Understanding Six Sigma and Stages of DMAIC

General Article

Six Sigma methodology was first introduced by Motorola in 1987 by an Engineer named Bill Smith and fully supported by Bob Galvin as CEO of Motorola at the time as a Strategy to improve and improve the process and quality control (Process Improvement and Quality Control) in his company. Six Sigma came to prominence and became Popular worldwide after Jack Welch used it as a General Electric Business Strategy (GE) in 1995. In general, Six Sigma is a methodology used to make continuous or continuous improvement and improvement processes (Continuous Improvement).

SIX SIGMA is derived from the SIX word meaning six (6) and SIGMA which is the unit of Standard Deviation which is also symbolized by the symbol σ, Six Sigma is also often symbolized to be 6σ. The higher the Sigma, the better the quality. In other words, the higher the Sigma the lower the level of disability or failure. To reduce the possibility of failure, you can apply for training in Six Sigma Green Belt Training.

Six Sigma’s strategies are:

  • Focus on Customer Satisfaction and Needs (Customer Focused)
  • Lowering the disability rate (Reduce Defect)
  • Ranging around the Target Center (Center around Target)
  • Reduce Variation

The basic concept of Six Sigma actually comes from a mix of TQM (Total Quality Management) Concept and Statistical Process Control (SPC) where the two concepts come from the thoughts of experts such as Deming, Ishikawa, Walter Shewhart and Crossby. In its development, Six Sigma, which was originally a metric, developed into a Methodology and is now a Management System.

In the Six Sigma Implementation, the target for disability or process failure is controlled in the 3.4 DPMO target (Defects per Million Opportunities), which means that in 1 Million units produced there are only 3.4 defective units. Means the company produces products with the level of customer satisfaction reached 99.9997%.

Position in Six Sigma

Position levels for insiders in Six Sigma Methodology are:

  • Champion / Sponsor (Top Management)
  • Master Black Belt
  • Black Belt
  • Green Belt
  • Team Members (Team Members)
  • Process Owner (Owner or person working on the process)

Knowledge of Statistics is a must-have for people using the Six Sigma Methodology especially in Green Belt, Black Belt and Master Black Belt positions.

To obtain the Green Belt certification, Black Belt and Master Black Belt are required special training and are tested by a testing body such as ASQ (United States) and SQI (Singapore).
Stages of DMAIC

There are 5 stages used by Six Sigma in problem solving known as DMAIC method, that is:


That is the first stage in Six Sigma to define and select problems to be solved along with Cost, benefits and impact on Customer (customer)

Tools (Tools) used in the Define stage include:

  • Function Deployment Process Map
  • SIPOC Map (Supplier Diagram, Input, Process, Output and Customer)
  • Pareto Chart
  • FMEA (Failure Mode Effect Analysis)
  • Affinity Diagram
  • Relation Diagram
  • Cause and Effect Analysis (Fishbone Chart and Cause and Effect Matrix)

Measurement is a Measurement Stage of Problems that has been defined to be completed. In this stage there is data retrieval which then Measures its Characteristics as well as the capabilities of the current process to determine what steps should be taken to make further improvements and improvements.

Tools (Tools) used in the Measurement stage are:

  • Cause and Effect Analysis (Fishbone Chart and Cause and Effect Matrix)
  • Probability Distributions
  • Basic Statistics like Mean, Median and Modus
  • Gage Reproducibility and Repeatability (GR & R)
  • Process Capability

Stage Analysis is the stage to find solutions to solve problems based on Root Cause that has been identified. In this stage, we must be able to analyze and validate Root Causes or Solutions through Hypothesis statements.

Tools (Tools) used in the Analysis stage are:

  • Hypothesis Testing (Hypothesis Testing)
  • Regression
  • Correlation Analysis
  • ANOVA (Analysis of Variance)
  • Multi-Vari Analysis
  • Contingency Table

After getting Root Problems and Solutions and validate it, the next step is to take corrective action to the problem by doing testing and experiment to be able to optimize the solution so it really useful to solve the problems we experienced.

In the Improvement Stage, the tool used is DOE or Design of Experiment consisting of:

  • Factorial Design
  • General Full Factorial Design
  • Fractional Factorial Design

The purpose of the Control stage is to establish Standardization and to control and maintain the improved and improved Process over the long term and prevent potential problems that will occur in the future or when there is a change of process, labor and change of management.

Tools (Tools) used in the Control stage are:

  • Poke Yoke (Mistake Proofing)
  • Process Control Plan
  • Process Control Chart