hi to all
i am having a problem in my company regarding hardness (of rubber, i.e., durometer).
now i studied the things and got to know that there may be 10 causes for the problem.
i found it by using my own methodology.
now how to tackle these problems.
should i use pareto analysis for priorotizing.
and one thing more just tell me in root cause anaysis tools like fish bone etc. can you adress more than 5 causes for the same problem?if yes how?

Ajay,
First, you said you used your own methodology. I am assuming that you mean that you went out and identified the problems yourself. I just want to caution you if this is the case that we all get tunnel vision and we all tempted to see our own pet peeves as the root causes of every situation. This is why it is important if possible to get a team together to identify possible causes.
The cause and effect diagram is a great tool to use to help determine potential causes. The effect is what you are trying to avoid so you put it in as the head. Draw a long horizontal line from the head back. Off of this line there are typically 4-5 main input bones (for example: Man, Machine, Materials, Meathods, Mother nature/environment) Off of each of these bones there can be any number of inputs. Your 10 items would fit off of these main bones (just draw lines off of them). You may even have more items off of them. Add in the rest of the teams thoughts as to cause as well.
After the fish bone is constructed then you chose what is the likely root cause (best to do it with a team unless good data is available). This is where a pareto chart can come in handy if the various items identified are measurable and have data available.

Another method is to ask why did this happen, then of that answer ask why did it happen and to keep doing this until you can not go any further. This will often be the root ( or as close as you can get with your companies knowledge of its system). It is refered to as 5 Whys.

Again, not to be redundant, get a team together if at all possible for root cause. In my opinion, it is the best way to get to the true cause.

Mark

Yes I said that I used my own methodology of why, when, what, where and how but got 10 possible causes from that (team was there). Now I just want to know that how to get on the actual root cause of that problem.
Now Pareto Analysis is done I think to prioritize things like in rejection data (best area I found useful for Pareto Analysis), you are dealing with 5 kinds of rejection like rubber cut, dirty mould, old rubber, mould defect, etc., and you know that out of 100 pieces rejection 50 pieces got rejected due to rubber cut and 20 pieces got rejected due to old rubber. So by Pareto Analysis now I got to know that these are the things which I should focus on (try to remove these problems first by root cause analysis).
But in this present case, I know that I have 10 causes with me but I don't know which is the possible one. The question is how to reach there? In this case, can Pareto Analysis help me?

By definition, a Pareto analysis means that there are multiple root causes. You must identify each root cause and correct that. The Pareto analysis should address the priority of you corrective action, and you may decide not to pursue the "trivial many" for economic reasons.

I recommend a Fault tree analysis. This will help document all of the potential causes on which you choose to focus and each level of the 5-Why for each. You can include the probability of each failure mode as well.

ok i got that
you mean that if a person has some special causes and he knows how much rejection each cause is giving then by pareto analysis we can eradicate the cause which is giving max. rejection.
is it so?a person should know how much effect a certain thing has on process and then priorotise the things acc. to pareto analysis but if one wants to know the cause of a defect then we should use fish bone,why why or a fault tree or some other method.
am i right?

I need to ask a clarifying question: are you saying that you have identified 10 factors that are potential causes to your hardness problem but have no data as to which one is the primary or actual cause of the problem?

If I understand you correctly (and perhaps I don't) then pareto and fishbone and all of that won't help you at this point. you are more in need of experimental techniques to determine with data which of the 10 are creatign the problem.

Which brings up another clarifying question: what is the PROBLEM (effect) in other words what is wrong with the hardness (as quantified by durometer)?

yes you got it right
i have got several causes which may be there effecting the hardness but i dont know the specific cause thats the problem.i am thinking now of making a team and then by studying different causes i think i will get to the main point.
anyways thanks for your help?
just tell me one thing pareto analysis is helpful in situations where u know which cause is having more effect on process and whch one is giving less,if one gets to know that,then he can priorotize certain effects and get to know which one he has to eradicate first?is there any modification you want to make in this statement?
and yes just tell me what are the responsibilities which a quality engineer should be handling in a firm?

You are saying that some causes of rubber hardness defect are (rubber cut, dirty mould, old rubber, mould defect)

please enlighten me on this (im not from rubber industry), these cause dont give much contribution regarding hardness of rubber.

have you considered the Raw Material Quantity , processing lead time. Maybe the person who prepare the material do not follow the correct ratio and quantity of material, or maybe the operator undercooked or overcooked your rubber.

after you determined the correct cause you may use elimination process to determine the real cause.

no no sir these are the defects in rubber industry,this has nothin to do with my problem,i just mentioned these things for example to clarify my points on pareto analysis(when to use it)
i think i am clear now when to use it
thnx for your help sir