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broken down into ions of both positive and negative charges. (An ion is an atom or
molecule which is electrically unbalanced.).The generated positive and negative
ions interact with a static laden surface in such a fashion as to reduce or completely
neutralize the static charge by returning the static charges to electrical balance.
This method is the most effective static control available, while also the most costly.
And lastly one must not forget static exists everywhere! It's the level of the static
charge that is important
Extrusions :
Contact and separation is probably the most common cause of static in industry
where film and sheet are being processed. It happens when material unwinds or
passes over a roller. When the material touches the roller a small charge flows from
the material to the roller causing an imbalance. As the material leaves the roller the
voltage is magnified like the separating plates of a capacitor. The size of the
resultant voltage is limited in practice by the breakdown strength of the surrounding
materials, surface conduction etc. You often hear small cracks, or static discharges,
as the material leaves the roller. This is where the static has reached the breakdown
strength of the surrounding air. Sharp changes in moisture or temperature also
induce static charge. The static problem will show itself in the form of a spark,
electrostatic repulsion/attraction, dust (dirt) particles accumulating on the roll can
indicate the presence of static or shocks to operators. Most typically seen problems
are: patches flying, materials won't cut, poor quality or just bad production.
Injection Moulding
Small, light mouldings can stick to the face of the tool due to static charge. This can
result in:
1. Mould damage
2. Crushed parts
3. Slower production speeds
Blow Moulding : As molten plastic parisons drop toward an open tool, high static
charges cause the following problems:
1. Mulitple parisons will repel each other
2. Single parisons will attract to the tool
Roto Moulding : Large mouldings such as rubbish bins, plastic lawn furniture, toys,
plastic pallets and containers can develop very large static charges. When the tool
is removed from the part, the static charge can cause severe operator shocks and
can attract dust from long distances.
Vacuum and Thermoforming: A complete thermoform line has several static
related problem areas:
1. The unwinding of the material causes dust attraction which is later impregnated
into the thermoform.
2. As the forms exit the tool, the static charge can cause additional dust attraction or
stacking problems

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