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Design FMEA

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Definition and Purpose

Design FMEA helps eliminate design-related failures, i.e., failures due to inadequate strength, inappropriate material, and so on. A design FMEA is a structured procedure for identifying and eliminating design-related failure modes, i.e., failures due to inadequate strength, inapproprate material, and so on.

The purpose of a design FMEA is to

• Determine whether a product design is adequate for the application
• Reduce the number of design-related failure modes experienced by the customer

Benefits

Design FMEA increases customer satisfaction, resulting in improved repuatation and increased sales. It also reduces the need for engineering changes, thus reducing the length and cost of the product development cycle.


Key Elements

• Timeliness - A design FMEA must be done early in the product development cycle: after the conceptual design is decided, but before tooling begins.
• Teamwork - A design FMEA should be performed by a team of individuals representing key areas of product development, such as:
  • Product design
  • Reliability
  • Manufacturing
  • Quality control
  • Sales and marketing
  • Purchasing
  • Customer service
  • Technical support
  • Suppliers
  • Customers
• Documentation - The results of a design FMEA should be recorded on a design FMEA form and the form updated as needed throughout the life of the product.

Basic Steps

Draft Stage - The design engineer uses his/her knowledge of the product, as well as input from individuals in other areas of product development, to draft the following portions of the FMEA form:

• Functions(s) & Specification
• Potential Failure Mode(s)
• Potential Effects of Failure Mode(s) on End Product and End User
• Potential Causes of Failure
• In-Place and Planned Cause Preventions or Detections

Team review stage

• The design engineer submits the draft to the FMEA facilitator. The FMEA facilitator organizes a review team and provides them with copies of the draft, as well as engineering drawings; test results; charts for ranking severity, likelihood and effectiveness; and other supporting documentation.
• Working independently or in small groups, team members review the form and:
  • Identify additional failure modes, effects, causes, and prevention or detection methods
  • Recommend corrective actions to eliminate the cause, or to enhance the prevention or detection methods
  • Rank severity, likelihood and effectiveness
• Team members then submit their revised drafts to the FMEA facilitator, who:
  • Adds their comments to the original FMEA form to create a composite.
  • Averages the rankings for severity, likelihood and effectiveness.
  • Calculates a Risk Priority Number for each potential failure mode.
  • Distributes copies of the composite FMEA form back to team members.

FMEA meeting stage

• The team meets to:
  • Discuss the composite FMEA form
  • Reach a consensus on the Risk Priority Numbers and recommended corrective actions
  • Assign responsibility for implementing the corrective actions
• The FMEA facilitator
  • Revises the composite form to reflect the outcome of the meeting.
  • Prepares a Resulting Actions form and distributes it to individuals assigned responsibility for corrective actions

Implementation stage

• The design engineer follows up on corrective actions and reports any progress to the FMEA facilitator.
• The FMEA facilitator updates the composite form.