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AST - Advanced Statistical Techniques: Failure Pattern
Six Sigma - 6 Sigma
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Six Sigma - software and consultancy for costs and defects reduction.
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Six Sigma (a registered service mark and trademark of Motorola)
is a methodology to manage quality losses from business process variations that
cause an unacceptable deviation from the target and a resultant defect; and to systematically
drive improvements towards managing variation to eliminate those defects. The objective
of Six Sigma is to minimize the loss-to-society by delivering high target performance,
high reliability and value-add to the customer. The word sigma is a statistical
term that denotes how far a given process metric deviates from the target. This
distance measures how many "defects" there can be in the process. The larger sigma
gets, the lesser the number of defects. Thus, by knowing the current sigma, effort
can be directed to reduce this deviation to get as close to "zero defects" as possible.
While it may not be possible to achieve zero defects, to achieve Six Sigma Quality,
a process must produce no more than 3.4 defects per million opportunities (dpmo).
An "opportunity" is defined as a chance for nonconformance or not meeting the required
specifications.
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This means a process must be nearly flawless in executing our key
processes. Six Sigma focuses on the improvement of business processes so that implementers
achieve extraordinary ongoing benefits of tens and hundreds of millions of dollars
per annum. These financial benefits are achieved by increasing quality, reducing
variation, reducing cycle times, eliminating waste, encouraging innovation, tightening
customer relationships, and strengthening corporate cultures. Businesses embarking
Six Sigma projects have “Champions” who are responsible for supporting, aligning
and integrating the Six Sigma activities in their organization. Champions are trained
in the essentials of the Six Sigma methodology, especially focusing on how to select
projects that are aligned with business goals. Champions in turn select and mentor
Six Sigma project leaders who are called “Belts” and ensure the Belts have the training
and resources they need to successfully lead Six Sigma projects. Belts can be Green
Belt, Black Belt or Master Black Belt.
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Six Sigma programs are implemented through the DMAIC process consisting of: |
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Define |
What is important?
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Measure |
How are we doing? |
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Analyze |
What is wrong? |
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Improve |
What needs to be done? |
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Control |
How do we maintain performance? |
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Define |
The Six Sigma DMAIC method is about solving a problem (Big Y) defined in measurable
terms with many variables (Xi) each with weighting a, b, c, …, n, etc. So
Y = Sum (a.X1, b.X2, c.X3, …, n.Xn).
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In the Define phase, the Six Sigma project team identifies a project based on business
objectives and the customers of the process and their needs and requirements. The
team identifies CTQ (Critical To Quality) characteristics that have the most impact
on the business and creates a process map for improvement.
Implementation Tools:-
- Pareto Chart
- Process Flow Chart
- FMEA
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Measure |
The Belt leading the project determines the viability (capability and stability)
of the project Y and how well it can be measured. If the project has a clear definition
and metric, the Key Process Steps are studied and the Key Inputs identified for
each process. Key Inputs are sorted to prioritize a short list for further study.
An important aspect of Measure is to identify the gap between the current process
performance and the desired process performance.
Implementation Tools:-
- MSA - Measurement System Analysis
- Trend Chart
- Statistical Process Control
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Analyze |
In this phase, the team evaluates on how to reduce the gap between the current process
performance and the desired process performance. This is often done through the
careful analysis of process data. Six Sigma analysis techniques are very important
and many are available from iCT-M.
Implementation Tools:-
- Fishbone Diagram
- Histogram
- Regression Analysis Training
- Design Of Experiments
- Hypothesis Testing
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Improve |
Problem causes identified in the Analyze phase are overcome with creative improvements.
Implementation Tools:-
- Brainstorming
- Systems Diagrams
- Error-Proofing
- Corrective Action Matrix
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Control |
In the Control phase, mechanisms are put in place to ensure that the key variables
are maintained within acceptable operating ranges over time. Thus, maintaining the
gains. A project hand off process, reaction plans, and training materials are developed
to ensure performance and long-term project savings are realized.
Implementation Tools:-
- Control Plan Methodology
- Statistical Process Control
- FMEA
- 5S Housekeeping
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