MIT Lean Production research is established in the International Motor Vehicle Program and the Lean Aircraft Initiative. The research objectives are to learn, synthesize and disseminate the tenets of Lean Production. Some observers in industry and academia believe the best Lean practices will form the foundation for a next-generation paradigm bearing the name Agile Manufacturing.
The Agile Manufacturing Enterprise Forum at Lehigh University has defined agility along four dimensions.
- value-based pricing strategies that enrich customers
- cooperation that enhances competitiveness
- organizational mastery of change and uncertainty
- investments that leverage the impact of people and information
The US national manufacturing technology infrastructure is challenged to transform itself from a lethargic Cold-War, defense-dollar-driven machine to an agile worldwide competition-capable machine. This transformation will only be accomplished by the infusion of new ideas and adoption of business practices.
We have a long-term vision of developing the framework and tools for a new product-development information and computational infrastructure. This infrastructure would serve as the intelligent information highway for complex, multi-organizational manufacturing systems. We view this extended manufacturer-supplier system as a web. The web encompasses not only the respective organizations involved but also includes the assembled products and the shared processes.
Managing the web to support the required improvements is our challenge. Given the complexity of the web, we are concentrating on the area of transferring design information in the product-development process -- from requirements definition through production and modification.
During the "product-development" process, technical objectives are communicated through a mix of verbal, paper, and electronic media. This applies to communication between military prime contractors and their multi-tiered suppliers, and between commercial end-users and the production supply chain. Problems occur because different design process members pass incomplete or possibly ambiguous data to each other. Hence there are a series of steps and missteps.
Data uncertainty plagues manufacturers throughout the process. As a result, one sees highly iterative communication flows, near institutionalized rework, or unidentified and therefore unmanaged cost drivers. Individuals and departments must continually posture to "make the best use of the information" with only informed guesswork. Our as-is process mapping has documented these problems during requirements definition, initial product design, launch of production, and during design modifications and corrective action procedures in all three sites.
Multiple reasons explain these inefficiencies, in addition to data uncertainty. A current fundamental problem is the lack of a single CAD/CAM system or standards in use. As it is, no one system offers the required breadth in accomplishing required tasks spanning from design to assembly. Likewise, the lack of industry standards compounds these inefficiencies. And, no practical standard is foreseeable, despite ongoing efforts. The lack of a CAD/CAM system or standards introduces a variety of potential problems, such as:
- Difficulty in capturing qualitative and multi-dimensional customer
requirements in a standardized format;
- Ambiguity in specifying design details, such as standard tooling reference
points, tolerances, assembly instructions, etc. ;
- Need for suppliers to augment incomplete designs to account for their local capabilities.
Finally, the problems created by the above circumstances become acute where technical and business processes intersect. For example, at many points during the development or modification of a product, trade-offs must be made between technical and financial factors. Poor or narrowly defined data systems restrict the ability to consider financial and technical factors simultaneously. Too often products are modified for cost reasons in a way that inhibits technical performance. Or, sometimes trade-offs are made without good information, thereby degrading both cost and technical dimensions.
In even the best companies there are business and engineering practices that can be improved. Being fast and flexible is our way of describing better processes generally. The MIT/Lehigh automotive and aircraft Fast and Flexible Pathfinders aim to improve methods of transferring design information along the supply-chain, in these and other industries.
Three companies are helping the research process by providing on-site access and data. Vought Aerospace, a first-tier aircraft subsystem supplier, is our aircraft partner. And supporting our auto pathfinder are GM - Saginaw, a first-tier component's supplier, and the Ford - Louisville assembly plant (LAP)/ Budd company team. LAP is the final assembly for the Ford Explorer, and Budd provides approximately 80 percent of the required sheet metal.
At each of our three sites we will document the "as-is" state of the relevant portion of the product development process, and identify high impact problems and develop suggestions for process improvements.
We determine the relevant portion by placing greatest emphasis on those problems occurring during design information transfer. Although they occur during transfer, the problems surface while trading off business and technical issues. This determination will draw attention to particular types of problems where we believe major improvements in the product development process are possible. Proposed solutions for some of the existing process or data-system problems will be selected for in-plant test or simulation.
To examine the meaning of fast and flexible and to examine the four principles of agility, we have formed an approach to improving business processes. To determine the processes executed to design or redesign existing products, several components and assemblies were selected for exploration. Assemblies are inherently integrative: they bring together multiple processes, and people. They are especially useful for highlighting transactions and process problems. These assemblies are being used as a conduit for the following three components of the research:
- 1. Process mapping: Documenting the transactions (exchanges of
information and material) that constitute the relevant portions of the
product-development process is a prime concern. We have chosen methods for
process documentation using two display formats -- process flow charting and
design structure matrices. We are likely to develop other formats to capture
the variety of data types in use. The results of these efforts will allow us
to:
- a. Link organizational transactions to clusters of specific engineering or process data: We and our industrial partners call these clusters "Features," "Key Characteristics," "Significant Characteristics," "Key Product Characteristics," and "Key Control Characteristics."
- b. Identify transactions that do not add value: Such transactions either carry no new information or because they exist due to defects in the process. Examples include error-correction, "problem-solving," requests for clarification, or attempts to increase confidence in some other transaction.
- c. Identify missing transactions that should be included in a more robust process: Examples include feedback from field use of previous product generations; information that should flow among remote sites; or early identification and definition of information that will be needed later in the process (e.g., testing protocols).
- 2. Evaluation process: At each site, targets for improvements are
likely to be different. The research focus will therefore be determined as we
evaluate our observations and identify specific improvement opportunities. Two
categories of interest are:
- a. Process improvements: We strive to find areas where changes in organizational processes may improve speed and flexibility. Extension of concurrent (non sequential) process requirements, for example, capture methods across prime contractor/assembler and suppliers.
- b. Information system support tools: We will seek out computer tools or database access tools that streamline transactions. Computer improvements could directly link features to transactions, permitting better or faster transactions to be carried out.
The project is now three months old. Nine graduate students, supervised by our team of faculty and staff, have concluded summer research activities at three industrial partners' sites. The observations recorded below reflect hundreds of interviews conducted at each site. Initial mapping of the "as-is" condition for each site is underway. A description of the sites and their salient characteristics follows:
4.1 General Motors - Saginaw Steering Division:
The GM-Saginaw Division makes a wide variety of precision and heavy duty assemblies for a large number of customers. The components evaluated during our research include the intermediate-shaft and half-shaft product families. Saginaw is the leading intermediate-shaft supplier in the world market, with a share of 14 percent. It is the largest North American supplier of half-shafts and is second in the world. GM-North American Organization (GM-NAO), its largest customer, accounts for over three-fourths of the output for both product families. GM-Saginaw provided the opportunity to conduct a wide product development transaction's analysis. Our research team was able to gather data spanning Saginaw's operations.
Production rates vary from custom to mass. For example, the average daily production range for specific half-shaft designs is 146 to 5565 units per year. Different domestic and foreign customers provide design requirements in a full range from vague requirements to fully dimensioned drawings and process plans. Even GM-NAO will often have a fuzzy set of requirements, depending on how early Saginaw is brought into the process for a pending product program. In contrast, Toyota's North American NUMMI plant provides Saginaw a build-to-print drawing.
Saginaw must therefore maintain a variety of customer-response processes ranging from performing a complete design to building to print. Saginaw has adopted a strategy of developing variant designs for new customers and vehicles. Hence they have a completely customer-driven product-family set, which is leading to downstream challenges.
Early transactions analysis of Saginaw systems indicates that the customer requirements-definition process is crucial to Saginaw's overall speed and flexibility. Saginaw is directing efforts to increase its non-allied (i.e., non-GM) customer base. Currently, Saginaw must estimate design and manufacturing parameters without detailed information at early points in the requirements-definition phase. Their efforts to expand market share will likely intensify this situation. With enhanced data tools linking customer requirements, component design and manufacturing capabilities, Saginaw will be able to more swiftly and thus effectively handle increases in the variety of products dictated by new customer markets.
Among Saginaw's main challenges is managing product family proliferation and its impacts on their manufacturing operation. Saginaw's current manufacturing strategy is being challenged by its own goals and market pressures. This strategy includes deploying flexible (e.g., NC-controlled) machining equipment in dedicated (single customer or vehicle) operating modes. This enables predictable output for each customer. But it can simultaneously constrain otherwise flexible equipment by not making use of its swift-change capability. Some dimensions of this manufacturing strategy may also constrain total capacity and therefore organizational flexibility. As the proliferation continues, minor differences between components will at times create manufacturing bottlenecks. Simple design changes, i.e. a 2 mm expansion of a joint, may have unforeseen tooling impacts. Unless predicted during requirements definition, such effects will occur late in the product development process after significant capital investment has been made--a costly and inflexible outcome indeed!
While Saginaw has a great deal of experience dealing with traditional product and process technologies, new demands are challenging Saginaw to design and deliver components using different materials (e.g., aluminum) and processes (e.g., increased need to outsource materials due to lack of capability). It must now use its existing plant and design staff more efficiently, thus enabling itself to balance current design and manufacturing capability with increased non-GM business. Saginaw is also compelled to reassess the adequacy of current skills and capabilities. All of this is happening while the company is aggressively seeking to generate new business.
The research team has gathered process and feature data that will permit them to map the traditional engineering response for the entire range of customers as well as to account for the costs of the transactions in these processes.
Vought is a full-service first-tier supplier of major aircraft subsystems (e.g., 747 tail section) to both commercial and military programs. It has developed specific market niches in aircraft tail assemblies and nacelles. Its portfolio of programs includes various subsystems for the C-17, B-1 and B-2 military programs, and the Boeing 747, 757, and 767 commercial jets.
The aerospace industry is characterized by a low annual production volume, but has long-lived programs. The Boeing 757 has been in production since 1980 Vought has delivered a total of 620 tails. The industry consolidation trend is accelerating, driven by the declining defense budget and a changing world market. Examples include Northrop-Grumman Corporation's recent acquisition of Vought and Boeing's outsourcing of 777 assemblies to Japanese companies. Political pressures, such as local content, are also redefining the market.
Ongoing transactions analysis at Vought is focusing on the corrective action processes on established programs. The transfer of design information is also being examined. We have selected three components across three different aircraft to assist in analyzing Vought's processes and capabilities.
The first component is the Boeing 747 plowshare, located at the mating of the horizontal stabilizer and the tail section. This complex assembly has had manufacturing responsibility transferred twice, but design changes have been persistent since the part was introduced. Boeing made it for five years, then transferred it to Vought. Then, 20 years later (in 1993), Vought transferred it to a Japanese subcontractor, Shin Meiwa.
The second component is the Boeing 757 tail-section bulkhead, a structural element that carries about half the load of the rear-vertical fin. This bulk-head section has provided us an insight into several domains, such as fit-up problems, preliminary application of Key Characteristics, and corrective action processes.
The third component is the C-17 engine nacelle, a complex assembly containing thermal, fuel, electrical, hydraulic and mechanical systems. This part also contains components supplied by lower tier suppliers. The nacelle is one of the few instances of a technology leap (i.e., core reverser capability) on the C-17 aircraft. It has provided us with critical insights on tolerance chain management, corrective action processes, and design iteration drivers.
These three components, along with a cursory exposure to the Gulfstream V design methodologies, have provided an excellent vantage point for examining Vought's manufacture-modify processes. Corrective action is an important portion of this process.
We are unsure which is the greater compounding factor impeding permanent corrective action: long programs or low production volumes. On both commercial and military programs Vought has experienced persistent fitup problems over the years. Reasons why permanent solutions were not implemented vary. In some cases the original design was incomplete. Vought is not always able to obtain the authority it needs to make necessary changes. In other cases there is not enough production volume to justify effective but costly solutions.
Vought noticed nacelle fitup problems on the second (set of four nacelles) aircraft, and it is now working on aircraft 22. The Boeing 757 tail section has a twenty- year history of initial fit-up difficulty that has only been solved by custom fitting the tail to the fuselage. We have characterized the problems as primarily rooted in dimensions and tolerances of parts and their associated fabrication and assembly tools and fixtures, with errors of 0.5 mm to 3 mm being pursued with vigor.
These details of the problems are not our focus, rather we are suggesting that the system costs of fire-fighting teams developing solutions to symptoms -- not root causes -- are inadequately understood. The combination of technical, political and business issues, perhaps, creates a disincentive for identifying and correcting the root cause.
The systems-integration responsibility often delegated by primes to Vought exacerbates fitup issues. Vought is held accountable for suppliers they select and suppliers directed by primes. However, Vought does not always participate during the initial top-level designs. This was the case on the C-17, where the prime contractor elected to retain all design responsibility and distribute assemblies for manufacture by many suppliers (currently 27 first-tier suppliers). Our research found that the mating of the C-17 pylon, engine and nacelle, each manufactured by different sub-contractors, demonstrates the challenges of integrating assemblies distributed to different suppliers. This fitup problem is a typical instance where downstream impacts of upstream decisions are not adequately understood and prove to be costly to fix.
Two facts must be faced: First, these older programs will continue, and their problems will therefore continue until they are solved. Second, it has not been proven that modern computer methods are yet capable of eliminating these systems integration problems.
In response to these problems, Vought has launched an aggressive program of innovative design methodologies and proactive use of the key characteristics that it is applying to a commercial product. Vought's goals are to try to standardize and streamline the design of parts, assemblies, and fixtures so that less effort is required in problem solving and more parts fit together the first time. Our team has documented transactions describing the original design and launch of three older assemblies as well as the problem-solving transactions that have been developed in response to the dimensional issues encountered. They have not yet had access to the most recent programs due to their commercially sensitive nature.
4.3 -- Ford Motor Company and Budd Company
The Explorer is the #1-ranked sport-utility vehicle, capturing 25 percent of the US market in 1993 data. Despite having one of the fastest assembly lines in North America, each of the 1690 cars produced per day is pre-sold. Ford's practices are driven by the need to keep up with the demand. According to Ford, manufacturing capacity is the dominant constraint in capturing increased market share. They are currently bringing a second Explorer facility on line. Ford is in the midst of launching a new model of its successful Explorer, with most of the model changes being new front-end sheet-metal body parts.
The Ford-Louisville Assembly Plant has changed from producing a mix of light-truck platforms to exclusively producing the Explorer. During this time, the Budd - Shelbyville Plant was built in 1987 to support the 1990 Explorer program. Eighty percent of the Explorer sheet metal is provided by the Budd plant, only whose site is 30 miles away. Important sheet metal fabrication and assembly tools and fixtures, however, are made by other suppliers.
Our team has selected inner- and outer-fender panels to examine design and manufacturing problems encountered during launch. Launch is an intricate process because it is being accomplished while the existing model is still in production -- a process called an "integrated launch." Launches are commonly performed in serial changeovers.
Launch is the last phase of a forty-eight month refreshening (minor style changes) schedule. The launch process typically requires a team of engineers about several months. Ford's goal is to cut this time in half. In order for Ford and Budd to shorten the launch period significantly, however, they will have to improve the original definition of parts and fixtures (the part designs are already 100 percent on computers) and increase the completeness and validity of information packages that are exchanged between designers of parts, fabrication tools, assembly tools, and measuring equipment. A basic component of this challenge is to increase information traceability and enable root cause analysis. The students have documented the design processes that generated the original parts as well as the problem-solving activities occurring during the launch process.
Despite all parts being designed on Ford's proprietary Product Design Graphics System (PDGS), fit-up problems persist. A focal activity in any new vehicle launch is the discovery and removal of fit-up errors among the parts. These errors, like those in aircraft, range from 0.5 mm to 3 mm. There are many sources of error, and they are similar to those encountered in the aircraft industry: inherent variability of material properties; inaccuracy of fabrication and assembly fixtures; errors in the original design process of parts and tools; and omissions or errors in transmitting design specifications or information among the various suppliers of parts and tools. To address these problems, Ford and Budd have developed a problems-solving diagnostic, characterizing causes to be either design, quality or tooling. They jointly undertake problem solving efforts. Ford's Explorer output rate incentivizes rapid identification and correction of problems.
At all three sites, researchers have completed draft maps of the relevant portions of the product-development chain. At Saginaw, we have covered the broadest part of the development process -- from early customer contact through mature products in production. At Vought, we have covered a different portion of the development process for each component studied. On the C-17 we have charted from early program development through low rate initial production parts. And on the Boeing components we have looked at modification of an older designs. At Ford, we have taken an in-depth view of the development process -- the launch of new sheet metal in a mature product platform.
The net result of our early mapping gives us sample transactions that cover the strategic view (i.e., how to respond to different markets) of product development, enabling us to connect the microscopic details of production and tooling design (e.g., how to create a single predictable weld by combining appropriate sheet metal design, tooling, and welding process characteristics).
The value of this mapping is that seemingly "small" details -- such as the edge of a sheet metal radiator bracket, or a 2 mm change in a steering component, or the subcontracting of a single aircraft component to Japan -- can be understood in the larger context where speed, cost and flexibility are determined by the combination of many details. Furthermore, these seemingly "small" details sometimes spawn "hidden" activities slowing development times and reducing flexibility, while increasing costs in a way that is hard to detect.
Our early maps point out several clear areas where "transaction" intensity is high, and where improvements are therefore likely.
- * Requirements definition: At Saginaw and within Vought's C-17 program, there are clear linkages between the requirements-definition stage of product development and the downstream definition of product and tooling. This link defines the speed of development and the ultimate flexibility of the production process.
- * Moving from design toward production launch: There is a big "bump" of activity at this point at most sites. And, as shown in our deep look at Ford's launch, the activities iterate back "upstream" to design and "downstream" toward tooling qualification.
- * Moving out of the assembler / prime contractor into the supply chain (product and tooling chains): As designs are passed out across the web of parts, suppliers, and processes, the amount of system-wide transactions increases dramatically, often "hidden" from obvious view. Data integrity issues loom large here.
One major early finding is the large number of transactions that do or should "feed" back up the chain from downstream organizations. We noted that suppliers have indicated that they need to pass considerable information back upstream to assemblers, or that they wish they could but were blocked from doing so. It is also clear that data integrity is a crucial issue here, and therefore this represents a candidate for data support tool enhancement.
Process mapping is now moving from the draft stage, to a deeper definition of "hot spots" such as the expensive engineering and tooling changes associated with seemingly small product engineering modifications.
The three corporate sites present us with a rich variety of situations, permitting us to compare their responses to remarkably similar problems. These problems may be expressed in the following unifying themes:
- Parts, assemblies, tools, fixtures, and equipment are procured from a web of
suppliers. Information is lost during transactions within the web. This is
still a complex problem in spite of recent efforts by companies to
reduce the number of suppliers.
- Large amounts of money are spent on tools and fixtures but errors occur
during assembly anyway. This appears to be true whether or not there is a
digital definition of the product.
- A huge amount of knowledge is needed to describe and execute the processes to
make these complex assemblies. This knowledge typically resides
unsystematically in the heads of the people rather than in an organized
database. A significant number of transactions are directed towards repeatedly
locating and organizing this information.
- The transactions that occur (or do not occur) at the beginning of the design
process have a disproportionate influence on the later stages -- where we
believe many problem-solving transactions could be avoided. Many of the
missing transactions involve better understanding the customer's needs and
specifications as well as matching the supplier's capabilities to those
needs.
- Each site has a "Key Characteristic" (KC) concept intended to focus attention
on aspects of the product that are important to the customer. These KCs could
be defined systematically and proactively to meet pre-defined customer needs.
At present they are not. Making major improvements in speed and flexibility
through the use of KC's has tremendous potential.
- Significant amounts of time and money could be saved if things worked
correctly the first time. "First time capability" is a powerful metric that
measures the contributions of many supporting process improvements.
- At all the sites, both speed and flexibility are impaired by large inflexible
tooling, fixtures, and machines. The potential exists for designing or using
these items more flexibly.
- Many opportunities for product development improvements are already known to
the companies. Justifying their apparent cost, though, is difficult because
the cost penalties associated with the present processes are dispersed over the
web of suppliers and are therefore almost invisible.
- The root cause of a problem is rarely found early because the information needed to determine it is dispersed over this web and therefore almost impossible to assemble coherently.
7 -- COMMON AUTO AND AEROSPACE CHALLENGES
Our list of unifying themes arose from the summer activities at our partners' sites. These themes are examples of more generic activities and challenges that apply to many industries. We expect that our findings and process analysis methods will focus on several of these challenges and form the basis for migrating the results to other industries. These challenges are:
- Managing core competence and corporate knowledge: Given that parts
and manufacturing facilities are procured from a web of suppliers, each company
in the web must define what it does best and what it should outsource. What a
company develops in-house comprises its core competence, but it must also
understand what it buys well enough that it can write competent specifications.
Otherwise partners will be unable to deliver information or material things to
each other that are right the first time.
- Performing intelligent make/buy product decompositions: Deciding what
to make and what to buy involves breaking down or decomposing products and
processes into parts and classifying them intelligently according to how easy
it is to describe them to suppliers. Parts and assemblies that are too hard to
decompose cleanly and describe crisply should not be outsourced. Similarly,
the ability to decide what makes a competent supplier for a given kind of part
or process is necessary for a successful partnership.
- Expanding use of digital definition: It is known that a digital
definition of parts and assemblies greatly reduces the amount and range of
errors that occur when vendor-supplied parts are assembled. However, errors do
persist. Moving to the next steps, namely bringing tooling and equipment under
digital definition and coordinating their design with the design of parts and
assemblies, is necessary. A quantification of what types of errors remain even
in the current digital environment is required. In addition, an
information architecture is needed that will capture and organize the
interrelated information so that it can be passed around the web and understood
completely at each node.
- Linking processes and design features: Transaction analysis and
feature-based design are already proven techniques in limited domains, but
their potential for individual growth and growth in concert is still
unexplored. Better processes linked to specific design features (tolerances,
dimensions, measurement points, KCs) clearly will improve problem solving and
first time capability.
- A wider range of computer tools is needed to support these activities. These include methods for defining and displaying transaction maps; ways of defining features and keeping them persistent in data bases as they are passed along the supplier web; definition of chains of tolerances that define assemblies of parts and fixtures and maintenance of chain coherence and consistency up and down the web; and systematic methods for defining and quantifying KCs.
8 -- THE WEB OF PARTS, ASSEMBLIES, TOOLS, FIXTURES, CUSTOMERS, AND SUPPLIERS
Of all the themes listed above, the one that appears to have the most potential for giving visibility to the migratable concerns is the web of customers and suppliers which is composed of assemblies, tools, fixtures, and processes. This web is the dominant feature of all our partners' systems and the source of most of the transactions we have documented. In any "Agile world" such webs will play central roles. So improving their performance has high priority.
We have identified several ways of viewing this web: The physical map of the product (Figure 1); the process or transactions map of activities (Figure 2), and the organizational map showing the players in the web and the items (materials or information) that they exchange with each other (Figure 3). Documenting each of these maps for each of our partners' sites is one of our immediate next steps.
Figure 1. The Physical Map of Parts, Assemblies, and Fixtures
The physical map documents the parts, how they assemble to each other, and how their tooling aids fabrication and assembly. This map identifies all the important KCs, mating features, dimensions, and tolerances required to guarantee quality and proper fit during assembly. Furthermore, it permits all the tolerance chains responsible for final fit to be visualized. Associated with each link in the configuration diagram is information on the mating features, the tolerances, important places to make measurements, instructions for performing the assembly, the names of people and vendors involved, and so on.
Figure 2. A Design Structure Matrix, a method for mapping transactions
The Design Structure Matrix (DSM) is one of many ways we are exploring to capture transactions information. The DSM is especially suited for identifying clusters of related activities as well as pointing out places where the process is likely to repeat a chain of activities. It is able to capture in one diagram a large set of complex relationships and enables the viewer to rapidly understand a complex design process. However, the DSM is weak at capturing processes that branch depending on conditions encountered during the process. It is also unable to express the passage of time conveniently. While Figure 2 uses Xs to capture relationships between activities, one can use numbers to represent the strength of the relationship.
Figure 3. The organizational map, showing materials and information exchanges
The organizational map shows the flows of information and material between organizations in the web of suppliers. The physical nature of the items being exchanged is captured in the physical map of Figure 1 while the informational relationships are described in process maps like Figure 2.
Each of these representations is a "view" of the web, emphasizing different aspects. These views share a great deal of information and present it in different ways. Figure 1 is the closest to traditional CAD geometry-based representations, but it fails to show the information interactions of Figure 2 or the business relationships of Figure 3.
In the next three months we will finish making as-is maps of the target assemblies at each of the sites, documenting them in the forms indicated in Figures 1, 2, and 3. Expressing the findings in these multi-view ways will permit us to highlight the relationships between transactions and features. As these relationships become more clear, we will be able to identify improved processes and describe them in terms of more clearly focused features or KCs as well as more efficient transactions.
A second output of these activities will be our first steps at defining common feature sets and common kinds of transactions observed at all the sites.
While issues like these are being explored, we will also be searching for existing software that could be used to represent any of the three types of maps in Figures 1 - 3.
As an example of where our work might lead, we have found that the C-17 nacelle's fitup can be represented as a set of tolerance chains extending through a set of suppliers. If each supplier understands its role in the tolerance chain, it is more likely that fitup will improve. Our diagramming methods for capturing transactions could help them gain this understanding. Longer term, early identification of tolerance chains during design may help members of a supply chain to identify their responsibilities in terms of standard reference points on the parts they supply. Such reference points could be identified as KCs and could act as the interfaces through which both the parts and the suppliers interact. Finally, computer tools might be developed to help designers anticipate problems that will arise when different parts of a complex assembly are procured from different suppliers, permitting the design process to anticipate supply chain problems from the beginning instead of reacting to those problems.
This way to the Agile Manufacturing Program at MIT
This way to the Center for Technology, Policy and Industrial Development
Mail comments to the Agile mailbox. Last modified: 10/III/95