Jul 16 2019
Updating the 7 tools of QC
A conversation with Franck Vermet about problem-solving tools for factory operators caused me to revisit the 7 tools of QC from 50 years ago and ponder how they should be updated with current data science.
Data Science for Operators, as a book, remains to be written. If you google this phrase today, what comes up is training courses offering to “change your career” by attending a “data science bootcamp.” TIBCO Spotfire has “Workflow Operators” but these are programs, not people.
So the following are tentative answers to questions that haven’t been asked before.
Nov 4 2019
Phase Two Charts and Their Probability Limits | Don Wheeler | Quality Digest
“The ability to react to process changes is more important than protecting yourself from occasional false alarms. […] So do not worry so much about straining out the gnats of false alarms that you end up swallowing the camels of undetected process changes.”
Sourced through Quality Digest
Michel Baudin‘s comments:
The people of the Honda plant in Anna, OH, claim to make the best engines in the world. On the floor, there is neither a single control chart nor any engineer trained in SPC.
Of course, we should fact-check their claim. Rankings of engine quality are not readily googleable. The closest I could find is a ranking of engine reliability from 2014 in a UK blog called The Car Expert, based on data from Warranty Direct, a UK provider of extended warranties. According to them, Honda indeed made the most reliable engines:
According to Anna engineers, their machine tools can hold tolerance ten times tighter than necessary. The few quality problems they do have are due to operators picking the wrong parts in assembly. Control charts in the machine shop would produce nothing but false alarms. With the charts crying wolf, the alarms would lose credibility and nobody would react when a real one hit.
In this kind of situation, Wheeler’s statement can be reversed. The ability to protect yourself against false alarms that send your engineers on wild goose chases is more important than detecting changes that hardly ever happen. You do want to detect changes in the process but control charts are too crude a tool for this purpose.
#SPC, #ControlChart
Share this:
Like this:
By Michel Baudin • Press clippings • 0 • Tags: Control Charts, SPC