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.