Brent Stucker

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Throughout this book we have discussed geometric accuracy, surface finish, and property limitations of AM. When a part comes out of an AM machine, there may still be a number of processes to be carried out before it can be considered ready for use. This may include subtractive manufacturing, material treatments, or coatings. This chapter discussed...

Since 2010, Additive Manufacturing has gone from a niche prototyping technology primarily known to the manufacturing, design, and engineering communities to a technology that is widely known to the general population as “3D Printing.” Much of this growth in awareness is due to an increase in the adoption of the technology due to massive reductions...

The unique attributes of Additive Manufacturing offer opportunities for new types of business enterprises. These opportunities include new types of products, organizations, and employment. In this chapter we focus our discussion on how Additive Manufacturing disrupts conventional thinking and enables a new type of entrepreneurship, called “digipron...

Printing technologies progressed rapidly as the adoption of personal computers spread through offices and homes. Inkjet printing, in particular, is a huge market, and billions of dollars have been invested to make inkjet print heads reliable, inexpensive, and widely available. As a result of advances in inkjet printing technologies, many applicatio...

Although there are an increasing number of AM technologies and variants, they nearly all use a similar process chain. This eight-step process is introduced in this chapter, which aims to provide a framework for the rest of the book. Later chapters address specific process stages in much more detail, leading to ways of overcoming inherent problems w...

The technology described in this book was originally referred to as Rapid Prototyping. The term Rapid Prototyping (or RP) is used to describe a process for rapidly creating a system or part representation before final release or commercialization. The emphasis is on creating something quickly for use as a prototype or basis model from which further...

Additive Manufacturing is in its fourth decade of commercial technological development. Over that time, we have experienced a number of significant changes that have led to improvements in accuracy, better mechanical properties, a broader range of applications, and reductions in costs of machines and the parts made by them. In this chapter, we expl...

This chapter discusses how Additive Manufacturing can be used to develop tooling solutions. Although AM is not well-suited to high-volume production for many types of geometries and materials, it does have unique benefit when producing tools for traditional volume manufacturing operations. This can be from the perspective of using AM to create patt...

Photopolymerization processes make use of liquid polymers that react to radiation to become solid. This reaction is called photopolymerization, and liquids which photopolymerize are known as photopolymers. Photopolymers are widely applied in coating and printing industries, as well as for other purposes. Stereolithography was the first type of Vat...

Sheet Lamination (SHL) was one of the earliest commercialized AM techniques, but it has had only limited success in the marketplace. In SHL, sheets of materials are cut, stacked, and bonded (not always in that order) to form an object, and the material not used in the part cannot be easily reused and is typically discarded. Sheet material, however,...

It is important to understand that AM was not developed in isolation from other technologies. It would not be possible for AM to exist were it not for innovations in areas like 3D graphics and Computer-Aided Design software. This chapter highlights some of the key moments that catalogue the development of Additive Manufacturing. It describes how th...

The benefits and drawbacks of Additive Manufacturing Technologies enable designers to think beyond traditional design for manufacture and assembly constraints. AM has unique geometric, material, and customization benefits not provided by other production techniques. Likewise, AM has need for supports, typically produces anisotropic properties, and...

As manufacturing systems have evolved from manual to powered to automated processes over the past 200 years, it is common to find examples of multiple manufacturing systems combined into a single, hybrid machine to increase manufacturing efficiencies for certain categories of parts. In additive manufacturing, this trend is also accelerating. The mo...

Powder Bed Fusion (PBF) was one of the earliest and remains one of the most versatile AM processes, being well-suited for polymers and metals and, to a lesser extent, ceramics and composites. There are an increasing number of machine variants for fusing powders using different energy sources. The most active area of development is for metal PBF pro...

Good materials are crucial for effective AM, and different processes require these materials to be prepared in different ways. Some AM processes are capable of processing a wider range of materials than others. In this chapter we look at metals, ceramics, polymers, and composites and in particular how they change throughout AM processing. Ceramics...

Binder Jetting (BJT) methods were developed in the early 1990s, primarily at MIT. They developed what they called the 3D Printing (3DP) process in which a binder is printed onto a powder bed to form part cross-sections. This concept can be compared to Powder Bed Fusion (PBF), where a laser melts powder particles to define a part cross-section. A wi...

AM processes, like all material processing, are constrained by material properties, speed, cost, and accuracy. The performance capabilities of AM materials and machines may lag behind conventional manufacturing technology (e.g., injection molding) for mass production of identical geometries, but it can outperform traditional manufacturing for small...

This chapter deals with software that is commonly used for Additive Manufacturing. In particular, we will discuss the STL file format that is used by most machines for model input data. These files are manipulated in a number of machine-specific ways to create slice data and for support generation. Basic principles of STL files are covered here inc...

Material Extrusion (MEX) machines have, by far, the largest install base of any AM technology. Inexpensive machines are sold to hobbyists at hardware stores, like Home Depot, and through multiple vendors on Amazon. Higher-end industrial machines are available through dozens of companies. While there are other techniques for creating an extrusion, h...

Direct Write (DW) technologies are a collection of AM and related approaches for creation of very small components. Most of these approaches were covered in prior chapters. However, since feature creation at very small scales brings unique challenges and benefits, it is appropriate to address this topic separately. In particular, there are increasi...

Directed Energy Deposition (DED) is a method for melting material as it is being deposited layer-by-layer. Material in wire or powder form is delivered along with the energy required to melt it. Although it has been shown that a number of material types can be processed this way, DED is almost exclusively applied to metals in both research and comm...

From the mid-1980s to the present, the percentage of parts made from Additive Manufacturing that are used as final, production parts has consistently increased. For the first decade of AM, commercial focus was on prototyping. During the second decade of AM, a significant amount of work went into illustrating the benefits of AM for producing tooling...

v Abstract Thank you for taking the time to read this textbook on Additive Manufacturing (AM). We hope you benefit from the time and effort it has taken putting it together and that you think it was a worthwhile undertaking. It all started as a discussion at a conference in Portugal when we realized we were putting together books with similar aims...

In this study, micro-computed tomography (CT) is utilized to detect defects of Ti-6Al-4V specimens fabricated by selective laser melting (SLM) and electron beam melting (EBM), which are two popular metal additive manufacturing methods. SLM and EBM specimens were fabricated with random defects at a specific porosity. The capability of micro-CT to ev...

Selective laser melting (SLM) is an attractive technology for fabricating complex metal parts with reduced number of processing steps compared to traditional manufacturing technologies. The main challenge in its adoption is the variability in mechanical property produced through this process. Control and understanding of microstructural features af...

The particle size distribution and powder morphology of metallic powders have an important effect on powder bed fusion based additive manufacturing processes, such as selective laser melting (SLM). The process development and parameter optimization require a fundamental understanding of the influence of powder on SLM. This study introduces a pre-al...

Selective Laser Melting (SLM) of a high strength low alloy steel HY100 is considered in the present investigation. The current work describes (i) optimization of SLM process parameters for producing fully dense parts in HY100 steel and (ii) the effects of post-processing heat treatment on the microstructure and mechanical properties. Samples have b...

The present work explores the feasibility of fabricating porous 3D parts in TiAl intermetallic alloy directly from Ti–6Al–4V and Al powders. This approach uses a binder jetting additive manufacturing process followed by reactive sintering. The results demonstrate that the present approach is successful for realizing parts in TiAl intermetallic allo...

The objective of this study was to provide guidance on material specifications for powders used in laser powder bed fusion based additive manufacturing (AM) processes. The methodology was to investigate how different material property assumptions in a simulation affect meltpool prediction and by corrolary how different material properties affect me...

Cobalt chromium is widely used to make medical implants and wind turbine, engine and aircraft components because of its high wear and corrosion resistance. The ability to process geometrically complex components is an area of intense interest to enable shifting from traditional manufacturing techniques to additive manufacturing (AM). The major reas...

The microstructures of dissimilar metal welds between 9Cr-1Mo (Modified) (P91) and austenitic stainless steel (AISI304) with Ni-based alloy interlayers (Inconel 625, Inconel 600 and Inconel 800H) are reported. These interlayers were deposited by the friction surfacing method one over the other on P91 alloy, which was finally friction welded to AISI...

A novel multiscale thermal analysis numerical tool has been developed to address the micro–macro interactions involved in localized melting and sintering processes, such as laser sintering of metals exhibiting nonlinear thermal response. The method involves extension of a feed-forward dynamic adaptive mesh refinement and derefinement finite-element...

Metallic powders are used as raw materials in the Selective Laser Melting (SLM) process. These metal powders are typically available from more than one powder vendor. Even when powders have the same nominal chemical compositions, powders produced by different companies typically result in different powder particle size distributions and morphologie...

Cellular structures are widely used in many engineering applications, because of their light weight, high strength-to-weight ratio, high energy absorption, etc. Many previous research and development works are largely focused on structural design, while the material properties are often over-simplified. In this work, the relationships between proce...

A novel multiscale thermal analysis framework has been formulated to extract the physical interactions involved in localized spatiotemporal additive manufacturing processes such as the metal laser sintering. The method can be extrapolated to any other physical phenomenon involving localized spatiotemporal boundary conditions. The formulated framewo...

This study evaluates the mechanical properties of Ti-6Al-4 V samples produced by selective laser melting (SLM) and electron beam melting (EBM). Different combinations of process parameters with varying energy density levels were utilized to produce samples, which were analyzed for defects and subjected to hardness, tensile, and fatigue tests. In SL...

In this study, an overview of the computational tools developed in the area of metal-based additively manufactured (AM) to simulate the performance metrics along with their experimental validations will be presented. The performance metrics of the AM fabricated parts such as the inter- and intra-layer strengths could be characterized in terms of th...

Selective laser melting (SLM) is an additive manufacturing (AM) process in which parts are fabricated by selectively melting regions of the surface of a metallic powder bed in a layer-by-layer fashion. Various thermal phenomena such as heat conduction, convection, radiation, melting and solidification, dynamic phase changes, and evaporation occur d...

Simulations capable of predicting the complex thermal behavior which occurs in a selective laser melting (SLM) process would help design and manufacturing engineers build more optimum designs in a reliable manner. A multiscale feed forward adaptive refinement and de-refinement (FFD-AMRD) finite element framework has been developed in response to th...

The present work presents an investigation of transverse laser modes in Selective Laser Melting (SLM). It includes detailed descriptions of process physics and various simulation tools that were developed at 3DSIM for SLM simulation. The SLM process depends on a focused laser directed towards a powder bed to selectively melt and solidify layers of...

With the rapid development of additive manufacturing (AM), high-quality fabrication of lightweight design-efficient structures no longer poses an insurmountable challenge. On the other hand, much of the current research and development with AM technologies still focuses on material and process development. With the design for additive manufacturing...

The term “Direct Write” (DW) in its broadest sense can mean any technology which can create two- or three-dimensional functional structures directly onto flat or conformal surfaces in complex shapes, without any tooling or masks [1]. Although directed energy deposition, material jetting, material extrusion, and other AM processes fit this definitio...

Additive Manufacturing (AM) technology came about as a result of developments in a variety of different technology sectors. Like with many manufacturing technologies, improvements in computing power and reduction in mass storage costs paved the way for processing the large amounts of data typical of modern 3D Computer-Aided Design (CAD) models with...

AM processes, like all materials processing, are constrained by material properties, speed, cost, and accuracy. The performance capabilities of materials and machines lag behind conventional manufacturing technology (e.g., injection molding machinery), although the lag is decreasing. Speed and cost, in terms of time to market, are where AM technolo...

This chapter deals with the software that is commonly used for additive manufacturing technology. In particular we will discuss the STL file format that is commonly used by many of the machines to describe the model input data. These files are manipulated in a number of machine-specific ways to create slice data and for support generation and the b...

Direct digital manufacturing (DDM) is a term that describes the usage of additive manufacturing technologies for production or manufacturing of end-use components. Although it may seem that DDM is a natural extension of rapid prototyping, in practice this is not usually the case. Many additional considerations and requirements come into play for pr...

One of the first commercialized (1991) additive manufacturing techniques was Laminated Object Manufacturing (LOM). LOM involved layer-by-layer lamination of paper material sheets, cut using a CO2 laser, each sheet representing one cross-sectional layer of the CAD model of the part. In LOM, the portion of the paper sheet which is not contained withi...

Directed energy deposition (DED) processes enable the creation of parts by melting material as it is being deposited. Although this basic approach can work for polymers, ceramics, and metal matrix composites, it is predominantly used for metal powders. Thus, this technology is often referred to as “metal deposition” technology.

Printing technology has been extensively investigated, with the majority of that investigation historically based upon applications to the two-dimensional printing industry. Recently, however, it has spread to numerous new application areas, including electronics packaging, optics, and additive manufacturing. Some of these applications, in fact, ha...

This chapter deals with AM technologies that use extrusion to form parts. These technologies can be visualized as similar to cake icing, in that material contained in a reservoir is forced out through a nozzle when pressure is applied. If the pressure remains constant, then the resulting extruded material (commonly referred to as “roads”) will flow...

The technology described in this book was originally referred to as rapid prototyping. The term rapid prototyping (RP) is used in a variety of industries to describe a process for rapidly creating a system or part representation before final release or commercialization. In other words, the emphasis is on creating something quickly and that the out...

The current approach for many manufacturing enterprises is to centralize product development, product production, and product distribution in a relatively few physical locations. These locations can decrease even further when companies off-shore product development, production, and/or distribution to other countries/companies to take advantage of l...

This chapter discusses how additive manufacturing can be used to develop tooling solutions. Although AM is not well suited to high-volume production in a direct digital manufacturing sense, it does have some benefit when producing volume production tools. This can be from the perspective of using AM to create patterns for parts that are required us...

Most AM processes require post-processing after part building to prepare the part for its intended form, fit and/or function. Depending upon the AM technique, the reason for post-processing varies. For purposes of simplicity, this chapter will focus on post-processing techniques which are used to enhance components or overcome AM limitations. These...

Binder jetting methods were developed in the early 1990s, primarily at MIT. They developed what they called the 3D Printing (3DP) process in which a binder is printed onto a powder bed to form part cross sections. This concept can be contrasted with powder bed fusion (PBF), where a laser melts powder particles to define a part cross section. A wide...

Media attention over additive manufacturing is at an all-time high. Much of this is to do with the vast increase in the availability of the technology due to massive reductions in the technology costs. By making it possible for individuals to afford them for their own personal use, the true potential has been, to some extent, uncovered. This chapte...

Every product development process involving an Additive Manufacturing machine requires the operator to go through a set sequence of tasks. Easy-to-use “desktop” or “3D printing” machines emphasize the simplicity of this task sequence. These desktop machines are characterized by their low cost, simplicity of use, and ability to be placed in an offic...

This book covers in detail the various aspects of joining materials to form parts. A conceptual overview of rapid prototyping and layered manufacturing is given, beginning with the fundamentals so that readers can get up to speed quickly. Unusual and emerging applications such as micro-scale manufacturing, medical applications, aerospace, and rapid...

Performance metrics for parts made using Additive Manufacturing (AM), such as inter- and intra-layer strength, are a function of the energy source, scan pattern(s) and material(s). Similarly, residual stress, surface finish and part distortion are a function of the state change of the material(s), scan pattern(s), overall geometry and post-fabricat...

The mechanical behavior and the microstructural evolution of 17-4 precipitation hardenable (PH) stainless steel processed using selective laser melting have been studied. Test coupons were produced from 17-4 PH stainless steel powder in argon and nitrogen atmospheres. Characterization studies were carried out using mechanical testing, optical micro...

The complexity of local and dynamic thermal transformations in additive manufacturing (AM) processes makes it difficult to track in situ thermomechanical changes at different length scales within a part using experimental process monitoring equipment. In addition, in situ process monitoring is limited to providing information only at the exposed su...

Selective laser melting (SLM) involves highly localized heat input and directional solidification, which enables novel microstructure control through the development of scanning strategies and related process variables. A careful study of scan pattern is important to understand microstructural evolution during SLM. In this study, various types of s...

Dental porcelain materials have been used widely in dental restorations such as crowns, veneers and onlays. In this study, a commercial dental-grade porcelain powder (IPS InLine Dentin) was investigated for compatibility with 3D printing. An extensive experimental study was carried out to evaluate the effects of various in-process and post-process...

Ti-6Al-4 V parts made using additive manufacturing processes such as selective laser melting (SLM) and electron beam melting (EBM) are subject to the inclusion of defects. This study purposely fabricated Ti-6Al-4 V samples with defects by varying process parameters from the factory default settings in both SLM and EBM systems. Process parameters ar...

This talk gives an overview of an on-going project supported by America Makes (the National Additive Manufacturing Innovation Institute) that directly targets missing links for understanding and controlling microstructure and mechanical properties across both laser powder bed (EOS) and electron beam powder bed (Arcam) processes. Establishing these...

The capabilities of additive manufacturing technologies to fabricate multi-material structures have been investigated in many studies. However, only a few of the technologies have been used to fabricate products for direct application. The full development of the capability will enable the fabrication of innovative engineering structures consisting...

In this work, Ti–6Al–4V and 15-5 PH steel samples were fabricated using selective laser melting (SLM) and their tensile, fatigue, and fracture properties were analyzed and compared. The tensile properties were compared with respect to the build orientation. The horizontally built samples showed relatively better tensile properties as compared with...

Processing parameter has an important effect on Selective Laser Melting (SLM) and Electron Beam Melting (EBM) processes. Defects are easily formed by deviating from optimized processing parameters. This study purposely fabricated Ti-6Al-4V specimens with defects by varying process parameters from the factory default settings in both SLM and EBM equ...

Energy density, which directly impacts the properties of as-built parts, is a key factor in the metal selective laser melting (SLM) process. This paper studies the influences of energy density on porosity and microstructure of SLM 17-4PH stainless steel parts. Experiments were carried out by varying processing parameters to change energy density. P...

In order to investigate the morphology of defects present in Selective Laser Melting (SLM) and Electron Beam Melting (EBM) processes, Ti-6Al-4V specimens were fabricated with varying porosity using non-optimum processing parameters. Defective specimens were sectioned and polished for microscopy. Image processing was adopted for statistically analyz...

The formation of constituent phases in Selective Laser Melting of Inconel 625 is a function of local temperatures, hold times at those temperatures, local cooling rates and local compositions in the melt pool. These variables are directly correlated with input process parameters such as beam power, scan speed, hatch spacing, beam diameter and therm...

This work compares two metal additive manufacturing processes, selective laser melting (SLM) and electron beam melting (EBM), based on microstructural and mechanical property evaluation of Ti6Al4V parts produced by these two processes. Tensile and fatigue bars conforming to ASTM standards were fabricated using Ti6Al4V ELI grade material. Microstruc...

Finite element modeling (FEM) is one of the most common methods for predicting the thermo-mechanical properties of 3D structures. Since FEM was developed primarily to analyze and optimize structures that would then be mass-produced, the time for modeling was small compared to the time required to produce the components. With the advent of Additive...

The complexity of localized and dynamic boundary conditions in additive manufacturing processes makes it difficult to track in-situ thermo-mechanical changes at different length scales within a part using experimental equipment such as a FLIR 1 system and other NDE 2 techniques. Moreover, in-situ process monitoring is limited to providing informati...