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
Sep 28 2013
Does This Man Look Efficient? | Businessweek
See on Scoop.it – lean manufacturing
“…Threading the nut is waste, as are the first five turns of the wrench. Only the last quarter-turn of the nut adds value. The customer doesn’t pay you to turn the nut. The customer pays you to fix the joint. My customer—my editor—only pays me to hand in completed articles. Everything else I do up to that point is waste.
Toyota will scratch at tenths of a second to bring down “takt time,” what it takes to complete a single step in a process…”
The coverage of Lean in the mainstream press often turns into a collection of strange statements of this kind.
What does it mean that only the last quarter turn of the nut adds value? The gas cap on my car is fastened with just a quarter turn, but the nuts that hold the engine together are not. When you tighten a nut, force is applied to the entire length of the thread, which makes running down the nut about as “wasteful” as prepping a surface before painting it.
That Business Week’s editor only pays the author for completed articles does not mean that the work of writing them is waste. Customers, generally, are no authority on the process to make what they buy. If you sell something, it’s your job to figure it out. There is what you need to do, and what you don’t. If you need to do it, it’s not waste; if you don’t, it is.
And Takt time is not what it takes to complete a single step in a process! it is a common misconception but it completely misses the point of producing to takt. For a weekly magazine, the takt time is one week.
See on www.businessweek.com
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By Michel Baudin • Press clippings • 1 • Tags: Lean