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What is the difference between lean and six sigma - Part 2

By now we should have a better understanding of six  sigma.  More detail about six sigma can be found in my previous posting, http://www.360qualitymanagement.com/2017/09/continuous-quality-improvement-program.html.  

In this section I shall give an overview of lean.


Lean is a culture  which focuses on creating “value” to the customer through a culture of continuous improvement and focus on reduction/elimination of waste.  Value in this context means 

  1. customer is willing to pay for activity which involve in transforming the raw material to final product.
  2. Activity must transform the part (inspection is not counted as there is no transformation work involve,  there is no difference in physical aspect of the part before and after inspection)
  3. Do it right the first time


Waste in the definition of lean refer to the 7 waste as per below.  Waste need to be identified  through value stream mapping. Value stream map is  a depiction  of entire production(material and information) flow  which include non value and value added activities to create a product.  Value stream mapping is an exercise to create a value stream map by charting all current activities required to create a product and include some relevant information such as cycle time, defect rate etc.  Once the current value stream map is completed,  the team will be able to see all activities and identify waste follow by envision the future state.  In order to achieve future state map,  there must improvement plan (known as kaizen) to address the waste either by reduction and elimination to simplify the process.  Lean tools which can be used  to manage waste such as 5S, standard work, pull system, visual management,  poke-yoke, Kanban etc.
7 Waste In a value stream

An Example of a value stream map

Six sigma is a  problem solving approach originated from American organization which focus on sample data collection which represent population with lots of statistical analysis of a tactical problem.  Lean is a management culture was practiced  by Japanese which focus on observing all the process for product creation in the value stream to identify waste. Six sigma focus on data, lean focus on “learning to see” (refer to book of the same title by John Shook et. al). 

In my opinion,  six sigma can be part of lean. Six sigma can be used as a tool in  kaizen as it is the best tool in variation reduction related to product defect,  thus reduce waste related to defect.  However lean can NEVER part of six sigma, at most lean tools can be used  as an approach in improvement action plan during the improve phase of a six sigma project. 
Some of the common lean tools, six sigma could be one of the lean tools to address defect waste

Due to lean tools is simple to use as lean is about simplification, many companies had adopted lean tools such as 5S, poke yoke etc. globally.  Hard core six sigma organization had also deploy lean tools and thus this could be the beginning of lean six sigma term.  Many companies end in confusion when they try to embrace six sigma as a culture using the six sigma approach to solve every problem!!!!
The table show the comparison between  lean and six sigma


Six sigma
Lean
Purpose
To reduce a critical to quality metric data variation
Bring value to customer through elimination of waste by striving for continuous improvement
What it is
Tool
Culture
Approach
Phase by phase  with data collection
Overall value stream mapping through gemba walk of observing the activity
Application area
Point to point improvement
Throughout supply chain
Expertise requirement
Statistic
People  management

A company does not qualify as a lean culture company by just adopting a few lean tools. Lean culture is about management leadership creating a work place which respect its worker who bring value to product by eliminating waste through continuous improvement.   A real lean company will not hire excessive worker as there is not much waste to be managed and then later on fire when the worker is not needed.  Lean culture company is able to do more with less to achieve consistent good quality product with minimal waste.
Both Lean and six sigma is NOT magic which enable wealth creation of a corporation.  In order to practice both lean and six sigma successfully, an organization would require a skill workforce with discipline.  Unfortunately discipline had become rare commodity in today world which attribute to why many company failed eventually.

Refer to this video for more details



Zero defect a Myth or a reality - Organization accountability


In a normal situation, consumers only buy one product and thus the product must be functioning for its intended usage and specification.  This means a product or service supplier to end consumer only get one chance to show their product is of good quality.  Therefore, all products sold to the consumer market should achieve zero-defect or a very low defect rate such as six sigma quality which is equal to 3.4 defects in one million parts.  

Product with zero defects is a dream of every organization.  The next big question would be what it takes to achieve zero defects.  In the modern world, the end product which reaches the end-user or consumer goes through a very long supply chain, from mother nature raw material such metal, silicon wafer, petrol chemical by-product to form into piece part assemble into sub-assembly and then join together to become final assembly. 



All the touchpoint throughout the supply chain will increase error opportunity which could induce defect in a product.  Refer to this link on the concept of the supply chain. 

The most important condition to strive for the perfection of zero defect is an overall product design with design for manufacturability, serviceability, consumer etc in mind.  Quality awareness must start right from the design of the product. 

Unfortunately, most of the design only focuses on the functionality of the product which resulted in poor manufacturability, the limited supply chain of material and complicated product which is not user friendly.
Many organizations did not realize that zero-defect must be designed in from raw material to piece part to sub-assembly to final assembly.  The irony is that those organizations thought manufacturing process can compensate for the poor design and limited material supply base. 

Very often a company tend to take short cut design process of a product to save on design cost and time to market which uses substandard material.  This had created a ripple effect where company have to live with poor design, spend a huge amount of money to hire resources downstream to manage complicated manufacturing process for the infinite duration of time. 

I will share more about design for manufacturability concept which leads to the zero-defect product in the next article. Please do follow this website by clicking on "Follow" on the top right sidebar.   I have created a youtube video to explain more on this topic.






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