Description Page
SYSTEM 4 10-13
Drive-Loc VI 11
ESD Safe SYSTEM 4 Handles/Blades & Sets
Description Page
Prec. Slotted/Phillips 4-5
Prec. Torx/TorxPlus 6
Prec. Hex Screwdrivers 7
Prec. Nut Drivers 8
Ceramic Slotted/Phillips 9
ESD Safe Precision Screwdrivers
What is ESD?
Basic Concepts in Electrostatic Discharge (ESD)
We have all seen static electricity in the form of lightning or perhaps felt the
zap when reaching for a door knob. Similar types of electrical charges can have
an effect on the electronic components you handle every day in your work.
Unfortunately, their effect is much more hazardous and not as readily apparent.
Denition
Static electricity is an electrical charge at rest. Static electricity is most commonly
created by friction and separation. Friction causes heat which excites the molecular
particles of the material. When two materials are then separated, a transfer of
electrons from one material to the other may take place.
As electrons transfer, the absence or surplus of electrons creates an electrical field
known as static electricity. The simple separation of two materials, as when tape is
pulled off a roll, can also create this same transfer of electrons between materials,
generating static electrical fields.
The amount of static electricity generated depends upon the materials subjected
to friction or separation, the amount of friction or separation and the relative
humidity of the environment. Common plastic generally will create the greatest
static charge. Low humidity conditions such as those created when air is heated
during the winter will also promote the generation of significant static electrical
charges.
Materials that easily transfer electrons (or charge) between atoms are called
conductors and are said to have “free” electrons. Some examples of conductors
are metals, carbon and the human body’s sweat layer. Materials that do not easily
transfer electrons are called insulators. Some well known insulators are common
plastics, glass and air. Both conductors and insulators may become “charged” with
static electricity. When a conductor is charged, the free electrons give it the ability
to discharge rapidly when it comes close to another conductor with a different
potential.
Typical Electrostatic Voltages
Many of the common activities you perform daily may generate charges on your
body that are potentially harmful to components.
Some of these activities include:
· Walking across a carpet, 1,500 to 35,000 volts
· Walking over untreated vinyl floor, 250 to 12,000 volts
· Worker at a bench, 700 to 6,000 volts
· Vinyl envelope used for work instructions, 600 to 7,000 volts
· Picking up a common plastic bag from a bench, 1,200 to 20,000 volts
Costly Effects of ESD
When you feel a static shock, you are experiencing a minimum of 3,000 volts of
electricity.
This “shock” known as Electro Static Discharge or ESD also may be responsible
for damaging many of the rejected electronic components in your company.
While you can feel electrostatic discharges of 3,000 volts, smaller charges are
below the threshold of human sensation. Unfortunately, smaller charges can and
do damage semiconductor devices. Many of the CMOS technology components
used in your facility can be damaged by charges of less than 1,000 volts. Some of
the more sophisticated components can be damaged by charges as low as 10 volts.
You should be aware of the relative sensitivity to ESD damage of devices you may
be working with.
As electronic technology advances, electronic components tend to become smaller
and smaller. As the size of the components is reduced, so is the microscopic
spacing of insulators and circuits within them, increasing their sensitivity to ESD.
As you can predict, the need of proper ESD protection increases everyday.
Types of ESD Damage
Static damage to components can take the form of upset failures or catastrophic
failures.
· Upset failures - result in gate leakage
· Catastrophic failures - occur in two forms, Direct and Latent
Direct catastrophic failures occur when a component is damaged to the point
where it is DEAD NOW and it will never again function. This is the easiest type of
ESD damage to find since it usually can be detected during testing.
Latent failures occur when ESD weakens or wounds the component to the point
where it will still function properly during testing, but over time the wounded
component will cause poor system performance and eventually complete system
failure. Because latent failures occur after final inspection or in the hands of your
customer, the cost for repair is very high. Not only is this type of damage hard to
find, but it severely affects the reputation of your company’s product.
An upset failure occurs when an electrostatic discharge has caused a current flow
that is not significant enough to cause total failure, but in use may intermittently
result in gate leakage causing loss of software or incorrect storage of information.
Upset or latent failures may pass your company’s quality control testing program.
In other words, static damage may occur that cannot be felt, seen, or detected
through normal testing procedures.
Think of Static As Contamination!
Damage caused by invisible and undetectable events can be understood by
comparing ESD damage to medical contamination of the human body by viruses
or bacteria. Although viruses and bacteria are invisible, they can cause severe
damage even before you can detect their presence. A defense against this invisible
threat is sterilization.
As an employee, the hidden threat of electrostatic discharge or ESD should be
of great concern to you. ESD damage can significantly reduce your company’s
profitability. This may affect your profit sharing, your company’s ability to
compete in the market place and even your employment. Everyone likes to take
pride in their work, but without proper ESD controls, your best efforts may be
destroyed by static electricity that you can neither feel nor see.
This Article courtesy of Desco Industries, Inc
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