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

Jimmy123

Posts Moderated
#1
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!
 

CCaantley

Involved In Discussions
#2
From what I understand, the process flow is just to show how the process works step to step. Then, using the process flow you create the PFMEA which expands on each step and covers potential risks. The risks are pulled either from similar processes as a guide, or known issues with the process you're working on. So if step 3 in the PFC is tapping a hole, the PFMEA will cover potential setup issues, over/undersized holes, burrs, etc. Creating the PFMEA is an exercise in imagining all the things that could go wrong.
 

Jimmy123

Posts Moderated
#3
From what I understand, the process flow is just to show how the process works step to step. Then, using the process flow you create the PFMEA which expands on each step and covers potential risks. The risks are pulled either from similar processes as a guide, or known issues with the process you're working on. So if step 3 in the PFC is tapping a hole, the PFMEA will cover potential setup issues, over/undersized holes, burrs, etc. Creating the PFMEA is an exercise in imagining all the things that could go wrong.
And what do you think about the fixing process/ operation in case of a machine disturbance? How do you cover this kind of risk in an FMEA, or should this be excluded?
 

CCaantley

Involved In Discussions
#4
And what do you think about the fixing process/ operation in case of a machine disturbance? How do you cover this kind of risk in an FMEA, or should this be excluded?
We usually do cover machine breakdown in our PFMEA. We try to cover every issue that can affect the process, and machine repair would certainly fall in that category. For our shop, there are few jobs that can't run in multiple presses/CNCs, so the RPN is always low for a breakdown.
 

Jimmy123

Posts Moderated
#5
We usually do cover machine breakdown in our PFMEA. We try to cover every issue that can affect the process, and machine repair would certainly fall in that category. For our shop, there are few jobs that can't run in multiple presses/CNCs, so the RPN is always low for a breakdown.
The question is the deep of the repair? Do yo insert the steps for corrective maintenance, like check for wear, if itˋs to high, change the fixture. Unscrew the fixture and replace with new one. Adjust the fixture, 1st part check, restart. Is this what you do? Because in each of this steps can happen new failure who influence the job for production.
 

CCaantley

Involved In Discussions
#6
The question is the deep of the repair? Do yo insert the steps for corrective maintenance, like check for wear, if itˋs to high, change the fixture. Unscrew the fixture and replace with new one. Adjust the fixture, 1st part check, restart. Is this what you do? Because in each of this steps can happen new failure who influence the job for production.
We try to keep the PFMEA as simple as possible, unless we have a 100% known issue. Once we get running and find a significant repair, it will get it's own step in the PFMEA and CP. We'll also see if the PFC needs to be changed to help prevent that issue. I'm still fairly new at these forms, so I wish I could be of more help.
 

somashekar

Staff member
Super Moderator
#10
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!
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.
 

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