In the process of getting the hang of Lean management, you will learn that establishing a pull system of work is among the most important prerequisites to achieving optimal process efficiency.
Pull is a powerful concept that will allow you to take control of your workflow and deliver value to your customers precisely when it counts. As we’ve already covered what a pull system is, we’ll show you how to establish and maintain one with the Kanban method's help.
Why Use Kanban to Establish Pull Systems?
Kanban is the original and by far the most popular method for applying a pull system. It was part of the Toyota Production System that brought attention to the lean way of managing work.What makes Kanban so suitable for running a pull system is its simplicity. The method is built on a short set of principles and values that are easy to teach and do not require a colossal change from the very beginning.
Many teams fail to understand that Kanban is more than just a set of boards and cards. If you want to implement a Kanban pull system successfully, your team needs to stick with the six core practices of the method:
Visualize the workflow
Make process policies explicit
Maintain open feedback loops
How to Implement a Pull System with Kanban?
There are 3 key steps you need to follow when you are preparing to apply a Kanban pull system to your process. They will most likely determine whether your implementation will be successful or not.
Map Your Workflow
Visualizing your workflow is the foundation of Kanban and a vital part of keeping your pull system efficient. You need to be as precise as possible when preparing your Kanban board.
The default board setup consists of 3 sections representing your workflow states (requested, in progress, done). You need to carefully consider every part of your process and determine the steps of each stage.
Typically, you would like to break down the In progress stage into as many steps as possible to have a comprehensive view of your workflow and instantly spot any problems.
After your boards are all set up and ready for action, you should stop pushing new work in your process and start pulling only when there is a demand for it.
This will allow you to reduce your assignments' cycle time by focusing on work that will bring value to your customers just at the right time. As a result, you will be able to increase your process's efficiency and lower inventory costs.
Limit Work in Progress
Even if you pull new work when there is a demand for it, your process may get clogged and stay inefficient. To be lean and make your Kanban pull system count, you need to control the amount of work that gets in and out of your workflow.For this purpose, you need to place limits on the work in progress (WIP) and make sure that your team complies with them. You may set up such limits per person, work stage/column, or on a global scale for the whole board. You can also restrict the utilization of given resources (ex. machines) in your process by using token-based WIP limits.
Your goal here is to reduce the lead time of your work items and make your flow as smooth as possible. For this to happen, you need to help your team focus. Encourage them to work on as few tasks as possible simultaneously to avoid switching context.
How to Manage a Kanban Pull System?
After you’ve got your Kanban pull system up and running, you need to address another key aspect of Lean management – continuous improvement. As a manager, you should keep a close look at your process and make adjustments whenever needed. Here’s how you can approach this in a few steps.
Break Down Work
Keeping your flow smooth and running requires that you take good care of the cycle time of all cards that pass through your Kanban boards.
As you would want to reduce cycle times as much as possible, we advise you to break down your work into tasks that require no more than a few days to move from requested to done.
This will allow your team to pull work more often from one stage to another and keep all parts of your process running. As a result, you will not only reduce the cycle times of your work assignments but increase the throughput of your pull system.
Apply Pull Signals
Pull signals will allow your team to understand when a task is ready to be moved on to the next stage of your workflow. In Kanban, the most simple way to apply such signals is to dedicate a few columns for the purpose.
Simple examples of that are the “review” columns that you should place after every specific activity that needs to be evaluated.This will allow you to signal that a work item is ready to move on to the next stage and help you increase the built-in quality as you’ll be able to ensure that there are no mistakes in the production process.
For example, in software development, you can break down your production process into 3 dedicated stages: tech design, coding, and testing. By adding a review step after every stage, you can ensure that all aspects are communicated and there are no issues with the feature’s deployment. Placing a column such as "Ready for review" will create a pull signal, indicating that the person responsible for work evaluation needs to take action as soon as possible.
There are many other examples of applying a pull system in the knowledge work processes of different industries. Let’s take architecture for instance.
Besides the “committed stage” where you plan the work to execute next, you can break down your workflow into a: “Working stage” where you design drawings and a “Review stage” where different subject matter experts give their feedback. It's then important to study your process, apply WIP limits and pull signals such as buffer columns (ex. Ready for Review) in order to signal that a work item is ready to move forward and so you can eventually smooth out your workflow.
Bottlenecks are an inevitable part of every process, no matter how advanced it is. They are a typical reason for failing to establish a smooth workflow. The issue with bottlenecks derives from the imbalance in the capacity of the distinct stages of your workflow.
For example, if you’ve got 10 developers working on your new product release and only one person responsible for the code review stage, it will be no surprise that this will likely be your bottleneck stage.
Often the real problem with managing bottlenecks is that they are not visible. However, if you’ve mapped your workflow precisely on a Kanban board, they should be recognizable at first sight.