SKEDSOFT

Six Sigma

The Six Sigma Movement

a)      The six sigma movement began in 1979 at Motorola when an executive declared that “the real problem [is]…quality stinks.” With millions of critical characteristics per integrated circuit unit, the percentage of acceptable units produced was low enough that these quality problems obviously affected the company’s profits.

b)      In the early 1980s, Motorola developed methods for problem-solving that combined formal techniques, particularly relating to measurement, to achieve measurable savings in the millions of dollars. In the mid-1980s, Motorola spun off a consulting and training company called the “Six Sigma Academy” (SSA).

c)       In 1992, Allied Signal based its companywide instruction on Six Sigma Academy techniques and began to create job positions in line with Six Sigma training levels. Several other companies soon adopted Six Sigma Academy training methods, including Texas Instruments and ABB.

d)      Also during the mid-1990s, multiple formal methodologies to structure product and process improvement were published. These methodologies have included Total Quality Development), Taguchi Methods the decision analysis-based framework (e.g., Hazelrigg 1996), and the so-called “six sigma” methodology (Harry and Schroeder 1999).

e)      All these published methods developments aim to allow people involved with system improvement to use the methods to structure their activities even if they do not fully understand the motivations behind them.

f)       In 1995, General Electric (GE) contracted with the “Six Sigma Academy” for help in improving its training program. This was of particular importance for popularizing six-sigma because GE is one of the world’s most admired companies.

g)      The Chief Executive Officer, Jack Welch, forced employees at all levels to participate in six sigma training and problem-solving approaches. GE’s approach was to select carefully employees for Black Belt instruction, drawing from employees believed to be future leaders. One benefit of this approach was that employees at all ranks associated six -sigma with “winners” and financial success.

h)      In 1999, GE began to compete with Six Sigma Academy by offering six sigma training to suppliers and others. In 2000, the American Society of Quality initiated its “black belt” accreditation, requiring a classroom exam and signed affidavits that six sigma projects had been successfully completed. Montgomery (2001) and Hahn et al. (1999) have commented that six sigma training has become more popular than other training in part because it ties standard statistical techniques such as control charts to outcomes measured in monetary and/or physical terms

i)        Derives in part from the fact that it teaches an assemblage of techniques already taught at universities in classes on applied statistics, such as gauge repeatability and reproducibility (R&R), statistical process control (SPC), design of experiments (DOE), failure modes and effects analysis (FMEA), and cause and effect matrices (C&E).

j)        All of the component techniques such as SPC and DOE are discussed in Pande et al. (2000) and defined here. The techniques are utilized and placed in the context of a methodology with larger scope, i.e., the gathering of information from engineers and customers and the use of this information to optimize system design and make informed decisions about the inspection techniques used during system operation.

k)      Pande et al. (2000) contributed probably the most complete and explicit version of the six sigma methods in the public domain. Yet even their version of the methodology (perhaps wisely) leaves implementers considerable latitude to tailor approaches to applications and to their own tastes. This lack of standardization of methodologies explains, at least in part, why the American Society for Quality still has only recently introduced a six sigma “black belt” certification process. An exception is a proprietary process at General Electric that “green belt” level practitioners are certified to use competently.

 

Examplehow do six sigma and lean production relate?

Answer:

a)      Six-sigma is a generic method for improving systems or designing new products, while lean manufacturing has a greater emphasis on the best structure, in Toyota’s view, of a production system. Therefore, six sigma focuses more on how to implement improvements or new designs using statistics and optimization methods in a structured manner.

b)      Lean manufacturing focuses on what form to be implemented for production systems, including specific high-level decisions relating to inventory management, purchasing, and scheduling of operations, with the goal of emulating the Toyota Production System.

c)       That being said, there are “kaizen events” and “value stream mapping” activities in lean production. Still, the overlap is small enough that many companies have combined six sigma and lean manufacturing efforts under the heading “lean sigma.”