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Cleaner lines cleanliness and static electricity control
Higher production quality together with
increased yield demands will continue to
shape future production environments.
Understanding the experience gained by
the electronic industry in handling electro-
static sensitive products, combined with high
standards of cleanliness are critical for future
success. A basic understanding of the physi-
cal aspects is required to evaluate production
requirements and any customer specification.
Breaking through the jargon
Electrostatic discharge (ESD): A transfer of
electrostatic charge between two bodies at
different electrostatic potentials, induced by
direct contact or an electrostatic field.
Electrostatic discharge sensitive devices
(ESDS): A discrete, integrated circuit or
assembly that might be damaged by electric
fields or electrostatic discharge encountered
in routine handling, transit or testing.
Electrostatic conductive: A material with a
surface resistance of 10
2
to < 10
6
_.
Electrostatic dissipative: A material with a
surface resistance of 10
6
to < 10
12
_.
Static electricity versus cleanliness
Reduced static charges tend to reduce the
attraction of particles and dust. Preventing
relative movements will also reduce particle
generation as well as reducing static charges.
However, the criteria for creating a clean
room may not the best solution to reduce
static charges. A detailed analysis of each
production environment is required.
ESD design guidelines
It is simply not good enough just to choose
any solution which claims to be antistatic.
The concept design and materials used must
be chosen to control the ESD level as well as
ensuring a design and material usage that
ensure that particles are not generated
because of excessive wear.
In designing an ESD-protected assembly
line, it is important to ensure that the
workstation itself does not generate charges
that might damage the product.
Secondly, if a handled product that is
charged it is important to create a balanced
discharge time. A speedy discharge will
normally damage the product, but too a slow
discharge risks product damage later on.
Cleanliness guidelines
Even in an assembly line where a product is
sensitive to contamination but not to static
charges a reduced static level could be
vital in order to prevent any residual particles
from clinging to the end products.
Conductive or dissipative materials allow
the usage of more wear resistant materials
such as carbon fibre-filled polymers or mate-
rial with very low antistatic additive content.
Education and training
Operators or maintenance personnel will
always be a potential risk in any well
designed production environment.
With proper training comes the necessary
awareness and understanding of cleanliness
and static issues the route to achieving a
high-technology manufacturing or assembly
process. FlexLink can advise on precisely this
kind of training with the companys industrial
automation solutions available in both
component and turn-key form, meeting class
10 clean-room environment (US Federal
Standard 209E), low ESD volts and resistivity
values ranging from conductive to dissipative.
Cleaner production is now a goal which can
be attained and maintained.
Running Head
Tr u c k a n d C o m m e rc i a l Ve h i c l e I n t e r n a t i o n a l
1
Understanding cleanliness and static electricity control is a critical success factor for many industries.
Cleaner lines cleanliness
and static electricity control
TOMMY KARLSSON AND ANDERS PIHL
FlexLink
AUTHORS
Tommy Karlsson is sales director for
FlexLink Systems Pte Ltd, responsible for
sales and application development in Asia
Pacific. Anders Pihl is marketing manager
at FlexLink, dealing with global
business development.
The dynamic assembly system concept
in practice.
An electric measuring equipment
assembly line.
Assembly line of hard disk drives in
a clean room.