A Patently Pernicious Patent
A decade ago Google paid $12.5B for Motorola's Mobility Division, along with 14,600 of Motorola's patents. The patents did not include Six Sigma ... they don't have any! Surprisingly, GE does - "Six sigma design method" ... and it's hilarious.
THE MATRIX
The magic of the patent is to write down "a matrix including CTQs and sigma/confidence factor pairs for each CTQ". Sounds impressive? What's it mean? Well you write down things you are measuring (CTQs) along with their spec limits. Who would have thought of that?
Yikes, sorry, you can't actually do this now. For heaven's sake, it's patented! But wait. The secret sauce is adding Zst to each item on the list. How clever an "invention" is that!
Hang on a minute, what is Zst anyway? Self-confessed con man Harry comes to the rescue. Harry explains that his Zst is "short-term capability". He claims this is equal to "long-term capability" minus his "Z.shift".
Harry's "Z.shift" is his 1.5 sigma shift, based on the height of his stack of discs. Yes, I can see you're having trouble understanding how discs make processes shift but it is what he called the "PILLAR" OF SIX SIGMA. This shift happens to all processes every 50 samples. It's the shift that makes every process in the world wildly out of control. How good is that! No wonder it has been such a big seller.
There is no such thing as a "short-term capability". It is fabricated farce of the fertile mind of a man who said he knew nothing about quality. Harry calls his "short-term capability" an "instantaneous" variation. He claims "long term" is 50 measurements.
In a subsequent and equally contorted "proof" he reduces his "long term" from 50 points to just 6 (ng = 30, n =5 in his subgroup, for g = 6 subgroups). Nuttier than a Macadamia farm.
You now can see why the patent calls it a "matrix" can't you. As the posters say, the "matrix" is "science fiction" and "depicts a dystopian future".
Z SHIFT BAR CHART
Is the "CTQ matrix" all there is that you are not permitted to do because of the patent? There's more! We also have "an exemplary bar chart" showing our Zst vs the number of CTQs. For example, it shows the number of parts with measurements that are "controlled" at 3.4 dpmo. Laughably, it also provides a drawing of a desktop computer on which all this can be magically performed.
The patent gives no description of just how the manufacture of any part has its "Z shift" magically "controlled" at 3.4 dpmo, on the picture of the PC or otherwise.
There is no mention of control charts. As you SHOULD know, any part with a "Z shift" is unpredictable and may produce ANY amount of defects, no matter where specification limits are placed.
SUMMARY
Patents were traditionally intended to protect the inventor from others copying the invention. In the case of GE's Six Sigma patent, it protects users from the disaster of copying the trash. GE needs to be protected from itself.
by Dr Tony Burns BE (Hon 1) PhD (Chem Eng)