Quality Magazine

Quality Management: Get the Most Out of Six Sigma

March 18, 2006

Since its success at General Electric in the early '80s, Six Sigma has become the process improvement method of choice within manufacturing environments. But a growing chorus of experts has begun to wonder whether their often sizable investment in pursuing near-zero defects is paying off. Here are nine actions to ensure Six Sigma lives up to its promise.

1. Make sure that employees understand the concept of process control.

Invite a cross-section of engineers, supervisors, manufacturing managers and shop-floor personnel into your office and ask them a few simple questions: What is quality? What does variation mean, and how does it impact quality? What are Cp and Cpk, and how are they calculated? What is the difference between special cause and common cause? What does Six Sigma actually refer to?

Don't be surprised if your questions evoke shrugs. Very few people in organizations understand the basics of process control. Many quality practitioners and consultants make the mistake, when talking to line operators and other workers, of immediately plunging into the deep waters of "normal curves," and flow charts. Most employees don't have a statistical background, which explains why variation reduction remains a key manufacturing challenge. Before beginning a Six Sigma initiative, everyone involved in the effort should understand the basic terminology and concepts.

2. Use a common, standardized methodology for Six Sigma initiatives.

Every organization has countless procedures and processes in place to minimize product and service variance. Yet, in many organizations there is scant evidence of a uniform process for controlling variance in how information is gathered, organized and analyzed to pinpoint root causes of problems and take corrective action.

Pick up just about any book about process control and you will find many focus on tools and techniques. But apart from general exhortations to "define, measure, analyze, improve and control (DMAIC)," there is little substance about how these tools and techniques fit together in an integrated, common process for achieving Six Sigma.

Take the case of a high-tech electronics manufacturing facility, with a diverse range of processes, supported by a staff of competent engineers. The engineers were well versed in statistics and all the nuances of variation reduction. But, without a common language and approach, it was difficult to manage all the variation reduction initiatives that the plant sought to put in place. Once a common, visible Six Sigma process was introduced across the portfolio of projects, both teamwork and results, improved. Six Sigma tools and techniques then were effectively transferred, and others outside the engineering group were enlisted to support projects.

3. Concentrate on key product attributes.

If you were a soft-drink manufacturer, which product attributes would be decisive in satisfying your customers? Without an answer, and without a common understanding of the "why" behind the answer, you risk consuming a great deal of time and resources attempting to control the wrong attribute.

Think of operators on the manufacturing floor. If they do not understand why it is important to control a certain product attribute and what the downstream long- and short-term effects might be of high variation related to the attribute, it would be difficult to gain buy-in and support for any process control efforts.

Case in point: A coated steel manufacturer experienced difficulty getting its operators to measure and control coating thickness, a critical product attribute. Because the failure to successfully control this attribute would be evident only after several years, there was little interest in the standard operating procedures supplied by quality control for measuring and controlling this attribute. Concentration on coating thickness improved after in-depth technical discussions with those responsible for researching and designing the product, selling and making it, along with those customers who purchased it.

Next, to assess the downstream impact of off-spec thickness, the manufacturer made field visits to both poor-performing installations and the accelerated testing facility-putting the focus squarely on the product attribute during critical manufacturing steps. The actions helped everyone clearly see-and accept-the "why." Variation related to coating thickness quickly declined.

4. Understand how processes and equipment deliver key product attributes.

Knowing how machines and processes work is a fundamental requirement for any process control or Six Sigma initiative and should go well beyond the level of "push this button and let the machine fly." Variation often comes from many interacting variables in a system. This puts a premium on detailed knowledge of what these variables are, what settings the specification calls for, and how and why these variables impact the critical product attributes.

One client had an urgent need to solve a problem related to an expensive, sophisticated power generator. The client was advised to structure up-front technical training in order to provide everyone involved in the problem-

solving initiative with a common understanding of how the equipment worked.

The client felt that the training would be unnecessary, given that the machine had been in service for more than five years. Nevertheless, the company planned a half-day of technical training, which began by having the electricians, fitters, engineers, quality personnel and operators prepare a "teach" on how the equipment worked. Large-format technical drawings were posted on the wall to facilitate the learning-transfer process.

First, the electricians stood up to explain the equipment. Ten minutes into the electricians' presentation, it became obvious that their understanding of how the machine functioned and of the basic terminology related to machine parts differed from that of the other groups. No two groups could agree.

The half-day session turned into a full day, which proved highly valuable to participants. The need for a common, troubleshooting approach surfaced during the session. Subsequent training led to significant improvements in equipment performance.

5. Standardize manufacturing processes.

Before undertaking any problem-solving or design-of-experiment initiatives, the process needs to be standardized. There is only one right way to run the process; therefore, the process must be run the same way from operator to operator, shift to shift, day to day, and week to week. The process must be understood, agreed upon by everyone-and consistently deployed. Most operators understand the dictum that, "there is one best way to run the line." Unfortunately, they also believe their way is best.

After struggling for weeks to standardize the output of a large, complex machine used for rolling steel, a plant engineer threw up his hands and called the supplier for help. After a site inspection, the supplier's troubleshooter rendered his verdict: the machine was so different from the one that had been supplied originally that a fix could not be made. Years of "Band-Aiding" had caused massive deviations from the machine's design specification-another victim of helter-skelter problem solving.

6. Use effective tools to remove special-cause problems.

It's an all-too-typical scenario: The processes are standardized, data is collected and teams of employees stand ready to solve the remaining problems. Yet, getting to the root cause of the problems remains illusive.

Many techniques, such as cause-and-effect or fishbone diagrams, brainstorming and decision trees, masquerade as fully formed problem-solving and decision-making approaches. In reality, such techniques are job aids that, however useful, are not integrated platforms for taking problem solvers from systematically gathering facts, making judgments about them, homing in on root causes and then taking action.

With the current spate of popular tools, it is important to recognize that there are different tools required for special- vs. common-cause problems. In some cases we need to be versed in tools related to both situations.

7. Provide problem-solving training.

A great gap exists in many companies between having the right set of tools and having manufacturers properly trained to use them. Putting employees through a two- or three-day training session may provide an understanding of the concepts involved, but rarely will it provide the skill level to transfer those concepts to the job. Just as good craftspeople must be taught how to use the "tools of the trade," so too must good problem solvers and decision makers be taught. Asking the right questions, in the proper sequence, is a disciplined skill.

About two weeks of intensive training enables most people to reach a base competency level in problem solving and decision making. The latest approaches to training process-control gurus and Six Sigma black belts span a minimum of eight weeks and combine formal training with hands-on project work. In my experience, the best results come from combining formal skill development with on-the-job application, coaching and ongoing mentoring by seasoned professionals. It is how master tradespeople teach apprentices.

8. Involve the right people.

Problem solving begins not just with a clear definition of the problem, but with having the right people involved-those with access to the right technical and operating data. Involving the right people ensures that you have the right information, along with buy-in and commitment.

Take, for example, a team of skilled production workers that set out to attack a scrap problem on the plant floor. After extensive analysis, they isolated the likely root cause of the deviation, but when they proceeded to verify their conclusion with the line operator, to their dismay they found that the analysis was off base. The suspected culprit was a piece of equipment that had been removed months earlier. If only they had spoken to the operator before beginning their analysis.

9. Align the performance system.

Many organizations fail to understand the criticality of managing the performance environment to sustain top performance and continually improve results. Such results require a commitment to ongoing technical training; availability of the most effective tools and equipment in the most appropriate locations; the existence of clear and commonly understood expectations; the immediacy and quality of feedback; and the use of positive and negative consequences to encourage expected behavior.

One company went to great lengths to provide a positive performance system for its change initiatives. It did everything by the book-clear goals; training; the latest equipment; accurate, frequent feedback; and the right balance of positive and negative consequences to produce desired behavior. But the managers' and supervisors' attitudes really distinguished this company. They believed that to be credible they had to master the same Six Sigma skills as the people they managed. This attitude drove their management team with a relentless and passionate approach to develop themselves as practitioners of the many tools and techniques needed to be successful

in Six Sigma, and to create a high-achieving performance environment. Q

Quality Tech tips

1. Before beginning a Six Sigma initiative, be sure everyone involved in the effort understands the basic terminology and concepts.

2. Knowing how machines and processes work is a fundamental requirement for any process control or Six Sigma initiative and must go well beyond the level of "push this button and let the machine fly."

3. Manufacturing processes should be standardized before any problem-solving or design-of-experiment initiatives take place.