Takt time = available production time per day/customer demand per day
You need to know two things about takt time:1. The math, 2. Takt time is about people not math
Why is takt time important?
Takt time is the beat of the customer. Produce less and you cannot meet customer demand. Produce more and it is overproduction.
You cannot truly implement flow and pull if you are working with your own idea of customer demand. A lot of companies also produce according to their own capacity instead of their customers needs. This usually leads to problems in the value stream. Your value stream needs to be tuned in to actual customer demand in order to be able to reduce waste and increase value.
When you work according to takt time problems in the value stream will become visible when they occur. When there is a problem in the value stream, there will be no inventories to fall back on and work will come to a halt.
Why is it so difficult to start producing according to takt time?
When people do not work according to takt time, they will not see the need to change this. Takt time takes away a lot of tolerance for defects and inventory. This tolerance for defects and inventory make people feel comfortable. If they make a mistake it does not really matter, because you can move on to the next thing and fix it later. When you work to the beat of takt time people fear that there is no room for error. Because when something goes wrong you the entire value stream grinds to a halt.
In companies that are working with batch production the idea of stopping the value stream to fix a problem sounds counter-intuitive. Why stop the value stream, when you could be working on other parts in your inventory? Why stop the value stream, if the customer is waiting for their product? It feels like a waste of time to work to takt time.
When you start to work according to takt time, it means that you want to balance the cycle times along the value stream. This may mean that processes that were separate get joined. It may also mean that processes that were together get separates. This tends to go against internal logic.
Another well known objection is that producing to takt time will require a lot of standardization. This will make the work less attractive for employees. They will feel restricted and get bored.
So from an old school view, producing to takt time will lead to organizational change in order to produce less, have production failures more often than before and annoy your employees.
What makes takt time work
As you can see takt time is a bigger change than it may seem at first and that is just by looking at the numbers and the value stream. When people oppose this change i usually ask them the following questions:
The costs of a new way of working are immediately clear. The costs of the current situation are accepted as a given, as normal. When people look at takt time this way they are missing the most important thing about lean.
Lean is a human centered approach. It trusts people do to their job well . It assumes that when something goes wrong it comes from bad processes or machines. Employees deserve to have a workplace where they do not have to work around defects or faulty processes. They deserve a work place where they do not have to struggle, where they are given the resources and time to solve problems at the root cause.
Central to the idea of takt time is trusting your employees. When you take all waste out of your processes, you take away struggles for your employees and your customers. Without takt time true flow and pull will not be possible.
How to implement takt time?
Imagine that your value stream looks like this:
The blue blocks show the cycle time of each process in the current state. The green line shows the takt time. What do you do?
Look at physical lay out
Go to the gemba and look for these things:
Use you imagination and respect the input of the employees. Ask them where they struggle. Where they feel they are being made to do useless tasks.
Look for wastes inside and between processesThe 8 wastes (TIMWOODS)
Go to the Gemba and look for wastes inside processes. This can help you reduce cycle time. If you want to test your knowledge on TIMWOODS, you can take this fun quiz.
Look at the skills and tools needed to balance the line
You can also balance the line by changing tasks between processes. For this you need to analyze the skills, tasks and tools inside processes. You can use a skill matrix for this. Make sure to supply training in both job tasks and lean skills.
It may be possible to move tasks from process A to process B. Be sure not to do this if the skills, mindset or tools needed to do so are not there yet. The idea is to reduce struggle for employees, not to increase stress.
Successful improvement is done with people not to them
Who does the improving
Improvement is not done to employees. Employees improve the processes and as consultants and managers we get to help them. We can help by providing direction for improvement (goals, purpose) and by giving employees means to improve (time, resources, training).