What to do if parameters are found to be Outside of Control Limits

[Tmannkzoo]

Hi,

I am looking for a procedure that would clearly define what to do if parameters are found to be out of control limits.

For example if during a baking process the oven were to ramp up above the spec limit for a period of time.


Any input or sample procedures would be of great help!!

 

[Bev D]

I am going to assume that you mean specification limits and not (statistical) control limits. in general, specification limits are intended to distinguish between conditions that will create acceptable product and unacceptable product.

so if the thermal cycle goes beyond the temperature specifications we assume that some adverse consequence has occurred to the parts. we either scrap the parts or rework them - if possible. depending on your industry you may require Customer testing and/or approval prior to rework (or repair).

Of course your specification limits may be simply guidelines or may not have been engineered/validated and so you may have no idea what the adverse consequences may be - if any. this would require expert opinion to assess the potential failures/damage and testing to confirm whether or not the parts were harmed. the result may indicate that the parts be scrapped or reworked or used as is. again you may need customer testing and/or approval - or at least notification - of any rework or use-as-is disposition.

 

[Tmannkzoo]

Thanks for the input and Yes you are correct! Specification limits.

 

[PaulJSmith]

In addition to Bev's excellent advice regarding the product, you'll want to investigate why your process and/or equipment is not adhering to the set limits.

Knowing the effects on the product will help you determine how to handle that. Knowing WHY it happened will help you in preventing its recurrence.

 

[Tmannkzoo]

THANKS! The issue is that I received an observation with correction for this during my recent Audit. The problem being, the process PFMEA is held by the customer. We simply complete a varnish process and bake the parts in a chamber oven that is both validated and calibrated.

My finding reads "are procedures established that would clearly define what to do if parameters are found to be out of control limits"

Since my customer holds the PFMEA I would simply record the findings and return the part to them to make the determination.

I was just curious if anyone may have a similar "generic" procedure that would cover this, with out having to change a current procedure or write up a new one.


Thanks for all your help!!

 

[Bev D]

OK - now I understand your situation. your approach is completely sound

That exact instruction can be documented in a SOP to cover all future occurrences OR you could include a standard 'instruction' on the specific lot work order/traveler or whatever you use to provide specific instructions for each job that has this condition. I've seen both used successfully.