Graphical Principles for Rapid Quality Improvement

Forget attributes data. Variables data is where improvement lies.

I’ve spent most of the past two years living in China where I have learned much on how enterprise is managed over there. Many people have said that this century belongs to Asia. That may be, but they have a lot to learn and change before that happens. They cannot depend on cheap rote labor to claim the century.

All of the graphical examples that I present here are based on real data from Chinese companies. The data were stored in a computer or in paper files or were gathered based on my questions. These graphs did not exist before I made them. I have also “sanitized” them to protect the identity of the various companies involved.

Tables of spreadsheet data that look at yesterday’s failures or successes are the norm in China. Defects are recorded and reported using the latest in expensive, automatic equipment for shop floor control systems. One hundred percent final test with reinspection and rework of failed items supposedly guarantee shipped quality. They do not.

…

Want to continue?

By logging in you agree to receive communication from Quality Digest. Privacy Policy.

Create a FREE account

Forgot My Password

Comments

Excellent Article!

It's great to see Bill Scherkenbach writing again! As always, great insight. In a manufacturing environment, many of the things we can track are continuous; wherever possible it will always be better to track the actual measurements.

LED Binning

Regarding LED binning, I have learned the following. Correct me if I'm wrong.
(1) The LED binning is based on the spec of various applications from different customers. With this nature, every bin is possible to be sold if some customer demands. On the other hand, every bin is also possible to be stocked if it meets no spec of any customer. And the price of different bins may not purely be based on the Cpk, or characteristics, of the LED. For example, for white LED, the people in western countries might prefer "coldish" white, while the people in eastern countries might prefer "warmish" white. Therefore, different customers may have different spec for even the same application. For an OEM manufacturer, the customer's requirements and orders are changing rapidly. The bin once "sellable" in plan might become "unsellable" the other day.
(2) The "two groups" phenomenon in fact inherits the characteristics from the incoming material (dice). Unless the LED manufacturers can resolve the supplier quality issue, they just suffer this problem. That said, the characteristics of the dice determines the characteristics mentioned here of the LED.