After World War II, Japan was left with a disastrous economy and outdated technology. However, despite all this, their production systems later underwent a change of such magnitude that it revolutionized the economy worldwide: the introduction of new production techniques that avoid waste and waste, together with concepts related to quality, which made Japan one of the leading countries in industrial manufacturing.
Many Japanese manufacturing companies envision the assembly of a product as follows: 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 that, directly or indirectly, handles much of the manufacturing organization.
It was originally developed by TOYOTA in the 1950s as a way of managing the flow of materials on an assembly line.
Since it appeared, the Kanban process has become "A highly effective and efficient production system" which has developed an environment of industrial optimum wrapped in global competitiveness.
At present, the need to produce efficiently without causing disruptions or delays in the delivery of a given product is a factor of utmost importance for companies that want to remain active in a market like the current one, which requires 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 are currently able to meet market demands does not necessarily imply having to make large investments in expensive automation systems, or in large mobilizations and redesigns in production lines. In reality, with a proper analysis of the situations and the elements that are available, it is possible to achieve the development of an effective system that meets the needs and that is not the cause of a major investment.
The results shown by the Kanban system, when it has been implemented, have been qualified as exceptional.
ORIGIN
Until the early 1950s, many Japanese companies, to produce, made forecasts on demand and, according to the results, placed the products. On many occasions they produced more than the public demanded.
The market was not able to consume such quantities, and the clientele did not feel satisfied, since their tastes and preferences were not taken into account. There was the so-called "bullwhip effect": higher production, more stock and less service.
To deal with this problem, Japanese engineers made a study trip to the United States, there they observed how supermarkets work and discovered two events that seemed important to them:
- The supermarket sections present a limited capacity of products, made available to customers. When these products reach a minimum level, the person in charge of the section removes the products from the warehouse and replenishes the quantity that has been consumed.
The Japanese interpreted the fact that a section of products (or a container) is empty, as an order (order to replenish products). This sparked the idea of an instruction card or label (Japanese: KANBAN) in which the task to be carried out is shown; and later, the idea of a new production technique, a tense flow production, in which a product is sent to a workstation only when the order has been issued for this workstation.
Expanding on this idea; Satisfying the real demand of the consuming public would be the main objective, while minimizing delivery times, the quantity of merchandise stored and costs. Allowing the market to "pull" sales: Let the order start the production, and not the production that starts 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 developed very quickly in Japan, specifically in the TOYOTA company, and began to work well since 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 tag'.
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:
It facilitates 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, management of multiprocesses, devices for the prevention of errors (Poka Yoke), mechanisms to test error, preventive maintenance, Total Productive Maintenance (TPM), reduction of inventory levels.)
Basically Kanban is used for the following:
- Be able to start any standard operation at any time Give instructions based on current work area conditions Prevent unnecessary work from being added to orders already started and prevent unnecessary excess paperwork
KANBAN FOCUSES ON:
Production:
- Be able to start any standard operation at any time Give instructions based on current work area conditions Prevent unnecessary work from being added to orders already started and prevent unnecessary excess paperwork.
Movement of Materials:
- Elimination of overproduction - Priority in production, the most important kanban is put first than others - 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 should 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 should be good communication from the department from sales to production for those seasonal cyclical items that require a lot of production, so give plenty of advance notice.
The Kanban system must be constantly updated and continuously improved.
TYPES OF KANBAN AND THEIR USES
- Production Kanban Flag / Material Kanban Transport Kanban Urgent Kanban Emergency Kanban Supplier Kanban
Production Kanban
This type of KANBAN is used in assembly lines and other areas where the 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 treatment place according to the sequence within the process.
Bookmark Kanban / Material Kanban
This type of label is used in areas such as presses, infection molding and die casting. The marking KANBAN label is placed in certain positions in the storage areas, and by specifying the batch production, the KANBAN marking label will function in the same way as a production KANBAN.
Transport Kanban
Used when a product is moved
Urgent Kanban:
Issued in the event of a component shortage
Kanban Provider:
It is used when the distance from the plant to the supplier is considerable, so the transport time is an important term to consider.
Emergency Kanban:
When unusual circumstances occur as a result of defective components, machine breakdowns, special work or extraordinary work on weekends.
KANBAN LABEL INFORMATION
- Component part number and description Product name / number Quantity required Type of material handling required Where it should be stored when finished Reorder point Product assembly / production sequence
KANBAN IS IMPLEMENTED IN FOUR PHASES
Phase 1:
Train all staff in 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. Training with staff continues on the production line.
Phase 3:
Implementing 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 work will be carried out in their area.
Phase 4:
This phase consists of the review of the kanban system, the reorder points and the reorder levels, it is important to take into account the following recommendations for the correct operation of kanban:
- No work should be done out of sequence. If any problems are found notify the supervisor immediately.
KANBAN RULES
The production of defective products involves costs such as 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 order 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 at a time when it does not need them or in a greater quantity than it needs.
Rule 3 : Produce only the exact quantity required by the subsequent process.
This rule was made with the condition that the same process must restrict its inventory to a minimum, for this the following observations must be taken into account:
- Produce no more than the number of kanban. Produce in the sequence in which the kanban is received.
Rule 4: Balance production.
In such a way that we can produce only the necessary quantity required by subsequent processes, it is necessary for all processes to maintain the team 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
Defective work exists if the work is not standardized and rationalized, if this is not taken into account, defective parts will continue to exist.
HOW THE KANBAN RUNS
(TOYOTA Case)
- When parts needed on the assembly line are to be used first, a transport kanban is picked up and placed in a specified position.A worker takes this kanban to the pre-process to obtain processed parts, removes a production kanban from a pallet of processed parts and places it in a preset position The work-in-process kanban or production kanban removed from the pallet in the previous process, serves as an order card and work instruction that promotes the processing of semi-processed parts supplied from When this happens, the production card corresponding to the previous process to the previous one is removed from a pallet of semi-produced 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 the scheduling of production and production itself Breaking administrative barriers (BAB) are filed by Kanban Teamwork, Quality and Autonomy Circles (worker's decision to stop the line) Cleaning and Maintenance (House keeping) Provides fast and accurate information Avoid overproduction Minimizes Waste
KANBAN DISADVANTAGES
- Too long a lead time excludes the choice of the Kanban method. Well, it would have very unemployed workers. The system has no anticipation in case of very large and unpredictable fluctuations in demand. You can anticipate but not fix them. Difficult to impose this method on suppliers. Applications are limited (only for continuous or repetitive production). The KANBAN method is applicable to "mass" type productions for which the number of references is not very high, and the request is regular or with low variations. Reducing the number of Kanban without bringing radical improvements to the production system will lead to delays of 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, the enormous cultural differences.
A KANBAN SYSTEM PROMOTES IMPROVEMENTS IN TWO ASPECTS:
- The kanban makes abnormal situations patent when they are caused by machine breakdowns and product defects.A gradual reduction in the number of kanban leads to reductions in stock, which ends with the role of stock as a buffer against the instabilities of the production.
This uncovers under-trained and anomalous processes, and makes it easier to spot where improvement is required.
KANBAN FLOW
- Operator two needs material, he takes a movement card to operator one, he hangs it on a container, unhooking the production card and putting it in the card holder. This card will authorize you to produce another container of material. Operator two takes the container with the movement card attached (it is the material he needed). Operator one produces the material; puts it in a container, tying the production card to it; (who authorized him to produce it). Steps 1, 2 and 3 are repeated; As long as there is no card, it is not produced or moved. The number of cards and containers in the system serves as a regulator of the inventory in process.
KANBAN SYSTEMS
KANBAN LABELS
ELECTRONIC KANBAN WEIGHT
- The essence of the KANBAN concept is that suppliers or warehouses should only supply components to production lines when they are required, so that there are no intermediate warehouses in production areas.
KANBAN
- KANBAN processes consist of supplying 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 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 assortment of parts based on demand. This is done by defining a minimum stock for each part, and monitoring incoming and outgoing movements, and comparing whether the current stock is less than the minimum stock.These processes require a continuous supply that minimizes intermediate stock to optimize operating maneuvers.
IT Infrastructure
The KANBAN information system for 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 Direct transfer of requirements from manual to automatic Management of automatic stock levels Real-time monitoring of the flow of materials Information on materials in transit Online registration of shipments via the Internet Review of state of warehouses over the Internet.
Example of system in operation:
- The Control System was designed to control the warehouse (of company x) by controlling the minimum stock of the parts. The system performs the basic functions for managing a warehouse: parts registration, 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 assortment of parts based on demand. This is done by defining a minimum stock for each part, and monitoring incoming and outgoing 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 that of the equipment of capture. For the Database (DB) a server based on ORACLE is used, which guarantees high performance and reliability.Portable terminals with 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
- MaintenanceConsultReportRoutineConnection
Maintenance. It offers the modules to create and maintain the catalogs necessary for the operation of the system.
Query. The system offers query windows through which you have access to warehouse information, to query the status of each part, as well as to the progress of requests and kanban.
Report. Allows you to send the information of the queries to a report format. Each report is previewed and can later be directed to the printer or to a file in PDF or HTML format.
Routine. It offers the modules for the operation of the system, performs manual movements to the warehouse.
Connection. It allows you to test the state of network communication with the company. Because the requests for parts must be sent to it and the information on the advance of the containers must be received. An automatic network communication monitoring mechanism was implemented, which allows, in the event of communication failures, to deactivate shipments and activate a waiting list. This ensures that the system does not stop operating and sends all the accumulated requests in the waiting list when communication is reestablished.
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