FMEA

FMEA = Failure Mode and Effect Analysis

Terminology:
  • Failure: Loss of a function under stated conditions
  • Failure mode: The way in which the components, sub -assembly, product, input, or process could fail to perform its intended function.
  • Effect Analysis: Studying the consequences of the various failure modes to determine their severity to the customer.
  • Failure Mode and Effect Analysis: is a step-by-step approach by identifying all possible failures in a design, a manufacturing or a product or a service.
Advantags:
  • Methodology that fecilitates process improvement
  • Improves internal and external customer satisfaction
  • Focusses on prevention
  • Identifies and eliminates concerns early in the development of a process or a design.
  • Occasionally, it satisfies contractual customer requirement.
  • Occasionaly, required by Quality Management System Standard, such as ISO.
Types of FMEA:
  • Design
  • Process
  • System
  • Service
  • Software
People involved in FMEA:
  • Design engineers
  • Process engineers
  • Material suppliers
  • Operators
  • Reliability engineers
  • Suppliers
  • Customers
FMEA Procedure:
  1. Determine the failure mode for each process input
  2. For each failure mode, determine effects - Select a severity level for each effect.
  3. Identify potential causes for each failure mode- Select an occurance level for each cause.
  4. List current controls for each cause- Select a detection for each cause.
  5. calculate the Risk Priority Number (RPN)
  6. Develop recommended action, assign responsible persom and take actions.
  7. Assign predicted severity, Occurance and detection levels and compare RPNs.
Calculation of RPN: \[\mathrm{RPN} = \mathrm{Severity} \times \mathrm{Occurance} \times \mathrm{Detection}\]
  • Severity is based on the effects on customer requirements, generally on a 1 (not severe) to 10 (very severe) scale.
  • Occurance is frequency with which a given cause occurs and creates failure modes, generally on a 1 (not likely) to 10 (very likely) scale.
  • Detection is based on the ability of the current control scheme to detect then prevent a given cause, generally on a 1 (easy to detect) to 10 (not easy to detect) scale.

Solved Example:

9032-01

In the context of factors utilized in FMEA, choose the odd one out. (ISRO IPRC Tech Asst Mech Apr 2018)

Correct Answer: C