Martin Trapp, Ford Motor Company, 5-18-06 1 Squeak and Rattle 101 Martin Trapp Ford Motor Company NVH S&R Department 5-18-06

Martin Trapp, Ford Motor Company, 5-18-06

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Squeak and Rattle 101

Martin Trapp

Ford Motor Company

NVH S&R Department

5-18-06


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Objective : To assure that the vehicle exhibits robust S&R preventative strategies.

The most effective way to cut warranty costs and eliminate squeaks and rattles from a vehicle is to design component, subsystems, and systems that will resist the inputs and excitations of the road and powertrain. These designs need to be incorporated early enough in the vehicle line program in order to be both feasible and cost effective.


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Or the Elimination of Squeak

Squeak, Squeak


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• Rattle: impact contact of adjacent parts i.e., glovebox latch rattles against striker

S&R are subset of all customer Unexpected Noises (UN). These noises are generally random and transient (short time). They can be categorized by physical phenomena

• Buzz: noise radiated from part undergoing resonance vibration i.e., windshield molding buzzes

• Squeak: frictional stick/slip caused by rubbing contact of adjacent parts i.e., door vinyl trim squeaks against to sheet metal


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Causes of Squeak and Itch Shear Movements as Small as 1mm Between Surfaces

Can Generate Noise

Many Parts Can Move 5mm – 10mm (body twist)

Static Coefficient of Friction Creates a Storage/Release of Energy Event (single event, Single Stick Slip, SSS = tick)

Multiple Adjacent Storage/Release Events Cause Unacceptable Noise (multi event, Multiple Stick Slip,

MSS = squeak)


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Examples for Friction Stick-SlipStradivari Middle armrest

Pleasant Stick-Slip Objectionable Stick-Slip


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Methods of Evaluation

• Road Testing (Proving Grounds or End-of-Line) With “Trained” Ears

• 4-Post Test Equipment (Fixed or Portable)

• Component Lab Testing With Controlled Parameters


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Test methods – S&R (Proving Grounds)


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What are we Listening for?

Characteristics:• Amplitude• Frequency• Continuity (continuous or intermittent)• Direction

• Recognition – familiar sound?


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S&R is rarely maskedLow amplitude - rarely masked out - heard through noise from wind, road, engine and exhaust

Music

Audible

Speech

[Hz]

[dB]

S&R

Road


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Squeak and Rattle: Test Track Layout Rationale

• The test tracks are designed to provide the desired input energy (frequency range and amplitude) to excite specific squeak & rattle concerns.– Interior squeaks & rattles– Body creak– Chassis clunk / pop / other noise (suspension noise)– Loose stock

• The surface lengths are optimized to allow sufficient time for the track to excite concerns and for the driver to recognize and locate the source.


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Squeak and Rattle: Generic Best Practice S&R Test Track Layout

Vienna Block

Cobblestone

RaisedVienna Block

Rope

Angle Iron

Washboard

Body Twist Straight

DPG RB / EB

Body Twist on Turn

SpeedTransition

400’

See following slide for details.


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Squeak and Rattle: Generic Best Practice S&R Test Track Layout

Section Concerns Identifiable Driver ActionsDistance

(ft)Speed (mph)

Time (sec) Signs Speed Signs

1. Cobblestone (1) Chassis clunk and pop, loose stock

Maintain steady 5 mph 30 5 4.1 COBBLESTONE Suspension, Frame, Mounts

Speed 5 mph

2. Vienna Block (2) Interior trim S&R Accelerate smoothly to 20 mph 100 5 -> 20 5.7 VIENNA BLOCK Specific by veh: e.g., "Door 12 mph"

Speed 5 -> 20 mph

3. Raised Vienna

Block (2)

Interior trim S&R Maintain steady 20 mph 100 20 3.4 RAISED VIENNA Interior

Speed 20 mph

4. Rough Brick (3) Interior trim S&R (Truck) Maintain steady 20 mph 100 20 3.4 ROUGH BRICK: Interior Speed 20 mph

European Brick (3) Interior trim S&R (Car) EUROPEAN BRICK: Interior

5. Transition Not applicable Decelerate to 5 mph 30 20 -> 5 1.7 DECELERATE Speed 20 -> 5 mph

6. Body Twist on Turn Body creak, chassis clunk and pop

Maintain steady 5 mph 70 5 9.5 TURN & TWIST Body, Frame, Suspension, Mounts

Speed 5 mph

7. Transition Not applicable Straighten vehicle out 20 5 2.7 Speed 5 mph

8. Washboard (4) Specific interior trim S&R frequencies

Accelerate smoothly to 20 mph 100 5 -> 20 5.7 WASHBOARD Specific by veh: e.g. "IP 18 mph"

Speed 5 -> 20 mph

9. Ropes Interior trim S&R noticeable with lighter impact force inputs

Maintain steady 20 mph 100 20 3.4 ROPES Interior

Speed 20 mph

10. Angle Iron Interior trim S&R requiring greater impact force inputs

Maintain steady 20 mph 100 20 3.4 Angle Iron Interior

Speed 20 mph

11. Transition Not applicable Decelerate to 5 mph 30 20 -> 5 1.7 DECELERATE Speed 5 mph

12. Body Twist Body creak, chassis clunk and pop, loose stock

Maintain steady 5 mph 40 5 5.5 BODY TWIST Body, Frame, Suspension, Mounts

Speed 5 mph

13. EXIT EXIT YIELD

Total: 820 ft 50.2 sec


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Squeak and Rattle: Environmental Four Poster


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Squeak and Rattle Component Testing

• Isolate the specific component

• Evaluate under controlled conditions

• Ease of Root Cause Analysis


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Squeak and Rattle Testing


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Squeak and Rattle


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New product content in highly sensitive S&R subsystems (ie. seats, I/P, suspension, body structure, closures hardware).

Models, option content, and body styles offered. Build timing (AA, CP, IB, etc.....) Development milestones (Engineering sign-off, DVP&R

requirements).

Objective : S&R Engineer reviews new product content descriptions and program timing dates to be used in the development of test plans and quality roadmaps.

Look For:

Upfront Design Process


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• IP• Console• Seat• Door System (latches, surfaces,…)

Historic Areas of Concern:

Improved Through:

• Increased Design Clearance• Strengthened Areas• Verification Testing of Alternatives

Subsystems that are not carry over should be checked for rattle. Prioritize based on engineering judgement of rattle risk.


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FRONT DOOR WIRING AND CABLES


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RH SIDE OF IP, BEHIND GLOVE BOX.


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Need flock tape. Interface between center console.


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Foam block needed to be added to 6” behind DVD attachment bracket. Foam block is 60mmx44mm by 50mm


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Door trim bezel switch wire needs to be wrapped in foam sleeve


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Well Protected Wire Harness


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Add Flock tape (or increase retention) to prevent vinyl to sheet metal squeak


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Tools: Material Pair Testing


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Hard Plastic Compatibility Matrix


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End of Presentation


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Enjoy the Conference


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Questions?

“Ask a question and you’re a fool for a minute.Do not ask the question and you're a fool for the rest of your life.” (Chinese proverb)

Documents

Martin Trapp, Ford Motor Company, 5-18-06 1 Squeak and Rattle 101 Martin Trapp Ford Motor Company NVH S&R Department 5-18-06