Toward a New Era in U.S. Manufacturing The Need for a National Vision (1986) / Chapter Skim
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Appendix A: The Technology of Future Manufacturing
Appendix A: The Technology of Future Manufacturing
Pages 75-125
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From page 75... ...
DEVELOPMENTS IN MANUFACTURING MATERIALS Materials developments have a substantial impact on manufacturing in both product design and process engineering. New products can require different materials and materials processing, and new materials themselves often spur new products and new process development.
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From page 76... ...
Developments in both conventional materials and new materials are equally significant to future manufacturing. This section will focus on materials developments that are ready for manufacturing implementation, with minimal emphasis on research systems that have had little technology transfer effort.
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From page 77... ...
In the new metals area, continued progress is expected in the development of metal matrix composites, particularly using metals such as aluminum and magnesium reinforced with silicon carbide. Three major types of reinforcement are receiving particular attention: continuous monofilament, discontinuous, and continuous multifilament yarn.
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From page 78... ...
Unfortunately, research on fracture mechanics in the area of metal matrix composites is much less developed than for polymer matrixes and has not been widely disseminated for use by designers.) Progress in reducing material defects and continued application experience will result in broader applications for metal matrix composites.
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From page 79... ...
. Beyond the relatively simple polymer applications, adhesives are increasingly required for bonding dissimilar materials, particularly when differential thermal expansion must be accommodated.
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From page 80... ...
In contrast to traditional ceramics, which are made from natural raw materials such as silica and clay, advanced ceramics are made from artificial raw materials, such as aluminum oxide, zirconia, yttria, silicon nitride, and silicon carbide, which are formed, sintered, and treated under precisely controlled conditions. The advantage of such fine ceramics is their ability to play both functional and structural roles.
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From page 81... ...
Important research also is needed to identify new, more complex ceramics. Significant advances also are being made in thermal barrier coatings and ceramic matrix composites.
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From page 82... ...
This lack is a severe handicap in manufacturing process development. Most materials handbook data have been generated for use in product design and service performance analysis rather than for process analysis.
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From page 83... ...
Despite the handicaps, significant breakthroughs can be expected so that changes in manufacturing materials will keep pace with the many other developments on the factory floor. MATERIAL HANDLING TECHNOLOGY TRENDS This section will assess the major trends in material handling technology.
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From page 84... ...
Asynchronous material handling equipment is often used to allow a worker to control the pace of the process. The trend toward asynchronous movement appears to be partially motivated by the apparent success of Japanese electronics firms in using specially designed chain conveyors that place the control of the assembly process in the hands of the assembly operators.
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From page 85... ...
A further enhancement of the carousel conveyor is automatic loading and unloading through the use of robots and special fixtures. A number of microload automated storage and retrieval systems have been introduced in recent years.
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From page 86... ...
Likewise, the expectation is that the greatest impact in the future will come from the application of artificial intelligence to transporting, storing, and controlling material. Among the alternative sensor technologies available to support automatic identification are a wide range of bar code technologies, optical character recognition, magnetic code readers, radio frequency and surface acoustical wave transponders, machine vision, fiber optics, voice recognition, tactile sensors, and chemical sensors.
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From page 87... ...
being developed by a number of firms led by General Motors (discussed in the section Factory Communications and Systems Technologies, under the subsection Networks) is expected to provide the common data transmission link by which many different types of manufacturing hardware, including material handling equipment, will communicate.
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From page 88... ...
machine tools and smart robots to computer-aided design and artificial intelligence, developments whose impetus comes from rapid advances in microelectronics and computer science. Rapid developments in very large scale integration of integrated circuits have reduced the size, cost, and support requirements of information and machine intelligence while greatly increasing its capabilities.
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From page 89... ...
Both of these new classes of machines can be equipped with automatic tool-changing devices and often have automatic work loading, sensors to check on operating conditions, measuring devices, and other features that enable them to operate for long periods on different workpieces with little or no operator attention. With such versatility, a machining center and a turning center working together can perform all of the basic cutting operations on virtually any part that falls within the operating size limits of the machines.
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From page 90... ...
Higher-power lasers are now used for welding and for sheet and plate metal cutting. Within the past two years, precision machine tools that use the laser as a cutting too]
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From page 91... ...
process specifications, and changing lot sizes will create an ever-increasing need to match specific tooling with specific production applications. To achieve the high-quality, close-tolerance production demanded in the marketplace, manufacturers will require a large inventory of tooling to ensure that the optimal tooling is available for all production requirements.
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From page 92... ...
When a variety of tasks are performed, a large number of fixtures must be developed, stored, and accessed a very expensive undertaking. The need for a large number of fixtures remains a problem even for flexible manufacturing systems (FMSs)
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From page 93... ...
. The fixtures would be mounted on standard pallets, permitting robots to load and unload parts easily and allowing easy alignment with machine tools.
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From page 94... ...
Sensors to determine what is happening and monitoring systems to evaluate the sensor information are both needed. The role of sensors in a manufacturing environment is to gather data for adaptive control systems-for example, to supply guidance information to robots or to provide measurements for quality assurance and inspection systems.
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From page 95... ...
For example, research is under way on vision systems that can inspect IC wafer reticles. Research on this vision system is focused on the mechanical accuracy of positioning devices, on the interface to the CAD data base describing the reticle, and on modeling the fabrication process to predict what the vision system will see.
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From page 96... ...
About one-third of the cost of a robot work cell is the fixturing that holds or feeds each part in precisely the same way each time. This cost can be saved by smart robots that can find the part they need even if it is askew, upside-down, or in a bin with other parts; it is easier to change a robot program than to change the fixturing.
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From page 97... ...
However, these programming languages are limited because they can neither interpret complex sensory data, as from a vision or tactile sensor, nor access CAD data bases to get the information they may need to identify the parts that they sense. Present languages are also robot dependent; that is, they do not allow the transfer of programs from one robot to another.
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From page 98... ...
Other, more significant, benefits over the long run concern the use of the data in the CAD data base. These data a computerized representation of the parts can be used by the engineering and process planning functions, saving much reentering of data, eliminating sources of human error, and opening up a great avenue for cooperative design that includes feedback from engineering and manufacturing.
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From page 99... ...
For this reason, graphic simulation will be treated here, and mathematical modeling will be covered later in the communications and systems section. Graphic robot simulation is beginning to be used to select the most appropriate robot for a particular task or work cell and to plan the cell layout.
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From page 100... ...
Artificial Intelligence Artificial intelligence is a set of advanced computer software applicable to classes of nondeterministic problems such as natural language understanding, image understanding, expert systems, knowledge acquisition and representation, heuristic search, deductive reasoning, and planning. ~ ~ Artificial intelligence (AI)
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From page 101... ...
The Al software will determine what he means, even if the request has been phrased conversationally or colloquially, and provide interactive assistance for decision making. By the year 2000, managers will probably be communicating with their work stations by voice, another application of Al techniques.
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From page 102... ...
As an information communication method, it virtually guarantees delay, inaccuracy, and expense. The advent of computer technology and network communications is changing the face of the factory floor, much as office automation has changed the front office.
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From page 104... ...
Systems of manufacturing are integrated through the application of several technologies: communication networks, interface development, data integration, hierarchical and adaptive closedloop control, group technology and structured analysis and design systems, factory management and control systems, modeling and optimization techniques, and flexible manufacturing systems. Artificial intelligence techniques will be embedded in, and inseparable from, most of these technologies.
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From page 105... ...
Networks The manufacturing network will be the backbone of factory communications and, therefore, of factory automation. Communications between tightly coupled components, such as robots and sensors, and between elements of an FMS require that data be exchanged in real time.
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From page 106... ...
Interface Standards The network is expected to provide the physical and log~cal path for data communication in a factory system, but much more is required for effective communication. Networks provide the physical language and format, but do not address the semantics or effective use of the information communicated.
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From page 107... ...
This would facilitate compatibility of the equipment of multiple vendors in the heterogeneous systems expected in the factory of the future. Interface standards of this type are the basis of research at the Automated Manufacturing Research Facility at NBS.
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From page 108... ...
. Currently under research, task programming systems will reduce programming requirements to the steps on a common process planning sheet so that programmable manufacturing systems of the future will be controlled by statements similar to those one would give to a person doing the same task.
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From page 109... ...
The most serious immediate barrier to the integration of manufacturing data is the incompatibility of CAD data with information needed by computer-aided engineering (CAE) and process planning.
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From page 110... ...
The CAD data base currently cannot capture the relationship of the parts to the whole, but both CAE and process planning require detailed attention to the joining of separate parts, their mating surfaces and tolerances, and their overall dimensions ad ter assembly. The CAD data base does not include knowledge or specification of materials, but CAE needs material data for its engineering analyses, process planning needs it in the creation of NC programs, and material handling needs it to select material from inventory.
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From page 111... ...
Future data bases will have more flexible schemes so that, for example, materials information can be added to the CAD data base by an engineer at a CAE station or by an expert system that contains knowledge of materials and applications. Beyond the compatibility problem are other technical challenges to the implementation of manufacturing data base systems.
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From page 112... ...
Although it is relatively simple to define GT, it is difficult to create and install a GT system because of the difficulty in defining clearly how similar one part is to another. For example, parts can be categorized in terms of shape or manufacturing process requirements.
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From page 113... ...
The software necessary to implement design retrieval is the simplest of all GT software; it involves a simple query to a GT data base for specific feasible ranges of variables. Flexible manufacturing systems exemplify a more sophisticated and more profitable GT implementation.
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From page 114... ...
This adaptive closed-Ioop control will be used at all levels of manufacturing systems from sensor-based feedback to robots or NC tools, to inspection station-based feedback to a cell controller, to a factory floor data collection system that feeds back to process planning and scheduling systems. This property
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From page 115... ...
Factory Management and Control The factory of the future will be managed and controlled through automated process planning, scheduling, modeling, and optimization systems. The successful implementation of largescale factory-level systems depends upon structured analysis and design systems that depend heavily on GT.
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From page 116... ...
Through the use of terminals on the factory floor and throughout the decision-making structure, the system can respond instantaneously to human command. At first, most of the decision making will rest in the hands of humans.
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From page 117... ...
With such optimization capability, managers will be able to sit at their work stations and, in real time, analyze the various possibilities to determine optimal solutions and mixes. The availability of accurate information on cost, time, and quality will eliminate much of the guesswork in manufacturing decision making.
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From page 118... ...
Comparisons by MBB of the performance of this FMS versus the projected performance of stand-alone NC machine tools doing the same work clearly show the advantages of the FMS approach: number of machine tools decreased 52.6 percent; workforce reduced 52.6 percent; · tooling costs reduced 30 percent; · throughput increased 25 percent; · capital investment 10 percent less than for stand-alone equipment; and · annual costs decreased 24 percent.~4 U.S. statistics for FMS installations are no less startling.
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From page 119... ...
These benefits are illustrated by the following data from five companies that have implemented advanced manufacturing technologies over the past 1~20 years:~5 Reduction in engineering design cost Reduction in overall lead-time Increase in product quality Increase in capability of engineers Increase in productivity of production operations Increase in productivity of capital equipment Reduction in work-in-process Reduction in personnel costs 15-30 percent 30-60 percent 2-5 times 3-35 times 40-70 percent 2-3 times 30-60 percent 5-20 percent The cumulative gains of total system integration can be expected to build on these results exponentially. The long-range goal of CIM is the complete integration of all the elements of the manufacturing subsystems, starting with the conception and modeling of products and ending with shipment and servicing.
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From page 120... ...
Such islands of automation are found in design, where CAD work stations from different vendors share their data through a common data base and data conversion interfaces; in planning, with manufacturing resource planning (MRP) systems; and in production, where a work cell composed of a robot, machine tool, and inspection station may be coordinated by a cell controller.
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From page 121... ...
On the factory floor, several work cells may be integrated with a material handling system to create an FMS. In the factory of the future, these continents of automation will be integrated into worlds of automation that wfl]
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From page 122... ...
Manufacturing subsystems on the factory floor will integrate traditional manufacturing processes by coupling and controlling previously separated processes and by carrying out computergenerated process plans. At the lowest level, this will involve data communication from sensors to a computer-controlled machine or robot.
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From page 123... ...
Resource aBocation subsystems span a broad scope from small-scale material handling systems serving individual work cells to broadly implemented systems that monitor and control inventory, schedule work, and allocate materials to the factory floor on tight schedules. Automated material handling systems can be integrated into work cells and families of work cells to produce a powerful FMS.
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From page 124... ...
However, consistent with the European dominance in material handling equipment technology that has existed for many years, the Barrett Corporation was acquired by a European firm, the Mannesmann Demag Corporation. This section is based on Thompson, Brian, 1985, Fixturing: The Next Frontier in the Evolution of Flexible Manufacturing Cells, CIM (March/April)
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From page 125... ...
Dearborn, Mich.: Society of Manufacturing Engineers. iiCommittee on Army Robotics and Artificial Intelligence.
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