Kanban and Pull System: A Practical Guide to Lean Implementation

Optimize Workflow with Kanban and Pull System

In the world of manufacturing lean, Kanban and the Pull System emerge as powerful tools for optimizing workflow, reducing waste, and improving operational efficiency. This guide explores how to effectively implement these methods in your organization, ensuring a smooth transition towards leaner, more responsive management.

The Transition to Pull Logic: Kanban vs. MRP

The difference lies in the production fundamentals and in Flow control. In traditional systems like the’Material Requirements Planning, the logic is Push (Push): The system calculates requirements based on forecasts and establishes a backward schedule. This approach leads to the formation of stockpiles, where products wait to be consumed, creating the risk of waste and obsolescence.

On the contrary, the Kanban adheres to logic Pull (a shot), fully identifying with the philosophy Just-in-timeit only produces what is needed, when it is needed, in the quantity that is needed. The tag Kanban same serves as a production order, but it is issued only at the time of consumption downstream material.

This change also revolutionizes the production controlwhereas MRP requires complex forward scheduling, Kanban drastically simplifies the process. It controls production by only scheduling the Final phase of the line and reducing the time horizons of the programs, shifting, for example, from weekly to daily programs and beyond. In this way, it becomes much simpler and faster to vary production plans in response to real market changes or errors in initial forecasts.

Kanban: Visual Management and Limiting Work in Progress

The Kanban it is a method of visual management originated in Japan and helps manage the flow of materials and work in progress. Based on visual cues (cards or tags), the system operates on two fundamental levels:

• Information and order: the price tag Kanban acts as Work order, specifying clearly what, when, and how much to produce or transport.
• Flow control: helps manage production by limiting work in progress (WIP), making the workflow continuous and immediately visible. The WIP limit is crucial for creating the Pull System and prevent overproduction.

The three main types of Kanban

There are three main types for managing different aspects of material flow:

• Production Kanban
• Kanban replenishment
• supplier kanban

The 6 fundamental rules for effective Kanban

Kanban's effectiveness stems from strict adherence to these six operating rules:

• Do not deliver defective material to the downstream process.
• the withdrawal is carried out by the customer (downstream process).
• produce only the amount withdrawn.
• The production program must be leveled (uniform).
• Kanban is used for optimization.
• stabilize and rationalize the process.

When to apply Kanban

The implementation of Kanban and of Pull System It extends beyond (manufacturing) production, finding applications in sectors such as software development, project management, and customer service. This ensures flexibility and accessibility, providing optimal control over processes and improving day-to-day interactions with available resources.

Adopting these methods not only enhances the ability to adapt to market needs, but also provides a robust system for the continuous improvement (Kaizen).

Kanban is the appropriate tool when you want to transition from a forecast-driven production system to one driven by actual demand. It is used when:

• Work-in-progress inventory is high and difficult to control

• Overproduction is one of the main types of waste identified in value stream mapping

• The process has stages with different cycle times, which generate backlogs of materials.

• The goal is to synchronize internal production with the customer's actual consumption without resorting to complex scheduling systems.

Kanban is not suitable for all contexts: it works best with products that have relatively stable and repetitive demand. For highly customized products or those with highly variable demand, it requires careful design of the sizing parameters.

How to size a Kanban system

Proper sizing is what distinguishes a system that works from one that results in stockouts or excess inventory. The key parameters are:

• Average question during the reference period

• Replenishment lead time — the time required to restore the data once the signal is received

• Variability in Demand — the safety factor that protects against fluctuations

• Container size — the minimum volume of cargo handling that is economically and operationally sustainable

The basic formula for the number of Kanban cards is: (Lead time + Safety stock) / Container size. The system must be periodically recalibrated as demand and replenishment lead time change.

The Most Common Mistakes in Implementing Kanban

• Implement it without stabilizing the process — Kanban works for processes with controlled variability. If cycle times are unstable, failures are frequent, or quality is inconsistent, the Kanban signal cannot reliably regulate the flow.

• Size the system with theoretical data instead of real data — Using theoretical cycle times or stated lead times instead of measured ones leads to incorrect inventory planning, which results in stockouts or excess inventory.

• Do not recalculate parameters over time — A Kanban system designed for a demand of 100 units per day does not work when demand changes to 150 or drops to 60. The system must be monitored and recalibrated regularly.

• Introduce it into a system that is still Push — Kanban is a pull system: it cannot coexist for long with a centralized scheduling approach that continues to push material into the process regardless of actual consumption.

• Consider it a manufacturing-only tool — Kanban is also effectively applied to administrative processes, procurement, project management, and services. The logic is the same: produce or supply only when there is actual demand.

Kanban in the Lean World Class® Method

In the Lean World Class® method, Kanban is the tool that operationalizes the Pull principle in daily flow management. Its implementation is always preceded by value stream mapping and process stabilization, ensuring that the Pull system is built on solid foundations and produces lasting results.

Want to see how Kanban is applied in a real project? Discover the method Lean World Class® developed by Bonfiglioli Consulting