Jan 22 2017
Coaching Lean Without Knowing | Bob Emiliani
“I have long felt that people have listened too intently to the analysts who have not actually “played the game” – the interpreters of Toyota’s management system, not the people who actually created it. I think that it is easy for all to agree that someone who actually created something is a much better guide than someone who studied it second-hand.[…] Original sources are the best sources to learn from and should form the fundamental basis of your understanding of TPS and Lean. ”
Sourced through Bob Emiliani
Michel Baudin‘s comments: The originators of Toyota’s production and management system are all dead. This includes Sakichi, Kiichiro and Eiji Toyoda, Taiichi Ohno, Shigeo Shingo, and others, which makes it difficult to learn from them through personal communication. We can read what little they published, or rely on the generations that came after them. The people Emiliani shows to the right of Taiichi Ohno as “originators,” Fujio Cho and Chihiro Nakao, actually are disciples of the originators, which isn’t quite the same. As Emiliani sees it, the alternative to learning from these people is learning from “interpreters” who, as he implies in the title, don’t know what they are talking about because they had no hand in creating it. Are these really the only choices?
“Many topics in lean address how to deal with uncertainty and fluctuations (or mura for unevenness). There is a particularly neat trick for manual lines that self-organizes fluctuations in the workload: the Bucket Brigade! It does have some advantages, but it also has quite a few limitations and prerequisites for it to work. Most importantly it works best only for very short cycle times as for example picking materials. Unfortunately, these requirements are rarely mentioned in literature. Let me show you the basics work in this post before I go into some of the trickier details in the next post.”
Feb 17 2017
Variability, Randomness, And Uncertainty in Operations
This elaborates on the topics of randomness versus uncertainty that I briefly touched on in a prior post. Always skittish about using dreaded words like “probability” or “randomness,” writers on manufacturing or service operations, even Deming, prefer to use “variability” or “variation” for the way both demand and performance change over time, but it doesn’t mean the same thing. For example, a hotel room that goes for $100/night in November through March and $200/night from April to October has a price that is variable but not random. The rates are published, and you know them ahead of time.
By contrast, to a passenger, the airfare from San Francisco to Chicago is not only variable but random. The airlines change tens of thousands of fares every day in ways you discover when you book a flight. Based on having flown this route four times in the past 12 months, however, you expect the fare to be in the range of $400 to $800, with $600 as the most likely. The information you have is not complete enough for you to know what the price will be but it does enable you to have a confidence interval for it.
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By Michel Baudin • Laws of nature 0 • Tags: Deming, Mississippi flood of 1993, Randomness, Toyota, Uncertainty, Variability, Variation