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Missouri University of Science and Technology

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Articles 271 - 286 of 286

Full-Text Articles in Manufacturing

Empirical Modeling And Vision Based Control For Laser Aided Metal Deposition Process, Mallikharjuna R. Boddu, Srinivas Musti, Robert G. Landers, Sanjeev Agarwal, Frank W. Liou Aug 2001

Empirical Modeling And Vision Based Control For Laser Aided Metal Deposition Process, Mallikharjuna R. Boddu, Srinivas Musti, Robert G. Landers, Sanjeev Agarwal, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper gives a brief description of the laser aided manufacturing process. Empirical models describing the process dynamics of the laser aided metal deposition process is developed based on some of the models found in the literature. These models provide the basis for process planning and real time control. An embedded vision system, a two color temperature sensor, and a laser displacement sensor are incorporated for real time monitoring and control of the deposition process. The temperature profile of the surface and geometric characteristics of the melt pool are studied to ensure consistent operation of the process.

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Control Of Laser Cladding For Rapid Prototyping -- A Review, Mallikharjuna R. Boddu, Robert G. Landers, Frank W. Liou Aug 2001

Control Of Laser Cladding For Rapid Prototyping -- A Review, Mallikharjuna R. Boddu, Robert G. Landers, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Lasers have wide-ranging applications in the manufacturing field (e.g., cladding, welding, cutting, machining, drilling). Extensive work is being conducted to apply laser cladding as a Rapid Prototyping (RP) process. In this paper the authors illustrate various principles of laser cladding in rapid prototyping. Important process parameters for the control of the laser cladding process are discussed as well as the experimental methods adopted, and results obtained by, various authors.

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Research And Development Of A Hybrid Rapid Manufacturing Process, Frank W. Liou, J. Choi, Robert G. Landers, Vijayakumar Janardhan, S. N. Balakrishnan, Sanjeev Agarwal Aug 2001

Research And Development Of A Hybrid Rapid Manufacturing Process, Frank W. Liou, J. Choi, Robert G. Landers, Vijayakumar Janardhan, S. N. Balakrishnan, Sanjeev Agarwal

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents the research and development of a hybrid rapid manufacturing process being developed at the University of Missouri--Rolla. This process includes a laser deposition and a 5- axis CNC milling system. By combining laser deposition and machining processes, the resulting hybrid process can provide greater build capability and better accuracy and surface finish. The hybrid process can build some features that are difficult to build in using a purely deposition processes. The issues and related approaches in the research and development of the hybrid deposition-machining process, including laser deposition process, system design and integration, process planning, and sensor …

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Skeleton-Based Geometric Reasoning For Adaptive Slicing In A Five-Axis Laser Aided Manufacturing Process System, Kunnayut Eiamsa-Ard, Jun Zhang, Frank W. Liou Aug 2001

Skeleton-Based Geometric Reasoning For Adaptive Slicing In A Five-Axis Laser Aided Manufacturing Process System, Kunnayut Eiamsa-Ard, Jun Zhang, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multi-axis Laser Aided Manufacturing Process (LAMP) is an additive manufacturing process similar to laser cladding. This process can produce full functional parts [1]. Traditional Layered Manufacturing processes produce parts with limited surface quality; and also the build time is often long due to the deposition of sacrificial support structure. The multiple degrees of freedom endow the LAMP system a capability to build parts without support structure. An algorithm for adaptive slicing based on skeleton is presented in this paper. The skeleton is useful for many applications such as feature recognition, robot path planning, shape analysis, and etc [2]. The near …

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Laser Additive Manufacturing Process Planning And Automation, Jun Zhang, Jianzhong Ruan, Frank W. Liou Aug 2000

Laser Additive Manufacturing Process Planning And Automation, Jun Zhang, Jianzhong Ruan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a Laser Additive Manufacturing Process Planning (LAMPP) being developed at the University of Missouri-Rolla. The off-line planning recognizes difficult-to-build features from an STL file, selects optimal part orientation and building directions based on the skeleton information of the object geometry, and optimizes the sub-process sequences for deposition and machining. During the optimization of the subpart building processes, collaboration between the deposition process planner and the machining process planner is needed to check the deposition availability and machinability. As a result, tool paths for both the laser head and the machining head are automatically generated.

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Investment Casting With Ice Patterns Made By Rapid Freeze Prototyping, Wei Zhang, Ming-Chuan Leu, Chao Feng, Rong Ren, Renjie Zhang, Qingping Lu, Jubu Jiang, Yongnian Yan Aug 2000

Investment Casting With Ice Patterns Made By Rapid Freeze Prototyping, Wei Zhang, Ming-Chuan Leu, Chao Feng, Rong Ren, Renjie Zhang, Qingping Lu, Jubu Jiang, Yongnian Yan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the most promising applications of rapid freeze prototyping (RFP) is making metal parts by investment casting with the built ice parts. The integration of RFP and investment casting allows fast creation of complex net-shape metal parts directly from their CAD models. The advantages of doing so include no part geometric complexity limitation, no experience of parting line design and assembling needed, clean and low-cost of process operation, and good performance. In this paper, we will present our recent study on binder selection, slurry making, ceramic shell making, and the casting results of the metal parts.

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Determination And Improvement Of Building Speed In Rapid Freeze Prototyping, Wei Zhang, Guanghua Sui, Ming-Chuan Leu Aug 2000

Determination And Improvement Of Building Speed In Rapid Freeze Prototyping, Wei Zhang, Guanghua Sui, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid freeze prototyping (RFP) is a solid freeform fabrication process that builds an ice part by rapidly freezing water in a layer by layer manner. One advantage of this process is the ability to build ice parts faster than other SFF processes. The factors that affect the speed of contour building and interior filling in RFP are identified. The influence of these factors is analyzed through heat transfer and material flow analyses. A model based on heat transfer analysis is proposed to determine the maximum achievable speed of contour building under stable conditions. Experiments are conducted to validate the performance …

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Study On Water Deposit In Rapid Freeze Prototyping Process, Guanghua Sui, Weihan Zhang, Ming-Chuan Leu Aug 2000

Study On Water Deposit In Rapid Freeze Prototyping Process, Guanghua Sui, Weihan Zhang, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid Freeze Prototyping (RFP) builds a three-dimensional ice part according to its CAD model by depositing and rapidly freezing water in a layer-by-layer manner. To study the water deposit in RFP, assumptions are made based on the deformation of water droplet impinging on a flat substrate, the thermal analysis of a new layer of water deposit, and the characteristics of solidification of a water drop. The equations governing the cross-sectional profile of the water deposit are then established. A model of water deposit is proposed by simplifying the equations under our experimental conditions in RFP. By using this model, equations …

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Process Modeling, Monitoring And Control Of Laser Metal Forming, N. Munjuluri, Sanjeev Agarwal, Frank W. Liou Aug 2000

Process Modeling, Monitoring And Control Of Laser Metal Forming, N. Munjuluri, Sanjeev Agarwal, Frank W. Liou

Electrical and Computer Engineering Faculty Research & Creative Works

Laser Metal Forming (LMF) process is one of the prominent Rapid Prototyping (RP) process that can be used to develop functional and fully dense metal parts. This paper addresses process modeling, monitoring and control of a laser metal forming system currently under development at Laser Aided Manufacturing Processes (LAMP) laboratory at University of Missouri--Rolla. This LMF system is based on a 2.5kW Nd:YAG laser as energy source and integrates five axis metal deposition and five axis machining. The current paper is aimed at characterization of effects of operating parameters such as traverse speed, mass flow-rate and laser power on the …

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Assessment Of Environmental Performance Of Rapid Prototyping And Rapid Tooling Processes, Yanchun Luo, Ming-Chuan Leu, Zhiming Ji Aug 1999

Assessment Of Environmental Performance Of Rapid Prototyping And Rapid Tooling Processes, Yanchun Luo, Ming-Chuan Leu, Zhiming Ji

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A method for assessing the environmental performance of solid freeform fabrication (SFF) based rapid prototyping and rapid tooling processes is presented in this paper. In this method of assessment, each process is divided into a number of life stages. The environmental effect of each process stage is analyzed and evaluated based on an environmental index utilizing the Eco-indicators that were compiled by PreConsultants of the Netherlands. The effects of various life stages are then combined to obtain the environmental performance of a process. In the assessment of SFF processes, we consider the material use in the fabrication of a part, …

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An Experimental And Analytical Study Of Ice Part Fabrication With Rapid Freeze Prototyping, Wei Zhang, Ming-Chuan Leu, Guanghua Sui, Zhiming Ji Aug 1999

An Experimental And Analytical Study Of Ice Part Fabrication With Rapid Freeze Prototyping, Wei Zhang, Ming-Chuan Leu, Guanghua Sui, Zhiming Ji

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid Freeze Prototyping (RFP) is a new solid freeform fabrication process that builds an ice part by rapidly freezing water layer by layer. In this paper, we will present our recent progress in the development of this novel process. An experimental system has been built for conducting the research. It consists of an XY-table and Z-stroke driven by micro-stepping motors and a water dispensing and deposition subsystem which incorporates a solenoid valve and a syringe pump placed inside a freezer. Simple heat transfer analysis is made to help select proper values of process parameters and predict part building failures. Example …

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Rapid Tooling By Integrating Electroforming And Solid Freeform Fabrication Techniques, Bo Yang, Ming-Chuan Leu Aug 1999

Rapid Tooling By Integrating Electroforming And Solid Freeform Fabrication Techniques, Bo Yang, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper describes a rapid tooling process that integrates solid freeform fabrication (SFF) with electroforming to produce metal tools including molds, dies, and electrical discharge machining (EDM) electrodes. Based on experimental data analysis, the geometry and material of the SFF part, the properties of the electroformed metal, and the process parameters are significant factors that cause inaccuracy in the manufactured tools. Thermomechanical modeling and numerical simulation is used to determine the geometry of the SFF part and the electroform thickness for minimizing the manufacturing time and cost while satisfying the tooling accuracy requirement.

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Shell Cracking In Investment Casting With Laser Stereolithography Patterns, W. L. Yao, Ming-Chuan Leu Aug 1998

Shell Cracking In Investment Casting With Laser Stereolithography Patterns, W. L. Yao, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents an investigation of ceramic shell cracking during the burnout process in investment casting with internally webbed laser stereolithography patterns. We hypothesize that shell cracking will occur when the rupture temperature of the ceramic shell is lower than both the glass transition temperature of the pattern material and the web· link buckling temperature. The hypothesis is validated by our experimental observations which confirm the numerical predictions from our finite element analysis. This provides a basis for design of the internal web geometry of a lithography pattern and evaluation of the burnout process with such a pattern. We show …

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Rapid Freezing Prototyping With Water, Wei Zhang, Ming-Chuan Leu, Zhiming Ji, Yongnian Yan Aug 1998

Rapid Freezing Prototyping With Water, Wei Zhang, Ming-Chuan Leu, Zhiming Ji, Yongnian Yan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid Freezing Prototyping (RFP) with water is a novel solid freeform fabrication technique that can generate three-dimensional ice objects by depositing and rapidly freezing water layer by layer. The support where necessary is made of brine whose. freezing point is lower than. pure water. After building the part, the support can be removed by utilizing the melting temperature difference between brine and water. Preliminary experiments have shown that the ice patterns produced by this technique can be used for design visualization and silicone molding. This paper will present the concept and some experimental results of the RFP process as well …

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Recent Developments In Extrusion Freeform Fabrication (Eff) Utilizing Non-Aqueous Gel Casting Formulations, Greg Hilmas, John L. Lombardi, Robert A. Hoffman, Kevin Stuffle Aug 1996

Recent Developments In Extrusion Freeform Fabrication (Eff) Utilizing Non-Aqueous Gel Casting Formulations, Greg Hilmas, John L. Lombardi, Robert A. Hoffman, Kevin Stuffle

Materials Science and Engineering Faculty Research & Creative Works

Extrusion Freeform Fabrication (EFF) was shown to be an extremely versatile method for fabricating Functionally Graded Materials (FGMs) The approach is inexpensive and potentially feasible for grading between any thermodynamically compatible ceramic-metal, ceramic-ceramic, or metal-metal material combination. Several material systems were investigated in this study including alumina-304 stainless steel, zirconia-304 stainless steel, alumina-Inconel 625, zirconiaInconel625, alumina-nickel aluminide, zirconia-nickel aluminide, titanium carbide-InconeI625, titanium diboride-nickel aluminide, and tungsten carbide-nickel aluminide. A controlled gradient was demonstrated between the end members for all of the above compositions. The FGMs were hot pressed to achieve near theoretical densities, providing flexural strengths as high as 1000 …

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Simulation Modeling In Manufacturing Cell Design, Debra A. Hunke Apr 1991

Simulation Modeling In Manufacturing Cell Design, Debra A. Hunke

Opportunities for Undergraduate Research Experience Program (OURE)

The interwoven phases of the manufacturing process in Computer Integrated Manufacturing (CIM) require a carefully designed facility. Simulation modeling can be combined with other techniques to provide a rigorous methodology for CIM system design. This paper describes CIM, simulation ana their relationship. A case study demonstrates the described methodology in the design of a flexible manufacturing cell.

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