Six Sigma Fundamentals: A Complete Introduction to the System, Methods, and Tools

In order for six sigma to survive, quality needs and overall strategic plans must exist in the organization. That is, there must be a system established in the organization to address the following:

• The link between quality function needs and overall strategic plan. Perhaps this is the most important issue in six sigma, but also in any endeavor that tries to address improvement of any kind. The focus here is on the quality function needs and the plan to support these needs, both now and in the future. Of course, these needs have to be in line with organizational aims, policies and plans. Some key considerations are: competition, cost, differentiation of product and usage of appropriate tools.

• The link between strategic plan and quality plan. The second most important issue in six sigma methodology is to correlate the strategic plans with an actual quality plan. That means that the organization either has, or is willing to develop, programs that deal with feedback, corrective action, data collection, processing and analysis and process and product development. In addition, it means that the organization has, or is willing to develop, an infrastructure to address such issues as organization, administrative support, control processes, internal audits, processes that identify customer needs and policies for inspection and testing.

• The theory of variation (common and special causes). It is beyond the scope of this book to have a lengthy discussion on variation. However, it is imperative that common (inherent) variation and special (assignable) variation are clearly understood. We associate common variation with random, material, prevalent, or normal variation; stable process; predictability; and process improvement through management intervention. On the other hand, we associate special variation with abnormal activity, unpredictability; and specific knowable causes. To understand variation we must also understand the components of variation: total variation = variation due to factor A + variation due to factor B + variation due to interaction AB + variation due to sampling error. Typical examples of common variation are:

  • Slight variation in raw material.

  • Slight machine vibration.

  • Lack of human perfection.

  • Variation in gage readings.

  • Variation in tooling.

  • Variation in operator skills.

• Special cause variations include:

  • Difference in machines or processes.

  • Batch of defective raw material.

  • Faulty machine setup.

  • Test equipment out of calibration.

  • Unqualified operator.

  • Part-time seasonal help.

  • Variable work force.

• Sometimes, it is possible to have variation due to a combination of both types, for example:

  • Major recession.

  • Equipment failure.

  • Price roll-back.

  • Employee downsizing.

• Some typical problems that the six sigma methodology may tackle, which confirm Deming's intuitive knowledge about variation and system thinking, include:

  • Poor design of product.

  • Poor instruction and poor supervision.

  • Failure to measure the effects of common causes and to reduce them.

  • Failure to provide the production workers with information in a statistical form.

  • Procedures not suited to the requirements.

  • Machines not suited to the requirements.

  • Settings of the machines chronically inaccurate.

  • Poor lighting.

  • Vibration.

  • Mixing product from streams of production.

  • Uncomfortable working conditions.

  • Shift of management's emphasis from quality to quantity.

  • Management's failure to face the problem of inherited defective material.

• The quality function mission is very important in strategic planning. The focus here is to make sure that the mission is aligned with the business strategy of the organization. In other words, the goal should be to establish an organizational mission statement in clear and simple language, so that it is understood by everyone in the organization (and by others) and so that the key driving forces to achieve customer satisfaction are identified in such a way that improvement must begin with:

  • Establishing priorities.

  • Defining organizational policies.

  • Analyzing trade-offs to resolve conflict with cost, delivery dates and other parameters. Maintaining continual improvement activity.

To appreciate even further the power and influence of the mission, let us look at its hierarchy:

• The mission. This is the broad policy of what the organization is existing for. The focus is on defining the quality mission and policy and providing quality awareness in the organization. It also involves setting goals to meet the mission, training and team concepts; measuring mission accomplishments, and determining the mission's relationship with vision, values and goals.

• The vision. This is made up of the key processes that assist in fulfilling this mission.

• The values. These are the key indicators to affirm the vision and the mission.

• The goals. The goals provide reinforcement to accomplish the mission.

In the context of the six sigma methodology, it is imperative to recognize that no organization can function without some (written or unwritten) quality principles and policies. So management must champion, if not outright, the key principles and policies for the entire organization. Typical issues are:

• The need for quality principles and the right policies (creed, beliefs, truths, rules, moral and ethical standards as they relate to the uniqueness of the organization's history, management and state of development).

• Appropriate approval from executive management (practiced by everyone).

• Participation by key managers.

• Understanding the need for customer relations (internal and external).

• Understanding the need for continual improvement.

• Understanding that everyone should be involved and concerned.

• Understanding the importance of quality.

• Understanding the importance of planning and organization.

• The metrics and goals that drive organizational performance. We cannot talk about performance in the abstract. Performance is always the result of a function. Therefore, for performance to be of value, the organization must have metrics and goals. The goals should be attainable, realistic, measurable and related to customer usage. The metrics, on the other hand, must be identified as real measures for these goals. Do not be afraid to take a risk if the risk is commensurable with the anticipated benefit. Fundamental requirements used as metrics may be the following items

  • Customer satisfaction.

  • The voice of the customer.

  • Economic ramifications.

  • Environmental and legal impact.

  • Worthiness.

  • Applicability.

A visual representation of the link between metrics and goals may be seen in Figure 1.1.

Figure 1.1: Links of metrics and goals

• Resource requirements to manage the quality function. The last item in strategic planning is resources. It must be recognized and understood that a typical organization embracing the six sigma philosophy requires everyone directly involved to be appropriately trained, especially at the managerial levels. So the issues associated with resource requirements are quite important for the organization. Typical items of concern are:

  • Appropriate and applicable training.

  • Knowledgeable personnel.

  • Adequate leadership commitment.

  • Inspection and testing availability.

  • Work performance personnel.

  • Verification capability.