Process disturbances and the repair - How do you handle this risk in your company?

Jimmy123

Starting to get Involved
#11
Process disturbance and the repair are to be listed in the P-FMEA
These risks are to effectively handled by way of process validation and machine capability studies.
By a good understanding of the validation, one can know what type of disturbances in process inputs will call for a re-validation of the process.
By a good understanding of the machine, one can know what nature / type of repair will call for performing capability studies again.
How looks like such an example? And what are the preventive and detection actions?
 

somashekar

Staff member
Super Moderator
#12
How looks like such an example? And what are the preventive and detection actions?
Determine when a process needs to be re-validated, including qualification of the change of person managing the process.
Likewise what type of repair needs a capability study.
 

GRP

Involved In Discussions
#13
If we create the P-FMEA the PFC is our input. In our process flow, we donˋt describe process disturbances and the repair. How do you handle this risk in your company? Is there a clear recommendation, how this could be covered, or should this excluded from the risk analysis? Thanks for your replay!
Regarding your original question, I ´ll understand that a machine disturbance is a breakdown.

From my experience a machine breakdown is not part of the process flowchart. I also do not include machine breakdown failure modes in PFMEA. But that has to do with the focus given by my current organization. A machine breakdown is a cause for a failure mode appearing way downstream in shipping.

A requirement in shipping is to ship product type and quantity, on-time, as per client´s PO
The failure mode is product not available/ready
The effects are related to a logistic complaint and its relative severity is factored in the respective table
Cause, e.g. machine breakdown, delayed delivery components, batch segregated due to quality issues,...
Prevention, address each cause individually. For the machine breakdown look at what is -or should be- in place: preventive maintenance plan, spare parts in stock, work instructions for a safe use of equipment, contingency plan, buffer stock (does not prevent the cause, but the failure mode),...
Detection, this will require good judgment in tuning your detection table rankings (the detection of the breakdown may be obvious)

When you mention that repairs can produce new failure modes, you will have to judge if this is really a concern or if you are just trying to make ends meet. If it is the former, you can develop an FMEA for the repair process. If it´s the latter, I would wrap this up in an expedite way in the PFMEA by including a line in the equipment setup verification or production start validation. Whenever a breakdown occurs, or any other anomaly, you call whatever procedure is in place to restart production. This will probably include checking the equipment (e.g. with pass-fail parts) and checking the product (measurements, functional tests, any type of inspection to detect setup issues).

I´d never exclude anything from the risk analysis because it is inconvenient or cumbersome. If the issue is a real concern it has to be raised, if not, then just put it nicely somewhere somehow and tick the box.
 

Jimmy123

Starting to get Involved
#14
Regarding your original question, I ´ll understand that a machine disturbance is a breakdown.

From my experience a machine breakdown is not part of the process flowchart. I also do not include machine breakdown failure modes in PFMEA. But that has to do with the focus given by my current organization. A machine breakdown is a cause for a failure mode appearing way downstream in shipping.

A requirement in shipping is to ship product type and quantity, on-time, as per client´s PO
The failure mode is product not available/ready
The effects are related to a logistic complaint and its relative severity is factored in the respective table
Cause, e.g. machine breakdown, delayed delivery components, batch segregated due to quality issues,...
Prevention, address each cause individually. For the machine breakdown look at what is -or should be- in place: preventive maintenance plan, spare parts in stock, work instructions for a safe use of equipment, contingency plan, buffer stock (does not prevent the cause, but the failure mode),...
Detection, this will require good judgment in tuning your detection table rankings (the detection of the breakdown may be obvious)

When you mention that repairs can produce new failure modes, you will have to judge if this is really a concern or if you are just trying to make ends meet. If it is the former, you can develop an FMEA for the repair process. If it´s the latter, I would wrap this up in an expedite way in the PFMEA by including a line in the equipment setup verification or production start validation. Whenever a breakdown occurs, or any other anomaly, you call whatever procedure is in place to restart production. This will probably include checking the equipment (e.g. with pass-fail parts) and checking the product (measurements, functional tests, any type of inspection to detect setup issues).

I´d never exclude anything from the risk analysis because it is inconvenient or cumbersome. If the issue is a real concern it has to be raised, if not, then just put it nicely somewhere somehow and tick the box.
Thanks, this is exact what we do in past, too. But a lot of failures occur caused after crisis maintenance ( unplaned breakdown) or predictive maintenance. So PM is not really a preventive action, it´s often the cause for failure. How can we Analyse the risk of unplaned operations in FMEA? How do you confirm that the station is in the regular state after maintenance?
 

Jimmy123

Starting to get Involved
#15
Determine when a process needs to be re-validated, including qualification of the change of person managing the process.
Likewise what type of repair needs a capability study.
How can you define a clear process? Each emergency repair is different situation, but always risky.
 

GRP

Involved In Discussions
#16
How do you confirm that the station is in the regular state after maintenance?
Let's say you did a process validation during the project development. How did you establish that "regular state" in the first place? Can't you do that again?

Thanks, this is exact what we do in past, too. But a lot of failures occur caused after crisis maintenance ( unplaned breakdown) or predictive maintenance. So PM is not really a preventive action, it´s often the cause for failure.
How can we Analyse the risk of unplaned operations in FMEA?
The risk that you describe is obviously knowledge gained from experience. So there is no need to wade too much into potential issues, why not just start listing all the failures in a PFMEA sheet and develop the analysis of each failure mode. Like for any pfmea, break the sequence of tasks and create a flowchart. Contextualize with your team how much detail is needed, i.e. you can state something generic like "replace broken part" or you may have to get into each step of replacing the part (remove screws in sequence, remove cover, …)

Doing the analysis will force you to think of causes, preventions and detections.

An output of this fmea could be formalized in a procedure, say "process validation after breakdown". Recommended actions could point to spare parts needed, training required, ...
 

Jimmy123

Starting to get Involved
#17
Let's say you did a process validation during the project development. How did you establish that "regular state" in the first place? Can't you do that again?



The risk that you describe is obviously knowledge gained from experience. So there is no need to wade too much into potential issues, why not just start listing all the failures in a PFMEA sheet and develop the analysis of each failure mode. Like for any pfmea, break the sequence of tasks and create a flowchart. Contextualize with your team how much detail is needed, i.e. you can state something generic like "replace broken part" or you may have to get into each step of replacing the part (remove screws in sequence, remove cover, …)

Doing the analysis will force you to think of causes, preventions and detections.

An output of this fmea could be formalized in a procedure, say "process validation after breakdown". Recommended actions could point to spare parts needed, training required, ...
I am woundering that no such a standard is exists in the industry process validation after breakdown". It seems the maintenance guy dońt use FMEA. Or to many different situations occur what coudńt be analysed. A welding process is totally different to screwing process. If you would analyze the Maintenance plan you will double the process FMEA.
 

somashekar

Staff member
Super Moderator
#18
How can you define a clear process? Each emergency repair is different situation, but always risky.
A optimum process is one that consistently is giving you the desired output.
Agree that each repair is a different situation.
The type of repair that you do can be best decided by you if its risky to your output, As you are the best expert in your situation.
For example., In a machine, the bearing change may be more risky to the machine precision than an electrical fuse replacement.
There are guidance but no standard exists. The guidance tells you to involve subject experts and experiences in deciding your actions.
 

Jimmy123

Starting to get Involved
#19
A optimum process is one that consistently is giving you the desired output.
Agree that each repair is a different situation.
The type of repair that you do can be best decided by you if its risky to your output, As you are the best expert in your situation.
For example., In a machine, the bearing change may be more risky to the machine precision than an electrical fuse replacement.
There are guidance but no standard exists. The guidance tells you to involve subject experts and experiences in deciding your actions.
Is such a guidance from automotive industry available anywhere?
 

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