AGENDA Day 1
Introductions
Background information - Robert Hoffmann
Objectives
Introduction to Design FMEA
Understand the system - Diagrams
Functions
P – Diagrams
Design FMEA –Functions, Failure Mode, Effects,
Causes, Controls(for failure modes and causes)
THEME
Day 1
Connector à Design
Terminal and Wire assembly à Design
Wire striped ready à Design
Day 2
Prepare wire à Process
Terminal assembly to wireà Process
Assemble wires to connectorà Process
System Name: Wiring Connector
Understand the system
Diagram or drawing of system
Hierarchy Diagram
Boundary Diagram
Functions
Function Tree
Highest Measurable Function
Functional interface diagrams
System Targets
Transfer function
Ideal Output
Error states
'P' Diagram
System Noises
Range of system noises
Effect of system noise on ideal output
Interface Targets
Sub-system Targets
Hierarchy Diagram System Name: Wiring Connector
Boundary Diagram System Name: Wiring Connector
System Boundary
Functions System Name: Wiring Connector
What does the 'Wiring Connector' do?
Conduct Electricity
Connect Wires
Insulate Terminals
Function Tree System Name: Wiring Connector
Function Measure
1. Conduct Electricity How?
1.1. Connect Wires How?
1.1.1. Restrain Wiring loom Pull off load
1.1.2. Position Terminals (axially) Spacing
1.1.3. Contact Mating Terminal Surface area
1.1.4. Retain Mating Connector Pull apart load
2. Insulate Wires How?
2.1. Insulate Terminals How?
2.1.1. Separate Terminals (with insulating material) Thickness / Area
Resistance
2.1.2. Cover Terminals (with insulating material) Thickness / Area
Resistance
How does the wire with terminal support the
Wiring Connector System Functions?
Function Tree System Name: Wire with Terminal
Function Measure
1. Conduct Electricity How? .
1.1. Connect Wires How? .
1.1.1. Position Terminals (lengthwise) Distance
1.1.2. Crimp Wire (at wire to terminal interface) Profile /
Pull off Force
1.1.3. Squeeze Terminal Interference
(at terminal to terminal interface) / Push in force
2. Insulate Wires How?
2.1.1. Restrain Wire Insulation Sleeve (Crimp Sleeve) Pull off load
How does the Wire Assembly support the Wiring Connector System Functions and the wire with terminal Sub-system Functions?
Function Tree System Name: Wire Assembly
Function Measure
1. Conduct Electrical current How? .
1.1. Allow Wire Crimping How? .
1.1.1. Bare Crimp Surface (ready for crimping) Contact Area
1.1.2. Position Wire End (ready for crimping) Wire Length
2. Insulate Wires How? .
2.1. Cover Wires (with insulating material) Thickness /
Resistance
2.2 Minimise Bare Wire (to allow crimping) Length of Bare Wire
When completing a design FMEA the following secondary functions should be considered.
Has any corporate or regulatory target been set?
Has a program specific target been set?
Has a design feature specifically been created to satisfy the potential secondary function?
Should there be a design feature to satisfy the requirement?
Do not try to make a feature fit these requirements.
POTENTIAL SECONDARY FUNCTIONS
1. Perform Safely
2. Perform transparently (to occupants)
2.1. Perform without physical discomfort
2.2. Drive acceptably
3. Assemble Easily
4. Ease Service ability
5. Prevent Tampering
6. Prevent Unauthorised Access
7. Feel Secure
8. Satisfy occupant ergonomics
9. Ease Recycleability
10. Ease Traceability
11. Achieve Electro-Magnetic Compatibility (EMC)
12. Achieve acceptable craftsmanship standards
13. Achieve acceptable underhood tidiness standards
14. Achieve acceptable NVH standards
14.1. Be free from ‘Squeak and Rattle’
14.2. Achieve acceptable sound quality
15. Achieve acceptable crashworthiness
16. Minimise environmental impact
17. Avoid System interactions
Functional interface diagrams System Name: Wiring Connector (both Parts)
Connection
Current
System Targets System Name: Wiring Connector (both Parts)
System Target
Conduct Electricity ------0 to 5V at xx Amps
Continuously when requested
Max % voltage error = x %
Underbonnet temperature range –400C to +1600C ?
System Requirements to meet target
Connect Wires by
Restraining Wiring loom x N Pull off load
Positioning Terminals (axially) x by y mm Spacing
Contacting Mating Terminal x mm2 Surface area
and x mm Interference
Retaining Mating Connector x N Pull-apart load
System Target
Insulate Wires ------Min xxx W resistance
Continuously
Underbonnet temperature range –400C to +1600C
Humidity range ------
System Requirements to meet target
Insulate Terminals by
Separating Terminals x mm Insulation Thickness over entire area
with xx W Resistance
Covering Terminals x mm Insulation Thickness over entire area
with xx W Resistance
Wiring Connector FMEAFunction:
. Conduct Electricity… / Date: / Error StatesDescription
Low Voltage
High Voltage
Oscillating Voltage
Heat
Input
Description Units
Applied Signal V
/ FunctionDescription: -
Conduct electricity
Transfer Function / Ideal Output
Description Units
Received Signal V
.
Noise Factors / Control Factors
Piece to Piece Variation
Pin to socket interferenceConnector pull apart load
Crimping contact area
Wear Out
Pin to socket wear
Corrosion of wire in terminal
Connector retention feature…wear out
Human influences & Duty cycle
Long journeys heating the…underhood airFiddling with wires
Water and Mud splash routes
External Environment
Humidity of surrounding air
Ambient Air temperature
System Interactions
Engine rock (wire stretch)Fixing to body (Strain on terminals)
AGENDA Day 2
Connections with yesterday
Questions
Review Objectives
Introduction to Process FMEA
Understand the Process - Diagrams
Functions: - Process Step, Purpose, Requirements
Design FMEA –Functions, Failure Mode, Effects,
Causes, Controls (for failure mode and causes)
THEME
Day 1
Connector à Design
Terminal and Wire assembly à Design
Wire stripped ready à Design
Day 2
Prepare wire à Process
Terminal assembly to wireà Process
Assemble wires to connectorà Process
PROCESS FMEA
PROCESS FLOW DIAGRAM
OPERATION: Prepare Wire for Crimping
PROCESS FMEA
PROCESS FLOW DIAGRAM
OPERATION: Crimp Terminals onto wire
PROCESS FMEA
PROCESS FLOW DIAGRAM
OPERATION: Assemble wires to Connector
Functions for Process FMEA
For Process FMEA the Function is to complete the step whilst achieving all the requirements set to achieve the design target.
Step Number Purpose Requirements
1. Cut Wire to length
1.1. Unreel wire from drum To supply wire for loom Wire aligned with jig
Sufficient wire on roll
Wire can be gripped by tooling.
1.2. Place wire in cutting Jig To be aligned for cut Wire square to cutter
No dirt or grease on surface
1.3. Cut wire to length Have length to suit loom Correct Length within tolerance
Square Cut
No damage to sleeve
1.4. Unload wire from tooling To transfer to next op Wire removed from cutting area
No damage to sleeve
2. Strip Wire
2.1. Transfer cut wire to Be ready for stripping Transfer without damage
stripper or contamination
2.2. Locate & hold Ensure wire in correct Wire end in correct location
wire in stripper jig position Wire does not slip if pulled
No damage to sleeve
2.3. Strip Wire bare To allow electrical Correct Length within tolerance
to end of wire conduction to terminal is stripped
when crimped No insulation remains in stripped area
Core wire not damaged
2.4. Rotate to present To allow other end Rotate without damage
other end of wire to be stripped or contamination
2.5. as 2.3.
2.6. Unload wire To allow next op No damage to sleeve
from tooling Core wire not damaged