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The Takt Time is the pulse of the company: it represents the customer demand and allows to define the pace of production.

## Introduction

Takt Time (derived from the term « Taktzeit », littéralement “cycle time” in German) is the customer’s consumption indicator. He represents the pulse of the company to produce at most just, no more, no less. It is at the heart of the logic of Just In Time.

This key data helps to control production and keep pace with customer demand.

## The calculation of Takt Time

The Takt Time is expressed in seconds, hours, days … and is calculated by reporting the opening time to the customer consumption :

Takt Time = Opening Time / Customer Consumption

• Opening time : corresponds to the opening time of the OEE.
• Consommation client : quantity of products sold during opening time.

Example :

The total time is 8 hours per day, to which we subtract breaks, meal and scheduled maintenance for a total of 1 hour less. Which corresponds to our opening time. The client request is 500 pieces per day. The Takt Time is therefore 7 hours / 500 parts, ie 50.4 seconds.

## Takt Time VS Machine Leading VS Taylorism

To determine the rate of production, we have 3 approaches :

• Taylorism : pushes the operational to the maximum of their capacity by taking a standard level of performance on the bet operator.
• Le Machine Leading : produce the maximum capacity of the equipment without worrying about customer needs or team capabilities.
• Le Takt Time : determine the pace on the customer’s need.

A parody of the Machine Leading concept

## Takt Time and process design

Takt Time is an aid to the design or redesign of a process by allowing us to size it to the fairest.

### Case 1: Using Takt Time for New Equipment Design

We will use a calculation via “capacity reserve” . Having no history on this production, as much on our capacities to produce it as on the request of the customer, we will take a margin of safety on the value “ a priori ” of the request of the customer :

• For an automatic process, it is necessary to use a Takt Time increased by 5% (TT5) à 20% (TT20) to ensure a reserve of sufficient capacity and to cover exceptional causes: no quality, breakdown…1
• For manual operations, it is necessary to use aTakt Time increased by 15% additional (TT20 à TT35 to compensate for the fact that operators can not work at 100% of their capacity for the duration of their shift2.

This Takt Time, we will then multiplied by a OEE that we estimate vis-à-vis our knowledge, data suppliers…

### Case 2: Using Takt Time for design-redesign on an existing process

In this case, we have a history of our ability to produce and the customer need. We have quality data, the OEE… From the expected Takt Time, we will multiply it by the average OEE of equipment, allowing us to identify a value that represents a reality of production.

The X% capacity reserve is not used to make up for the delay due to a degradation of the OEE.

In other words :

• The calculation of the Takt Time with the average TRS without capacity reserve is representative of the reality of the & nbsp; daily of the line.
• The calculation of the Takt Time with the average TRS & nbsp; with capacity reserve is representative of a situation & nbsp; outstanding of the line.

## Takt Time and line flexibility

The whole issue of Takt Time is to put a figure on the level of flexibility that must have the process to stick to the customer need. With balanced tasks, we can predict different production configurations depending on the level of Takt :

• Adjust the number of machines: If the number of machines had to be doubled to meet an increase in demand, with the Takt Time, we can define from what rate of customer demand, we must use one or more machines.
• Adjust the number of operators *:  It is possible to define on a production line, the number of operators necessary according to the Takt Time.
• Adjust replenishment systems Different configurations in the number of receiving / delivery truck rotations and in the internal flow management (picking rotation of Kanban, Management Mizusumashi…).

* It will be ensured that there is no need for more than 12 operators. Indeed, beyond 12 operators, it will be complex to ensure a balance in the duration of the cycle times and we will no longer be able to dampen the variations inherent in any manual process. It will then be necessary to double the line.

## Example

We want to define different line configurations for optimal production taking into account the fact that the Takt Time will have a variability of + or – 20% and the opening time is 420 minutes.

The data are :

 Desired Flexibility -20% Nominal 20% Capacity 22 28 34 Takt Time in mn 19.1 15 12.4

### Step 1 : calculation of the number of theoretical operators

The total operating time for a single room is 54.2 minutes. If we divide this time by the time of Takt, We get the number of people necessary to make the production at Takt.

 Desired Flexibility -20% Nominal 20% Capacity 22 28 34 Takt Time in mn 19.1 15 12.4 Number of theoretical operator 2.84 3.61 4.37

### Step 2 : calculate the number of real operators

It is obvious that one will not be able to cut an operator to obtain an exact equation. The number of operators must be adjusted to the higher number.

 Desired Flexibility -20% Nominal 20% Capacity 22 28 34 Takt Time in mn 19.1 15 12.4 Number of theoretical operators 2.84 3.61 4.37 Number of real operator 3 4 5

### Step 3 : correction of the capacity

With the actual operator number, we recalculate the exact capacity. For this, we divide the total opening time by the total time of operations. If we have 4 operators, we have a total opening time of 420 * 4.

By taking our example :

 Desired Flexibility -20% Nominale 20% Capacity 22 28 34 Takt Time in mn 19.1 15 12.4 Number of theoretical operators 2.84 3.61 4.37 Number of real operator 3 4 5 Corrected capacity 23 30 38

## Go faster or slower than customer demand

Not following Takt Time is not without consequences for all actors in the value chain. 3 cases are presented :

• You’re faster than the Takt Time : We’re in the case of Overproduction Muda. The customer is happy because he has his products quickly. The company pulls its hair because it must handle overproduction (inventory management, planning control …). The supplier is dissatisfied with him because he is asked to produce strongly and orders are sent to him with a greater variability: he undergoes the Forrester Effect.
• You are slower than the Takt Time : You do not know how to deliver your customer on time and this induces strong dissatisfaction. Your provider is subject to strong variability because you are very often in an emergency mode to respond to your customer. He also undergoes Forrester Effect.
• You are at Takt Time :  At this rate, you know how to be regular and follow customer demand as closely as possible. The customer has his products on time, the stocks are at the fair and the suppliers deliver you easily.

## Source

1 – C. A Ortiz (2006) – kaizen assembly

2 – K. Erlach (2013) – Value Stream Design

T. G. Zidel (2006) – A Lean guide to transforming healthcare

P. Daneshgari, M. Wilson (2008) – Lean operations in whosale distribution

N. Rangaraj, G. Raghuram, M. M. Srinivasan (2009) – Supply Chain management for competitive advantage

J. A. C. Bokhorst, J. Slomp (2010) – Towards Takt Time controlled production units in low volume high variety environments

S.-Y. Chou, A. Trappey, J. Pokojski, S. Smith (2009) – Global perspective for competitive enterprise, economy and ecology