Mechanical Engineering Commons^™

The Effect Of Incorporating End-User Customization Into Additive Manufacturing Designs, Jonathan D. Ashley

Graduate Theses and Dissertations

In the realm of additive manufacturing there is an increasing trend among makers to create designs that allow for end-users to alter them prior to printing an artifact. Online design repositories have tools that facilitate the creation of such artifacts. There are currently no rules for how to create a good customizable design or a way to measure the degree of customization within a design. This work defines three types of customizations found in additive manufacturing and presents three metrics to measure the degree of customization within designs based on the three types of customization. The goal of this work …

Model-Based Predictive Analytics For Additive And Smart Manufacturing, Zhuo Yang

Doctoral Dissertations

Qualification and certification for additive and smart manufacturing systems can be uncertain and very costly. Using available historical data can mitigate some costs of producing and testing sample parts. However, use of such data lacks the flexibility to represent specific new problems which decreases predictive accuracy and efficiency. To address these compelling needs, in this dissertation modeling techniques are introduced that can proactively estimate results expected from additive and smart manufacturing processes swiftly and with practical levels of accuracy and reliability. More specifically, this research addresses the current challenges and limitations posed by use of available data and the high …

The Influence Of Build Parameters On The Compressive Properties Of Selective Laser Melted 304l Stainless Steel, Okanmisope Fashanu, Mario F. Buchely, R. Hussein, S. Anandan, Myranda Spratt, Joseph William Newkirk, K. Chandrashekhara, H. Misak, M. A. Walker

Materials Science and Engineering Faculty Research & Creative Works

Process parameters used during Selective Laser Melting (SLM) process have significant effects on the mechanical properties of the manufactured parts. In this study, the influence of two build parameters (build orientation and hatch angle) on the compressive properties of 304L stainless steel was evaluated. SLM 304L samples were manufactured using three hatch angles, 0°, 67°,105° and two orientations, z-direction and x-direction, and tested using a compression frame according to ASTM E9-09. Bulk density was measured according to ASTM C373-17 before compression. Properties evaluated were the bulk density, yield strength, strength at 15% plastic-strain and strength at 30% plastic-strain. Results showed …

Additive Manufacturing Of Metal Functionally Graded Materials: A Review, Yitao Chen, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Functionally graded materials (FGMs) have attracted a lot of research interest due to their gradual variation in material properties that result from the non-homogeneous composition or structure. Metal FGMs have been widely researched in recent years, and additive manufacturing has become one of the most important approaches to fabricate metal FGMs. The aim of this paper is to review the research progress in metal FGMs by additive manufacturing. It will first introduce the unique properties and the advantages of FGMs. Then, typical recent findings in research and development of two major types of metal additive manufacturing methods, namely laser metal …

Design Of Lattice Structures With Graded Density Fabricated By Additive Manufacturing, Wenjin Tao, Yong Liu, Austin T. Sutton, Krishna C. R. Kolan, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Lattice structures fabricated by Additive Manufacturing (AM) processes are promising for many applications, such as lightweight structures and energy absorbers. However, predicting and controlling of their mechanical behaviors is challenging due to the complexity of modeling and the uncertainties exist in the manufacturing process. In this paper, we explore the possibilities enabled by controlling the local densities. A set of lattice structures with different density gradients are designed using an implicit isosurface equation, and they are manufactured by Selective Laser Melting (SLM) process with 304L stainless steel. Finite element analysis and compression test are used to evaluate their mechanical properties. …

Development Of An Additive Manufacturing Compression Molding Process For Low Cost In-House Prototyping, Grant Forrester Warden

Industrial and Manufacturing Engineering

Composite parts can be manufactured using various processes. Generally, a mix of resin and fiber is formed into the desired geometry using a mold and pressure. One process used by Dr. Joseph Mello in his research is known as compression molding. Compression molds are generally made from large billets of aluminum or stainless steel, are machined by a CNC mill, and are then hand-finished with polishes and mold preparation products. This process is expensive, requires large machinery and experienced operators, and introduces long lead times relative to the design cycle of the part being manufactured. The nature of Dr. Mello's …

Defect Detection In Selective Laser Melting, Moira Foster

Master's Theses

Additively manufactured parts produced using selective laser melting (SLM) are prone to defects created during the build process due to part shrinkage while cooling. Currently defects are found only after the part is removed from the printer. To determine whether cracks can be detected before a print is completed, this project developed print parameters to print a test coupon with inherent defects – warpage and cracking. Data recorded during the build was then characterized to determine when the defects occurred.

The test coupon was printed using two sets of print parameters developed to control the severity of warpage and cracking. …

Mechanical Characterization Of Selectively Laser Melted 316l Stainless Steel Body Centered Cubic Unit Cells And Lattice Of Varying Node Radii And Strut Angle, Christopher James Hornbeak

Master's Theses

An experimental study of several variants of radius and strut angle of the body centered cubic unit cell was performed to determine the mechanical properties and failure mechanisms of the mesostructure. Quasi static compression tests were performed on an Instron® universal testing machine with a 50kN load cell at 0.2mm/min. The test samples were built using a SLM Solutions 125 selective laser melting machine with 316L stainless steel. Test specimens were based on 5mm cubic unit cells, with a strut diameter 10% of the unit cell size, with skins on top and bottom to provide a cantilever boundary constraint. Specimens …

Microheater Array Powder Sintering (Maps) For Printing Flexible Electronics, Nicholas Holt

Graduate Theses and Dissertations

Microheater array powder sintering (MAPS) is a novel additive manufacturing process that uses an array of microheaters to selectively sinter powder particles. MAPS shows great promise as a new method of printing flexible electronics by enabling digital curing of conductive inks on a variety of substrates. MAPS operation relies on establishing a precision air gap of a few microns between an array of microheaters, which can reach temperatures of 600°C, and a layer of conductive ink which can be deposited onto a flexible substrate. This system presents challenges, being: the fabrication of a microheater that can reach suitable temperatures in …

Reducing Stress In 3d Printed Parts Made With Laser Engineered Net Shaping, Shaun Ross Whetten

Mechanical Engineering ETDs

Thermal cycling and repeated melting/solidification cycles characteristic of 3D metal printing processes causes buildup of residual stress in 3D printed parts. Using laser engineered net shaping (LENS®), residual stresses are formed leading to deformation and possible cracking of the 3D printed metal components. The LENS process offers opportunities for rapid prototyping, alternative manufacturing processes, and repair of worn/broken components so it is important to be able to minimize the effects of residual stress. Work was performed to understand the benefit of substrate heating on reducing residual stress in metal parts made using the LENS process. Substrate deformation, and destructive methods …

Supporting Engineering Design Of Additively Manufactured Medical Devices With Knowledge Management Through Ontologies, Thomas Hagedorn

Doctoral Dissertations

Medical environments pose a substantial challenge for engineering designers. They combine significant knowledge demands with large investment for new product development and severe consequences in the case of design failure. Engineering designers must contend with an often-chaotic environment to which they have limited access and familiarity, a user base that is difficult to engage and highly diverse in many attributes, and a market structure that often pits stakeholders against one another. As medical care in general moves towards personalized models and surgical tools towards less invasive options emerging manufacturing technologies in additive manufacturing offer significant potential for the design of …

Development Of Material For 3d Printed Habitats With Extraplanetary Applications, Taylor Wait

Electronic Theses and Dissertations

3D printing, also called Additive Manufacturing, has increasingly become a focus for research because of the potential to replace complicated assemblies or complex parts with a single printed item. The space industry is very interesting in studying 3d printing with parts being tested and used on rockets, a 3D printer being installed at the International Space Station and is being developed for use in manned exploration of extraplanetary bodies to build habitats. To encourage teams from around the world to develop technologies and materials for autonomous habitat construction using minimal Earth exports, NASA created the 3D Printed Habitat Challenge. NASA …

Development Of A Desktop Material Extrusion 3d Printer With Wire Embedding Capabilities, Jose Francisco Motta

Open Access Theses & Dissertations

Printed circuit boards (PCB) have been widely used as a permanent solution for generating complex circuitries to power electronic devices. Over the years, PCB boards have proved to be reliable when powering electronic devices. However, when fabricating a printed circuit board, one must outsource to fabricate the boards when in prototype phase. Therefore, the risk of intellectual property theft and long lead time is an issue. The objective of this Thesis is to develop a hybrid multi-tool desktop material extrusion 3D printer that allows for easy integration (modularity) of tools to generate multi-functional 3D printed components.

The addition of an …

Equibiaxial Flexural Strength Testing Of Advance Ceramics, Ryan T. Jordan

Honors Undergraduate Theses

Ceramics are very important materials with many unique properties used in numerous industrial applications. Ceramics could be very hard and very strong in comparison to metals; however, they are very brittle, thus they are prone to instantaneous and catastrophic failure. Therefore, their reliability is compromised and it is very important to have advanced techniques that allow evaluating their mechanical behavior in many unusual stress states. One of such testing methods is biaxial strength method, that allows to measure properties not only unidirectional, but also in a biaxial way. The research work for this thesis will be built on design and …

Constitutive Model Development For Additive Manufacturing, Diana Berenice Montes

Open Access Theses & Dissertations

Additive manufacturing (AM) is known worldwide for revolutionizing the development of three-dimensional modeling by reducing the time and increasing the precision of parts. For Powder Bed Fusion research is necessary to reduce concerns in residual stress, porosity and cracking in AM parts. A constitutive model was created in Abaqus to validate material properties of 3D printed Al 6061. Finite element analysis was performed to investigate how properties may affect in the modification of parameters to reduce printing imperfections. Research was made as well in polylactic acid properties for material extrusion to explore its behavior for creep and relaxation. Properties were …

Development And Management Of Advanced Batteries Via Additive Manufacturing And Modeling, Jie Li

Doctoral Dissertations

"The applications of Li-ion batteries require higher energy and power densities, improved safety, and sophisticated battery management systems. To satisfy these demands, as battery performances depend on the network of constituent materials, it is necessary to optimize the electrode structure. Simultaneously, the states of the battery have to be accurately estimated and controlled to maintain a durable condition of the battery system. For those purposes, this research focused on the innovation of 3D electrode via additive manufacturing, and the development of fast and accurate physical based models to predict the battery status for control purposes. Paper I proposed a novel …

Laser-Aided Additive Manufacturing Of Glass, John Michael Hostetler

Masters Theses

“This thesis presents various approaches for the laser-aided additive manufacturing of glass. First, a technique is investigated to create free-form, low to zero coefficient of thermal expansion structures out of silica-gel. A CO₂ laser was coupled through a gantry system and focused onto a binder-free silica-gel powder bed (15-40 μm particles). Prior to writing each layer, powder is dispensed by sifting it onto the build platform as opposed to a conventional wiper system, avoiding contacting and potentially damaging sensitive parts. After deposition, the parts are annealed in a furnace to increase their strength. The influence of various process parameters …

Designed Extrudate For Ceramic Additive Manufacturing, Devin Mcmillen

Masters Theses

"The objective of this thesis work was to design ceramic paste systems that assist in achieving a high theoretical density ( > 95%) after deposition by a novel additive manufacturing process, i.e. Ceramic On-Demand Extrusion (CODE). The work is encompassed in five main sections: Sections 1 and 2 provide an introduction and literature review of relevant topics for the following sections of experimentation. Section 3 provides an analysis of a reaction chemistry to identify three discrete materials that could be combined via CODE and result in zirconium diboride (ZrB₂) post-sintering. Section 4 describes the development of a high solids …

Additive Manufacturing Of Energy Harvesting Material System For Active Wireless Mems, Victor Fernando Elicerio

Open Access Theses & Dissertations

Additive manufacturing (AM - most commonly known as 3D printing) is a fabrication method and aims to increase production efficiency while lowering costs of constructing quality components for industry application when compared to traditional machining. In addition to this, AM possesses capabilities that far exceed machining as complex geometries are achievable through an array of technologies in a wide variety of materials. The AM process begins with a computer aided design (CAD) which creates a design path for a 3D printer to follow. By following this path, components are built from bottom to top in a layer by layer fashion. …

Predictive Modeling On The Piezoelectric Properties Of 3d Printed Functional Nanocomposites Using The Data Analytics Approach, Md Didarul Islam

Open Access Theses & Dissertations

This paper presents research done on prediction modeling using a data analytics approach to determine various factors affecting the piezoelectric properties of the 3D printed pressure sensors. Previously, the material extrusion 3D printing technique was used to fabricate pressure sensors composed of multiwall carbon nanotubes (CNT), barium titanate (BT), and polyvinylidene fluoride (PVDF) using simple fabrication and low-cost methods. This sensor produced a voltage output of 725 mV (0.13 pC/N) which is enough for pressure sensing applications. However, a holistic study to determine impacts of all factors was not carried out in the previous model. In this study, the design …

Design And Optimization Of A 1 Kw Stirling Engine, Garrett Tyler Rinker

Graduate Theses, Dissertations, and Problem Reports

Stirling engines are often overlooked as a means of energy conversion, though its versatility offers many advantages. Since it is an external combustion engine, it can be supplied with heat through the combustion of a variety of fuels. Its maintenance- and degradation-free aspects, as well as its excellent turn down ratio, make it a suitable candidate for applications such as remote power generation, combined heat and power (CHP), cryogenics, solar power, and even space exploration. The continual advancement of additive manufacturing (AM) offers opportunity to potentially further improve the already efficient Stirling cycle. This dissertation presents the design and optimization …

Fabrication And Characterization Of Advanced Materials Using Laser Metal Deposition From Elemental Powder Mixture, Xueyang Chen

Doctoral Dissertations

"Over the past decades of years, a great deal of money has been spent to machine large and complex parts from high-performance metals (i.e., titanium components for aerospace applications), so users attempt to circumvent the high cost of materials. Laser metal deposition (LMD) is an additive manufacturing technique capable of fabricating complicated structures with superior properties. This dissertation aims to improve the applications of LMD technique for manufacturing metallic components by using various elemental powder mixture according to the following three categories of research topics. The first research topic is to investigate and develop a cost-effective possibility by using elemental …

Laser Foil Printing And Surface Polishing Processes, Chen Chen

Doctoral Dissertations

"A foil-based additive manufacturing technology for fabricating metal parts, called Laser Foil Printing (LFP), was proposed and developed in this dissertation. The manufacturing sub-processes comprising the LFP technology were comprehensively studied, which include the laser spot welding of foil, laser raster-scan welding of foil, laser cutting of foil, and laser polishing processes. The fabricated free-form parts were demonstrated and own better mechanical properties (micro hardness and tensile strength) than the raw material, because of the rapid-cooling process of laser welding. The full and strong bond between layers was formed by the laser welding process, with no micro-cracks or pores observed. …

Research On Additive Manufacturing Of Metallic Glass Alloy, Yiyu Shen

Doctoral Dissertations

"The required rapid cooling has limited the dimension of the Bulk Metallic glasses (BMGs) produced by traditional method, and hence has seriously limited their applications, despite their remarkable mechanical properties. In this present project, a detailed study is conducted on the methodology and understanding of manufacturing large Zr- based metallic glass part by laser based additive manufacturing technology, which breaks the size limitation. The first research issue proposes and develops a new additive manufacturing technology, named Laser-Foil-Printing (LFP). Sheet foils of LM105 (Zr_52.5Ti₅Al₁₀Ni_14.6Cu_17.9 (at. %)) metallic glass are used as feed …

Investigation Of Microstructure And Mechanical Properties By Direct Metal Deposition, Jingwei Zhang

Doctoral Dissertations

"Microstructure and properties of Direct Metal Deposition (DMD) parts are very crucial to meeting industrial requirements of parts quality. Prediction, and control of microstructure and mechanical properties have attracted much attention during conventional metal manufacturing process under different conditions. However, there is few investigations focused on microstructure simulation and mechanical properties control under different process parameters during DMD process. This dissertation is intended to develop a multiscale model to investigate Ti6Al4V grain structure development and explore Ti6Al4V based functionally graded material (FGM) deposit properties during DMD process. The first research topic is to investigate and develop a cellular automaton-finite element …