Is takt time the most misunderstood lean concept?
Is takt time the most misunderstood lean concept? My experiences suggests yes, although this surprises me quite a bit.
It’s not that the misunderstanding is highly significant, or has a dramatic impact on people’s actions. But when we ask the question of a group “what is takt time?”, to group that says they know what it means, I see them get it wrong 90+ percent of the time.
Here’s the answer we get: it’s the pace of your production process.
Wrong!
That’s your cycle time. And your cycle almost never equals your takt time. One of the reasons I believe people confuse it so often is because of the lingo. Do we need to use takt time? Half the people think TAKT is an acronym for something. Most wouldn’t know that it’s actually a German word for beat (as in drum beat), adopted by the Japanese and in term by the lean community. But why don’t we call it what it really is:
Customer Demand Rate
Is that hard to understand it’s meaning? Not really; seems pretty clear. This is an example where compliance to the lingo is superseding usefulness.
But the relationship between customer demand rate and cycle time matters, because it helps us understand the waste and opportunity. Here’s the formula used most often, and shared in Mike Rother and Rick Harris’ Creating Continuous Flow:
takt time = your available work time per shift / customer demand per shift
As much as I respect Mike and Rick, I don’t even think this formula is right. It’s mostly right, but saying “shift” assumes a lot about what you’re looking at. Even LEI’s own Lean Lexicon uses “per day” which is also too specific. To be fair, their book is focused on building manufacturing cells, and so shift might be a good choice. But the first question should be “over what time period are we evaluating our operation against the customer demand rate?”
In a previous Leading Lean column titled Save the Heart of the Idea, I describe the use of takt time to K-Mart. K-Mart isn’t thinking about a shift, they are thinking about a smaller block of time. Consider McDonald’s. They also aren’t worried about a shift. They are worried about smaller blocks of time. The operational processes must adjust sometime on an hourly basis driven by the planned and known changes in the customer demand rate. The takt time is different from 11:30 – 1 than it is from 2-4. This isn’t just variation in demand; it’s specific shifts in demand.
Unless your process is waste free, if your cycle time equals your takt time, you will miss customer orders. Congratulations if you’ve achieved this ideal. But the goal is not to get cycle time to match takt time; the goal is to make sure that a stable process including its waste is meeting customer demand. Then you work towards eliminating that waste. But that’s a useful way to think about takt time. Your cycle time plus your waste must be able to match up. And mathematically, the amount of waste grows as you go back into the process, and so therefore each preceding segment of the process must be running a little faster.
Takt time is a very useful concept. It helps you understand what you are building towards. It helps you align your process towards the needs. When we fail to grasp the purpose of the concept and boil it down to only a formula, or worse, a wrong definition, we lose all of the benefit.
It is issues like this that help demonstrate that lean is not just common sense as many like to claim. On the surface, yes, it just makes sense. But when you get into real application and understanding, there are many nuances which subtle changes in meaning can have a big impact. Lean isn’t easy. If it was, everyone would be successful at it, and it would no longer be a competitive advantage.
Reflection question: How have you used takt time to design, manage, and improve your process? How important is having a common interpretation to your organization?
Would you like to receive these posts in your inbox as they are published? Add your email to the Subscribe box on the right side of the page.
Great post, Jamie! We are in the process of redesigning a production line in a power equipment factory and I’ve been told historically we strive for a 30 min. takt time. Your post leads me to believe I might have to look at it again because it might have been cycle time that was misinterpreted as takt time. Care to take a stab at what that new formula would look like?
Best!
Dave
Great post, Jamie! We are in the process of redesigning a production line in a power equipment factory and I’ve been told historically we strive for a 30 min. takt time. Your post leads me to believe I might have to look at it again because it might have been cycle time that was misinterpreted as takt time. Care to take a stab at what that new formula would look like?
Best!
Dave
Great post, Jamie! We are in the process of redesigning a production line in a power equipment factory and I’ve been told historically we strive for a 30 min. takt time. Your post leads me to believe I might have to look at it again because it might have been cycle time that was misinterpreted as takt time. Care to take a stab at what that new formula would look like?
Best!
Dave
A good friend who guided me into a lot of lean thinking used to say that “Takt is a choice.” By that he meant that takt is more than simply the math of demand over time but that it is the company’s choice of what to establish as demand. His rationale was that demand is constantly changing so do we use the last actual demand? Or do we use some upcoming forecasted demand? Do we factor in seasonality or smooth it out? Over what time period? A different answer for McDonalds than for lawn mowers or power plants.
It seems to me that the time period over which we establish demand and therefore takt should somehow be related to the time period at which we can make changes to our operations in order to respond to changing takt. I be interested ideas on that thought.
Phil
A good friend who guided me into a lot of lean thinking used to say that “Takt is a choice.” By that he meant that takt is more than simply the math of demand over time but that it is the company’s choice of what to establish as demand. His rationale was that demand is constantly changing so do we use the last actual demand? Or do we use some upcoming forecasted demand? Do we factor in seasonality or smooth it out? Over what time period? A different answer for McDonalds than for lawn mowers or power plants.
It seems to me that the time period over which we establish demand and therefore takt should somehow be related to the time period at which we can make changes to our operations in order to respond to changing takt. I be interested ideas on that thought.
Phil
A good friend who guided me into a lot of lean thinking used to say that “Takt is a choice.” By that he meant that takt is more than simply the math of demand over time but that it is the company’s choice of what to establish as demand. His rationale was that demand is constantly changing so do we use the last actual demand? Or do we use some upcoming forecasted demand? Do we factor in seasonality or smooth it out? Over what time period? A different answer for McDonalds than for lawn mowers or power plants.
It seems to me that the time period over which we establish demand and therefore takt should somehow be related to the time period at which we can make changes to our operations in order to respond to changing takt. I be interested ideas on that thought.
Phil
I always liked to guide my team through this concept using a short worksheet:
Takt Time Calculation
Available Time
___ hours / shift mins
-Breaks mins
-Wash Up mins
-Clean Up mins
min./shift
# of Shifts
Total Available Time min./day
Customer Demand units/month
(# units/month) / (22 days/month)
units/day
Takt Time
(min/day)/(units/day)= min./unit
(min./unit) / (60 sec./min.)
Takt Time sec./unit
Notes:
– Takt time is determined by customer demand
– Operator Cycle Time is NOT Takt time, it is a time measure of operator activities
– Machine Cycle Time is NOT Takt time, it is a time measure of machine activities
– Total Cycle Time is NOT Takt time, it is a time measure of total cycle activities
I always liked to guide my team through this concept using a short worksheet:
Takt Time Calculation
Available Time
___ hours / shift mins
-Breaks mins
-Wash Up mins
-Clean Up mins
min./shift
# of Shifts
Total Available Time min./day
Customer Demand units/month
(# units/month) / (22 days/month)
units/day
Takt Time
(min/day)/(units/day)= min./unit
(min./unit) / (60 sec./min.)
Takt Time sec./unit
Notes:
– Takt time is determined by customer demand
– Operator Cycle Time is NOT Takt time, it is a time measure of operator activities
– Machine Cycle Time is NOT Takt time, it is a time measure of machine activities
– Total Cycle Time is NOT Takt time, it is a time measure of total cycle activities
I always liked to guide my team through this concept using a short worksheet:
Takt Time Calculation
Available Time
___ hours / shift mins
-Breaks mins
-Wash Up mins
-Clean Up mins
min./shift
# of Shifts
Total Available Time min./day
Customer Demand units/month
(# units/month) / (22 days/month)
units/day
Takt Time
(min/day)/(units/day)= min./unit
(min./unit) / (60 sec./min.)
Takt Time sec./unit
Notes:
– Takt time is determined by customer demand
– Operator Cycle Time is NOT Takt time, it is a time measure of operator activities
– Machine Cycle Time is NOT Takt time, it is a time measure of machine activities
– Total Cycle Time is NOT Takt time, it is a time measure of total cycle activities
Dave, it’s hard to solve from here. And I don’t think it’s a new formula. The formula is for the most part, sound. It’s the use. And it starts with the time period. The first question I would be asking is, over what time period will we adjust. Sometimes we’re looking at it within hours, sometimes very long. We have a client that builds one unit per year. You first must understand how you want calculating takt time to inform you about how to design your operations.
Phil, I like “takt is a choice.” That’s an excellent way to put it.
Dave, it’s hard to solve from here. And I don’t think it’s a new formula. The formula is for the most part, sound. It’s the use. And it starts with the time period. The first question I would be asking is, over what time period will we adjust. Sometimes we’re looking at it within hours, sometimes very long. We have a client that builds one unit per year. You first must understand how you want calculating takt time to inform you about how to design your operations.
Phil, I like “takt is a choice.” That’s an excellent way to put it.
Dave, it’s hard to solve from here. And I don’t think it’s a new formula. The formula is for the most part, sound. It’s the use. And it starts with the time period. The first question I would be asking is, over what time period will we adjust. Sometimes we’re looking at it within hours, sometimes very long. We have a client that builds one unit per year. You first must understand how you want calculating takt time to inform you about how to design your operations.
Phil, I like “takt is a choice.” That’s an excellent way to put it.
I like to focus on the cultural aspects of process improvement, and there is often little attention paid to the intangible, “soft” side that yields buy-in for change initiatives. Your post, however serves as a great reminder of how using the tools correctly helps reduce the burden on the individual. It speaks directly to the concepts of mura and muri in operations. Clearly, proper use of takt time can even the flow and prevent those periodic crises that wear people out as they contend with the booms and busts that result from poor planning.
I like to focus on the cultural aspects of process improvement, and there is often little attention paid to the intangible, “soft” side that yields buy-in for change initiatives. Your post, however serves as a great reminder of how using the tools correctly helps reduce the burden on the individual. It speaks directly to the concepts of mura and muri in operations. Clearly, proper use of takt time can even the flow and prevent those periodic crises that wear people out as they contend with the booms and busts that result from poor planning.
I like to focus on the cultural aspects of process improvement, and there is often little attention paid to the intangible, “soft” side that yields buy-in for change initiatives. Your post, however serves as a great reminder of how using the tools correctly helps reduce the burden on the individual. It speaks directly to the concepts of mura and muri in operations. Clearly, proper use of takt time can even the flow and prevent those periodic crises that wear people out as they contend with the booms and busts that result from poor planning.
Good post, Jamie. The other thing I see people getting confused about is that takt time is related to the number of workers. They often struggle to understand that demand is demand no matter how many people do the work. Also, if I’m working with a team that has difficulty remembering what goes in the numerator and what goes in the denominator, I do offer takt as a acronym, but only as a mnemonic device – “time available” divided by what “kustomer takes.” Not precise linguistically, but it does the trick.
Another thought your post triggered for me is that I often hear that takt doesn’t apply at all to office /service environments. While it’s tricky to apply it and often requires segmenting the work so that people aren’t switch-tasking as much, it absolutely applies. I’ve used takt time effectively to manage work in high and low demand periods (e.g. a different takt time for end of quarter vs. all other times). Agree?
Finally, good point about the demand timeframe. I’ve calculated takt for for annual, quarterly, monthly, weekly, daily, and hourly demand. Shift is certainly not the only period to consider.
Again, good reminder for a commonly misunderstood subject.
Good post, Jamie. The other thing I see people getting confused about is that takt time is related to the number of workers. They often struggle to understand that demand is demand no matter how many people do the work. Also, if I’m working with a team that has difficulty remembering what goes in the numerator and what goes in the denominator, I do offer takt as a acronym, but only as a mnemonic device – “time available” divided by what “kustomer takes.” Not precise linguistically, but it does the trick.
Another thought your post triggered for me is that I often hear that takt doesn’t apply at all to office /service environments. While it’s tricky to apply it and often requires segmenting the work so that people aren’t switch-tasking as much, it absolutely applies. I’ve used takt time effectively to manage work in high and low demand periods (e.g. a different takt time for end of quarter vs. all other times). Agree?
Finally, good point about the demand timeframe. I’ve calculated takt for for annual, quarterly, monthly, weekly, daily, and hourly demand. Shift is certainly not the only period to consider.
Again, good reminder for a commonly misunderstood subject.
Good post, Jamie. The other thing I see people getting confused about is that takt time is related to the number of workers. They often struggle to understand that demand is demand no matter how many people do the work. Also, if I’m working with a team that has difficulty remembering what goes in the numerator and what goes in the denominator, I do offer takt as a acronym, but only as a mnemonic device – “time available” divided by what “kustomer takes.” Not precise linguistically, but it does the trick.
Another thought your post triggered for me is that I often hear that takt doesn’t apply at all to office /service environments. While it’s tricky to apply it and often requires segmenting the work so that people aren’t switch-tasking as much, it absolutely applies. I’ve used takt time effectively to manage work in high and low demand periods (e.g. a different takt time for end of quarter vs. all other times). Agree?
Finally, good point about the demand timeframe. I’ve calculated takt for for annual, quarterly, monthly, weekly, daily, and hourly demand. Shift is certainly not the only period to consider.
Again, good reminder for a commonly misunderstood subject.
Thanks for this post Jamie,
Some remarks based upon my exprience using takt.
The concept of calculating a takt for a period also relates to the various planning horizons and thus the possibilities (flexibility) an organization has reacting to takt time shifts. Big takt time shifts from period to period can sometimes not be accomodated (using current capability in volume flexibility and using multi-skilling) and therefore need to be leveled over a longer planning period. This leveling may reduce swings in required capacity but will of increase the required buffering in other ways (inventory buildup and depletion).
We used this concept in regulating kanbans that came back from shipping and fed into our heijunka board: do you replenish all, or level over a longer period than the frequency with which you get back your kanbans? We always had many discussions on this. These discussions also considered another basic aspect of Lean, namely to put enough tension (not stress) onto the system so that it trggers improvement. When leveling over a longer period, we provide relief to the system compared to the market, when we shorten the period, we more and more have to able to react to short term market shifts. So… you try and pick the period and then continuously improve 😉
Best regards,
Rob van Stekelenborg, Dumontis
Thanks for this post Jamie,
Some remarks based upon my exprience using takt.
The concept of calculating a takt for a period also relates to the various planning horizons and thus the possibilities (flexibility) an organization has reacting to takt time shifts. Big takt time shifts from period to period can sometimes not be accomodated (using current capability in volume flexibility and using multi-skilling) and therefore need to be leveled over a longer planning period. This leveling may reduce swings in required capacity but will of increase the required buffering in other ways (inventory buildup and depletion).
We used this concept in regulating kanbans that came back from shipping and fed into our heijunka board: do you replenish all, or level over a longer period than the frequency with which you get back your kanbans? We always had many discussions on this. These discussions also considered another basic aspect of Lean, namely to put enough tension (not stress) onto the system so that it trggers improvement. When leveling over a longer period, we provide relief to the system compared to the market, when we shorten the period, we more and more have to able to react to short term market shifts. So… you try and pick the period and then continuously improve 😉
Best regards,
Rob van Stekelenborg, Dumontis
Thanks for this post Jamie,
Some remarks based upon my exprience using takt.
The concept of calculating a takt for a period also relates to the various planning horizons and thus the possibilities (flexibility) an organization has reacting to takt time shifts. Big takt time shifts from period to period can sometimes not be accomodated (using current capability in volume flexibility and using multi-skilling) and therefore need to be leveled over a longer planning period. This leveling may reduce swings in required capacity but will of increase the required buffering in other ways (inventory buildup and depletion).
We used this concept in regulating kanbans that came back from shipping and fed into our heijunka board: do you replenish all, or level over a longer period than the frequency with which you get back your kanbans? We always had many discussions on this. These discussions also considered another basic aspect of Lean, namely to put enough tension (not stress) onto the system so that it trggers improvement. When leveling over a longer period, we provide relief to the system compared to the market, when we shorten the period, we more and more have to able to react to short term market shifts. So… you try and pick the period and then continuously improve 😉
Best regards,
Rob van Stekelenborg, Dumontis
Hi Jamie
Good reflection. I would take it a step further and simply define takt time as “the beat”. As you pointed out the time window and customer demand will vary greatly depending on whether the process is repetitive manufacturing, retail, healthcare or education. The idea is to synchronize supply with demand as closely as possible, ideally one customer request at a time. The human heartbeat doesn’t like to batch and queue, but also speeds up and slows down in healthy and unhealthy ways – it’s the same in business.
Hi Jamie
Good reflection. I would take it a step further and simply define takt time as “the beat”. As you pointed out the time window and customer demand will vary greatly depending on whether the process is repetitive manufacturing, retail, healthcare or education. The idea is to synchronize supply with demand as closely as possible, ideally one customer request at a time. The human heartbeat doesn’t like to batch and queue, but also speeds up and slows down in healthy and unhealthy ways – it’s the same in business.
Hi Jamie
Good reflection. I would take it a step further and simply define takt time as “the beat”. As you pointed out the time window and customer demand will vary greatly depending on whether the process is repetitive manufacturing, retail, healthcare or education. The idea is to synchronize supply with demand as closely as possible, ideally one customer request at a time. The human heartbeat doesn’t like to batch and queue, but also speeds up and slows down in healthy and unhealthy ways – it’s the same in business.
“Lean isn’t easy”
People say to me that my job as a Lean Lead is easy, or not a “real” job. If only they knew!!
“Lean isn’t easy”
People say to me that my job as a Lean Lead is easy, or not a “real” job. If only they knew!!
“Lean isn’t easy”
People say to me that my job as a Lean Lead is easy, or not a “real” job. If only they knew!!
I don’t think it is the most misunderstood because people often get close to understanding it correctly – while some things like respect for people they often don’t come remotely close to. Understanding 80% of takt time puts you ahead of the understanding of many (maybe most other lean ideas).
There are a several good articles on takt time recently at http://theleanedge.org/ I think Jeff Liker’s is particularly good http://theleanedge.org/?p=3436
I don’t think it is the most misunderstood because people often get close to understanding it correctly – while some things like respect for people they often don’t come remotely close to. Understanding 80% of takt time puts you ahead of the understanding of many (maybe most other lean ideas).
There are a several good articles on takt time recently at http://theleanedge.org/ I think Jeff Liker’s is particularly good http://theleanedge.org/?p=3436
I don’t think it is the most misunderstood because people often get close to understanding it correctly – while some things like respect for people they often don’t come remotely close to. Understanding 80% of takt time puts you ahead of the understanding of many (maybe most other lean ideas).
There are a several good articles on takt time recently at http://theleanedge.org/ I think Jeff Liker’s is particularly good http://theleanedge.org/?p=3436
Sorry, Jamie, but, when you say that takt time is synonymous with customer demand rate, you make it appear first that it is unrelated to the amount of time you work, and second that it is a rate and not a time.
If it were the customer demand rate, it would not be affected by the number of shifts you work. But, in reality, if you go from one to two shifts/day, you double your takt time without any change in the customer demand.
Why does it matter that it is a time and not a rate? If you produce at a rate of 60 units/hour, it doesn’t matter if none come out for the first 59 minutes, and all 60 finish during the last minute, and factories designed to produce at a rate of 60 units/hour reflect this. On the other hand, if you work at a takt time of 1 minute, it means that you complete one unit every minute, and factories designed to produce exactly one unit every minute do not look like factories designed for 60 units/hour.
Otherwise, I agree with you that the formula used to calculate takt time should not contain an explicit unit like shift, because you can use whatever time period is relevant. In computer assembly, you may use a shorter period; in shipbuilding, a longer one
Sorry, Jamie, but, when you say that takt time is synonymous with customer demand rate, you make it appear first that it is unrelated to the amount of time you work, and second that it is a rate and not a time.
If it were the customer demand rate, it would not be affected by the number of shifts you work. But, in reality, if you go from one to two shifts/day, you double your takt time without any change in the customer demand.
Why does it matter that it is a time and not a rate? If you produce at a rate of 60 units/hour, it doesn’t matter if none come out for the first 59 minutes, and all 60 finish during the last minute, and factories designed to produce at a rate of 60 units/hour reflect this. On the other hand, if you work at a takt time of 1 minute, it means that you complete one unit every minute, and factories designed to produce exactly one unit every minute do not look like factories designed for 60 units/hour.
Otherwise, I agree with you that the formula used to calculate takt time should not contain an explicit unit like shift, because you can use whatever time period is relevant. In computer assembly, you may use a shorter period; in shipbuilding, a longer one
Sorry, Jamie, but, when you say that takt time is synonymous with customer demand rate, you make it appear first that it is unrelated to the amount of time you work, and second that it is a rate and not a time.
If it were the customer demand rate, it would not be affected by the number of shifts you work. But, in reality, if you go from one to two shifts/day, you double your takt time without any change in the customer demand.
Why does it matter that it is a time and not a rate? If you produce at a rate of 60 units/hour, it doesn’t matter if none come out for the first 59 minutes, and all 60 finish during the last minute, and factories designed to produce at a rate of 60 units/hour reflect this. On the other hand, if you work at a takt time of 1 minute, it means that you complete one unit every minute, and factories designed to produce exactly one unit every minute do not look like factories designed for 60 units/hour.
Otherwise, I agree with you that the formula used to calculate takt time should not contain an explicit unit like shift, because you can use whatever time period is relevant. In computer assembly, you may use a shorter period; in shipbuilding, a longer one
Being somewhat outside the core of Lean, I have heard takt time used exactly the way you say people get it wrong. But doing some basic reading points me in the direction you have discussed here: takt time depends on the (customer) demands.
The question I have then is on how people use this information to make decisions. Do we need to design systems to be capable of handling the lowest known / expected takt times, and then adjust when the demand is lower? Does the answer change if the demand is quite variable?
Thanks!
Being somewhat outside the core of Lean, I have heard takt time used exactly the way you say people get it wrong. But doing some basic reading points me in the direction you have discussed here: takt time depends on the (customer) demands.
The question I have then is on how people use this information to make decisions. Do we need to design systems to be capable of handling the lowest known / expected takt times, and then adjust when the demand is lower? Does the answer change if the demand is quite variable?
Thanks!
Being somewhat outside the core of Lean, I have heard takt time used exactly the way you say people get it wrong. But doing some basic reading points me in the direction you have discussed here: takt time depends on the (customer) demands.
The question I have then is on how people use this information to make decisions. Do we need to design systems to be capable of handling the lowest known / expected takt times, and then adjust when the demand is lower? Does the answer change if the demand is quite variable?
Thanks!
Jack, yes, the answer does change in the demand is quite variable. That’s why the first question must be the time horizon you are looking to make decisions about. If you’re looking to decide how many burgers to put on the grill, you want to figure out your takt time over a period in which burgers would get cold, or how you would staff the lunch time. But if you were looking to decide how many stores to build, you might be looking at demand rate over a year.
Regarding the first part of your question, do you design for the lowest takt time and adjust, it depends on the investment required. Many businesses that really want volume such as food retail would staff to whatever level possible to handle the highest volume, because they need to serve this to make up the rest investment. But if capital intensive, you might build to the median and forgo the peak. For example, the power generation space, if it wasn’t regulated, no power company would build power generation just for the 95 degree days.
I hope that helps Jack.
Jack, yes, the answer does change in the demand is quite variable. That’s why the first question must be the time horizon you are looking to make decisions about. If you’re looking to decide how many burgers to put on the grill, you want to figure out your takt time over a period in which burgers would get cold, or how you would staff the lunch time. But if you were looking to decide how many stores to build, you might be looking at demand rate over a year.
Regarding the first part of your question, do you design for the lowest takt time and adjust, it depends on the investment required. Many businesses that really want volume such as food retail would staff to whatever level possible to handle the highest volume, because they need to serve this to make up the rest investment. But if capital intensive, you might build to the median and forgo the peak. For example, the power generation space, if it wasn’t regulated, no power company would build power generation just for the 95 degree days.
I hope that helps Jack.
Jack, yes, the answer does change in the demand is quite variable. That’s why the first question must be the time horizon you are looking to make decisions about. If you’re looking to decide how many burgers to put on the grill, you want to figure out your takt time over a period in which burgers would get cold, or how you would staff the lunch time. But if you were looking to decide how many stores to build, you might be looking at demand rate over a year.
Regarding the first part of your question, do you design for the lowest takt time and adjust, it depends on the investment required. Many businesses that really want volume such as food retail would staff to whatever level possible to handle the highest volume, because they need to serve this to make up the rest investment. But if capital intensive, you might build to the median and forgo the peak. For example, the power generation space, if it wasn’t regulated, no power company would build power generation just for the 95 degree days.
I hope that helps Jack.
I know the post was on takt time and it was spot on, but I really like your statement that lean is not common sense. I agree. Lean is not common sense, but most of the time when the lightbulb does turn on with a new thought like the one about takt timenit stops you in your tracks. You smack you head and think, “Oh yeah. That does make sense!”. It just isn’t common sense or like you said everyone would be doing it.
I know the post was on takt time and it was spot on, but I really like your statement that lean is not common sense. I agree. Lean is not common sense, but most of the time when the lightbulb does turn on with a new thought like the one about takt timenit stops you in your tracks. You smack you head and think, “Oh yeah. That does make sense!”. It just isn’t common sense or like you said everyone would be doing it.
I know the post was on takt time and it was spot on, but I really like your statement that lean is not common sense. I agree. Lean is not common sense, but most of the time when the lightbulb does turn on with a new thought like the one about takt timenit stops you in your tracks. You smack you head and think, “Oh yeah. That does make sense!”. It just isn’t common sense or like you said everyone would be doing it.
John Hunter: I realized I missed your comment for a response.
I agree that the DEGREE of misunderstanding is the greatest, but I think the FREQUENCY os misunderstanding is the highest. In a sample size between 100-200 people, I’ve seen greater than 90% think that the takt time is the rate at which you produce, not the rate at which the customer pulls.
There are probably many concepts that have a great degree of misunderstanding. So folks, what would that one be?
John Hunter: I realized I missed your comment for a response.
I agree that the DEGREE of misunderstanding is the greatest, but I think the FREQUENCY os misunderstanding is the highest. In a sample size between 100-200 people, I’ve seen greater than 90% think that the takt time is the rate at which you produce, not the rate at which the customer pulls.
There are probably many concepts that have a great degree of misunderstanding. So folks, what would that one be?
John Hunter: I realized I missed your comment for a response.
I agree that the DEGREE of misunderstanding is the greatest, but I think the FREQUENCY os misunderstanding is the highest. In a sample size between 100-200 people, I’ve seen greater than 90% think that the takt time is the rate at which you produce, not the rate at which the customer pulls.
There are probably many concepts that have a great degree of misunderstanding. So folks, what would that one be?
Without a doubt, the understanding of why product families are important for lean and the fundamentally product family-oriented metric of Every Part Every (EPE, EPEI, EPEc, EPEx, etc). We can’t even agree on what to call it!
I run into lots of lean consultants who have never heard of it and even fewer who understand its purpose and usefulness.
Without a doubt, the understanding of why product families are important for lean and the fundamentally product family-oriented metric of Every Part Every (EPE, EPEI, EPEc, EPEx, etc). We can’t even agree on what to call it!
I run into lots of lean consultants who have never heard of it and even fewer who understand its purpose and usefulness.
Without a doubt, the understanding of why product families are important for lean and the fundamentally product family-oriented metric of Every Part Every (EPE, EPEI, EPEc, EPEx, etc). We can’t even agree on what to call it!
I run into lots of lean consultants who have never heard of it and even fewer who understand its purpose and usefulness.
@Jack Vinson — You asked how takt times were used to make decisions. The takt time of a production line defines an ideal state, in which:
1. Each unit of product leaves the last operation at fixed intervals calculated to meet the demand within the production time available.
2, At all upstream operations, components and subassemblies instantly move to the next operation at the same fixed intervals.
Some call it True North. It is concise, but not descriptive. I prefer to call it Takt-Driven Production. It is an ideal that doesn’t exist but is closely approximated in moving assembly lines, and you can note that every deviation from it that you can observe in real production lines falls within Ohno’s waste categories.
It is also an ideal that is approached globally by doing it locally everywhere.
One immediate use for this concept is as a means of determining whether a local project actually improves the performance of the whole line, by asking whether it moves it in the direction of takt-driven production.
In a green field situation, you are designing a new plant or a new production line, and the first thing you need to know is what takt time you should design it for, the second one being what product or family of products it is intended for. This information drives everything about the design, from the way you break down the process into operations to the level of automation. For example, if your takt time is under 1 second, as happens with detergents, foods, or mass market toiletries, you have to automate. If it is more than 10 minutes, you can have manual operations, but you have to deal with the problems people have remembering long sequences of tasks… If it is 6 months, as in shipbuilding, you assemble a series of vertical sections of the hull in a production line and weld them together in the dry dock, an approach first developed for Liberty Ships in World War II.
For details, see Lean Assembly .
@Jack Vinson — You asked how takt times were used to make decisions. The takt time of a production line defines an ideal state, in which:
1. Each unit of product leaves the last operation at fixed intervals calculated to meet the demand within the production time available.
2, At all upstream operations, components and subassemblies instantly move to the next operation at the same fixed intervals.
Some call it True North. It is concise, but not descriptive. I prefer to call it Takt-Driven Production. It is an ideal that doesn’t exist but is closely approximated in moving assembly lines, and you can note that every deviation from it that you can observe in real production lines falls within Ohno’s waste categories.
It is also an ideal that is approached globally by doing it locally everywhere.
One immediate use for this concept is as a means of determining whether a local project actually improves the performance of the whole line, by asking whether it moves it in the direction of takt-driven production.
In a green field situation, you are designing a new plant or a new production line, and the first thing you need to know is what takt time you should design it for, the second one being what product or family of products it is intended for. This information drives everything about the design, from the way you break down the process into operations to the level of automation. For example, if your takt time is under 1 second, as happens with detergents, foods, or mass market toiletries, you have to automate. If it is more than 10 minutes, you can have manual operations, but you have to deal with the problems people have remembering long sequences of tasks… If it is 6 months, as in shipbuilding, you assemble a series of vertical sections of the hull in a production line and weld them together in the dry dock, an approach first developed for Liberty Ships in World War II.
For details, see Lean Assembly .
@Jack Vinson — You asked how takt times were used to make decisions. The takt time of a production line defines an ideal state, in which:
1. Each unit of product leaves the last operation at fixed intervals calculated to meet the demand within the production time available.
2, At all upstream operations, components and subassemblies instantly move to the next operation at the same fixed intervals.
Some call it True North. It is concise, but not descriptive. I prefer to call it Takt-Driven Production. It is an ideal that doesn’t exist but is closely approximated in moving assembly lines, and you can note that every deviation from it that you can observe in real production lines falls within Ohno’s waste categories.
It is also an ideal that is approached globally by doing it locally everywhere.
One immediate use for this concept is as a means of determining whether a local project actually improves the performance of the whole line, by asking whether it moves it in the direction of takt-driven production.
In a green field situation, you are designing a new plant or a new production line, and the first thing you need to know is what takt time you should design it for, the second one being what product or family of products it is intended for. This information drives everything about the design, from the way you break down the process into operations to the level of automation. For example, if your takt time is under 1 second, as happens with detergents, foods, or mass market toiletries, you have to automate. If it is more than 10 minutes, you can have manual operations, but you have to deal with the problems people have remembering long sequences of tasks… If it is 6 months, as in shipbuilding, you assemble a series of vertical sections of the hull in a production line and weld them together in the dry dock, an approach first developed for Liberty Ships in World War II.
For details, see Lean Assembly .
[…] out Jamie’s explanation of takt time and what it means at his website. Share this:PrintEmailFacebookLinkedInTwitterLike this:LikeBe the first to like this […]
[…] out Jamie’s explanation of takt time and what it means at his website. Share this:PrintEmailFacebookLinkedInTwitterLike this:LikeBe the first to like this […]
[…] out Jamie’s explanation of takt time and what it means at his website. Share this:PrintEmailFacebookLinkedInTwitterLike this:LikeBe the first to like this […]
My question is, my takt is 23 build groups a day but we only got 20 today so tomorrow my Forman moves 3 units out of our swip and work stations and moves them ahead causing 3 empty spots on the line causing the workers to build new ones to replace the 3 he (stole) witch means they have to catch up with the line to eventually put everything back in its place as if nothing happened. Our takt time rules clearly say we are not to do this but they always have some reason why its ok for m to break the rules all though in the past we were threatened with disciplinary action for moving a head. How should this be done correctly ?
Burt,
Good question. I should start by saying that I’m very cautious offering advice on a situation that I haven’t seen for myself. Both the physical and cultural aspects of any environment are very complex.
Rules are made to be broken. I’ve never met an organization that isn’t willing to break its own rules, including Toyota. These aren’t rules of physics – they are man-made rules. The purpose of rules is to force certain behaviors, and then good judgement should be used when those behaviors aren’t the right thing for the specific situation. The important thing is to always know why you are breaking the rules, and knowing the consequences of doing so.
In this situation, it sounds like the person doesn’t understand the consequences. Theoretically, I wouldn’t be behind my customer demand today if we hadn’t stolen units ahead yesterday. This does NOT sound like a productive solution. However, you do need some mechanism to handle loss. It could be overspeed, so if you are behind every day your process is not yet capable of building 23 based on a schedule of 23, so you need to plan on building 23 to get 26. Yes, this is technically waste but it is also pragmatic (and just to cover the point, Toyota does this systematically). This is harder to do if some days I can build 30 and other days 15. Even if I’m not capable of hitting the target, if it’s generally a steady and stable loss it is easier. Overtime and resource shifting is also used, so we will build 23 today whether it takes us 8 hours or 10 hours. This is quantity control. I don’t know the specific solution without having seen your situation, but to give your foreman the benefit of the doubt, if he doesn’t have a solution to meet customer demand, he is trying to work around the situation.
Jamie
Jamie, Great info.. I am pretty new to this, but did have a question. What would be the outcome if Takt time is greater than cycle time? Would it cause excess iventory? no inventory? bottleneck? Thanks in advance for your help!
Chris, when your cycle time is faster than your customer, then you basically have three choices (unless you want to generate a whole lot of waste). Ideally, the market is now the constraint, so you go after and increase demand, which shortens your takt time. Or, you just stop producing or slow it down so that you don’t overproduce. Or, if it’s more permanent, you de-asset the process to reduce the cycle time to better match the customer demand rate.
Could anyone help me for my request.
Example – My takt time is 2.89 secs(for hourly output of 1246), Total cycle time is 34 secs, total no of process is 15, highest process cycle time is 3.8 secs. for your information my standard required persons is 15, but if i calculate for optimum person required as per standard ( total cycle time/ takt time) 34/2.89 = 11.7 ~ 12 persons. but in reality its not feasible to operate with 12 persons. Is it right or am i doing any mistake.
Great Article,
The Takt Time is a limit that should hell you to understand where you are and where the Company has to go.
We would like to suggest our Takt Time simulator just to get practice.
http://www.leanlab.info
If I’ve got a department that has several different product that it runs and the demand and fulfillment dates for each product varies from day-day week-week month-month, how would I look at TAKT time? Would it be per product? Would I have to calculated it based on an average fulfillment time or something like a min/max?