2011.¹²

The above mentioned are just some of the original RP systems that were being developed at that time, yet these founders were not the only people who saw the significance of these technologies. Once 3D Systems patented stereolithography, companies in other countries started to develop this technology as well. In Japan, two companies called NTT Data CMET and Sony/D-MEC started to develop stereolithography systems in 1988 and 1989, respectively.¹³ In addition, companies in Europe such as Electro Optical Systems (EOS) and Quadrax developed stereolithography systems in 1990.¹³ Many companies around the globe were starting to develop their own 3D printing devices and coming up with unique ways to improve the process. It was...