FMEA and some questions from a teacher

Hello all,

I’m a teacher at the HORITO in Belgium and I will be trying to explain to my students what FMEA is and where it is and can be used. At the moment I have still some questions about this myself. Is there someone who can help me with the following:
- Does anyone has a clear example of an CONCEPT FMEA? I think I understand the theory about it but that won’t be enough to explain to my students.
- A question about the occurance rating at a DESIGN FMEA: failure mode: component breaks, potential causes: 1) wrong usage by customer, he didn’t know how to use it 2) material thickness was wrong calculated by the design engineer.
Does the OCC-rating at 2) say how often a design engineer calculates something wrong or how often the component breaks due to wrong calculation?
- Is the detection of the effect rated the same as the detection of the cause when they are of the same ‘quality’. Their chance to detect is the same.


Very many thanks
Raf Aernouts

Take a look at:
http://Elsmar.com/ubb/Forum12/HTML/000070.html

and its related topic:

FMEA

They will give you a good overview.

ASD...

[This message has been edited by Al Dyer (edited 07 May 2001).]

[Marc]

Also see: http://Elsmar.com/FMEA/

[MSAFAI]

DEAR RAF PLEASE FIND MY REMARKS BELOW IN CAPITAL:

Originally posted by Raf:
Hello all,

I’m a teacher at the HORITO in Belgium and I will be trying to explain to my students what FMEA is and where it is and can be used. At the moment I have still some questions about this myself. Is there someone who can help me with the following:
- Does anyone has a clear example of an CONCEPT FMEA? I think I understand the theory about it but that won’t be enough to explain to my students.
- A question about the occurance rating at a DESIGN FMEA: failure mode: component breaks, potential causes: 1) wrong usage by customer, he didn’t know how to use it 2) material thickness was wrong calculated by the design engineer.
Does the OCC-rating at 2) say how often a design engineer calculates something wrong or how often the component breaks due to wrong calculation?
- Is the detection of the effect rated the same as the detection of the cause when they are of the same ‘quality’. Their chance to detect is the same.

ACCORDING TO AIAG, THE DETECTION RANKING RELTAES TO THE CONTROLS IN PLACE TO 'DETECT' THE FAILURE MODE OR THE CAUSE. THEREFORE CONTROLS ARE NOT RELATED TO THE EFFECT. DETECTION RANKING SHOWS THE ABILITY OF THE CONTROL TO "DETECT" A FAILURE MODE OR A CAUSE. THEREFORE, TO MY VIEW, THE SAME RANKING SYSTEM CAN BE USED FOR BOTH FAILURE MODE AND CAUSE.

I HOPE THIS HELPS TO CLARIFY A BIT.

REGARDS,
MSAFAI


Very many thanks
Raf Aernouts

[Marc]

-> - Does anyone has a clear example of an CONCEPT FMEA? I
-> think I understand the theory about it but that won't be
-> enough to explain to my students.

An FMEA is just a risk analysis. Whether Process, Design, System, Hazardous Operations or whatever - in this case a Concept - you just state the concept and then start listing possible failure modes. A concept FMEA might include possible design and function failures. It might even include some possible process failures related to issues such as buying the prper equipment, I would guess. If it is early enough and broad enough it may even address possible logistics faliure modes.

-> Does the OCC-rating at 2) say how often a design engineer
-> calculates something wrong or how often the component
-> breaks due to wrong calculation?

When your potential failure mode is component breaks because the material thickness was calculated incorrectly by the design engineer, you are addressing how often a design engineer calculates something wrong - in this case the thickness. I would hope this would be a very low number...

-> - Is the detection of the effect rated the same as the
-> detection of the cause when they are of the same
-> 'quality'.

In this case, it would be the probability of detection of the designer's 'mistake' (if s/he makes one and let's hope this isn't a bridge or a building or something like that).

[This message has been edited by Marc Smith (edited 08 May 2001).]

I´m a engineering student and i´ve any doubt about FMEA.

Please sent me what diferents method are used to priorize failure modes.
Why the R
RPN number is not the besty way for priorize?
Whay this diferent methods are more best than RPN?

Thank very much Pauli Adriano