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Missouri University of Science and Technology

2015

Manufacturing

Articles 1 - 20 of 20

Full-Text Articles in Mechanical Engineering

Performance Metric For Powder Feeder Systems In Additive Manufacturing, Venkata Sivaram Bitragunta, Todd E. Sparks, Frank W. Liou Aug 2015

Performance Metric For Powder Feeder Systems In Additive Manufacturing, Venkata Sivaram Bitragunta, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In blown powder Direct Metal Deposition (DMD) process, parts are built by adding metal powder on the melt pool created by the laser system. At low feed rates powder feeder systems have perturbations. The study focused on relationship between the perturbation frequencies by inherent powder feeder designs and its impact on deposition quality. Performance metric determine the relation between perturbations in the powder flow and quality of the deposit. To determine performance metric, various powder feeder designs were analyzed. Perturbation frequencies were introduced to the disk feeder design. The quality of the deposit was determined by the surface roughness of …

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Microstructure And Property Of Tib-Reinforced Ti Alloy Composites By Laser Metal Deposition, Yunlu Zhang, Jingwei Zhang, Frank W. Liou, Joseph William Newkirk Aug 2015

Microstructure And Property Of Tib-Reinforced Ti Alloy Composites By Laser Metal Deposition, Yunlu Zhang, Jingwei Zhang, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

TiB-reinforced Ti alloy composites have been laser deposited with pre-alloyed Ti-6Al4V-1B powder. The microstructure of the as-deposited and heat treated composites have been characterized in detail using scanning electron microscope (SEM). A homogeneous dispersion of needle-like TiB precipitates is formed in the Ti-6Al-4V α/β matrix. TiB precipitates promote formation of small near equaxed α/β grain after β annealing process. The micro-hardness of the laser deposited composites increase 20-30% with 5 vol. % TiB precipitates compared to unreinforced Ti-6Al-4V deposits.

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Depth Of Cut Monitoring For Hybrid Manufacturing Using Acoustic Emission Sensor, Haythem Gaja, Frank W. Liou Aug 2015

Depth Of Cut Monitoring For Hybrid Manufacturing Using Acoustic Emission Sensor, Haythem Gaja, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser Metal Deposition LMD is a hybrid manufacturing process consist of a laser deposition system combined with a 5-axis CNC milling system. During laser deposition many parameters and their interaction affect the dimensional accuracy of the part produced, powder flow rate, laser power and travel speed are some of these parameters. Sensing the acoustic emission during milling marching gives feedback information regarding depth of metal being cut subsequent part dimensions, if an error in dimensions is found certain actions, such as remaching, close loop control, or laser remelting can be carried out to correct it. Thus a reliable hybrid manufacturing …

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Parameter Determination And Experimental Validation Of A Wire Feed Additive Manufacturing Model, Kannan Suresh Kumar, Todd E. Sparks, Frank W. Liou Aug 2015

Parameter Determination And Experimental Validation Of A Wire Feed Additive Manufacturing Model, Kannan Suresh Kumar, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser metal deposition with wire feed is one of the additive manufacturing methods with great scope and robustness. Process parameters plays an important role in controlling the process and obtaining an ideal manufactured part. Simulations tools are highly essential in determining the ideal parameters and melt pool conditions. The current work is a transient 3D model of wire feed additive manufacturing which realizes the heat transfer and fluid flow behavior of the process with varying laser power and power density. The model was programmed in Python and a 1 KW Gaussian beam fiber laser was used to conduct experiments. The …

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Freeform Extrusion Fabrication Of Titanium Fiber Reinforced Bioactive Glass Scaffolds, Albin Thomas, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas Aug 2015

Freeform Extrusion Fabrication Of Titanium Fiber Reinforced Bioactive Glass Scaffolds, Albin Thomas, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Although implants made with bioactive glass have shown promising results for bone repair, their application in repairing load-bearing long bones is limited due to their low fracture toughness and fairly fast degradation response in vivo. In this paper, we describe our investigation of freeform extrusion fabrication of silicate based 13-93 bioactive glass scaffolds reinforced with titanium fibers. A composite paste was prepared with 13-93 bioactive glass filled with titanium fibers (~16 µm in diameter and aspect ratio of ~250) having a volume fraction of 0.4 vol. %. This paste was then extruded to fabricate scaffolds with an extrudate diameter …

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Planning Freeform Extrusion Fabrication Processes With Consideration Of Horizontal Staircase Effect, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Robert G. Landers Aug 2015

Planning Freeform Extrusion Fabrication Processes With Consideration Of Horizontal Staircase Effect, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An algorithm has been developed to estimate the “horizontal” staircase effect and a technique is proposed to reduce this type of geometrical error for freeform extrusion fabrication processes of 3D “solid” parts. The adaptive rastering technique, proposed in this paper, analyzes the geometry of each layer and changes the width of each line of the raster adaptively in order to reduce the staircase error and increase the productivity simultaneously. For each line, the maximum width that results in a staircase error smaller than a predefined threshold is determined for decreasing the fabrication time or increasing the dimensional accuracy, or both. …

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Direct Laser Deposition Of Ti-6al-4v From Elemental Powder Blends, Lei Yan, Xueyang Chen, Wei Li, Frank W. Liou, Joseph William Newkirk Aug 2015

Direct Laser Deposition Of Ti-6al-4v From Elemental Powder Blends, Lei Yan, Xueyang Chen, Wei Li, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A thin-wall structure composed of Ti-6Al-4V has been deposited using direct laser deposition (DLD) from blended Ti, Al, and V elemental powders. The microstructure and composition distribution along the build height direction were intensively investigated using optical microscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), and Vickers hardness testing. The microstructures of the as-deposited Ti-xAl-yV were studied using EDS to determine appropriate weight percentage for Al and V in the blended powders before mixing. The effects of laser power and laser transverse speed on the microstructure were investigated and optimized laser processing parameters were concluded.

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Modeling Of Powder Bed Processing -- A Review, Aaron Flood, Frank W. Liou Aug 2015

Modeling Of Powder Bed Processing -- A Review, Aaron Flood, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Many models have been developed to model powder beds and these methods can be implemented to model a powder bed for Selective Laser Sintering, Selective Laser Melting and any other technique of additive manufacturing which uses powder beds. Two of the main systems are the Discrete Element Method (DEM) and the Geometric Method. The purpose of this paper is to analyze each of the methods. It will first highlight how each of the models creates the powder bed. The next aspect reviewed is the computational time and its causes. And lastly, each of the methods will be examined for their …

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Solid Freeform Fabrication Of Transparent Fused Quartz Using A Filament Fed Process, J. Luo, L. J. Gilbert, C. Qu, B. Morrow, Douglas A. Bristow, Robert G. Landers, J. Goldstein, A. Urbas, Edward C. Kinzel Aug 2015

Solid Freeform Fabrication Of Transparent Fused Quartz Using A Filament Fed Process, J. Luo, L. J. Gilbert, C. Qu, B. Morrow, Douglas A. Bristow, Robert G. Landers, J. Goldstein, A. Urbas, Edward C. Kinzel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Glass is a critical material for many scientific and engineering applications including optics, communications, electronics, and hermetic seals. Despite this technological relevance, there has been minimal research toward Additive Manufacturing (AM) of glass, particularly optically transparent glass. Additive Manufacturing of transparent glass offers potential advantages for lower processing costs for small production volumes, increased design freedom, and the ability to locally vary the optical properties of the part. Compared to common soda lime glass, fused quartz is better for AM since it has lower thermal expansion and higher index homogeneity. This paper presents a study of additive manufacturing of transparent …

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Dc-Gain Layer-To-Layer Stability Criterion In Laser Metal Deposition Processes, Patrick M. Sammons, Douglas A. Bristow, Robert G. Landers Aug 2015

Dc-Gain Layer-To-Layer Stability Criterion In Laser Metal Deposition Processes, Patrick M. Sammons, Douglas A. Bristow, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In Laser Metal Deposition (LMD), a blown powder metal additive manufacturing process, functional metal parts are fabricated in a layer-by-layer fashion. In addition to the in-layer dynamics, which describe how the process evolves within a given layer, the additive-fabrication property of LMD creates a second set of dynamics which describe how the process evolves from layer-to-layer. While these dynamics, termed layer-to-layer dynamics, are coupled with both the in-layer dynamics and the process operating conditions, they are not widely considered in the modeling, process planning, or process control of LMD operations. Because of this, seemingly valid choices for process parameters can …

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Methods Of Extrusion On Demand For High Solids Loading Ceramic Paste In Freeform Extrusion Fabrication, Wenbin Li, Amir Ghazanfari, Ming-Chuan Leu, Robert G. Landers Aug 2015

Methods Of Extrusion On Demand For High Solids Loading Ceramic Paste In Freeform Extrusion Fabrication, Wenbin Li, Amir Ghazanfari, Ming-Chuan Leu, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Fabrication of highly dense parts with complex geometry by paste-extrusion-based solid freeform fabrication processes requires a precise control of the extrusion flow rate to dispense material on demand, which is often referred as Extrusion-On-Demand (EOD). The extrusion process for aqueous ceramic pastes is complex and difficult to control due to their non-Newtonian behavior, compressibility and inhomogeneity. In this study, three methods of EOD (based on ram extruder, needle valve, and auger valve) are introduced and investigated for the extrusion of high solids loading (i.e., > 50%, volumetric) aqueous alumina paste. Optimal extrusion process parameters for these methods are determined through printing …

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Effects Of Temperature On Aqueous Freeform Extrusion Fabrication, Jie Li, Ming-Chuan Leu, Greg Hilmas Aug 2015

Effects Of Temperature On Aqueous Freeform Extrusion Fabrication, Jie Li, Ming-Chuan Leu, Greg Hilmas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An experimental study was conducted to investigate the effect of temperature on ceramic parts produced by paste extrusion based additive manufacturing followed by sintering. A computer-controlled gantry system equipped with a piston extruder was used to extrude aqueous alumina paste. The system includes a temperature control subsystem that allows for freeform extrusion fabrication inside a low-temperature (<0°C) chamber. It can also be used for fabricating parts on a hot plate at ambient or higher temperatures (≥20°C). Test specimens were fabricated from aqueous aluminum pastes at -20°C in the low-temperature chamber and also on the hot plate at 40°C. The minimum angles achievable by these two processes for part fabrication, without use of support material, were compared. Also compared were the relative density and mechanical properties of the parts obtained after sintering. Microstructures were examined via scanning electron microscopy in order to obtain a deeper understanding of the effect of fabrication temperature.

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A Microstructure And Hardness Study Of Functionally Graded Materials Ti6al4v/Tic By Laser Metal Deposition, Jingwei Zhang, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer Aug 2015

A Microstructure And Hardness Study Of Functionally Graded Materials Ti6al4v/Tic By Laser Metal Deposition, Jingwei Zhang, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer

Materials Science and Engineering Faculty Research & Creative Works

Crack free functionally graded material (FGM) Ti6Al4V-TiC has been fabricated by laser metal deposition (LMD) using TiC and Ti6Al4V powder which were premixed for different ratios. This study focuses on the influence of laser processing parameters and TiC compositional distribution on microstructure, Vickers hardness and phase. The microstructure is analyzed by scanning electron microscopy (SEM), x-ray diffraction (XRD) and hardness tests. Primary carbide, eutectic carbide and unmelted carbide are found in the deposit area. When laser power increased, the primary and secondary dendrite arm spacing increased. The laser power and scanning speed did not influence the Vickers hardness distribution significantly.

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Optimal Rastering Orientation In Freeform Extrusion Fabrication Processes, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Robert G. Landers Aug 2015

Optimal Rastering Orientation In Freeform Extrusion Fabrication Processes, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Many researchers have tried to optimize the build direction of additively manufactured parts to minimize the vertical staircase effect. However, the horizontal staircase effect should also be considered when fully dense parts are to be fabricated. In this paper, part inaccuracy due to the horizontal staircase effect is considered in order to determine the optimal rastering orientation in building the part. An algorithm is developed to estimate this inaccuracy and a technique is proposed to minimize it. The effect of rastering orientation on staircase errors is examined, and the particle swarm optimization method is used to determine the optimum rastering …

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A Framework For Large Scale Fused Pellet Modeling (Fpm) By An Industry Robot, Zhiyuan Wang, Renwei Liu, Todd E. Sparks, Frank W. Liou Aug 2015

A Framework For Large Scale Fused Pellet Modeling (Fpm) By An Industry Robot, Zhiyuan Wang, Renwei Liu, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Fused pellet modeling (FPM) is an important method in additive manufacturing technology, where granular material is used instead of filaments. In FPM, prototypes are constructed by the sequential deposition of material layers. As the size of the part increases, the problem of long build times and part deformation becomes critical. In this paper, methods for eliminating the void density during deposition and accuracy control principles for large scale FPM processes are studied. By analyzing the ab initio principles of this process, a mini extruder with variable pitch and progressive diameter screw for the large scale fused deposition is proposed. Based …

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Laser Metal Deposition Of Functionally Gradient Materials From Elemental Copper And Nickel Powders, Sreekar Karnati, Todd E. Sparks, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer Aug 2015

Laser Metal Deposition Of Functionally Gradient Materials From Elemental Copper And Nickel Powders, Sreekar Karnati, Todd E. Sparks, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work deals with the planning and fabrication of a functionally gradient copper-nickel composition via Laser Metal Deposition (LMD). Various compositions of copper and nickel were made by blending different weight percentages which were then sequentially deposited to fabricate functionally gradient copper-nickel thin-wall structures. Analyses were performed by sectioning the thin-wall samples for metallographic, hardness, X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS) studies. The fabrication was studied for identifying and corroborating the deposited compositions and their corresponding gradients. XRD analyses were performed to identify the crystal structure of the deposit. EDS analysis was instrumental in identifying the variation …

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Thermographic Investigation Of Laser Metal Deposition, Sreekar Karnati Jan 2015

Thermographic Investigation Of Laser Metal Deposition, Sreekar Karnati

Masters Theses

"Laser metal deposition as an additive manufacturing technique has been proven to possess the capability for fabricating complex, intricate geometries and excellent material properties through material deposition. Accurate manufacture of such geometric features would require precise control over the material deposition process. The need of the hour are process monitoring and analyses mechanisms that are crucial in ascertaining the occurrence of the intended actions during deposition while also serving as effective learning tools. The current work involved developing and incorporating an Infra-Red (IR) camera as a process monitoring tool for laser metal deposition. Using the IR camera the thermal dynamics …

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Laser Surface And Sub-Surface Repair During Metal Additive Manufacturing, Prudvi Teja Ravi Jan 2015

Laser Surface And Sub-Surface Repair During Metal Additive Manufacturing, Prudvi Teja Ravi

Masters Theses

"This study examines the use of laser surface treatment to repair surface and subsurface defects. Numerical analysis was performed on laser surface melting using Gaussian heat distribution equations to analyze the depth of the melt pool created by the phenomena. Concurrently, a process map was developed with a planned set of experiments by varying the ranges of laser power and travel speed to determine the dimensions of the melt pool across the gamut. The data generated from both the process studies and the numerical analysis was then used to determine the ideal operating ranges of the process parameters to repair …

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Performance Metrics For Powder Feeder Systems In Additive Manufacturing, Venkata Sivaram Bitragunta Jan 2015

Performance Metrics For Powder Feeder Systems In Additive Manufacturing, Venkata Sivaram Bitragunta

Masters Theses

"In blown powder Direct Metal Deposition (DMD) process, parts are built by adding metal powder on the melt pool created by the laser system. At low feed rates powder feeder systems have perturbations. The study focused on relationship between the perturbation frequencies by inherent powder feeder designs and its impact on deposition quality. Performance metric determine the relation between perturbations in the powder flow and quality of the deposit. To determine performance metric, various powder feeder designs were analyzed. Perturbation frequencies were introduced to the disk feeder design. The quality of the deposit was determined by the surface roughness of …

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Parameter Determination And Experimental Validation Of A Wire Feed Additive Manufacturing Model, Kannan Suresh Kumar Jan 2015

Parameter Determination And Experimental Validation Of A Wire Feed Additive Manufacturing Model, Kannan Suresh Kumar

Masters Theses

“Laser metal deposition is an additive manufacturing method with great scope and robustness. The wire fed additive manufacturing method has great opportunities in space applications and other zero gravity manufacturing processes. Process parameters play an important role in controlling the complex phenomenon and obtaining an ideal manufactured part. These parameters can be efficiently determined using simulation tools which are highly essential in visualizing real world experiments, therefore saving time and experimental costs. The objective of this study is to develop a transient 3D model of laser aided wire feed metal deposition which realizes the heat transfer and fluid flow behavior …

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