Kanban - An Integrated JIT System

Most Japanese manufacturing companies view the making of a product as continuous - from design, manufacture, and distribution to sales and customer service. For many Japanese companies the heart of this process is the Kanban, a Japanese term for “visual record”, which directly or indirectly drives much of the manufacturing organisation. It was originally developed at Toyota in the 1950s as a way of managing material flow on the assembly line.

The Japanese Kanban process involves more than fine-tuning production and supplier scheduling systems, where inventories are minimised by supplying these when needed in production and work-in-progress is closely monitored. It also encourages; Industrial reengineering, such as a ‘module and cellular production’ system, and, Japanese human resources management, where team members are responsible for specific work elements and employees are encouraged to effectively participate in continuously improving Kanban processes within the Kaizen concept.

The Kanban

Kanban stands for Kan - card, Ban - signal. The essence of the Kanban concept is that a supplier or the warehouse should only deliver components to the production line as and when they are needed, so that there is no storage in the production area. Within this system, workstations located along production lines only produce/deliver desired components when they receive a card and an empty container, indicating that more parts will be needed in production. In case of line interruptions, each workstation will only produce enough components to fill the container and then stop.

Simple versus integrated Kanban processes

The transport Kanban contains information from where the part/component originated and its destination. When only this card is used, it is known as a simple Kanban process. In this system components are ordered and produced according to a daily schedule. This system has been described as “ordering a box when it is the only one left on line”.

The production Kanban, on the other hand, outlines to what extent and when work has to be accomplished by a specific station on the production line. Together with the transport Kanban, it is known as an integrated Kanban process. This system is often used between the corporation and its suppliers. Here, the corporation’s transport Kanban is the card which regulates the supplier’s production Kanban. The same amount of components are produced as used in production and the maximum stock level is determined by the number of cards that are in circulation.

Advantages of the Kanban process

1. A simple and understandable process

2. Provides quick and precise information

3. Low costs associated with the transfer of information

4. Provides quick response to changes

5. Limit of over-capacity in processes

6. Avoids overproduction

7. Is minimizing waste

8. Control can be maintained

9. Delegates responsibility to line workers

Industrial reengineering and Kanban

Industrial reengineerig which goes hand in hand with Kanban consists of elements such as:

1. Modular/cell production. Flow-of-products-oriented layout of processes and machines layout.

2. U-shaped production/processing lines

3. Total preventive maintenance

4. Mass production of mixed models

Modular/cell manufacturing, which is sometimes referred to as group technology involves organising machinery so that related products can be manufactured in a continuous flow. Here, products flow smoothly from start to finish, parts do not sit waiting to be worked on, and forklift trucks do not travel kilometers to move parts and materials from one part of the plant to another. Modular/cell manufacturing can be realised by U-shaped processing lines, which integrate the manufacturing process into a continuous flow and increase supply accessibility to the lines. It would be impossible to join different processes to form a U-line if processes are not integrated. In addition, Total Preventive Maintenance, which prevents machines from breaking down or malfunctioning during the production time, also contributes to the efficiency of Kanban.

Japanese Kanban process management

Kanban process indirectly focuses on the human factors of production. It involves multi-machine manning working structure, standard operations, quality control circles, suggestions systems, and continuous improvement /Kaizen. All these concepts provide for the supportive environment necessary to implement the complete Kanban process. The secret of the Kanban’s success is its requirement that each part of an organisation be totally interdependent.