FME 461 ENGINEERING DESIGN II

Failure modes Effects and Analysis (FMEA) Learning outcomes To understand the use of Failure Modes Effect Analysis (FMEA) - Engineering To learn the steps to developing FMEA To summarize the different types of FMEA To learn how to link the FMEA to delivery of quality products or processes? To review some examples of FMEA To perform a FMEA exercise

FMEA by William Goble A rather simple technique, the failure modes of each component in a given system are listed in a table, and the effect of that failure is postulated and documented. The method is systematic, effective, and detailed, although sometimes called timeconsuming and repetitive. The reason the method is so effective is every failure mode of every single component is examined. 22/1/2013

FMEA A structured approach to: Identifying the ways in which a product or process can fail Estimating risk associated with specific causes of failure Prioritising the actions that should be taken to reduce risk Evaluating design validation plan (product) or current control plan (process)

How is this relevant to the design engineer? Allows us to identify areas of design or process that most impact our customers/patients Helps us identify how and where our product, system or process is most likely to fail or is failing Pin-point product or process failures that are difficult to detect

History of the FMEA Idea was conceived in the 1940s First used in the 1960 s in the Aerospace industry during the Apollo missions In 1974, the Navy developed MIL-STD-1629 regarding the use of FMEA In the late 1970 s, the automotive industry was driven by liability costs to use FMEA litigation Later, the automotive industry saw the advantages of using this tool to reduce risks related to poor quality warranties There is an SAE standard J 1739 for conducting FMEA in design and processes

FMEA other names DFMEA - design PFMEA - Process FMECA - Criticality FMEDA Diagnostic These all mean the same and fundamentally have the same steps. 22/1/2013

Similar systems/techniques APQP advanced Product Quality planning QS 9000 automotive industry ISO9001 although it has mainly been relegated to paper pushing HAZOP Hazard and Operability Study used in the petro-chemical industry CHAZOP Control hazards Operability analysis 22/1/2013

What is failure mode? A Failure Mode is: The way in which a component, subassembly, product, input, or process could fail to perform its intended function Things that could go wrong

FMEA What Failure Modes & Effects Analysis is a methodology to evaluate failure modes and their effects in designs and in processes.

FMEA Why Methodology that facilitates process improvement Identifies and eliminates concerns early in the development of a process or design Improve internal and external customer satisfaction Focuses on prevention FMEA may be a customer requirement FMEA may be required by an applicable Quality System Standard In our case we are trying to come up with a systematic way of improving process delivery

FMEA How Team identifies potential failure modes for design functions or process requirements They assign severity to the effect of this failure mode They assign frequency of occurrence to the potential cause of failure and likelihood of detection Team calculates a Risk Priority Number by multiplying severity times frequency of occurrence times likelihood of detection Team uses ranking to focus process improvement efforts

FMEA - example

Risk definition The Oxford English Dictionary defines risk as (Exposure to) the possibility of loss, injury, or other adverse or unwelcome circumstance; a chance or situation involving such a possibility Risk consists of a hazard and the likelihood of occurrence Example Highly flammable fuel like LPG but we have reduced the risk of usage by reducing likelihood of occurrence of an explosion Occasionally we get some explosions but they occur infrequently. Hence LPG is not a risky fuel to use

Risk cont.. Example of risk management: A NASA model showing areas at high risk from impact for the International Space Station. Source: Wikipedia

When to conduct an FMEA Early in the process improvement investigation When new systems, products, and processes are being designed or introduced When existing designs or processes are being changed/improved When carry-over designs are used in new applications After a system, product, or process functions are defined, but before specific hardware is selected or released to manufacturing

Example form - revisited

Types of FMEA Design Analyzes product design before release to production, with a focus on product function Analyzes systems and subsystems in early concept and design stages Process Used to analyze service/manufacturing and assembly processes

FMEA A team tool A team approach is necessary. Team should be led by a responsible manufacturing engineer or technical person, or other similar individual familiar with FMEA. A healthcare professional with experience and familiar with the FMEA process for healthcare applications. You can invite engineers for an outsider s perspective The following should be considered for team members: Design Engineers, Operators Process Engineers Reliability Materials Suppliers Suppliers Customers

FMEA procedure 1. For each process input (start with high value inputs), determine the ways in which the input can go wrong (failure mode) 2.For each failure mode, determine effects Select a severity level for each effect 3.Identify potential causes of each failure mode Select an occurrence level for each cause 4.List current controls for each cause Select a detection level for each cause

FMEA procedure - Cont 5. Calculate the Risk Priority Number (RPN) 6. Develop recommended actions, assign responsible persons, and take actions Give priority to high RPNs MUST look at severities rated a 10 7. Assign the predicted severity, occurrence, and detection levels and compare RPNs

FMEA input and outputs

FMEA The relationship between failure modes and effects is not always 1 to 1.

Severity, Occurrence & Detection Severity Importance of the effect on customer requirements (Patient outcome) Often can t do anything about this Occurrence Frequency with which a given cause occurs and creates failure modes Detection The ability of the current control scheme to detect or prevent a given cause

Rating Scales There are a wide variety of scoring anchors, both quantitative or qualitative Two types of scales are 1-5 or 1-10 The 1-5 scale makes it easier for the teams to decide on scores The 1-10 scale allows for better precision in estimates and a wide variation in scores (most common)

Scales Severity 1 = Not Severe, 10 = Very Severe Occurrence 1 = Not Likely, 10 = Very Likely Detection 1 = Likely to Detect, 10 = Not Likely to Detect

Risk Priority Number (RPN) RPN is the product of the severity times occurrence times detection scores.

FMEA Simple Example We will conduct an FMEA on the truck stop example we used to create a C&E Matrix A Black Belt (Six Sigma Manufacturing) wants to improve customer satisfaction with the coffee served at the truck stop The process map and completed Cause and Effect (C&E) matrix follow

Truck stop coffee steps Step 1 create a process map Step 2 Cause and effect sheet A) For each input, determine the potential failure modes For each failure mode, identify effects and assign severity

Step 1- create a process map

Cause & Effect

a) Potential failure modes

b) Identify effects & Assign Severity

c) Identify potential causes for each failure mode & assign a score

d) List current controls and assign a score

e) Calculate RPN

f) Develop Recommended Actions, Assign Responsible Persons, and Take Actions

g) Assign the Predicted Severity, Occurrence, and DetectionLevels and Compare RPNs

Simple example - reactor 22/1/2013

Simple reactor FMEA 22/1/2013

Reactor continued. 22/1/2013

FMEA Exercise- leaf spring manufacturing

Severity rating 22/1/2013

Occurrence rating 22/1/2013

Detection rating 22/1/2013

Example leaf spring 22/1/2013

Application to the service industry I am involved in training medical practitioners in the use of continuous improvement tools Mccain C. (2006) Using FMEA in a service setting Quality Progress Vol 39 Issue 9 22/1/2013

Service setting 22/1/2013

Literature on FMEA There are very good sources such as Vinodh S. & Santosh D. (2012) Application of FMEA to an automotive leaf spring manufacturing organization. TQM Journal Vol 24 Issue 3 Pollack S. (2005) Create a simple framework to validate FMEA performance ASQ Six Sigma Forum magazine Vol 4 Issue 4. Reid R.D. FMEA something old, something new, Quality Progress 38 (5), 2006 James L. & Kovach J. Improving Home Healthcare Using Sigma Six,Proceeding of the 2009 Industrial Engineering Research conference

Assignment 2- Learning from failure On 29 th August 2013, Kenya lost 41 innocent people to a tragic road accident. The bus they were travelling in rolled at Ntulele near Narok, killing 35 of them on the spot. The crash occurred at 1am. Conduct an FMEA on the recent bus tragedy in the Narok region Look at the crash from an education, engineering and enforcement angle

Bus crash 22/1/2013