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Mechanical and Aerospace Engineering Faculty Research & Creative Works
- Discipline
- Keyword
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- Solid Freeform Fabrication (9)
- Additive manufacturing (8)
- Deposition (7)
- 3D printers (6)
- Rapid Prototyping (6)
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- Binders (5)
- Extrusion (5)
- Laser heating (5)
- Manufacture (5)
- Selective laser sintering (5)
- Additive Manufacturing (4)
- Additives (4)
- Fabrication (4)
- Ice Patterns (4)
- Laser Deposition (4)
- Laser metal deposition (4)
- Mechanical properties (4)
- Rapid Tooling (4)
- Repair (4)
- Sintering (4)
- Bioactive glass (3)
- Ceramic (3)
- Compressive strength (3)
- Investment Casting (3)
- Laser Metal Deposition (3)
- Layered Manufacturing (3)
- Mechanical Properties (3)
- Metallic glass (3)
- Process parameters (3)
- Rapid Freeze Prototyping (3)
Articles 31 - 60 of 190
Full-Text Articles in Manufacturing
Effect Of Environmental Variables On Ti-64 Am Simulation Results, Aaron Flood, Frank W. Liou
Effect Of Environmental Variables On Ti-64 Am Simulation Results, Aaron Flood, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In metal AM the environment is critical and therefore care should be taken to ensure that the simulation matches reality. This paper will investigate the effect that various environmental factors have on the results of the simulation. This will help to determine their importance in the simulation setup. The material properties which relate to this are the convective coefficient and the emissivity. These material properties will be investigated to determine their effect on the outcome of the simulation. In addition to these properties, the size of the substrate will be investigated to determine if any results are altered. Lastly, the …
Characterization Of Impact Toughness Of 304l Stainless Steel Fabricated Through Laser Powder Bed Fusion Process, Sreekar Karnati, Atoosa Khiabhani, Aaron Flood, Frank W. Liou, Joseph William Newkirk
Characterization Of Impact Toughness Of 304l Stainless Steel Fabricated Through Laser Powder Bed Fusion Process, Sreekar Karnati, Atoosa Khiabhani, Aaron Flood, Frank W. Liou, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this research, the impact toughness of powder bed based additively manufactured 304L stainless steel was investigated. Charpy specimens were built in vertical, horizontal and inclined (45⁰) orientations to investigate the variation in toughness with build direction. These specimens were tested in as-built and machined conditions. A significant difference in toughness was observed with varying build directions. The lowest toughness values were recorded when the notch was oriented in line with the interlayer boundary. The highest toughness was recorded when the notch was perpendicular to the interlayer boundary. A significant scatter in toughness values was also observed. The variation and …
Effects Of Identical Parts On A Common Build Plate On The Modal Analysis Of Slm Created Metal, Tristan Cullom, Troy Hartwig, Ben Brown, Kevin Johnson, Jason Blough, Andrew Barnard, Robert G. Landers, Douglas A. Bristow, Edward C. Kinzel
Effects Of Identical Parts On A Common Build Plate On The Modal Analysis Of Slm Created Metal, Tristan Cullom, Troy Hartwig, Ben Brown, Kevin Johnson, Jason Blough, Andrew Barnard, Robert G. Landers, Douglas A. Bristow, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The frequency response of parts created with Additive Manufacturing (AM) is a function of not only process parameters, powder quality, but also the geometry of the part. Modal analysis has the potential to evaluate parts by measuring the frequency response which are a function of the material response as well as the geometry. A Frequency Response Function (FRF) serves as a fingerprint of the part which can be validated against the FRF of a destructively tested part. A practical scenario encountered in Selective Laser Melting (SLM) involves multiple parts on a common build plate. Coupling between parts influences the FRF …
Use Of Swir Imaging To Monitor Layer-To-Layer Part Quality During Slm Of 304l Stainless Steel, Cody S. Lough, Xin Wang, Christopher C. Smith, Olaseni Adeniji, Robert G. Landers, Douglas A. Bristow, Edward C. Kinzel
Use Of Swir Imaging To Monitor Layer-To-Layer Part Quality During Slm Of 304l Stainless Steel, Cody S. Lough, Xin Wang, Christopher C. Smith, Olaseni Adeniji, Robert G. Landers, Douglas A. Bristow, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper evaluates using in-situ SWIR imaging to monitor part quality and identify potential defect locations introduced during Selective Laser Melting (SLM) of 304L stainless steel. The microstructure (porosity, grain size, and phase field) and engineering properties (density, modulus, and yield strength) depend on the thermal history during SLM manufacturing. Tensile test specimens have been built with a Renishaw AM250 using varied processing conditions to generate different thermal histories. SWIR imaging data is processed layer-to-layer to extract features in the thermal history for each process condition. The features in the thermal history are correlated with resulting part engineering properties, microstructure, …
In-Situ Optical Emission Spectroscopy During Slm Of 304l Stainless Steel, Cody S. Lough, Luis I. Escano, Minglei Qu, Christopher C. Smith, Robert G. Landers, Douglas A. Bristow, Lianyi Chen, Edward C. Kinzel
In-Situ Optical Emission Spectroscopy During Slm Of 304l Stainless Steel, Cody S. Lough, Luis I. Escano, Minglei Qu, Christopher C. Smith, Robert G. Landers, Douglas A. Bristow, Lianyi Chen, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper demonstrates the potential of in-situ Optical Emission Spectroscopy (OES) to monitor the Selective Laser Melting (SLM) process. A spectrometer is split into the beam path of a home-built SLM system to collect visible light emitted from the melt pool and plume. The inline configuration allows signal collection regardless of the laser scan location. The spectral data can be used to calculate the temperature of the vapor plume and correlated with the melt-pool size. The effects of varying the atmosphere and pressure on the OES signal are also explored. These results demonstrate that OES can provide useful feedback to …
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
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. …
Modeling Of Cloud-Based Digital Twins For Smart Manufacturing With Mt Connect, Liwen Hu, Ngoc-Tu Nguyen, Wenjin Tao, Ming-Chuan Leu, Xiaoqing Frank Liu, Rakib Shahriar, S M Nahian Al Sunny
Modeling Of Cloud-Based Digital Twins For Smart Manufacturing With Mt Connect, Liwen Hu, Ngoc-Tu Nguyen, Wenjin Tao, Ming-Chuan Leu, Xiaoqing Frank Liu, Rakib Shahriar, S M Nahian Al Sunny
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The common modeling of digital twins uses an information model to describe the physical machines. The integration of digital twins into productive cyber-physical cloud manufacturing (CPCM) systems imposes strong demands such as reducing overhead and saving resources. In this paper, we develop and investigate a new method for building cloud-based digital twins (CBDT), which can be adapted to the CPCM platform. Our method helps reduce computing resources in the information processing center for efficient interactions between human users and physical machines. We introduce a knowledge resource center (KRC) built on a cloud server for information intensive applications. An information model …
Foil-Based Additive Manufacturing System And Method, Hai-Lung Tsai, Yiyu Shen, Yingqi Li, Chen Chen
Foil-Based Additive Manufacturing System And Method, Hai-Lung Tsai, Yiyu Shen, Yingqi Li, Chen Chen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An additive manufacturing system, method of manufacturing, and fabricated part. The system uses a material joining laser system to join together foil sheets to form a metal part. The material joining laser system can be configured to join adjacent foil sheets together in a substantially uniform manner. The manufacturing system also includes a material removal system that removes material from selected locations of the foil sheets to shape the foil sheets to correspond with selective slices of the part. The material removal system can be a laser system, such as a laser system configured to remove material from a foil …
A Two-Dimensional Simulation Of Grain Structure Growth Within Substrate And Fusion Zone During Direct Metal Deposition, Jingwei Zhang, Wei Li, Frank W. Liou, Joseph William Newkirk
A Two-Dimensional Simulation Of Grain Structure Growth Within Substrate And Fusion Zone During Direct Metal Deposition, Jingwei Zhang, Wei Li, Frank W. Liou, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper, a predictive model based on a cellular automaton (CA)-finite element (FE) method has been developed to simulate thermal history and microstructure evolution during metal solidification for a laser-based additive manufacturing process. The macroscopic FE calculation that is validated by thermocouple experiment is designed to update the temperature field and a high cooling rate. A cellular automata-finite element (CAFE) method is developed to describe grain growth in the fusion zone. In the mesoscopic CA model, heterogeneous nucleation sites, grain growth orientation and rate, epitaxial growth, remelting of preexisting grains, metal addition, grain competitive growth, and columnar to equiaxed …
Development Of A Hybrid Manufacturing Process For Precision Metal Parts, Leon Hill, Todd E. Sparks, Frank W. Liou
Development Of A Hybrid Manufacturing Process For Precision Metal Parts, Leon Hill, Todd E. Sparks, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper summarizes the research and development of a hybrid manufacturing process to produce fully dense metal parts with CNC-level precision. High performance metals, such as titanium alloys, nickel superalloys, tool steels, stainless steels, etc. can benefit from this process. Coupling the additive and the subtractive processes into a multi-axis workstation, the hybrid process, can produce and repair metal parts with accuracy. The surface quality of the final product is similar to the industrial milling capability. To achieve such a system, issues of the metal deposition process and the automated process planning of the hybrid manufacturing process will be discussed.
Review Of Am Simulation Validation Techniques, Aaron Flood, Frank W. Liou
Review Of Am Simulation Validation Techniques, Aaron Flood, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Due to the complexity of Additive Manufacturing (AM), it can require many trial runs to obtain processing parameters which produce a quality build. Because of this trial and error process, the drive for simulations of AM has grown significantly. Simulations only become useful to researchers if it can be shown that they are true representations of the physical process being simulated. All simulations have different methods of validation to show that they are an accurate representations of the process. This paper explores the various methodologies for validation of laser based metal AM simulations, focusing mainly on the modeling of the …
Towards Defect Detection In Metal Slm Parts Using Modal Analysis "Fingerprinting", James Urban, Nick E. Capps, Brian M. West, Troy Hartwig, Ben Brown, Robert G. Landers, Douglas A. Bristow, Edward C. Kinzel
Towards Defect Detection In Metal Slm Parts Using Modal Analysis "Fingerprinting", James Urban, Nick E. Capps, Brian M. West, Troy Hartwig, Ben Brown, Robert G. Landers, Douglas A. Bristow, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The validation of Additively Manufactured (AM) materials is a difficult and expensive process because the local engineering properties are a function of the thermal history. The thermal history varies with the process parameters, as well as the part geometry. This paper presents a case study using modal testing to identify defects in realistic AM parts. A setup consisting of a Scanning Laser Doppler Vibrometer (LDV) was used to identify the resonant frequencies for several geometrically identical parts on a build plate. Parts with suboptimal process parameters from purposely varying the process parameters, are identified by a shift in the mode …
Metallic Components Repair Strategies Using The Hybrid Manufacturing Process, Xinchang Zhang, Wenyuan Cui, Wei Li, Frank W. Liou
Metallic Components Repair Strategies Using The Hybrid Manufacturing Process, Xinchang Zhang, Wenyuan Cui, Wei Li, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The hybrid manufacturing process which integrates additive manufacturing with subtractive machining is competitive and promising in component repair. To automate this process, detecting the missing volume and generating the deposition tracks is the key. In this study, strategies for repairing defects on flat and non-flat surfaces were investigated. A cost-effective reverse engineering tool was utilized to reconstruct STL models of damaged objects. Point data of the fracture surface on flat surfaces was obtained to generate the tool path for material building up. For defects on non-flat surfaces, the damaged model was best-fitted with the nominal model. Then both models were …
Fabricating Zirconia Parts With Organic Support Material By The Ceramic On-Demand Extrusion Process, Wenbin Li, Amir Ghazanfari, Devin Mcmillen, Andrew Scherff, Ming-Chuan Leu, Greg Hilmas
Fabricating Zirconia Parts With Organic Support Material By The Ceramic On-Demand Extrusion Process, Wenbin Li, Amir Ghazanfari, Devin Mcmillen, Andrew Scherff, Ming-Chuan Leu, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Ceramic On-Demand Extrusion (CODE) is an extrusion-based additive manufacturing process recently developed for fabricating dense, functional ceramic components. This paper presents a further development of this process and focuses on fabricating 3 mol% yttria-stabilized zirconia (3YSZ) components that cannot be fabricated without using support structures. The 3YSZ paste is deposited through the main nozzle, and a polycaprolactone (PCL) pellet feedstock is melted and deposited through an auxiliary nozzle to build support structures. After a green part is printed and dried, the support structures are removed by heating the part to ~70 ⁰C to melt the PCL. The part is then …
Construction Of Metallic Glass Structures By Laser-Foil-Printing Technology, Yiyu Shen, Yingqi Li, Hai-Lung Tsai
Construction Of Metallic Glass Structures By Laser-Foil-Printing Technology, Yiyu Shen, Yingqi Li, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Metallic glasses (MGs) have superior mechanical properties such as high tensile strength, hardness, and corrosion resistance, as compared to crystalline metals. Although newly developed MGs have significantly reduced critical cooling rates down to 10 K/s, products of MGs are still limited to simple geometries such as foils/plates or rods with thin section-thickness which is mainly caused by the decrease of thermal conductivities of the new MGs. Recently, we developed a new Laser-foil-printing (LFP) additive manufacturing technology which welds foils, layer by layer, to construct desired 3D structures. With the LFP and Zr-based amorphous foils, 3D, large amorphous structures with complex …
Defects Classification Of Laser Metal Deposition Using Acoustic Emission Sensor, Haythem Gaja, Frank W. Liou
Defects Classification Of Laser Metal Deposition Using Acoustic Emission Sensor, Haythem Gaja, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Laser metal deposition (LMD) is an advanced additive manufacturing (AM) process used to build or repair metal parts layer by layer for a range of different applications. Any presence of deposition defects in the part produced causes change in the mechanical properties and might cause failure to the part. In this work, defects monitoring system was proposed to detect and classify defects in real time using an acoustic emission (AE) sensor and an unsupervised pattern recognition analysis. Time domain and frequency domain, and relevant descriptors were used in the classification process to improve the characterization and the discrimination of the …
Characterization Of Heat-Affected Powder Generated During Selective Laser Melting Of 304l Stainless Steel Powder, Austin T. Sutton, Caitlin S. Kriewall, Ming-Chuan Leu, Joseph William Newkirk
Characterization Of Heat-Affected Powder Generated During Selective Laser Melting Of 304l Stainless Steel Powder, Austin T. Sutton, Caitlin S. Kriewall, Ming-Chuan Leu, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The selective laser melting (SLM) process is an Additive Manufacturing (AM) technique that uses a laser to fuse successive layers of powder into near fully dense components. Due to the large energy input from the laser during processing, vaporization and instabilities in the melt pool occur causing the formation of condensate and laser spatter, collectively known as heat-affected powder. Since heat-affected powder settles into the powder bed, the properties of the unconsolidated powder may be altered compromising its reusability. In this study, characterization of 304L heat-affected powder was performed through particle size distribution measurements, x-ray diffraction, metallography, energy-dispersive spectroscopy mapping, …
Influence Of Gage Length On Miniature Tensile Characterization Of Powder Bed Fabricated 304l Stainless Steel, Sreekar Karnati, Jack L. Hoerchler, Frank W. Liou, Joseph William Newkirk
Influence Of Gage Length On Miniature Tensile Characterization Of Powder Bed Fabricated 304l Stainless Steel, Sreekar Karnati, Jack L. Hoerchler, Frank W. Liou, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Miniature tensile specimens with varying aspect ratios were fabricated from 304L stainless steel (SS) made using powder bed additive manufacturing (AM) process. The tensile characteristics measured from these specimens were analyzed to assess the impact of gage length. The study found no impact upon varying gage length on yield and ultimate strength measurements. However, a significant impact was observed on strain measurements. This data was also used to perform Weibull statistics to estimate the stochastic performance of the material. Fractography was performed to visually identify the types of flaws. A comparative study with specimens fabricated from cold rolled annealed 304 …
Investigation Of Build Strategies For A Hybrid Manufacturing Process Progress On Ti-6al-4v, Lei Yan, Leon Hill, Frank W. Liou, Joseph William Newkirk
Investigation Of Build Strategies For A Hybrid Manufacturing Process Progress On Ti-6al-4v, Lei Yan, Leon Hill, Frank W. Liou, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The various processing parameters of a hybrid manufacturing process, including deposition and machining, is being investigated with a Design of Experiment (DoE). The intent was to explore the effect of different build strategies on the final part’s Vickers hardness, tensile test, fatigue life, and microstructure. From this experiment, the processing parameters can be linked to various mechanical properties. This will lead to the ability to create a combination of deposition and machining parameters, which will result in improved mechanical properties.
Bonding Of 304l Stainless Steel To Cast Iron By Selective Laser Melting, Baily Thomas, Austin T. Sutton, Ming-Chuan Leu, Nikhil Doiphode
Bonding Of 304l Stainless Steel To Cast Iron By Selective Laser Melting, Baily Thomas, Austin T. Sutton, Ming-Chuan Leu, Nikhil Doiphode
Mechanical and Aerospace Engineering Faculty Research & Creative Works
While cast iron is widely used in industry, a major limitation is the weldability of a dissimilar material onto cast iron due to hot cracking as a result of lack of ductility from graphite flakes. Consequently, a significant amount of preheat is often employed to reduce the cooling rate in the fusion zone, which, however, may lead to distortion of the welded parts. A potential remedy could be the Selective Laser Melting (SLM) process, where only small melt pools are created and thus the overall energy input is reduced. The present paper describes an investigation of the SLM process to …
Building Zr-Based Metallic Glass Part On Ti-6al-4v Substrate By Laser-Foil-Printing Additive Manufacturing, Yingqi Li, Yiyu Shen, Ming-Chuan Leu, Hai-Lung Tsai
Building Zr-Based Metallic Glass Part On Ti-6al-4v Substrate By Laser-Foil-Printing Additive Manufacturing, Yingqi Li, Yiyu Shen, Ming-Chuan Leu, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Through using Zr intermediate layers, Zr52.5Ti5Al10Ni14.6Cu17.9 metallic glass (MG) parts are successfully built on Ti-6Al-4V substrates by laser-foil-printing (LFP) additive manufacturing technology in which MG foils are laser welded layer-by-layer onto the substrate. The printed MG part is free of porosity, cracking and crystallization; additionally, its glass transition temperature, crystallization temperature, micro-hardness, and tensile strength are very similar to the original MG material. The Zr intermediate layers are aimed at preventing direct interaction between the first layer of MG foil and the Ti substrate; otherwise, the welded MG foils would peel …
Fabricating Zirconia Components With Organic Support Material By The Ceramic On-Demand Extrusion Process, Wenbin Li, Amir Ghazanfari, Devin Mcmillen, Andrew Scherff, Ming-Chuan Leu, Greg Hilmas
Fabricating Zirconia Components With Organic Support Material By The Ceramic On-Demand Extrusion Process, Wenbin Li, Amir Ghazanfari, Devin Mcmillen, Andrew Scherff, Ming-Chuan Leu, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Ceramic On-Demand Extrusion (CODE) is an extrusion-based additive manufacturing process recently developed for fabricating dense, functional ceramic components. This paper presents a further development of this process and focuses on fabricating 3 mol% yttria-stabilized zirconia (3YSZ) components that cannot be fabricated without using support structures. The 3YSZ paste is deposited through the main nozzle, and a polycaprolactone (PCL) pellet feedstock is melted and deposited through an auxiliary nozzle to build support structures. After a green part is printed and dried, the support structures are removed by heating the part to ~70°C to melt the PCL. The part is then sintered …
Mechanical Properties Of 304l Parts Made By Laser-Foil-Printing Technology, Chia-Hung Hung, Yiyu Shen, Ming-Chuan Leu, Hai-Lung Tsai
Mechanical Properties Of 304l Parts Made By Laser-Foil-Printing Technology, Chia-Hung Hung, Yiyu Shen, Ming-Chuan Leu, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Laser-Foil-Printing (LFP) is a novel laminated object manufacturing process for metal additive manufacturing. It fabricates three-dimensional metal parts by using a dual-laser system to weld and cut metal foils layer by layer. A main advantage of LFP is the higher cooling rate compared to powder-based laser additive manufacturing processes due to the thermal conductivity difference between foil and powder. This study focuses on the mechanical properties of 304L stainless steel parts built by the LFP process. The experimental results indicate that the yield strength and ultimate tensile strength of LFP fabricated 304L SS parts are higher by 9% and 8% …
Additive Manufacturing Of High Entropy Alloys -- A Review, Wenyuan Cui, Xinchang Zhang, Frank W. Liou
Additive Manufacturing Of High Entropy Alloys -- A Review, Wenyuan Cui, Xinchang Zhang, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
High-entropy alloys have attracted increasingly interest due to their unique compositions, microstructures and mechanical properties. Additive manufacturing has been recognized as a promising technology to fabricate the high-entropy alloys in the recent years. The purpose of this paper is to review the current research progress in high-entropy alloys by additive manufacturing process. It will first highlight the important theory of the high-entropy alloys. The next aspect is to summarize current additive manufacturing methods applied for the high entropy alloys. At last, the correlation between the microstructures and the mechanical properties of the high-entropy alloys will be examined and discussed.
Fiber-Fed Laser-Heated Process For Printing Transparent Glass, John M. Hostetler, Jonathan T. Goldstein, Douglas A. Bristow, Robert G. Landers, Edward C. Kinzel
Fiber-Fed Laser-Heated Process For Printing Transparent Glass, John M. Hostetler, Jonathan T. Goldstein, Douglas A. Bristow, Robert G. Landers, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper presents the Additive Manufacturing (AM) of glass using a fiber-fed process. Glass fiber with a diameter of 100 μm is fed into a laser generated melt pool. A CO2 laser beam is focused on the intersection between the fiber and the work piece which is positioned on a four-axis computer controlled stage. The laser energy at λ=10.6 μm is directly absorbed by the silica and locally heats the glass above the working point. By carefully controlling the laser power, scan speed, and feed rate, bubble free shapes can be deposited including trusses and basic lenses. Issues unique …
Effect Of Optimizing Particle Size In Laser Metal Deposition With Blown Pre-Mixed Powders, Wei Li, Jingwei Zhang, Xinchang Zhang, Sreekar Karnati, Frank W. Liou
Effect Of Optimizing Particle Size In Laser Metal Deposition With Blown Pre-Mixed Powders, Wei Li, Jingwei Zhang, Xinchang Zhang, Sreekar Karnati, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Functionally Graded Material (FGM) is often fabricated by Laser metal deposition with pre-mixed multiple powders (PMM-powder). Since the supplied PMM-powder directly affects FGM’s composition, investigation on PMM-powder’s property is greatly needed. This paper employed experimental method to observe an important problem: PMM-powder separation in fabricating FGM. A novel particle size optimization method was introduced as solution to eliminate the powder separation. Pre-mixed pure Cu and 4047 Al powders were used to do two experiments. The first experiment result disclosed the existence of powder separation. By optimizing the particle size, the PMM-powder separation was effectively solved in the second experiment result.
Relating Processing Of Selective Laser Melted Structures To Their Material And Modal Properties, Nicholas E. Capps, James S. Urban, Brian M. West, Cody S. Lough, Adriane Repogle, Troy Hartwig, Ben Brown, Douglas A. Bristow, Robert G. Landers, Edward C. Kinzel
Relating Processing Of Selective Laser Melted Structures To Their Material And Modal Properties, Nicholas E. Capps, James S. Urban, Brian M. West, Cody S. Lough, Adriane Repogle, Troy Hartwig, Ben Brown, Douglas A. Bristow, Robert G. Landers, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Selective Laser Melting (SLM) creates metal parts by fusing powder layer-by-layer. It provides significant design flexibility and the possibility of low-volume production. The engineering properties of the printed metal are a function of the local thermal history. This creates challenges for validating Additively Manufactured (AM) parts. This paper correlates the engineering properties (density, modulus, yield strength and ultimate strength) for tensile test specimens created with different process parameters with the resonant frequencies determined using modal testing. The paper shows that yield and ultimate strengths for these specimens can be determined using modal analysis.
Thermal Modeling Of 304l Stainless Steel Selective Laser Melting, Lan Li, Cody S. Lough, Adriane Repogle, Douglas A. Bristow, Robert G. Landers, Edward C. Kinzel
Thermal Modeling Of 304l Stainless Steel Selective Laser Melting, Lan Li, Cody S. Lough, Adriane Repogle, Douglas A. Bristow, Robert G. Landers, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper describes the continuum thermal modeling of the Selective Laser Melting (SLM) process for 304L stainless steel using Abaqus. Temperature dependent thermal properties are obtained from literature and incorporated into the model capturing the change from powder to fully dense stainless steel. The thermal model predicts the temperature history for multi-track scans under different process parameters (laser power, effective scanning speed, hatch spacing) which is used to extract the melt-pool size, solidification rate, and temperature gradients. These are compared to experimental results obtained from a Renishaw AM250 in terms of the melt pool size, grain structure, and cell spacing. …
Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Greg Hilmas
Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An extrusion-based additive manufacturing process, called the Ceramic On-Demand Extrusion (CODE) process, for producing three-dimensional ceramic components with near theoretical density is introduced in this paper. In this process, an aqueous paste of ceramic particles with a very low binder content (< 1 vol%) is extruded through a moving nozzle at room temperature. After a layer is deposited, it is surrounded by oil (to a level just below the top surface of most recent layer) to preclude non-uniform evaporation from the sides. Infrared radiation is then used to partially, and uniformly, dry the just-deposited layer so that the yield stress of the paste increases and the part maintains its shape. The same procedure is repeated for every layer until part fabrication is completed. Several sample parts for various applications were produced using this process and their properties were obtained. The results indicate that the proposed method enables fabrication of large, dense ceramic parts with complex geometries.
Bubble Formation In Additive Manufacturing Of Borosilicate Glass, Junjie Luo, Theresa Bender, Douglas A. Bristow, Robert G. Landers, Jonathan T. Goldstein, Augustine M. Urbas, Edward C. Kinzel
Bubble Formation In Additive Manufacturing Of Borosilicate Glass, Junjie Luo, Theresa Bender, Douglas A. Bristow, Robert G. Landers, Jonathan T. Goldstein, Augustine M. Urbas, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Entrapped bubbles are an important problem in conventional glass manufacturing. It is also a significant factor determining the quality of glass products produced using additive manufacturing (AM). This paper reports on the bubble formation and entrapment in filament-fed AM printing of borosilicate glass. This process involves maintaining a local molten region using a CO2 laser. A 2 mm filament is fed continuously into the molten region while CNC stages position the workpiece relative to the laser and filament feed. Two different bubble regimes are identified in experiments with borosilicate glass. These regimes can be related to different physical phenomena, …