Need some Help on 8D fault tree analysis
- Thread starter Desouky_emad
- Start date
Welcome to the Cove. You need to provide the details of your question(s) in advance. Also, 8D and Fault Tree Analysis are different but related things.
Have you a cross functional team ready to bring their different perspectives*?
Do they have a clear idea of the problem to be solved?
*and to own the solution (removal of the root causes)?
Do they have a clear idea of the problem to be solved?
*and to own the solution (removal of the root causes)?
As Jim stated, 8D and fault trees are different.
An 8D looks for 3 specific root causes: 1) the specific cause of the defect; 2) the specific reason it escaped detection and got to the customer, and; 3) what specifically went wrong with the QMS that allowed 1 & 2 to occur. However, the causal chain is usually considered to be a serial causal chain with single root causes for each.
A fault tree analysis does not assume a serial causal chain. It assumes that there will be multiple potential causes that will create many branches. The potential causal may have an OR relationship where one or the other make cause the defect by themselves. The potential causal may have an AND relationship where the two (or more) must act together to cause the defect (think of the fire triangle where you must have fuel, oxygen and heat to cause a fire).
Example:
An 8D looks for 3 specific root causes: 1) the specific cause of the defect; 2) the specific reason it escaped detection and got to the customer, and; 3) what specifically went wrong with the QMS that allowed 1 & 2 to occur. However, the causal chain is usually considered to be a serial causal chain with single root causes for each.
A fault tree analysis does not assume a serial causal chain. It assumes that there will be multiple potential causes that will create many branches. The potential causal may have an OR relationship where one or the other make cause the defect by themselves. The potential causal may have an AND relationship where the two (or more) must act together to cause the defect (think of the fire triangle where you must have fuel, oxygen and heat to cause a fire).
Example:
Desouky_emad
Registered
This finding was not about the quality of the PFMEA. It was about the lack of follow through on the recommended actions. Don't put effort into the wrong thing. Just do a 5 Why on why these Recommended Actions were not implemented, why it was not detected and what failed in the QMS. A fault tree or a full-blown 8D is overkill on this.
Desouky_emad
Registered
Thank you for the advice sadly this what I have to follow for the company system
