Product Architecture and Modularity Systems Engineering MG587 Karl T. Ulrich and Steven D. Eppinger 3rd Edition, Irwin McGraw-Hill, 2004.

Product Architecture: Definition The arrangement of functional elements into physical chunks which become the building blocks for the product or family of products. Product module

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.

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.

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

Architecture Decisions

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)

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

Architectures : Challenge X

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

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 KnifeSony Walkman

Trailer Example: Modular Architecture box hitch fairing bed springs wheels protect cargo from weather connect to vehicle minimize air drag support cargo loads suspend trailer structure transfer loads to road

Trailer Example: Integral Architecture upper half lower half nose piece cargo hanging straps spring slot covers wheels protect cargo from weather connect to vehicle minimize air drag support cargo loads suspend trailer structure transfer loads to road

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

Ford Taurus Integrated Control Panel

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

Steps to Establish the Product Architecture – Ulrich and Eppinger 1.Create a functional model or schematic of the product. 2.Cluster the elements on the schematic. 3.Make Geometric Layouts to achieve the types of product variety. 4.Identify Interactions –Fundamental (must interact) –Incidental

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

Step 2: Cluster Elements into Chunks Reasons to Cluster –close geometric relationship –function sharing –modular –desire to outsource Atmospheric Control Unit Laser Table Powder Engine Control Cabinet

Step 3: Produce Geometric Layout Note: If you can’t make a geometrical layout then go back and redefine chunks and identify interactions

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

Product Architecture Example: Hewlett-Packard DeskJet Printer Part of a portfolio architecture and is composed of parts within a product architecture

DeskJet Printer Schematic Flow of forces or energy Flow of material Flow of signals or data Store Output Store Blank Paper Enclose Printer Provide Structural Support Print Cartridge Position Cartridge In X-Axis Position Paper In Y-Axis Supply DC Power “Pick” Paper Control Printer Command Printer Connect to Host Communicate with Host Display Status Accept User Inputs Functional or Physical Elements

Cluster Elements into Chunks Store Output Store Blank Paper Enclose Printer Provide Structural Support Print Cartridge Position Cartridge In X-Axis Position Paper In Y-Axis Supply DC Power “Pick” Paper Control Printer Command Printer Connect to Host Communicate with Host Display Status Accept User Inputs Paper Tray Print Mechanism Logic Board Chassis Enclosure User Interface Board Host Driver Software Power Cord and “Brick” Functional or Physical Elements Chunks

Geometric Layout

Incidental Interactions Enclosure Paper Tray Chassis Print Mechanism User Interface Board Logic Board Power Cord and “Brick” Host Driver Software Styling Vibration Thermal Distortion RF Interference RF Shielding

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.” Function System Energy Material Informa tion The Wok Example

Generic Dominant Flow Illustration Interface Interaction Material Energy

Dominant Flow Example Fragment of the iced tea brewer FM

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.”

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

Branching Flow Example Fragment of the iced tea brewer FM

Conversion-Transmission Modules Heuristic 3: A conversion sub-function or a conversion-transmission pair or proper chain of sub-functions constitutes a module.

Conversion-Transmission Example Fragment of the iced tea brewer FM

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. Donald V. Steward, Aug. IEEE Trans. on Eng. Mgmt Note: Information flows are easier to capture than work flows. Inputs are easier to capture than outputs.

DSM (Partitioned, or Sequenced) Note: Manipulate the matrix to emphasize features of the process flow. Sequential, parallel and coupled tasks can be identified. Clustering Algorithms

System Team Assignment Based on Product Architecture From “Innovation at the Speed of Information”, S. Eppinger, HBR, January 2001.

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.

Types of Modular Designs Slot Bus Sectional All retain a 1-to-1 mapping of functional to physical elements

Types of Modularity with common interfaces Swapping ModularitySharing Modularity Sectional ModularityBus Modularity Fabricate-to-Fit ModularityMix Modularity Adapted from K. Ulrich,” The Role of Product Architecture in the Manufacturing Firm”, Research Policy, 1995.

Modular vs. Integral ModularIntegral

Example of Modularity K. Ulrich, “The Role of Product Architecture in the Manufacturing Firm” Research Policy, 24, (1995)

Example of Modularity K. Ulrich, “The Role of Product Architecture in the Manufacturing Firm” Research Policy, 24, (1995)

Example of Modularity K. Ulrich, “The Role of Product Architecture in the Manufacturing Firm” Research Policy, 24, (1995)

Sony Walkman

Product Model Lifetime From Sanderson and Uzumeri, The Innovation Imperative, Irwin Survival Time (years) Fraction Surviving Sony AIWA Toshiba Panasonic Sony 1.97 yr Others 1.18 yr Average Life About 200 versions of the Sony Walkman from four platforms!

Platforms and Modularity

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

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

Impact of Modularity Decisions on Later Design Processes

Product Architecture Example: Hewlett-Packard DeskJet Printer

Planning a Modular Product Line: Commonality Table Differentiation versus Commonality Trade off product variety and production complexity

Planning a Modular Product Line: Differentiation Table Differentiation versus Commonality Trade off product variety and production complexity

Supply Chain Issues of Postponing Differentiation

Examples of Postponing Differentiation Paint in Hardware Store Cake in Grocery Store Your experiences….

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

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?

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