Poka Yoke and FMEA Detection Ranking

[Carmine]

In general a process control to be defined as a PY should meet some criteria and follow a particular procedure of validation.
When during a FMEA a control is chosen, for example an automatic control, according AIAG stadard 4th ed the detection ranking associate is 3. The ranking is associate only with the type of control.
If the control is also validate as a PY, is there also a variation in the detection ranking?
I have found nothing written about it. But I see that many people give to PY a ranking of 2 or 1 without a particular reason, just as some practical rule.
Do you have Experience with this topic?
Thanks in advance

 

[Stijloor]

A Quick Bump!

Can someone help?

Thank you very much!

 

[deven_17]

In general a process control to be defined as a PY should meet some criteria and follow a particular procedure of validation.
When during a FMEA a control is chosen, for example an automatic control, according AIAG stadard 4th ed the detection ranking associate is 3. The ranking is associate only with the type of control.
If the control is also validate as a PY, is there also a variation in the detection ranking?
I have found nothing written about it. But I see that many people give to PY a ranking of 2 or 1 without a particular reason, just as some practical rule.
Do you have Experience with this topic?
Thanks in advance

Hi Carmine,

FMEA detection Ratings differ for different Pokayoke's. We only give Detection rating = 3, if Part is already made defective & is locked at the same process.
We can only give detection rating =2, if Defective part can not be made at the station.
For ex-
Assume a process of Welding 2 wires. If the wire thickness is different than specs & PY is able to detect & lock it AFTER welding, its detection = 3
So we can't give 2 rating for above case
However, If the PY don't weld it by catching the error (Wire thickness wrong), its rating = 2.
For Rating = 1 , Error (Wire thickness wrong) is not possible as PY in previous processes or by Design. This rating is rare & if given, be ready for an explanation in any audit ! We have faced it with our product (Airbag)

Thanks,
Deven Malhotra

 

[Chennaiite]

It is indeed a highly precarious situation when people just go by names while giving detection rankings. No secret, a poka yoke is not really 'the one', if it does not perform what it is intended to. Not exactly in FMEA, but recently I visited a supplier who was so over confident about their automated controls that they failed to define adequate controls for the masters which validate automation periodically. This is like having a parachute that may not inflate.