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MPD 575 DESIGN FOR QUALITY. Developed By: Sam Abihana Ion Furtuna Adithya Rajagopal. 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. DEFINITION OF QUALITY.
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MPD 575DESIGN FOR QUALITY Developed By: Sam Abihana Ion Furtuna Adithya Rajagopal
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
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
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
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
PHASES IN UNDERBODY DEVELOPMENT UP V0 (VG-T-80) UP V0 (VG-T-80) UP V0 (VG-T-80) UP V0 (VG-T-80) UP V0 (VG-T-80) UP V1 (VG-T-24) UP V1 (VG-T-24) UP V1 (VG-T-24) UP V1 (VG-T-24) UP V1 (VG-T-24) UP V2 (VG-T-04) UP V2 (VG-T-04) UP V2 (VG-T-04) UP V2 (VG-T-04) UP V2 (VG-T-04) VP Dwg. (VG-E-65) VP Dwg. (VG-E-65) VP Dwg. (VG-E-65) VP Dwg. (VG-E-65) VP Dwg. (VG-E-65) UN V0 UN V1 UN V2 M1DJ PHASES IN UPPERBODY DEVELOPMENT UP V0 UP V1 UP V2 FDJ 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
PRODUCTDESIGN BOUNDARY DIAGRAM INTERFACE MATRIX P-DIAGRAM DFMEA RELIABILITY CHECKLIST ROBUSTNESS DEMONSTRATION MATRIX DVP PROCESS DESIGN PFMEA CONTROL PLAN DFQ PROCESS FLOW
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
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
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
Door Trim Panel Floor Pan Wiring Harness (Vehicle) P.2.1+E P.5+E Seat Cushion Asy P.5+E Cushion Pan Asy P.2.2+E Track Asy P.4+E P.2.1+E Recliners Seat Buckle Asy P.4+E P.8+E P.4+E OCCUPANT P.6+E Seat Back Cushion Asy Back Frame Asy Lumbar Asy P.8 P.5+E Head Restraint Assembly SEAT SYSTEM BOUNDARY DIAGRAM P.2.1+E P.5+E P.8+E
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
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-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
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)
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
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.
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
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
P-Diagram Linkage Boundary Diagram Linkage Interface Matrix Linkage DFMEA: ROBUSTNESS LINKAGES
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SEAT SYSTEM: DFMEA 2 30 SEAT CUSHION Support 200K jounce cycles (90cpm) of 50th percentile male butt form loaded to 200lbs with seat sag <25mm Seat sag >25mm Poor appearance Customer discomfort Inadequate foam density and ILD D: DV Jounce Testing 5 3
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
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 DVM’s
RCL: HOW? Step 1: Choose ideal functions Step 7: List applicable DVM’s Step 8: Use an X to show error states identified by DVM. Identify High Impact DVM’s 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
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
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
FROM RCL RDM: HOW?