| Failure
modes
Product failures occur in a predictable pattern. There are three basic
periods during which failures occur over the life of a product, namely:
•
 |
"infant
mortality” – usually
caused by inferior manufacturing and inadequate processing. |
•
|
“useful
life mortality" - normally caused as a result of inadequate product
design. |
•
|
"wear-out"
mortality •
-traditionally
caused by inferior •
design
and/or inadequate maintenance.These can be clearly illustrated by
the "Bathtub" curve as shown. |
Failures that occur at any of these stages will cause at least some amount
of customer dissatisfaction. This can result in an excessive number of product
defects with associated warranty / reliability costs and loss of company
image. Increased cost of quality and extended development times are also
experienced. |
|
Failures
and design
Most failures have their origins at the design stages and
with this in mind, a generic risk analysis technique was developed by
NASA to minimise the risk associated with a fledgling space program.It
was conceived to be used at the early design stages to determine:
| • |
all
possible ways a product can fail to meet end expectations. |
| |
|
| •
|
how
seriously these failures
impact
the program. |
| |
|
| •
|
what
design actions should be taken to prevent these
potential
failures from
occurring
in the future.
This basic technique has since been refined and the FMEA
format
is now applied across
the
full manufacturing spectrum. |
What
is FMEA
The FMEA technique is aimed at reducing the risks associated with the
release of new products by addressing potential failure modes at the design
stages and taking appropriate remedial design action to prevent the problem
from occurring in the future.
Several different
FMEA types are now commonly used, namely:
•
•
•
•
|
Design
FMEA
Process FMEA
Equipment FMEA
Environment FMEA |
|
|
In
this way many organisations have realised considerable success through
its application by:
•
|
enhancing
quality assurance
and
reliability
|
| |
|
| •
|
initiating
an expedient problem prevention system |
| |
|
| •
|
promoting
effective communication within design teams |
| |
|
| •
|
recording
the design process
for
future programs |
Today, preservation
of proprietary knowledge through the application of the FMEA process is
essential for the reduction of program timing and costs. At the same time
it is necessary to reduce the risks often associated with accelerated
product development programs when products need to comply with world class
levels of quality.
Design verification and process controls
The timely application of the FMEA is also used to generate verification
plans for the validation of products, and process control plans to ensure
that manufacturing processes meet the requirements of the customer.
Similarly the Machinery FMEA has been effective at generating total preventative
maintenance programs.
For expert
consultation, training and facilitation in this field contact:
Lou
Travella
Design 4 Excellence
Ph/Fx: 61 3 5221 6413
EMAIL:
INFO@DESIGN4EXCELLENCE.COM.AU |
|
