# Pull System

**URL:** https://kaizumi.com/dictionary/pull-system

**Description:** A pull system produces only when downstream processes signal demand, preventing overproduction and enabling flow.

**Category:** lean-principles

**Tags:** flow, foundational

## Definition

A pull system is a production control method where upstream processes produce only when downstream processes signal that they have consumed material and need replenishment. This contrasts with push systems where production is based on forecasts and schedules, producing regardless of actual downstream demand. Pull systems prevent overproduction—the most serious of the seven wastes—by linking production directly to consumption. Kanban cards or signals are the most common mechanism for implementing pull, though any method that triggers production based on actual demand qualifies.

## Examples

### Manufacturing

> An assembly cell uses a two-bin kanban system for components. When operators empty one bin, they place it in a return lane while drawing from the second bin. The empty bin signals the upstream process to replenish. No signal, no production—this simple pull system eliminated the chronic overproduction that previously cluttered the area.

### Healthcare

> A hospital central supply department implemented a pull system where nursing units scan items as they're used. Consumption automatically triggers replenishment, replacing the weekly push deliveries that resulted in both stockouts and expired supplies. Par levels dropped 40% while availability improved.

### Administrative

> A marketing team replaced their batch campaign approach with a pull system where sales consumption of leads triggered new campaign activation. When qualified leads dropped below threshold, campaigns launched automatically. This eliminated both lead waste (unused leads going stale) and sales complaints about lead shortages.

## Key Points

- Pull systems link production authority to actual consumption, not forecasts
- The pull signal can be physical (empty container, card) or electronic
- Pull requires controlled inventory buffers—supermarkets—between processes that can't achieve continuous flow
- Pull systems make overproduction impossible by design

## Common Misconceptions

**Pull systems eliminate all inventory.** Pull systems reduce inventory dramatically but require strategic buffers (supermarkets) between processes that can't be directly linked. The goal is controlled, visible inventory rather than zero inventory.

**Pull systems can't handle demand variation.** Pull systems handle variation by consuming from supermarket buffers, which are then replenished. Large demand spikes may require additional capacity or buffer inventory, but pull handles normal variation well.

## Play It

See pull beat push: **Flow Pro** runs the same line in batches, then one piece at a time, so you can feel the lead-time difference for yourself.

<!--GAME:flow-pro-->

## See Also

- [Kanban](/dictionary/kanban) - The most common pull signal mechanism

Source: https://kaizumi.com/dictionary/pull-system
Licence: free to quote and cite with attribution to Kaizumi.