concurrent engineering definitions

CHAPTER

4

CONCURRENT ENGINEERING DEFINITIONS

INTRODUCTION The concept of concun·ent engineering was initially proposed as a means to minimize

product development time [Barkan, 1988; Evans, 1988; Stauffer 1988; Winner et. al., 1988]. Since then, many interpretations of "concurrent engineering" have emerged in literature. Today, CE is much more encompassing. Expectations range from n1odest productivity improvement to a complete push-button type automation, depending on the views expressed. CE is a paralleled approach-replacing the time-consuming linear process of serial engineering and expensive prove-outs. It is intended to elicit the product develop-

ers, from the outset, to consider the "total job" (including company's support functions). Some common definitions are as follows: Concurrent Engineering is "a systematic approach to the integrated, concurrent design of products and their related processes, including manufacture and support. This approach is intended to cause the developers, from the outset, to consider all elements of the product life-cycle from conception through disposal, including quality, cost, schedule, and user requirements" [Winner et. al., 1988]. CE [Paralleling of (life-cycle functions)]

(4.1)

CE is "a systematic approach to integrated product developn1ent that emphasizes the response to custo1ner expectations. It embodies team values of cooperation, trust, and sharing in such a manner that decision making proceeds with large inter-

vals of parallel working by all life-cycle perspectives early in the process, synchro164

165

Introduction

nized by comparatively brief exchanges to produce consensus." [Clcetus (CERC), 1992; Ashley, 1992] CE""" [Paralleling of (life-cycle functions)+ Consensus+ Cooperation] (4.2) The Computer-aided Acquisition and Logistics Support (CALS) office definition of CE [CALS, 1991] from Military Handbook-59 is "a systematic approach to creating a product design that considers all clements of the product life cycle from conception through disposal. ... CE defines si1nultaneous1y the product, its manufacturing processes, and all other required life-cycle processes, such as logistic support. CE is not the arbitrary elimination of a phase of the existing, sequential, feed-forward engineering process, but rather the co-design of all downstream processes toward a more all-encompassing, cost effective opti111utn .... Concurrent Engineering is an integrated design approach that takes into account all desired downstrea1n characteristics during upstream phases to produce a more robust design that is tolerant of manufacturing and use variation, at less cost than sequential design." CE¢ [Cost-effective robust design (conception through disposal) +Simultaneous design of (all downstream processes 'during upstream phll
~

__ I ____...

Continuous Improvement, Support and Delivery

---.z>

Progressive Enrichment

FIGURE 4.2

Concurrency During Phases of Product Design & Development Process

the different tracks of the development process. These tracks arc mission definition, concept definition, engineering and analysis, product design, prototyping, production engineering and planning, production operations and control, manufacturing, and finally support and delivery. The continuous improvemcnt-"support and delivery" is an ongoing coordination track, which runs for the full life-cycle. This track provides, besides nonnal project management functions, sequencing, cooperation, and continuous support to other tracks. These tracks are not unique to any particular product, and steps (overlaps) may differ from product to product. Once a product is decomposed into a set of tracks, and a traek is decomposed into a set of tasks, they beco1ne one full set of steps leading to product realization. The staggering of their (steps) start points and overlaps is indicative of partial infonnation sharing. Orders are indicative of their precedence. The an1ounts of overlap between two consecutive tasks arc indicative of the degree of dependency that may exist between them [Krishnan, 1993]. If the tasks are completely independent, they all can be aligned along the left tnargin of the diagra1n keeping the precedence intact. The tirne-tomarket in that case would be dominated by tasks that take the longest time to finish. This is a case of a true "simultaneity" or "simultaneous engineering" situation [Garrett, 1990]. The idea of "best concurrency," when the tasks are not completely independent, is to align

Sec. 4.1

Basic Principles of CE

169

each step to the farthest left of the diagran1 as n1uch as possible while satisfying the following 3Ms: I. Maintain the precedence of the tasks that \Vere decornposed. 2. Minimize the horizontal overlap bet1,.veen the consecutive tasks. 3. Maxin1ize the independence of the decon1posed tasks. In general, there is greater affinity and dependence between pairs of activities \Vhich are adjacent to each other. The farther a\vay the activities arc positioned from each other, the lesser would be the degree of affinity or the need for information transfer among thetn. For example, n1ission definition would be rnore closely related to concept definition but would have very little bearing on activities such as n1anufacturing. Similar1y, 1nanufacturing would be closely related to production operations and control but would be less sensitive to tracks such as engineering and analysis. 'fhe arrows in Figure 4.2 represent the interactions between the various tracks. The downward-slant arrows represent the net result of enrichment (a horizontal component) and nel result of needs (a down-vertical con1ponent). The upward-slant arrows indicate the net results of feedback (reverse horizontal component) and net results of consequences and constraints (up-vertical component). A general description of the arrows is given in the Figure 4.2 legend. The concurrent approach is gaining \vorldwidc attention at the 1non1ent. The paralleling of life-cycle activities is being deemed necessary by n1ore and more industries to adapt quickly to changing n1arket conditions and shrinking time-to-market targets. Additional savings tnay come fro1n cost-avoidance--early recognition of possible faults, thereby preventing unnecessary issuance of so ca11ed "change orders" after the product is released.

4.1

BASIC PRINCIPLES OF CE Titning is an important consideration in CE. A lot rides on the tin1ing of making decisions and problem discovery. Approximately 80% of a product's life-cycle development cost is driven by decisions made in the first twenty percent of the program effort [DARPA, 1987; DARPA, 1988]. Concurrent engineering is founded on eight fundamental principles:

Early Problem Discovery: Problems discovered early in the design process (particularly during the first 20% of the cycle tiinc) are easier to solve than those discovered later. Early Decision Making: The "window of opportunity" to affect a design is n1uch wider during an early design stage than at a later stage-when so1ne of the decisions are frozen and when the design is 1natured. Teams often have the natural tendency of making quick and novel decisions, which is good, except those decisions should be lasting as well.

Work Structuring: Hun1an minds cannot practically work on n1ultiple tasks sitnultaneously, parallel computers do. What a human mind is good at is systematically structuring the work or, more importantly, structuring the work-environment-so

170

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that each task can be perfom1ed independently of each other either by a human being, a 111achine, or a computer. Teamwork Affi11ity: Teams of people working in separate groups are likely to create designs, which may be optimal in their individual domains but will seldom ren1ain optin1al in a con1bined dotnain which is a union-sum of those individual domains. Also. teams will have a better affinity if they trust each other. Trusting n1c1nbcrs, if they agree to accept responsibility for a task, prefer to work together rather than in isolation. K11owledge Leveraging: The domain of product design is often very large. It may be in1possiblc to create a general purpose automated or knowledge-based system, which will use appropriate tools and knowledge-driven rules (mostly computerized) to guide decision n1aking. Interlinking decision support tools with spurts of human kno\vledgc-base will continue to be the 1nost viable method for solving complex problems.

Co1nn1on Understanding: Tean1s will work better if they know what other members are doing. This includes operational understanding of all relevant interplay; for exan1plc, what constraints a tean1-men1her would encounter when certain parameters will be changed. Ow11ership: Teams will work enthusiastically to make a good product if they are c1npowcrcd to 111ake decisions in shaping the design and are given "ownership" of what they produce. Constancy of Purpose: Most departments have a natural tendency to make their departments look good to others-create false profits-even though it may be detrimental to the overall corporate goals. The whole corporation will do better if everyone works toward a common set of consistent goals irrespective of the departments they have allegiance to. This requires a change in thinking beyond the goals of one's individual dcpartn1ent or tea1ns to those of the SBU's or the company's goals. The obligation of any supporting unit is not to suboptimize its own goals (such as unit's profit potential or sales) without a clear and direct relationship to the company's overall goals. It must contribute its best towards the system goals. Aiming towards constancy of purpose results in everyone contributing his or her bestworking toward a co1nmon set of consistent goals.

In summary, the benefits of CE stem from the eight basic principles-Early Problem Discovery, Early Decision Making, Work Structuring, Teamwork Affinity, Knowledge Leveraging, Com1non Understanding, Ownership, and Constancy of Purpose.

4.2

COMPONENTS OF CE Although components of CE have not been formally documented, it is purported that it is the environment-spanned by its co1nponents-that yield a significant competitive advantage in product cost, quality, investments, and reduction in cycle time. Components

Sec. 4.2

Components of CE

171

distinguish whether a CE environment would be successful or not. The rewards and satisfaction in CE come from the success of its components. For instance, success of CE depends on the part of those who participate in it. In CE, every participant is expected to contribute lo making the final product: from planners and industrial designers, analysts and detailers, to production engineers and support personnel [Garrett, 1990]. The following discussion describes the basic components of CE.

4.2.1

Multidisciplinary Setup

CE is structured around multifunctional teams that bring specialized knowledge necessary for the program [Owen, 1992]. The multidisciplinary setup-called product development team (PDT)-is composed of several distinct technical sub-units specializing in a variety of disciplines: • • • • • • • • •

Product planners (TPP) Product concept engineers (Tee) Engineers and analysts (Te) Product designers (Tpd) Prototype engineers (Tpe) Production engineering planners (Tep) Management and control (T111c) Computer integrated manufacturing (CIM) and assemblers (T111) Delivery and support (Tds) learns PDTs = U [Tpp, Tee• Tea• Tpd• ~'e' Tep> Tmc• T 11w, and Tds]

(4.8)

Where, U indicates union-of and T stands for " Talents." In the above, nine concurrent teams are intentionally chosen to show the actual correspondence with each of the nine concurrent tracks· of Figure 4.2. Each track is responsible for developing and integrating its own aspect to the product's life-cycle as the program requires. However, there could be as many tracks/tasks and teams as needs arise. For example, experts from the volume production area could be involved in prototype production to identify opportunities to improve process reliability as early as possible. By using this multifunctional team approach to merge design and manufacturing, GE Aircraft engine division reduced design and fabrication lead time for some GE engine components from twenty-two weeks to three weeks. Figure 4.3 shows a bidirectional, sandwiched structure for an Integrated Product Development (IPD) System. In one direction, PDTs are supported by the customers on the top, and the company infrastructure (organization) at the bottom. In a perpendicular direction, PDTs are sandwiched between product and process on one side, and tools and technology on the other side.

=

IPD System U [Customers, Product, Process, Tools, Technology, Infrastructure, PDTs]

(4.9)

Concurrent Engineering Definitions

172

QFD

Customer Require1nents

Chap. 4

Marketing

Strategic, Tactical, and Business Planning

p

Product Development Teams (PDTs)

Product

R 0 D

u T ,,,: Engineering and

T E

Planners

c

p

H N 0 L 0 G

R 0

c E

s s

Assemblers

Mullifunctiona/ Team

SBU

Culture and Practices

Business Process

Education and

Reengineering

Training

FtGURE 4.3

y

Logistics

Finance

Synchronous Manufacturing Organization

Information Technology

A Typical Product Development Team (PDT)-An Example

Where, U indicates union-of and PDT stands for product development team. The infrastructure involves a wide range of disciplines including multifunctional tea1ns, strategic business units (SB Us), culture and practices, business process reengineering, logistics, finance, information technology, education and training, and synchronous manufacturing organization. As shown in Figure 4.3, the custo1ners help establish the requirements for !PD including QFD, marketing, and strategic/tactical business planning. In an IPD sys-

Sec. 4.2

Components of CE

173

tern, PDTs integrate the custotncr's inputs about their product and processes with their own experience in business solutions (tools), knowledge of future directions (technology), and the organizational infrastructure to provide world\vide con1petitivc advantage. The PDTs, which replace the traditional functional department, are often organized along goal-oriented principles. Experts in the field of n1cchanical, electrical, industrial, che1nical, and material engineering, as well as a variety of other fields, work together. Removals of barriers for cooperation and resolution of conflicts are responsibilities of the PDT manager [Deming, 1993]. The dc1nands of today's ever-changing international marketplace are in11nense. Goa1s are 1noving targets, undergoing constant changes and shifting in response to market conditions. The diversity of disciplines in CE is essential to leverage core competency in order to address the growing complexity of today's product needs and global manufacturing trends. CE requires a new approach to project inanagement. Each team 1nust work closely with other teams to identify and develop techniques that are more cost effective, innovative, and sin1ple to use.

4.2.1.1

Promoting the Spirit of Innovation

The n1ultidisciplinary team must work in an environment in which innovative thinking is encouraged and teamwork is rewarded. The spirit of cooperation will encourage the team to use creativity in proposing solutions for difficult manufacturing situations. Suppliers n1ust work with their clients and vice versa to design the manufacturing processes, tooling, equipment, and systems needed to fit the production and plant limitations. They must be selected and involved early enough to participate in the design and other critical decision making processes. By joining efforts with suppliers and partners, aimed at n1eeting the market needs or functions not yet served, everyone wins. Each unit gains the strengths provided by the resources of all the units combined. The custotner gets better service or product at lower cost.

4.2.1.2

Early Supplier Involvement

Not too long ago, companies were reluctant to carve any work to an outside supplier before there was a valid contract establishing tenns of their working relationship. This has since changed with the recent emergence of value managed relationships and long-tenn sourcing strategies. In the early 1980s, with increasing international cotnpetitiveness, profit margins declined sharply. Most of the manufactured products were very complex. It was beyond the scope of a single source (for instance an enterprise or a prime contractor) to design, build, and assemble the complete product. It became obvious fhat close working relationships were essential for the survival of both the product and the companies. Today, n1ost original eqllipn1ent 1nanufacturers (OEMs) recognize this need. They invariably involve the production source during the process of developing the design concept. Adequate expertise and involvement of key suppliers and specialists are vital to achieving the collaborative support required by CE. Good suppliers are capable and interested in participating in fhe development process. They should know and understand their process capabilities as well as their limitations very well and should be able to create an appropriate plan for their production. Early involvement is critical in seeking their vital

Concurrent Engineering Definitions

174

Chap. 4

inputs and in influencing the product's design as it evolves. All participants learn from the joint experience. Suppliers, through this process, get the current business or at least enhance their chances to becon1e the most logical choice for the next 1nodel business. The co1npany gets the early feedback, which might have some useful bearing in selecting other related components.

4.2.2

Synergy and Teamwork

Synergy-that is, combining team capabilities to produce results greater than any individual tcam-me1nber effort-is the cornerstone of any CE organization. Tean1work en1pha~ sizes interpersonal relationships, cooperation, negotiation, and collaborative decision making. For synergy to take root and facilitate cooperation between teams, co111panies need tools that perform in concert The human side of CE plays an important role in making the process work. It is the task of the team 1nanage1nent to keep a balance between the "creativity forces" (such as ernpowenncnt, autonomy, etc.) and the "accountability forces." Creativity forces provide the tea1ns the freedom to do what is right. The accountability forces want those to re1nain within the confines or goals of the organization. There are seven qualities to look for in a CE work-group:

Empowerment: This n1eans giving a design teatn freedom, authority, and the checkbook to get the job done right the first time. The management team must specify the tnajor team goals, budget, and overall design task boundaries to limit their decisions within the organization and product goals.

Staffing: This involves identifying what skills are required for what portion of the work and when to apply them. The success depends on keeping the team of experts lean to start with. Add 1nen1bers to the tean1 \Vhen talents are needed to fit the task. Creating tasks to fit the talents of team-members is a backward process.

Organization: This requires definition of the inajor objectives of the team including team-building procedures (such as decision making mechanisms), brainstorming, and other human-dyna111ics tools. 'fhe team interaction procedure ought to be set in place before taking up staffing or scheduling the tasks.

Leadership: This involves tasks of motivating, guiding, and coaching both the technical experts as well as support personnel. Greater emphasis should be placed on "leading" the teams rather than "managing" them. The leadership role is rotating as opposed to appointing.

Measurement: The team should focus on collectively defining the product development goals. Specific limits exemplified by "X-abilities," such as manufacturability, ought to be set as part of product development goals. The PDT should specify measurements for these goals including developing metrics for each goal.

Autonomy: Autonomy is essential. Management should become involved in project reviews, but let the decision making power lie within the collective responsibility of the assigned teams.

Sec. 4.2

Components of CE

175

• Tech11ical Memory or K11ow-how: It is the responsibility of the technical core team to provide an e nvironment fit to capture the " lessons learned" into some form of technical memory or history files to be used later. The management team must e nsure that this information is archived and re used or communicated to others in the company, including those not directly involved on technical ("how to do") tasks.

In other words, the work-group outcome is a function of these seven quality indicators. ( . JO) Quality of Work-Group= f (Empowerment, Staffing, Organization, 4 Leadership, Measurement, Autonomy, Technical Memory or Know-how) Where, f indicates ''./Unction-of."

4.2.3

Global Participation

The concurrent engineering process for a product development is not a CE process un less it involves all parties that are responsible for its making, regardless of who they report to administratively. Subcontracting companies must be included as participants in the CE teams; at least until the interface design requirements have been determined, evaluated, and are somewhat firmed up. The distributors or retailers often tell the product manufacturers exactly what consumer wants are. The product manufacturers then are able to communicate upstream to the suppliers what parts or materials they would require to manufacture the product. For the organization to function as a unit and for the product to compete globally, all participants have to know what is expected from each other. Strong communication links should be in place. This will ensure a complete integration of the OEM's product needs with supply chain capabilities. With such integration, the subcontractors can influe nce requirements before it is too late. Requirements can be stated in joint terms which the subcontractor can effectively satisfy, and which are reasonably stable and unlikely to undergo any significant change.

4.2.3.1 Inclusion of Outside Trade Partners An effective inclusion of outside (trade) partners in the cooperative development is frequently one of the underemphasized issues related to the implementation of a CE process. In today's environment, because of the growth in the complexi ty of cons umer products and the increased reliance on specialized technologies and methods to manufacture them, partnership has become an increasingly important issue. Companies often rely on outside partners to supply expertise, services, and products in various specialized disciplines. Many examples exist [Womack, Jones, and Roos, 1990): • • • •

Ford and Mazda-Auto Alliance Plant, Flatrock, MI. General Motors and Toyota- NUMMI, Fremont, CA Chrysler and Mitsubishi-Diamond Star, Bloomington, IL General Motors and Suzuki-CAMI, Ingersoll, Ontario

176

Concurrent Engineering Definitions

Chap. 4

• Subaru and Isuzu-SIA, Lafayette, IN General Motors and Isuzu-Luton, UK Toyota vehicles assembled by Volkswagen-Hannover, Gennany In conjunction with the United States Council for Automotive Research (USCAR), GM, Ford, and Chrysler are working to establish volunt.:1.ry parts standards on iten1ssuch as light bulbs, car jacks, radiator caps, switches, handles and other noncompetitive parts-to reduce the influx of parts and boost global competitiveness. Taken to its extreme, this could mean the emergence of a concept called "virtual company," where the

core company has only a limited staff [Kimura, 1994] mostly financiers, who are also the planners of the product ideas. The major workforce is comprised of individuals from various other companies having the appropriate skills to transform the ideas into a useful product. A list of typical participants of a virtual company is shown in Figure 4.4. They

are 1nostly contract en1ployecs. However, they are responsible for delivering the services or products that they arc contracted for, on time and at budget. There is a global partnership between the participants: the product inanufacturers (stylists, designers, engineers,

managers, white-collar workers), process planners (MRP, CAPP), robots/assemblers, machinists (blue collar workers), parts suppliers (vendors, contractors) or materials suppliers (operators, programmers), and product supporters (sales and service outlets, distributors,

schedulers, deliverers, retailers). (4.11)

Stylists, Designers, Engineers,

Parts ~ Suppliers, ~~ Vendors, and Contractors

Managers (Wrute Collar Workers)

~

Material Suppliers, Oper111ors, and Progranuners

Virtual Company

~

Process Planners (MRP,etc.)

Product Supporters

~

Machinist

(Blue Collar Workers)

.-rfl

(Sales and Seivice Outlets,

~

Distributors, Schedulers, Deliverers (JIT), and Retailers)

Robots I Assemblers FIGURE 4.4

Typical Participants in a Virtual Company

Sec. 4.2

Components of CE

177

Where T wc = white-collar workers TPP =process planners

'I.id =schedulers and deliverers Tra = robots assemblers Tbc =blue collar workers Tsop = material suppliers, operators and programmers Tsvc =parts' suppliers, vendors and contractors

U = uni on of It will do little good for a company to adopt a CE environment (or to control its product definition process) without including its trade partners, if a major or significant portion of its production is performed by outside suppliers [Owen, 1992). Establishing a partnership can be strategically very important. IL can eliminate or minimi ze the needs for in-house inspection. By establishing some type of partnership, where the certification program is a part of the deal, one can ensure the delivery of quality incoming materials. In that case, the cost-benefits of inspecting incoming materials and sorting out defective parts for return to vendors must be weighted against the supplier's cost of gelling defectfree incoming parts. A success ful partnership requires a harmonious communication environment characterized by rapid, accurate, and "paperless" business transactions. Other claimed benefits of partnership include greater satisfaction lo the customer, simplified recycling, fewer computer entries, smaller inventories, and greater economy of scale. The increased use of electronic commerce technologies (such as electronic data interchange, or EDI, via wide area networks, value added networks, and electronic vendor bulletin boards) are paving the ways of making partnership seem quite painless. Partnerships are widely used in the auto industry to exchange purchase orders, shipping notices, and payments, particularly with the first-tier of supply-chain partners that deliver directly to OEMs. A first-tier supplier of instrument panels, for example, may be required to deliver product within a few hours of receiving an order, and deli ver it in the assembled order needed o n the assembly line. This close partnership could directly reduce inventory industry-wide.

4.2.3.2 Coordinating with Subcontractors and Suppliers Subcontractors can share the product's life-cycle responsibility via three ways: • Specification and Formal Purchase Contract: One way to share responsibilities with suppliers is via specification and formal purchase contract (FPC). In this traditional process, the customer of his/her own initially creates the requirements. Requirements are passed on to the suppliers (in the specification form) for a quotation (RFQ). The supplier sends back a bid and once the customer agrees with it, the customer issues a FPC or a purchase order. The suppliers design and develop the product as per their understanding or interpretation of the specifications and deliver to the customer the finished product in accordance with the contract. Such work order can proceed in a

178

Concurrent Engineering Definitions

Chap. 4

traditional fashion (see Figure 4.5a) as long as the suppliers are able to satisfy stated requirements and the require1nents are not changed in the midterm. There are two flaws in this n1ethod. First, contractors arc an outside entity looking in. Their positions are no better than two independent internal design groups (in a traditional process) operating at arms' length. Second, since specifications are developed without participation of the subcontracting companies, the chances that they will be able to satisfy the specifications fully and effectively are slim. The quality of the results would be very similar to that of two separate design groups operating at an ann's length. The other eminent danger is that by the time the work is done, it is very likely that the requirements n1ay have to be altered. 1'he two companies doing business in this way must, therefore, include legal and administrative provisions for possible requiretnent changes in the contractual agreen1ent. The change-and-delivery process thus becomes lengthier and 1nore expensive, since it will also involve more administrative-type personnel, and additional administrative chores. Two-phase Contractual Agreement: One of the major flaws of the traditional customer-supplier relationship is that no input is sought before specification is developed. To alleviate this, inanufacturers sotnetitne engage in a two-phase contractual agrecn1ent with their trading partners. First, they enter into a less fonnal agreement during an early definition phase that pennits them to collaborate in product development while still preserving a truly competitive environment. This is called Phase I agrcen1ent. Later, after the requirements are firmed up, a more formal agreement, called Phase II, is signed between the partners. This is shown in Figure 4.Sb. This ensures that the developed specifications can lead to a useful product. However, this type of agrcen1ent can be difficult under a governn1ent procurement. Partnership and Mutual Learning: A third alternative is for customers to include subcontractors and suppliers as partners from the beginning. This is shown in Figure 4.5c. There is collaboration at all levels. By participating as a member of a PDT, subcontractors and suppliers learn how to apply CE tactics in their portions of the product for which they are responsible for. This facilitates the adoption of CE philosophies by the subcontracting companies into the product definitions that both had vested interest in. This also reduces the overall cost and improves quality of the finished product. This type of contractor is commonly known as a "strategic partnership." While auto manufacturers have always set the standard for technology sharing and excellence, until recently long-tenn strategic partnership was not necessarily a part of the package. There is another type of partnership, which is called "tactical partnership." Tactical partners are generally not used for components or technologies that are of "core" type or are "strategic" in nature. The term "core" is meant here to include superior technologies for which the company is distinguished fron1 its competitors and customers recognize. Operational partnership is a third kind of partnership, which is peripheral in nature-meaning least dependent or coupled with the n1ain line of a con1pany's business. Examples include transportation, shipn1ents, raw materials, procurement, purchasing, legal, etc. To realize the 1naximum benefit, it is critical that targets for excellence (TFE) be implemented and uti-

Sec. 4.2

179

Components of CE

FPC: Formal Purchase Contract RFQ: Request for Quote

Customer

Requirements

Specification

7

RFQ

Product ...

Delivery~ Product Develops a product Supplier

(a) Traditional Customer-Supplier Relationship

.-·-.-.-.-.-·-·-.-·-·-·-·-.-.-,-·-·-.-·-·-.-·-·-·-·-·-·-·-·-·-·-! ~

Phase I

Phase Tl

i ;

Pr~l~ary

Bid \

Requirements

!; \

l

)

: 1

,

Sp~ifications

C=:)

Formal Purchase Contract (FPC)

RFQ

I

~ i

i

!_ . - . - · - · - · - · -· - · -. -· - · - · - ·- ·

J___- --· - ·- · - ·- . - -- . - -- -- . - -- -- . - --·

(b) Two-Phase Contractual Agreement Customer

(c) Via Partnership & Mutual Leaming

FIGURE 4.5 Sharing Responsibility with Suppliers

180

Concurrent Engineering Definitions

Chap. 4

lized consistently by all parties of PDTs, the contractors, and the participating suppliers. The U.S. co1npany that has 1noved tnost aggressively in this direction is Chrysler, in part because they rely more heavily on outsourced components than other auto manufacturers [Ohmac, 1989].

4.3

CONCURRENCY AND SIMULTANEITY Concurrency is the major force of concurrent engineering. Parallel work-group [Barclay and Poolton, 1994] was one of the key elements of the concurrency described in Section 4.2. l. Paralleling describes a "time overlap" of one or more work-groups, activities, tasks, etc. Decomposing the product realization process into discrete activities is another essential element of CE. There are seven additional CE principles for which to aim:

Parallel Product Decomposition: Product decomposition means viewing the product realization process as a part of the whole and then overlapping (aggregating) the

deco1nposed sets to recreate or reconstruct the whole fron1 its part. In other words:

Product Realization~ [Decomposing (parts from the whole) ED Reconstructing (whole from the parts)]

(4.12)

The term "whole" also includes multiple characteristics of life-cycle concerns (e.g., X-ability). Although not all life-cycle activities are independent or can be paralleled, many sets can be decomposed safely. For example, it is not necessary to delay the start of an activity if the information required for that activity is not dependent on the rest. Due to increased global pressure to bring a product into the marketplace early, parallel processing in CE is becoming a necessity. There are, however, many ways a product, process, or work infonnation can be decomposed and overlaid in parallel. If a product, process, or work information activity does not affect other parameters or processes, it can be performed locally. If it does, it can be performed in a distributed fashion. Local or distributed processing, to a large extent, depends on how a product structure is originally broken up or decomposed. Do the decomposed parts exhibit independent or semi-independent characteristics? Decomposition allows the scheduling of activities to proceed in parallel. • Concurrent Resource Scheduling: Facilitating the transfer of work information among work-groups is an essential organizational task of any company. Concurrent resource scheduling involves scheduling the distributed activities so that they can be performed in parallel. Paralleling is simple for activities exhibiting independent or semi-independent characteristics. However, it is not so simple for dependent activities. There are many cases when activities are dependent (not yet coupled) but need to be scheduled in parallel with other tasks. A simple case is that of an overlap. Even though a task is dependent on another, there is no need for one to wait until the other task ends. If a task precedes and generates the needed information for a later activity, the next task can start as soon as the needed information is made

Sec. 4.3

Concurrency and Simultaneity

181

available. There is no need to wait for the con1pletion of the fonner task. If the two tasks are independent, they can be scheduled in any order necessary. The other options that address these issues more precisely are: optin1al scheduling (n1inin1izing time, resource, cost, etc.), backward scheduling (1neeting target tin1e), and tearnbased project tnanagemcnt. Sanborn Manufacturing Company employed backward scheduling to set up major milestones consisting of hard and fast dates and worked back fron1 those dates as a planning 1nechanism [Machine Design, 1993]. If product tasks, Ptasks, are independent, a pair of tasks (say task-x, task-y) can start iin1nediately, meaning (4.13)

Start of Ptask-x H Start of Ptask-y

The symbol H n1eans, the tasks coincide with in tiining (starting tilne). P stands for Product, and

... l

(4.14)

Concurrent Processing: In concu1Tent processing, activities are staggered (pcrfo11ned simultaneously or overlapped) rather than carried out sequentially. Keeping track of those con1plcx dependencies that vary \Vith tiine is a critical task in concurrent processing. Appropriate synchronization efforts between different CE teams have to be 1nade. If P 1asks is performed sirnultancously (cotnplete overlap), it itnplies that a pair of tasks can start together, meaning Start of Ptask-i:. H Start of Ptask-v.

(4.!5)

If Ptasks arc overlapped (partial), this means

Start of Ptask-x Start of Ptask-):

(4.16)

Where The sy1nbol

H

means that the two tasks "coincide \Vith" in tin1ing

The notation < means that the first one "starts before" the second one The notation > means that the first one "starts after" the second one

Minimize Interfaces: This entails reducing all sorts of interfaces (product, process and tools) required for the "product realization process" to a 1nini1nun1. Nun1ber of ?interfaces:::? Mini1nu1n

(4.17)

These include the interface relationship between manage1nent and design, supplier interface, design development interface, design manufacturing interface, production interface, etc. Such interface lists can be very long indeed and tend to depend on the size of the company and the product and process complexity,

Concurrent Engineering Definitions

182

Chap. 4

Transparent Co1n1nunication: This provides virtual cominunication between the individual activities that arc partitioned (decomposed).

Tasks

pco1nmunication ~Transparent

(4.18)

Quick Processing: means perfonning individual activities as fast as possible using productivity tools or design aids. It also amounts to speeding up the preparation time in building up the information content before and after an execution of a task. This c1nphasizcs the 1nandate for shortening the pre- and postproccssing time and the time it takes for completing the decomposed tasks themselves. Quick Processing Mini1nize (Lead titne of Ptask-i) for i = 1, n

(4.19)

Where, n is the number of tasks in the P-set, equation (4.14). There is a difference between the complexity of the philosophies (such as product complexity, process cotnplexity, enterprise complexity, or complexity of cognitive behavior), and the philosophies of their management. An organization committed to making such complex products in the shortest possible time need not require an equally complex managc1nent philosophy. An organization can still handle all that while follo\ving a simple management philosophy. This simple management philosophy is the philosophy of decotnposition foUowed by concurrent processing. The concept is similar to what is called the European philosophy of "divide and conquer." To apply this to a complex product, a systc111atic decon1position of the product and process, including 7Ts (talent, tasks, teams, techniques, technologies, time, and tools) is required. In the following, the afore1nentioned seven CE principles are discussed in detail:

4.3.1

Product Decomposition

Smith and Browne [ 1993] describe decomposition as a fundamental approach to handling complexity in engineering design. The t\vo (decomposition+ concurrency) identify activities that can be overlapped or perfonned sin1ultancously. Decomposition and concu1Tency also allo\v one to fonnulate strategics leading to their separation, for exa1nplc, indexing, alternate decomposition, teaming, or restructuring. Let us assuine that an activity has been broken up into tasks: Ptask-x• Ptask-, and Ptask·z' clc. There are four possible ways such tasks can be related: dependent tasks (Pdepl' semi-independent tasks (Psin), independent tasks (Pind), and interdependent tasks (Pint):

Dependent Tasks: A pair of tasks (say Ptask-x• Ptask) is said to be dependent if a task requires information, which is an output from another task. The information required could be a complete output transfer or it may represent only a portion of the output. If the transfer of information is con1plete, they are usually run in a series. This is shown in Figure 4.6(a) • Senii~independent Tasks: A pair of dependent tasks is said to be semi-independent if the transfer of output from one to the other is only a partial transfer (pseudoparallel). The pseudoparallel structure 1neans that there exist weak interactions a1nong

Sec. 4.3

Concurrency and Simultaneity 0I

183 0

I

I

I I

I

I

~JI

I

B-el Ii

TaskZ

I ~~ k-

I

6 {a) Dependel/f Tasks

I i

Overlap

(b) Semi-/11depe11de11t Tasks

FIGURE 4.6

6

0

(c) /11depe11de11t Tasks

(d) lnterdepe11de11t Tasks

Possible Relationships Between Pairs of Tasks

groups of tasks. In Figure 4.6(b), a task Ptask-z is said to be dependent on the tasks Ptask-x and Ptask-y since partial outputs from both Ptask-x and Ptask-y are used to complete ptask-z· • lndepelldent Tasks: A pair of tasks is said to be independent if no portion of the output from one or the other is required for the completion of both tasks. Figure 4.6(c) shows a pair of tasks Ptask-x and Ptask-y that are independent. • lnterdepe1tde11t Tasks: A pair of tasks is said to be interdependent, if a two-way information exchange is required for the completion of any task. Meaning, information from one task (say, Ptask-x) is used to complete the second task (say, ?task) and the information from the second task (Ptask) is used to complete the first task (Ptask-)· This is shown in Figure 4.6(d). In other words: ptasks = U [Pdep• psin• pind• pint]

(4.20)

The symbol U implies "union-of'. Paralleling tasks and the amount of overlap depends on the types of relationship and the degree of dependency between them. The overlap between two intermediate tasks or specifications/outputs represents the time lapse to build the information required for the start of the subsequent tasks. Coordinating tasks that exhibit dependent or independent characteristics are quite straightforward. The dependent tasks are arranged in series and independent tasks are stacked in parallel. For the work-groups, however, the challenges of CE are extremely difficult when many tasks are interdependent; meaning they are coupled and cannot be separated explicitly either in a series or in a parallel mode. Interdependent (or coupled) tasks take more design time and many iterations (of information transfer back and forth) before they finally converge. CE strives for simultaneity and immediacy. In practice, however, mutually independent group of tasks seldom exist. Strategically, de-

184

Concurrent Engineering Definitions

Chap. 4

composing the interdependent tasks into a series of dependent, independent and semiindependent tasks can reduce the size of the working groups and the number of iterations that are required to obtain a reasonable solution. (4.21)

Where, symbol U indicates "union of'. Both of these steps can have a significant impact on reducing the time-to-market aspect. Furthermore, minimizing interactions between

various tasks leads to more overlap and less preparation (build-up) time between the tasks. This could yield additional time reductions. Similarly, the composition of pseudoparallel structures out of a large number of semi-independent tasks enhances concurrency. The semi-dependent and independent tasks are discussed in this Chapter. The strategies for dealing with coupled and dependent tasks are discussed in Chapter 8, Volume I.

4.3.2

Concurrent Resource Scheduling

Frequently, the "product and process" is radically redesigned to achieve parallelism [Costello, 1991]. Paralleling of activities provides management teams with opportunities to reorganize and control the resources applied during CE. These resources fall into three main categories: teams (for example, people, tnachines, facilities, outside firms); tasks

(activities or projects they work on, knowledge of the projects, information they need to work with); and time. The trio provides a basis for defining a work breakdown structure (WBS). A WBS is really a series of interrelated work tasks initially set in motion by the planning track. New tasks are added or created by the subsequent tracks when put into motion. The latest series of tasks are mostly due to the support and delivery track. These tasks are over only when that product is finally disposed at the end of its useful life. A good WBS contains all three elements: paralleling of tasks, paralleling of teams (workgroups) and optimal time schedules. It uses as much knowledge as possible, which aggregates the existing evidence for concurrent work scheduling and tasks' decomposition that designers commonly use. Techniques such as optimal resource planning, cost accounting,

level balancing, OPT, and other load management approaches are considered integral to WBS in achieving concurrent resource scheduling. The types of WBS required within an organization dictate how 7Ts should be developed and used. Figure 4.7 also shows how CE activities and work-groups should be organized into loops, linked (electronically connected) together by a product/process hierarchy (PtBS/PsBS). The product decomposition details have been integrated into such loops. Concurrent resource scheduling is shown in Figure 4.7 as a central block, where arrows to and from the nested loops or decision blocks either emanate or terminate. The outer loop starts with the multiple perspectives of design and the innermost loop ends with multiple analyses (or projects). There is a series of nested loops to prune the elements or the information envelope required to build a total product or process model. One of the purposes of resource scheduling is to leverage the adequacy of a good supply system. Supply systems establish teams of organizations and processes, including inanufacturing partners, vendors, distributors, transportation, delivery, and sales.

Concurrency and Simultaneity

Sec. 4.3 Baseline System

Definirion

Updale

185

Adjust or fine-tune the requirements,

Generation

if necessary

Multiple Perspectives of Design yes Hierarchical breakdowns of Process Tree (PsBS) Hlerarchical breakdowns of Product Tree ~(P;:'IB~S;f;)'--;_,..