Use of Recycled Material in Extruded Airbag Gas Generant

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Use of Recycled Material in Extruded Airbag Gas
Generant

• Michael Harte
• 12th Continuous Mixer and Extruder Users Group
  Meeting
• Indian Head , MD
• October 29-31, 2002

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Overview of Airbags

• History and Statistics
• Airbags first installed in the 1970s.
• Over 52 of the current 207 million vehicles on
  the road have driver airbags, 39 have passenger
  airbags.
• All vehicles starting in 1999 are required to
  have both passenger and driver airbags.
• Reduced deployment airbags initiated in model
  year 1998 due to fatalities during deployment.

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Overview of Airbags

• History and Statistics
• Unfortunately, 215 deaths have been attributed to
  
• to airbag deployments.
• Dual stage Driver and Passenger airbags started
  being installed in MY2000 vehicles.
• Smart airbags to be introduced in model year
  2004.
• NHTSA estimates that 9,325 lives have been saved
  by airbag deployments

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Volvo XC90 Autoliv Safety Systems
1. On-Call-SystemThe airbags' electronic control
unit automatically calls a Volvo On-Call
Emergency Center after a severe crash and
provides the rescue team with the location of the
vehicle from the vehicle's GPS navigation system.
This post-crash system can also be used to trace
a stolen vehicle. Introduced in 2000.2. Steering
WheelDriver airbags are increasingly being
delivered integrated with the steering wheels.
Autoliv started with this concept in 1995.3.
Driver AirbagEstimated to reduce driver
fatalities in frontal crashes by approximately
25 (for belted drivers). The vehicle's frontal
airbags have two stages to adjust the deployment
to the crash severity.4. Thorax BagsEstimated
to reduce the risk of serious chest injuries in
side-impact crashes by approximately 20.
Introduced by Autoliv and Volvo in 1994, and now
available in most cars.5. Automatic Height
Adjuster(for the front seat belts) assures that
the shoulder belt is correctly positioned to
provide the best possible restraint
characteristics for different-sized occupants.6.
Seat StructuresProduced by Autoliv since 1996 in
order to develop and promote stronger seat
structures.7. Seat Belt SystemsEstimated to
reduce the risk for serious injuries in frontal
crashes by 40-50. Produced by Autoliv since
1965. The seat belts in the Volvo XC90 havea.)
Pretensioners that tighten the belt at the onset
of a crash, using a small pyrotechnic charge, so
that the restraining of the occupant starts as
early as possible. Introduced by Autoliv in
1989.b) Load Limiters which pay out some seat
belt webbing before the load on the occupant's
chest becomes too high. In the front seats where
there is a risk of hitting the steering wheel or
the dash board, the excessive energy is instead
absorbed more uniformly by the frontal airbags.
The load limiters in the Volvo XC90 are a new
design with two stages to provide an even load on
the occupant's body from the combined seat belt
and airbag system.8. Passenger AirbagEstimated
to reduce fatalities in frontal crashes by
approximately 20 (for belted occupants). Autoliv
has been a pioneer in airbag technologies since
the early 1980's.9. Inflatable Curtain
(IC)Estimated to reduce the risk for
life-threatening head injuries in side-impact
collisions by more than 50. It is also very
efficient for rollover protection. This Autoliv
innovation was introduced in 1998 and will soon
be available in most cars. Manufactured using
Autoliv's patented one-piece weaving
technology.10. Anti-Whiplash Seat
(AWS)Estimated to reduce the risk for neck
injuries in rear-end collisions by more than 50.
an Autoliv innovation introduced in 1998 and
available in all Volvo cars.11. Integrated Child
SeatA foldable seat which makes it possible for
children to use the vehicle's seat belt system,
which is more efficient that a separately
attached belt.12. Belt-In-Seat (BIS)Autoliv has
developed a unique recliner to allow the shoulder
belt to be attached to the backrest of the seat
(instead of the the car structure). BIS will be
especially effective in maintaining clearance
between the head and the roof in rollovers.
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Autoliv Extruded Gas Generant

• Gas Generant Type
• Single perforated grains in the center (0.035,
  0.042, or 0.062)
• Eleven different sizes of O.D. and length
  (ranging from 0.090 x 0.090 to 0.188 x 0.188)
• Three different formulations varying the fuel to
  oxidizer ratio, and also the binder level( guar
  gum)

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Historical Volumes

• Extruders
• Baker Perkins 65-mm (Fall 1997)-L/D25,
  barrel-6 sections,bolted(upper and lower),
  cooling water jackets, 200 lbs/hr.
• Baker Perkins 100-mm (September 1999)-L/D15,
  upper and lower clamshell barrels, cooling water
  jackets, 400 lbs/hr.

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Historical Volumes

• Production Volumes (lbs.)
• CY98 CY99 CY00 CY01
  CY02
• 222,374 772,478 1,308,743 1,272,756
  990,000

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Process Flow
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Historical Volumes

• Scrap Volumes
• CY98 CY99 CY00 CY01 CY02
• 6.8 6.7 3.9 4.5 4.3
• ISO 14001 Team Targets Scrap Reduction and
  Recycle of Material in January, 2000.

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Production Ramp-up
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Team Investigation

• Types of Scrap
• Unacceptable Ballistic Performance
• 19,014 lbs generated in 1998-1999
• Correlating inflator performance to physical
  characteristics of the extrudlets.
• Low Bulk Densities
• 18,580 lbs generated in 1998-1999
• Qualification of the 100-mm extruder in Fall 1999
• Difficulty processing the larger part numbers

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Team Investigation

• Types of Scrap
• Unextrudeable Blends
• 11,152 lbs generated in 1998-1999
• Eliminated this problem by manufacturing HACN
  in-house starting August 1999.
• Bad Assays
• 8,657 lbs generated in 1998-1999
• Operator Training.
• Installation of a Bar Code Reader and DCT
  terminal input of weights.

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Team Investigation

• Types of Scrap
• Out of Specification Lengths
• 1,981 lbs generated in 1998-1999
• Operator learning curve as Part Numbers are
  qualified on
  the 100-mm extruder.
• Total above items is 59,384 lbs

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Post Blend Rework/Recycle

• Customer Approval in February 2000
• Must maintain trace ability
• Only for low performance scrap
• Part number and formulation specific
• 20 lbs per lot, not to exceed 8 by weight

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Team Investigation

• Continuing Problems with Bulk Densities
• Generated 20,614 lbs in 2000
• 1 Scrap generator at 1.6
• Post-blend not allowed for bulk density scrap
• Post-blend rework (20 lbs/lot) does/ will not
  reduce backlog of low performance material.
• Costing _at_2.00/lb for disposal

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Team Investigation

• Sweco Vibratory Grinding Mill
• Safety Testing
• Sizing product powder at 0.065 screen opening
• Qualification at 25,50, and 100 ground
  material.
• Throughput estimated at 120 lbs/hr. Labor
  intensive. Eighty lbs of grinding media per forty
  lbs of extrudlets.
• Offset raw material costs and eliminate disposal
  _at_2.00/lb.

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Safety Data

• Safety Data Testing
• Ground Dust Green line
• Impact gt6.2 9.6 gt4
• Friction gt360 N 240 N gt120 N
• ESD gt11.25 J gt11.25 J gt1 J
• Autoignition 356 0 F 3510 F NA
• Relative ESD Energies
• 0.01 to 0.02 J - Spark off Fingertip
• 0.1 J - Off small piece of charged
  equipment
• 1 to 2 J - Off large piece of equipment

Hygiene PPE same as existing processes
Note Grinding dust can cause skin irritation
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Recycling of Ground Extrudlets

• Customer Approval given in April, 2001
• Maximum 20 by weight per lot
• Maintain original lot trace ability
• Use low Bulk Density, Customer Performance
  Returns, and out of specification Lengths
• Stop using the Post Blend Rework

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Summary

• Recycled Extruded Gas Generant
• The Post Blend Recycle used 46,286 lbs
• The Grinding and Reincorporating has used
  103,573 lbs to date.