Six Sigma Overview

Six Sigma is a philosophy:

Why isn’t “99% acceptable” good enough...??

- 20,000 lost articles of mail every hour.

- 15 minutes each day of unsafe drinking water.

- 5,000 incorrect surgical procedures per week.

- 4 or more accidents per day at major airports.

- 200,000 wrong drug prescriptions each year.

- 7 hours each month without electricity.

History of Six Sigma

6 Sigma manufacturing philosophy came from Motorola

They recognised that sufficient process improvement would not occur using a conventional approach to quality. It was developed to help them reduce variation within a process by focusing effort on improving inputs to a process rather than reacting to outputs.

The process was failing the customer expectations Traditionally, processes aimed for process capability of 3 to 4 sigma (Cpk=1.0 to 1.33 or 93% to 99.3% acceptable) The customer received 6200 defective product per million at best Processes now aim for 6 sigma (Cpk=2) The customer would receive 3.4 defective product per million

Understanding Variability

Variation exists in everything. Even the best machine cannot make every unit exactly the same.

Improved capability, becomes a necessity, due to the need of :

improved designs

lower costs

better performance

All of this leads to the need of tighter tolerances

This means that the ability to operate to a tight tolerance, without producing defects becomes a major advantage

6 Sigma Improvement Methodology

Define:

Define terms of reference (Charter the project)

Team / customer / project charter

Brain storming

Mind maps

Affinity diagrams

High level Process Maps

Systematic diagrams / Fault tree

Business Process Mapping

Define customer requirements (Voice of the customer)

QFD Quality Function Deployment

Define terms of reference (charting a project)

What you can deliver to the customer and the support you need from the customer to facilitate a successful improvement (contract of engagement)

Brain storming, Mind maps, Affinity diagrams, High level Process Maps, Systematic diagrams / Fault tree, Business Process Mapping Tools to explore a problem, project or current thinking.

Tools to group those ideas logically.

Then define a route map to improvement, the risk involved and how to mitigate that risk.

Define customer requirements (Voice of the customer) QFD Quality Function Deployment, is a method of defining what the customer needs, what is critical to there business success & prioritise objectives to meet the customer need.

Measure

Define terms of reference (charting a project) What you can deliver to the customer and the support you need from the customer to facilitate a successful improvement (contract of engagement)

Brain storming, Mind maps, Affinity diagrams, High level Process Maps, Systematic diagrams / Fault tree, Business Process Mapping Tools to explore a problem, project or current thinking. Tools to group those ideas logically. Then define a route map to improvement, the risk involved and how to mitigate that risk.

Define customer requirements (Voice of the customer) QFD Quality Function Deployment, is a method of defining what the customer needs, what is critical to there business success & prioritise objectives to meet the customer need.

Voice of the process (7 quality tools) Tally charts, Bar charts, Pareto, Run charts, Control charts, Cause & effect, Check sheets.

Evaluate measurement systems Gauge R&R

Every process has variation and measurement system, tools & cmm are no exception.

Typical your measurement process needs to be ACCURATE, REPEATABLE & REPRODUCIBLE to less than 10% of the tolerance you are trying to measure to & proven to be so.

Select measures of performance QFD Quality Function Deployment is a method of defining what the customer needs and what is critical to there business success and prioritising performance measures to support the customers need.

Analyze:

Investigate source of variation (Special cause / Common causes)

Stratification of data to get information Cause & effect CP & CPK Fault tree Contingence analysis FMEA (Failure Mode Effect Analysis) Design of experiments (DOE) Detailed process maps

Investigate source of variation (Special cause / Common causes)

Special cause variation are the one off, occasional and obvious cause of a process / quality problems.

Common cause variation are the day in day out causes of process problems, because the process is not stable enough, they are hidden (these form 80% of process problems)

Conventional non-conformance management systems seek to solve special cause variation (e.g. concessions) - but these only represent 15 - 20% of the total variation.

Six Sigma addresses all variation.

Improve:

Prioritise improvements

Impact Vs Effort

Brainstorming

Affinity diagrams

Solution selection matrix

Tactical implementation plans

Deliver improvements (reduce variation systematically)

Prioritise improvements

Tool commonly in uses are, Impact Vs Effort, Brainstorming, Affinity diagrams, Solution selection matrix.

These tools help define the best method to meet the customer need (as defined in the QFD)

Tactical implementation plans Deliver improvements to reduce variation systematically i.e. make a change, note the improvement and make the next improvement.

Critical we need to establish that any change is a change for the good.

Control:

Control the process

Recover

Control plans

Escalation process

Prevent

Poke yoke (mistake/ error proof)

Monitor

Control charts

Checksheets

Documentation and Standardisation

Control the process

Recover, Control plans, Escalation process.

Prevent by Poke yoke (Error proof the process) to fundamentally remove the rood causes of process variation in line with six sigma methodology.

Monitor, Control charts, Checksheets, Documentation and Standardisation, to ensure that stable process is maintained and that the process does not degrade.

The objective is to remove the root causes of process variation, management are only left with a few critical input variables in the process that need controlling and not all inputs as before.

Where does Six Sigma fit with Lean ?

Lean and Six Sigma both seek to deliver business improvement

They are different in the methods used and tools employed Lean typically address the total manufacturing environment Six sigma typical address the root cause of process variation

There is significant benefit from using the most appropriate tools and improvement methodology to meet the customer requirements

For more details of how to attain a Lean Six Sigma Black Belt Certification, Click here