Open Access. Powered by Scholars. Published by Universities.®

Manufacturing Commons™

Open Access. Powered by Scholars. Published by Universities.®

Missouri University of Science and Technology

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 271 - 300 of 336

Full-Text Articles in Manufacturing

Design For Manufacturing For Friction Stir Welding, Harish Bagaitkar Jan 2008

Design For Manufacturing For Friction Stir Welding, Harish Bagaitkar

Masters Theses

"This thesis is divided in two parts. In the first part, technical feasibility of implementing Friction Stir Welding (FSW) for automobile chassis fabrication is discussed using a case study. In the case study, Design for Manufacturing (DFM) principles are applied to manufacture an aluminum automobile chassis. Various DFM issues such as Tool Accessibility Issue, Joint Configuration Issue, and Fixture Support Issue along with relevant guidelines such as component geometry change and component elimination are discussed in the first section. Results show that more than 50% of the chassis joints can be welded using FSW technique. The second part of the …

Go to article

Sorting Automated Concept Generator Results Based On Manufacture And Assembly Concerns, Kerry Ryan Poppa Jan 2008

Sorting Automated Concept Generator Results Based On Manufacture And Assembly Concerns, Kerry Ryan Poppa

Masters Theses

"Early in the design process, it is desirable to produce a large number of potential solutions. Completely exploring a problem's solution space is an unreasonable expectation for an unaided designer or design team. Computational tools have emerged to help designers more fully explore possible solutions. These automated concept generators use knowledge from existing designs and the desired functionality of the new product to suggest solutions. Existing automated concept generation methods produce many candidate solutions, but produce unmanageably large sets of solutions. Techniques are needed to organize the set of concepts into smaller groups, more easily parsed by the human designer. …

Go to article

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.

Go to article

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 …

Go to article

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.

Go to article

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.

Go to article

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 …

Go to article

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. …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

E-Design Tools For Friction Stir Welding: Cost Estimation Tool, Pradeep Kumar Tipaji Jan 2007

E-Design Tools For Friction Stir Welding: Cost Estimation Tool, Pradeep Kumar Tipaji

Masters Theses

"A cost model is an important tool for product design and material selection. An efficient and effective cost estimation tool is necessary for early design evaluation. In this paper, cost estimation models that estimate the production cost for Metal Inert Gas (MIG), Friction Stir (FS), and Friction Stir Spot (FSS) welded joints are presented. These models determine the cost incurred to fabricate each joint along with a detailed explanation of each cost component. Each cost component has been closely analyzed and major cost components have been included in the cost model"--Abstract, page iv.

Go to article

Towards A Methodology For Integrated Freeform Manufacturing Systems Development With A Control Systems Emphasis, Jacquelyn K. Stroble Jan 2007

Towards A Methodology For Integrated Freeform Manufacturing Systems Development With A Control Systems Emphasis, Jacquelyn K. Stroble

Masters Theses

"A variety of fully integrated Freeform Fabrication (FFF) systems have been developed, a selected group for research and several for commercialization. The design methodology behind most of them is not documented, standardized, or rational. It is important to understand that the final product from any integrated system is affected not only by the unit manufacturing processes themselves, but also by the extent the individual units are assimilated into an integrated process. Thus, a scheme consisting of eight steps and the salient five elements necessary to create or retrofit an existing system to achieve an Integrated Freeform Manufacturing System (FFMS) is …

Go to article

Mechanical Properties And Microstructure Study For Direct Metal Deposition Of Titanium Alloy And Tool Steel, Yaxin Bao Jan 2007

Mechanical Properties And Microstructure Study For Direct Metal Deposition Of Titanium Alloy And Tool Steel, Yaxin Bao

Masters Theses

"This thesis is focused on the research about DMD (Direct Metal Deposition) which is an additive manufacturing process and used in various engineering applications such as producing fully dense and net shape productions in difficult-to-machine materials. In this study, the microstructure was analyzed through optical microscopy and some mechanical properties were tested with different equipments such as SEM (Scanning Electron Microscopy) and micro-hardness tester...In summary, this thesis validated that DMD process can be improved through surface treatments and is capable of repairing molds for die casting industry"--Introduction, page 1.

Go to article

Optimal Formation Of Supplier Networks For Product Design And Production Phases To Realize An Evolving Product Family, Padmavathi K. Pakala Jan 2007

Optimal Formation Of Supplier Networks For Product Design And Production Phases To Realize An Evolving Product Family, Padmavathi K. Pakala

Masters Theses

"Due to rapid changes in customer requirements and vast improvements in technology, many product development companies have identified strategies like time-to-market (TTM) compression and product family development as critical for attaining success in today's hyper-competitive markets. Compressing the TTM, to a large extent, is dependent on the suppliers and the project execution skills of the integrator companies. This study presents a methodology for selecting suppliers for two significant phases of the product realization process, namely, product design and production. The proposed methodology uses a two-stage approach for supplier selection where suppliers for product design are selected in the first stage …

Go to article

On-Line Inspection And Thermal Properties Comparison For Laser Deposition Process, Yu Yang Jan 2007

On-Line Inspection And Thermal Properties Comparison For Laser Deposition Process, Yu Yang

Masters Theses

"This thesis is focused on comparing the laser deposition cladding with intended design model and comparing the effect of laser deposition process on thermal properties with traditional welding process. It is research on two aspects of laser deposition cladding. The first part of the thesis is aimed at solving the geometric inspection of laser deposition cladding, and the second part is for comparing the thermal properties of laser deposition cladding to samples of conventional welding process"--Introduction, page 1.

Go to article

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.

Go to article

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.

Go to article

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.

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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.

Go to article

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 …

Go to article

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 …

Go to article

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, …

Go to article

Freeze-Spray Processing Of Layered Ceramic Composites, Qiang Fu, Oratai Jongprateep, Ashlee Abbott, Fatih Dogan Aug 2006

Freeze-Spray Processing Of Layered Ceramic Composites, Qiang Fu, Oratai Jongprateep, Ashlee Abbott, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Thermal gradients and associated stresses are critical in designing with ceramic composites having low thermal conductivity. In order to reduce the stresses from thermal gradients, compositional gradients are employed in designing of composite structures. This study addresses development of freeze-spray process to fabricate layered ceramic structures with controlled layer thickness and microstructural development. The composites were processed by spraying of ceramic slurries with low binder content and relatively high solids loadings (up to 40 vol%) on a cooled substrate. The frozen parts were freeze-dried and sintered at elevated temperatures. The relationship between microstructural development and thermal expansion behavior of Al …

Go to article

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.

Go to article

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.

Go to article

First Prev Next Last