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Page 12 1 Vision and Recommended Areas of Research Introduction The manufacturing sector is the crucible in which many technologies are refined and fused for the purpose of making things that people need or want. In 1993 manufacturing accounted for 18 percent of the $6.4 trillion gross domestic product and for nearly 18 million jobs in the United States (U.S. Department of Commerce, 1994; Council of Economic Advisors, 1994). Broadly defined, manufacturing includes all of the activities involved in determining the needs of potential customers, conceiving and producing products to meet those needs, and marketing and delivering those products to the ultimate customer. Money is made and needs are satisfied by meeting quality, cost, performance, and time-to-market goals for the product being manufactured. These attributesquality, cost, performance, and time to marketmay be taken to be the yardsticks against which any new advance must be measured. Given that U.S. leadership in certain areas of manufacturing is no longer the rule, it is reasonable to ask what needs to be done to regain international leadership in manufacturing. Suggestions abound, but in the absence of a clear strategy in this area, federal decision makers have struggled to find the right mix of investment in manufacturing research. This quandary has extended beyond the funding agencies to the universities and to academic research. There are few departments of manufacturing at U.S. universities because many academics do not believe that manufacturing is an academic discipline. Moreover, the disciplines basic to making progress in manufacturing belong not only in the "hard" sciences and engineering in physics,
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Page 13 mathematics, mechanical and electrical engineering, industrial engineering, computer science and engineering, chemistry, and materials science but also in the "softer" sciences of sociology, psychology, management science, and economics. Even though these separate disciplines are individually supported by funding agencies and universities, there is a lack of focused attention on how to integrate basic knowledge from many disciplines into knowledge that furthers manufacturing goals. Information Technology and the Increasing Complexity of Manufacturing At the same time that this lack of strategy is apparent, all dimensions of manufacturing (e.g., products, markets, processes) are becoming more complex, diverse, and international. Indeed, common products such as automobiles can have thousands of parts, and modern aircraft and integrated circuits include millions of parts or active elements. Each of these products takes years to design, requiring the effort of hundreds or even thousands of people worldwide. Complex new products based on information content and their accompanying information-dominated design and manufacturing methods already require us to deal with entirely new scales of complexity.1 Some products require such levels of precision, delicacy, or cleanliness that people can no longer make or assemble the parts; in some cases, they cannot even see them. To realize these and other products, manufacturing firms must cope with design processes (e.g., converting customer requirements and expectations into engineering specifications, converting specifications into subsystems), production processes (e.g., moving materials, converting material properties or shapes, assembling products or subsystems, verifying process results), and business practices (e.g., converting a customer order into a list of required parts, cost accounting, and documentation of procedures). The illustration on the cover indicates the relationships among these various elements of manufacturing and the role of information technology (IT; Box 1.1) in integrating them (see also Figure 1.1). By providing ways to facilitate and manage the complexity of these information-intensive processes, as well as to achieve integration of manufacturing activities within and among manufacturing enterprises, information technology will play an increasingly indispensable role in supporting and even enabling the complex 1 A case in point is very large scale integrated (VLSI) chips. A single VLSI chip may have several million transistors with submicron feature sizes. A complex system may have hundreds of chips and tens of millions of transistors. Logic design, functional tests, fault tests, timing, placement, and wiring data run to gigabytes per chip. Validation of a design may involve many millions of simulated test cases. Finally, different aspects of chip design are coupled, so that changes required in the logic design (for example) often affect the analysis of derived fault, timing, and place and wire views of the logic. Similar observations apply to airplanes, ships, and cars.
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Page 14 BOX 1.1 Information Technology for ManufacturingDefinition and Elements Although there are many definitions of information technology (IT), this report defines IT as encompassing a wide range of computer and communications technologies. IT includes the hardware that computes and communicates; the software that provides data, knowledge, and information while at the same time controlling the hardware; and the robots, machinery, sensors, and actuators or effectors that serve as the interface between computers and the outside world, specifically the manufacturing shop floor. Note also that the effective use of information technologies demands considerable investment in training and maintenance. Examples of IT include the following: •Computers Workstation Mainframe Server Personal digital assistant •Communications devices and infrastructure Telephone Local area network Wide area network Wireless network •Software Operating system Artificial intelligence expert system for product configuration Computer-assisted design package Animation and simulation software Virtual reality simulations Software for total quality management and inventory control Scheduling package •Sensors Machine vision Tactile and force sensors Temperature sensors Pressure sensors •Actuators or effectors Robot arm Automated ground vehicle Numerically controlled cutter Microactuators Information technologies are focusing to an increasing degree on knowledge and information rather than data alone. That is, advances in information technologies over the last 40 years have enabled the manipulation and processing of increasingly abstract and higher-level forms of information. For example, industries cannot rely only on postmortem quality control data to detect product defects: modern quality assurance requires that potential problems be traced back through the manufacturing system for high-level analysis at each manufacturing unit. IT that is used in support of such an approach depends as much on knowledge and diagnosis as on simple data gathering.
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Page 15 FIGURE 1.1 Information technology as a means to integrate various basic manufacturing activities. practice of manufacturing. In the decades to come, information technology may have an impact on manufacturing performance and productivity comparable to that of mass production. Purpose, Scope, and Content of This Report This study was conducted to identify areas of information technology-related research needed to support future manufacturing. The committee chose to define manufacturing broadly as the entire product realization process, from specification through design and production to marketing and distribution. Although it believes that information technology has important applications to both continuous and discrete manufacturing, the committee focused on discrete manufacturing as the type in which the problems of applying information technology are most pressing. It did not include in its deliberations such important dimensions of manufacturing as the study of physical processes in manufacturing, although it did address information technology as it might be applied to controlling these processes.
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Page 16 Chapter 1 of this report outlines some of the technical and other challenges confronting the manufacturing enterprise at the outset of the 21st century, expresses a vision of future manufacturing based on what is known today and what might be expected from information technology-related R&D efforts in the future, and recommends a research agenda aimed at achieving this vision. Chapters 2 through 7 elaborate on the contents of Chapter 1. Chapter 2 presents the context for manufacturing. The R&D agenda implied by the vision of Chapter 1 is the subject of Chapters 3 (product and process design), 4 (shop floor production), 5 (factory modeling and simulation), 6 (information infrastructure issues), and 7 (nontechnology issues). Chapters 3 through 7 explore in more detail the research questions that must be answered successfully if the vision of a robust and internationally competitive 21st-century manufacturing enterprise is to be achieved. A list of contributors to the report, a description of an engine plant visited by the committee, and sketches of possible advanced long-range technology demonstrations are given in Appendixes A, B, and C, respectively. Flexibility For The Future In the manufacturing environment of the 21st century, several trends will place increasing pressure on manufacturers: • Larger numbers of product variants will be required to meet user demands for greater product customization. This will lead to pressures to reduce production lot sizes while maintaining unit costs at an economic level. Manufacturers will need production facilities that are economic and profitable at very low volumes and that have low "fixed" costs. • Increasing dispersion of manufacturing operations is likely. Successful manufacturing companies will be forced to develop effective global manufacturing networks, "knitting together" the skills and capabilities of individual units located around the globe to create a seamless international production capability; organizationally, the factory floor will see self-directed work teams "managing" the day-to-day operations of the firm with minimal real-time supervision, with white-collar labor focusing much more on the creation of new and improved products. These trends will almost certainly lead to a reduction in the average size of manufacturing facilities, the increasing use of "temporary" assets (via leasing or other cost-sharing arrangements), and the development of common processes so that manufacturing activities can be moved rapidly to locations that need increased production. • Shorter time to market will become even more important than it is today. One aspect of this issue will be the ability to deploy technology rapidly. Another will be the ability to execute customer orders rapidly. Manufacturing concerns will emphasize work force skills and empowerment in order to meet marketplace needs for speed.
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Page 17 • Global environmental concerns seem certain to motivate the development of ''green" and recyclable products and manufacturing systems that use fewer material resources.2 Manufacturing systems should be able to accept "used" products that they have fabricated, disassemble the received items into component parts, and determine which parts are reusable or which are convertible into recyclable raw material with the ultimate goal of a product that leads to zero scrap material. Of course, products will need to be designed with such goals in mind. Responding to these challenges will require unprecedented flexibility. Flexibility in manufacturing is associated with rapid responses at the appropriate level to new information and constraints, which may range from changes in consumer preferences or international trade regulations or union requirements to a temporary fault in a crucial piece of machinery on the factory floor. Whatever the source of change or constraint, information systems in the factory must enable an appropriate response. Information technology will enable better planning and organization as well, helping to control the events to which responses are needed. Recognizing Information Technology's Increasing Capability in a Changing World The role of information technology in manufacturing can be seen in the increasing use of computers to underpin product design and fabrication processes and to support related business processes such as sales and distribution. To date, the primary uses of information technology in manufacturing have been to control machinery and tools on the shop floor, to assist with administration in areas such as accounting and bookkeeping, to speed the transfer of information, and to support the management of product and process complexity (e.g., through computer-aided design (CAD) or manufacturing resources planning). Table 1.1 compares past and present characteristics and roles of IT in manufacturing. Although these roles will continue to be important, the committee believes that information technology will become an increasingly significant source of support for different types of decision making needed in manufacturing (Box 1.2). This belief in the benefits of information technology is based on three premises: 2A recent agreement between two European auto manufacturers establishes a recycling network aimed at decreasing waste. It has begun to increase awareness of the importance of creating environmentally correct products for sustainable development around the world. In other cases, the producers of tires and batteries have been challenged to produce a product that can be disposed of without landfills. Taxes have been imposed on the purchase of new batteries and tries to help offset the cost of disposal. Yet such efforts are still the exception given the scope of manufacturing worldwide.
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Page 18 TABLE 1.1 Past and Present Information Technologies and Their Roles in Devices and Activities Integral to Manufacturing Past Present Information Technology Computing platform Mainframe computers Personal computers and workstations for most computing Databases Mostly paper records, stored in file cabinets Large amounts of business data resident on electronically searchable, remotely accessible databases Information retrieval Human information specialists (e.g., public and private librarians and corporate information expediters) Database retrieval systems now the basis for managing complex problems involving more subassemblies and more interactions with suppliers Data communication 300 bits per second; hence, major restrictions on the size, complexity, and usefulness of the items communicated 1 to 10 megabits per second, often carried over local or wide area networks. Hence, large models (e.g., aircraft or automobile bodies) sent quickly, permitting designers states or continents apart to collaborate more easily Manufacturing Technology Sensors Mostly analog Heavily digital Recording media Chart recorders Computer-readable media Control logic and machine controller Mostly classical control theory (as exemplified by the proportional-integral-derivative controller); machine controllers using many subsystems based on programmable logic controllers Classical control theory still used; modern control theory (state space analysis), fuzzy logic, and neural network controllers more common
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Page 19 TABLE 1.1 Continued Past Present Control systems Analog amplifiers, electromechanical relays, and pneumatic and hydraulic actuators; automated machining operations performed using APT programming that generated cutter location data (CLData) on paper tape Personal computers. Paper tape largely replaced by computer-controlled machines operating on CLData; data sometimes received through a computer network. Programmable technology enabling faster and more accurate control, with the end result that much more complex parts can be made much more quickly Engineering Practice Analysis Relatively minimal; manual processes; based largely on past practiceknowledge of what did and did not work in the past Extensive and computer-supported to a large degree (computer-aided design to represent solid geometry of parts and assemblies, kinematic motions of parts, and some of the machinery used to make and assemble them); computer-aided engineering models of mechanical parts and assemblies used to simulate kinematic analysis Design for product variety Products largely standard, with few options for buyers Higher degree of variety and customization possible Product testing Exhaustive testing of physical models Computerized simulation and engineering analysis as substitutes for much physical testing; physical testing now used primarily as a final verification of design Engineering style "Over-the-wall" engineering, with market research, product design, and production working in isolation Concurrent engineering (working on requirements, design, and production simultaneously) increasingly recognized as important and slowly becoming a common organizational objective, although not by any means the norm today Problem resolution Long face-to-face meetings between participants to address problems requiring attention by more than one department in a company Electronic conferences, either by telephone alone or with video support, to address problems; meetings and meeting overhead thus reduced continues
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Page 20 TABLE 1.1 Continued Past Present Production Operations Product data recording and use Almost entirely paper records and engineering drawings Electronic form for many types (especially for product or component shape and geometry) Scheduling philosophy Scheduling to maximize the use of (expensive) machines and people and to maximize work in process (WIP) Scheduling to balance high levels of machine and personnel use and low levels of inventory (minimizing WIP) Contingency management Scheduling software task-oriented and not responsive to contingencies: software told what was to be done, and the human operator was expected to carry out the task Software giving many shop floor personnel access to constantly updated information on status of machines, location of breakdowns, and schedule realization Relationship between product engineering and product release Systems completely separate and functioned nonconcurrently Systems still separate, but operating concurrently Information flow Paper traveled with the product through assembly lines In many factories, bar-code identification of parts moving through production that keep track of their positions and tell machinery which steps to perform; bar codes, coupled with digital status keeping, often used to develop systems that minimize "guess work" on inventory levels and improve use of assets • Information technology will facilitate appropriate reuse of knowledge (e.g., reusing the design of a previously produced part rather than designing a new one from scratch), thus enabling decision makers to build on precedents and past decisions that have subsequently been validated by experience. • Information technology will enable a high degree of integration among the various processes of manufacturing: product design and process design, shop
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Page 21 BOX 1.2 Needs of Manufacturing Decision Makers and Examples of How Information Technology Could Contribute to Meeting Them Need Example of Information Technology's Contribution Situational awareness. Both white-collar and blue-collar personnel must be informed about events in the manufacturing environment. An unexpected event may be anything from the breakage of a tool or the delay of a shipment to a design change made to a product. To promote and enhance situational awareness, an IT-based factory information system could display the status of various tools and machines on the shop floor. Diagnosis of problems. Decision makers need to identify the nature and extent of problems. Unexpected events can have a variety of causes. For example, a tool may cease functioning because it blew a fuse, because the bit broke, or because the motor seized due to a lack of lubrication. The stoppage could also have been the result of another error or problem somewhere else on the shop floor. Knowing what caused the problem is key to fixing it. To assist in problem solving, diagnostics aboard a tool could be transmitted to a shop steward in real time. Analytical tools. Decision makers need to evaluate and test various problem-solving approaches and strategies. For example, a decision maker may need to choose between allowing a cell to operate at reduced speed (lowering the throughput but also the risk of damage) or operating it at full speed (increasing the likelihood that the tool will have to be shut down entirely for repairs). To enhance analytical capabilities, information technology-based simulations could help factory managers understand the consequences of different courses of action. Dissemination channels. Solutions to problems must be disseminated. For example, information about the appropriate speed choice for the tool described above is needed both by the on-site crew and by the machine's manufacturer. To enable timely dissemination of solutions to problems, information technology networks can be used to provide relevant text and graphics to all affected sites.
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Page 22 floor operations, and business practices, thereby increasing the ease with which a product can be brought to market and reducing costs. • Information technology will increase the opportunity for human decision makers to think about the products and processes of manufacturing in abstract, higher-level terms without focusing on lower-level and repetitive details, thereby increasing the speed with which decisions can be made and implemented and improving the quality of those decisions. This premise is perhaps the most controversial of the three. These premises have been articulated and tested before, with varying degrees of success. What is it that gives rise to the committee's belief that information technology will be the basis of the next paradigm shift in manufacturing and a source of enhanced productivity? The most straightforward answer is that the world has changed. The cost-performance relationship for information technology has improved so much over the last decade that it now seems feasible to devote many more computational resources to problem areas that were previously starved for such resources. More importantly, social and technological factors relevant to the successful implementation of IT in manufacturing are now much better understood. Concerted attention to these factors will dramatically improve the prospects for using IT successfully in manufacturing in the future. For example: • Socially, the culture of manufacturing is, for many good reasons, highly conservative, whereas IT is an enabler and facilitator of radical change (although such changes may take place over time). Moreover, although manufacturing is hundreds of years old, computers have been available for use in factories for only about 40 years and thus have not yet been fully integrated into the factory. (Social dimensions of the resistance to IT are addressed further in Chapter 7.) • Technologically, early ventures in applying IT to manufacturing reached too far too fast. In contrast to the Japanese approach that blended IT applications in manufacturing with existing work forces, the U.S. approach was capital-intensive and tended to downplay operations and maintenance issues. In addition, the success of IT in many individual aspects of manufacturing has not been reflected in the integration of these applications into a smoothly running system, and such integration has been (and continues to be) quite difficult. In the absence of integration, it is difficult or impossible for different computer manufacturing applications to exchange information, and the result may be as cumbersome as having no automation at all (Box 1.3 describes a not-atypical experience in today's factories).
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Page 38 A programmable factory is also necessary for the economic manufacture of highly customized products. An example from today is the ''on-demand" production of soft-cover textbooks in which chapters can be selected by a teacher based on his or her individual teaching needs. With increased product customization, customers would be able to obtain catalog items with the features, characteristics, and aesthetics they desired, at prices they could afford (probably comparable to the prices for mass-produced goods). The material and manufacturing cost per unit of producing a product likely would not be significantly different for a production run of 100 units or of 100,000 units in a single batch. Smaller lot sizes would also have major benefits with respect to quality control. When defects in a production process are caught early (as is the case when small lot sizes are produced), the amount of rework is minimized and fixes to the production process can be implemented more rapidly. Note that high degrees of customization create additional stresses on scheduling. Since customization requires only small quantities of specialized materials, "just-in-time" scheduling either works properly or fails by idling the production machinery; the option of building inventory as a hedge against missed delivery times simply does not exist, since maintaining excess inventory is then a matter of purchasing unnecessary components rather than purchasing components that will ultimately be used. The Networked Factory In concept, a networked factory is one in which suppliers (both internal and external) and customers are connected electronically to a manufacturer (e.g., on the National Information Infrastructure). Manufacturers have been tied to suppliers and customers by telephone, mail, telex, and fax for years; the primary advantage of electronically networked connections would be the speed with which information could be exchanged and processed, sometimes automatically by intelligent agents that could respond to certain routine requests. An electronically networked factory (hereafter a networked factory) would demonstrate significantly reduced transaction times as information technology reduced the delays of paper-based information transfer; information technology would facilitate instantaneous acknowledgement, scheduling of deliveries, and guaranteed service times. Many of the factors contributing to delays in the design and production processes would be significantly reduced within a networked factory. Reducing delay would contribute to reducing the time to market for new or improved products. A particularly important improvement would be a reduction of the time it takes a production facility to initiate the first step needed to respond to an order, since it is this time that often dominates the overall time required to fill an order. Enabled through the National Information Infrastructure, networked factories would increase the options available to product and process designers.
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Page 39 Today's designers are strongly constrained by the process capabilities of manufacturersproduct designers do not design products that their factories cannot make, and process designers do not create processes that their factories cannot implement. Indeed, even approaches to design regarded today as sophisticated (e.g., design for manufacturability, design for assembly) are necessarily limited by preexisting production processes and facilities. When a single firm owns the means of production, such approaches make sense. But if constraints on ownership are relaxed (and process elements consequently can be linked on a regional, national, or even international basis), designers can be freed to focus primarily on the expressed needs of the customer without worrying about how best to use a single plant for which many costs have already been incurred. Designers using a networked factory would be able to "outsource" various production processes more easily and to coordinate their operation. Of all the different modern concepts in manufacturing, the idea of a networked enterprise including a networked factory is perhaps the most widely accepted and adopted; in some circles, the term "agile manufacturing" is also used. Further, the evolving National Information Infrastructure is expected to facilitate networking of all sorts. Chapter 6 discusses this connection in greater detail. Microfactories A microfactory is a production facility whose output capacity can be scaled up by the replication of identical facilities. Since microfactories would not depend on economies of scale for economic viability, they would draw strongly on the technologies of programmable or reconfigurable factories as they attempted to produce small-scale output at unit costs comparable to or only slightly higher than those for mass-produced items. If microfactories prove to be feasible, a single, large, centralized manufacturing facility could be replaced by a large number of replicated, modular microfactories that could be geographically distributed and located close to customers. For producing quantities of identical items, traditional factories oriented toward mass production will probably remain superior to microfactories, because anything that could be done to improve the production process in a microfactory could also be done in a traditional factory. On the other hand, today's mass-production factories are capital-intensive construction projects that are themselves custom-built. If a microfactory could itself be mass produced in quantities large enough to reduce the cost of an individual microfactory, it might be possible to amortize the cost of designing the microfactory over many such (identical) facilities. Even today, some steel micromills have drastically reduced the capital cost of steel production. In addition, microfactories might incur lower product transportation costs (as the result of placing microfactories near customers), lower
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Page 40 inventory costs (as the result of production on demand), or lower labor costs (as the result of using locally available labor). Irrespective of cost issues, however, microfactories might well provide advantages in other situations. For example, microfactories might provide a way for firms to insert local content into manufactured products, perhaps through local final assemblya capability that could be desirable for political purposes (e.g., as a dimension of international trade relationships). A second example of a microfactory could be a mobile fabrication facility (e.g., a microfactory located on a large naval ship that produces replacement parts for the battle group with which it sails); in such a scenario, economic concerns might be secondary to the capability for a rapid response. A third example is that microfactories of a sort do exist today, although they make business sense for reasons other than lower unit production costs. Microbreweries for beer and street-corner copy shops are two examples of microfactories in which production costs are higher than those of larger facilities; nevertheless, such microfactories fill niches because they provide higher quality or greater convenience. The primary challenge remaining for microfactories is one of economics. Getting From Here To There The Need For Balance And A Considered Approach The various new manufacturing capabilities described above are tantalizing and appeal to many current notions of the progress possible in manufacturing. But for this vision to be realized, it will be necessary first to balance the responsibilities of factory managers and manufacturing decision makers to turn out quality products at low cost in a timely manner today against the desirability of planning to secure the potentially large improvements offered by judicious and innovative use of current and future information technology. Even if these tensions are resolved, however, the full implications of successfully implementing IT are not known, and neither the committee nor the manufacturing community at large has thought through the many possible effects. To illustrate, success in some of the areas discussed above raises the following questions: • If products are available on a fully customized basis, what happens to service, repair, and maintenance? Technicians may be faced with an extraordinary learning task if they are to be competent at repairing thousands of customized variations, although such a task might be mitigated by electronic information carried aboard the product itself. In locations far removed from production facilities, cannibalization of one unit to obtain spare parts for another is a time-honored maintenance practice that may no longer be feasible. Even today, documentation of new products for maintenance and repair technicians is an enormous problemhow will documentation be provided for an even larger number of
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Page 41 products? Will information technology provide solutions to this problem, or will new approaches to product design reduce the need for voluminous documentation? • What are the limits (if any) to desires for novelty and customization? Customers may not all want entirely customized products. Consider, for example, automobiles whose control systems (e.g., steering wheels, clutches) are entirely different; such differences might even prove detrimental to public safety. Cost pressures may limit the variety that consumers are willing to purchase. Customers may also resist products that demand that they learn new habits and operating procedures. Finally, customers may not even know what they want with the precision needed to specify a customized product. • If automation replaces multitudes of manufacturing workers, what becomes of the displaced workers? Will they become managers? Technicians? Who will retrain them? For what will they be retrained? How will manufacturing workers in the new regime respond to being directed by automated overseers? • If manufacturing operations are dispersed geographically, what becomes of team and corporate loyalties that are often the result of physical proximity and informal day-to-day social contact through work? What will happen to geographically based brand-name and corporate loyalties? • What degree of information automation is "right"? In the case of physical automation, trying to automate many factories entirely proved to be a poor choice; improvements in productivity were obtained at the expense of flexibility, and it turned out that flexibility was a much more important characteristic. This may also be so in information management; what degree of automated decision making is appropriate? This is a very subjective decision, differing for different industries. • How will research results, such as new fabrication processes, be converted into economical and reliable factory equipment? The same question applies to the conversion of new design algorithms into easy-to-learn CAD software. The industries that supply these vital infrastructure elements are short of technical expertise, financially weak, and subject to huge fluctuations in demand. • How will the sophisticated ideas outlined in the committee's vision of future manufacturing be transferred to small businesses and lower-tier suppliers? Large businesses depend crucially on the lower tiers, but many businesses in these lower tiers may not be able to compete successfully without new technologies or assistance in adopting these technologies. These questions, and many others, are largely outside the scope of this report. But their identification, articulation, and eventual resolution are an integral part of moving toward a vision of IT-enhanced 21st-century manufacturing. Whatever one's view, it is clear that a number of major technological and sociological barriers must be overcome before IT's potential to revolutionize manufacturing can be widely accepted and achieved. More rapid progress in
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Page 42 overcoming these barriers will increase the likelihood of earlier acceptance and achievement. The nature of these challenges and the research needed to overcome them are the subjects of the next several chapters. The Research Agenda Technology Research In formulating a research agenda, the committee was faced with the realization that manufacturing is fundamentally a complex activity, with many interactions among its various components. In the committee's view, this realization reflects the nature of manufacturing as "an indivisible, monolithic activity, incredibly diverse and complex in its fine detail … [whose] many parts are inextricably interdependent and interconnected, so that no part may be safely separated from the rest and treated in isolation, without an adverse impact on the remainder and thus on the whole" (Harrington, 1984). Thus, it is fruitless to seek the identification of specific "silver bullets" upon which all other progress in the field depends. That said, however, the committee has identified several general themes for technology research that would advance the capabilities of information technology to serve manufacturing needs; these themes include product and process design, shop floor control, modeling and simulation ("virtual factory") technology, and enterprise integration as it affects factory operations and business practices. The sections below summarize a research agenda that is discussed in detail in Chapters 3 through 6. The largest part of the research recommended in this report is aimed at developing various IT-based tools to support advanced manufacturing. Product and Process Design Product design and process design depend heavily on human judgment. Research is needed both to develop information tools that can help human designers make good decisions in their design work and to increase understanding of the design process itself. Enabling the creation of better tools and facilitating the design process could, for example, make it easier to generate a requirements specification that meets customer needs or to design a product or a process "from scratch" and/or through the reuse of existing and validated designs. Although better tools and techniques are needed in all fields, product and process design for mechanical components and assemblies is especially important. The committee believes that a research agenda for product design (especially for the design of mechanical products) should build to the extent possible on the lessons learned in the design of electronic products such as integrated circuit chips. For example, the design of electronics today is based on having, at each
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Page 43 stage in the design process, design abstractions that contain only the detail relevant to that stage. Using these abstractions, the product designer can postpone decisions about details and focus on higher-order questions about function, leaving the detail to the subsequent stages in which lower-level issues can be resolved. Designers of electronic products also have an extensive set of predefined and prevalidated "parts" that can be used as building blocks in product design; altering the parameters of these predefined parts allows some customizing of the product being designed. Such capabilities also need to be made available to designers of mechanical products. Although mechanical products differ qualitatively from electronic products (e.g., mechanical products are three-dimensional, and interactions among their components are more analytically intractable), making their mechanical design as easy as the design of electronic products today is a reasonable asymptotic goal to work toward. In addition, tools are needed that will enable the identification of trade-offs between cost and dimensions of performance such as reliability, power consumption, and speed; between cost and design choices; between alternate space allocations; or in functional decomposition, subassembly definition, three-dimensional geometric reasoning, and make-or-buy decisions. In the domain of process design, tools for describing processes are critical for the design of individual products, the design and operation of factories, and the development of modeling and simulation technology. Formal descriptions are necessary if processes are to be represented in sufficient detail and with enough specificity to be adequately complete and unambiguous; such formalisms would allow designers to describe factory processes (involving both machines and people), design activities, and decision processes, among others. Languages for describing processes must facilitate checking for correctness and completeness and must be able to express variant as well as nominal process behavior. New tools for describing and representing processes could also be used to enhance product design, so that by simulation and emulation the best process could be matched to the product design (and vice versa) for maximum economic advantage (or to satisfy whatever criteriasuch as quality or time to deliveryare important for the particular case). Used in this way, simulation and emulation could facilitate "design for manufacturability" and "design for assembly," which should also encompass design for rapid testing and diagnosis, fast maintenance and repair, quality control, and material handling, as well as design for modeling more efficient factory processes and operations. Shop Floor Control By automating processes, extending the uses of sensors, and improving scheduling, information technology can play a vital role in improving the flow of material and the routine control functions of machine tools, robots, automated guided vehicles, and many other basic machines on the factory floor.
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Page 44 Research is needed to advance the level of process automation, including greater ease of interconnection of factory equipment and more automated responses to problems. The current thrust today in systems development is toward open systems that allow equipment from different manufacturers to be "mixed and matched" as needed. Achievement of an open equipment controller architecture that would enable all factory and shop floor components to share the same programming environment, communication facilities, and other computer resources would contribute to the interconnection of factory equipment (as well as to enterprise integration). Advanced manufacturing languages that would be more flexible than existing languages for programming unit processes (such as APT and Compac for machining) would support the operation of accessory devices in conjunction with a particular process and be more closely coupled to product data generated by CAD/CAM systems (to facilitate direct transfer of products from blueprint to production). Research is needed on advanced sensor systems as well. Sensors provide real-time feedback about the operation of a process during manufacturing (e.g., unpredicted part-tool interactions). Historically, sensors have served only as production monitors. Increasingly, they are becoming active components of production systems, integral to either a process or a finished product. Standardized sensor architectures must be developed so that sensors and actuators can be plugged into a common control system with only minor, automatic reconfiguration. Sensors connected through such architectures would be linked directly into databases for dynamic updates usable by machine controllers. Standardized sensor architectures will require a uniform method of characterizing sensors and actuators suitable for automation, applicable to a wide range of devices. Data fusion techniques for correlating inputs from multiple sensors would help overcome the difficulties of sensing in a relatively "dirty" environment. Intelligent sensors would be able to process shop floor data to higher levels of abstraction to determine their significance to manufacturing decisions. Effective real-time, dynamic scheduling of factory operations on the shop floor remains a major problem but has great potential for improving factory performance. Dynamic scheduling is desirable because management priorities for production must be balanced moment to moment against circumstances prevailing in a plant and in the manufacturer's supply chain (e.g., sudden changes in conditions generated by drifts in machine capability, material shortages, unplanned equipment downtime, delays in arrival of necessary components). Dynamic scheduling would determine what should be done next by any particular piece of equipment at any particular moment based on current conditions throughout the factory. Research is needed to develop real-time scheduling tools that would provide capabilities for integrating scheduling and control reactively (e.g., tools that would make use of adaptive scheduling techniques based on the severity of the contingency at hand and the time available to adjust the schedule and/or
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Page 45 scheduling techniques that could exploit windows of opportunity occurring fortuitously). Also needed are information tools and techniques to ensure graceful degradation of plant operations in the event of local problems. Factory managers and operations teams will require effective means to support overall situation assessment, both within a factory (e.g., knowing when certain machines are inoperable, knowing the location of various parts) and outside it (e.g., knowing that a delivery will be delayed). They will also require tools that integrate multiple dimensions in which managers must make decisions, including decisions about product release, reordering, sequencing and batching, safety stock and safety lead-time, use of overtime, and order promising. Autonomous agent-based architectures are a potential alternative to top-down scheduling. Autonomous agents (implemented as software objects or collections of objects, perhaps represented by physical robotic agents) could be attractive for manufacturing applications in the areas of planning, monitoring, and control. Important research problems connected with agent-based architectures include the level of autonomy that agents in various locations should have and how collections of agents would maintain stability when given potentially contradictory goals. The deployment of agents might well be risky until these issues are addressed in detail. Modeling and Simulation To realize a virtual factory that can faithfully reflect the operation of a real one in all relevant dimensions, it will be necessary to represent real manufacturing operations at different levels of abstraction. All objects in a real factory, whether they are pieces of equipment, product lots, human resources, process descriptions, data and information packets, or facilities, must have direct counterparts in the virtual factory; indeed, the actual production facility in which raw materials are transformed into physical products is itself one level of abstraction in a comprehensive virtual factory model. The boundaries of the virtual model must be flexible, capable of incorporating activities outside the factory or focusing only on entities within the factory structure as necessary for analytical purposes. Central to simulation technology is research on modeling frameworks that can link the wide variety of models representing activities from all parts of manufacturing, from design through orders to multicountry manufacturing and distribution to customer delivery; a large number of models will be needed to simulate realistically even a modest factory. The models will be distributed in time and space; research will be required to understand how to link these essential pieces in a timely manner. Work is needed not only on general modeling techniques but also on fast methods of tailoring a specific model to local conditions. Hierarchical simulation models built from well-tested fundamental equipment
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Page 46 blocks will be critical to the success of factory modeling. Similarly, procedures are needed that allow for the parallel processing of these hierarchical models so that very rapid (faster than real-time) simulation times can be achieved. A second dimension of simulation technology is how to account for the stochastic nature of events on the factory floor. Given the multitude of unexpected events that can affect factory operations (e.g., tool breakdown, late supply shipments, personnel absences) as well as decisions influencing operations (e.g., which machine is to be changed, what personnel are to be used), no single simulation run will be definitive. Rather, tools are needed that can test a given configuration or plan in thousands of probabilistically determined runs. A complete simulation that could be used for everything from analysis to control for even a modest factory is out of reach today. However, a first step would be the comprehensive simulation of an individual production line. For such a task, appropriately detailed models of individual tools are needed that can then be combined to provide overall realism. Equipment-level simulation models have been developed and used to analyze equipment-level characteristics, but the simulation of a production line would test the ability of such models to act in concert. Validation of simulation models will be essential. Since a simulation is good only to the extent that it provides an accurate representation of reality, justified and well-grounded confidence in the model is critical for use and implementation. Simulation models can always be tweaked and otherwise forced to fit empirical data, but the purpose of simulation is to learn something reliable about a hypothetical factory operation for which no empirical data exist. Managers and decision makers will need high levels of assurance that a simulation's prediction of a new factory faithfully reflects what would actually occur, even taking into account the random events that affect today's manufacturing systems so adversely. Well-validated simulations would enable the creation of a demonstration platform that could compare results of a real factory system before the system ever operates. Tools to automate the process of sensitivity analysis for simulations would be particularly helpful in coping with the stochastic factory environment. Ultimately, the modeling and simulation capabilities resulting from the research outlined here should be able to support configuring and constructing a real factory for high-level performance (on multiple dimensions), as well as planning how best to operate it once it has been constructed. A concrete demonstration of these capabilities would be the creation of a platform capable of comparing the results of real factory operations with the results of simulated factory operations using information technology applications such as those discussed in this report. For modeling and simulation to serve manufacturing needs, two broad areas of research stand out for special attention: the development of information technology to handle simulation models in a useful and timely manner, and capture of the manufacturing knowledge that must be reflected in the models.
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Page 47 Enterprise Integration and Business Practices Research is needed to extend and enhance the information infrastructure supporting manufacturing enterprises, including both the internal infrastructure used within a factory (perhaps a dispersed one) and the external infrastructure that increasingly links an enterprise to its suppliers, partners, and customers. The use of networks by all kinds of personnel and of equipment to exchange all kinds of data (text, numeric, graphic, and video) calls for high bandwidth; greater dependability and security; greater support for real-time communication, monitoring, and control; and better interoperability (through architectures, standards, and interfaces) for component systems and networks of different types. Achieving ease of interconnection is essential; attaching equipment and subsystems to a factory information system should be as easy as plugging household appliances into outlets, at least in principle. Beyond better network-related facilities, there is a need for better technology for the exchange of information, information services to support integration of applications, and standard representations, protocols, libraries, and query languages. In addition, enterprise integration requires research and development relating to the interconnection of applications. Indeed, much of today's manufacturing information technology can be characterized as islands of automation that are unable to communicate with each other due to incompatibilities in their representation of largely similar information. Enabling intercommunication will require the development of appropriate ways of explicitly representing information related to products, fabrication processes, and business processes, as well as how each element relates to itself and to other elements. These new representation schemes will themselves demand a deep understanding of the underlying information, an understanding that is sorely lacking in many of the domains that relate to manufacturing. Research is also needed on organizing principles and architectures for connecting different network-based applications into a seamless environment. Such connection is necessary, for example, to link flexible manufacturing cells to the plant scheduling function and to link the scheduling function to the enterprise order, delivery, and financial systems. Enterprise integration also implies a need for research to enable the automatic interpretation of the type of transaction being executed, the routing of the message to the right location for processing, and the processing that must occur when the message for the transaction reaches the correct system. Integration of individual enterprises into the marketplace in the information age will require security and authentication features that guarantee the integrity of electronic transactions. Non-Technology Issues Expanding the scope of what is achievable by information technology is only one dimension of realizing a 21st-century vision of manufacturing. It is equally
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Page 48 important to understand how manufacturing enterprises can actually make use of the technology. Even today, much useful technology remains unused. Innovators in manufacturing must ensure that human, institutional, and societal factors are aligned in such a way that information technology can be deployed meaningfully. This is a difficult but essential task, since even great technology that goes unused is not particularly beneficial to anyone. Data, information, and decisions need to be communicated accurately across the breadth and depth of manufacturing organizations. Many mechanisms can contribute to enhancing communication, including sabbatical programs for industrialists and academics in each other's territory, teaching factories, and advanced technology demonstrations that illustrate how the use of information technology can benefit factory performance. Considerable research in social science will be necessary to facilitate the large-scale introduction of information technology into manufacturing. In particular, fully exploiting new technologies generally requires new social structures. Innovators will have to confront issues such as the division of labor between human and computer actors, the extent and content of communications between those actors, and how best to organize teams of human and computer resources. Matters related to education and training will be central to 21st-century manufacturing. Given an environment of increasingly rapid change, continual upgrading of skills and intellectual tools will be necessary at all levels of the corporate hierarchy. "Just-in-time learning," that is, learning things as it becomes necessary to know them, may assume added importance. Finally, although businesses depend increasingly on their intellectual and information assets, generally accepted accounting principles that businesses use to audit their finances and operations are derived from a business philosophy in which capital expenditures (i.e., expenditures that relate to the long-term value of a company) are associated with buildings and pieces of equipment. Research is needed to develop valuation schemes that appropriately account for the contribution of knowledge and core competencies to manufacturing and enterprise values.
Representative terms from entire chapter: