Takt Time Concept Still Misunderstood | LinkedIn Discussion

Mark DeLuzio

“What does TAKT Time mean to you and how have you used it to better your business?”



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Michel Baudin‘s comments: It’s 2017, and this question should be unnecessary, but the responses reveal that confusion about this concept is still widespread. As I belong to The Takt Times Group, I felt compelled to participate; at the same time, I didn’t want to repeat everything else I have written on the topic.

About what Takt Time is, there was a litany of the usual oversimplifications about “the heartbeat of the customer,” “the rate of customer demand,” “consumer demand for capacity allocation,” all of which confuse using takt time with making-to-order and forget about the effect of net available work time. Before presenting my own perspective, however, I would like to quote a few posts I agreed with.

Dan Micheau got it right when he wrote:

“Takt time is calculated by available time divided by required output. The units are seconds, minutes or even hours. Anything longer and I’d suggest introducing the concept of “pitch”. If we can set up our system to perform each takt time (stability!) then we can start to improve that system.

Every takt time is a chance to run a scientific experiment to improve. It exposes abnormalities (we welcome them!) and it’s crucial for pacing and synchronizing other parts of our system. I don’t understand how operations can call themselves Lean when people don’t know what the takt time is (or what it means). I always think of takt time as the interval of time that the customer’s giant hand reaches into our factory to grab the next product.”

Mark DeLuzio himself had a good description of the use of takt time in on-going operations that I am used to, with yamazumi charts in assembly or work-combination charts in machine-centered operations:

“You never balance operators to TAKT. You front load all operators and bring them as close to TAKT as possible, and all of the wait time is pushed down to the last operator, who is called the “least man.” So, if TAKT time is 60 seconds and total operator cycle time is 150 seconds, the first two operators are loaded to takt time (60 seconds) and the last operator is only loaded to 30 seconds.

As you continue to do Kaizen and reduce operator cycle time, let’s say by 15 seconds in total from any of the operators , you front load again bringing the first two operators back to takt (60 seconds) and reduce the last operator to 15 seconds. As you continue to Kaizen and reduce operator cycle time, you will eventually be able to eliminate the 3rd operator and run the cell with two people.

However, if you balanced the operators they would all have 50 seconds of load, and you would produce faster than TAKT time therefore overproducing. You also will forever be stuck with three operators.”

And Greg McFalls chimed in:
“We used this same idea in a factory that had over a billion possible variants down one production line. You front load the line. The last operators will be under takt time. Think of takt time as the price is right. You want to be as close as possible without going over. You start with operator 1 and work your way down. Technology goes a long way here and this can be done very quickly by computers. Balancing is a misnomer. You don’t balance the operators to each other – you balance to takt time.” 
My own contributions to the discussion went as follows:
Definition: Assuming we complete the product one unit at a time within the net available work time, the take time is the time that must elapse between two successive unit completions in order to meet the demand. (Lean Assembly, p.43) Sorry to disagree with Shahrukh, but it’s applicable in machining or fabrication as well as assembly.
For details, see:

Takt-driven production is the ideal situation in which each step of the process takes exactly one takt time to complete and transfer to the next step is instantaneous. It only exists in approximations but, if realized, would be free of any of Ohno’s wastes.

To Shahrukh Irani‘s assertion that takt time was only relevant in assembly, I responded that it’s the demand pattern, not the process technology, that determines whether the concept applies. I have been personally involved in cell projects based on takt time in:

  • Making cores in automotive foundries
  • Machining engine blocks in automotive
  • Secondary machining of aircraft components
  • Gear making
  • Machining surgical implants
  • Welding agricultural machinery components
  • Machining surgical implants
  • Welding agricultural machinery components

Usually, takt time is relevant directly to runners, and, with heijunka, to repeaters. It does not apply to strangers. Often the complexities in machine operations are due to mistakes in equipment selection, favoring a small number of monuments over a large number of smaller, less flexible machines that can be dedicated to a runner or a family of repeaters. In a machine shop, this means using a machining center with 60 tool pockets to do repetitive work that you could do more cheaply and with the same quality in a cell of lathes, milling machines, drill presses, etc.

The consideration of takt time should drive both equipment selection and shop floor layout, to avoid all the specific problems you raise. It is of limited use if all you can act on is scheduling. You may nibble percentages in performance, but not achieve orders of magnitude improvements.

Dimensionally, the takt time is not a pace, just like a wavelength is not the same as a frequency. Mathematically, a takt time of 1 minute and a pace of 60 units/hour means the same. Practically, designing a production line to put out one unit every minute gives you a different result from designing it for 60 units/hour. That’s why it matters. When I walk into a plant and ask the plant manager what the takt time is, if he or she says “59 seconds” without hesitation, I have an idea of what to expect on the shop floor. If the answer is “What’s a takt time?” or “We make 61 units/hour,” it gives me a different idea of what to expect inside, like batch processing and WIP floating around.

According to another responder, the idea of takt time as a rate is found in the iSixSigma dictionary, along with the statement that “Takt is the German word for the baton that an orchestra conductor uses.” It is actually “Taktstock.”  I have heard Takt used in German for a bar in sheet music, the time between trains on a line where they run at fixed intervals, and strokes in a car engine. For example, a 4-stroke engine is a “Viertaktmotor.” Unfortunately, nothing named “Six Sigma” is a reliable source on TPS concepts. The difference between a rate and a time is exactly the kind of nuance the Six Sigma community misses.

Also, the net available production time influences the takt time as much as the demand. If you go from 1-shift operation to 2, you double the takt time without any change in the demand. You calculate takt time as a ratio and, in a ratio, the numerator matters as much as the denominator.

The concept of organizing production around a takt time originated in the 1920s in aircraft manufacturing at Junkers in Germany, was taught by German engineers at Mitsubishi Aircraft in Nagoya in 1942, and migrated to Toyota along with aircraft engineers after the war, where it was adapted and refined for car manufacturing. For details, see:

#takttime, #lean, #TPS, #SixSigma