TO THE MAGIC KINGDOM OF WORLD CLASS QUALITY
CLASS QUALITY, by Keki R. Bhote, page 53:
the MASTER PROBLEM SOLVER. Shainin a portly man. …….
is truly worth his weight in gold ……. for his tremendous
contribution to SPC and the design of experiments, DOE’s.
of the Shainin techniques is captured in his statement:
TO THE PARTS, THEY’RE SMARTER THAN THE ENGINEERS”
What he means
is, don’t guess, also known as engineering judgement, which
variables are important (and thereby excluding hundreds of others),
run long, expensive, and often non-productive DOE’s. Instead,
use his “listening”
tools to separate THE CRITICAL FEW FROM THE TRIVIAL MANY!
parlance, find the “RED X”;.
solving UNSOLVABLE quality problems are characterized as:
WORLD CLASS QUALITY
- Robust and
simple. Almost embarrassingly so,
Keeping It Statistically Simple. No complex formulas, and
- Simple enough
so that direct labor can use them, and sometimes even
“listening”, or separation, tools are:
THE PARETO PRINCIPLE: i.e. 80% of the undesirable output “Y”
by 20% of the causes, “X1”.
Hence by analyzing
the “Y” defect categories (X’s), clues are obtained
to root cause, i.e. X1, the number 1 Pareto defect, and
DEVIATIONS ADD AS THE SQUARE ROOT OF THE SUM OF THE
1.0 to 0, only changes the hypotenuse to 5.0
- But changing
5.0 to 4.0 changes the hypotenuse to 4.1. A 10X difference!!!
- Hence the
RED “X” impact is magnified like a sore thumb.
3 – MULTI-VARI ANALYSIS:
- Next we plot
'Y' deviations for defect X1 in, positional, cyclical, and time format, known as a multi-vari analysis.
From the plot, shown below, we can get fast clues about the root cause “RED
“X”. Is it a positional, cyclical, or a time-to-time
dependent deviation? For example: