【文章內(nèi)容簡(jiǎn)介】 c u r Potential Cause(s)/ Mechanism(s) Of Failure C l a s s S e v Potential Effect(s) of Failure Potential Failure Mode Item Function Examples of Potential Effects ? Noise ? loss of fluid ? seizure of adjacent surfaces ? loss of function ? no/low output ? loss of system ? Intermittent operations ? rough surface ? unpleasant odor ? poor appearance ? potential safety hazard ? Customer dissatisfied Severity ? Definition: assessment of the seriousness of the effect(s) of the potential failure mode on the next ponent, subsystem, or customer if it occurs ? Severity applies to effects ? For failure modes with multiple effects, rate each effect and select the highest rating as severity for failure mode Severity ? EXAMPLE: ? Cannot see out of front window – severity 9 ? Air conditioner makes cab too cold – severity 5 ? Does not get warm enough – severity 5 ? Takes too long to heat up – severity 4 Detect Prevent R P N D E T O C C S E V Action Taken Action Results Response Target Complete Date Remended Actions R P N D e t e c Current Design Controls O c c u r Potential Cause(s)/ Mechanism(s) Of Failure C l a s s S e v Potential Effect(s) of Failure Potential Failure Mode Item Function Classification ? Classification should be used to define potential critical and significant characteristics ? Critical characteristics (9 or 10 in severity with 2 or more in occurrencesuggested) must have associated remended actions ? Significant characteristics (4 thru 8 in severity with 4 or more in occurrence suggested) should have associated remended actions ? Classification should have defined criteria for application ? EXAMPLE: ? Cannot see out of front window – severity 9 – incorrect vent location – occurrence 2 ? Air conditioner makes cab too cold – severity 5 Incorrect routing of vent hoses (too close to heat source) – occurrence 6 Detect Prevent R P N D E T O C C S E V Action Taken Action Results Response Target Complete Date Remended Actions R P N D e t e c Current Design Controls O c c u r Potential Cause(s)/ Mechanism(s) Of Failure C l a s s S e v Potential Effect(s) of Failure Potential Failure Mode Item Function Potential Cause(s)/Mechanism(s) of failure ? Definition: an indication of a design weakness, the consequence of which is the failure mode ? Every conceivable failure cause or mechanism should be listed ? Each cause or mechanism should be listed as concisely and pletely as possible so efforts can be aimed at pertinent causes Cause(s) of Failure ? EXAMPLE: ? Incorrect location of vents ? Incorrect routing of vent hoses (too close to heat source) ? Inadequate coolant capacity for application Detect Prevent R P N D E T O C C S E V Action Taken Action Results Response Target Complete Date Remended Actions R P N D e t e c Current Design Controls O c c u r Potential Cause(s)/ Mechanism(s) Of Failure C l a s s S e v Potential Effect(s) of Failure Potential Failure Mode Item Function Potential Cause Mechanism ? Tolerance build up ? insufficient material ? insufficient lubrication capacity ? Vibration ? Foreign Material ? Interference ? Incorrect Material thickness specified ? exposed location ? temperature expansion ? inadequate diameter ? Inadequate maintenance instruction ? Overstressing ? Overload ? Imbalance ? Inadequate tolerance ?Yield ?Fatigue ?Material instability ?Creep ?Wear ?Corrosion Occurrence ? Definition: likelihood that a specific cause/mechanism will occur ? Be consistent when assigning occurrence ? Removing or controlling the cause/mechanism though a design change is only way to reduce the occurrence rating Occurrence ? EXAMPLE: ? Incorrect location of vents – occurrence 3 ? Incorrect routing of vent hoses (too close to heat source) – occurrence 6 ? Inadequate coolant capacity for application – occurrence 2 Detect Prevent R P N D E T O C C S E V Action Taken Action Results Response Target Complete Date Remended Actions R P N D e t e c Current Design Controls O c c u r Potential Cause(s)/ Mechanism(s) Of Failure C l a s s S e v Potential Effect(s) of Failure Potential Failure Mode Item Function Current Design Controls ? Definition: activities which will assure the design adequacy for the failure cause/mechanism under consideration ? Confidence Current Design Controls will detect cause and subsequent failure mode prior to production, and/or will prevent the cause from occurring – If there is more than one control, rate each and select the lowest for the detection rating ? Control must be allocated in the plan to be listed, otherwise it’s a remended action ? 3 types of Controls – 1. Prevention from occurring or reduction of rate – 2. Detect cause mechanism and lead to corrective actions – 3. Detect the failure mode, leading to corrective actions Current Design Controls ? EXAMPLE: ? Engineering specifications (P) – preventive control ? Historical data (P) – preventive control ? Functional testing (D) – detective control ? General vehicle durability (D) – detective control Detect Prevent R P N D E T O C C S E V Action Taken Action Results Response Target Complete Date Remended Actions R P N D e t e c Current Design C