Category Archives: six sigma

Lean Manufacturing


Six-Sigma is a rigorous, disciplined, data-driven methodology that was developed to enhance product quality and company profitability by improving manufacturing and business processes. Six-Sigma uses statistical analysis to quantitatively measure how a process is performing. That process can involve manufacturing, business practices, products, or service. To be defined as Six Sigma means that the process does not produce more than 3.4 defects per million opportunities (DPMO) – which translates to 99.9997% efficiency.

Six Sigma Concepts

The Six Sigma concept was developed by Motorola in 1986 with the stated goal of improving manufacturing processes and reducing product defects and variation. The underlying goal was to achieve near quality perfection with 99.9997% of variable values within specifications.

Building on earlier quality improvement methods, Six Sigma assumes the following:

  • Ongoing efforts to achieve stable, predictable process results are essential for business success
  • Manufacturing and business processes have characteristics that can be measured, analyzed, improved, and controlled
  • Sustained quality improvement requires commitment from the entire organization.
  • Six-Sigma Implementation

    To achieve Six Sigma performance, the causes of manufacturing and business process defects and variation must be identified and eliminated. Two Six Sigma sub-methodologies were developed for this purpose:

  • DMAIC (Define, Measure, Analyze, Improve, Control) and
  • DMADV (Define, Measure, Analyze, Design, Verify).
  • 1. DMAIC – DAMIC is used to improve existing processes that are below specification.

  • Define the projects, the goals, and the deliverables to customers (internal and external). Describe and quantify both the defect and the expected improvement.
  • Measure the current performance of the process. Validate data to make sure it is credible and set the baselines.
  • Analyze and determine the root cause(s) of the defects. Narrow the causal factors to the vital few.
  • Improve the process to eliminate defects. Optimize the vital few and their interrelationships.
  • Control the performance of the process. Lock down the gains.
  • 2. DMADV– DMADV is used to develop new processes or products at Six Sigma levels. DMADV (alternatively known as DFSS [Design for Six Sigma]), can also be applied to existing processes that require more extensive improvement. [17]

  • Define: – Determine the project goals and the requirements of customers (external and internal).
  • Measure: – Assess customer needs and specifications.
  • Analyze: – Examine process options to meet customer requirements.
  • Design: – Develop the process to meet the customer requirements.
  • Verify: – Check the design to ensure that it’s meeting customer requirements.
  • Borrowing martial arts terminology, a key innovation of Six Sigma was the creation of a professional quality management hierarchy. This structure works to involve all levels of the organization in the success of Six Sigma projects:

  • Executive Leadership includes the CEO and other top management
  • Champions, drawn from upper management, are responsible for Six Sigma implementation across the organization.
  • Master Black Belts, identified by champions or by executive leadership, function as in-house coaches, mentors, and trainers; 100% of their time is devoted to Six Sigma to ensure business and leadership alignment
  • Black Belts focus on the application of Six Sigma methodology to specific projects; 100% of their time is devoted to Six Sigma
  • Green Belts are involved with Six Sigma implementation along with other job responsibilities.
  • Lean Sigma is a current industry trend in which a process is made lean through efficiency improvements before Six Sigma is applied to reduce variation.

    Related Blogs

    Integrating Project Management into a Six Sigma System

    Manufacturers and transactional firms share a drive to lower costs, reduce cycle time and offer a diverse product mix as they pursue higher profits and an increased market share in a growing global environment. Consumers (those paying for the end product) want products or services that are cheaper, readily available and of a quality that meets their expectations.

    A variety of systems – such as Total Quality Management, Total Quality Control and Six Sigma – have been implemented by organizations to help guide the efforts of creating new products, reducing product costs, improving manufacturing or organizational capabilities, realizing new market share or entering new markets. These systems rely on teams of people to identify the voice of the customer (both internal and external), taking into account the organization’s competencies. They also require an ongoing portfolio of projects aimed at creating revenue or reducing costs.

    While not all organizations implement these systems or keep them in their original form, many of the core ideas are adopted. Some organizations have integrated two or more systems. One melding of systems that holds significant promise is the integration of the Six Sigma methodology with the tools and processes of project management.

    The Six Sigma methodology DMAIC (Define, Measure, Analyze, Improve, Control) offers a structured and disciplined process for solving business problems. Six Sigma uses tools designed to identify root causes for the defects in processes that keep an organization from providing its customers with the consitent quality of products the customers require on time and at the most reasonable cost. The Six Sigma work is normally done through cross-function teams that manage the project. Yet the methodology does not address the management of the project itself.

    Project management’s tools and techniques focus on attributes of a project such as development, execution, control and closing. There is an assortment of tools that are used throughout the project to manage the project to completion.

    Six Sigma and Project Management

    With Six Sigma’s DMAIC process, a problem is first defined and quantified; then measurement data is collected to bound and clarify the problem; analytical tools are deployed to trace the problem to the root cause; a solution for the root cause is identified and implemented; and finally, the improved operations are subjected to ongoing control to prevent recurrence. The Six Sigma toolkit includes a variety of techniques, primarily from statistical data analysis and quality improvement. Design of experiments (DOE), failure mode and effects analysis (FMEA), cause-and-effect diagram (aka fishbone diagram, Ishikawa diagram), process flow diagram and gage repeatability and reproducibility (R&R) studies are among Six Sigma’s many tools.

    While the methodology of Six Sigma has proven effective in troubleshooting or improving existing processes using the DMAIC approach, there are challenges to confront when using Six Sigma. A company that relies solely on Six Sigma to run its projects may experience issues with control of the project process. A Master Black Belt was interviewed from a firm that utilized a pure Six Sigma system for its projects. The firm found that the majority of its projects were not being completed as the Six Sigma system would suggest. A lack of management support, insufficient resources and failure to understand the voice of customer (VOC) were some of the reported problems.

    The DMAIC approach focuses on controls for the improvements to the process, not the control of the project management process. “Project management is the application of knowledge, skills, tools, and techniques to project activities to meet project requirements,” according to the Project Management Institute.