• Kanban is a simple‐to‐operate visual control signal/tool to facilitate a “pull system,” that offers the opportunity to delegate routine material transactions on the shop floor.
Kanban is used to link processes/operations that Are separated by distance
Benefits of Kanban
• Applies to parts, assemblies and information production so they can be paced to customer demand
• Minimizes raw material inventories, work inprocess and finished goods
• Maintains a balance between work centers through consumer/supplier communication
• Spotlights abnormal situations when processes are halted.
Shapes of Inventory
– Connect process
– Establish a location (“Store”) to pull from
– Hold a variety of different parts (e.g mix changes)
– Used to absorb sudden changes in customer demands
• Safety stock:
– Used as a precaution for equipment breakdown
• Standard in process stock:
– Store used to accommodate “Standard work” e.g., repeatable work or tool change work
Types of Kanban
• Kanban Card: Cards are exchanged between the consumer and producer of products or services. Information on the cards may include an indication of how many parts are needed, part number, consumer and producer location, and containers. Kanban cards are often colored, and the colors give an indication of the area and priority of the Kanban and its contents.
• Toyota Two‐card System: This is a two‐card (two‐bin) Kanban system. Here the move cards allow the movement of a standard container of parts from one work center to another. The production cards allow the production of a standard container of parts to replace the parts removed by the previous move card.
• Verbal Control: If possible, the consumer signals that more material is needed by telling the producer. This communication may happen by phone, email, fax or simply by shouting.
• Kanban Containers: When the empty container returns to the supplying operation, this is a signal for the need to produce more items. The container must be properly marked (number or color) to show which material it needs or the priority.
• The consuming process should withdraw the needed products/units from the supplying process at the right point in time using a Kanban signal.
• Kanban cards, if used, always accompany containers from the supplier until removed from the Kanban staging area, thus ensuring visual control.
• Each container must have a Kanban card, indicating the part number and description, consumer and producer location, and quantity
• The parts should always be pulled by the succeeding process (consumer).
• No parts are produced without a Kanban signal.
• No defective parts may be sent to the consuming process.
• The producer may only produce the quantities withdrawn by the consuming process.
• Step 1: (Designed daily production requirement * Replenishment rate ) Available time = Kanban quantities
• Step 2: Kanban quantities / Lot size = # of cards
Note: Lot size > 1 may be required due to weight, size
A Pull system for multiple processes is comprised of a series of closed loop information loops, all integrated together in a chain of “customer‐suppliers”
CONWIP – An Alternative to Kanban
• Release new work as work is completed
FIFO – First in First Out
Option to Control WIP in high variety manufacturing