Direct Definition: Kanban is a lean manufacturing scheduling system that uses visual signals to authorize work and control inventory. Originating from Toyota's production system, Kanban operates on a pull model, meaning new products are only manufactured or components ordered when there is a direct signal of demand from downstream operations.
Kanban (Japanese for 'signboard' or 'billboard') is a visual workflow management framework that helps manufacturing businesses manage WIP (Work in Progress), eliminate waste, and optimize capacity. By visualizing work on a Kanban board, operators and managers can optimize flow, spot bottlenecks early, and ensure peak efficiency.
The Core Principles of Kanban
Unlike push-based scheduling, which plans production based on forecasts and pushes jobs onto the shop floor, Kanban operates entirely on a pull-based philosophy. The core principles include:
- Visualize Workflow: Every task, part, or job is represented by a card and placed on a visual board. This makes the status of all active work immediately apparent to everyone.
- Limit Work in Progress (WIP): A strict cap is placed on how many cards can be in any single column at once. This prevents machines or operators from becoming overloaded.
- Manage Flow: By monitoring the movement of cards across the board, managers can identify bottlenecks and optimize the speed of the entire system.
Kanban vs T-Card Systems
While both Kanban and T-card systems use cards on a board to schedule work, they serve slightly different purposes. A traditional Kanban card acts specifically as a signal to replenish material or start a batch of a standardized product. A T-card, on the other hand, is usually custom-written for a specific job, carrying complex routing instructions and traveler details. Many modern custom job shops use T-cards to manage their scheduling, while high-volume standard product manufacturers favor Kanban.
Frequently Asked Questions
- What is the primary goal of Kanban?
- The primary goal is to minimize Work in Progress (WIP) and maximize throughput by creating a highly visual, demand-driven flow of jobs across the shop floor.
- How does a Kanban board work?
- A Kanban board lists production stages in vertical columns. Cards represent work items. As steps are finished, cards move left-to-right, signaling capacity for new work to enter the previous columns.
- Is Kanban push or pull?
- Kanban is a strict pull system. New parts or jobs are only pulled into a process step when the downstream step has completed its work and signaled capacity.