How are ESD plastics made?
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Conductivity Is Imparted To
Plastics By Compounding One Or More Of The Following Additives Into The Plastic
Powdered Metals:
Gold, Silver, Copper, Aluminum, Zinc, Nickel
Powdered Carbon:
Carbon Black, Graphite - Materials Have Both Surface And Volume Conductivity
Carbon Loaded Materials Have Permanent Conductivity
Carbon Is A Low Cost Additive
It Is Difficult To Produce Plastics That Are In The
Dissipative
Range: E6 Ohms To E9 Ohms
Nano Tubes:
These are vapor-grown carbon nano-tubes and nano-fibers
Antistats:
ETHOXYLATED AMIDO Amines
Inherently Conductive Polymers:
Polyether Amides, Polyether Amides, Polyanilines
ICP’S Have Both Surface And Volume Conductivity.
ICP’S Can Not Be Used Alone. They Must Be Compounded With
Other Plastics To Achieve Good Mechanical Properties.
ICP’S Give Resistance Values In The Static Dissipative Range.
E2 Ohms To E4 Ohms
Inherently Dissipative Polymers:
Polyether Amides, Polyether Amides, Polyanilines
IDP’S Have Both Surface And Volume Conductivity.
IDP’S Can Not Be Used Alone. They Must Be Compounded With
Other Plastics To Achieve Good Mechanical Properties.
IDP’S Give Resistance Values In The Static Dissipative Range.
E6 Ohms To E10 Ohms
Metal Oxide Semi-conductors:
Tin Oxide, Vanadium Oxide, Indium Tin Oxide
Poorly designed systems with the wrong materials can generate
several volts/cm peak and over 500 v/cm to the control PCBA’s. Molded insulating
polymer materials, while typically attractive by being less expensive than
machined metal parts, can increase the hazards of ESD by increasing the
resistance of or obstructing ground paths. It should be noted, great care must
be taken when selecting materials. Insulating polymers also typically increase
triboelectric charging. Don’t reley only on initial costs.
What to do next from here...
Examine and write a short 1 page report on each of the
following topics.
Team Meeting
Use separate pieces of paper
for each one topic. Hang on wall 3 feet apart. Get post it pads in a
meeting with the different team members. Each one of the team members
write down on the large post it ...what is important to the project for each
listed topics. Combine each post it pad under the general topic subject.
Examine list and remove repeats, and not related words. Give the writer a chance
to explain if necessary. Often, that word may not be the right choice and
the team will find common ground under another word. On the topic index
papers hanging on the wall, write down the agreed upon word that was on the post
it pad sheet. Combine words a sentence which describes the needs and
functions based on the post it pads.
Understanding:
Current applications
Current product sensitivity
Considering:
Shrinking form factors and new models
More complex technologies that are on the table
Determining:
Ability to operate with a trained work force in an ESD
safe material compliant work zone.
New Applications
Summary Of Material Options
Device Limits
Economic Benefits
