“Takt Time” For a Warehouse – Lean Supply Chain Kaizen

To calculate Takt Time in manufacturing, you divide available production time by the number of products to be made (Customer demand), which tells you the time available to make one product (The Rhythm of Production). On the Warehouse Operations is not calculated in exactly the same way as manufacturing, but the concept is similar.

Its very important to mention that ones the Takt Time on Warehouse operation its very well understood, helps the Warehouse Managers to manage the daily operations, they are capable to know how long it takes to put away the different types of parts received in a shipment, how many parts must be put away in a day, how rapidly the parts must be put away to get the work done and what staffing level is required to achieve that.

For Warehouse the Takt Time calculation occurs, as follows:

The table below shows an example of the work to be done in a given time shift. In this case, parts are sorted into three categories, based on size. This sorting makes it possible to know how many parts can be away in 20 minutes.

The “X” numbers in the first column represent the commodity codes used to sort the products. The term “Lines” refers to how many line items in a particular category must be put away.

The formula for calculating Put – away assignments is

Lines / Put-away Qty. = Put-away assignments.

Which in this case becomes

(300 / 10) + (300/15) + (760/20) = 88 Assignments

Calculation of the Put-away Pace  (Takt Time) is

Takt Time (Put-away Pace) = [Shift Time (minutes)] / [Assignments] = 440 / 88 = 5 Minutes.

Or 

Takt Time (Put-away Pace) = [Available Time (minutes)] / [Demand Assignments] = 440 / 88 = 5 Minutes.

The required number of people is then calculated by dividing Put-away Time  (20 minutes) by the Put-away Pace (5 minutes), which determines that people are needed for this shift.

People Required = Put-away Time / Put-away Pace = 20 / 5 = 4

This is one example to give you the concept to calculate your own Warehouse Takt Time.

I hope this help you.

Takt Time vs Manual Cycle Time: The method to calculate the Quantity of Operators.

This article was written based on my experience as consultant.

After many Kaizen event I have found there is 2 misunderstandings about how calculate the Number of Operators that are needed to run a production line or manufacturing cell.

When you implement standardized work a Takt Time base on customer demand must first be established for the area in question, for example 30 seconds TT, this is equal to set a rate of 120 UPH (Units per Hour).

Therefore; the next question is how many workers are needed in the manufacturing area, at this rate?

The answer depends on the total work content in the area and relation to demand ( TT).

It's also known as graph of “Takt Time vs Manual Cycle Time”, in many industries.

The more work content, the greater the number of workers that will be required; the less overall work content, the fewer workers that are needed.

Misunderstanding 1: 

I have found there is a misunderstanding of Overall Work Content, many people take the Cycle Time complete (Machine + Manual) and that is not ok, they must use the “Manual” Overall Work Content (Total Manual Cycle Time)

Please see this example.

The calculation shows that is possible to run this Manufacturing Cell with just 3 operators. 

Misunderstanding 2:  

There is other misunderstanding this is about the representation of TT, many people don’t understand this concept how interpret and calculate the Quantity of operators when they have operators working in parallel.

For example; when there are operations that are not possible to be separated, the activity must be done from the start to the end by one operator at time; and if the cycle time is greater than Takt Time; then you need use more than one operator to cover the rate needed, this means to have two or more operators working in parallel, for this case the Takt Time must be different.

You should never use the average of those operators as the Manual Work Content, you need represent as it is and make the calculations using other Takt Times equivalent.

Please see this example.

The calculation shows that is possible to run this Manufacturing Cell with just 5 operators; please note that here there is two Takt Times, but don't get confuse at the end the Cell will run at 30 Seconds of Takt Time; equivalent to 120 UPH. The operators 1 and 2 must works at 3 process in sequence  (Press, Trim and Spring).

I hope this be useful for you in your next Kaizen event.