Hi,
I guess almost of the time, when we are given the task of writing up a corrective action report, be it in any format, we are normally faced with resolving issues that are of "special cause" origin, and generally we can find permanent corrective and preventative actions to put the issue to bed. Normally in most of the cases, a permanent action can be found for special cause. My question is : What happens if the root cause of the problem is found to be due to "common cause", and we have a customer who says problem need to be resolved within seven working days. As you may very well know, Customer is GOD! , no more King nowadays, and he does not care whether u have a common cause or special cause problem.

And you find out that in order to resolve the common cause problem u need to invest in a newer model machine that cost you USD5KK, and on the other hand Management frowns to invest because the volume sold to the customer is to small. But this particular customer buys other products amounting to about 50 percent our total company sales.

You have in the interim period resort to 100 percent screening to weed out the detectives, but neither your company management or the customer is going to accept this screening method long term because of the cost and escapee potential.

How would one go about solving this issue.......

There is no fast solution to a common cause problem.

As you noted, a special cause requires that you restore the process to its original state and put controls in place to keep it in that state.

A common cause requires a process modification. This may mean a number of things ranging from an entirely different method of processing, same method of processing, but different equipment, or same equipment using different process conditions. Any one of these options takes time.

Before you conclude that new equipment is required, have you evaluated the equipment under different operating conditions? Are you trying to reduce variation, or eliminate a defect that is "inherent" in the process?

If you can provide more detail on the process/equipment and the nature of the common cause, we may be able to provide more assistance.

Hi,
Thanks for responding,
The defective rate runs in the region of 8 ppm and it is wafer (semicon) test escapee. Manufacturer has stated that that is the inherent system error of the machine at day one when we bought. He claims no gurantee for less than 50 ppm. But customer is asking for ZD..
What we do is double screening to weed out the defectives.

Hi,
Thanks for responding,
The defective rate runs in the region of 8 ppm and it is wafer (semicon) test escapee. Manufacturer has stated that that is the inherent system error of the machine at day one when we bought. He claims no gurantee for less than 50 ppm. But customer is asking for ZD..
What we do is double screening to weed out the defectives.

Let's assume for the moment that:

The customer's new requirement exceeds the capability of the current process and,
reconfiguring the current process isn't feasible without a price increase and,
the peformance of the current process has been acceptable to the customer in the past.If all of that is true, then the customer is asking to renegotiate terms, and someone has to make a decision as to whether the new terms are acceptable or not. Sometimes it's sufficient to "run the numbers" for the customer and show them that what they're asking for isn't reasonable. You have be very cautious in taking this approach, however, and be very sure that what you're presenting is accurate, and would also reasonably apply to your competitors. Even at that, you might have competitors who are willing to take the hit in order to get the business and get their foot in the door of a new customer, in hopes that their performance with this particular job will lead to more profitable business.

Hi Jim,
Thanks for your response..

I agree with you that i need to churn out accurate and repeatable numbers to convince the customer of the equipment inherent numbers ( quality as produced ). And if that doesnt work, we have to go on doing sort 200% ensure no test escapees reach customer. I do not know of any other options.