On the Hunt for Bottlenecks

Friday, March 12th, 2010

Lean manufacturing, Bill Waddell says, is the application of the old scientific management concept to the entire factory — not just the direct labor slice:

While any number of authors and ‘experts’ with little actual factory experience point out that the original Ford plant had a Time Study Department and Shigeo Shingo did not consider himself fully dressed in the morning if he did not have his stop watch, there was a huge difference. They were not timing isolated operations looking for direct labor cost savings. They were on the hunt for bottlenecks, looking for anything restricting flow. The only time that matters in a one piece flow plant is the longest time in the flow. Reducing any other time saves nothing. (I imagine Eli Goldratt used a stopwatch when he made his much publicized breakthrough in the chicken coop business. As Goldratt quite accurately points out: An improvement at the bottleneck is an improvement in the system; while an improvement anywhere else is a mirage.) Just because these fellows were carrying stopwatches does not mean they saw factories remotely like Taylor did.

Lean practitioners go from one end of the process to the other looking at every action and every cost, looking to optimize the total. The traditional approach puts direct labor and machine operations on a pedestal. Every other activity is first and foremost supposed to optimize direct labor performance to the old Taylor standard. Only after that goal is met should management then pursue the second goal of minimizing the support cost. One can almost envision the operatic soloist alone in the spotlight while the other performers and the orchestra are hidden in the shadows all doing whatever they have to in order to make the soloist look good. In the remaining traditionally managed American factories, it is the machine operator, surrounded by inventory and a gang of material handlers, inspectors and foremen all assigned the task of making sure that, come what may, that operator makes or exceeds the rate for the job. Lean looks at that and says, “Nonsense”.

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