Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 75
APPENDIX A
The Technology of
Future Manufacturing
Although ah the interrelationships and long-term implica-
tions of advanced manufacturing technologies are not yet wed un-
derstood, the direction of future developments is relatively clear.
This appendix describes the technologies that are likely to have
a major impact on manufacturing competitiveness, indicates the
ways in which those technologies interact, identifies additional re-
search needs, and discusses some of the issues that are likely to
be encountered in implementation. The technologies have been
divided into materials, material handling, material transforma-
tion, and data communication and systems integration. These
categories are highly interdependent, and divisions are not always
distinct, but this categorization provides an effective structure for
a broad overview of the major technologies.
DEVELOPMENTS IN MANUFACTURING MATERIALS
Materials developments have a substantial impact on manu-
facturing in both product design and process engineering. New
products can require different materials and materials process-
ing, and new materials themselves often spur new products and
new process development. Many of the materials developments in
manufacturing do not involve new materials, but rather substitu-
tions, upgradings, and new concepts for conventional materials.
Pressure to lower costs and raise product quality has led to some
75
OCR for page 76
76
major shifts in materials selection. The consideration of doubly
precoated steel for corrosion resistance in automobiles is an ex-
ample. 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.
Developments in metals, polymers, ceramics, and glasses will be
considered, followed by a brief discussion of some emerging issues
that should be brought to the attention of policymakers.
Metals and Metal-Based Composites
Major developments will continue in the processing of con-
ventional metallurgical systems. For example, large tonnages of
carbon and stainless steed sheet and strip will be continuously
cast. Similar developments are certain in nonferrous alloy areas
as well. While the continuously cast products will have some mi-
nor metallurgical variations to be considered, the major impact
will be economic, allowing the basic metals industry to remain
competitive in many sheet and strip applications.
Increased use of warm- and cold-formed steel parts can be ex-
pected, with emphasis on near-net-shape processes to save metal
and avoid intermediate processing steps. Similar forces will con-
tinue to drive powder metallurgical processing, although it must
be emphasized that advances in precision forming and powder
metallurgy have been slow over many years rather than a sudden
breakthrough. Powder processing will be facilitated as cleaner
powders reach the market. Powder metallurgy produced too!
steels continue to offer advantages over conventional tooling stock.
Superplastic forming will continue to increase in aerospace
manufacturing; some initial applications have occurred in the B-1
bomber program. Increased market penetration will entail ma-
jor changes in tooling and manufacturing technology. Thermo-
mechanically processed 7000 series aluminum alloys are available
for such forming, as are aluminum-lithium alloys. However, little
of these alloys are available from domestic sources; most of this
material is being obtained from the United Kingdom.
OCR for page 77
77
Many metal-processing alternatives will be examined to facil-
itate in-line processing systems. Improvements can be expected
in the control of metal structure, with increasing awareness of the
importance of grain orientation (texture), residual stress, and sur-
face quality. In steed surface treatment, increased use of induction
or laser hardening can be expected as lower cost alternatives to
carburizing. I.aser welding is seen as growing in the auto industry,
perhaps at the expense of electron beam techniques. Power sys-
tems manufacturing may turn to welded rotor fabrication to allow
increased use of attractive alloy combinations while sidestepping
large forging development problems.
Many cases of metals substitution can be expected. The
upgrading of alloys in small parts should increase product qual-
ity, reliability, and processing response without grossly increasing
overall metal procurement cost. Aluminum can be expected to
continue to replace copper in many heat exchange applications.
Silicon-based switches are expected to replace iron-based mag-
netic devices. Also in the electronics industry, changes in plat-
ing metals are expected, with gold giving way to palIadium-nicke!
and iron. Some observers see increased use of molybdenum-based
alloys, particularly as new developments solve some of the tradi-
tional corrosion problems. Production of these alloys is energy
intensive, however, and the domestic supply is limited.
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 at-
tention: continuous monofilament, discontinuous, and continuous
multifilament yarn. Each reinforcement requires a specific fab-
rication process, including diffusion bonding, hot molding, power
blending, forging, casting, pultrusion, extrusion, and rolling, often
in combination. Many of the material defects and anomalies that
have plagued metal matrix development are attributable to the
manufacturing process. As experience in these processes builds
and the manufacturing technology evolves, application problems
caused by material defects should decrease. In aerospace struc-
tures, for example, the application of specific metal matrix materi-
als varies according to expected environment, design Toads, stress,
OCR for page 78
78
and temperature variations. Designers of flaw-critical parts select
materials for their strength and ductility as well as their resistance
to crack growth. 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 applica-
tion experience will result in broader applications for metal ma-
trix composites. For example, automobile manufacturers are gain-
ing experience with aluminum-silicon carbide in piston ring and
crankshaft applications. Power systems applications are seen for
nickel superalloy and stainless steel matrix composites strength-
ened with silicon carbide. Such systems allow increases in elastic
modulus and desirable decreases in the coefficient of thermal ex
panslon.
Much research has focused on rapidly solidified metals and
amorphous metals. Introduction of such materials into the manu-
facturing sector is expected to be slow, with the major exception
of the iron-boron-silicon-carbon system being broadly used for dis-
tribution transformers. Slow emergence is also predicted for nickel
and titanium aluminides despite extensive research. Recent alu-
minide development has greatly increased its durability, and some
jet engine applications can be expected.
Polymers and Polymer-Based Composites
Polymers and polymer-based composites will probably con-
tinue to displace carbon steel and aluminum in a significant seg-
ment of structural and paneling applications. This trend may be
most prominent in the automobile industry, but it is also likely
in electronic hardware, appliance chassis applications, and home
building components. Current automobiles contain about 157
pounds of plastics and polymer-based composites. By 1995, this
should grow to 213 pounds as polymer materials are used increas-
ingly in body panels. The increased use of plastic is expected to
save motorists about $200 per year through fuel economy, corro-
sion resistance, cheaper repairs, and lower insurance rates.2
OCR for page 79
79
The applications seen in models such as the Pontiac Fiero will
spread for reasons of economy and safety. In the Fiero, the hori-
zontal body panels are made of flexible glass fiber-fi~led polyester
(a sheet molding compound) and the vertical panels are made of
relatively stiffer glass-reinforced polyurethane (a reaction injec-
tion molded product). Beyond the body pane} substitutions, fur-
ther use of polymers can be expected in the automobile structure.
For example, polymeric leaf springs have been used in some auto-
mobiles since 1981. While glass-polyester and glass-polyurethane
materials will see major tonnage applications, future use of poly-
mers in automobiles con be expected to rely on reaction injection
molded thermoplastics as well. Beyond these applications, the ex-
panded use of coatings (including paint) on steel can be regarded
as an area where polymers will intrude further into the sheet metal
markets.
The growth of polymer panels and structural shapes has ne-
cessitated the development of adhesives as a joining medium. In
addition to the increased use of conventional adhesive materi-
als, advanced work is under way on adhesive systems for higher-
temperature applications (epoxies, polyimides), adhesives with
greater strength and elastic range than epoxies, primerIess adhe-
sives (silicones perhaps), and faster-curing adhesives (cyanoacry-
lates, urethanes, etch. In some instances, adhesive development
overlaps sealant systems (silicones). Beyond the relatively sim-
ple polymer applications, adhesives are increasingly required for
bonding dissimilar materials, particularly when differential ther-
mal expansion must be accommodated. For example, rivets can-
not be used to join plastic liners to metal trailer bodies because
of differential thermal expansion. In some metal joining develop-
ments, adhesives are being used in conjunction with spot welding
to replace riveting. However, it must be emphasized that the use
of adhesives for nonpolymeric joining has been slowed consider-
ably by concerns about reliability, contamination, degradation,
and consumer acceptance.
Another major shift in polymer materials use can be fore-
seen where flame retardation is a dominant consideration. Under-
writers Laboratory interpretations of smoke, flame, and toxicity
OCR for page 80
80
requirements are leading to shifts away from polyvinyl chioride-
based systems to fluorocarbons.
High-Technology Ceramics
Advanced high-technology ceramics3 are nonmetallic materi-
als having combinations of fine-scale microstructures, purity, com-
plex crystal structures, and precisely controlled additives. In con-
trast 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. Functional uses include optical devices, motors,
transducers, sensors, and semiconductors; structural uses include
those that require high specific strength, high wear resistance, and
high corrosion resistance. Both roles will be increasingly impor-
tant in manufacturing applications.
Currently, high-technology ceramics are used most often in
electronics, including optical fibers, multilayer ceram~c-to-metal
interconnecting and mounting packages for integrated circuits, ce-
ramic multilayer chip capacitors, piezoelectric ceramic transduc-
ers, and chemical, mechanical, and thermal sensors. Processing for
these applications is generally an extension of standard ceramic
technology, in which powders are pressed or formed with binders
and sintered to density the ceramics. Incremental progress has im-
proved results, but major improvements cannot be expected until
semiconductor processing techniques are applied to ceramic com-
ponents. Techniques such as selective-area ion implantation and
laser-induced recrystallization will greatly improve many of the
properties of electronics ceramics.
High-technology structural ceramics are used as coatings and
for monolithic and composite components. Major applications in-
clude tooling for metal working, wear components in a variety
of abrasive environments, bioceram~cs for bone replacement, and
military ceramics for radomes and armor. Major efforts are un-
der way in both the United States and Japan to use structural
OCR for page 81
81
ceramics in a variety of automotive applications, including engine
wear components, turbochargers, bearings, and a variety of diesel
engine components.
Significant strides have been made in the mechanical prop-
erties and reliability of monolithic structural ceramics. Under-
standing of strength-limiting flaws and temperature-brittle frac-
ture behavior has improved greatly, but further work is needed to
improve reliability. Improvements are needed in powder synthe-
sis, powder properties, near-net-shape fabrication methods, mi-
crostructure control, mechanical properties, and nondestructive
testing methods. 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. Ceramic matrices com-
bined with particulates, whiskers, or fibers of a different ceramic
compound or metal have yielded composites with five times the
resistance to fracture of the monolithic ceramics. Recent success
has been reported in the use of metal ion implantation to reduce
the relative friction resistance of ceramic diesel engine parts.4 New
research is needed to quantify the improved mechanical properties
of composites, particularly fracture resistance.
In addition to the research required on the composition and
properties of ceramic materials, much work is needed on the pro-
cessing and product design requirements of ceramics. Promising
directions in ceramic processing include the use of ultrafine pow-
ders and the use of chemical routes to supplement or bypass some
of the powder-processing stages. Other requirements include the
processing of fine-scale layered structures, processing of ceramic
composites, joining of ceramic parts, and near-net-shape process-
ing of complex parts to minimize machining requirements.
The rate of technical progress in ceramic materials and pro-
cessing will determine the pace of commercial application. Major
market penetration for structural ceramics depends largely on the
progress made in automobile applications. Several Japanese firms
have already introduced ceramic turbocharger rotors, piston rings,
swirl chambers, and camshafts.5 An almost totally ceramic engine
is a major research objective of virtually every automobile manu-
facturer and should be extant by the early 1990s. As these auto
OCR for page 82
82
motive applications increase and the price falls, high-technology
ceramics can be expected to see rapid growth in product and pro-
cess (cutting tools) applications.6
General Issues Related to Materials
It is important to recognize the critical lack of data on and
basic understanding of the physical properties of many materials.
This lack is a severe handicap in manufacturing process develop-
ment. Most materials handbook data have been generated for use
in product design and service performance analysis rather than
for process analysis. The lack of knowledge has become acute
as software systems have emerged with powerful process control
and process design capabilities. The requisite data inputs often
involve combinations of stress, strain, strain rate, temperature,
heat transfer, friction, and so on, which have not been studied
even for classic engineering materials.
This lack of data on manufacturing materials grossly compro-
mises the effectiveness of computer-based process models, and it
tends to foster undue reliance on the few materials for which an
adequate data base seems to exist. Power systems in particular
are plagued by a lack of materials innovation due to the awesome
data base requirements for service performance analysis, manu-
facturing modeling, and code adherence. With the current low
return on investment in much of the primary materials industry,
little supplier information is being generated. While some man-
ufacturers develop their own data bases, others find that largely
empirical trials are the least expensive approach (from a local
point of view).
The scientific community has been reluctant to get involved
in data-generating efforts that involve "no new science." Federal
funding agencies, reinforced by peer review systems, also have
shunned this area. Progress in generating this data could have a
significant impact on a variety of industries and process applica-
tions.
Another recurring concern is the frequent lack of domestic
suppliers for new materials, such as some ceramics. Manufacturers
are reluctant to begin using new materials systems when only one
OCR for page 83
83
or perhaps no domestic supplier exists. Many new materials are
initially imported in quantity from Japan or Europe.
A related problem is the growing tendency for manufacturers
and wholesalers to limit inventory. Indeed, limiting inventories has
emerged as a smart manufacturing practice, especially with high
interest rates. However, this practice grossly limits the availability
of new and many old materials for manufacturing trials. In fact,
most of the materials in reference handbooks are not available in
tryout quantities.
Lastly, there is an important interaction between the use of
new materials and recycling and scrap practices. This is particu-
larly the case in the automobile industry, in which a by-product
of primarily steel construction has been the relative purity of car
bodies as a source of steed scrap. The ease of recycling car bodies
is being compromised by the materials substitutions now occur-
ring, which could significantly increase material costs in a number
of industries.
Although these problems slow progress, none is sufficient to
prevent increased use of new materials in manufacturing if those
materials are cost effective in production, performance, and main-
tenance. Limited availability is probably the greatest handicap,
because the machining, tooling, and processing required for many
new materials can be vastly different from those for traditional
metal cutting; significant research in a production environment
is a prerequisite for increased use. Fortunately, enough produc-
tion experience is being accumulated with many new materials,
particularly polymers, to demonstrate their advantages and to
encourage efforts in other areas of materials research. 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. Material handling systems are used to enhance hu-
man capabilities in terms of speed of movement, weight lifted,
reach distance, speed of though", sensory abilities of touch, sight,
OCR for page 84
84
smell, and hearing, and the ability to deal with harsh environ-
ments. In this area, it is important to distinguish between equip-
ment technology and design technology. Equipment technology is
categorized by its primary functions: transporting, storing, and
controlling materials.
Transporting
The material handling function of transporting material has
been affected significantly by two trends toward smaller loads
and toward asynchronous movement. The former is the result
of the drive to lower inventory levels through just-in-time pro-
duction. It has been manifested in the development of numerous
equipment alternatives that have been downsized for transporting
tote boxes and individual items rather than the traditional pallet
Toads. The inverted power-and-free conveyor, powered by linear
induction motors for precise positioning and automatic loading
and unloading, is one example of the trend to develop transport
equipment for small loads. Automatic guided vehicles (AGVs)
for transporting individual tote boxes are also being developed,
as are specially designed conveyors and monorails for tote box
movement.
The use of asynchronous movement in support of assembly
has existed for many years. For example, asynchronous material
handling systems were prevalent in automotive assembly before
the paced assembly line was adopted at Ford in the early l900s,
and the concept has been applied recently in some European au-
tomotive assembly operations. In the early 1970s, Volvo began
using AGVs to achieve asynchronous handling in support of job
enlargement. 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 par-
tially 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 op-
erators. A workpiece is mounted on a platform or small pallet
which is powered by two constantly moving chains. The platform
is freed from the power chain when it reaches an operator's station.
OCR for page 85
85
After work is completed on the workpiece, the operator connects
the pallet to the chain, and it moves to the next station; if the
next station has not completed its work on the previous piece, the
pallets accumulate on the chain.
Asynchronous alternatives include using AGVs as assembly
platforms and for general transport functions; "smart" monorails
for transporting parts between work stations; transporter con-
veyors to control and dispatch work to individual work stations;
robots to perform machine loading, case packing, palletizing, as-
sembly, and other material handling tasks; microload automated
storage and retrieval machines for material transport, storage, and
control functions; cart-on-track equipment to transport material
between work stations; and manual carts for low-volume material
handling activities.
Storing
The major trends in material storage technology are strongly
influenced by the reduction in the amount of material to be stored
and the use of distributed storage. Rather than installing eight to
ten aisles of automated storage and retrieval equipment, firms are
now considering one- and two-aisTe systems. Rather than being
designed to store pallet loads of material, systems are designed
to store tote boxes and individual parts. Also, rather than a
centralized storage system, a decentralized approach is used to
store materials at the point of use.
Among the storage technology alternatives that have emerged
are storage carouse! conveyors; both horizontal and vertical rota-
tion designs are available. Furthermore, one particular carouse!
allows each individual storage level to rotate independently, clock-
wise or counterclockwise. 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 sys-
tems have been introduced in recent years. The equipment is
used to store, move, and control individual tote boxes of material.
Rather than performing pick-up and deposit operations at the end
of the aisle, the microload machine typically performs such oper
OCR for page 115
115
of adaptive feedback is the key to improving product quality, with
zero defects a realistic goal (see Figure A-1.
Adaptive feedback is also one key to better management,
since only in this way can a manager know exactly the state of
production, including exact costs. Systems of manufacturing have
a feedforward property that will allow management to control the
factory floor with an effectiveness and immediacy never before pos-
sible. (A more global discussion of hierarchical control is found in
the subsection Computer-Integrated Manufacturing Systems.)
Feedback and feedforward properties can also provide ma-
chines and systems with sel£diagnosis features. Thus, a manu-
facturing system can tell if something is wrong with it and what
is wrong and can suggest the remedy to a higher entity. For ex-
ample, researchers at the AMRF have already demonstrated the
ability to sense when a too] is about to break so that automated
equipment can change the too! without the disruption caused by
untimely failure. Next will be limited self-maintenance and repair
capabilities. When a data-intensive system breaks down, the in-
tegrity of that data is threatened. Self-diagnosis will inform the
data base system of the integrity of the data and, if it is threat-
ened, the system will take either conservative or remedial action.
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 large-
scale factory-level systems depends upon structured analysis and
design systems that depend heavily on GT. Limited structured
analysis systems, such as the Air Force-sponsored Integrated Com-
puter-Aided Manufacturing Definition, have been in use for years
in the analysis and design of large projects. Only through such sys-
tems can a manager know the exact state of his factory, and only
through such exact knowledge of the present can a manager intel-
ligently implement systems of manufacturing for the future. New
systems development methodology packages, such as STRADIS,
promise help in this area, but much work remains to be done be-
fore such systems are easily used by the actual decision makers.
OCR for page 116
116
Similar work must be done on process planning and scheduling
systems before they can use the feedback and feedforward prop-
erties of the hierarchical and adaptive closed-Ioop control systems
to be found in future manufacturing systems.
Management functions will be hierarchically distributed so
that "go" an;d "halt" decisions may be made effectively from many
levels and by human or machine. 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.
Low-leve} manufacturing systems now work in this way. As the
systems become integrated at higher and higher levels, decision
rules and methods will be built into them; systems wiD develop
plans to carry out human-specified activities. On the authorized
human's approval, the system will carry out the task, making low-
leve] decisions on its own. If a low-level decision-making entity
does not have a certain level of confidence in its decision, it may
pass the decision up to the next-higher entity, be it human or
computer. This new kind of man-machine interaction will allow
humans to do what they do best: create, define, and communicate.
The machine will do what it does best: work hard, steadily, and
accurately.
Modeling and Optimization Systems
One tried and true method of representing an activity to a
computer is through mathematical modeling. Computerized mod-
eling tools, such as SLAM, have been used by simulation experts
for years, but simulation is still more an art than a science. With
experience and feedback, our ability to represent complex activ-
ities mathematically will be refined. A modeling and simulation
package will be a necessary part of an intelligent structured anal-
ysis and design system. It is hard to overstate the importance of
structured analysis and design systems; they will operate at high
levels, with much built-in decision making.
System modeling will become a commonplace and necessary
prerequisite to the successful design and implementation of large-
scale manufacturing systems. This is because large projects con
OCR for page 117
117
tain too many facets to be managed effectively with only hu-
man memory and computation capability. Artificial intelligence
techniques will be needed to reduce the tremendous amounts of
data generated by such systems to humanly understandable terms.
This intelligence must be of a higher order than the Al expert sys-
tems in existence today.
With the addition of Al, a modeling system can become an
optimization system, guiding its human managers to the most
productive, most cost-effective, or highest-quality utilization of re-
sources. With such optimization capability, managers will be able
to sit at their work stations and, in real time, analyze the vari-
ous 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 mak-
ing.
Flexible Manufacturing Systems
Flexible manufacturing systems are expected to dominate the
factory automation movement within 10 years. These FMSs will
be tied into larger-scale manufacturing systems, but it is valuable
to consider the FMS as a critical unit or building block in total
factory integration. An FMS may be described as an integrated
system of machines, equipment, and work and too} transport ap-
paratus, using adaptive closed-Ioop control and a common com-
puter architecture to manufacture parts randomly from a select
family. The hardware components of an FMS may include an NC
tool, a robot, or an inspection station. The part family processed
by the FMS is defined by GT classification. For greatest produc-
tivity, the FMS is optimized to produce only one family of parts,
and conversely, the parts produced by the FMS are designed to
facilitate processing by the FMS.
The concept of flexibility as used in an FMS includes
parts;
· use of GT to achieve a part mix of related but different
batching, adding, and deleting of parts during operation;
dynamic routing of parts to machines;
OCR for page 118
118
and
rapid response to design changes;
making production volume sensitive to immediate demand;
dynamic reallocation of production resources In case of
breakdown or bottleneck.
Flexible manufacturing has been a reality in U.S. industry
since its introduction in 1972, and the number of new FMS instal-
lations is doubling every two years. The number and flexibility of
FMSs is expected to increase, and the cost of FMS installations
is expected to drop. Although the United States was largely re-
sponsible for the technological development of the FMS, Western
Europe and Japan both have more FMS installations than this
country. In fact, one of the most frequently cited FMS instal-
lations is located in the Messerschmidt-Boelkow-Blohm (MBB)
plant in Augsburg, West Germany. The basic elements of this
FMS are 25 NC machining centers and multispindIe gantry and
traveling-column machines; automated too! transport and tool-
changing systems; an AGV workplace transfer system; and hier-
archical computer control of all these elements. The FMS is used
to build wing-carrythrough boxes for Tornado fighter-bombers.
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. An
FMS at General Electric (GE) improves motor frame productivity
240 percent; an AVCO FMS enables 15 machines to do the work
of 65; and at Mack Trucks, an FMS parrots 5 people to do what
20 did before. In addition to productivity enhancements, the FMS
offers increased floor space capacity. GE, for example, reported
OCR for page 119
119
that floor space capacity was increased 50 percent, with a net
floor space reduction of 30 percent. An FMS can make a factory
more responsive to its market GE reported a shortening of its
manufacturing cycle from 16 days to 16 hours.
Computer-Integrated Manufacturing Systems
The technologies discussed above will be integrated to create
CIM systems whose synergy will make the whole greater than the
sum of its separate technologies. CIM systems promise dramatic
improvements in productivity, cost, quality, and cycle time. How-
ever, since full CIM has not yet been accomplished and depends
on continued technological progress, the benefits are difficult to
quantify accurately. Incremental gains from the implementation of
individual technologies and subsystems will be substantial. 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 ship-
ment and servicing. It includes the tie-in with activities such as
optimization, mathematical modeling, and scheduling.
A CIM system is created by the interconnection or integra-
tion of the processes of manufacturing with other processes or
OCR for page 120
120
systems. The resultant aggregate system provides one or more of
the following functions or characteristics:
· An information communication utility that accesses data
from the constituent parts of the system and serves as an infor-
mation communication and retrieval system.
· An information-sharing utility that integrates data across
system elements into a unified data base.
· An analysis utility that provides a mathematical mode!
of a real or hypothetical manufacturing system. Employing sim-
ulation and, when possible, optimization, this utility is used to
characterize the behavior of the modeled system in various con-
figurations.
A resource-sharing utility that employs mathematical or
heuristic algorithms to plan and control the allocation of a set of
resources to meet a demand profile.
A higher-order entity that integrates information and pro-
cessing functions into a more capable, effective processing system.
These functions and characteristics are not mutually exclusive
in actual manufacturing systems; rather, they overlap significantly
with all of the elements interconnected and integrated continually
to form a single aggregated CIM. Perhaps the most important
and least understood step in this process is the creation of an
integrated system that is a higher-order entity; this is the true
system-building goal.
Both horizontal and vertical growth of CIM systems can be
expected as the year 2000 approaches. State-of-the art technol-
ogy now includes small aggregates of computer-integrated tasks,
often called islands of automation. 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 conver-
sion 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.
In leading-edge plants, several of these islands of automa-
tion have been aggregated into larger manufacturing subsystems,
termed continents of automation. At this level of integration, links
OCR for page 121
121
exist between the design and engineering departments, with CAD
terminals and data bases sharing data with CAE work stations
and data bases. In planning, MRP can be linked to traditional
data bases containing ordering and shipping information. 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] eventually
encompass not only entire factories, but also entire corporations.
Because of the volume of data and complexity of decisions needed
for full integration, a hierarchical structure is the only feasible way
to achieve it.
A hierarchical structure has certain implications for the ar-
chitecture of CIM systems. Data use and decision making must
occur at the lowest levels possible. Only certain summary data
will be passed upward in the hierarchy to be used in reporting
the factory's state and in statistical trend analysis. Thus, an in-
formation and decision hierarchy is needed that practices man-
agement by exception. If additional information is required at
upper levels, it will be requested. If local decision making can-
not resolve a conflict, a decision wiB be requested from above.
Conversely, management decisions may be communicated almost
instantly throughout the system for rapid compliance.
The hierarchical structure further implies the use of district
uted data bases and distributed processing. A mainframe com-
puter may be the host computer to the factory of the future.
Connected to it will be an array of minicomputers, one level down
in the hierarchy, each acting as host controller to an intermediate-
level manufacturing system. A mix of local and centralized data
storage will be appropriate for each computer. Below the m~ni-
computers will be microcomputers acting as cell controllers, graph-
ics work stations, or executive work stations.
The elements of this hierarchical structure can be thought
of as subsystems, categorized by the role they play, although it
must be remembered that categories may overlap considerably.
Most subsystems of manufacturing fall into one of the following
broad categories: (1) information and communication, (2) inte-
gration of processes, or (3) resource allocation. Note that each
OCR for page 122
122
category cuts across traditional manufacturing boundaries. An
information-communication subsystem, for example, could include
a network that permits the geometric part data stored in the CAD
data base to be transformed through GT techniques into an actual
process plan and then into robot and NC programs communicated
to the factory floor. The data would then be transformed and com-
municated for process scheduling and material handling, right up
to the delivery of the finished product.
Information-oriented subsystems include traditional manage-
ment information system and data processing roles. These sub-
systems will be able to expand to include geometrical data from
CAD systems, material and process data from GT coding, parts-
in-process data, and order and inventory data. Information sum
systems will have analytic capabilities by which the data can be
massaged for quality control and trend analysis. Data retrieval
will be easier for operators and decision makers through the use
of new query languages or programs that wiD allow nonexperts
access to complex data. Most, if not all, manufacturing subsys-
tems have strong information and communication functions, even
if they are primarily process or resource oriented.
Manufacturing subsystems on the factory floor will integrate
traditional manufacturing processes by coupling and controlling
previously separated processes and by carrying out computer-
generated process plans. At the lowest level, this will involve data
communication from sensors to a computer-controlled machine or
robot. This provides the real-time adaptive control necessary to
improve the work quality and throughput of individual stations.
At the next level, factory floor manufacturing subsystems can in-
tegrate several processes, such as an NC machining station, an
automated inspection station, and the robot which services them.
In this example, the coordination is supplied by a computer which
controls the work cell. The process plan is downloaded from a
computer, which may be in the CAE area, to the work cell con-
troller, which coordinates the processing by the machines in its
cell. With automated inspection and data collection, the process
plan may be modified to eliminate defects by responding in real
time to tolerance changes. At yet a higher level, work cells are
integrated into an EMS so that an automated scheduling system
OCR for page 123
123
can assign a part in process to the next available work cell that
can perform the necessary operation. This allows a system with
fewer parts in process, shorter queues, fewer holding areas, and
much more efficient use of floor space.
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 inven-
tory, 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. In turn, the FMS can be linked to production plan-
ning and capacity planning systems to form the fully computer-
integrated manufacturing systems illustrated in Figure A-1.
One of the most important reasons for implementing smaB-
scale subsystems of manufacturing now is that they can be suc-
cessively integrated into these higher order entities, CIM sys-
tems, that benefit from the synergy between operational pro-
grams, product data, and process data.
CONCLUSION
All of these advanced manufacturing technologies, from ma-
terials and machine tools to the subsystems and CIM systems,
provide the ability to perform traditional manufacturing tasks in
a highly advantageous but nontraditional manner. Many of the
individual technologies and subsystems of manufacturing can be
implemented today and, in fact, must be implemented soon for
a manufacturer to remain competitive. Real progress toward the
factory of the future will take place through the higher-level in-
tegration of these technologies. Although a handful of domestic
manufacturers continue to make progress in implementing and in-
tegrating many of the technologies described in this appendix, real
barriers to full integration remain.
Specifically, standards are critically needed for the definition
and communication of part data. At higher levels, the need is for
proven systems of hierarchical control and feedback and usable
methods of automated classification of parts and processes (GT).
Required at the highest level are the evolution of structured anal
OCR for page 124
124
ysis and design systems that include modeling and optimization
packages, as well as intelligent user interfaces that can be used
interactively by managers in read time. The technology Is here
now or just around the corner. U.S. manufacturing needs far-
sighted management and trained manufacturing engineers to put
the pieces together.
NOTES
iMore detailed and comprehensive information on current de-
velopments in metal matrix composites can be obtained from the
National Research Council's National Materials Advisory Board.
2 The New York Times. November 17, 1985. Goodbye to Heavy
Metal, p. F-1.
3 this section is based on Research Briefing Pane! on Ceramics
and Ceramic Composites. 1985. Research Briefings 1985, pp. 60
71. Washington, D.C.: National Academy Press.
4Advanced Ceramics Technology. Pp. 23-24 in Technology
Today, March 1986.
Committee on the Status of High-Technology Ceramics in
Japan. 1984. High-Technology Ceramics in Japan, p. 30. Wash-
ington, D.C.: National Academy Press.
6 Ibid, pp. 24-25 and 33-34. Gives market growth projections
in Japan, as well as different applications given several price sce-
nar~os.
7Interestingly, the initial patents for AGVs were held by a
U.S. firm, the Barrett Corporation. However, consistent with the
European dominance in material handling equipment technology
that has existed for many years, the Barrett Corporation was ac-
quired by a European firm, the Mannesmann Demag Corporation.
This section is based on Thompson, Brian, 1985, Fixtur-
ing: The Next Frontier in the Evolution of Flexible Manufacturing
Cells, CIM (March/April):1~13.
9A good description of current developments in micromechan-
ics can be found in Brandt, Richard, 1986, Micromechanics: The
Eyes and Ears of Tomorrow's Computers, Business Week (March
17):88-89.
OCR for page 125
125
'°Smith, Donald N., and Peter Heyler, Jr. 1985. U.S. Indus-
trial Robot Forecast and Trends: A Second Edition Delphi Study.
Dearborn, Mich.: Society of Manufacturing Engineers.
iiCommittee on Army Robotics and Artificial Intelligence.
1983. Applications of Robotics and Artificial Intelligence to Re-
duce Risk and Improve Effectiveness, p. 58. Washington, D.C.:
National Academy Press.
i2 Committee on the CAD/CAM Interface. 1984. Computer
Integration of Engineering Design and Production: A National
Opportunity, p. 11. Washington, D.C.: National Academy Press.
i3Shunk, Dan. Integrated Cellular Manufacturing. Paper pre-
sented at the WESTEC conference, Los Angeles, March 1983.
id Computer Integration of Engineering Design and Produc-
tion, p. 50.
i5Ibid., p. 17.
Representative terms from entire chapter:
cad data
