What is a KANBAN system?

Many Japanese manufacturing companies visualized the assembly of a product as a continuum: Design-Production-Sales Distribution-Customer Service and for many of them, the heart of this process is Kanban, a system based on the way supermarkets work. , and which, directly or indirectly, manages much of the manufacturing organization.

It was originally developed by Toyota in the 1950s as a way to manage the flow of materials on an assembly line.

Since it appeared, the Kanban process has been established as “A highly effective and efficient production system” which has developed an environment of industrial optimum wrapped in global competitiveness.

Currently, the need to produce efficiently without causing disruptions or delays in the delivery of a given product is a very important factor for companies that want to remain active in a market like the current one, which demands quick responses and quality compliance, quantity, and delivery times.

Therefore, the implementation of more efficient production systems has become a primary factor in organizations.

This implementation of production systems that currently meet market demands does not necessarily imply having to make large investments in expensive automation systems or large mobilizations and redesigns of production lines. Actually, with adequate analysis of the situations and the available elements, the development of an effective system that meets the needs and that is not the cause of a greater investment can be achieved.

The results shown by the Kanban system, when it has been implemented, have been described as exceptional.

ORIGIN

Until the beginning of the 50s, many Japanese companies, to produce, made demand forecasts and, based on the results, placed the products. On many occasions, they produced more than what was demanded by the public.

The market was not capable of consuming such quantities, and the clientele did not feel satisfied, since their tastes and preferences were not taken into account. The so-called “whip effect” was produced: greater production, more stock, and less service.

To deal with this problem, Japanese engineers took a study tour in the United States, where they observed how supermarkets work and discovered two events that seemed important to them:

• The supermarket sections have a limited capacity of products, made available to customers.
• When these products reach a minimum level, the section manager removes the products from the warehouse and replaces the amount that has been consumed.

The Japanese interpreted the fact that a product section (or a container) is empty, as an order (product replenishment order). This awakened in them the idea of ​​an instruction card or label (in Japanese: KANBAN) in which the task to be carried out is shown; and later, the idea of ​​a new production technique, a tight flow production, in which a product is sent to a job only when the order has been issued for this job.

Expanding on this idea; satisfying the real demand of the consuming public would be the main objective while minimizing delivery times, the amount of merchandise stored, and costs. Allow the market to “pull” sales: Let the order start production, and not production start looking for a buyer. The purpose is to be able to supply the customer with his planned order, on the scheduled day, and at a minimum cost.

Since then, this technique has developed very quickly in Japan, specifically in the TOYOTA company, and began to work well in 1958. The generalization of this idea to the production system would become the Kanban system.

Is defined as:

“A highly effective and efficient production system.”

KANBAN means in Japanese:

‘instruction label’.

Its main function is to be a work order, that is, an automatic steering device that gives us information about what is going to be produced, in what quantity, by what means, and how to transport it.

KANBAN FUNCTIONS

There are two main functions of Kanban:

• Production control
• Process improvement

Production control:

It is the integration of the different processes and the development of a Just in Time system, in which the materials will arrive in the time and quantity required in the different stages of the factory and if possible including the suppliers.

Process Improvement:

Facilitates the improvement in the different activities of the company through the use of Kanban, this is done through engineering techniques (elimination of waste, organization of the work area, reduction of model changes, use of machinery vs. use based on demand, multiprocess management, error prevention devices (Poka Yoke), error-proofing mechanisms, preventive maintenance, Total Productive Maintenance (TPM), reduction of inventory levels.)

Kanban is used for the following:

• Being able to start any standard operation at any time
• Give instructions based on current conditions in the work area
• Prevent unnecessary work from being added to orders already started and prevent unnecessary excess paperwork

KANBAN FOCUSES ON:

Production:

1. Being able to start any standard operation at any time.
2. Give instructions based on current conditions in the work area.
3. Prevent unnecessary work from being added to orders already started and prevent unnecessary excess paperwork.

Movement of Materials:

1. Elimination of overproduction.
2. Priority in production, the kanban with the most importance is put first then the others.
3. Material control is facilitated.

Considerations before implementing Kanban

• Determine a production scheduling system for final assemblies to develop a mixed production and labeling system.
• A Kanban route must be established that reflects the flow of materials, this implies designating places so that there is no confusion in the handling of materials, it must be made obvious when the material is out of place.
• The use of Kanban is linked to small-batch production systems.
• It should be taken into account that those items of special value should be treated differently.
• There must be good communication from the sales department to production for those seasonal cyclical items that require a lot of production, so that notice is given well in advance.

The Kanban system must be constantly updated and continuously improved.

KANBAN TYPES AND THEIR USES

• Production Kanban
• Flag Kanban/Material Kanban
• Transportation Kanban
• urgent kanban
• Emergency Kanban
• Supplier Kanban

Production Kanban

This type of KANBAN is used in assembly lines and other areas where set-up time is close to zero. When the labels cannot be attached to the material, for example, if the material is being treated under heat, they should be hung near the place of treatment according to the sequence within the process.

Flag Kanban/Material Kanban

These types of labels are used in areas such as presses, injection molding, and stamping (die casting). The KANBAN flag label is placed in certain positions in the storage areas, and by specifying the production of the batch, the KANBAN flag label will work in the same way as a production KANBAN.

Transportation Kanban

Used when moving a product

Urgent Kanban:

Issued in case of shortage of a component

Supplier Kanban:

It is used when the distance from the plant to the supplier is considerable, so the transport time is an important term to take into account.

Emergency Kanban:

When due to defective components, machine breakdowns, special jobs, or extraordinary work on weekends, unusual circumstances occur.

KANBAN TAG INFORMATION

• Part number and description
• Product Name / Number
• Required quantity
• Type of material handling required
• Where should it be stored when finished?
• reorder point
• Product assembly/production sequence

KANBAN IS IMPLEMENTED IN FOUR PHASES

Phase 1:

Train all staff on the principles of kanban, and the benefits of using it.

Phase 2:

Implement kanban on those components with the most problems to facilitate their manufacture and to highlight hidden problems. Staff training continues on the production line.

Phase 3:

Implement kanban in the rest of the components, this should not be a problem since for this the operators have already seen the advantages of kanban, all the opinions of the operators must be taken into account since they are the ones who know the system best. It is important to inform them when you will be working in your area.

Phase 4:

This phase consists of the review of the kanban system, reorder points and reorder levels, it is important to take into account the following recommendations for the correct operation of kanban:

1. No work should be done out of sequence.
2. If any problem is found, notify the supervisor immediately.

KANBAN RULES

Rule 1: Defective products should not be sent to subsequent processes.

The production of defective products implies costs such as the investment in materials, equipment, and labor that will not be able to be sold. This is the biggest waste of all. If a defect is found, measures must be taken first of all to prevent it from happening again.

Rule 2: Subsequent processes will require only what is necessary.

This means that the subsequent process will request the material it needs from the previous process, in the necessary quantity and at the right time. A loss is created if the previous process supplies parts and materials to the subsequent process when it does not need them or in a greater quantity than it needs.

Rule 3: Produce only the exact amount required by the subsequent process.

This rule was made with the condition that the process itself must restrict its inventory to a minimum, for this the following observations must be taken into account:

• Do not produce more than the kanban number.
• Produce in the sequence in which the kanban is received.

Rule 4: Balance production.

So that we can produce only the necessary quantity required by subsequent processes, it becomes necessary for all processes to maintain equipment and workers in such a way that they can produce materials at the necessary time and in the necessary quantity.

Rule 5: Kanban is a means to avoid speculation.

So for the workers, KANBAN becomes their source of information for production and transportation, and since the workers will depend on KANBAN to carry out their work, the balance of the production system becomes of great importance.

Rule 6: Stabilize and streamline the process

The defective work exists if the work is not standardized and rationalized, if this is not taken into account, there will continue to be defective parts.

HOW THE KANBAN CIRCULATES
(TOYOTA Case)

1. When the parts needed on the assembly line are to be used first, a transportation kanban is collected and placed in a specified position.
2. A worker takes this kanban to the pre-process for getting processed parts, removes a production kanban from a pallet of processed parts, and places it in a preset position.
3. The work-in-process kanban or production kanban removed from the pallet in the upstream process serves as an order card and work instruction that promotes the processing of semi-processed parts supplied from the upstream process.
4. When this occurs, the production card corresponding to the previous process is removed from a pallet of semi-manufactured parts and replaced by a transport kanban.

ADVANTAGES OF USING JIT AND KANBAN SYSTEMS

• Reduction in inventory levels.
• Reduction in WIP (Work in Process).
• Reduction of downtime.
• Flexibility in production scheduling and production itself.
• The breaking of administrative barriers (BAB) is archived by Kanban
• Teamwork, Quality Circles, and Autonomy (Decision of the worker to stop the line)
• Cleaning and Maintenance (Housekeeping)
• Provides fast and accurate information
• Avoid overproduction
• Minimize Waste

DISADVANTAGES OF KANBAN

• Too long a lead time precludes the choice of the Kanban method. Well, the workers would be very unemployed.
• The system does not have any anticipation in case of very large and unpredictable fluctuations in demand. You can anticipate them but not fix them.
• It is difficult to impose this method on providers.
• Applications are limited (only for continuous or repetitive production). The KANBAN method applies to “mass” type productions for which the number of references is not very high, and the request is regular or with small variations.
• Reducing the number of Kanbans without making radical improvements to the production system will lead to delays in delivery and waiting between operations and, consequently, significant losses.
• It has not been successful or has reached optimal performance when it has been implemented in Western organizations. One of the main causes of this is the enormous cultural differences.

A KANBAN SYSTEM PROMOTES IMPROVEMENTS IN TWO ASPECTS:

1. The kanban makes abnormal situations clear when they are caused by machine breakdowns and product defects.
2. A gradual reduction in the number of kanbans leads to reductions in stock, which ends the role of stock as a buffer against production instabilities.

This exposes under-capacity and failing processes and simplifies the discovery of areas that require improvement.

KANBAN FLOW

1. Operator Two needs material, he takes a movement card to Operator One, hangs it on a container, takes down the production card, and puts it in the cardholder. This card will authorize you to produce another container of material.
2. Operator two takes the container with the movement card attached to it (it’s the material he needed).
3. Operator one produces the material; he puts it in a container, tying the production card to it; (who authorized him to produce it).
4. Steps 1, 2, and 3 are repeated; as long as there is no card, it is not produced or moved.
5. The number of cards and containers in the system serves as a regulator of the inventory in the process.

KANBAN SYSTEMS

KANBAN LABELS

ELECTRONIC KANBAN PROCESS

• The essence of the KANBAN concept is that suppliers or warehouses should only provide the components to the production lines when they are required, in such a way that there are no intermediate warehouses in the production areas.

kanban

• KANBAN processes consist of the supply of materials to the assembly lines in the form of containers or boxes of the same piece.
• The Electronic Kanban System was designed to control the supply of containers to the assembly lines, by controlling the minimum stock of the parts.
• The system performs the basic functions for managing a warehouse: registration of parts, entry, exit, etc. And it provides information and reports on the status of the warehouse (stocks) and operations or movements carried out.
• The System operates under the scheme of automatic supply of parts based on demand. This is done by defining a minimum stock for each part, and monitoring inbound and outbound movements, and comparing whether the current stock is less than the minimum stock.
• These processes require a continuous supply that minimizes the intermediate stock to optimize the operation maneuvers.

IT Infrastructure

The information system for KANBAN processes offers all the facilities to achieve an efficient and reliable operation in the KANBAN supply, such as:

• Status of intermediate warehouses in logistics areas.
• The direct transfer of manual to automatic requirements.
• Management of automatic stock levels.
• Real-time monitoring of the flow of materials.
• Information on materials in transit.
• Online registration of shipments through the Internet.
• Review of warehouse status through the Internet.

 Example of the system in operation:

• The Control System was designed to control the warehouse (company x ) by controlling the minimum stock of the parts.
• The system performs the basic functions for managing a warehouse: registration of parts, entry, exit, etc. And it provides information and reports on the status of the warehouse (stocks) and operations or movements carried out.
• The System operates under the scheme of automatic supply of parts based on demand. This is done by defining a minimum stock for each part, and monitoring inbound and outbound movements, and comparing whether the current stock is less than the minimum stock.
• The system uses current technology both in its programming part and in the capture equipment part. For the Database (DB) an ORACLE-based server is used, which guarantees high performance and reliability.
• Portable terminals with a radio frequency (RF) link are used to capture data from the warehouse. These terminals perform direct interaction with the database, thereby increasing productivity and better performance.

The system menu handles five options:

The system menu handles five options

• Maintenance
• Consultation
• Report
• Routine
• Connection

Maintenance. It offers the modules to create and maintain the catalogs necessary for the operation of the system.

Consultation. The system offers query windows through which you have access to warehouse information, to query the status of each part, as well as the progress of requests and kanban.

Report. It allows sending the query information to a report format. Each report presents a preview and can later be directed to the printer or a file in PDF or HTML format.

Routine. It offers modules for the operation of the system and performs manual movements to the warehouse.

Connection. Allows you to test the status of network communication with the company. Because the requests for parts must be sent to it and the information on the progress of the containers must be received. An automatic network communication monitoring mechanism was implemented, which allows, in the event of communication failures, deactivating shipments, and activating a waiting list. With this, it is achieved that the system does not stop its operation and sends all the applications accumulated in the waiting list when the communication is re-established.