Static control technologies
Whenever there is static present in the environment, it can cause damage to products and even humans. Generally, one of two types of air ionization is used to dissipate the static charge – alpha or corona. Corona has been the standard for many years and is familiar to most organizations. However, alpha is slowly becoming the preferred choice for many organizations because of its flexibility, reliability, lack of maintenance, and ability to perform in environments where corona is not an option.
Historically, corona has been the most common type of ionizer used in high technology manufacturing. Corona ionizers produce ions by applying a high voltage to a single, sharp point (±5,000-20,000 V). The intense electric field at these emitter tips creates ions and expels them from the emitters. The ions are pushed by the field for ~1 mm. However, beyond that distance, the field is too weak to push the ions effectively, so it’s necessary to have an additional means of propulsion to move them to the target, like a fan or compressed air.
Because the emitter points draw dust and contaminants from the air that accumulate and eventually choke off the ionization process, Corona ionizers require regular maintenance, including cleaning and balancing. Most ionizers must also have their positive and negative HV adjusted to balance the ionizer.
Ideal uses for Corona include:
- Most applications in semiconductor packaging and testing including, plastics, carding, converting, textiles
- Applications where temperature extremes are not required and there is adequate space to fit a blower into the process
Alpha ionization uses Polonium-210, a naturally occurring radioisotope found in the soil, plants, vegetables, etc. Exceptionally effective as an ion source to neutralize static charges, Polonium-210 releases a form of energy known as alpha energy. Alpha particles collide with surrounding air molecules, creating pairs of positive and negative ions. And since only airflow is used to move the ions, no external energy source is required. Unlike Corona, alpha ionization is not limited to a single point, so it is a very effective and predictable method of ionization. Static charges are neutralized right at the source, with the ionization process remaining in constant balance.
While the question of safety always comes up with alpha, Polonium-210 poses no hazard to workers or material. It’s safely locked inside a foil in the ionizer. And since alpha energy is not capable of penetrating even paper, there is no possibility of it causing exposure from outside your body. While alpha ionizers require no maintenance or balancing like corona, they do require replacement every 12-15 months and are subject to government regulations. This practice has proven to provide improved results as it enables Alpha ionizers to function at the highest levels.
Ideal uses for Alpha include:
- Applications with temperature extremes (-40°C to 180°C)
- Areas with tight confines, like a handler
- Applications involving Class 0, highly static sensitive parts
- In fields of high technology, electronics manufacturing and testing