Mechanical Engineering Commons^™

The Use Of Confidence Intervals For The Control Limits Of X¯ And S Control Charts, Daniel A. Lopez

Theses and Dissertations - UTB/UTPA

This research focuses on the variation observed on the control limits of X¯ and S control charts, due to the sampling schemes. In previous studies it has been shown that the estimated control limits derived by a small number of subgroups does not help in setting up reliable control limits. It has also been shown that estimating control limits from a large number of subgroups is not a feasible option. In this research quantile tables will be derived by sampling from the standard normal distribution and used to explain the effects of sampling on the control limits. The tables will …

Development Of A Statistical Model For Process Control To Eliminate Sink Marks In Injection Molded Products, Kurt Frederick Hayden

Masters Theses

Customer demands for high-quality, defect-free injection-molded products are ever increasing. In order to satisfy these quality requirements, much effort is spent monitoring and controlling variable data such as cycle time, part weight, and dimensions. Attribute defects such as sink or splay are often overlooked in the development of process control systems. However, customers reject products because of these attribute defects. Industrial control systems based upon process variables and product design variables can detect conditions that may result in the molding of products with attribute defects. The systems can then correct the process prior to the molding of these defective products. …

Determination Of Wall Thickness And Height When Cutting Various Materials With Wire Electric Discharge Machining Processes, Sangseop Kim

Theses and Dissertations

This thesis looks at the capabilities of cutting thin webs on Wire EDM machines that are difficult or impossible to machine using conventional methods. Covered is an investigation of how different material and web thickness affect the capability of machining thin-walled parts.

Five different metals are used for the test; Aluminum 6061 T6, Yellow Brass SS360, 420 Stainless Steel, D2 unheat-treated tool steel 25-30 RC, and D2 heat-treated tool steel 60-65 RC. The small parts were cut to a 6mm (0.2362 inch) height with six different wall thicknesses: 0.30mm (0.0118 inch), 0.25mm (0.0098 inch), 0.20mm (0.0078 inch), 0.15mm (0.0059 inch), …

A Tool Wear Comparative Study In Turning Versus Computer Simulation In 1018 Steel, Woodrow D. Miner

Theses and Dissertations

The material removal process uses cutting tools in order to produce the desired shape of the workpiece. Tool wear has been a problem for cutting tools, since cutting tools wear and break. Research has been accomplished in the tool wear field for tool life and more recently tool wear. The computer generation has created a method to simulate the material removal process. These computer simulations model the cutting tool reaction with the workpiece. Many of the simulation models use finite element analysis to calculate the reaction of the cutting tool. Different finite element models are being used throughout the world …

The Purposes And Evaluation Methods For State Residential General Contractor Licensing, James Ellis Fenn

Theses and Dissertations

The main topic in the licensing debate is whether licensing affects construction quality. Available literature and previous studies indicate that it does not. The real question is not whether licensing improves quality, but whether the improving quality is the actual purpose of licensing. There is little information available on the purpose of licensing as defined by state licensing departments as well as a general lack of information on how states evaluate whether licensing is fulfilling the intended purpose. In order to effectively resolve some of the issues surrounding the construction licensing debate, the true purpose of licensing and the methods …

Machine Vision Course For Manufacturing Engineering Undergraduate Students, Jose Macedo, Kurt Colvin, Daniel Waldorf

Industrial and Manufacturing Engineering

A 10-week course was designed with funding from the Society of Manufacturing Engineers (SME) and input from industry representatives, to offer upper division engineering students a course on advanced automation. The objective was to provide engineering students theoretical and hands-on practical experience with automation technologies that will be of prime importance over the next decade: data acquisition and instrumentation, machine vision and motion control. This paper describes the machine vision portion of that class. It describes important concepts, hands-on equipment, and labs developed for this course, as well as examples of student projects from Spring Quarter, 2004. The course and …

Lead-Free Solder Joint Reliability – State Of The Art And Perspectives, Jianbiao Pan, Jyhwen Wang, David M. Shaddock

Industrial and Manufacturing Engineering

There is an increasing demand for replacing tin-lead (Sn/Pb) solders with lead-free solders in the electronics industry due to health and environmental concerns. The European Union recently passed a law to ban the use of lead in electronic products. The ban will go into effect in July of 2006. The Japanese electronics industry has worked to eliminate lead from consumer electronic products for several years. Although currently there are no specific regulations banning lead in electronics devices in the United States, many companies and consortiums are working on lead-free solder initiatives including Intel, Motorola, Agilent Technologies, General Electric, Boeing, NEMI …

The Limits Of Reflexive Design In A Secrecy-Based Organization, Michael W. Stebbins, Tali Freed, A.B. (Rami) Shani, Kenneth H. Doerr

Industrial and Manufacturing Engineering

No abstract provided.

An Acoustic Fluid-Structure Simulation Of A Therapeutic Ultrasound Wire Waveguide Apparatus, Graham Gavin, M. Hashmi, Finbar Dolan, Garret Mcguinness

Conference Papers

The use of high-power low-frequency ultrasound transmitted down small diameter wire waveguides is an emerging technology that may have potential in the treatment of complicated atherosclerotic plaques in cardiovascular surgery. This form of energy delivery results in vibrating the distal-tip of the wire waveguide disrupting material by means of direct contact ablation and also cavitation, pressure waves and acoustic streaming in the surrounding fluid. This work describes a numerical acoustic fluid-structure model of the ultrasound wire waveguide and blood surrounding the distal tip. The structural analysis of the model predicts the natural frequencies of the waveguide and shows the extent …

Investment Casting Using Ice Patterns -- Solid Mold And Shell Mold Methods, Harish Jose

Masters Theses

"This thesis focuses on the development and implementation of the investment casting process using ice patterns. The traditional method of the investment casting process involves using wax patterns. Wax patterns tend to expand during the dewaxing process, and this causes stress on the shell wall which can eventually lead to the breaking of the wall. Ice patterns on the other hand shrink when heated. This is a very desirable property for the investment casting process. The process of dewaxing (dewatering) of ice patterns can be achieved by keeping the shells at room temperature, instead of heating the shell in an …

Application Of Laser Aided Manufacturing Process For Functionally Graded Thermal Barrier Coatings, Yashodhan Joshi

Masters Theses

"Laser Aided Manufacturing Process (LAMP) is a rapid prototyping process used to build three dimensional functional metal and ceramic parts. The process developed in the LAMP laboratory at University of Missouri-Rolla uses a 5-axis fadal CNC machine and a 2.5 KW Nd:YAG (TEM₀₀) Rofin Sinar laser. The laser power and metal/ceramic powder are the input along with auxiliary systems such as shielding gas delivery, RT data acquisition, coolant system. The hybrid process makes use of metal deposition and machining to obtain parts meeting design tolerances.

LAMP is used to improve upon the process of Thermal Barrier Coating (TBC) …

Development Of A Flying Eye: A Project-Based Learning Experience, Sema E. Alptekin, Dianne Deturris, Daniel J. Macy, Jon E. Ervin

Industrial and Manufacturing Engineering

The paper describes the design for manufacturability of a prototype product as part of a manufacturing engineering capstone course. The product chosen was a vertically launched unmanned aerial vehicle (UAV)—the “Flying Eye.” The Flying Eye is an autonomous parafoil surveillance platform quipped with sensors, controllers, mechanical components, and software. Once the autonomous UAV is deployed, it is designed to follow a predetermined flight path down to the ground. The design effort of the prototype device took place over a three-year period as a collaborative effort between the Aerospace Engineering and Industrial and Manufacturing Engineering departments at California Polytechnic State University. …

The Evidence For A Nascent Biotechnology Cluster In Cork, John W. Hobbs

Theses

Over the past 30 years, encouraged by Ireland’s low rate of corporation tax (currently 12.5 %), and active promotion of FDI by the IDA, foreign owned pharmaceutical plants have set up and multiplied in the Cork area. To Ireland’s advantages of a low tax rate, an English speaking population, a pro-business environment and membership of EU, Cork offered the added attractions of a deepwater port and large natural harbour, good freight connections, an international airport, an educated workforce and excellent sporting and leisure facilities for sailing, golf, etc. (Pfizer, Eli Lilly, Novartis, GlaxoSmithKline, Johnson & Johnson and Schering Plough have …

Development And Performance Characteristics Of An Ultrasound Angioplasty Device, Graham Gavin, Garrett Mcguinness, Finbar Dolan, M.S. J. Hashmi

Conference Papers

INTRODUCTION The effect of atherosclerosis is well documented and many procedures such as balloon angioplasty and stentimplantation have been developed to reopen occluded arteries. However, there are considerable differences in the material properties of various atherosclerotic lesions as they develop. Many authors have suggested that rigid calcified plaques may require specific procedures that target this rigid material through de-bulking or complete removal (Salunke et al, 1997). Ultrasound angioplasty is the delivery of high power low frequency ultrasound via a wire waveguide to the lesion location. This results in distal tip wire displacements of up to 100um peak-to-peak (p-p) at frequencies …

New Product Launch Decisions Under Competition And Uncertainty: A Real Options And Game-Theoretic Approach To New Product Development, James O. Ostler

Theses and Dissertations

New product development is central to many firms' future success. Not only as a means to continue to maintain their piece of the market, but product development can also be a strategic means for a company to diversify, and/or alter focus to adapt to changing market conditions.

Most of the research in new product development has been on how to do it cheaper and faster than the next guy. However, early commercialization does not guarantee a position of strength in the market. Failures of EMI in CT scanners and Xerox in personal computers illustrate that being first to market does …

A Finite Element Simulation Of Temperature And Material Flow In Fricton Stir Welding, Mark J. Lasley

Theses and Dissertations

The purpose of this research was to use the Transvalor S.A. product, Forge3, to develop a finite element simulation of the friction stir welding process that improves the predictability of temperature evolution and material flow within the plunge portion of the process. Previous modeling created more heating within the billet than experimental results, probably due to the simplification of the simulation with adiabatic boundary conditions. More realistic tooling temperatures were included in this model as these affect heat evolution which is a determining factor in microcrystalline growth. These results were validated by experimental efforts using a billet and tooling instrumented …

A Method For Winding Advanced Composites Of Unconventional Shapes Using Continuous And Aligned Fibers, Abraham K. Allen

Theses and Dissertations

Advanced composites are extremely strong, rigid, and light, even when compared with advanced metals. Advanced composites are replacing high-tech metals as the material of choice for aerospace engineering. However, the processes used to manufacture advanced composites generally lose some of the properties of the materials by their process limitations.

One process that keeps the theoretically awesome qualities of the composite materials in tact is filament winding. Filament wound parts are used as rocket shells, bicycle frame tubes, drive shafts, pressure vessels, etc. Filament winding is an automated process and makes reliable parts to close tolerances. If a straight tube were …

Comparison Of Sampling Methods For Flatness Evaluation Using Cmm, Ashish Singhal

All-Inclusive List of Electronic Theses and Dissertations

Efficient part feature verification using Coordinate Measuring Machine (CMM) requires efficient sample point selection as well as accurate zone fitting. This work deals with flatness tolerance evaluation and the Least- Square (LS) technique is used to compute tolerance zone. In regard to the sampling strategy there are several methods commonly employed in Coordinate Measuring Machine inspection literature. The appropriate method is selected according to the accuracy requirement, the geometry features of the work piece, and the condition of the machine producing the work piece. This research focuses on the five sampling methods: Hammersley sequence sampling, Halton-Zaremba sequence sampling, Random sampling, …

The Effectiveness Of Computer-Based Tutorials In Learning Computer-Aided Design Methods For Tool Design Procedures, Andrew Moroni Hall

Theses and Dissertations

Throughout the past twenty-five years the process of designing and manufacturing a product has been revolutionized by the integration of Computer Aided Design (CAD). Although three-dimensional solid modeling, or 3-D CAD offers a better representation of the product in a virtual environment, it can be complicated and difficult to learn. Tutorials have been developed to assist manufacturing tool design student in the learning of 3-D CAD principles as they apply to tool design. This study seeks to test the effectiveness of those tutorials. A BYU tool design class was divided into two groups according to their assigned laboratory time. The …

Lead-Free Solder Joint Reliability – State Of The Art And Perspectives, Jianbiao Pan, Jyhwen Wang, David M. Shaddock

Industrial and Manufacturing Engineering

There is an increasing demand in replacing tin-lead (Sn/Pb) solders with lead-free solders in the electronics industry due to health and environmental concern. The European Union recently passed a law to ban the use of lead in electronic products. The ban will go into effect in July of 2006. The Japanese electronics industry has worked to eliminate lead from consumer electronic products for several years. Although currently there are no specific regulations banning lead in electronics devices in the United States, many companies and consortiums are working on lead-free solder initiatives including Intel, Motorola, Agilent Technologies, General Electric, Boeing, NEMI …

Work Flow Policy And Within-Worker And Between-Workers Variability In Performance, Kenneth Howard Doerr, Tali Freed, Terence R. Mitchell, Chester A. Schriesheim, Xiaohua Zhou

Industrial and Manufacturing Engineering

Work flow policies are shown to induce a change in average between-workers variability (worker heterogeneity) and within-worker variability in performance times. In a laboratory experiment, the authors measured the levels of worker heterogeneity and within-worker variability under an individual performance condition, a work sharing condition, and a fixed assignment condition. The work sharing policy increased the levels of worker heterogeneity and worker variability, whereas the fixed assignment policy decreased them. These effects, along with work flow policy main effects on mean performance times and variability are examined. This article represents an initial step in understanding effects that may be important …

The Benefit Of Using Simulation To Improve The Implementation Of Lean Manufacturing Case Study: Quick Changeovers To Allow Level Loading Of The Assembly Line, Jack J. Mcclellan

Theses and Dissertations

In today's competitive manufacturing environment, companies are constantly looking for ways to improve. Because of this, many companies are striving to become "lean" by implementing lean manufacturing, which is a difficult process. To aid in the implementation of lean manufacturing, simulation was used to reduce the trial-and-error period of lean manufacturing and find to optimum approach to implement the lean manufacturing principle. In this research, a case study of implementing level loading of the production schedule for BullFrog International, L.C. will be examined. To make it possible to implement level loading, the thermo-former machine at the beginning of the operations …

A Review Of Setup Practices And Procedures For Creating Ieee 802.11 Wireless Community Networks, Jae M. Theobald

Theses and Dissertations

IEEE 802.11 wireless networking equipment has made it possible to bridge the last mile for new broadband internet service providers. Inexpensive wireless networking equipment and high gain antennas enable high speed internet delivery at a fraction of the cost of installing or upgrading land lines for cable or DSL services. Based on this research, a guide of general practices and procedures is proposed for designing, installing, and maintaining a reliable wireless community area network. Included tests have provided performance results for several types of wireless antennas (including wire grid parabolic dishes, Yagi and Vagi styles, and echo backfire), wireless bridges, …

Development Of Image Processing Tools For Analysis Of Laser Deposition Experiments, Todd E. Sparks

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microscopical metallography is a well established field with a long history of techniques for measuring features. Modern computational power allows much more rigorous investigation than simple area fractions and intercept measurements. This paper details the development of image processing tools using GNU Octave, a free, open source numerical computation package. Proposed in the paper is a method for characterizing features within a digital microscope image.

Experimental Investigation Of Laser Metal Deposition Of Functionally Graded Copper And Steel, Vinay Kadekar, Sashikanth Prakash, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser metal deposition is an emerging technology for producing fully dense metallic parts. This process shows a promising future for the deposition of functionally graded steel - copper alloys. Good thermal conductivity of copper and a high wear resistance of steel can be achieved in dies and cores. However, to accomplish this, there are many issues to be resolved, such as the formation of an undesirable phase, solidification cracking, porosity at the interface and difference in thermal coefficient of expansion between steel and copper. The influences of process variables, such as laser power, laser scan speed, composition, powder flow rate, …

Numerical And Experimental Analysis Of The Powder Flow Streams In The Laser Aided Material Deposition Process, Yogesh D. Thakar, Heng Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Axial powder stream concentration between the nozzle end and the deposition point is an important process parameter in the laser aided material deposition process. The powder concentration is greatly influenced by the nozzle geometry in use. This paper describes the numerical and experimental analysis of this important parameter in relation to the coaxial nozzle. The experiments are performed with the different nozzle geometries to generate various flow patterns of the gravity fed powder in a cold stream. The results of the experimental analysis are compared with the numerical simulation and found justified. These results are used in concluding the significance …

Study Of Ceramic Slurries For Investment Casting With Ice Patterns, Qingbin Liu, Ming-Chuan Leu, Harish Jose, Von Richards

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Ice patterns generated by rapid freeze prototyping or a molding process can be used to make ceramic investment molds for metal castings. Due to the use of ice, the ceramic slurries must be poured around the pattern and cured at sub-freezing temperatures. Success of this process depends greatly on the mold strength after the gelation of the slurries. This paper describes the experimental results of the mold strength after the gelation of the slurries under different compositions. The parameters considered include mixing time, alumino-silicate vs. fused silica ratio, volume of binder, and volume of catalyst. The strength of the gelled …

Modeling Of The Metal Powder Flow With Carrier Gas In Coaxial Nozzle For Direct Laser Deposition Process, Heng Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In direct laser deposition process, metal powder is directly fed with carrier gas through the coaxial nozzle into the melt pool created by the laser to form the solid parts. Many operational parameters of the process depend on the characteristic of the powder stream structure below the exit of the coaxial nozzle. In this paper, a computational approach is developed for the simulation of the gas-particle flow in the coaxial nozzle. By taking into account the nozzle geometry and operating parameters, such as width and inclination angle of powder passage and carrier gas velocity, the developed computational code allows the …

Wire Bonding Challenges In Optoelectronics Packaging, Jianbiao Pan, Patrice Fraud

Industrial and Manufacturing Engineering

Wire bonding has been used in integrated circuit (IC) packaging for many years. However, there are many challenges in wire bonding for optoelectronics packaging. These challenges include bonding on sensitive devices, bonding over cavity, bonding over cantilevel leads and bonding temperature limitations. The optoelectronics package design brings another challenge, which requires wire bonding to have deep access capability. In this paper, the wire bonding technologies are reviewed and ball bonding and wedge bonding are compared. The variables that affect the wire bonding process are then discussed. Finally, the challenges of wire bonding in optoelectronics packaging are presented in detail.

Effect Of Chromium-Gold And Titanium-Titanium Nitride-Platinum-Gold Metallization On Wire/Ribbon Bondability, Jianbiao Pan, Robert M. Pafchek, Frank F. Judd, Jason Baxter

Industrial and Manufacturing Engineering

Gold metallization on wafer substrates for wire/ribbon bond applications require good bond strength to the substrate without weakening the wire/ribbon. This paper compares the ribbon bondability of Cr/Au and Ti/TiN/Pt/Au metallization systems. Both chromium and titanium are used to promote adhesion between substrates and sputtered gold films. Both can diffuse the gold surface after annealing and degrade the wire/ribbon bondability. Restoring bondability by ceric ammonium nitrate (CAN) etch was investigated. Experiments were conducted to investigate the effect of Cr/Au and Ti/TiN/Pt/Au, annealing, and CAN etch processes on 25.4 times; 254 μm (1 × 10 mil) ribbon bonding. All bonds were …