MPD 575 DESIGN FOR QUALITY

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MPD 575 DESIGN FOR QUALITY

• Developed By
• Sam Abihana
• Ion Furtuna
• Adithya Rajagopal

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INTRODUCTION

• Definition of Quality
• What is DFQ
• How DFQ fits into the Ford PD process
• DFQ Process Flow
• Example of DFQ Applied to the Seat System

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DEFINITION OF QUALITY

• The Customer defines Quality Our customers want
  products and services that throughout their lives
  meet their needs and expectations at a cost that
  represents value Ford Quality Policy
• Fitness for use (Fitness is defined by the
  customer) J.M. Juran
• The totality of characteristics of an entity that
  bear on its ability to satisfy stated and implied
  needs ISO 8402
• The loss a product imposes on society after it is
  shipped Taguchi
• A subjective term for which each person has his
  or her own definition American Society for
  Quality

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DESIGN FOR QUALITY (DFQ)

• Quality is intrinsic to a design and is dependent
  on
• Choice of system architecture
• Robustness of execution during the PD process
• Quality is primarily associated with two aspects
  i.e. functional performance and customer
  perception
• DFQ is the disciplined application of engineering
  tools and concepts with the goal of achieving
  robust design development and definition in the
  PD process
• The DFQ process allows the engineer to identify,
  plan-for and manage factors that impact system
  robustness and reliability upfront in the design
  process

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DESIGN FOR QUALITY (DFQ)

• Common product design tools associated with DFQ,
  and discussed in this presentation, are
• Boundary Diagrams
• Interface Matrix
• Parameter Diagram (P-Diagram)
• Design Failure Mode and Effects Analysis (DFMEA)
• Reliability Checklist (RCL)
• Reliability Demonstration Matrix (RDM)
• Design Verification Plan (DVP)
• The engineering concepts associated with the
  tools identified above are based on proven
  methods which can be applied across a variety of
  industries

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DFQ IN THE FORD PD PROCESS (GPDS)

• UN V0/UP V0 Boundary Diagram/Interface
  Analysis/P-Diagram/DFMEA/RDM/RCL initiated.
  Quality History review and documentation
  completed
• UN V1/UP V1 Boundary Diagram/Interface
  Analysis/P-Diagram/DFMEA/RDM/RCL updated
• UN V2/UP V2 Disciplines completed, DFMEA updated
  with recommend actions
• M1DJ Under Body Engineering Freeze/Signoff
• FDJ Upper Body Engineering Freeze/Signoff
  

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DFQ PROCESS FLOW
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BOUNDARY DIAGRAM

• What?
• Defines the scope of the system being studied
• Identifies components that are internal to the
  system
• Identifies system-system, system-human and
  system-environment interfaces (External
  Components)
• Defines the scope of the DFMEA i.e. elements
  within the boundary
• Indicates the nature of all interface
  relationships
• Represents all of the above in a clear graphical
  manner

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BOUNDARY DIAGRAM

• Why?
• Provide a disciplined approach to ensuring all
  system interfaces are considered at design
  initiation
• Understand the nature of interface relationships
  i.e.
• Physically touching (P)
• Energy transfer (E)
• Information transfer (I)
• Material exchange (M)
• Communication tool which facilitates team
  understanding and collaboration

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BOUNDARY DIAGRAM

• How?
• Identify components within the system as blocks
• Establish relationships between the various
  blocks
• Establish relationships between system components
  and other systems, including customer input
• Construct a boundary line around what is best
  included within the analysis of the system
• Boundary diagram analysis should follow system
  hierarchy down to the desired sub-system,
  component level

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(No Transcript)
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SEAT SYSTEM BOUNDARY DIAGRAM
P.2.1E
P.5E
P.8E
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BOUNDARY DIAGRAM LEGEND
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INTERFACE MATRIX

• What?
• Provides a supplemental analysis of the boundary
  diagram
• Quantifies the strength of system interactions
• Provides input to the Potential Effects of
  Failure and Severity column of the DFMEA
• Robustness linkage to the P-Diagram
• Positive interactions may be captured on the
  P-Diagram as input signals or output functions
• Negative interactions may be captured on the
  P-Diagram as input noise or error states
• Why?
• Cross-check boundary diagram interfaces
• Verify positive interactions
• Manage negative interactions for robustness

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INTERFACE MATRIX

• How?
• List all elements within the boundary diagram and
  all elements that interface across the boundary
  in the left most column of the Interface Matrix
  sheet
• Fill the 4 quadrants (Q1-Q4) representing the
  interface relationship (P, E, M, I) between the
  elements of the Boundary Diagram with a rating
  from -2 to 2
• 2 Necessary for function
• 1 Beneficial but not absolutely necessary for
  function
• 0 Does not affect functionality
• -1 Causes negative effects but does not affect
  functionality
• -2 Must be prevented to achieve functionality

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P
E
I
M
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P-DIAGRAM

• What?
• A graphical tool to identify the operating
  environment in robustness focused analysis
• Provides a structured method to identify
• Intended Inputs (Signals)
• Intended Outputs (Ideal Function)
• Unintended Inputs (Noise Factors)
• Unintended Outputs (Error States)
• Design Controllable Factors

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P-DIAGRAM

• What?
• Noise factors are classified as
• Demand related noise which are external to the
  design
• Piece-to-Piece Variation (N1)
• Changes Over Time (N2)
• Capacity related noises which are internal to the
  design
• Customer Usage (N3)
• External Environment (N4)
• System Interactions (N5)

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P-DIAGRAM

• Why?
• Brainstorming tool that supports downstream noise
  factor management strategies (RCL) and
  verification methods (RDM/DV)
• Links to the Function, Potential Failure Mode and
  Potential Effect of Failure columns of the DFMEA

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P-DIAGRAM

• How?
• P-Diagrams should support the scope of the system
  defined in the Boundary Diagram
• Input Output Signals Identified in terms of
  physics as positive interactions in the Interface
  Matrix
• Noise Factors (N1-N5) Error States Identified
  in terms of physics as negative interactions in
  the Interface Matrix. Brainstorming should be
  applied to supplement identification of Noise
  Factors
• Error States Undesired function. Quality History
  should be used to supplement identification of
  error states
• Control Factors List of design factors that can
  be controlled in design i.e. materials,
  dimensions, location etc.

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SEAT SYSTEM P-DIAGRAM
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DFMEA

• What?
• A tool which supports activities that recognize
  and evaluate potential failure modes of a product
  and its effects
• Identifies actions which could reduce or
  eliminate the chances of the failure occurring
• Documents the analysis process

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DFMEA

• Why?
• Improve the quality of product evaluation by
  applying a standardized method
• Determine how failure modes will be avoided in
  design
• Allows the engineer to recognize high
  priority/high impact failure modes and prevent
  them from occurring
• Improve the robustness of the DVP and process
  control plans

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DFMEA ROBUSTNESS LINKAGES
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DFMEA HOW?
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5
7
4
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SEAT SYSTEM DFMEA
SEAT CUSHION Support 200K jounce cycles (90cpm)
of 50th percentile male butt form loaded to
200lbs with seat sag lt25mm
Seat sag gt25mm
Poor appearance Customer discomfort
Inadequate foam density and ILD
D DV Jounce Testing
2
30
5
3
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ROBUSTNESS CHECKLIST (RCL)

• What?
• Captures noise factors and error states
  identified in the P-Diagram
• Identifies areas that require design based noise
  factor management strategies
• Indicates verification methods which provide the
  ability to test for the error states associated
  with the noise factors

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ROBUSTNESS CHECKLIST (RCL)

• Why?
• Initiate team discussion regarding noise factor
  management strategy (NFMS) and robust
  verification
• Focus on noise factors which have the highest
  impact on system robustness
• Understand the correlation between the error
  states and associated noise factors
• Assist robust verification by identifying noise
  factors which are currently not captured by
  existing DVMs

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ROBUSTNESS CHECKLIST (RCL)
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RCL HOW?
Step 1 Choose ideal functions
Step 7 List applicable DVMs
Step 8 Use an X to show error states
identified by DVM. Identify High Impact DVMs
Step 2 Choose focused error states
Step 3 List associated noise factors
Step 4 Define metric and range for each noise
factor
Step 6 Define NFMS
Step 9 Use an X to show noise factors
included in the DVM
Step 5 Assess strength of correlation between
error state and noise factor
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SEAT SYSTEM RCL
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RDM/DVP

• What?
• Planning tool that documents
• Design Verification Methods (DVM)
• Level Tested
• Acceptance Criteria
• Test Timing
• RDM is a subset of the DVP that additionally
  documents
• Failure Mode (Hard or Soft)
• DVM for select tests specified by the RCL
• Noise Factors being tested
• Robustness targets in relation to customer
  expected function. Targets of R/C (R90/C90) are
  not acceptable

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RDM/DVP

• Why?
• Demonstrates that components/systems fulfill
  reliability requirements identified in the RCL
• Provides a forum to review the high impact error
  states and noise factors that affect the system
  along with the identified DVM to prove out their
  system
• Structured documentation of verification test
  plans and timing
• Provides single point summary of test plans

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RDM HOW?
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DVP HOW?