Many have a hard time understanding what takt time is when it comes to Lean Manufacturing. In order to understand takt time, letâ€™s imagine that you are a young child, and you have a paper route that you do before you go to school. The papers get delivered an hour before you have to go for your classes. So it would appear that you have sixty minutes to deliver all of your news papers. However, if you think about it do your really have a full sixty minutes? Perhaps not.
We must remember you have to get your bike ready and load your papers on your bike. For this example let us consider you can roll your papers while youâ€™re pedaling your bicycle. You would also need to park your bike and put away your bag when you finish your route. So that hour really turns into more like fifty minutes.
Besides the time available, what else do you need to know to calculate the takt time for a newspaper delivery? Something else to consider is how many papers you actually have to deliver? Letâ€™s say you have twenty five houses on your route. You now have enough information for your takt time calculations.
50 minutes / 25 houses = 2 minutes per paper.
The amount of time you have to deliver each paper is your takt time and in this case it is two minutes.
How long does it take to deliver each paper? (This would be your cycle time.) If it takes you less than two minutes, on average, you are able to meet your demand. If it takes longer, you are not going to get to school on time.
When there is a process that is extremely stable, like on an assembly line, it is easy to pace to the takt time. The work advances at a set pace, so the product rolls off the end in very predictable increments. This isnâ€™t the situation with a newspaper route.
Why? Well, because there is a lot of variation. There are many variables like, the weather, the distance between houses. Some people like the paper placed neatly on the porch. Others donâ€™t mind having it placed somewhere in the vicinity of the door. Some driveways are long. Some houses are close to the street. Some of your customerâ€™s dogs are not so friendly, and so on.
On a paper route, or in the manufacturing plant, takt time works best as an average pace. Some papers get delivered quickly; others will take longer. Some phone calls can get resolved in a flash; others take a bit more time. But the law of large numbers eventually takes over. In many processes, you will find that every cycle is different, but any group of ten cycles looks an awful lot like any other group of ten cycles.
In manufacturing practice, or on your paper route, this allows you to use milestones or many times an actual digital take timer to keep on pace. If your takt time is two minutes for a process with variable inputs, you might use an hourly takt timer. You know you have to get thirty cycles done every sixty minutes. And when a team starts falling off the pace, and can recognize it early on by looking at the takt timer, leaders can make plans to get things back on schedule.
Things get even more confusing when there are cyclical changes in demand. Imagine that your local newspaper decides to offer a Sunday only delivery option, and 25 more houses on your route elect to get this big, unwieldy edition. Two things happen, right? First, you now have fifty minutes to deliver to fifty houses, a drastically reduced takt time of one minute. Plus, the Sunday paper is bulky and is harder to bundle up; and you just canâ€™t carry as many on your bike. Even worse, you canâ€™t toss a Sunday edition because the rubber band would break and create a mess. Your cycle time goes up at the same time that your takt time drops.
One option is to group your demand into different periods, for example, a Sunday takt time and a weekday takt time. No problem. You just have to get creative on how you staff for the different periods. Fast food restaurants adjust their staff throughout the day, as they know the pace picks up during mealtimes, and slows down the rest of the day. Whether they call it takt time or not, they end up matching their capacity to the required pace. On your paper route, you might do the same thing by hiring a friend to help you meet your Sunday demand, or you could work a longer shift.
So, let us get back to your paper route. Letâ€™s assume that you want to earn more money by adding more customers to your route. Can you handle the load? The answer lies in being able to understand how fast you need to be able to work to meet the new demand.
Letâ€™s see what happens if you add five houses to your route. Again, pull out your trusty takt time calculation.
50 minutes / 30 houses = 1:40 per paper
You would have to be able to deliver the paper at each house 20 seconds faster than before.
So, takt time serves to give you a real target for improvement, not just an arbitrary, made-up percentage. If it currently takes you 1:52 (112 seconds) per paper, youâ€™d need an 11% reduction in your cycle time to meet your planned customer demand. (Cycle time is how long a process actually takes to complete. You reduce it by applying generous portions of continuous improvement.) Goals with a specific purpose are always easier for front-line employees to get behind than annual improvement goals (i.e. improve productivity by 10% per year).
Are you starting to see how takt time can improve your production?
This guest post was written by Rick Shoop of Alzatex Lean Manufacturing Timers – We recommend their products wholeheartedly Thanks Rick!