Sep 26 2020
More about Toyota and SPC
The post on Does Toyota Use SPC? elicited many comments on LinkedIn. Some suggested that it was scoping SPC too narrowly when contrasting it with Toyota’s approach. In fact, SPC as referenced in the post is the body of knowledge described in the American literature on quality and taught in professional courses.
As to why Toyota is not using SPC, the answer is simple: SPC is about process capability and the quality problems Toyota addresses in 2020 are not due to lack of process capability. In industries that lack process capability, modern data science outguns the old SPC toolkit but that is a different discussion. The most vital question raised in the comments was why we have been not learning Toyota’s approach to quality. In the past 30 years, American industry has learned “Lean Six Sigma” instead.
The comments also enriched the public sources of information cited in the post with corroboration by current and former employees of Toyota.
Oct 30 2020
Who Uses Statistical Design Of Experiments In Manufacturing?
Next to SPC, Design of Experiments (DOE) is the most common topic in discussions of Statistical Quality. Outside of niches like semiconductors or pharmaceuticals, however, there is little evidence of use, particularly in production.
At many companies, management pays lip service to DOE and even pays for training in it. You must “Design experiments” if you pursue continuous improvement.
In manufacturing, DOE is intended to help engineers improve processes and design products. It is a rich but stable body of knowledge. The latest major innovation was Taguchi methods 40 years ago. Since then, Statistics has been subsumed under Data Science and new developments have shifted in emphasis from experimentation to Data Mining.
Experimentation in science and engineering predates DOE by centuries. Mastering DOE is a multi-year commitment that few manufacturing professionals have been willing to make. Furthermore, its effective use requires DOE know-how to be combined with domain knowledge.
Six Sigma originally attempted to train cadres of engineers called “Black Belts” in a subset to DOE. They then served as internal consultants to other engineers within electronics manufacturing. Six Sigma, however, soon lost this focus.
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By Michel Baudin • Technology • 20 • Tags: DOE, Experiment, Experimental Design, Fisher, Lean, Statistical Design of Experiments, Taguchi, TPS