Traditionally, when setting labor standards and balancing an assembly line we have used the term ‘cycle time’ to specify the time available at each work station to accomplish the necessary operations (and meet production demands).
However, in recent years the German term ‘takt time’ has come into voge to mean about the same thing — produciton time available to meet customer demands.
Should we be replacing ‘cycle time’ with ‘takt time’ in our disucssions and literature?
Cycle time & takt time are not the same.
Cycle time for a process is the time it takes for that process step to be completed.
Takt time is the average demand from the customer & therefore the rate at which products should be produced.
I am not doubting your definitions.
If takt time is the average demand from your customer (assuming normality so 50% of the time they want more and 50% of the time they want less) and I produce at that rate how do I compensate for the 50% of the time that I am running to slow to satisfy the customers demands?
Ok I’ll bite on this thread.
Isn’t takt time the total time it takes for raw material to be recieved into the back door, be converted into finished good, and shipped to the customer? Also included is all the waiting points where the material better known now as WIP; and all the time it spends on the rack waiting as finished good to be shipped to the customer.
I can see takt time decreasing or increasing based on customer demand much the same way Inventory Turns do. The faster the customer pulls material from you the quicker your takt time must become. And the opposite is true if the customer slows his pull on your goods. This is where waste now sneaks into your factory; half finished production is now placed on hold or may its completed and stocked. You may even go all out to finish production runs to stock as finished goods if demands drop to stay efficienet with labor, but still your takt time suffers because finished good sit on the loading dock until you get a pull from the customer to stop the takt time clock. .
To have a little fun with takt time go to the recieving dock and pick a common piece of material that is processed in your shop and tie a dated tag to it. Follow the item through your shop until it is placed on the truck to the customer. The span ot time may be amusing or it may be down right shocking.
Boy don’t I hate responding to a Carnell thread!
According to “The Lean Enterprise Memory Jogger” from Goal QPC page 165, that I recieved for my subscription to the iSixSigma Magazine (and the only Lean book I brought with me) the definition is: “The total available work time per day (or shift) divided by customer-demand requirements per day (or shift). Takt time sets the pace of production to match the rate of customer demand. For example ……”.
Cycle time (according to Goal QPC page 158) is: “The time it takes to successfully complete the tasks required for a work in process.”
I was really reacting more to the proposed calculation that used only averages and ignored the standard deviation of both the customer and the manufacturing process. Without understanding the variation it seems to be prone to causing you a problem about 50% of the time. Just one of those things when you read them doesn’t sit well.
You have wounded me deeply with your last comment. I am a pretty sensitive guy.
Hey Mr C.
I wasn’t out to wound you..I just knew you were going to set me straight…as you usally do.
Just when I get to thinking I am starting to understand you ask a question and I have to look it up.
You sound like you have been working on this stuff pretty hard. The possums will feel neglected.
Mike, I fully agree that without some probabilistic consideration for varying process and demand, the calculations for takt are very gross and not really useful for detailed analysis. Another reason to drive out variation in the process. I am sorry, you have only shown to be sensitive before noon, after that you can be quite testy. That’s good for the posters overseas who post between 2-4 am but not for those of us posting in US time. You have been very prolific today…guess you weren’t able to get an early tee off time.
If I may (for the first time) respond. I run into this conflict between Six Sigma and Lean quite often. Though BB’s then to take a very analytical approach to things of this nature. Lean is not quite as disciplined when it comes to statistics.
Takt time is pacing like the beat of the drum experienced by oarsmen on a Roman Galley. Beat faster row faster, beat slower row slower. It defines the pace of the process to meet the customer orders. It does not express any notion of product quality or wheither you operate at, above or below capacity. Or even make a profit for that matter. It is merely one metric of many.
Cycle time is process time plus wasted efforts (variation included). As we all know, many of the 6s x’s are rooted in the same drivers of “lean” wastes.
Perhaps, the difference is somewhat subtle, but you can have a good takt time, and have very poor cycle time(a lot of waste). Variation in takt time is bad, variation in cycle time is bad. Both are Y’s.
Looking forward to more discussion
Sick Ma people discriminately to apply variation to anything under the sun.When you set your takt time, the upper limit always shall be used instead of average and standard deviation. You cannot produce your product or sevice longer than takt time. Takt time MUST be your upper limit if you do not want to screw up your customers.Try talk to Dell or Toyota people that your chance of delivering a shipment in time is 50%. They kick you out from their office on the spot!You will be disqualified by Dell for missing three JIT shipments.
What happens if the line produces at the upper limit of the takt time rate and actual demand is less? Does the line slow down? Is there a build up of WIP? Is there idle time? And by the way, variation is a fact of life for everything under the sun. Whether you chose to recognize it or adjust for it is your choice. Whether it is critical or not depends on the situation. But you can’t ignore it.
There is a lean concept call production levelling to mitigate production fluctuation problem.No customers will bother your internal inherent “variation” or waste issue. You have to solve it yourself and not using your incapability to solve it as your excuse. Dell will not pay you for whatever you build and keep in the store and truck on the road for your “just in case” scenario. That is your own internal bleeding variation problem!
Oop…discriminately shall read as indiscriminately.”Sick Ma people discriminately to apply variation to anything under the sun.”
Takt time is most relevant when designing a production process.
If you have 8 hours of work time a day, and a customer demand of 8 units, takt time is 1 hour.
This means that no individual process can exceed the 1 hour. When designing the production process you have to take into consideration that customer demand will fluctuate. So you then design the proccess into logical break points where more people or equipment can be put on line to match customer demand.
Typically, the rate of work should be steady, and individual cycle times should remain fairly constant. If cycle time are pushed up to meet demand, that is typically an invitation for quality problems.
Actually it is staying up late enough to wait for Scot to get out of bed so I can discuss todays issues before I get comfortable at poolside for a quiet drink.
It has been a tough day running around applying variation to all manner of things. We are definately concerned that the ore we mined today won’t make it to Dell on time. (It is a good thing our Lean guy is from Dell or I sure would never have figured this stuff out).
I have yet to hit your level of notariety where the posting come so rapid fire that other people actually track the time.
I always wondered why people were telling me to get the lead out when I did calculations on my Dell laptop. It was also real heavy to schlep around. Now I understand.
For your information you posted 6 within 63 minutes or 1 per 10.5 minutes which would, at that pace, be 137 per day. That assumes you would have no rework otherwise we would have to do a RTY calculation. Of course points are deducted for poor grammar and spelling. Only partial credit is given for insults and useless or incorrect information. A full post deduction is made if you make any reference to Minitab or carelessly copy and paste. Any reference made to “New to Six Sigma” to the left will result in a 1.5 shift in your mean posting score. Hope this clarifies. Be sure you put on your sunblock.
As Mike provided the definitions of Takt time and cycle time, and AP noted the two are NOT the same. However, there is a relationship between the two.
In simple terms, takt time is the rate at which I need to produce (as set by your customer). With an evenly balanced process, each process step must produce at this rate so that the output of the process meeting this demand. Cycle time is the time that each process step ACTUALLY operates at.
Given those two factors, in order to meet your customers needs the process must be designed such that your individual cycle times are at or below takt time. If they in excess of the takt time, then the process will not be able to meet the customer’s needs and therefore needs to be improved.
Since customer’s needs vary, takt time will vary as well. If the customer’s needs decrease for a relatively short period of time (takt time goes up) then the process is capable of meeting the customer’s needs before “the end of the day”. In a lean environment, this “spare time” would then be used to do some other activities (redeploy personnel to another process that is not operating up to the customer’s needs, 5S, work on process improvement of that line, etc.).
If the customer’s demand increases for a relatively short period of time (takt time goes down) then the process in NOT capable of meeting the customer’s needs before “the end of the day”. However, in a properly designed LEAN process the process was designed to operate at takt time during a single-shift, five-day a week work period. Hence, putting in some overtime to compensate and meet customer demand is prudent and warranted.
If the changes in demand are “permanent” then the process must be redesigned to meet this new customer requirement. In any case, takt time is not a permanent number. It changes for a variety of reasons (all due to the customer’s desires).
Hope that this helps in the discussion. EdG
Your calculation for takt are absolutely right taking an average demand is the wrong part. We take maybe a six month look ahead in orders that is the customer demand. Takt may change up to 8 times a year on some value streams.
In aerospace we had 9 different aircraft types one would be on a move rate of three a week some one a month each had an individual takt time based on the demand for that product.
The cycle time of each key stage or process was then evaluated if it was greater than takt you had to in goldratt terms exploit the constraint. You would create a yamazumi or line balance chart to identify the constrained stages from seeing this you can do many things .
Identify Value and Non Value add. eliminate the waste to get below takt. Introduce shifts on some stages or create identical stages called rate tooling. So you never under or overproduce as you are asking because the speed of your line increases and decreases with customer demand by flexing tooling positions and manpower.
Usually you had the luxury of one value stream getting faster as another slows down moving your manpower onto different contracts.
Hope you get this
All The Best
With all that lead in your laptop you need to make sure you don’t chew on it regardless of what type of response you have to deal with.
That penalty for spelling and grammer will kill my timing. My editors definately work overtime trying to convert anything I write into some form od recognizable English. Drove my translators in Chile crazy.
Take care. We need to talk.
Thank you for the information. I thought it was interesting that in the aircraft market your schedule would be that volatile that you would change as much as 8 times per year. I would have thought your demand would have been more stable than that.
Correct! In the same spirit, you might also want to mention the 3 M’s.
Mike, ya got my number and my DrDarth email address so contact me at your earliest convenience. Why don’t you just do like Deming did and spell everything phonetically? Saves a lot of time. I had a copy of his original draft of Out of the Crisis where he spelled that way. Tough reading. I was such an insightful guy, I tossed it out. Just think what it would bring on eBay today.
Please keep in mind that our operational definations may differ slightly from the norm. Cycle Time, Lead Time, and Takt Time are all distinct metrics for our business. Takt Time is indeed from what we believe is customer demand(forecasts, customer orders, sales goals, market forecasts, etc.)
In a perfect world, that’s where I come in, your cycle time should be equal to your takt time. The time it actually takes to produce something is the exact same time the “customer” needs you to produce it in. Obviously I’m only a Six Sigma Black Belt so my company is happy enough if the cycle time is below takt time which means I’m meeting customer demand but yet I’m overproducing which creates inventory.
When balancing a production process I use both cycle times and takt times, you must be thinking “huh”? I want the individual cycle times to be equal. I don’t want WIP, I don’t want operators working harder than others, I want the process to be equal throughout. I also want the cycle times to be equal to takt time. So if my “customer” needs my product every 4.5 minutes, my goal is that every step in the process(cycle time) is equal to 4.5 minutes. I meet Takt Time and my operators are doing the same amount of work. Remember the basics that your process is only as fast as the slowest cycle time.
If I’m not making sense, it’s because I work too close to Arkansas.
Missouri Black Belt
I guess every situation is unique.
I can’t agree that a perfect scenario is when takt time is equall to cycle time. You are then running a fine line to meet demand. If you have parts running on a machining center that have a cycle time equal to your current takt time ( and you are at capacity) you will have some trouble when your demand increases and takt time decreases.
If you are able to have all of your cycle times equall, you must have a fairly simple product line. Im my experience, we have simple assembly and packaging operations which are pulling from in house foundry, in house machining, and in house metal fabrication. In short, the cycle times are vastly different, but all operations must support customer demand.
Cyle time is usually not changeable, you can do some “lean” activities or split a process up, but eventually you get down to a “fixed” cycle time for an operation. If this, in every case, ends up being equal to your takt time, you have a very unique operation.
Your second paragraph leads me to beleive that you don’t have a complete understanding for takt time, cycle time, and line balancing.
Is your company actually “happy” that you are overproducing?
“If I’m not making sense, it’s because I work too close to Arkansas.
Missouri Black Belt”
(Calling the porch dogs…… AJ begins to bark…. Zig snarls and growls……) Watch it MoBB…… It’s two days ’til gun season here in Arkansas…. and I need to make sure my ought-six is still sighted in….. and the MO line is only a few hundred yards from here……
On a more serious note, you made sense…. but being from Arkansas, what do I know? And you are right. The “trick” to takt/cycle time is to have a balanced production line. The other trick is to have a wage/employment system to avoid certain pitfalls.
RubberDude Certified Grand Master ARKANSAS Holiday Inn Express Black Belt
Sounds like you either have a lot of “waiting” or a lot of WIP. I see holes in your statements. One of the goals of Lean is to have a balanced process that has Takt = Cycle.
Just a quick follow up:
Will our Cycle Time ever be equal to our Takt Time? Probably not. However, as we enter a project we want that to be our goal, why? Because if our Cycle Time > Takt Time, we have unhappy dealers. If our our Cycle Time < Takt Time, we have inventory. If I have to "error" one way or the other I'm going to make sure I'm meeting customer demand even if it means I have to keep a finished good warehouse. If Takt Time changes, if Customer Demand changes then by default our processes will need to change as well to accomodate. The more control I have over the processes then the easier it is to make adjustments as Takt time changes.
Balancing Cycle Time is not easy in our process, in fact next to impossible as 90% of our production is manual without a machine element. Balancing individual operators relies on skill level, attitude, ability, etc. My goal however should be balance accordingly. If my #10 guy is taking 8 minutes to do his job then what good does it do me to have the other guys with a 5 minute cycle time? That’s why we balance, will it be exact….won’t be in my industry that’s for sure.
Yep, our gun season is two days as well. Almost feels like a “holiday” around here. I spent 5 years working in Arkansas so all my Arkansas jokes are not meant to be taken seriously.
No my company is not happy I’m overproducing.
I thought I made that clear when I said “they are happy if my cycle time is less than takt time, BUT, it will cause inventory due to the overproduction” At this point my company is willing to have a finished good warehouse due to cycle time being less than takt time. Why? We feel safer to meet our customer demand, on time delivery.
I would be curious to hear your thoughts on what level you want your cycle time to be in relation to your takt time? Below, Above, Equal, Higher, Lower, Same….. If you don’t want it equal, where do you want it?
Cycle time is very much changeable. Takt Time is not changeable. I guess I could call Customer Service and have them refuse orders to lower my takt time, but I’m pretty sure the board of directors might not like that. Cycle time is very much changeable, obviously you may need to add manpower, additional machines, or even additional processes to increase capacity(lower cycle time). I’ve spent a career engineering and improving processes(cycle time), I would hate to find out now that I haven’t been able to change any of it.
MoBB, appx. where are you? I’m in NE Ark…. Mosquito capital of the galaxy. And don’t take my jokes too seriously either. I WILL defend my home state, but I will make light of it as well.
RubberDude – Certified Master Holiday Inn Express Black Belt
SouthEast Missouri… I used to work in NE Arkansas. Small world :) Used to work in Pocahontas, AR.
I guess I don’t understand what you refer to as “cycle”.
I look at this way. If I have several operations that take 1 min each,and also have 1 operation that takes 4 min. I would group the 1 min operations together with one worker, to balance with the worker that has a single 4 min.operation. So now, the cyle time for each operator is equal, and in line with takt time. But this is line balancing.
Cyle time is the amount of time that each individual step of the process requires. These “time blocks” are then grouped together as required between man power or work stations, to balance the line.
Throughput time, or process time through a work station should = takt time.
Please set me straight if this is not correct.
OK, so help me understand this…the first post was asking about how to define things and somehow the posts got to trying to figure out how to operate in a takt/cycle time world. Seems to me takt will change all of the time, even within the same takt if product specs change. It seems way too cost inefficient to run my business with cycle time (process) equal to or less than takt (input) if takt will change. I mean, I set an upper limit (cycle time) for the shortest takt, hire people, get materials and machines, then worry about when the takt will increase, thus leaving me with more people, material and machines than I need. Sounds like that depending on the industry, takt determines cycle time (specialized products), or as in an industry with a product where things don’t change that often, cycle time is equal to shortest takt. Am I rambling in the right direction?
Jonesboro….. actually, work in Paragould, 25 mi north of Jonesboro
Good, I know some rubber guys in Batesville. Not as smart, well educated, or good looking as you though..
Yeah…. those guys tried to hire me a few years ago. I’ll reserve any further comment…..
Your operational definitions are exactly that – yours and as long as it is a commonly understood metric in your facility there should not be an issue. Speaking to someone outside the company can be an issue if they are not the convention.
We saw it differently. We (Motorola Seguin Texas) defined product cycletime as the moment that a customer decided they wanted the product (A little ambiguous but that forces you to consider the ordering process) until the product arrived at the place the customer wanted it. Basically it was intended to cover the time a want, need or desire is identified until it is satisfied. It is your cycle time as percieved by your customer which is really the one that matters. At one point those cycletimes were painted on the wall of the plant by product by year. When you looked at the time lines you could see that across the plant that the manufacturing cycletimes were the shortest component of the product cycletime. It delivered the message that if you wanted to reduce product Cycletime (or as our customer refered to it – lead time you needed to address more than manufacturing.
We also had process cycletimes. Time to complete each operation. When you summed those up you had Takt time. When the sum of the cycle times was longer than the takt time your customer expected then you had a problem. When it was shorter we had various configurations that would let us slow down to match the customers takt time.
Just the way we did it.
At least your BB is not from the Conway Holiday Inn Express.
Picture your “product cycle time” as our “Product Lead Time” and it paints a very similar picture.
We utilize Takt Time in almost the same way. Overall, our Takt Time is so many units shipped per day, we’ve went a step further and caclulated the takt time of each process which adds up to the Takt time of how many units shipped per day.
More than likely, even though our operational definitions vary, many of the same metrics will be universal.
Stan, mjones gave me the lowdown on RubberDude and unfortunately, he isn’t any of those. Sorry RD but Jonesy is da Man in AR.
All ya all’s times will be off if MC don’t fix that darn clock and get off Bubba time and back on Yankee time. Good catch, Stan. Must of been the smart one from Silcone Valley…oh wait that was Helga with the silicon…no must of been the old one since he is older than Father Time.
You are correct, Darth. M is my sensei….. has been for years…. ASQ has gone to the porch dogs since he left AR…. As have other related.
Has he ever told you about breakfast with…. I think it was Figenbaum and…. some other “guru”?
Batesville – that was where the guy pulled out a big hunting knife on the production line and asked Mark if he knew why he brought his knife to work. Mark answered no. The answer was because they wouldn’tlet him bring his gun.
Paragould where we put the plant managers company car and country club membership into the COPQ measurement and he wouldn’t talk to us for the next month.
State color is camoflage.