Failure Modes and Effects Analysis (FMEA) 1.ppt

1

Failure Mode & Effect Analysis (FMEA)

2

Introduction

Failure mode and effects analysis (FMEA) is a popular tool for reliability and failure-mode analysis. To cover both design and production, FMEA should include the activities at both design and manufacturing stages. It is common and critical to conduct reliability analysis at the earliest stage of the product life cycle. Design and product engineers need to work with a project team that at least includes customers, reliability engineers and manufacturing engineers to identify the potential quality and reliability failures in the design process.

Sheng-Hsien (Gary) Teng, Shin-Yann (Michael) Ho. Failure mode and effects analysis: An integrated approach for product design and process control.

International Journal of Quality & Reliability ManagementVolume 13 Number 5 1996 pp. 8-26.

3

Failure mode and effects analysis (FMEA) is an analytical technique (a paper test) test that combines the technology and experience of people in identifying foreseeable failure modes of a product or process and planning for it elimination. In other words, FMEA can be explained as a group of activities intended to

i. Recognize and evaluate the potential failure of a product or process and its effects.

ii. Identify actions that could eliminate or reduce the chance of potential failures.

iii. Document the process.

Dale H. Besterfield, Carol Besterfield-Minhna,Gien H. Besterfield & Mary Besterfield-Sacre,Total Quality Management, 3rd Edition, Prentice Hall, 2003.

4

Type ofFMEA

Design

Process

Equipment

Concept

Service

System

Environmental

5

FMEA TeamThe FMEA methodology is a team effort where the responsible engineer involves assembly, manufacturing, materials, quality, service, supplier, and the next customer (whether internal or external).

Team leader responsibility:

1. Determining the meeting time & place2. Communicating with the rest of the team3. Coordinating corrective action assignments and follow-up4. Keeping files and records of FMEA forms5. Leading the team through completion of the forms6. Keeping the process moving7. Drawing everyone into participation

6

FMEA Documentation

3. Block diagram

1. Customer needs and wants

4. FMEA Form

2. The design or process intent

7

BLOCK DIAGRAM

To understand the input to the block, the function of the block, and the output of the design.

Steps:

1. List all of the components of the system, the functions and the means of connection or attachment between components.

2. Placing the components of the system in blocks with the functional relationships which represented by a line.

BLOCK A BLOCK BCONNECTION LINE

8

EXAMPLE OF A BLOCK DIAGRAMPRODUCT: REMOTE CONTROL

9

Design FMEA

10

EIGHT (8) steps of FMEA

11

1. Identify the system to be analyzed. Divide the system into subsystems and /or assemblies in order to localize the search for components and develop a list of components for each assembly.

2. Construct the block diagram of the system. Use structural, (hardware), functional, combined, master logic diagram and cause and effect diagram to identify relations among components.

3. Determine all potential failure modes of each component, their causes and the effects of failure modes on the immediate function or item, on sub-systems and the entire system.

4. Evaluate each failure mode in terms of worst potential consequence (severity).

5. Identify failure detection methods and compensating provision(s) for each failure mode.

6. Estimate the probability of occurrence (Sf) using both qualitative and quantitative techniques.

7. Calculate the risk priority number (RPN), using relation RPN=S f.S. Sd.

8. Determine whether corrective action is required or not depending upon the RPN. If required than identify corrective design or other actions required to eliminate the causes of failure. The actions may be:

Compensatory to minimize the loss in event of failure occurrence. Preventive to avoid a failure situation.

12

Design FMEA

13

14

15

16

17

18

Question & Answer