QMS, ISO and Six Sigma

Any Quality Management System must satisfy four requirements.

1. Processes must be defined and their procedures appropriately documented.

2. Processes are fully deployed and implemented as stated.

3. Processes are effective in providing the expected results.

4. An Improvement System must be in place to improve Processes.

ISO 9001 Standard

ISO 9001 is based on eight Quality Management Principles.

1. Focus on your customers

2. Provide leadership

3. Involve your people

4. Use a process approach

5. Take a systems approach

6. Encourage continual improvement

7. Get the facts before you decide

8. Work with your suppliers

Six Sigma is a Project Management Process

If a QMS system is in place, an organization may be confronted with a major challenge(s) which crosses Organizational Boundaries. Six Sigma is an effective Project Management tool for addressing such challenges.Six Sigma may be used in addressing a variety of such major challenges. There are two situations, in particular, where Six Sigma has been shown to be particularly effective:

1. A major Quality Issue whose resolution requires an effort which crosses organizational boundaries.

2. New Product Development for complex products in rapidly evolving Market conditions.

What is a Sigma?

Determining sigma levels of processes (one sigma, six sigma, etc.) allows process performance to be compared throughout an entire organization, because it is independent of the process. It is merely a determination of opportunities and defects, however the terms are appropriately defined for that specific process.
Sigma is a statistical term that measures how much a process varies from perfection, based on the number of defects per million units.
One Sigma = 690,000 per million units
Two Sigma = 308,000 per million units
Three Sigma = 66,800 per million units
Four Sigma = 6,210 per million units
Five Sigma = 230 per million units
Six Sigma = 3.4 per million units
In formulae for control limits and process capabilities, sigma is the symbol for Standard Deviation, calculated from the squares of the deviations of measured samples from the mean value (or sometimes by other methods using 'magic' numbers). For a normally distributed output, 99.7% would be expected to fall between +/-(3 x sigma) levels.

What is Six Sigma?

What does it mean to be "Six Sigma"? Six Sigma at many organizations simply means a measure of quality that strives for near perfection. But the statistical implications of a Six Sigma program go well beyond the qualitative eradication of customer-perceptible defects. It's a methodology that is well rooted in mathematics and statistics.

The objective of Six Sigma Quality is to reduce process output variation so that on a long term basis, which is the customer's aggregate experience with our process over time, this will result in no more than 3.4 defect Parts Per Million (PPM) opportunities (or 3.4 Defects Per Million Opportunities – DPMO). For a process with only one specification limit (Upper or Lower), this results in six process standard deviations between the mean of the process and the customer's specification limit (hence, 6 Sigma). For a process with two specification limits (Upper and Lower), this translates to slightly more than six process standard deviations between the mean and each specification limit such that the total defect rate corresponds to equivalent of six process standard deviations.

Many processes are prone to being influenced by special and/or assignable causes that impact the overall performance of the process relative to the customer's specification. That is, the overall performance of our process as the customer views it might be 3.4 DPMO (corresponding to Long Term performance of 4.5 Sigma). However, our process could indeed be capable of producing a near perfect output (Short Term capability – also known as process entitlement – of 6 Sigma). The difference between the "best" a process can be, measured by Short Term process capability, and the customer's aggregate experience (Long Term capability) is known as Shift depicted as Zshift or sshift. For a "typical" process, the value of shift is 1.5; therefore, when one hears about "6 Sigma," inherent in that statement is that the short term capability of the process is 6, the long term capability (Ppk here) is 4.5 (3.4 DPMO – what the customer sees) with an assumed shift of 1.5. Typically, when reference is given using DPMO, it denotes the Long Term capability of the process, which is the customer's experience. The role of the Six Sigma professional is to quantify the process performance (Short Term and Long Term capability) and based on the true process entitlement and process shift, establish the right strategy to reach the established performance objective

As the process sigma value increases from zero to six, the variation of the process around the mean value decreases. With a high enough value of process sigma, the process approaches zero variation and is known as 'zero defects.'

D - Define Phase: Define the project goals and customer (internal and external) deliverables.

  • Define Customers and Requirements (CTQs)
  • Develop Problem Statement, Goals and Benefits
  • Identify Champion, Process Owner and Team
  • Define Resources
  • Develop Project Plan and Milestones
  • Develop High Level Process Map

M - Measure Phase: Measure the process to determine current performance; quantify the problem.

  • Define Defect, Opportunity, Unit and Metrics
  • Detailed Process Map of Appropriate Areas
  • Develop Data Collection Plan
  • Validate the Measurement System
  • Collect the Data
  • Determine Process Capability and Sigma Baseline

A - Analyze Phase: Analyze and determine the root cause(s) of the defects.

  • Define Performance Objectives
  • Identify Value/Non-Value Added Process Steps
  • Identify Sources of Variation
  • Determine Root Cause(s)

I - Improve Phase: Improve the process by eliminating defects.

  • Develop Potential Solutions
  • Define Operating Tolerances of Potential System
  • Assess Failure Modes of Potential Solutions
  • Validate Potential Improvement by Pilot Studies
  • Correct/Re-Evaluate Potential Solution

C - Control Phase: Control future process performance.

  • Define and Validate Monitoring and Control System
  • Develop Standards and Procedures
  • Implement Statistical Process Control
  • Determine Process Capability
  • Develop Transfer Plan, Handoff to Process Owner
  • Verify Benefits, Cost Savings/Avoidance, Profit Growth
  • Close Project, Finalize Documentation
  • Communicate to Business