Welcome, readers, to the long-awaited final chapter of our blog series about takt time. In my first post, I described what takt time represents- the average rate of customer demand. I talked about how to make takt time work for you in my second post. In this article, I’m going to go over a clever use of takt time and how it can guide process improvement efforts.
We can use the process time and the takt time to determine how many workstations, people, tables, etc. we need to meet customer demand, by simply dividing the process time by the takt time. Let’s say that a customer arrives at a fast food restaurant every 45 seconds (our takt time), and it takes approximately 180 seconds to process the order (our process time). Dividing 180 by 45 equals 4, so at least 4 cashiers are needed for each customer to make and receive their order without waiting in line to order.
A common question I get is: It takes longer than takt time to do the job. How can we work that fast?
I’ll use the graph below to depict this question and its answer. In this example, we have six employees whose cycle time (how long it takes to complete a task from start to finish) varies from 40 to 110 minutes, but our takt time is 60 minutes. Thus, employee A is meeting takt time, but the rest of the employees either have too much to do for their process or not enough.
First, we should make process improvements to reduce the time it takes for each employee. By analyzing the process, we can determine which steps are value-added (VA) for the customer (they would pay for it, it improves the process in some way, and it was done right the first time), which are business necessary (BN; required by regulations), and which are non-value added (NVA; these are not required and the customer would not pay for them). We’ll keep the VA and BN steps, and reduce the number and duration of NVA steps in our process improvement.
As you can see, this improved the situation somewhat but there is still an imbalance in workloads across employees. Workers A, D, and E are below takt time, worker B is right at takt time, and workers C and F can’t quite match takt time. We can create a balanced process by level loading (reallocating workload) and combining the work of employees D and E:
The process has now achieved its future state, as set by takt time! Through process improvement and improving the flow of the process (via level loading), we have reduced the cost of the process and freed up an employee to work on more valuable activities.