Lean and Six Sigma are two separate methodologies, which complement each other in achieving greater value for the end customer while reducing waste. Lean Six Sigma allows minor changes in processes that can easily be implemented, and which initiate and maintain continuous improvement in processes.
I. Elimination of Waste
Millions of organisations worldwide now use Lean Six Sigma for process improvement for the elimination of waste, namely:
- Transport: Waste in moving products from one place another when it is not required to perform the processing
- Inventory: Waste of inventory when it is overstocked and is perishable
- Motion: Unnecessary movement of human resources and equipment when it can be eliminated to perform a process
- Waiting: Waste of time, human resources and equipment while employees wait for the next instruction or face obstacles to fulfill duties
- Overproduction: Production ahead of demand
- Over-processing: When unnecessary processing is done, leading to more than necessary use of resources
- Defects: Recurrent errors and their correction leading to waste of resources
Lean Six Sigma, by drastically reducing errors causing waste, leads to the enhancement of value for the end consumer while reducing cost of production. It includes the use of tools such as process discovery, measurement system analysis, process capability, inferential statistics, hypothesis testing, and process modelling.
II. Process Improvement Using DMAIC
Process improvement is achieved by the Six Sigma methodology called DMAIC, which stands for define, measure, analyse, improve, and control. These steps are implemented in a process to achieve continuous improvement.
Define: The Define phase includes selecting projects and developing a plan to eliminate elements of waste. The Define phase of Lean Six Sigma helps to identify the areas that need to be targeted to improve process productivity and waste reduction.
Measure: The Measure phase of Lean Six Sigma involves measuring the time, cost, production, and defects of a process, with the aim to eliminate waste. It involves the use of process discovery, Six Sigma statistics, system analysis, and measuring of process capability.
Analyse: The Analyse phase includes process mapping, Multi-Vari analysis, inferential statistics, and hypothesis testing to limit process risks and inefficiencies.
Improve: The Improve phase includes process modeling regression, advanced process modeling, experimental methods, fractional factorial experiments, and full factorial experiment to achieve process improvement.
Control: The Control phase involves the conducting of capability analysis, lean and defects controls, statistical process control (SPC), and Six Sigma control plans.
Lean Six Sigma has a special infrastructure of people within an organisation, which is specified by belts. There are Champions, Yellow Belt holders, Green Belt holders, Black Belt holders, White belt (awareness training) holders, etc. This signifies their level of expertise in Lean Six Sigma.
In an organisation, some employees may need to gain only specific knowledge of Lean Six Sigma to carry out their part successfully. Therefore, there are various levels of training in Lean Six Sigma that are offered.