Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001

11. SIX SIGMA QUALITY

 

· Developed by Motorola

 

· A strategy to target quality problems

 

· In simple terms,

 

 

· This can be summarized as 6σ of variance alone ignores the drift of the process centre. Assuming the process centre varies by +/-1.5σ results in a more accurate model of production.

 

· The steps in implementation are,

  1. 1. Identify critical characteristics through such functions and activities as marketing, industrial design, R&D engineering, etc.
  2. 2. Identify the product elements that influence the critical characteristics defined in step 1.
  3. 3. Define the process elements that influence the critical characteristics defined in step 2.
  4. 4. Establish maximum tolerances for each product and process element defined in steps 2 and 3.
  5. 5. Determine actual capability of the elements presented in steps 2 and 3.
  6. 6. Assume Cp >= 2 and Cpk >= 1.5.