Potential Effects of Failure(s)

kedarg6500

Quite Involved in Discussions
Hi Folks

I am bit confused to write "Potential Effects of Failure".
if I take OD turning operation, Failure mode shall be OD oversize or OD under-size. but when writing Effects of Failure, whether it shall be
1. rejection, rework, sorting OR
2. problem at next operation, problem at customer end

Silly question. isn't it?
 

Marc

Fully vaccinated are you?
Leader
I'm not sure what you mean.

Potential effects of a failure can be catastrophic. It depends upon the end product, it's use, and even in-house failures can be deadly.

I can not remember the specifics, but not so very long ago a small child's toy was found to have lead paint on its exterior.

I once worked in airbag D&D, and I have worked in explosives. In both scenarios an in-house failure could potentially cause death(s), just as an external (customer) failure could cause death. I remember working in explosives the first rule new employees were given is you must always back your car into a parking space so if something went sour (so to speak) there would be minimal confusion in evacuating the area. Not doing so was cause for dismissal.

Your question is not a silly question. Maybe you could give some more context of what you are doing and be a bit more specific.
 

yodon

Leader
Super Moderator
Certainly agree with Marc in that it's not a silly question!

Here, I believe, the concept of detectability can play an important role.

Assume that if your operation makes a part that's too big and it's put into the system as is (too large), the system may jam or fail to operate. If this is a part, say, for an infusion pump, the potential effects could be rather severe! However, if the output is 100% verified (all non-conforming parts are detected) then the likelihood that a system is built with a bad part is virtually eliminated. You may not need to implement any additional (possibly quite costly) controls to control the parts better (at which point it comes down to business decisions).

I think it's important to have some understanding of the downstream impact so you can focus efforts where needed. For example, if that same non-conforming part would have no bearing on form/fit/functionality then you don't want to spend a lot of time on the controls (or level of downstream verification).
 

Miner

Forum Moderator
Leader
Admin
You should evaluate the effect of the failure at multiple levels.

  • What is the effect on the next/subsequent manufacturing operations?
  • What is the effect on the sub-assembly/assembly/product?
  • What is the effect on the system this product goes into?
  • What is the effect on the customer/end user?
 

rob73

looking for answers
This should be limited by the scope of your FMEA, if you are manufacturing an end product then you can identify what affect it will have later on in life, i.e nipple in fuel line too small, fuel leak, explosion. If however you are supplying in a sub-contractor role, you will be limited by your customer specification, unless they are willing to involve you in the wider FMEA.
 

RoxaneB

Change Agent and Data Storyteller
Super Moderator
Hi Folks

I am bit confused to write "Potential Effects of Failure".
if I take OD turning operation, Failure mode shall be OD oversize or OD under-size. but when writing Effects of Failure, whether it shall be
1. rejection, rework, sorting OR
2. problem at next operation, problem at customer end

Silly question. isn't it?

Why must you chose between effect #1 or effect #2? There could be more than one effect...especially if it is not detected immediately. If it is detected immediately, effect #1 is the result. If it is not detected immediately, effect #2 is the result...and then what happens?

Your 'OR' should be an 'AND', in my opinion.
 

Golfman25

Trusted Information Resource
Hi Folks

I am bit confused to write "Potential Effects of Failure".
if I take OD turning operation, Failure mode shall be OD oversize or OD under-size. but when writing Effects of Failure, whether it shall be
1. rejection, rework, sorting OR
2. problem at next operation, problem at customer end

Silly question. isn't it?

First, I agree with what Rob said. If you're a subcontractor all you can really do is look at the failure effect on the next step of your process.

In your case, if the OD is undersized, you likely made scape. Oversized can be re-worked. Then you also look at the effect on the next part of the assembly. Usually it will be some sort of assembly issue. Good luck.
 

kedarg6500

Quite Involved in Discussions
if OD oversize or OD under-size is not detected internally or at customer end, and the part goes to customer assembly line, then how we can describe what shall be problem at customer end?
 

Golfman25

Trusted Information Resource
if OD oversize or OD under-size is not detected internally or at customer end, and the part goes to customer assembly line, then how we can describe what shall be problem at customer end?

You really can't without customer input. The best you can assume is that an out of spec part either will not fit (assembly problem) or not perform properly (hard to know what the particular performance issue will be).
 

SQ_Joe

Involved In Discussions
"The best you can assume is that an out of spec part either will not fit (assembly problem) or not perform properly (hard to know what the particular performance issue will be)."

You will find out very quickly what the particular performance issue is when the Customer sends you their C.A.R.

A PFMEA, which is the subject of this thread, should anticipate every method of creating an out of spec. O.D., or provide a current detection control of the failure mode for the dimension which you are turning. If there is no current detection control method, then Detection will have a ranking of a 10. A 10 is required with no current detection control.

Note(1): The Current Detection ranking of the Failure Mode or Failure Cause must be low enough to meet the Detection ranking require for the S x O, criticallity, risk matrix.

Note(2): It is best to use the Form G template when performing a PFMEA.
 
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