Kanban Production Control System

Kanban Production Control System

A kanban or "pull" production control system simple, visual signals to control the movement of materials between work centers and production of new materials to replace those who are sent downstream to the next work center. Initially, a kanban (translated as "signs" or "visible record") referred to a Japanese shop signs that communicated the types of products sold in stores through the visual image on the sign (eg, using circles of different colors to indicate a store that sells paint ). As implemented in the Toyota Production System, a kanban card attached to the container storage and transport. Identify the part number and capacity of the container, along with other information, and is used to provide easily understandable, visual signal that a particular activity is needed.

In Toyota's dual-card kanban system, there are two main types of kanban:

1. Production Kanban: signal the need to produce more parts

2. Withdrawal Kanban (also called "moving" or "vehicle" kanban):

signal the need to pull the parts from one work center and send them to the next work center.

A kanban system is called system-pull, because the kanban is used to attract the next production stage only when they are needed. Conversely, a system of MRP (material requirements planning) is a push system, in which a detailed production schedule for each part is the part that used to drive to the next production stage as scheduled.

Thus, in a pull system, material movement occurs only when the job requires more material request to be sent, whereas in a push system station which produces materials for the station organized a recipient, with the assumption that it is necessary because due to the production. Weakness push system (MRP) is that customer demand should be forecast and production period must be estimated.

Dual-card Kanban Rules:

1. No part is made unless there is a production kanban to authorize production. If there is no production kanban in the "in box" at the center of the work, the process remains idle, and workers assigned to other activities. Enforce this rule "interesting" nature of the control process.
2. There is exactly one kanban per container.
3. Container for any particular part of the standard, and they are always filled with the same (ideally, small) quantity. (Think of an egg carton, always filled with exactly one dozen eggs.)

Decisions about the number of kanban (and containers) at each stage of the process considered carefully, because this amount will be set up attached to the work-in-process inventory at that stage. For example, if 10 containers holding 12 units each are used to move materials between work centers, the maximum possible supply is 120 units, occurs only when all 10 containers full. At this point, the kanban is attached to full containers, so that no additional units will be produced (as there is no bound production kanban to authorize production). This feature dual-card kanban system allows increased productivity systematic progress. Deliberately delete one or more of kanban (and containers) from the system, a manager will also reduce the maximum level of work-in-process (buffer) stock. This reduction can be done until there is a shortage of materials. This deficiency is an indication of a problem (accident, damage to machinery, delays in production, product defects) previously hidden by excess inventory. After the problem is the solution to be observed and identified, corrective action is taken so that the system can function at a lower level of inventory buffer. This simple, systematic method of inventory reduction is a key advantage of the dual card kanban system.