Fast and Flexible Design and Manufacturing Systems for Automotive and Sheet Metal Parts
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The world wide web version of this document is divided into the following sections:
This is the second quarterly report for the MIT/Lehigh University Fast & Flexible pathfinder. Our research team is analyzing product-development in the automotive industry, focusing particularly on improving the management of design information within and between assemblers and suppliers. Our research focuses on developing more fast and flexible communications and processes.
We are six months into a twenty-eight month contract sponsored by the Air Force Wright Laboratory Manufacturing & Technology (WL/MTI) Directorate. Our research has deployed faculty, staff and site-located graduate students from both MIT and Lehigh University at two industry locations: General Motors Saginaw Steering Works Division; and Ford-Louisville Assembly Plant and its primary sheet metal supplier, Budd Company.
The methods being used are process mapping to identify crucial transactions between people and companies, linking transactions to clusters of specific engineering data called features, identifying transactions occurring early in product development that have large downstream effects, and speeding up the processes by providing computer tools and database access that connect people and their transactions to effects such as cost, time, assembly errors, inadequate production capacity, and so on.
Our results affirm the similarities between the automotive and airframe industries. In particular, their complex customer-supplier networks that we call "webs." A working hypothesis is that such a network of companies can improve its performance if participants take pro-active steps during early product design to pro-actively design and manage the web as an integrated system. We believe that "proactive design and integration of the web" is an idea that could be developed with useful procedures, metrics, and supporting software in a way that is similar to design for assembly.
The goals of this research are to:
Migratabilty across different industries is a key goal. We therefore are working closely with the aerospace pathfinder, thus enabling us to begin testing the migratabilty of our emerging concepts.
The next six months will concentrate on developing plans for in-plant demonstrations.
Principal Investigators:
Program Manager
Faculty & Staff
Research Assistants (current)
* Funded elsewhere, however providing intellectual contribution to this research.
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.
These are useful concepts, widely believed to be necessary for business success in the future. Yet few of them have been tested rigorously in a research setting. Our fast and flexible research will contribute to understanding each of these dimensions. Our team will seek to expand the ideas both quantitatively and qualitatively though field studies, development of new analysis methods, and prototyping of new computer tools.
Our continued work has enabled us to refine the problem statement.
Customer-supplier partnerships dominate the landscape of organizational forms for product realization of complex manufactured items. Companies seek partners because the product's complexity generally precludes any one company having all the marketing, design, or manufacturing skills to make them. Partnerships are not new, but increasing competition has put new pressures on them. Also, some striking apparent organizational successes (e.g., Chrysler Corporation) that rely heavily on supplier-partners have influenced some to believe that vertical disintegration provides a path to greater corporate profitability. While such partnership networks offer significant advantages, they are quite complex and need to become more "agile." Improvement opportunities exist for managing time, cost, risk, and quality. Our industrial partners are keenly aware of these opportunities.
We have found that customer-supplier relationships are surprisingly complex: suppliers of main assemblies have suppliers for subassemblies who have suppliers for parts, and all of these have suppliers for fabrication machines, plus suppliers of tools and fixtures to help make and assemble the parts, subassemblies and final assemblies. We have given the name "web" to this set of companies and their relationships. A generic map of a web devoted to designing and delivering complex mechanical assemblies is shown in Figure 1, while a specific one describing some automotive parts is shown in Figure 2. We are in the process of investigating the degree to which companies in the auto and aircraft industries are aware of their webs' complexities and determining the importance they give to documenting and controlling them.[1]
Figure 1. Schematic of the Web Environment for the Case of Complex Mechanical Assemblies. An assembly is designed or partially designed at the top to meet a set of customer requirements expressed as fitup specifications. The design is dispersed geographically and over time, during which new design activities occur, members are added to the chain, and information is lost. Only at the end can the original designer determine if the parts fit, that is, if the original customer requirement has been met. (Developed by D. Whitney from discussions with team members.)
Click here for a separate copy of the above chart, which you can load to your desktop for easier viewing and printing.
Figure 2. The Supply Web for the Ford Explorer Front End. This map shows the parts, fixtures, and their respective vendors and indicates that even for a small number of parts and fixtures there can be a large number of vendors. The bubbles with "$, t, Q" inside indicate major points where money and time are spent to obtain quality. Developed by Mssrs Narendra Soman and Minho Chang.
Click here for a separate copy of the above chart, which you can load to your desktop for easier viewing and printing.
Our hypothesis is that to be agile requires that companies be able to manage this web, not merely survive in it. In particular, we feel that the best way to manage product realization in the web environment is to modify the product realization process so that the existence of the web is taken into account early and is paid careful attention as realization proceeds. We call these steps "pro-active web design" and "pro-active web management." Our project aims to provide tools and methods for pro-actively including web management in product/process design. The tools we have developed or are using are transactions analysis, activity/cost chains, organization maps, key characteristics, and contact chains. These are described briefly below and in detail in other papers at this conference.
As originally proposed, the project aimed to combine two existing techniques and determine if together they could reveal important process improvement opportunities and provide a structured way to implement those improvements. The two techniques are transactions analysis and feature-based design. Transactions analysis is an interview-based technique that reveals how organizations operate by identifying in great detail the entire set of transactions that make up the work of an organization. Interviews are conducted with the people who actually carry out the work. Feature based design is a technique that is the subject of current research. Its objective is to improve conventional geometric design data, such as computer-aided design models, by attaching design intent in the form of constraints, relationships to other features, and non-geometric information such as cost, preferred machine or supplier, importance, and so on. Our field work, described below, revealed that our partners already are using a similar concept called Key Characteristics (KCs). For this reason, we now utilize the terminology KC but the intent is the same.
The research approach comprises four main steps:
Integral to these steps is the development of a set of metrics, in terms of cost, time, first time capability, or other suitable bases of comparison, so that the effect of the pilot projects and computer tools can be estimated.
4 -- Work Accomplished to Date
Among the research's main goals is to demonstrate the effectiveness of transactions analysis coupled with the use of features. This technique has proved very successful. We have formalized this process mapping method in the form of multiple views. These views support capturing information in ways that would support pro-active transactions. The following list of tools identify clusters of transactions, methods of visualizing and managing the web, systematic ways of defining information that is passed out onto the web, and methods of maintaining control over the coherence of that information until the dispersed processes and their outputs converge again as the product is made and assembled.
The tools we have developed or are using are transactions analysis, activity/cost chains, organization maps, key characteristics, and contact chains. Some of these are new while others are extensions of existing research techniques or adaptations of methods being used in industry already. Along with many of these tools we are developing pictorial ways of capturing the information. We call these "maps." Each map shows one view of the physical, organizational, informational, or engineering information being shared by web participants. No single map seems able to show the whole situation.
Transactions analyses are interview-based studies of how organizations operate.[2] Performing transactions analyses at our three partner sites led us to recognize the inherent complexities of engineering partnerships and showed us the need to develop tools to make the complexities visible and deal with them. Transactions analyses reveal where intensive transactions activity occurs and also permit one to see how activities at one point in the process are linked to activities elsewhere. Actual transactions do not correspond to official organization charts or approved information transfers, and the degree to which they differ is a good indication of how the participants must skew the official process in order to make progress. Figure 3 shows a Design Structure Matrix, which is one way of documenting transactions.
Activity/cost chains are an extension of activity-based costing.[3] They are the result of using direct cost measurement techniques during the transactions analyses. In many cases, transactions can be associated with costs, so that cascades of transactions can be linked in order to sum up their component costs. Activity/cost analyses show how much it costs to do some basic activity such as to make a design change, adjust a fixture, or tighten a tolerance. Knowing these costs can help justify improvements in design and business processes. However, most companies do not know their actual costs to the required accuracy and usually compile costs in functionally defined cost centers rather than associating them with processes, especially when those processes cross functional boundaries and enter the web.
Organization maps show explicitly who does what in the web of suppliers.[4,5] These maps turn out to be quite complicated, since assemblies and related tooling seem to be divided up into very small elements and each element is contracted out to a different supplier (at least in the car industry). If companies were to make these maps during early product design, they would be able to plan out who should be in the partnerships and begin thinking about who should do what. Supplier selection criteria could be formulated based on where suppliers lie in the map and what role the play in delivering the final customer requirement. However, it appears that the web grows over time without top level awareness or management. Figure 3 is an example organization map illustrating.
(by Minho Chang)
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This organization map illustrates the expanded scope of our research in response to focusing on information dispersal across the web. The disgram is a depicts all the organizations involved in producing the front end of the 1995 Ford Explorer. Planned January field studies include siting the Ford Technology Center and Ford Tooling suppliers. We are attempting to trace the actual flow of design packages to document where data loss or degradation occurs. This enables us to analyze pro-active methods to improve the integrity of the design data. Successful migration of our results will require validating our concepts within existing supply networks, i.e. web.
Key Characteristics (KCs) are currently in use at each of our three partner companies and at many others.[6] KCs are aspects of the product that require close attention. They are intended to capture customer requirements and express them systematically as design and production metrics. Hundreds of specifications, dimensions, and tolerances typically appear on drawings. The assignment of a KC to a dimension or surface finish, for example, indicates that this particular aspect is the important one to deliver. Different companies have utilized this idea in different ways. GM distinguishes key product characteristics (KPCs), that the customer is aware of, and key control characteristics (KCCs), that the manufacturer must control in order to deliver the KPCs.
Contact chains link the key characteristics of assemblies of parts and fixtures to each other so as to describe how fitup is supposed to be achieved.[7] KCs, for example, highlight visible fits like those around car doors, since fitup dimensions and tolerances are documented by the chains and fitup is a KC for customer satisfaction. Figure 6 shows the contact chains responsible for assuring fitup of the access door of an aircraft engine. A metric we have proposed is to count how many company or organizational boundaries are crossed by a single contact chain. Our assumption is that smaller is better. If companies define these contact chains early in design, they can assign responsibility explicitly to the different suppliers for their roles in supporting the chains. However, it appears that while individual engineers commonly calculate these chains for local assembly fitup analyses, the contact chain concept has not been utilized as a way of unifying the work of several cooperating companies. No current computer aided design (CAD) tools include contact chain representation capability, although the potential to add this capability exists. CAD is commonly used to define parts, less often for assemblies, and hardly at all for assembly fixtures.
Agility Metrics are intended to help companies determine if they are operating in an agile way.[8] [Goldman, Nagel and Preiss] present a list of 100 questions that provide general guidance in this area but a more precise set of metrics is needed. Tools and methods will be developed that relate directly to the web activities we find among our industry partners. These will be aimed at returning quantitative results from measures that are easy to understand and easy to calculate.
In addition to the tools mentioned above significant work has performed in creating a cost baseline of GM Saginaw's product development lifecycle. This work serves as a broad backdrop to the focused cost baselining work to occur at Ford/Budd and Vought.
The next six months will be devoted to detailed planning of three pilots. They are:
The pilots plans are in various stages of development, they are presented here to provide insight into current planning activities.
Pro-Active web Management. The Web pilot will be conducted across both sites. The goal of the pilot will be develop and test methods to pro-actively manage webs. Some observers could suggest current webs form organically. They simply grow as product features are decomposed, sourced and reassembled. However, pro-active management techniques suggest deliberate planning. We plan to develop tools to support the tradeoff decisions that occur during the sourcing process. Effective decision-making will factor the metrics of cost, time, quality (as a function of tolerance) and risk.
We will first develop a highly detailed "web map" at each site. This map will serve to capture the organizations across which products are actually dispersed. This web visualization aid will make apparent the decisions that occur throughout the web and their potential effects. Second, we will develop a web management computational tool that supports trade-off decisions among cost, quality (tolerances), time, risk across web members.
The Customer Requirements Capture pilot will be conducted at GM Saginaw Steering Works. This pilot's premise is that organizational response time, flexibility, and effectiveness can be improved by creating open access to information which is currently locally stored at all points along the "product realization chain". Thus open access will enable decision makers previously unavailable data located at other points in the chain.
For example, if specific manufacturing capability information is available to designers as they make design decisions about new parts, they will be able to more accurately assess customer requirements against the manufacturing characteristics of the "web", through the successive stages of a) sub-component family design, b) design-for-manufacturing, and c) derivation of "Key Characteristics". Access to this information will allow informed decision-making that reflects the organizational capabilities and constraints of the supply "web".
We plan to explore this proposition, and create implementable results by focusing on how the "front end" customer requirements capture process (including: concept formation, bid package preparation, early engineering) can be improved with access to specific manufacturing process information (such as process capability, effective capacity, cost driver information, etc.).
We expect to isolate a set of "features" (KC's, constraints, etc.) that can connect the front end and the back end of the product realization chain. We further expect to define an "information architecture" that will help simplify information accessibility, and can be "ergonomically" fitted to the human organization. Furthermore, this method may shed new light on managing technological innovation in a volatile production environment.
Predictive-Sheet-Metal-Variation Tools will be developed to support the Ford and Budd Company pilot. The goals of the pilot conducted are to a) identify practices to enable flawless product start-up and b) develop predictive/ anticipatory tools to eliminate fit problems.
The approach is to:
Detailed plans are in development currently.
This past quarter has been extremely productive. We have completed detailed as-is maps, using multiple capture methods. These insights have been synthesized and have generated concepts for pilot demonstrations. The three demonstrations that are described above offer three distinct vantage points on the product realization process. The first pilot focuses on the decisions that effect cross enterprise interactions. The second pilot focuses on improving the quality of data used in early product development decision-making. That last pilot offers an in-depth investigation of how to eliminate fit-up problems.
Collectively, the three demonstrations will enable us to develop specific recommendations on how the automotive industry and other industries could more pro-actively manage design details as they are developed, dispersed and integrated into final products.
Endnotes
1. We were introduced to the idea of web mapping by Dr. I. S. Fan and Dr. G. Williams of Cranfield University, UK, who in June, 1994 showed us their research on documenting the "extended development chain" for the A340 wing by British Aerospace and dozens of suppliers. Cranfield's term corresponding to "web" is "Extended Enterprise." [Cooper, et al][back]
2. Mr Martin Anderson directs the Transactions Analysis research on the project.[back]
3. Prof. Manash Ray directs the activity/cost chain research on the project.[back]
4. The work of [Cooper et al] is presented as an organization map.[back]
5. Prof Charles Fine directs the web -related research on the project.[back]
6. Prof Anna Thornton directs the KC research on the project.[back]
7. Prof David Gossard directs the contact chain research on the project.[back]
8. Prof Mikell Groover directs the agility metrics research on the project.[back]