Squeak and Rattle 101

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Squeak and Rattle 101

• Martin Trapp
• Ford Motor Company
• NVH SR Department
• 5-18-06

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Objective To assure that the vehicle exhibits
robust SR 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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SR are subset of all customer Unexpected Noises
(UN). These noises are generally random and
transient (short time). They can be categorized
by physical phenomena

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

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

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

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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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(No Transcript)
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Examples for Friction Stick-Slip
Stradivari
Middle armrest
Objectionable Stick-Slip
Pleasant 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 SR (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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SR is rarely masked

• Low amplitude - rarely masked out - heard through
  noise from wind, road, engine and exhaust

dB
Audible
Music
Road
Speech
SR
Hz
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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 SR
Test Track Layout
Cobblestone
Washboard
Body Twist on Turn
Vienna Block
Rope
Speed Transition
Raised Vienna Block
Angle Iron
Body Twist Straight
DPG RB / EB
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See following slide for details.
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Squeak and Rattle Generic Best Practice SR
Test Track Layout
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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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Upfront Design Process
Objective SR Engineer reviews new product
content descriptions and program timing dates to
be used in the development of test plans and
quality roadmaps.
Look For

• New product content in highly sensitive SR
  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,
  DVPR requirements).

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

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

Improved Through

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

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