Feb 27 2014
A brief rant about the ABC’s | Bill Waddell
See on Scoop.it – lean manufacturing
“Apparently the folks writing about stratifying inventory into A, B and C items and building calculations of such into ERP packages didn’t get the lean memo.
Wikipedia is typical of such thinkers when they describe the ABC thought process as:
- ‘A’ items – 20% of the items accounts for 70% of the annual consumption value of the items.
- ‘B’ items – 30% of the items accounts for 25% of the annual consumption value of the items.
- ‘C’ items – 50% of the items accounts for 5% of the annual consumption value of the items.
The idea of micromanaging some items and slacking off on others based on purchase price is the very same theory they taught me at the University of Cincinnati back in the days when … ”
I agree with Bill that, from the point of view of manufacturing operations, the purchase price of materials is not the most important parameter. because the lack of a nail can prevent the completion of a product as effectively as the lack of a pump costing 1,000 times more.
It doesn’t mean, however, that classifying items to treat them differently is wrong, but it must be done by frequency of use rather than price, and I prefer to call the categories “Runners,” “Repeaters,” and “Strangers” rather than A, B, and C.
As a function of rank, I then look for the percentage of units actually built that can be fully assembled with only the items of this rank and higher. It starts at 0%, and, as long as it stays at 0%, I consider the items to be Runners, essentially items you can’t build any product without. At the other end of the spectrum, I call Strangers all the items without which you can make 95% of the units. And everything in-between is a Repeater.
Then you may decide, for example, to dedicate an easily accessible storage location to each Runner, and make special arrangements with suppliers. For Repeaters, you may use the Kanban system, with smaller dedicated locations. And you don’t keep any stock of Strangers, but order them as needed and store them, if at all, in dynamically allocated slots.
See on www.idatix.com
Mar 1 2014
Meeting in Paris with Pen Pals Philip Marris and Christian Hohmann
Philip Marris and Christian Hohmann have been on-line pen pals of mine for years, but we had never actually met. My visit to Paris this week was the opportunity to fix this and trade manufacturing war stories for four hours while having dinner at the landmark La Coupole restaurant.
Both Philip and Christian
have been consulting as long as I have and are authors of books about Lean in French. Philip is an Englishman who speaks French without even a trace of an accent, and writes in French. He describes his own book, Le Management Par Les Contraintes, as “very boring,” because, unlike Eli Goldratt’s The Goal, it is focussed on technical nitty-gritty rather than entertainment. As I told him, this is my favorite kind.
Christian Hohmann has written the following four books:
He has also posted 50 short videos on Youtube. I first approached Christian 15 years ago, when writing Lean Assembly. I had found a picture of an electronics assembly line that he had posted. I wanted to use it in the book, and it had some features I did not understand. I asked him and he gave both the answer and permission to use the picture. When I thanked him this week, he had forgotten about it.
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By Michel Baudin • Book reviews • 3 • Tags: Books, Christian Hohmann, France, Lean, Philip Marris