Quality Control and Improvement, Reliability, Liability

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Quality Control and Improvement, Reliability,
Liability

• P. King/Chapter 13 overview

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Reliability is

• A characteristic that describes how good a device
  is.
• Must be planned for, designed in both in terms of
  the initial product and in maintenance of that
  product.

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Failure is

• The degradation of the performance of a device
  (process) outside of a specified value AND
  non-performance or inability to perform its
  function for a given time period within specified
  conditions.
• Defect imperfection
• Deficiency lack of conformance to specs
• Fault Cause of failure
• Malfunction unsatisfactory performance

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Failure Measures

• Real life failure fact of life, define normal
  operation, anticipate worst, try to design out.
• Failure rate typically failures/unit time
  failures/million hours for devices.

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Unreliability is

• A measure of the potential for failure of a
  device (or process.)
• Leads to high cost, wasted time, inconvenience,
  poor reputation, unsafe operation,
• - 9/9/99 more than 10,000 stepladders recalled
  by Home Depot steps too short, improperly
  attached (RIDGID ladders, Louisville Ladder Co,
  Louisville KY)

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Quality is

• The ability to provide stated needs NOW (and is
  implied during warranty period.)
• Warranty period that period of time that you
  guarantee to refund/replace/fix your product.

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Safety Quality in Health Care

• HHS Secretary Tommy G. Thompson today
  (10/11/2001) announced the release of 50 million
  to fund 94 new research grants, contracts and
  other projects to reduce medical errors and
  improve patient safety.
• This research initiative is part of HHS' broader
  efforts to improve the quality of care in America
  and better assure safety across health care
  settings. 

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Reliability Implies

• MTBF of x years (for example, e-1 fail in 5
  years), proportional to the probability of
  service over a period of time, T.
• performs stated function, without failure
  (even with misuse) in the stated environment, for
  a specified period of time.

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Vanderbilt Reliability Risk Engineering
Management

• NSF IGERT awarded 2001
• 2.7 M over 5 years
• BME/ChE/CE/EECS/MT/Math/ME/Owen
• 2 year support toward PhD
• Sankaran Mahadevan, CE

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Electronic Reliability
Infant Mortality
Wearout
Corrosion, Cracking, Wear, Crazing, Shorts
Failure Rate
lt-Useful Life -gt
Joints, Welds, Contamination, Misuse
--? Design, Preventive Maintenance, Replacement, R
epair
Screening, Design, Burn-in
Time -gt
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Mechanical Reliability
Friction, Fatigue, Erosion, Corrosion, Cracking, L
ack of PM
Failure Rate
Misassembly
PM, Replacement
lt- Useful Life -gt
Time-gt
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Software Reliability
Debug errors, Spec. Errors, Special Cases
Failure Rate
Time -gt
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System Reliability Bathtub Curve
QI PM
QI
Lawsuit
Failure Rate
Lawsuit
Time -gt
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Is this a reliable ventilator?
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Product Liability

• Negligence - legal
• Strict Liability - legal
• Breach of warranty legal
• Defects
• Failure to warn

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Negligence

• You owe a duty of care to another
• The standards for that care have been breached
• As a result a compensable injury results
• There are damages or injury to the plaintiff

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Strict Liability

• The PRODUCT is defective or dangerous.
• Risk is too high (risk/benefit higher than
  competition, etc.)

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Breach of Warranty

• Implied Merchantability (Kings Pacemakers)
• Implied Warranty for particular purpose
  (pacemaker)
• Breach of express warranty (written or oral
  contract cures 100)

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Defect

• Actual defect (sharp edges, )
• Consumer expectations
• Risk/benefit
• State of the art
• Defective warnings
• Inadequate guarding

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Failure to warn!

• You have a duty to warn. If you do not warn that
  coffee is hot, you are likely to get in trouble

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Examples

• Coffee burn
• found with head trapped in side rails
• Stepladder recall
• Fluidized air therapy bed
• X-ray/Cobalt therapy accident
• Morphine infusion 3 hours not 24
• LMA cyanosis (see MAUDE)

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Some final key phrases

• Misuse
• Negligent selection
• Failure to inspect
• Use with knowledge of defect
• Alterations
• Disclosure through MAUDE (FDA)
• Disclosure through CPSC (non-FDA)