Principles of Lean Improvement - Creating Flow

Lean Nation,

Following up on the previous blog in which I discussed the five principles of lean improvement,  this post will cover the first principle; creating flow.  Like a river flows from its tributaries toward a lake or sea,  so should work "flow".

Many practitioners new to lean, believe that the principle of flow involves lining up all the work activities one after another.  This is incorrect.  First wasteful activity should be eliminated. and the remaining activities should be lined up for continuous flow.  In meeting the spirit of  flow, the desire is to have only value added activities flow one after another.

But creating flow has other attributes as well.  In addition to lining up the value added activities one after another, other conditions are also desired.  First, the goal is to have no waiting between steps.  Like the river, we desire work to flow continuously.  Secondly,  having work flow continuously, but having a large queue in front of the flowing work would also be wasteful.  The desire of a system with flow is to have the work flow at the rate of the customer demand.  In lean circles this is known as takt time.  This is necessary in order to service all of the customers with minimal or even no waiting.    The third attribute of flow is to have the work "recipe" be consistent and repeatable.  It does little good to have flowing work with no inventory between steps, paced to the customer demand, when the end product is not to the customer specification. 

Summarizing the spirit of flow, the system should be designed so that:

1. value added tasks are lined up one right after another
2. no inventory or waiting exists between the steps
3. the work is paced to rate of the customer demand
4. work is performed consistently with a repeatable outcome

The benefits of flow are many.  These include the following at a minimum:

• The timeline for the work to be completed shrinks
• Quality improves since immediate feedback from one step the the next is possible
• Inventory shrinks for two reasons. First, there is no work piling up between steps.  Secondly, work does not pile up at the front of the queue since the work is paced to rate of customer demand.
• Waste is readily visible as a disruption in flow stops the work making the waste visible for correction.

When undertaking lean improvement, it is recommended to begin with flow.  I recommend you always begin with flow.  Flow enables the elimination of great amounts of waste and allows the other wastes to be readily visible so they can eliminated later. 

The next post will focus on pull.

Lean Blessings,

Ron
Ron Bercaw
President, Breakthrough Horizons
www.breakthroughhorizons.com
Shingo Award Winning Author