Some of the standard charts used in manufacturing for decades don’t meet today’s criteria for effective visualization. But using them is now a tradition; they are taught in school and their value is unchallenged, but it is time to challenge it. If we were to see these charts for the first time in 2015, would we consider the information they provide useful, and would we want to use the classical formats? This post suggests answers in the case of the venerable Pareto chart.
“…What I came to call Repetitive and Flexible Supply (RFS) is based on the idea of manufacturing the largest products in the same sequence at the same time every week. To many people, this sounds ridiculous and stupid at first.
My analysis consistently showed that, typically, 6% of a company’s products represent 50% of the volume it produces.
I started to see this happen in every factory, hospital, or office I went to. And that’s when it hit me – why not simply focus on stabilizing the plan for that 6% of the products?…”
Ian Glenday’s idea of RFS is fine, but not quite as original as presented in the article. Making it easy to do what you do the most often is the motivation behind the Product-Quantity (P-Q) analysis I learned in Japan in the 1980s.
To use the terminology introduced in the UK by Lucas Industries about that time, it breaks the product mix into Runners, Repeaters, and Strangers. You make each Runner is an dedicated production line, because it has a volume that justifies it.
Then you group Repeaters in families and make them in flexible lines, and you keep a residual job-shop to make the Strangers — the long tail of your demand — products in large numbers but with low and sporadic demand.
This method is described, as prior work, in Lean Assembly as a foundation for assembly line design, and in Lean Logistics for warehouse/supermarket design and for production scheduling, in particular heijunka.