Mechanical Engineering Commons^™

Additive Manufacturing Of Dense We43 Mg Alloy By Laser Powder Bed Fusion, Holden Hyer, Le Zhou, George Benson, Brandon Mcwilliams, Kyu Cho, Yongho Sohn

Mechanical Engineering Faculty Research and Publications

WE43 is a high-strength, corrosion-resistant Mg-alloy containing rare earths such as Y and Nb, and has potential for many lightweight structural or bioresorbable prosthetic applications. In this study, additive manufacturing of dense WE43 alloy by laser powder bed fusion (LPBF) from gas atomized powders has been accomplished through studies involving single track scan of wrought WE43, parametric variation of LPBF, microstructural analysis and mechanical testing, both in compression and tension. The Archimedes method and image analyses from optical micrographs were employed to document the LPBF of dense (>99 % relative density) WE43 using optimum parameters of 200 W laser …

Selective Laser Melting 17-4 Ph Stainless Steel And The Effect Of Varied Thermal Treatments On Fatigue Behavior., Sean Daniel Dobson

Electronic Theses and Dissertations

Fatigue failure is the leading source of loss in industry. In order for new means of manufacturing to move towards mainstream use a complete understanding of material and mechanical behavior must be gained. This endeavor seeks to aide in that task by observing the fatigue behavior of selective laser melting (SLM) additive manufacturing (AM) specimens and the effect of differing thermal treatment conditions for an optimized AM process. Stainless steel 17-4 PH specimens were fabricated using SLM AM and thermally treated to three conditions: as-built, solutionized and hardened, and direct hardened. These specimens were characterized for material (powder quality, density, …

Influences Of Material Extrusion Additive Manufacturing (Meam) Parameters And Additives On Polyvinylidene Fluoride (Pvdf) Properties., Niknam Momenzadeh

Electronic Theses and Dissertations

Beyond the beneficial characteristics of smart polymers associated with all polymers such as flexibility and cost fabrication, smart materials exhibit multifunctional behaviors. The prospect of integrating structural and sensing/actuation capabilities into a single structure gives design engineers an ability to innovate highly novel, multi-functional creations. Polyvinylidene Fluoride (PVDF) is one of the widely used multi-functional materials which offers a variety of desirable material properties. It possesses exceptional chemical and UV resistance, biocompatibility, low processing temperature and affordable price making it a competitive choice for many commercial applications. In addition, among polymers, PVDF is simply the most dominant piezoelectric polymer. On …

Impact Of Part Thickness And Drying Conditions On Saturation Limits In Binder Jet Additive Manufacturing, Nathan B. Crane

Faculty Publications

Binder jetting (BJ) is a high build-rate additive manufacturing process with growing commercial interest. Growth in BJ applications is driven by the use of finer powders and improved post-processing methods that can produce dense, homogenous final parts. However, understanding of the basic droplet/powder interaction is relatively limited. This paper considers the impact of in-process drying, part geometry, and droplet size on a key printing parameter: binder saturation. Parts of varying thicknesses are printed with a range of saturation levels under various heating conditions. The ratio of the printed part mass to the theoretical part mass is used to detect bleeding. …

Aluminum Parts Fabricated By Laser-Foil-Printing Additive Manufacturing: Processing, Microstructure, And Mechanical Properties, Chia Hung Hung, Yingqi Li, Austin Sutton, Wei Ting Chen, Xiangtao Gong, Heng Pan, Hai Lung Tsai, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Fabrication of dense aluminum (Al-1100) parts (>99.3% of relative density) by our recently developed laser-foil-printing (LFP) additive manufacturing method was investigated as described in this paper. This was achieved by using a laser energy density of 7.0 MW/cm2 to stabilize the melt pool formation and create sufficient penetration depth with 300 μm thickness foil. The highest yield strength (YS) and ultimate tensile strength (UTS) in the LFP-fabricated samples reached 111 ± 8 MPa and 128 ± 3 MPa, respectively, along the laser scanning direction. These samples exhibited greater tensile strength but less ductility compared to annealed Al-1100 samples. Fractographic …

Thermal Modeling Of Coordinated Multi-Beam Additive Manufacturing, Rachel Elizabeth Evans

Browse all Theses and Dissertations

In additive manufacturing (AM), it is necessary to know the influence of processing parameters in order to have better control over the microstructure and mechanical performance of the part. Laser powder bed fusion (LPBF) is a metal AM process in which thin layers of powdered material are selectively melted to create a three-dimensional structure. This manufacturing process is beneficial for many reasons; however, it is limited by the thermal solidification conditions achievable in the available processing parameter ranges for single-beam processing methods. Therefore, this work investigates the effect of multiple, coordinated heat sources, which are used to strategically modify the …

In-Situ X-Ray Imaging Of The Selective Laser Melting Process, Meelap M. Coday

Masters Theses

"Fusion-based metal additive manufacturing (AM) has garnered much interest in recent decades. Despite the popularity of fusion-based AM technologies such as selective laser melting (SLM), there are still fundamental questions and uncertainties that need to be addressed. In this work, we focus on the understanding of the undercooling in the SLM process and the uncertainties induced by the laser beam size, power, and scan speed. First, we report the estimation of undercooling in the SLM process from the solidification rate measured by in-situ high-speed synchrotron x-ray imaging, based on the dendrite growth velocity model. The undercooling changes as a function …

Combining Laser Aided Ablation And Polishing To Minimize Surface Roughness Of Additively Manufactured Aluminium Components, Sahil Bipinkumar Patel

Masters Theses

“The surface roughness of additively manufactured parts is much higher than the acceptable range for most applications, thus post-processing is needed to qualify these parts for use. Laser polishing can be used to bring the surface roughness in an admissible range, but if the initial roughness is very high then the energy density for the polishing process needs to be very high to achieve a significant reduction in roughness. This high energy density can produce many process defects. Also, laser polishing alone cannot get rid of high wavelength asperities. Any waviness in the part can be linked with initial waviness …

Synthesis And Advanced Manufacturing Of Polymer Structures And Their Composites, Bethany Rose Wilburn

Open Access Theses & Dissertations

The following research work performed embodies three unique studies of polymer structures and their composites. In general, polymers are viscoelastic, insulative materials that are used for a wide variety of applications within industrial, aerospace, and biomedical fields. Polymers have been studied and optimized for any particular use by chemically synthesizing unique micro-structures, altering the physical properties through fabrication and post-processing, and utilizing 3D printing to achieve complex geometries. In the past decade, additive manufacturing (AM) has drawn extensive attention across academia, industry, and government agencies. It offers unprecedented advantages such as design freedom, rapid prototyping, and customization. In this work, …

Defect Modeling And Vibration-Based Bending Fatigue Of Additively Manufactured Inconel 718, Wesley Earl Eldt

Browse all Theses and Dissertations

Additive manufacturing (AM) is convenient for building components with complex features. However, the long-term integrity of these components is uncertain, since AM parts have defects such as pores and rough surfaces. In this work, an analytical model was developed to determine the impact of defects, and a novel bending fatigue test was used to determine the fatigue life of channeled specimens. The analytical model, based off the theory of critical distances, investigates coupled pores and predicts their potential for fatigue failure. This resulted in a maximum allowable pore size and spacing recommendation for coupled defects. Additionally, specimens with through channels …

Additive Manufacturing Of Magnesium Alloys, Rakeshkumar Karunakaran, Sam Ortgies, Ali Tamayol, Florin Bobaru, Michael P. Sealy

Department of Mechanical and Materials Engineering: Faculty Publications

Magnesium alloys are a promising new class of degradable biomaterials that have a similar stiffness to bone, which minimizes the harmful effects of stress shielding. Use of biodegradable magnesium implants eliminates the need for a second surgery for repair or removal. There is a growing interest to capitalize on additive manufacturing's unique design capabilities to advance the frontiers of medicine. However, magnesium alloys are difficult to 3D print due to the high chemical reactivity that poses a combustion risk. Furthermore, the low vaporization temperature of magnesium and common biocompatible alloying elements further increases the difficulty to print fully dense structures …

Influence Of Droplet Velocity, Spacing, And Inter-Arrival Time On Line Formation And Saturation In Binder Jet Additive Manufacturing, Trenton Colton, Nathan B. Crane

Faculty Publications

Binder Jetting (BJ) is a low-cost Additive Manufacturing (AM) process that uses inkjet technology to selectively bind particles in a powder bed. BJ relies on the ability to control, not only the placement of binder on the surface but also its imbibition into the powder bed. This is a complex process in which picoliter-sized droplets impact powder beds at velocities of 1-10 m/s. However, the effects of printing parameters such as droplet velocity, size, spacing, and inter-arrival time on saturation level (fraction of pore space filled with binder) and line formation (merging of droplets to form a line) are unknown. …

Fabrication And Characterization Of Multifunctional Composites, Aditya R. Thakur

Doctoral Dissertations

“This study details the research to facilitate fabrication and characterization of novel structural composites reinforced with carbon fibers. Across industries, materials with high performance-to-weight ratio are sought after. Using carbon fibers as secondary phases in these proposed composites, specific characteristics can be tailored in these materials to manufacture strong, lightweight, high performance structures. The first part of the research focused on the improvement in the mechanical properties of the composites using carbon fiber reinforcement. As a part of this study, toughened ceramic composites with predictable failure patterns were produced using carbon fiber inclusions. A closed-form analytical model was developed to …

On Geometric Design Rules And In-Process Build Quality Monitoring Of Thin-Wall Features Made Using Laser Powder Bed Fusion Additive Manufacturing Process, Aniruddha Gaikwad

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The goal of this thesis is to quantify the link between the design features (geometry), in-process signatures, and build quality of parts made using the laser powder bed fusion (LPBF) additive manufacturing (AM) process. This knowledge is the foundational basis for proposing design rules in AM, as well as for detecting the impending build failures using in-process sensor data.

As a step towards this goal, the objectives of this work are two-fold:

1) Quantify the effect of the geometry and orientation on the build quality of thin-wall features. To explain further, the geometry related factor is the ratio of the …

Material Characterization And Fracture Prediction Of Fdm Printed Parts, Sanchita Sheth

Mechanical and Aerospace Engineering Theses - Archive

In order to take advantage of the design freedom that Additive Manufacturing offers, most applications require reliable material characterization. This can ensure that a design performs within its environment and life requirements. This work discusses two models. One investigates the raster angle dependency of stiffness properties and the other numerically predicts fracture in Fused Deposition Modeling (FDM) printed polymer parts. Pre-processing of FDM geometry was done in Abaqus CAE (SIMULIA TM). FEA and post-processing was done in BSAM, which is a damage prediction software developed for composites. BSAM uses a regularized extended finite element approach of Discrete Damage Modeling. In …

Additively Manufactured Continuous Carbon Fiber Thermoplastic Composites For High-Performance Applications, Nekoda Van De Werken

Mechanical Engineering ETDs

The goal of this dissertation is to provide a foundation for the advancement of additive manufacturing (AM) toward production of high-performance carbon fiber reinforced polymer matrix composites (CFRPs). AM can provide valuable advantages over conventional composite manufacturing techniques, including the control over fiber orientation, capability of manufacturing complex geometries, out-of-autoclave processing, elimination of the need for composite tooling, and the ability to perform lights-out manufacturing. Currently, however, a suite of challenges related to modelling, design, manufacturing defects, and general limitations in the current understanding of the processing-structure-property relationships exist in AM of composites. To this end, this dissertation investigates novel …

Open Source Waste Plastic Granulator, Arvind Ravindran, Sean Scsavnicki, Walker Nelson, Peter Gorecki, Jacob Franz, Shane Oberloier, Theresa K. Meyer, Andrew Barnard, Joshua M. Pearce

Michigan Tech Publications, Part 1

In order to accelerate deployment of distributed recycling by providing low-cost feed stocks of granulated post-consumer waste plastic, this study analyzes an open source waste plastic granulator system. It is designed, built, and tested for its ability to convert post-consumer waste, 3D printed products and waste into polymer feedstock for recyclebots of fused particle/granule printers. The technical specifications of the device are quantified in terms of power consumption (380 to 404 W for PET and PLA, respectively) and particle size distribution. The open source device can be fabricated for less than $2000 USD in materials. The experimentally measured power use …

Smart Additive Manufacturing: In-Process Sensing And Data Analytics For Online Defect Detection In Metal Additive Manufacturing Processes, Mohammad Montazeri

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The goal of this dissertation is to detect the incipient flaws in metal parts made using additive manufacturing processes (3D printing). The key idea is to embed sensors inside a 3D printing machine and conclude whether there are defects in the part as it is being built by analyzing the sensor data using artificial intelligence (machine learning). This is an important area of research, because, despite their revolutionary potential, additive manufacturing processes are yet to find wider acceptance in safety-critical industries, such as aerospace and biomedical, given their propensity to form defects. The presence of defects, such as porosity, can …

Adhesion Testing Of Printed Inks While Varying The Surface Treatment Of Polymer Substrates, Clayton Neff, Edwin Elston, Amanda Schrand, Nathan B. Crane

Faculty Publications

Additive manufacturing with conductive materials enables new approaches to printed electronics that are unachievable by standard electronics manufacturing processes. In particular, electronics can be embedded directly into structural components in nearly arbitrary 3D space. While these methods incorporate many of the same materials, the new processing methods require standard test methods to compare materials, processing conditions, and determine design limits. This work demonstrates a test method to quantitatively measure the adhesion failure of printed inks deposited on a substrate without changing the ink printing conditions. The proposed method is an adaption of single lap shear testing in which the lap …

Mechanical And Temperature Resilience Of Multi-Material Systems For Printed Electronics Packaging, Clayton Neff, Justin Nussbaum, Chris Gardiner, Nathan B. Crane, James L. Zunino, Mike Newton

Faculty Publications

In this work, two AM technologies were utilized to compare the effectiveness of fabricating a simple electronic device with a conductive trace and hollow cylinder representative of ‘printed packaging’ that would survive harsh environmental conditions. The printed packaging cylinder delineates printed potting for electronics packaging. An nScrypt direct write (DW) system was the primary manufacturing system but a developing technology—coined large area projection sintering (LAPS)—manufactured a subset of samples for comparison. The tests follow Military Standard (MIL STD) 883K and include resiliency evaluation for die shear strength, temperature cycling, thermal shock, and high G loading by mechanical shock. Results indicate …

Design And Optimization Of Additively Manufactured Heat Sink And Heat Spreader For Microelectronics Cooling, Aditya Krishna Ganesh Ram

Mechanical and Aerospace Engineering Theses - Archive

High performance cooling is a critical requirement for modern microprocessors that generate large amounts of non-uniformly distributed heat. Metal heat spreaders and heat sinks have been traditionally used for thermal management. While the design of these components has traditionallly been restricted by manufacturability, in recent years, additive manufacturing has offered the capability to manufacture almost any design. This work analyzes and optimizes the performance of an additively manufactured heat sink and heat spreader. Computational heat transfer simulations were carried out to understand the variation of chip temperature and pressure drop for various designs. Discussion of key findings include the thermal …

Fabrication And Characterization Of Alₓcrcufeni₂ High-Entropy Alloys Coatings By Laser Metal Deposition, Wenyuan Cui, Xinchang Zhang, Lan Li, Yitao Chen, Tan Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

High-entropy alloys (HEAs) are becoming new hot spots in the metallic materials community, which are defined to contain equiatomic or close-to-equiatomic compositions. HEAs can possess many interesting mechanical properties, and in particular, they have the great potential to be used as coating materials requiring high hardness and wear resistance. In this study, the feasibility of fabrication AlₓCrCuFeNi₂ (x=0,0.75) HEAs was investigated via laser metal deposition from elemental powders. The microstructure, phase structure, and hardness were studied by an optical microscope, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), electron backscatter diffraction (EBSD) and Vickers hardness tester. The bonding between the …

Modeling Thermal And Mechanical Cancellation Of Residual Stress From Hybrid Additive Manufacturing By Laser Peening, Guru Madireddy, Chao Li, Jingfu Liu, Michael P. Sealy

Department of Mechanical and Materials Engineering: Faculty Publications

Additive manufacturing (AM) of metals often results in parts with unfavorable mechanical properties. Laser peening (LP) is a high strain rate mechanical surface treatment that hammers a workpiece and induces favorable mechanical properties. Peening strain hardens a surface and imparts compressive residual stresses improving the mechanical properties of a material. This work investigates the role of LP on layer-by-layer processing of 3D printed metals using finite element analysis. The objective is to understand temporal and spatial residual stress development after thermal and mechanical cancellation caused by cyclically coupling printing and peening. Results indicate layer peening frequency is a critical process …

Micro-Ct Evaluation Of Defects In Ti-6al-4v Parts Fabricated By Metal Additive Manufacturing, Haijun Gong, Venkata Karthik Nadimpalli, Khalid Rafi, Thomas Starr, Brent Stucker

Manufacturing Engineering: Faculty Publications (2015-2023)

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 evaluate inclusion defects in the SLM and EBM specimens is discussed. The porosity of EBM specimens was analyzed through image processing of CT single slices. An empirical method is also proposed to estimate the porosity of reconstructed models of the CT scan.

A Hybrid Process Integrating Reverse Engineering, Pre-Repair Processing, Additive Manufacturing, And Material Testing For Component Remanufacturing, Xinchang Zhang, Wenyuan Cui, Wei Li, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Metallic components can gain defects such as dents, cracks, wear, heat checks, deformation, etc., that need to be repaired before reinserting into service for extending the lifespan of these parts. In this study, a hybrid process was developed to integrate reverse engineering, pre-repair processing, additive manufacturing, and material testing for the purpose of part remanufacturing. Worn components with varied defects were scanned using a 3D scanner to recreate the three-dimensional models. Pre-repair processing methods which include pre-repair machining and heat-treatment were introduced. Strategies for pre-repair machining of defects including surface impact damage, surface superficial damage and cracking were presented. Pre-repair …

Evaluation Of Tensile Properties For Selective Laser Melted 316l Stainless Steel And The Influence Of Inherent Process Features, Paul Swartz

Master's Theses

Optimal print parameters for additively manufacturing 316L stainless steel using selective laser melting (SLM) at Cal Poly had previously been identified. In order to further support the viability of the current settings, tensile material characteristics were needed. Furthermore, reliable performance of the as-printed material had to be demonstrated. Any influence on the static performance of parts in the as-printed condition inherent to the SLM manufacturing process itself needed to be identified. Tensile testing was conducted to determine the properties of material in the as-printed condition. So as to have confidence in the experimental results, other investigations were also conducted to …

Mechanical Properties And Applications Of Recycled Polycarbonate Particle Material Extrusion-Based Additive Manufacturing, Matthew J. Reich, Aubrey Woern, Nagendra Gautam Tanikella, Joshua M. Pearce

Michigan Tech Publications, Part 1

Past work has shown that particle material extrusion (fused particle fabrication (FPF)/fused granular fabrication (FGF)) has the potential for increasing the use of recycled polymers in 3D printing. This study extends this potential to high-performance (high-mechanical-strength and heat-resistant) polymers using polycarbonate (PC). Recycled PC regrind of approximately 25 mm² was 3D printed with an open-source Gigabot X and analyzed. A temperature and nozzle velocity matrix was used to find useful printing parameters, and a print test was used to maximize the output for a two-temperature stage extruder for PC. ASTM type 4 tensile test geometries as well as ASTM-approved …

Characterization Of 3d Printed Pla With The Help Of Mechanical, Di-Electric And X-Ray Diffraction Techniques, Sai Sri Nidhi Munaganuru

Mechanical and Aerospace Engineering Theses - Archive

Additive manufacturing (AM) revolutionized many industries, i.e., Automotive, Biomedical, Aerospace and Defense. As opposed to traditional manufacturing methods, a part is manufactured layer by layer from 3D CAD models in AM. Though the vision of AM is impressive, there are many challenges that are hindering the widespread use of these complex parts. One of the main challenges is its strength that varies with different manufacturing parameters. We are going to investigate the effect of build parameters on the mechanical, electrical and crystalline properties of the additively manufactured heterogeneous material system. The goal of the thesis is to find a correlation …

Open Source Completely 3-D Printable Centrifuge, Salil S. Sule, Aliaksei Petsiuk, Joshua M. Pearce

Michigan Tech Publications, Part 1

Centrifuges are commonly required devices in medical diagnostics facilities as well as scientific laboratories. Although there are commercial and open source centrifuges, the costs of the former and the required electricity to operate the latter limit accessibility in resource-constrained settings. There is a need for low-cost, human-powered, verified, and reliable lab-scale centrifuges. This study provides the designs for a low-cost 100% 3-D printed centrifuge, which can be fabricated on any low-cost RepRap-class (self-replicating rapid prototyper) fused filament fabrication (FFF)- or fused particle fabrication (FPF)-based 3-D printer. In addition, validation procedures are provided using a web camera and free and open …

A Study On Ultrasonic Energy Assisted Metal Processing : Its Correeltion With Microstructure And Properties, And Its Application To Additive Manufacturing., Anagh Deshpande

Electronic Theses and Dissertations

Additive manufacturing or 3d printing is the process of constructing a 3-dimensional object layer-by-layer. This additive approach to manufacturing has enabled fabrication of complex components directly from a computer model (or a CAD model). The process has now matured from its earlier version of being a rapid prototyping tool to a technology that can fabricate service-ready components. Development of low-cost polymer additive manufacturing printers enabled by open source Fused Deposition Modeling (FDM) printers and printers of other technologies like SLA and binder jetting has made polymer additive manufacturing accessible and affordable. But the metal additive manufacturing technologies are still expensive …