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STATIC CONTROL AND PLASTICS INDUSTRY
Problems with static electricity in the plastics industries are numerous. Processes
where static charge can be an issue include injection moulding, blow moulding,
thermoforming, rotational moulding, parts conveying and collection and assembly
processes. The primary problems resulting from high levels of static charge are:
Dust Attraction & Contamination: Dust and particulates attracted by the static
charge on the part can result in high and expensive scrap rates. This is especially the
case if the material is to be used in the medical or food packaging industries, or in the
painting of automotive or white goods.
Process Control & Quality Problems: Static can force companies to run their
machines at much slower speeds as it creates production problems such as parts
sticking to each other in the conveying process, resulting in jams or product
misbehaviour. It causes high reject rates and less efficient production which cannot
be tolerate.
Operator Shocks & Safety: Operator handling charged objects and materials such
as a winding reel of film and is wearing insulative shoes his/her body may get
charged by induction and charge stays in the operator's body until he/she touches an
earthed part of the machinery. Then the charge will zap to earth giving the operator a
shock. Static shocks to operators are not usually dangerous, but are certainly
unpleasant and can cause secondary reactions like there can be a moment of
disorientation, bringing with it subsequent hazards such as collision with other
operators and/or machinery. A real danger exists in the coating, printing and other
industries using combustible materials, where a static discharge can cause a fire or
explosion.
Damage to Electronics: Static discharges cause failure of electronic components
on a large scale. This is not limited to the electronics industry - it also occurs where
sensors, check weighers, printers and similar controls are close to statically charged
materials.
Controlling Static: Placing a roll of plastic on its side, flat on a concrete floor prior to
being put on the machine will reduce the Static charge to more manageable levels.
Placing a copper wire / piece being properly grounded will reduce static in that area.
Humidification (Moisture) in the air can control static charge. However relatively high
humidity can cause rust to costly machines and equipments.
Addition of Anti Static Chemicals: Anti Static Chemicals in added in raw materials
before processing which prevents the generation, accumulation of Static Electricity.
Electrically Activated Devices: commonly referred to as Static Eliminators, are a
cost effective way to break down positive and negative ions to runable levels. It
works on corona principle. Although they don't really eliminate static they are one of
the most widely used devices to control static in any production environment.
Atomic Bombardment: Specific Gamma rays are bombarded on the surface to
eliminate the Static Electricity. Ionization is the process in which air molecules are

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