Six Sigma

In this lesson, you’re expected to learn about:
– the basics of the six sigma metric
– the meaning of different sigma levels
– tool and techniques used in different models

What is Six Sigma?

Six-Sigma is a statistical concept to describe accuracy and quality levels in a process, product, or service, which can lead to a competitive advantage in the marketplace.

The word sigma is associated with a statistical term, standard deviation, which is the distance from the mean (average).

Six-Sigma is a strategy, discipline, system, program, and tool to achieve quality improvement continuously, to solve problems, to improve functions and features of a product or service, to reduce cost and time, and to increase customer satisfaction.

Meaning of Different Sigma Levels

• Three-Sigma means 66,800 defects in a million parts produced.
• Four-Sigma means 6,210 defects in a million parts produced.
• Five-Sigma means 230 defects in a million parts produced.
• Six-Sigma means 3.4 defects in a million parts produced.

The goal of reaching Six-Sigma from Three-Sigma is a challenging one as it is a non-linear process to reach the goal.

Six-Sigma follows an improvement model called DMAIC, which stands for define, measure, analyze, improve, and control stage.

D defines the project’s purpose, scope, and outputs, M measures the process and collects data, A analyzes the data to ensure
repeatability and reproducibility, I improves or redesigns the existing process, and C controls the new or modified process for increased performance.

Implementing a Six-Sigma program requires a strong commitment from employees and management in terms of time, training, and expertise.

Six-Sigma redefines quality performance as defects per million opportunities (dpmo) and is calculated as:

dpmo = (Defects per Unit) x 1,000,000 / Opportunities for Error

where Defects per Unit = Number of Defects Discovered / Number of Units Produced
[Optional] What is Six Sigma?
Tools and Techniques Used in DMAIC Model

Examples of tools and techniques used in the Define stage include brainstorming, cause-and-effect diagram, and process mapping.

Examples of tools and techniques used in the Measure stage include cause-and-effect diagram and process mapping.

Examples of tools and techniques used in the Analyze stage include regression and correlation analysis and process mapping.

Examples of tools and techniques used in the Improve stage include brainstorming, simulation, design of experiments, and process mapping.

Examples of tools and techniques used in the Control stage include mistake-proofing (Poka-yoke), statistical process control, and control charts.

Design for Six Sigma

Design for Six-Sigma (DFSS) is a proactive approach in preventing problems from occurring in the first place and/or in resolving problems after they occur. The focus is on functional and quality improvement at the early design stage.

An approach to DFSS is established in terms of DCOV model, which stands for define, characterize, optimize, and verify.

Tools and Techniques Used in DCOV Model

Examples of tools and techniques used in the Define stage include Kano model, quality function deployment (QFD), and regression and conjoint analysis.

Examples of tools and techniques used in the Characterize stage include design of experiments and TRIZ (a problem-solving tool).

Examples of tools and techniques used in the Optimize stage include design of experiments, simulation, mistake-proofing, and control charts.

Examples of tools and techniques used in the Verify stage include design walkthroughs and reviews and product tests.

DFSS is similar to other design concepts such as design for manufacturability (e.g., lean production and standard parts), design for low cost (e.g., overhead costs, supply-chain costs, and quality costs), design for faster production (e.g., flexible manufacturing and concurrent engineering), design for faster marketing (e.g., time-to-market, quality function deployment, and voice of the customer), design for safety and ergonomics (e.g., safe products and human factors), design for a better environment(e.g., pollution control and recycling), and design for serviceability(e.g., post-sales activities such as ease of repair and maintenance).
Six-Sigma Players

Several Six-Sigma players exist in the planning and implementation of the Six-Sigma program in an organization, including White Belts (at the bottom), Green Belts, Yellow Belts, Black Belts, Master Black Belts, Project Champions, and Senior Champions (at the top of the Six-Sigma hierarchy).

All of these players assume defined roles and responsibilities and need specific training with varying lengths to make the Six-Sigma program a success.

White Belts are hourly employees needing basic training in Six-Sigma goals, tools, and techniques to help Green Belts and Black Belts on their projects.

Green Belts are salaried employees who have a dual responsibility in implementing Six-Sigma in their function and carrying out their regular duties in that function. They gather and analyze data in support of a Black Belt project and receive a simplified version of Black Belt training.

Yellow Belts are seasoned salaried employees who are familiar with quality improvement processes.

Black Belts are salaried employees who have a full-time responsibility in implementing Six-Sigma projects. They require hard skills and receive extensive training in statistics and problem-solving and decision-making tools and techniques, as they train Green Belts. Black Belts are very important to Six-Sigma’s success.

Master Black Belts are also salaried employees who have a full-time responsibility in implementing Six-Sigma projects. They require soft skills, need some knowledge in statistics, and need more knowledge in problem-solving and decision-making tools and techniques, as they train Black Belts and Green Belts.

Senior Champions are sponsors and executives in a specific business function and manage several Project Champions at the business unit level, who in turn manage specific projects.

Senior Champions develop plans, set priorities, allocate resources, and organize projects. Project Champions deploy plans, manage projects that cut across the business functions, and provide managerial and technical guidance to Master Black Belts and Black Belts.

Jim Rohn Sứ mệnh khởi nghiệp