Takt Time

Takt time is the rate at which products or services should be produced to meet the customer demand. The value, in conjunction with current loading (production) rates, is used to analyze process loads, bottlenecks, and excess capacity.

The study will indicate which operations are ahead of the demand rate and others that are not, both indicating opportunities for improvement. This is strictly a formula and calculation. Use it to compare your measured "loading" to quantify whether an operation meets, exceeds, and by how much.

The numerator, Available Work Time, is often expressed as Minutes/Shift, Seconds/Day, Minutes/Day and so on.

The denominator, Customer Demand Rate, is often expressed as Parts/Min, Units/Shift, Pieces/Day, and so on.

Below is an example calculation. It is labeled PROCESS 1 because if the amount of work time available OR the demand on that particular machine or group of machines varies from one process to another then each process will have its own takt time.

Below is a video that calculates takt time based on daily time available (pay close attention to what defines "available")and the daily customer demand of good pieces.

If Customer A wants 55,000 units/day that require Process 1 (from above) and these units also require downstream Process 2

AND

Customer B now places an order and wants 55,000 units/day that require Process A and NOT Process 2 then the takt time for each process is different.

Given the work available is the same for each process at 22 hours/day = 1,320 minutes per day = 79,200 sec/day.

CALCULATION:

Process 1: Takt time = 79,200 sec/day / 110,000 units/day = 0.72 SEC/UNIT

Process 2: Takt time = 79,200 sec/day / 55,000 units/day = 1.44 SEC/PART

Conclusion

The load rate (production rate) must be twice as fast on Process 1 than Process 2 to keep up with customer demand.

Those operations that are performing better than takt time also have opportunity for improvement; often the load from a process that is behind can be offloaded and shared. The amount is determined by the differences in the current load and takt time studies for each process.

Leveling the workload, line balancing, across the processes by studying these values is the team's work. The study is normally depicted using bar graphs and will not only show bottlenecks or excess capacity but will quantify the amount and show relativity between all operations.

It may commonly be known by the team members which operations have capacity and which are the constraints but it is not known to what degree and amount compared to the other processes.

The study will only provide numbers. A small constraint in one area due to high scrap and rework may be much costlier overall than a larger time constraint in another area.

These numbers along with reasoning on costs, scrap, and other subjective measures are for the team to determine prioritization for the improvements.

The goal is to get the entire line balanced while removing waste. Waste reduction (rework, scrap, over production, and other 7-Wastes) should be targeted aggresively and and then a the takt time and loading study should be done prior to significant investments into line balancing.