1. INSE 6411 Product Design Theory and Methodology
Product Architecture and Design for X
Lecture 9
Andrea Schiffauerova, PhD.

2. Product architecture
Product architecture is the assignment of the functional elements of a product to the physical building blocks of the product.
The functional elements are the individual operations and transformations (expressed by VERBS)
The physical elements of a product are the parts, components, and subassemblies
The physical elements of a product are typically organized into several major physical building blocks, called chunks.
The purpose of the product architecture is to define the basic chunks in terms of what they do and what their interfaces are

3. Modular product architecture
Each chunk fully embodies one or more product functions.
Interactions between chunks are:
well defined
(typically) fundamental to product‘ primary functions.
Advantages:
simplicity
reusability for a product family or platform.
easier design changes

4. Integral product architecture
Typical functions involve more than one chunk
Typical chunks implement more than one function
Interactions between chunks are ill-defined and may be incidental to product's primary functions.
Advantages:
increased performance
reduced costs for any specific product model.
However:
it may require extensive redesign of the product if a design change is made

5. Modular architecture Example: Trailer
Physical chunks: Product functions:
box
protect cargo
from weather
hitch
connect to vehicle
fairing
minimize air drag
bed
support
cargo loads
springs
suspend trailer structure
wheels
transfer loads to road

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

7. Product architecture
Modular or integral architecture?

8. Modularity - types Modularity is a relative property
Products are rarely strictly modular or integral.
Slot-modular architecture
Each chunk-to-chunk interface is different from the others.
Chunks cannot be swapped around.
Ex.: automobile radio, speedometer
Bus-modular architecture
Uses a common bus, or similar concept.
Uses standard chunk-to-bus interfaces.
Ex.: expansion card for PC
Sectional-modular architecture
No common bus or other single element interfacing with all other chunks.
Uses standard chunk-to-chunk interfaces.
Ex.: sectional sofa, office partitions, piping systems

9. Product architecture selection
Architecture decisions relate to product planning and concept development decisions:
Product change
Product variety
Standardization
Performance
Manufacturing cost
Project management
System engineering

10. Establishing the architecture
Create a schematic illustrating product architecture
Cluster elements
Identify fundamental and incidental interactions

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

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

13. 2. Cluster elements into chunks
Key considerations when clustering elements (of schematic) into chunks include:
Geometric integration and precision
Ex.: H-P clustering for ink-jet printer calls for cartridge positioning on x-axis and paper positioning on y-axis
Function sharing
Ex.: Status display and user controls for H-P printer
Vendor (= Supplier) capabilities
Similarity of design or production technology
Location of change
Accommodating variety
Enabling standardization

14. 3. Incidental interactions
Identification of interactions between chunks:
Fundamental interactions
Planned, well understood interactions
Ex.: H-P printer: Sheets of paper flow from the paper tray to print mechanism.
Incidental interactions
Arise due to the implementation of elements
Ex.: H-P printer: Vibration induced by the actuators in paper tray may interfere with precision positioning of print cartridge (x-axis)

15. 3. Incidental interactions Interaction graph
Enclosure
User Interface
Board
Styling
Thermal Distortion
Paper Tray
Vibration
Print
Mechanism
Logic
Board
Host Driver
Software
RF Interference
Thermal Distortion
RF Shielding
Chassis
Power Cord
and “Brick”

16. Delayed differentiation
Product architecture can be a key determinant of the performance of the supply chain
Delayed differentiation is postponing the differentiation of a product until late in the supply chain
May offer substantial reductions in the costs of operating supply chain, primarily through the reductions in inventory requirements.

17. Figure 9.10

18. Delayed differentiation

19. Design for X
Design for X summarizes a wide collection of specific design guidelines.
X = quality criteria
Design for Manufacturing
Design for Assembly
Design for Reliability
Design for Testing
Design for Maintenance
Design to Cost
Design for Value

20. Design for Manufacturing
Widely used
Poorly defined (the definition may include various practices)
DFM is establishing the shape of components for efficient, high-quality manufacturing
Key concerns:
Specifying the best manufacturing process for each component:
Ensuring that the component form supports the manufacturing process selected
For each manufacturing process there are design guidelines that result in consistent components and little waste

21. Design for Assembly
DFA is the best practice used to measure the ease with which the product can be assembled
DFM focuses on making the components and DFA is concerned with putting them together
DFA measures a product in terms of the efficiency of its overall assembly and the ease with which components can be retrieved, handled and mated.
Retrieval of the components from storage
Handling the components to orient them
Mating the components (bringing them together)

22. Design for Assembly Old seat frame Redesigned seat frame 9 components
20 operations
30 min to assemble
4 components
8 operations
8 min to assemble

23. Design for Assembly Meaningful only for mass produced products!
Expensive tooling is justified only if spread over a large manufacturing volume
In low volume products there is a little payback for changing a design for easier assembly (the cost of assembly is only 1-5% of the total manufacturing cost)
13 DFA guidelines to make products as easy to assemble as possible

24. Nail clipper with one interface
Design for Assembly
Guideline 1: Minimize overall component count
Examine each pair of adjacent components and determine whether they have to be separate (to operate mechanically, different materials, etc.)
Common nail clipper
Nail clipper with one interface
for each function
A one-piece nail clipper

25. A single base for locating
Design for Assembly
Guideline 2: Make minimum use of separate fasteners
Each fastener is one more component to handle
Every fastener adds costs
Fasteners are stress concentrators
Guideline 3: Design the product with a base component for locating other components
A single base on which all other components are assembled
A single base for locating
other components

26. Design for Assembly
Guideline 4: Do not require the base to be repositioned during assembly
Repositioning may be time consuming and costly (especially on larger products)
Guideline 5: Make the assembly sequence efficient
An efficient assembly sequence:
Involves only few steps
Avoids risk of damaging components
Avoids awkward or unstable positions
Avoids creating many disconnected subassemblies

27. Design for Assembly Guideline 6:
Modifications
to avoid tangling
Guideline 6:
Avoid component characteristics that complicate retrieval
Tangling

28. Design for Assembly
Nesting
Modifications to avoid nesting

29. Modification of parts for end-to-end symmetry
Design for Assembly
Guideline 7: Design components for a specific type of retrieval, handling and mating
Manual assembly (less than products annually)
Robot assembly (up to 2 million annually)
Special-purpose machines (more than 2 millions annually)
Modification of parts for end-to-end symmetry
Guideline 8: Design all components for end-to-end symmetry
End-to-end symmetry is a symmetry about an axis perpendicular to the axis of insertion – a component can be inserted in the assembly either end first

30. Design for Assembly
Guideline 9: Design all components for symmetry about their axes of insertion
Strive for axis-of-insertion symmetry (rotational symmetry)
Modification of features for symmetry about the axis of insertion:
Adding a functionally useless notch
Adding a hole and rounding the end

31. Design for Assembly
Modification of a part for symmetry

32. Modification of parts to force asymmetry
Design for Assembly
Modification of parts to force asymmetry
Guideline 10: Design components that are not symmetric about their axes of insertion to be CLEARLY asymmetric
Make components that can be inserted only in the way intended (easy orientation)

33. Design for Assembly
Guideline 11: Design components to mate through straight-line assembly
To minimize the motions of assembly
No reorientation of the base
All the motions are straight down
One-direction assembly

34. Design for Assembly
Use of chamfers (rounded corners) to ease assembly
Guideline 12: Make use of chamfers, leads and compliance to facilitate insertion and alignment
Each component should guide itself into place

35. Design for Assembly Use of leads to ease assembly
Use of compliance to ease assembly

36. Design for Assembly Guideline 13: Maximize component accessibility
Assembly can be difficult if components have no clearance for grasping
Assembly efficiency is low if a component must be inserted in an awkward spot
Modification for tool clearance to ease assembly

37. Design for Reliability
Reliability is a measure of how the quality of a product is maintained over time
Failure is an unsatisfactory performance
Methods:
Failure Mode and Effects Analysis (FMEA)
Helps in identifying the failures, their causes and the corrective actions
Fault Tree Analysis (FTA)
Helps in finding failure modes
Graphically shows all the potential faults and their relationships
Mean Time Between Failures (MTBF)
Average time elapsed between failures

38. Design for Maintenance
Design for Testing
Testability is the ease with which the performance of critical functions is measured
Design for Maintenance
Maintainability or serviceability or reparability describe the ease of diagnosing and repairing the product

39. Design for Environment
Green design or environmentally conscious design or life-cycle design or design for recyclability
After a product’s useful life, the components are disposed (1970s and 1980s), reused or recycled (more and more nowadays)
Why?
Economics
Customer expectation
Government regulations

40. Design to Cost
Design to Cost is a process that constrains design options to a fixed cost limit.
The cost limit is usually what the buyer can pay or what the marketplace demands.
An affordable product is obtained by treating target cost as an independent design parameter that needs to be achieved during the development.

41. Design for Value
Value engineering is a customer-oriented approach to the entire design process
The focus changes from the cost of a component to its value to the customer
Value is function provided per dollar of cost
Compare worth to cost to identify features that have low and high relative values

42. Next lecture Project management Product development economics
Intellectual property rights
Robust design