Integrated
Product, Process and Enterprise Design[1]
Prepared for Computer Integrated Manufacturing (56:231)
1. Integrated product, process
and enterprise design: why, what and how?
Change is an important part
of the manufacturing industry’s future.
Change brings opportunities and threats.
Changes have everything to do with the abilities to recognize change and
emerging trends and to positively respond to them. The new business paradigm is integrated
product, process and enterprise design (IPPED).
The concept of IPPED is relatively simple. as one designs a product, in addition to
functionality and performance, other life cycle attributes, e.g.,
manufacturability, assemblability, ease of use, maintainability and
recyclability, are also considered concurrently. Product data exchange takes place
unambiguously among various applications, e.g.,
using the STEP standard.
2. Developing customer-focused
new product concepts
The economic success of firms
depends on their ability to identify customer needs and to profitably develop
and market products that meet those needs.
Careful market research and data analysis can lead to creative insights
into customer needs and wants that can lead to superior products, while
carelessness at (the early stages of design) can result in lost opportunities
and possibly outright errors in product design.
One of the most critical steps in product concept development is
conducting research to identify customer needs and to understand how current
and potential products will be positioned with respect to each other in meeting
those needs. Quality function deployment
(QFD) employs an organizing framework to identify critical customer attributes
and link customer need attributes and design parameters. Criteria are used to evaluate product
concepts to determine their market potential and response to customer needs.
3. An information architecture
for integrating real-time process control into enterprise management
Enterprise information
management in significant organizations can be overwhelmingly complex . . .
multiple data and knowledge systems operating over non-standard wide-area
networks, over 1000 databases running at a scale of over a million transactions
per day; interoperability issues and distributed updates; rapid changes in its
underlying technology, business processes and applications. A new scope of integration is to combine
applications ranging from lean embedded systems in real-time process control. A real-time rule-oriented programming
environment (RT ROPE) extends the metadatabase model for enterprise information
management problems that include real-time process control systems as well as
databases. The new metadatabase
technology incorporates existing databases and computing systems to manage and
facilitate the flow of information across an enterprise without imposing a
rigid supercontroller on all functions.
4. Quality function deployment:
optimizing product design
Quality function deployment (QFD) is a process that stresses cross-functional integration and ensures quality through each stage of the product development and production process. QFD translates needs of customers through various stages of product planning, engineering, and manufacturing into a final product (or service). Various fuzzy, multiobjective models are developed to permit a designer to consider trade-offs among conflicting customer attributes as well as inherent fuzziness in the system, and then to choose target values under various situations. A QFD optimizer has been developed to implement the modeling approach, help the design team build a ‘house of quality’ chart and determine the target engineering characteristic values that result in improved, feasible designs.
5. On process tolerance: a brief
review and models
The paper presents a brief
summary of the literature in the area of tolerance, focusing on analysis,
allocation, cost and computer integration, and introduces models for part
tolerancing that consider also the economics of reworking costs. Tolerance and part variance are not the same
thing; although part tolerance may be expressed as a multiple of standard
deviation. Cost of tolerance, usually a
function of design and machining costs, is defined as the amount of expenditure
needed to achieve certain levels of dimensional and geometrical accuracy.
6. Design for reliability in
concurrent engineering
To assist unskilled designers
in product modeling from the viewpoint of reliability, a concurrent processing
approach is developed that uses the concept of intelligent design
observer. For concurrent processing to work,
integrated tasks need to be decomposed into subproblems. The method enables the designer to obtain
reliability information at any time during product modeling, find malfunctions
before models are completed, evaluate the effect of design changes, and reduce
the time consumed in design tasks.
7. Quality engineering
The philosophies and
techniques behind the movement toward creating a total quality organization are
reviewed. Quality cost systems
constitute important tools for measuring the performance of any system, and
perhaps more importantly, identifying opportunities for improvement. Benchmarking performance against competitors
provides feedback on necessary and potential areas for improvement. Quality function deployment (QFD) can be used
to achieve quality and performance objectives through customer-driven product
design and system operation. Designed
experiments can play an important role in planning, developing, optimizing and
improving products, processes and services.
Measurement systems are used to monitor quality and provide information
for maintaining process control.
8. Rapid prototyping and
freeform fabrication
Rapid prototyping (RP)
technologies offer a way to reduce the time and cost associated with product
development. There are many terms used
to describe the technology and many different types of available
processes. In addition to the time and
cost considerations, dimensional accuracy, surface texture and material
properties must be evaluated. Many
applications for RP systems have been developed during the past ten years. Prototypes can be used (from some processes)
for functional testing, process tooling, biomedical implants, and
microfabrication applications. Companies
have the option of acquiring RP systems or having service bureaus make the
prototypes for them.
9. Assemblability evaluation
using fuzzy inference
Today’s product development
environment involves the application of advanced mathematical methods to help
engineers work concurrently to evaluate trade-offs between design alternatives
and related manufacturing issues, while providing lower cost and higher quality
products. The decision making process in
product design often involves uncertainties and ambiguities. The fuzzy set approach provides an
approximate, yet effective and flexible means to describe the behavior of
systems that are normally too complex or too ill-defined to admit precise
mathematical analysis by conventional methods and tools. The methodology of assemblability inference
is proposed to evaluate product design decisions and determine design
improvements that can lead to better designs.
10. Computer-aided assembly
planning
The assembly process is a series of tasks putting together a set of components to produce an end product. Assembly planning is the process of preparing detailed sets of instructions to assemble a product. The paper presents a survey of research issues and different approaches to computer-aided assembly planning. Network graph representation and its versions have been most widely explored, and used for automatic assembly sequence generation, but most require a human to read the assembly design and develop the graph representation.
11. Process control
Process control, which is the
control function whose objective is to prevent production of defective units
during the production phase, is one of the important components of a quality
system. The paper focuses on methods of
producing quality products through controlling process parameters at consistent
levels, primarily the charting methods that are used as part of statistical
process control (SPC) systems.
12. Integration of process
planning and production scheduling: overview, analysis and object-oriented
modeling
In the manufacturing
industry, process planning plays a role in determining detailed procedures by
which workpieces or parts are converted from the initial stage (raw material
form) to the finished stage (desired form).
Production scheduling, or production planning and control, which strives
for the optimal use of available resources, is another important manufacturing
function in manufacturing systems. While
much work has been done to integrate the process planning and production
scheduling functions, several research opportunities exist: further development
of existing models to be consistent with real manufacturing settings;
examination of various integration philosophies, algorithms and data
structures; expanded process modeling; and implementation of current information
technology, especially those that are object-oriented.
13. Manufacturing systems
design: a review of state-of-the-art methodologies
A manufacturing system is key
to efficient and effective coordination of resources, and is especially
critical to the quality of products and services. Historically, manufacturing systems are built
with heavy dependence on empirical experience.
The paper reviews the current methodologies and tools that designers use
throughout the design process. None of
the stand-alone systems can satisfy the function of the manufacturing
system. Because each existing system has
its own operation and design, and are usually not compatible, integration of
existing systems is difficult. Several
research issues exist: development of effective integration framework;
development of a mechanism to integrate existing models; improved simulation
techniques for large scale, complex problems; and design principles that ensure
an acceptable design solution (considering both engineering and business
issues).
14. System modeling and
simulation
In order for companies to
develop integrated strategies for designing new products or re-designing
existing products, there is a need for systems modeling and simulation tools
that can support all aspects of the design of products, processes and
enterprises. Systems modeling tools
include process flow diagrams, data flow diagrams (e.g., IDEF) and other
techniques that support the IPPED process.
Simulation tools include general purpose and specialized simulation
languages, simulation front-ends and simulators. Models capture the elements and behavior of a
design and manufacturing system in a format that can be easily understood and
used to evaluate performance and cost trade-offs.
15. Evaluation and optimization
of manufacturing systems reliability
The trade-offs between
reliability and performance of a manufacturing system are often subtle. The performance of a system often increases
at the expense of increased system complexity.
With increased complexity, the system reliability might decrease unless
some compensating measures are taken.
The paper describes a reliability network representation and reduction
approach for evaluating the system trade-offs.
Ways to improve reliability, subject to cost and space constraints, are
also examined.
[1] Integrated Product, Process and Enterprise Design, edited by Ben Wang, Chapman & Hall, London, 1997.