A significant challenge faced during the definition phase of Lean Six Sigma for service efforts is qualifying the value of potential process changes. Before any process improvements or new processes are introduced within an organization, it is critical to have some sense of their effectiveness. This information requires an understanding of possible failures associated with implementing the process.

The means by which potential failures may be anticipated and prepared for is Failure Mode and Effects Analysis (FMEA). Failures are defined as falling short of customer requirements. This procedure identifies possible failure modes of a process or product, frequency of failure, the effect on related items as well as the targeted function of the process or product. In addition, FMEA ranks and prioritizes causes of failure, allowing Lean Six Sigma consulting teams to develop proactive plans of action. The end result is development of a more robust process solution.

Applications for Failure Mode and Effects Analysis

FMEA may be applied to either processes or products, therefore making it applicable to both Lean Six Sigma for service and lean manufacturing Six Sigma efforts. Common uses for Failure Mode and Effects Analysis in either environment include:

  • The design of new processes
  • Rework of existing processes for better performance
  • New applications or environments for existing processes
  • As a proactive follow-up to a problem-solving study
  • Upon determination of a preliminary process understanding
  • Upon definition of system functions are defined, prior to selection of hardware
  • Upon definition of product functions, prior to design approval and release.

Types of FMEA

Failure analysis is widely applicable to a number of industries and areas within a single organization. While applications may vary, the basic principle of forecasting potential failures and creating proactive responses is a cornerstone of quality lean Six Sigma implementation.

  • Process FMEA
  • System FMEA
  • Design FMEA

Performing FMEA

This analysis is a rather straightforward process. All probable failure modes should be identified first. This could be the manner in which a product fails during use or a process fails to meet customer requirements, such as excessive delays in order processing. Past experience, performance review and brainstorming sessions are all reliable sources of this information. New processes or products lacking a history of data can be examined using proxy data from similar processes or products.

Each possible failure mode is then assigned a value between one and ten in terms of severity, occurrence probability and detection probability. These three values are then multiplied to yield a Risk Priority Number (RPN). Priorities are determined upon the value of each failure’s RPN; the greater the value, the more severe the issue.

To safeguard against failure, Lean Six Sigma efforts should include the assignment of a target RPN value.