Content by Anthony Chirico
Reverse-Engineer Your ExperimentsBe deliberate about the sample size you use
Thu, 12/06/2018 - 12:03
Everybody wants to design and conduct a great experiment! To find enlightenment by the discovery of the big red X and perhaps a few smaller pink x’s along the way. Thoughtful selection of the best experiment factors, the right levels, the most…
d2: More Than Just a Control Chart ConstantWe owe a debt of gratitude to Tippett and other pioneers who put ‘engineering’ into quality engineering.
Wed, 11/07/2018 - 12:03
Perhaps the reader recognizes d2 as slang for “designated driver,” but quality professionals will recognize it as a control chart constant used to estimate short-term variation of a process. The basic formula shown below is widely used in control…
Applying the Procedures of MIL-STD-105 to Imaginary LimitsProcedure doesn’t allow nonconforming units in the sample, has superior detection capabilities
Mon, 10/15/2018 - 12:03
In my first article, the merits and cautions of AS9138 c=0 sampling plans were discussed and a simple formula was provided to determine the required sample size to detect nonconforming units. In the second article, the process control properties of…
Using MIL-STD-105 As a Process Control ProcedureIn the politically correct world of PPM defective, MIL-STD-105 is a misunderstood and misapplied specification
Mon, 10/08/2018 - 12:02
In my previous article, I discussed the merits and cautions of the “acceptance number” equal zero (c=0) sampling plans contained within AS9138. A simple formula was provided to determine appropriate sample size, and it was illustrated that twice the…
The Paradox of Acceptance SamplingWe keep trying to find the needle in a haystack
Tue, 10/02/2018 - 12:03
Aerospace standard AS9138—“Quality management systems statistical product acceptance requirements” was issued this year (2018), a few years after its accompanying guidance materials in section 3.7 of the International Aerospace Quality Group’s (IAQG…