Subject: Quality & Reliability Engineering

Topic:
Failure Mode Effects and Analysis (FMEA)
Enrollment No - 190280119065
Name - Aayush M Palodara
Division - B Batch - B2
Contents
▪ Introduction
▪ Purpose of Using FMEA
▪ Area of Application
▪ Types of FMEA
▪ Basic steps of developing FMEA
▪ Typical Format
▪ Benefits
Introduction
❑ Failure Mode and Effects Analysis, or FMEA, is a methodology aimed at
allowing organizations to anticipate failure during the design stage by
identifying all of the possible failure in a design or manufacturing process.
❑ FMEA was Developed in the 1950s, FMEA was one of the earliest structured
reliability improvement method. Today it is still a highly effective method of
lowering the possibility of failure.
❑ Failures are prioritized according to how serious their consequences are,
how frequently they occur, and how easily they can be detected.
Purpose of Using FMEA
❑ The purpose of using FMEA is to take actions to eliminate or reduce failures,
starting with the highest – priority ones.
❑ FMEA involves identifying and eliminating process failures for the purpose of
preventing an undesirable event.
❑ It is an effective in evaluating both new and existing processes and systems.
For new processes, it identifies potential bottlenecks or unintended
consequences prior to implementation.
❑ “Failure Modes” means the ways, or modes, in which something might fail.
Failures are any errors or defects, especially ones that affects the customers,
and can be potential or actual.
❑ “Effects analysis” refers to studying the consequences of those failures.
▪ FMEA includes review of the following
❑ Steps in the process
❑ Failure modes (What could go wrong?)
❑ Failure causes (Why would the failure happen?)
❑ Failure Mode and Effects Analysis (FMEA) is a structured approach to
discovering potential failures that may exist within the design of a product or
process.
❑ Failure modes are the ways in which a process can fail. Effects are the ways
that these failures can lead to waste, defects or harmful outcomes for the
customer. Failure Mode and Effects Analysis is designed to identify, prioritize
and limit these failure modes.
Area of Application
There are several times at which it makes sense to perform a Failure Mode
Effects Analysis, like as:
❑ When a process, product, or service is being designed or redesigned, after
Quality Function Deployment(QFD).
❑ When an existing process, product, or service is being applied in a new
way.
❑ Before developing control plans for a new or modified process.
❑ When improvement goals are planned for an existing process, product, or
service.
❑ Periodically throughout the life of the process, product, or service.
Major Types of FMEA
▪ There are two broad categories of FMEA, Design FMEA(DFMEA) and process
FMEA(PFMEA).
1) Design FMEA: Design FMEA (DFMEA) explores the possibility of a product
malfunctions, reduced product life, and safety and regulatory concerns
derived from:
➢ Material properties
➢ Geometry
➢ Tolerances
➢ Interfaces with other components and/or systems
➢ Engineering noise: Environments, user profile, degradation, systems
interactions.
2) Process FMEA : Process FMEA (PFMEA) discovers failures that impacts
product quality, reduces reliability of the process, customer dissatisfaction
and safety or environmental hazards derived from:
➢ Human factors
➢ Methods followed while processing
➢ Machines used
➢ Machines utilized
➢ Measurement systems impact on acceptance
➢ Environment factors on process performance.
Basic Steps to Developing FMEA
FMEA is performed in seven steps with key activities at each steps. The steps
are separated to assure that only the appropriate team members for each
step are required to be present.
The seven steps are:
▪ Step-1 : Planning and preparation
▪ Step-2 : Structure analysis
▪ Step-3 : Function analysis
▪ Step-4 : Failure analysis
▪ Step-5 : Risk analysis
▪ Step-6 : Optimization
▪ Step-7 : Results documentation.
Step 1 : Planning and preparation
➢ The FMEA study starts with a purposeful and careful definition of the scope.
The management team is responsible for setting the scope of the study. This
step involves the collection and creation of key documents.
Step 2 : Structure analysis
➢ Structure analysis is used to identify and break down the process into
sequential steps, interfaces and logistical elements. It uses the boundaries
stipulated in the definition of scope done in step 1 in order to identify each
stage, interface and logistical element in the process at hand.
➢ Structure analysis is aimed at facilitating complete understanding of the
process. Start with the central element of your scope, identify the process it is
part of and, finally, indicate all elements related directly to it.
Step 3 : Function analysis
➢ Every part of the product or of the process has a purpose. It exists because it
must fulfil requirements such that the product can work properly or that the
process operates as intended. These requirements are fulfilled by functions in
this step of the analysis.
➢ There should be an exploration of what the product should be doing in the
function analysis step, as well as of what should be executed in the general
process (and each one of its activities) and how this functionality is
facilitated. Using the structure analysis developed in step 2, each element is
analysed separately in terms of its function and corresponding requirements.
Step 4 : Failure analysis
➢ When a part of the product or of the process deviates from the function in a
significant way (or fails to perform it completely), failures are generated.
These failures are, of course, assigned to the relevant function.
Step 5 : Risk analysis
➢ Every failure cause represents a risk of the product or of the process. The
severity of the risk depends on three factors.
a) The probability of a failure cause occurring in spite of existing preventive
actions (if such actions exist).
b) The probability of a failure cause being detected with the application of
appropriate detection actions.
c) The severity of the failure effects to which the failure cause will lead (via a
failure mode).
➢ In step 5, the severity, occurrence and detection of each failure chain is
evaluated. An appropriate priority level of “high, medium or low” is obtained
based on evaluations which establish a Risk Priority Number (RPN) for actions
needed, aimed at reducing the risk of failure to function as intended.
➢ The RPM is calculated by multiplying the three rankings together.
RPM = Severity x Occurrence x Detection.
Step 6 : Optimization
➢ The primary objective of the optimization step is to develop actions that reduce risks
and increase customer satisfaction, improving the product.
➢ Most actions will likely involve lowering the likelihood of the occurrence of failure
causes or improving detection controls, either approach leads to a more robust
design.
Step 7 : Results documentation
➢ The results of each FMEA study should be fully documented. An FMEA study is not
finished until Step 7 has been completed.
Format of FMEA
Benefits of using FMEA
Discovering a failure early in Product Development (PD) using FMEA provides the
benefits of:
➢ Multiple choices for mitigating the risk.
➢ Higher capability of verification and validation of changes.
➢ Collaboration between design of the product and process.
➢ Improved Design for Manufacturing and Assembly (DFMA).
➢ Contributes to control plans and other quality assurance procedures.
➢ Lower cost solutions
➢ Legacy, tribal knowledge, and standard work utilization.
➢ Results in higher reliability and better quality.
➢ Increases safety, enhances customer satisfaction and reduce costs.