Product Architecture and Modularity

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Product Architecture and Modularity

• Systems Engineering
• MG587
• Karl T. Ulrich and Steven D. Eppinger3rd
  Edition, Irwin McGraw-Hill, 2004.

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Product Architecture Definition

• The arrangement of functional elements into
  physical chunks which become the building blocks
  for the product or family of products.

module
module
Product
module
module
module
module
module
module
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Other terms for Chunks

• A Chunk is made up of a collection of
  components that carry out various
  functions/sub-functions of the product.
• Other terms for Chunks or elements that make up
  a chunk
• Subsystem
• Cluster
• Module
• Building blocks
• Interfaces connect these chunks together.

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Architecture

• The Architecture of a product is the scheme by
  which the functional elements of the product are
  arranged into physical chunks and by which the
  chunks interact.

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Product Development Process
Concept Development
System-Level Design
Detail Design
Testing and Refinement
Production Ramp-Up
Planning
Platform decision
Concept decision
Decomposition decision
Product architecture is determined early in the
development process. This is not a linear,
sequential process.
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Architecture Decisions
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Choosing the Product Architecture

• Architecture decisions relate to product planning
  and concept development decisions
• Product Change (copier toner, camera lenses)
• Product Variety (computers, automobiles)
• Standardization (motors, bearings, fasteners)
• Performance (racing bikes, fighter planes)
• Manufacturing Cost (disk drives, razors)
• Project Management (team capacity, skills)

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How Does Architecture Happen?

• Ulrich and Eppinger Chunks approach.
• MIT Design Structure Matrix.
• Buede Decomposition,
• Physical mirrors Functional structures.
• Dominant Flow Heuristics - R. B. Stone

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Architectures Challenge X
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Modular or Integral Architecture?
Apple iBook
Motorola StarTAC Cellular Phone
Rollerblade In-Line Skates
Ford Explorer
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Modular Product Architectures

• Chunks implement one or a few functions entirely.
• Interactions between chunks are well defined.
• Modular architecture has advantages in simplicity
  and reusability for a product family or platform.

Swiss Army Knife
Sony Walkman
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Trailer ExampleModular Architecture
box
protect cargo from weather
hitch
connect to vehicle
fairing
minimizeair drag
bed
support cargo loads
springs
suspendtrailer structure
wheels
transfer loadsto road
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Trailer ExampleIntegral Architecture
upper half
protect cargo from weather
lower half
connect to vehicle
nose piece
minimizeair drag
cargo hangingstraps
support cargo loads
spring slot covers
suspendtrailer structure
wheels
transfer loadsto road
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Integral Product Architectures

• Functional elements are implemented by multiple
  chunks, or a chunk may implement many functions.
• Interactions between chunks are poorly defined.
• Integral architecture generally increases
  performance and reduces costs for any specific
  product model.

Compact Camera
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Ford Taurus Integrated Control Panel
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Discussion Question

• Is one type of product architecture (modular vs.
  integral) better than the other?
• Performance
• Platforms
• Serviceability
• Interfaces
• Cost to manufacture
• Cost to develop

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Steps to Establish the Product Architecture
Ulrich and Eppinger

• Create a functional model or schematic of the
  product.
• Cluster the elements on the schematic.
• Make Geometric Layouts to achieve the types of
  product variety.
• Identify Interactions
• Fundamental (must interact)
• Incidental

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Step 1 Functional or Schematic Diagram

• Physical and/or Functional
• Connect Elements Which Have Fundamental
  Interactions
• Show Motion Flow

Example Rapid Prototyping Machine using laser
sintering
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Step 2 Cluster Elements into Chunks
Laser Table

• Reasons to Cluster
• close geometric relationship
• function sharing
• modular
• desire to outsource

Control Cabinet
Atmospheric Control Unit
Powder Engine
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Step 3 Produce Geometric Layout
Note If you cant make a geometrical layout then
go back and redefine chunks and identify
interactions
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Step 4 Identify Interactions

• Forces consideration of geometric interfaces to
  accommodate flows
• Illustrates possible problems caused by
  interactions
• Fundamental
• Lines on the schematic that connect chunks
• Usually a well understood property
• Incidental
• Usually not shown on schematic
• Higher order effects/interferences

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Product Architecture ExampleHewlett-Packard
DeskJet Printer
Part of a portfolio architecture and is composed
of parts within a product architecture
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DeskJet Printer Schematic
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Cluster Elements into Chunks
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Geometric Layout
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Incidental Interactions
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Dominant Flow Heuristics

• Heuristic 1 The set of sub-functions through
  which a flow passes, from entry or initiation of
  the flow in the system to exit from the system or
  conversion of the flow within the system, define
  a module.

Energy Material Information
Function System
The Wok Example
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Generic Dominant Flow Illustration
Material
Interface
Energy
Interaction
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Dominant Flow Example

• Fragment of the iced tea brewer FM

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Branching Flow

• Heuristic 2 Parallel function chains associated
  with a flow that branches constitute modules.
  Each of the modules interfaces with the remainder
  of the product through the flow at the branch.

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Generic Branching Flow Illustration
Branch
Module/Chunk 1
Material
Interface
Module/Chunk 2
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Branching Flow Example

• Fragment of the iced tea brewer FM

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Conversion-Transmission Modules

• Heuristic 3 A conversion sub-function or a
  conversion-transmission pair or proper chain of
  sub-functions constitutes a module.

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Conversion-Transmission Example

• Fragment of the iced tea brewer FM

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The Design Structure Matrix (DSM) An
Information Exchange Method
Interpretation Task D requires information
from tasks E, F, and L. Task B transfers
information to tasks C, F, G, J, and K.
Note Information flows are easier to capture
than work flows. Inputs are easier to capture
than outputs.
Donald V. Steward, Aug. IEEE Trans. on Eng. Mgmt.
1981
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DSM (Partitioned, or Sequenced)
Clustering Algorithms

• Note
• Manipulate the matrix to emphasize features of
  the process flow.
• Sequential, parallel and coupled tasks can be
  identified.

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System Team AssignmentBased on Product
Architecture
From Innovation at the Speed of Information, S.
Eppinger, HBR, January 2001.
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Modularity

• Modularity is a product development strategy in
  which interfaces shared among components in a
  given product architecture become specified and
  standardized to allow for greater
  substitutability of components across product
  families.

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Types of Modular Designs

• Slot
• Bus
• Sectional
• All retain a 1-to-1 mapping of functional to
  physical elements

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Types of Modularity with common interfaces
Swapping Modularity
Sharing Modularity
Adapted from K. Ulrich, The Role of Product
Architecture in the Manufacturing Firm,
Research Policy, 1995.
Sectional Modularity
Bus Modularity
Fabricate-to-Fit Modularity
Mix Modularity
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Modular vs. Integral

• Modular

• Integral

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Example of Modularity
K. Ulrich, The Role of Product Architecture in
the Manufacturing Firm Research Policy, 24,
419-440 (1995)
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Example of Modularity
K. Ulrich, The Role of Product Architecture in
the Manufacturing Firm Research Policy, 24,
419-440 (1995)
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Example of Modularity
K. Ulrich, The Role of Product Architecture in
the Manufacturing Firm Research Policy, 24,
419-440 (1995)
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Sony Walkman
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Product Model Lifetime
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About 200 versions of the Sony Walkman from four
platforms!
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From Sanderson and Uzumeri, The Innovation
Imperative, Irwin 1997.
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Platforms and Modularity
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Some Modularity Benefits

• Production of a great variety of end products
  from a limited number of building blocks
• Platform strategy permitting many product
  variants based on a stable architecture
• Facilitate changes to current and future products
• Simplifies parallel testing
• Serviceability
• Allows for parallel development of design teams
• Allows for outsourcing

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Some Limitations to Modularity

• Cannot discriminate look alike products
• Increases the risk of competitors copying designs
• Generally increases unit cost ( more components),
  volume (size) or weight of the product
• More interfaces are less reliable (why??)
• Depends on the capabilities of designers

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Impact of Modularity Decisions on Later Design
Processes
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Product Architecture ExampleHewlett-Packard
DeskJet Printer
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Planning a Modular Product LineCommonality Table
Differentiation versus Commonality Trade off
product variety and production complexity
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Planning a Modular Product LineDifferentiation
Table
Differentiation versus Commonality Trade off
product variety and production complexity
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Supply Chain Issues of Postponing Differentiation
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Examples of Postponing Differentiation

• Paint in Hardware Store
• Cake in Grocery Store
• Your experiences.

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Product Configurators

• Satisfy customer demand by creating a product
  composed of a number of pre-defined components
• Select and arrange parts to fit product and
  operational constraints
• Requirements
• Modularization
• Custom assembly operations
• Up-front engineering and testing

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Fundamental Decisions

• Integral vs. modular architecture?
• What type of modularity?
• What type of interfaces?
• How to assign functions to chunks?
• How to assign chunks to teams?
• Which chunks to outsource?

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Product Architecture Conclusions

• Architecture choices define the sub-systems and
  modules of the product platform or family.
• Architecture determines
• ease of production variety
• feasibility of customer modification
• system-level production costs
• Key Concepts
• modular vs. integral architecture
• clustering into chunks
• planning product families