Sep 27 2013
How Ford Eliminated Tickets on Flow Lines | Charles Sorensen | Bill Waddell
See on Scoop.it – lean manufacturing
‘…a part such as a piston entered production bearing a ticket which covered every operation. If ten operations were involved, an entry was made on the ticket after each stage before proceeding to the next one. If one piston was lost in the move, all progress stopped until the missing piece could be found and accounted for. The time consumed in each operation was computed in lots of 100 or more, and results were tabulated on a card file which ultimately found its way back to the foreman so that he might check timing at each stage. Not only did the process mean delay from one operation to another, but when a motor assembler couldn’t get pistons, all car production was held up.’ “
It’s a great story. What Hawkins was implementing is now known as a traveller and, while not usually found in auto parts manufacturing, it lives on in other activities, where it is needed. I saw it in operation last week in small and mid-size plants in Germany that produce paints in thousands of shades in batches from 100Kg to 2,000Kg. Each batch has a traveller attached to it as a way to keep track of where it is in its process and which materials or pigments are needed for it.
In semiconductor manufacturing, you also have travellers, albeit electronic, to keep track of where a batch of wafers is in its 500+ operations process that involves multiple visits to the same equipment, and where the state of a wafer is not visually obvious.
The principle is not intrinsically wrong. The mistake Sorensen reports was applying it in the wrong place.
See on www.idatix.com
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:
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
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By Michel Baudin • Blog clippings • 3 • Tags: ABC analysis, Lean, Low-Volume/High-Mix, Pareto, Runner-Repeater-Stranger