Six Sigma is a business management strategy developed in 1986 by Motorola USA. It is widely used in many sectors of industry by 2010. Six Sigma seeks to improve the quality of process outputs by removing & identifying the causes of defects and minimizing variability in manufacturing and business processes. The philosophy of  Six Sigma is that if you measure how many defects are in a process, you can figure out how to systematically eliminate them and get as close to perfection. In order for a company to achieve Six Sigma, it cannot produce more than 3.4 defects per million number of  opportunities. Six Sigma is a focused, rigorous and highly effective implementation of proven quality techniques & principals. Six Sigma aims for virtually error-free business performance. Company performance is measured by the sigma level of their business processes.

Six Sigma relies on tried and true methods that have been used for decades. Six Sigma helps the organization making more money by improving customer efficiency and value. To link this objective of Six Sigma with quality requires a new definition of quality: the value added by a productive endeavor. This quality may be expressed as potential quality and actual quality. Potential quality is the maximum possible value added per unit of input, however the actual quality is the current value added per unit of input. The difference between potential & actual quality is waste. Six Sigma focuses on improving quality i.e., reducing waste with the help of producing products and services better, faster, and cheaper.

Six Sigma Methodologies

Six Sigma has two key methodologies: DMAIC and DMADV, both inspired by Deming’s Plan-Do- Check-Act Cycle.

1. DMAIC is improving an existing business process;
2. DMADV is creating new product or process designs.

DMAIC (Define- Measure – Analyze – Improve – Control)

The basic DMAIC methodology consists of the following five steps:

• Define process improvement goals that are consistent with customer demands and the enterprise strategy.
• Measuring key aspects of the current process and collecting relevant data.
• Analyze the data to verify cause & effect relationships. Determine what the relationships are, and attempt to ensure that all factors are considered.
• Improve or optimize the process based upon data analysis using techniques like Design of Experiments.
• Control to ensure that any deviations from target are corrected before they result in defects. Set up pilot runs to establish process capability, move on to production, set up control mechanisms and continuously monitor the process.

DMADV (Define – Measure – Analyze – Design – Verify)

This is also known as DFSS – Design for Six Sigma. The basic methodology consists of the following five

• Define design goals that are consistent with customer demands and the enterprise strategy.
• Identify & measure CTQs (characteristics that are Critical To Quality), product capabilities, production process capability, and risks.
• Analyze to design & develop alternatives, create a high-level design and evaluate design capability to select the best design.
• Detailed designs, optimize the design & plan for design verification.
• Verify the design, setting up a pilot run, implementing the production process and handing it over to the process owners.

Six Sigma identifies two main key roles for its successful implementation as below.

Six Sigma Black Belts

The Certified Six Sigma Black Belts are professionals who can explain Six Sigma philosophies and principles, including supporting systems and tools. A Black Belt demonstrate team leadership, understand team dynamics and assign team member roles & responsibilities. Black Belts have a thorough understanding of all aspects of the DMAIC model in accordance with Six Sigma. They have the knowledge of Lean enterprise concepts and are able to identify non value added elements and activities and are also able to use specific tools.

Six Sigma Green Belts

The Six Sigma Green Belt operates in support of or under the supervision of a Six Sigma Black Belt, analyzes and solves quality problems and is involved in quality improvement projects. A Green Belt is someone with at least three years of work experience who wants to demonstrate his or her knowledge of Six Sigma tools and processes.

Lean Six Sigma

 In recent years, Six Sigma has sometimes been combined with lean manufacturing (management) to yield a methodology named Lean Six Sigma. Lean is a philosophy & set of management techniques focused on continuous “eliminating waste” so that every process, task or work action is made “value adding” (the real output customer pays for!!) as viewed from customer perspective. Lean “waste elimination” targets the “Eight Wastes” namely:

• Overproduction – Making more than what is needed by customer / market demand
• Over-processing – Doing more to a product/service (but not perceived as value by customer)
• Waiting – For material, information, people, equipment, procedures, approvals and more
• Transportation – Movement of products / items during or after production
• Defects – Errors, mistakes, non-complying products, services, documents, transactions
• Rework and Scrap – Products, transactions or outputs not meeting specifications and have to be fixed, redone, rectified, marked down or scrapped / unusable.
• Motion – Mainly people, document movement, searching etc.
• Inventory – Buffer stocks or resources (Raw, Work in process, FG, Bench staff etc.,)
• Unused Creativity – People knowledge and skills that are not utilized by the company

Wastes make the organization slow, inefficient and uncompetitive. Lean methods help to remove / reduce waste and contributes to driving “business agility” (velocity) through smooth work flow across the organization resulting in rapid fulfillment of customer needs in an optimum manner.