Six Sigma
a customer focused, well defined problem solving methodology supported by a handful of powerful analytical tools
Continuous
... [Show More] Improvement
driven by the execution of carefully selected projects
Brainpower
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Goal of Six Sigma
to take small steps forward and no steps backward
Formal Six Sigma Definition
a business improvement approach that seeks to find and eliminate causes of mistakes or defects in business processes by focusing on process outputs that are of critical importance to customers
Who coined "Six Sigma"?
Motorola
Sigma Level
measures the capability of the process to perform defect free work; the higher, the better quality
Defect
anything that results in customer dissatisfaction
Purpose of Six Sigma
to better serve customer needs and expectations thereby providing increasing value to the customers and ensuring repeat business
Six Sigma Approach Requirements
1. Not just statistics, but changes in culture of the organization;
2. A deep commitment from the highest levels of management;
3. A tolerance for endlessly questioning the validity of sacred company beliefs and the traditional ways
For Six Sigma to be Effective
1. There must be a process in place;
2. The process must be brought into control statistically;
3. The processes must be improved (by reducing variation within the controlled processes and bringing them closer to the target)
Six Sigma Structured Steps
DMAIIC: Define, Measure, Analyze, Improve, Implement, Control
Theory of Profound Knowledge
Dr. Deming claims to be essential to for any organization that desired to be competitive in today's marketplace
Knowledge of Systems
1. A system is a network of interdependent components that work together to try to accomplish an aim;
2. Systems are management's responsibility;
3. Management's job is to optimize the entire system over time
Knowledge of Variation
1. Variation is the voice of the system or process;
2. Use statistics to find special and common causes of it;
3. Reducing variation reduces costs
When people do not understand variation
1. See trends where there are no trends;
2. Blame and give credit to others for things over which they have little or no control;
3. Build barriers, decrease morale, and create an atmosphere of fear;
4. Never be able to fully understand past performance, make predictions about the future and make significant improvements in the process
Knowledge of Psychology
1. People want to do a good job, contribute, and have pride and joy in their work;
2. Need to tap into intrinsic motivation;
3. Must drive out fear and build trust
Knowledge of Knowledge
Rational prediction requires theory and we build knowledge through systematic revision and comparison of theory based on comparison of prediction with observation
Common Cause Variation
refer to situations, usually within those systems and processes that are more ongoing, chronic, and persistent
Special Cause Variation
refer to sentinel events, one-time occurrences, or other unique out-of-the-ordinary circumstance
Stable Process
normal variation; predictable, in control, have known process capability
Control
predictability
Basic Theorem of Variation
If you always do what you've always done, you'll always get what you've always got
Corollary to the Basic Theorem of Variation
expect a change, requires change
Process Monitoring
must know central location, spread, shape, relationship of variation to time
Histogram
a graphical representation of data in a bar chart format; used to observe the shape of data
3 standard deviations
contains 99.73 percent of values, represents the expected limits of common cause variation necessary for stable and predictable process
Six Sigma Quality
6 standard deviations in each direction; 3.4 defects per million
Describing data
need location, spread, shape, variation over time
Target
what organizations promise customers; nominal; customer requirement
Shape
histogram must be compared to expected shape, especially if not a bell curve
Control charts
statistical tool which shows the amount and type of variation present in any process that is being monitored; describe the representative nature of a stable predictable, in control process
Control Limits
describe the representative nature of a stable process; identify the expected limits of normal, random, or chance variation that is present in the process; set by the process
Specification Limits
describe the characteristics the product (or process) must have in order to conform to customer requirements or to perform properly in the next opreation
Out of Control Checks
1. Is the shape of the histogram what was expected?
2. Are all the sample averages between the control limits for averages?
3. Are all the sample ranges between the control limit for ranges?
4. Is the pattern of variation as time goes by random? (Western Electric Rules); passing these means there are no special cause variations
Western Electric Rules
AT&T Quality Control handbook; conditions indicate that the process is out of control
Process Capability
defines limits we would normal expect virtually all individuals to fall within; ability of the combination of people, machines, methods, materials, and measurements to produce a product or service that will consistently meet design specifications
Measuring Process Variability
the proportion of output that can be produced within design specifications; a long term prediction; measure of uniformity; can be measured only if all special causes have been eliminated and the process is in a state of statistical control
Components of Process Capability
design specifications, centering of natural variation, range or spread of variation
Capability Measures
short term show the capability at a specific instance in time; long term show the expected capability of the process based on statistical projections using inherent process variability
Percent Non-Conforming
reflects the proportion of the population that we normally expect not to meet the process specifications; tail areas of normal curve [Show Less]