Too many faulty batches
Statement 5:
Too many batches in production need rework or repair
This is of course not good. 47% of the participants agreed with this statement. There is also a relation with rejects found during production without known root-causes. See <ST04 Failures in production>
All of this has to do with spread in parameters at various places
- design parameters
- manufactory variances
- suppliers
During development one must take care of tolerances in the properties of the used components. Forty years ago is was a tedious job and limited to worst case and best case calculations for as far as possible. Nowadays computer simulation programs can take care of it. But is a not a common task. Cost price of the software?
Even non specified parameters during production can be of influence. See also <ST03 ISO-6 sigma, black belt>
The same is valid for all suppliers and their suppliers and so on. See <ST09 Reliability of suppliers>
If rework or repair happens too often then it might influence the reliability as well. At least it means an uncontrolled process somewhere in the supply chain. Remember that we are a big company from start to fimish. In any case we need to have a serious talk to our supplier. Rework or repair is a solution for short term only. Something is wrong and we want to know the root-causes in order to prevent it in future.
Besides the properties of many components change during life. Usually they weaken. Products with deviations not found during production go to the market and are in fact weakened samples and candidates for failures