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Mechanical and Aerospace Engineering Faculty Research & Creative Works

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Full-Text Articles in Manufacturing

Evaluation Of Direct Diode Laser Deposited Stainless Steel 316l On 4340 Steel Substrate For Aircraft Landing Gear Application, Tian Fu, Todd E. Sparks, Frank W. Liou, Joseph William Newkirk, Zhiqiang Fan, Syamala Rani Pulugurtha, Jianzhong Ruan, Hsin-Nan Chou Aug 2009

Evaluation Of Direct Diode Laser Deposited Stainless Steel 316l On 4340 Steel Substrate For Aircraft Landing Gear Application, Tian Fu, Todd E. Sparks, Frank W. Liou, Joseph William Newkirk, Zhiqiang Fan, Syamala Rani Pulugurtha, Jianzhong Ruan, Hsin-Nan Chou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

300M steel is used extensively for aircraft landing gears because of its high strength, ductility and toughness. However, like other high-strength steels, 300M steel is vulnerable to corrosion fatigue and stress corrosion cracking, which can lead to catastrophic consequences in the landing gear. Stainless steels offer a combination of corrosion, wear, and fatigue properties. But for an aircraft landing gear application a higher surface hardness is required. A laser cladding process with fast heating and cooling rates can improve the surface hardness. AISI 4340 steel is used as a lower cost alternative to 300M due to its similar composition. In …

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Freeform Fabrication Of Zirconium Diboride Parts Using Selective Laser Sintering, Ming-Chuan Leu, Erik B. Adamek, Tieshu Huang, Greg Hilmas, Fatih Dogan Aug 2008

Freeform Fabrication Of Zirconium Diboride Parts Using Selective Laser Sintering, Ming-Chuan Leu, Erik B. Adamek, Tieshu Huang, Greg Hilmas, Fatih Dogan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using the Selective Laser Sintering (SLS) process, both flexural test bars and 3D fuel injector components have been fabricated with zirconium diboride (ZrB2) powder. Stearic acid was selected as the binder. Values of SLS process parameters were chosen such that the green parts could be built with sharp geometrical features and that the sintered parts could have good mechanical properties. After binder burnout and sintering, the SLS fabricated ZrB2 test bars achieved 80% theoretical density, and the average flexural strength of the sintered samples was 195 MPa. These values demonstrate the feasibility of the SLS process for …

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Direct 3d Layer Metal Deposition, Jianzhong Ruan, Lie Tang, Todd E. Sparks, Robert G. Landers, Frank W. Liou Aug 2008

Direct 3d Layer Metal Deposition, Jianzhong Ruan, Lie Tang, Todd E. Sparks, Robert G. Landers, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multi-axis slicing for solid freeform fabrication (SFF) manufacturing processes can yield non-uniform thickness layers, or 3D layers. Using the traditional parallel layer construction approach to build such a layer leads to a staircase which requires machining or other post processing to form the desired shape. This paper presents a direct 3D layer deposition approach. This approach uses an empirical model to predict the layer thickness based on experimental data. The toolpath between layers is not parallel; instead, it follows the final shape of the designed geometry and the distance between the toolpath in the adjacent layers varies at different locations. …

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Product Focused Freeform Fabrication Education, Frank W. Liou, Ming-Chuan Leu Aug 2008

Product Focused Freeform Fabrication Education, Frank W. Liou, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Presented in this paper is our experience of teaching freeform fabrication to students at the Missouri University of Science and Technology, and to high school students and teachers. The emphasis of the curriculum is exposing students to rapid product development technologies with the goal of creating awareness to emerging career opportunities in CAD/CAM. Starting from solid modeling, principles of freeform fabrication, to applications of rapid prototyping and manufacturing in industry sponsored product development projects, students can learn in-depth freeform fabrication technologies. Interactive course content with hands-on experience for product development is the key towards the success of the program.

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Direct-To-Part Machining Waste Recycling Using Laser Metal Deposition, Todd E. Sparks, Frank W. Liou Aug 2008

Direct-To-Part Machining Waste Recycling Using Laser Metal Deposition, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser metal deposition typically uses metal powders as the build material of choice. The ability to reprocess waste materials using this technology would significantly reduce the material cost and cradle-to-grave energy content of parts produced using these methods. This capability will also greatly increase the utility of laser deposition, to potential industrial uses. This paper explores the usage of machining chips as an alternate source of build material. Topics covered include material handling, material preprocessing, and comparison to powder- based deposition.

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Modeling And Experimental Results Of Concentration With Support Material In Rapid Freeze Prototyping, Frances D. Bryant, Ming-Chuan Leu Aug 2008

Modeling And Experimental Results Of Concentration With Support Material In Rapid Freeze Prototyping, Frances D. Bryant, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Ice structures with complex geometries and overhung areas are created by the Rapid Freeze Prototyping (RFP) process in a sufficiently cool environment by freezing water into ice as the main material in conjunction with a eutectic dextrose-water solution as the sacrificial support material. The supported areas in an ice structure are removed via an increase in temperature in a separate environment after the structure is completely fabricated. To understand to what extent these two materials mix during fabrication, two methods of modeling the concentration changes that occur near the interface of the main and support materials have been developed. The …

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Microstructural Characterization Of Diode Laser Deposited Ti-6al-4v, Tian Fu, Zhiqiang Fan, Syamala R. Pulugurtha, Todd E. Sparks, Jianzhong Ruan, Frank W. Liou, Joseph William Newkirk Aug 2008

Microstructural Characterization Of Diode Laser Deposited Ti-6al-4v, Tian Fu, Zhiqiang Fan, Syamala R. Pulugurtha, Todd E. Sparks, Jianzhong Ruan, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser Direct Metal Deposition (DMD) is an effective approach to manufacturing or repairing a range of metal components. The process is a layer-by-layer approach to building up a three dimensional solid object. The microstructure influences mechanical properties of the deposited parts. Thus, it is important to understand the microstructural features of diode laser deposited parts. This paper presents a microstructure analysis of a diode laser deposited Ti-6Al-4V onto a Ti-6Al-4V substrate. laser deposited parts. This paper presents a microstructure analysis of a diode laser deposited Ti-6Al-4V onto a Ti-6Al-4V substrate.

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Layer-To-Layer Height Control For Laser Metal Deposition Processes, Lie Tang, Jianzhong Ruan, Todd E. Sparks, Robert G. Landers, Frank W. Liou Aug 2008

Layer-To-Layer Height Control For Laser Metal Deposition Processes, Lie Tang, Jianzhong Ruan, Todd E. Sparks, Robert G. Landers, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Laser Metal Deposition (LMD) height controller design methodology is presented in this paper. The height controller utilizes the Particle Swarm Optimization (PSO) algorithm to estimate model parameters between layers using measured temperature and track height profiles. The process model parameters for the next layer are then predicted using Exponentially Weighted Moving Average (EWMA). Using the predicted model, the powder flow rate reference profile, which will produce the desired layer height reference, is then generated using Iterative Learning Control (ILC). The model parameter estimation capability is tested using a four-layer deposition. The results demonstrate the simulation based upon estimated process …

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Design Of Embedded Resistance Heating Element Using Rapid Manufacturing Process, Ravi Philip, Todd E. Sparks, Frank W. Liou Aug 2007

Design Of Embedded Resistance Heating Element Using Rapid Manufacturing Process, Ravi Philip, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper discusses the design of heating element suitable for embedding in a rapid manufacturing process. A specific pattern is built using the laser deposition Process available at the University of Missouri--Rolla. A resistance heating element which is then cast into place using a castable refractory material, which acts as an electrical insulator. An application of this technology is for preheating the substrate before direct metal deposition.

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Experimental Investigation Of Effect Of Environment Temperature On Freeze-Form Extrusion Fabrication, Xiyue Zhao, Michael S. Mason, Tieshu Huang, Ming-Chuan Leu, Robert G. Landers, Greg Hilmas, Samuel J. Easley, Michael W. Hayes Aug 2007

Experimental Investigation Of Effect Of Environment Temperature On Freeze-Form Extrusion Fabrication, Xiyue Zhao, Michael S. Mason, Tieshu Huang, Ming-Chuan Leu, Robert G. Landers, Greg Hilmas, Samuel J. Easley, Michael W. Hayes

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing technique that extrudes ceramic loaded aqueous pastes layer by layer below the paste freezing temperature for component fabrication. A computer controlled 3-D gantry system has been developed for the FEF process. The system includes a temperature control subsystem that allows for fabrication of components below the paste freezing temperature. The low temperature environment allows for larger component fabrication. Comparisons in terms of layer thickness, self-sustaining ability, and system response were performed between 0⁰C and -20⁰C for alumina sample fabrications. The minimum deposition angles without use of support material have been determined for …

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Modeling And Simulation Of A Laser Deposition Process, Frank W. Liou, Zhiqiang Fan, Heng Pan, Kevin P. Slattery, Mary Kinsella, Joseph William Newkirk, Hsin-Nan Chou Aug 2007

Modeling And Simulation Of A Laser Deposition Process, Frank W. Liou, Zhiqiang Fan, Heng Pan, Kevin P. Slattery, Mary Kinsella, Joseph William Newkirk, Hsin-Nan Chou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A laser deposition process involves the supply of metallic powders into a laser-heated spot where the powder is melted and forms a melt puddle which quickly solidifies into a bead. In order to design an effective system, the laser beam, the powder beam, and their interactions need to be fully understood. In this paper, the laser-material interaction within the melt pool is reported using a multi-scale model: A macroscopic model to model mass, heat, and momentum transfer. Experiments were also conducted to validate the simulation model.

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Thermocouple Embedding For The Production Of A Substrate For Rapid Manufacturing, Rana Gunaratnam, Todd E. Sparks, Frank W. Liou Aug 2007

Thermocouple Embedding For The Production Of A Substrate For Rapid Manufacturing, Rana Gunaratnam, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper reports the results of a set of experiments testing methods to embed thermocouples during laser deposition. Various operating settings and shielding materials are explored. Temperature readings of the embedded thermocouples are compared with surface temperature readings taken by a non-contact digital pyrometer during the deposition process. Also, possibilities of using this information for system control are discussed.

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Modeling And Validation Of Temperature And Concentration For Rapid Freeze Prototyping, Frances D. Bryant, Ming-Chuan Leu Aug 2007

Modeling And Validation Of Temperature And Concentration For Rapid Freeze Prototyping, Frances D. Bryant, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid Freeze Prototyping is a solid freeform fabrication process that uses water as the main build material in a cold environment to create three-dimensional parts. A eutectic sugar-water solution (C6H12O6 – H2O) has been used as a sacrificial material in order to create complex 3D parts with features such as overhangs. A study of the interaction of the build and support materials is presented in this paper. The temperature of both materials during deposition and subsequent cooling is modeled using a semi-empirical model and a theoretical model. A concentration model is used to …

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Aqueous-Based Extrusion Fabrication Of Ceramics On Demand, Michael S. Mason, Tieshu Huang, Robert G. Landers, Ming-Chuan Leu, Greg Hilmas, Michael W. Hayes Aug 2007

Aqueous-Based Extrusion Fabrication Of Ceramics On Demand, Michael S. Mason, Tieshu Huang, Robert G. Landers, Ming-Chuan Leu, Greg Hilmas, Michael W. Hayes

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Aqueous-Based Extrusion Fabrication is an additive manufacturing technique that extrudes ceramic slurries of high solids loading layer by layer for part fabrication. The material reservoir in a previously developed system has been modified to allow for starting and stopping of extrusion process on demand. Design pros and cons are examined and a comparison between two material reservoir designs is made. Tests were conducted to determine the optimal deposition parameters for starting and stopping of the extrudate on demand. The collected test data is used to create a process model that describes the relationship between ram velocity and material extrusion rate. …

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Laser Deposition Cladding On-Line Inspection Using 3-D Scanner, Yu Yang, Todd E. Sparks, Jianzhong Ruan, Lan Ren, Frank W. Liou Aug 2007

Laser Deposition Cladding On-Line Inspection Using 3-D Scanner, Yu Yang, Todd E. Sparks, Jianzhong Ruan, Lan Ren, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser deposition directly deposits metal cladding to fabricate and repair components. In order to finish the fabrication or repair, 3-D shape of the deposition needs to be inspected, and thus it can be determined if it has sufficient cladding to fabricate a part after deposition process. In the present hybrid system in the Laser Aided Manufacturing Lab (LAMP) at the University of Missouri - Rolla, a CMM system is used to do the inspection. A CMM requires point-by-point contact, which is time consuming and difficult to plan for an irregular deposition geometry. Also, the CMM is a separate device, which …

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Numerical Simulation Of The Evolution Of Solidification Microstructure In Laser Deposition, Zhiqiang Fan, Todd E. Sparks, Frank W. Liou, Anand Jambunathan, Yaxin Bao, Jianzhong Ruan, Joseph William Newkirk Aug 2007

Numerical Simulation Of The Evolution Of Solidification Microstructure In Laser Deposition, Zhiqiang Fan, Todd E. Sparks, Frank W. Liou, Anand Jambunathan, Yaxin Bao, Jianzhong Ruan, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A predictive model is developed to simulate the evolution of the solidification microstructure during the laser deposition process. The microstructure model is coupled with a comprehensive macroscopic thermodynamic model. This model simulates dendritic grain structures and morphological evolution in solidification. Based on the cellular automata approach, this microstructure model takes into account the heterogeneous nucleation both within the melt pool and at the substrate/melt interface, the growth kinetics, and preferential growth directions of dendrites. Both diffusion and convection effects are included. This model enables prediction and visualization of grain structures during and after the deposition process. This model is applied …

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Variable Powder Flow Rate Control In Laser Metal Deposition Processes, Lie Tang, Jianzhong Ruan, Robert G. Landers, Frank W. Liou Aug 2007

Variable Powder Flow Rate Control In Laser Metal Deposition Processes, Lie Tang, Jianzhong Ruan, Robert G. Landers, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper proposes a novel technique, called Variable Powder Flow Rate Control (VPFRC), for the regulation of powder flow rate in laser metal deposition processes. The idea of VPFRC is to adjust the powder flow rate to maintain a uniform powder deposition per unit length even when disturbances occur (e.g., the motion system accelerates and decelerates). Dynamic models of the powder delivery system motor and the powder transport system (i.e., five-meter pipe, powder dispenser, and cladding head) are first constructed. A general tracking controller is then designed to track variable powder flow rate references. Since the powder flow rate at …

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Comparison Of Thermal Properties Of Laser Deposition And Traditional Welding Process Via Thermal Diffusivity Measurement, Yu Yang, Omoghene Osaze Obahor, Yaxin Bao, Todd E. Sparks, Jianzhong Ruan, Jacquelyn K. Stroble, Robert G. Landers, Joseph William Newkirk, Frank W. Liou Aug 2006

Comparison Of Thermal Properties Of Laser Deposition And Traditional Welding Process Via Thermal Diffusivity Measurement, Yu Yang, Omoghene Osaze Obahor, Yaxin Bao, Todd E. Sparks, Jianzhong Ruan, Jacquelyn K. Stroble, Robert G. Landers, Joseph William Newkirk, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser deposition is an effective process for mold and die repair. In order to improve the part repair quality, the process impact on thermal diffusivity and thermal conductivity needs to be understood for laser deposited, welded and virgin H13. In this paper, H13 tool steel samples were made by laser deposition, welding and virgin H13 and then cut into pieces. Experiments were conducted to investigate the thermal diffusivity and conductivity. A laser flash method is used to test these samples. The future work and opportunities are also summarized.

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Evaluation Of Mechanical Properties And Microstructure For Laser Deposition Process And Welding Process, Yaxin Bao, Jianzhong Ruan, Todd E. Sparks, Jambunathan Anand, Joseph William Newkirk, Frank W. Liou Aug 2006

Evaluation Of Mechanical Properties And Microstructure For Laser Deposition Process And Welding Process, Yaxin Bao, Jianzhong Ruan, Todd E. Sparks, Jambunathan Anand, Joseph William Newkirk, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser Aided Manufacturing Process (LAMP) can be applied to repair steel die/molds which are currently repaired using traditional welding process in industry. In order to fully understand the advantages of laser deposition repair process over traditional welded-repair process, the mechanical properties such as tensile strength and hardness of H13 tool steel samples produced by these two processes were investigated. The microstructure and fracture surface of the samples were analyzed using optical microscope and SEM (Scanning Electron Microscope). Moreover, depositions on substrates with different shapes were studied to evaluate the performance of LAMP on damaged parts with complicated geometric shape.

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A Review Of Layer Based Manufacturing Processes For Metals, Jianzhong Ruan, Todd E. Sparks, Zhiqiang Fan, Jacquelyn K. Stroble, Ajay Panackal, Frank W. Liou Aug 2006

A Review Of Layer Based Manufacturing Processes For Metals, Jianzhong Ruan, Todd E. Sparks, Zhiqiang Fan, Jacquelyn K. Stroble, Ajay Panackal, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The metal layered manufacturing processes have provided industries with a fast method to build functional parts directly from CAD models. This paper compares current metal layered manufacturing technologies from including powder based metal deposition, selective laser sinstering (SLS), wire feed deposition etc. The characteristics of each process, including its industrial applications, advantages/disadvantages, costs etc are discussed. In addition, the comparison between each process in terms of build rate, suitable metal etc. is presented in this paper.

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Three Dimensional Die Repair Using A Hybrid Manufacturing System, Lan Ren, Ajay Panackal Padathu, Jianzhong Ruan, Todd E. Sparks, Frank W. Liou Aug 2006

Three Dimensional Die Repair Using A Hybrid Manufacturing System, Lan Ren, Ajay Panackal Padathu, Jianzhong Ruan, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A dramatic reduction in the cost, energy and time can be achieved by pursuing part repairing especially for die industry. In this paper, repairing process development was carried out by a hybrid manufacturing system aiming at the prevalent kinds of die core damages which is worn-out or corroded surface. Surface patches pattern is used for generating tool path to repair the damaged faces. A user-friendly software tool was developed to facilitate the users. 3D repairing technology was also integrated which ensures the alignment when more than one damages need to be repaired without reloading the part. Realization of 3D surface …

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Numerical Simulation And Prediction Of Dilution During Laser Deposition, Zhiqiang Fan, Anand Jambunathan, Todd E. Sparks, Jianzhong Ruan, Yu Yang, Yaxin Bao, Frank W. Liou Aug 2006

Numerical Simulation And Prediction Of Dilution During Laser Deposition, Zhiqiang Fan, Anand Jambunathan, Todd E. Sparks, Jianzhong Ruan, Yu Yang, Yaxin Bao, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The laser additive manufacturing technique of laser deposition allows quick fabrication of fully-dense metallic components directly from Computer Aided Design (CAD) solid models. The applications of laser deposition include rapid prototyping, rapid tooling and part refurbishment. The development of an accurate predictive model for laser deposition is extremely complicated due to the multitude of process parameters and materials properties involved. In this work, a heat transfer and fluid flow model is developed. The model is used to predict dilution under varying process parameters for deposits of Ti-6Al-4V. Experimental validation of the predicted dilution is presented. The laser used is a …

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Applications Of A Hybrid Manufacturing Process For Fabrication And Repair Of Metallic Structures, Frank W. Liou, Kevin P. Slattery, Mary Kinsella, Joseph William Newkirk, Hsin-Nan Chou, Robert G. Landers Aug 2006

Applications Of A Hybrid Manufacturing Process For Fabrication And Repair Of Metallic Structures, Frank W. Liou, Kevin P. Slattery, Mary Kinsella, Joseph William Newkirk, Hsin-Nan Chou, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Since its appearance, rapid prototyping technology has been of interest to various industries that are looking for a process to produce/build a part directly from a CAD model in a short time. Among them, the direct metal deposition process is the only process which directly manufactures a fully dense metal part without intermediate steps. However, challenges of the direct metal deposition process include building overhang structures, producing precision surfaces, and making parts with complex structures. Coupled between the additive and the subtractive processes into a single workstation, the integrated process, or hybrid process, can produce a metal part with machining …

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Automation Of A Hybrid Manufacturing System Through Tight Integration Of Software And Sensor Feedback, Jacquelyn K. Stroble, Robert G. Landers, Frank W. Liou Aug 2006

Automation Of A Hybrid Manufacturing System Through Tight Integration Of Software And Sensor Feedback, Jacquelyn K. Stroble, Robert G. Landers, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a framework for the automation of the Laser Aided Manufacturing Process (LAMP) lab at the University of Missouri-Rolla. The groundwork for the proposed system involves the integration of the LabVIEW software package and a PXI-8195 real time controller with several sensors and actuators. The incorporation of all key control parameters into one virtual instrument will help achieve the goal of an automated hybrid system. To achieve this goal, a five-phase plan, which will be further discussed in the paper, has been developed. The first phase of this plan, which includes the deposition of a thin walled structure …

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Determination Of Transformation Matrix In A Hybrid Multi-Axis Laser-Aided Manufacturing System And Its Practical Implementation, Ajay Panackal Padathu Vijayan, Todd E. Sparks, Jianzhong Ruan, Frank W. Liou Aug 2006

Determination Of Transformation Matrix In A Hybrid Multi-Axis Laser-Aided Manufacturing System And Its Practical Implementation, Ajay Panackal Padathu Vijayan, Todd E. Sparks, Jianzhong Ruan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Laser Aided Manufacturing Process (LAMP) is a multi-axis hybrid manufacturing process comprised of both an additive process, laser deposition, and a subtractive process, CNC machining. Determination of transformation matrix is one of the most important tasks to bridge the gap between process planning (software) and real deposition/machining process. The first part of the paper discusses an algorithm for computing the position of point/points in three-dimensional space, using homogenous transformation matrices. The second part of the paper discusses about how the algorithm was used in practice to build 3-D parts and part-repair using hybrid manufacturing process.

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Effect Of Structured Laser Pulses On Grain Growth In H13 Tool Steel, Todd E. Sparks, Jianzhong Ruan, Zhiqiang Fan, Yaxin Bao, Frank W. Liou Aug 2006

Effect Of Structured Laser Pulses On Grain Growth In H13 Tool Steel, Todd E. Sparks, Jianzhong Ruan, Zhiqiang Fan, Yaxin Bao, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In metal solidification. the cooling rate is an important factor in determining the resultant grain structure of the material. The paper discusses the results of a feasibility study done to determine whether a laser pulse scheme can be designed to affect, and eventually control, the resultant microstructure of the deposited material. A factorial experimental approach is applied to determine the significant parameters affecting grain size and orientation. Parameters investigated include maximum pulse power, pulse frequency, pulse shape, and material feed rate. Particular attention is given to parameter combinations that can cause grain growth through the layer boundaries of the deposited …

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Freeform Extrusion Of High Solids Loading Ceramic Slurries, Part Ii: Extrusion Process Control, Michael S. Mason, Tieshu Huang, Robert G. Landers, Ming-Chuan Leu, Greg Hilmas Aug 2006

Freeform Extrusion Of High Solids Loading Ceramic Slurries, Part Ii: Extrusion Process Control, Michael S. Mason, Tieshu Huang, Robert G. Landers, Ming-Chuan Leu, Greg Hilmas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Part I of this paper provided a detailed description of a novel fabrication machine for high solids loading ceramic slurry extrusion processes and presented an empirical model of the ceramic extrusion process, viewing ram velocity as the input and extrusion force as the output. A constant extrusion force is desirable as it correlates with a constant material deposition rate and, thus, good part quality. The experimental results used to construct the model demonstrated that a constant ram velocity will not necessarily produce a constant extrusion force. In some instances the extrusion force increased until ram motor skipping occurred, and process …

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Freeform Extrusion Of High Solids Loading Ceramic Slurries, Part I: Extrusion Process Modeling, Michael S. Mason, Tieshu Huang, Robert G. Landers, Ming-Chuan Leu, Greg Hilmas Aug 2006

Freeform Extrusion Of High Solids Loading Ceramic Slurries, Part I: Extrusion Process Modeling, Michael S. Mason, Tieshu Huang, Robert G. Landers, Ming-Chuan Leu, Greg Hilmas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A novel, solid freeform fabrication method has been developed for the manufacture of ceramic-based components in an environmentally friendly fashion. The method is based on the extrusion of ceramic slurries using water as the binding media. Aluminum oxide (Al2O3) is currently being used as the part material and solids loading as high as 60 vol. % has been achieved. This paper describes a novel manufacturing machine that has been developed for the extrusion of high solids loading ceramic slurries. A critical component of the machine is the deposition system, which consists of a syringe, a plunger, …

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Workpiece Alignment For Hybrid Laser Aided Part Repair Process, Ajay Panackal Padathu, Todd E. Sparks, Frank W. Liou Aug 2005

Workpiece Alignment For Hybrid Laser Aided Part Repair Process, Ajay Panackal Padathu, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Work piece alignment is a key issue for hybrid laser aided part repair,a process utilizing both machining and laser deposition.Proper alignment can greatly improve the accuracy of the repair process.This paper introduces a method for aligning a physical work piece and a CAD model using a Renis aw touch probe and software tools. Also discussed is a model for computing 5-axis CNC positions based on a desired work piece orientation.

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Determination Of Dynamic Powder Modeling Parameters Via Optical Methods, Todd E. Sparks, Heng Pan, Frank W. Liou Aug 2005

Determination Of Dynamic Powder Modeling Parameters Via Optical Methods, Todd E. Sparks, Heng Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Dynamic parameters, such as restitution and friction coefficients are important for powder flow simulations of laser based deposition processes. These parameters are difficult to find, especially for industrial metal powders. This paper introduces an optical method for measuring restitution and friction coefficients. The free falling powder flow was illuminated by a laser sheet. In order to obtain particle velocity, streaks proportional to particle velocities was generated by laser pulse obtained by a chopper. Recorded imaged were analyzed to determine particle velocities both before and after various impact conditions as well as impact parameters.

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