Mechanical Engineering Commons^™

Designing And Manufacturing Microelectronic Packages For High-Power Light-Emitting Diodes, Brian Wright, Jianbiao Pan, Richard Savage

Industrial and Manufacturing Engineering

A new microelectronic package was designed for a high-power light-emitting diode (LED). The objective was to build a package that enables the LED to operate with currents as high as 2 Amps. An innovative thin-film interface has been developed to electrically connect the cathode of the LED die to a 22AWG Cu wire. This thin-film interface is wirebondable and solderable, and consists of three layers: Au, Ni93/V7, and Si. Four 1 mil Au wirebonds, supporting 2A of maximum current, connect the Au thin-film to the LED die cathode. Sn96Ag4 solder is used for connecting the Ni93/V7 thin-film to the 22AWG …

In-House Development Of Scheduling Decision Support Systems: Case Study For Scheduling Semiconductor Device Test Operations, Tali Freed, K. H. Doerr, T. Chang

Industrial and Manufacturing Engineering

Most manufacturing processes can benefit from an automated scheduling system. However;: the design of a fast, computerised scheduling system that achieves high-quality results and requires minimal resources is a difficult undertaking. Efficient .. scheduling of a semiconductor device test facility requires an information system that provides good schedules quickly. Semiconductor device testing-is the last stage of the long semiconductor manufacturing process, and therefore. is subjected to customer service pressures. The cost of an off-the-shelf computerised scheduling system may he prohibitive for many companies. In addition, many companies are taken aback by other characteristics of off-the-shelf scheduling systems, such as code …

Fabrication Of Functionally Graded 3a/5a Zeolites By Electrophoretic Deposition, X. Wang, E. A. Olevsky, E. Bruce, M. B. Stern, D. T. Hayhurst

Industrial and Manufacturing Engineering

Functionally graded zeolites of molecular sieve type 3A and 5A are deposited by electrophoretic deposition (EPD) from acetone suspension with 8% volume concentration of n-butylamine as particle charging agent. The EPD characteristics of both 3A and 5A suspensions are studied. Functionally graded zeolite 3A/5A deposits are obtained at 200 V DC. Energy dispersive X-ray dispersion (EDX) analysis results confirm the graded structure. The deposited zeolites are also analysed by scanning electron microscopy (SEM). The factors influencing the deposition process are discussed.

The Benefits Of Automatic Data Collection In The Fresh Produce Supply Chain, Ryan Charles Panos, Tali Freed

Industrial and Manufacturing Engineering

The potential for RFID based systems to improve the safety and efficiency of a supply chain with rapidly decaying products and strict health standards is creating pressure to adopt RFID in several agricultural industries. A handful of fresh produce industry leaders currently participate in mandated pilot projects, while the industry as a whole is still intimidated by the perceived cost of RFID. Therefore in this study we attempt to validate the correlation between performance and automated data collection, paving the way to economic justification of investment in data collection technologies, such as barcode and RFID.

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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

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 …

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 …

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.

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 …

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.

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. …

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.

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 …

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 …

Fabrication Of Net-Shape Functionally Graded Composites By Electrophoretic Deposition And Sintering: Modeling And Experimentation, E.A. Olevsky, X. Wang, A. Maximenko, M.A. Meyers

Industrial and Manufacturing Engineering

It is shown that electrophoretic deposition (EPD) sintering is a technological sequence that is capable of producing net-shape bulk functionally graded materials (FGM). By controlling the shape of the deposition electrode, components of complex shapes can be obtained. To enable sintering net-shape capabilities, a novel optimization algorithm and procedure for the fabrication of net-shape functionally graded composites by EPD and sintering has been developed. The initial shape of the green specimen produced by EPD is designed in such a way that the required final shape is achieved after sintering-imposed distortions. The optimization is based on a special innovative iteration procedure …

Investigation Of The Lead-Free Solder Joint Shear Performance, James Webster, Jianbiao Pan, Brian J. Toleno

Industrial and Manufacturing Engineering

Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The purpose of this study is to investigate the effects of reflow profile and thermal shock on the shear performance of eutectic SnPb (SnPb) and Sn3.0Ag0.5Cu (SAC305) solder joints. Test boards were assembled with four different sized surface mount chip resistors (1206, 0805, 0603 and 0402). Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb were developed with three levels of peak temperature (12ºC, 22ºC, and 32ºC above solder liquidus temperature, or 230ºC, 240ºC, and 250ºC for SAC …

Synthesis Of Gold Micro- And Nano-Wires By Infiltration And Thermolysis, E.A. Olevsky, X. Wang, E. Bruce, M.B. Stern, S. Wildhack, F. Aldinger

Industrial and Manufacturing Engineering

An approach for synthesizing micro- and nano-sized gold wires by infiltration and thermolysis is investigated. A porous ZrO₂ ceramic preform with aligned pores obtained by unidirectional freezing and freeze-drying is employed as an infiltration template. The sintered porous ZrO₂ preform is then infiltrated by a brushing gold solution. The thermolysis is conducted at 600 °C in air. Micro- and nano-sized gold wires are developed within the walls of the pores after thermolysis. The diameter of the gold wires ranges from several hundred nanometers to several microns.

Backward And Forward Compatibility, Jianbiao Pan, Jasbir Bath, Xiang Zhou, Dennis Willie

Industrial and Manufacturing Engineering

In response to the European Union (EU) Restriction of Hazardous Substances (RoHS) and other countries’ impending lead-free directives, the electronics industry is moving toward lead-free soldering. Total lead-free soldering requires not only lead-free solder paste but also lead-free printed circuit board (PCB) finish and lead-free component/packages. Transitioning tin-lead (SnPb) soldering to totally lead-free soldering is a complex issue and involves movement of the whole electronics industry supply chain. In reality, there is a transition period.

Iii Finishing, Lapping, Honing And Polishing: Processes, Characterisation And Novel Techniques-Experimental Research On Ultra-Smooth Surface Polishing Based On Two-Dimensional Vibration Of Liquid, Zhong Ning Guo, X. Z. Huang, Z. G. Huang, Z. Q. Yu, T. M. Yue, Wing Bun Lee

Faculty Publications

No abstract provided.