PFMEA for rework, disassembly (automotive).

Nitros1

Starting to get Involved
Hi greetings.

I'm currently revising a PFMEA for a manufacturing process consisting of manual assembly, end of line testing, packaging, etc. The document looks ok and encompasses all of these but, the manufacturing process also has a disassembly table where disassemble ,segregation , rework occur to enter a retesting cycle (as applicable). Technically this just like another work station in the manufacturing process, with its corresponding requirements and failure modes, the problem is that defects that can occur on all stations during the whole sequence of the process can pretty much can be made here too, a botched installation job, an incorrect component installed etc. Fortunately this goes to end of line testing again.
So the questions are: Do the section of the PFMEA addressing this station should contain all of these defects all over again given that they are already stated on the stations where they could be generated ( as it should) with its corresponding controls? Doing so will lower the detection values they already have on their corresponding stations. OR should it be left limited to requirements such as " correct disassemble of .." " correct segregation of.." OR maybe should it be linked in someway so it can refer the reader to the station where the failure mode is already considered, and what would this way be?

What do you guys think?
Thanks.
 
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Johnnymo62

Haste Makes Waste
I think you should re-address all of the previous failure modes that may occur during the work at this rework table. Damage or errors may happen.
 

AndrewK

Involved In Discussions
in my opinion if you do rework- you need to focus on correct identification of parts to be reworked and abscence of damages during disassembly- rest is repetition of assembly processes. So requierements are - correct identification of parts being reworked ,segregation, disassembly, then identification of finished parts, and back to serial process( to testing, packaging etc.). also in our company we have rework, and repair processes in PFD's. But they are not part of standard flow, they are putted as specific processes that may be needed occasionally
 

Ron Rompen

Trusted Information Resource
I agree with Andrew in general. The failure mode at the rework/reassembly station is pretty limited - you can incorrectly repair/rework, fail to return to process at correct step, or cause damage during the repair process. The failures inherent in the assembly process (which are duplicated at the rework process) are already captured once.
 

Nitros1

Starting to get Involved
in my opinion if you do rework- you need to focus on correct identification of parts to be reworked and abscence of damages during disassembly- rest is repetition of assembly processes. So requierements are - correct identification of parts being reworked ,segregation, disassembly, then identification of finished parts, and back to serial process( to testing, packaging etc.). also in our company we have rework, and repair processes in PFD's. But they are not part of standard flow, they are putted as specific processes that may be needed occasionally
Hi good morning thanks for your reply Andrew, and in your case how do you manage the severities? for example the damages during disassembly that you mentioned, do you transfer the severity assigned at the assembly process? thanks
 

AndrewK

Involved In Discussions
Hi good morning thanks for your reply Andrew, and in your case how do you manage the severities? for example the damages during disassembly that you mentioned, do you transfer the severity assigned at the assembly process? thanks
severities always linked to effect ,so in case of rework we choose a highest possible severity for effect on that product (if known) some of them being transferred from assembly processes some of them unic for that one specifically. In case of example of damages during assembly and disassembly (if it is not replaced and go to shipping)-in my personal opinion ,severity would be the same, because according rule being taken highest severity of effect.
 

malasuerte

Quite Involved in Discussions
Hi greetings.

I'm currently revising a PFMEA for a manufacturing process consisting of manual assembly, end of line testing, packaging, etc. The document looks ok and encompasses all of these but, the manufacturing process also has a disassembly table where disassemble ,segregation , rework occur to enter a retesting cycle (as applicable). Technically this just like another work station in the manufacturing process, with its corresponding requirements and failure modes, the problem is that defects that can occur on all stations during the whole sequence of the process can pretty much can be made here too, a botched installation job, an incorrect component installed etc. Fortunately this goes to end of line testing again.
So the questions are: Do the section of the PFMEA addressing this station should contain all of these defects all over again given that they are already stated on the stations where they could be generated ( as it should) with its corresponding controls? Doing so will lower the detection values they already have on their corresponding stations. OR should it be left limited to requirements such as " correct disassemble of .." " correct segregation of.." OR maybe should it be linked in someway so it can refer the reader to the station where the failure mode is already considered, and what would this way be?

What do you guys think?
Thanks.

Short answer Yes - you need to capture them all again and any new ones. Also, one that needs to be addressed which I often see missed is How many reworks are allowed. This needs to be part of that risk assessment as well. Some things do not have an infinite rework limit.
 

fatcatnky

Registered
Hi greetings.

I'm currently revising a PFMEA for a manufacturing process consisting of manual assembly, end of line testing, packaging, etc. The document looks ok and encompasses all of these but, the manufacturing process also has a disassembly table where disassemble ,segregation , rework occur to enter a retesting cycle (as applicable). Technically this just like another work station in the manufacturing process, with its corresponding requirements and failure modes, the problem is that defects that can occur on all stations during the whole sequence of the process can pretty much can be made here too, a botched installation job, an incorrect component installed etc. Fortunately this goes to end of line testing again.
So the questions are: Do the section of the PFMEA addressing this station should contain all of these defects all over again given that they are already stated on the stations where they could be generated ( as it should) with its corresponding controls? Doing so will lower the detection values they already have on their corresponding stations. OR should it be left limited to requirements such as " correct disassemble of .." " correct segregation of.." OR maybe should it be linked in someway so it can refer the reader to the station where the failure mode is already considered, and what would this way be?

What do you guys think?
Thanks.
Hey Nitros, I just started at a new facility that sounds similar to what you're doing. Could I get a look at the PFMEA you've developed?
 
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