Finding the Root Cause - Which technique is better?

[Saleha Khalid]

hy sir,
I have a question regarding one of my product's process validation. I am working on prednisolone acetate ophthalmic suspension and 2 of the 10 bulk sample results are out of release limits what could be possible reasons for that.

 

[Bev D]

Well, not to appear unhelpful but your question is unanswerable for us. Simply asking what might cause something - even if we were experts in the product/process - is highly ineffective. There many possible causal mechanisms, starting with incorrect specifications for release to process parameters to raw materials...

This thread is about which problem solving approaches are effective it is not a repository of possible causes.

 

[Evelyn7E]

Hello everyone,

I have a question and needs you to help me.

There are 22 pieces of part rust defects in PDI report last month, I want to establish a projct and organize a team to analysis the root cause with cross function dept. guys, but now I think up two kinds of ways to analysis it, I don't know which ways is better?

The first ways is that I directly input " part rust" into the result column of fish bone diagram, then we use brainstorming to get some possible causes or root causes.

The second ways is that we ask "5 why" to each rust defect to find root cause.

I am a new man for the use of quality tools.

I hope you can give me some good advice.

Thanks & regards!

Terry

Terry, please note that in order to resolve problem you have to first understand the problem, such as What is failure symptom :- what is the pattern of the rust is it in same location or random, is this part made from material that can potentially rust? What is the failure rate now? What was the failure then? How long has the part being in the location. Once problem is well define, then you only start using quality tools to find the potential root cause.

 

[Jim Wynne]

Terry, please note that in order to resolve problem you have to first understand the problem, such as What is failure symptom :- what is the pattern of the rust is it in same location or random, is this part made from material that can potentially rust? What is the failure rate now? What was the failure then? How long has the part being in the location. Once problem is well define, then you only start using quality tools to find the potential root cause.

The things you cite for getting an understanding of the problem are all things that are part of a root cause analysis, not a separate exercise.

 

[Jimmy123]

Not being a fan of fishbone diagrams or root cause brainstorming, I would suggest an alternate approach.

I typically begin with some Problem definition questions (such as those utilized by the Kepner-Tregoe 'Is, Is Not' approach: starting from the very good point that the actual root cause of rust is a well known reaction, I might ask if the parts have some type of rust proofing that has been compromised. Does the customer require that these parts not exhibit rust by contract/drawing requriement? Is this a chronic problem or are these 22 parts with rust something that hasn't been seen before? Are these 22 parts all from one lot? what is a PDI report? were these defects found internally? or by the customer? how many customers?

asnwers to these questions can help direct us and will begin to provide clues as to the next steps...

CQI-20 from AIAG is a good process for Problem Solving!