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PEMM Theses
2001
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| Laura Denise, Kaegebein |
Models for Optimization of the Integration of Parts: Application
in the Aerospace industry |
| Matthew S. Lau |
A Strategy on Bill of Material for High Volume High Variability
Product Release |
| Adam Terry |
A method for determining Tool Group flexibility with Uncertain
Machine Variability: Application in a Semiconductor Manufacturing Process |
| Jesse Rehr |
Evaluation of heat transfer advantage in development of a
new electric submergible pump system |
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2000
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| Touya A. Harris |
Standard interior configuration : a process for developing
a standard selection interior and reducing engineering design time
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| Troy Harris |
A comparative simulation of advanced re-entrant scheduling
policies in a semiconductor application |
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| Bekki Leu |
Finished goods distribution strategy : a case study
of Solectron |
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| John R. Mason |
Software packaging process improvements : a case study
in the application of modern quality concepts at Microsoft |
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| Eric M. Moe |
Improving shotshell performance : an engineering and
business opportunity analysis |
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| Long K. Nguyen |
A decision support model for quality implementation
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| Welly Sugiarto |
A framework for developing and managing network security
system |
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| Shawn A. Williams |
Cooling system design for a solid state laser |
1999
|
| Garry M. Heike |
Modeling of Alternatives for Mixed Model Assembly in the Aerospace
Industry |
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| Elizabeth W. Kent |
Reducing Cycle Time in an Assembly and Test Area Using Simulation
Modeling |
| Kirk R. Neumann |
Development of a Business Strategy and Cost Model for Evaluating
a New Telecom Laser Design |
1998
|
| J. Bissell [abstract] |
Controlling Supplier Variability - An Analysis of Frame Mismatches
in the 41 Section of an Aerospace Aircraft |
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| Christoph Brem [abstract]
|
Titanium Castings in Primary Aircraft Structures - Status Quo and
Implementation Proposal |
| Robert V. Dwyer [abstract]
|
Process Optimization in Steel Platform Fabrication and Painting |
| Christopher D. Hance [abstract]
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Production Policies for Multiple Products and Multiple Product Families
|
Timothy E. Hansen
[abstract] |
Resource Allocation in the Communications Industry |
1997
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| Greg Harr, Tom Monahan, Tor Lund-Larsen [abstract] |
Feasibility Analysis of Nondestructive Inspection Methods |
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| Tom Trahan [abstract] |
A Regional Plant Site Location Decision Model for Thailand |
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| Keith Stokke [abstract] |
Improving Manufacturing Process Efficiency: A Case Study in
the Application of Modern Manufacturing Concepts
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| Kevin Roberts [abstract] |
Assembly Locations Options: A Case Study in the Electronics Industry |
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| Tim Menasveta [abstract] |
Energy Consumption and Toxics Release Patterns in the Cement Industry |
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| Eric Jacobs and
Andy Mermans [abstract] |
Ship Building: Process Improvement of Steel Fabrication
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1998
|
| J. Bissell |
Controlling Supplier Variability - An Analysis of Frame Mismatches in
the 41 Section of an Aerospace Aircraft
With the ever increasing pressures of a competitive aerospace industry,
aircraft must be manufactured quicker, cheaper, and with more quality
than ever before. In view of this fact, suppliers of parts and sub-assemblies
must be relied upon to deliver excellent product to the final assembly
process. To ensure supplier hardware variability problems that disrupt
aircraft assembly are minimized, methods of variability control must be
established and employed.
The research herein analyzes the supplier hardware variability that currently
manifests the Boeing 767 commercial aircraft program. The central focus
will be on frame mismatches occurring in the 41 section of the plane.
This problem is the catalyst from which statistical process control tools
are utilized as a means to explore methods of variability reduction. These
SPC tools also present a model that can be implemented by Boeing to control
future hardware variability problems. Besides the use of statistical methods,
customer/supplier common tooling index points will be discussed as an
approach to further reduce variability. Recommendations are then given
applicable to the 767 program in the quest to control supplier variability.
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| Christoph Brem |
Titanium Castings in Primary Aircraft Structures - Status Quo and Implementation
Proposal
Titanium castings are rarely used in primary aircraft structures. This
is due to both the required application of a casting factor, and the low
knowledge confidence of design engineers in the mechanical properties
of castings. Aviation authorities require the casting factor, actually
an additional safety factor, because of the perceived inconsistent material
properties of castings. This factor is based on the knowledge of casting
properties developed in the 1950's . While the casting factor has not
changed since then, the casting industry has. Recent test programs at
military and civil airframe and engine manufacturers have provided static
and dynamic data, especially for Ti-6A1-4V, that prove consistency in
modern foundry castings.
The purpose of this thesis is to compare the perceived versus actual quality
of titanium castings and suggest an action plan in order to realize the
potential of titanium castings. After a brief introduction to titanium
as an aircraft material, the changes in the casting process are outlined
and evaluated in terms of how they can influence the part designer's decision
making. The main benefits of castings include almost unlimited design
opportunities, and significant savings in cost and time through near net-shape
production with minimal machining. Both the high cost of titanium and
the difficulty in its machining favors castings over other production
methods, such as forgings or fabrication.
However, to eliminate the casting factor, a statistically relevant database
of material properties for titanium castings is necessary. The existing,
fragmented data available is presented, and efforts by various organizations
towards a more relevant set of data are explained. Only if design allowables
are created for use, and the confidence of design engineers in castings
is established, will it soon be possible to realize the great potential
of titanium castings.
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| Robert V. Dwyer |
Process Optimization in Steel Platform Fabrication and Painting
The platform, or lifting basket carries one or two passengers on top of
the articulated hydraulic boom of the 14,000 pound mobile man-lift--a
tool used extensively in the construction industry to allow safe and efficient
work at various heights. Unlike scaffolding, the man-lift adjusts quickly
and is easily moved. Other uses include maintenance, service, and rescue.
The finished platform is fabricated in a welding process from tubular
steel, plate steel, wire mesh, and sheet metal. The weldment is then painted
in an electrostatic powder process for color and rust protection.
The current process is single piece or small batch flow fabrication of
the platforms in parallel with other steel components that merge together
for painting. The fabrication and handling is largely manual. Machinery
used includes a band saw, tube bender, tube notcher, and welding machines.
The painting occurs on an overhead conveyor through wash, dry, coating,
and curing cycles. Once painted, the steel components merge with other
parts for final assembly.
The process allows production of about 17 platforms per day. There is
a desire to increase production for increased demand, and to accommodate
production of replacement platforms for existing lifts. Total demand is
projected at 27 units per day. This increase will be accompanied by design
changes in the platform. Previous versions of baskets have different designs
and use different parts and tooling. The fabrication process involves
multiple handling, long distances, and unnecessary storage of parts. The
platforms represent the greatest challenge to the painting process of
all steel parts, and therefore limit expansion of that process. There
is also a shortage of floor space. All information and data gathered about
the process was obtained through onsite observation, interviews, and company
documents over a period of about 2 months.
Therefore, the goal of this thesis is to optimize the production of steel
platform weldments. There are multiple and competing objectives including
process ramp-up, space limitations, cost minimization, inventory reduction,
cycle time reduction, expansion of product mix and scheduling limits.
Simulation models and optimization techniques will be applied to identify
the constraints, prioritize objectives, and model the transition into
an optimal process.
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| Christopher D. Hance |
Production Policies for Multiple Products and Multiple Product Families
Four models were presented to address optimized production cycles and batch
sizes for systems involving both product family setup costs and product
variant setup costs. Model 1 assumed production of each variant once per
cycle, and sought to minimize inventory costs associated with setups and
holding of finished-goods inventory. A closed-form solution was obtained
for cycle length, T, which could in turn be used to solve for the optimum
batch sizes of each product variant. Model 2 assumed production of each
variant once per cycle, and sought to minimize inventory costs associated
with setups and holding of finished-goods inventory - as well as the costs
incurred by intentionally backordering product variants to later production
cycles. (This was in fact a more general version of Model 1, in which backorder
costs were assumed to be infinite.) Closed-form solutions were obtained
for cycle length, T, and the fractional portion of the cycle for which backorders
were incurred, tij. Model 3 allowed variants to be produced multiple times
per cycle, and sought to minimize inventory costs associated with setups
and holding of finished-goods inventory. A closed-form solution was obtained
for cycle length, T, in terms of frequency multipliers kij. Integer programming
was then required to minimize inventory costs by optimizing each kij. In
the sample case integer programming proved difficult, and heuristics were
presented to find solutions "more optimal" than those derived
trivially from Model 1. Model 4 assumed production of each variant once
per production cycle, but relaxed the assumption of deterministic demand.
This, however, complicated assessment of holding costs and prompted an approximation
that limited the behavior of stochastic demand for which model validity
is ensured. A system of non-linear equations was obtained that related the
cycle length, T, the fill rate or service level, which is itself an integral
relation between the demand behavior and the amount of safety stock carried.
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Timothy E. Hansen
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Resource Allocation in the Communications Industry
In this thesis we consider a simulation model for a manufacturing process
within a communications equipment manufacturer. Simulation models such as
this provide managers and industrial engineers with a valuable tool to analyze
strategies, and other changes within the system vary inexpensively. As such,
use of simulation models can prevent costly mistakes. The model developed
for this thesis discusses a simulation of an entire manufacturing system.
The model was implemented with Microsoft Excel and a nonlinear integer programming
(NLIP) problem had to be solved using Excel Solver to find a solution. Solver
utilized the GRG2 algorithm code developed by Lasdon and Waren [4,5,6,7]
in addition to the branch and bound method to determine the optimal resource
allocation of internal and external resources for any given capacity at
the lowest cost to the manufacturer. A basic discussion of optimization
and nonlinear programming algorithms is presented to familiarize the reader.
A case study involving the application of the model in a software company
is also included. |
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1997
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| Greg Harr |
Feasibility Analysis of Nondestructive Inspection Methods
The fundamental goal of the project presented here was to study the current
status of nondestructive testing technologies available for quality systems
in aircraft wing production. The importance of this in relation to efficient
production systems, the need for high quality and safety, and high economic
returns in the airline industry is also discussed. The research focused
on finding a feasible and practical technology suitable to replace the existing
indirect and destructive quality assurance system for fluid tight, fatigue
rated rivets (fasteners) used in wing-box production. The team quantified
the direct cost of the current rivet interference quality system used for
inspection on the Boeing 757 wing-box and evaluated the following nondestructive
testing methods for application to the rivet interference inspection: radiography
techniques; eddy currents; ultrasonic testing; magnetic imaging and resonance
techniques; deep residual stress measurements as well as achieving statistical
process control. The evaluation of each alternative consisted of technical
research and experimentation. An inventory management plan for the acquisition
of test coupons was developed. Organizational issues at Boeing Renton facility
related to the problem of rivet quality control and technology development
are discussed. |
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| Tom Trahan |
A Regional Plant Site Location Decision Model for Thailand
Foreign companies find Thailand an attractive location for plant site locations
as evidenced by the numerous plants established over the past decade. The
managers of these companies, however, had faced a relatively simple decision
since most industrial development in Thailand had concentrated in the Bangkok
Metropolitan Region. With recent infrastructure development in the outlying
provinces and rising costs in Bangkok due to overcrowding, managers no longer
face such an easy decision. As such, this thesis develops a decision model
that helps companies identify the most satisfactory region within Thailand
to locate their operations. The model attempts to achieve a balance between
quantitative analysis and subjective decision-making in the plant site location
decision. |
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| Keith Stokke |
Improving Manufacturing Process Efficiency: A Case Study in the Application
of Modern Manufacturing Concepts
Modern manufacturing concepts are about how to use production operations
to improve profitability while reducing waste and meeting customer expectations.
Many of these concepts originated in Japan and were brought to the United
States and built upon in the early 1980s. This paper will demonstrate
these principles by using them to analyze an actual manufacturing firm.
The subject is a company anonymously called HVAC Corporation (HC) which
is a relatively high-volume manufacturer of heaters and air-conditioners
for truck and related vehicles. HC has a primary goal to reduce throughput
time and a secondary goal to reduce inventories. Both of these are main
goals for many of the modern manufacturing philosophies.
Several issues are identified which contribute to the long lead times
and high inventories experienced by HC. Specific analyses are made of
the product flow, inventory levels, and assembly line flow. Problems identified
and potential solutions are identified based on research gathered at HC
and supported in part by engineering and manufacturing management literature.
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| Kevin Roberts
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Assembly Locations Options: A Case Study in the Electronics Industry
Companies faced with manufacturing or assembly capacity constraints can
consider several options to alleviate this problem. An obvious solution
is to add additional manufacturing capacity to the existing facility. This
option may not be feasible if space is not available for expansion. Similarly,
in a tight labor market additional manufacturing capacity will not help
if workers with the necessary skills are difficult to find. In such cases
the company must look at other options to gain manufacturing capacity. Options
include outsourcing, acquiring manufacturing capacity from another company
or constructing a new assembly plant elsewhere.
This paper examines the new assembly plant site selection process and applies
the process to Intermec Corporation, a company that is seeking solutions
to assembly capacity constraints. We specifically look at a product that
is assembled at Intermec's Everett, Washington facility and develop a decision
process for selecting an alternative assembly location for the product. |
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| Tim Menasveta
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Energy Consumption and Toxics Release Patterns in the Cement Industry
This study describes consumption patterns in the US cement industry.
Both generic end-use and process-step energy consumption models are developed
based on the Manufacturing Energy Consumption Survey (MECS) of 1994. This
study also describes the development of a similar model for characterizing
toxic chemical releases from the cement industry. The suitability and feasibility
of this latter model is discussed. |
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| Eric Jacobs and
Andy Mermans
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Ship Building: Process Improvement of Steel Fabrication
Todd Pacific Shipyards Corporation is a mature shipbuilding company
that performs both new construction and repair. Their sub-assembly shop
fabricates steel parts and sub-assemblies for shipbuilding. This study
evaluates the sub-assembly shop, with the intent of identifying process
improvement opportunities and recommending solutions. To accomplish this
the shop's products were identified and ranked. The shop's processes were
identified with flow charts. Using this data the sub-assembly shop's operation
was benchmarked against current ideas in planning, scheduling and control.
As the result of this study, six areas of opportunity were identified.
The most significant of these is related to information flow to shop personnel.
By improving the information provided to the operators the authors believe
that work in progress inventory can be reduced and shop efficiency improved.
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