Static Eliminators / Ionizers

In warehouses that store electronic parts and films, charged ions need to be delivered quickly over a wide area to reduce static. A bar-type static eliminator can neutralise a wide area of space.

In the pulse AC method, the positive and negative voltage is applied alternately to a single electrode probe, generating ions of both polarities. In the pulse DC method, each electrode must be positive or negative. This pulse AC method performs well under all conditions as more ions are generated than in the conventional method and the ratio of positive to negative ions can be changed. By delivering ions throughout the entire room and removing the electrostatic charge from airborne particles, the ionizer can prevent them from being attracted to surfaces. Also, using a bar-type ionizer in front of the entrance to a static-free site can prevent static charge and particles from being brought in by operators.

Using a dust collector in a process that transfers electronic parts can make sheets and films flutter because of the vacuum. In addition, the air may cause small, light electronic parts to be blown away. Ionizers that do not use blowers can eliminate static charges without unwanted excess air.

Non-blower type ionizers remove static charges from delicate parts that are sensitive to dust and wind pressure without using air. For example, an airless ionizer can remove static charge from thin sheets and films without making them flutter. This allows fine parts to be neutralised without being affected by wind. The efficient delivery of ions to target objects helps the elimination of static electricity over a wide area even without the use of supplied air. Even compact, space-saving spot types can airlessly remove the static charges.

The anti-static method of blowing off dust can generate static charge and cause dust to stick to surfaces again. Using ionizers for static elimination can also remove dust. This can neutralise products and prevent dust from re-adhering once static elimination takes place.

Ionizers that remove dust by high-pressure air purges remove dust and static electricity at the same time. Static is eliminated when dust is blown off, neutralising the target object and preventing re-adherence. These ionizers can be attached to conveyor systems for static elimination and dust removal of products during transfer as well as be used at entrances to cleanrooms.

Before people or objects enter a room, air shower equipment removes dust from the surfaces using an air jet purified by a HEPA filter. However, if clothes and dust are charged, the blown-off dust can reattach itself to the surfaces. This is because air showers cannot eliminate static electricity. They can increase charge, and do not completely remove dust and dirt. In such cases, ionizers should be used to blow off dust and dirt with ionized air. With no re-adherence, contamination caused by dust and dirt can be significantly reduced.

When formed products are charged by friction inside the mould, they may stick to the mould and not come out. Smaller, thinner formed plastics are light and stick more easily to surfaces. Combined with the increased complexity of the shape, the larger interface surface with the mould makes them prone to charging. High-speed moulding machines can have a higher level of static buildup due to their rapid injections, which consequently increases the risk of residual products in moulds. While preventive action such as using a cover may be considered for particulate-induced defects, it is not effective for reducing static. Similarly, installing sensors can be considered in order to deal with residual products in mould, but sensors can only detect products remaining in the mould and still need human hands to remove them, causing frequent stops and longer time in production. Ionizers can eliminate static charges and prevent particle adhesion and residual products in the mould, which is useful for reducing wasted materials and improving manufacturing yield.

Camera parts can accumulate a charge from friction and peeling during assembly. Dust and particles are attracted and adhere to charged parts. Dirty parts go to the next process and bring dirt inside cameras. This is caused by insufficient static elimination. Not being able to confirm static elimination is another issue. Some static eliminators have a “visualising light” for showing electrostatic levels. With these static eliminators, it is possible to instantly determine whether the static on the target object has been properly eliminated, making operation checks during startup easy. Effective particle control can be put in place while verifying the effects. It can also save workers from having to remove and clean out dirt and particles that were not removed.

How particles adhere to surfaces depends on whether the surface is conductive or non-conductive. In either case, an ionizer can be used for prevention. If the surface is plastic or rubber, or any other kind of non-conductive material, and the location of static buildup is known, particle adhesion can be prevented by localised static elimination. On the other hand, with conductive surfaces, the particles themselves can be neutralised to prevent adhesion. A bar-type static eliminator can be used for a large space where airborne particles are present to eliminate static from the entire room. In this case, removing the electrostatic charge from airborne particles can prevent them from being attracted to surfaces.

Humans constantly accumulate charge when moving. A bar-type static eliminator can be used for a large space where airborne particles are present to eliminate static from the entire room. To eliminate static from large spaces, the neutralising ions must be carried long distances. Some ionizers can have different cycles (frequencies) to generate positive and negative ions. Lower frequencies make for a longer emission time of ions of the same polarity, which makes them repel each other and spread wider. In contrast, higher frequencies switch positive and negative ions rapidly, which causes like ions to be attracted to each other and prevents them from travelling any significant distance. The frequency should be set lower for static elimination for large spaces.

Problems in transfer processes can vary, including incoherent pass-over timing, friction or suction on object surfaces, chemical affinity, magnetic force and static buildup. Among such factors, static electricity tends to be a common culprit for transfer trouble at manufacturing sites. Such problems can be solved by making the Coulomb force―be it attractive or repulsive―disappear, which specifically means to remove the static charge. For example, in case of a problem of sheets sticking to a roller, an ionizer should be aimed at the point where the sheet leaves the roller. In another example where parts from a part feeder lift up and do not flow well on the conveyor, an ionizer should be aimed at a point between the rail and parts for static elimination.

Electrostatic discharge can destroy electronic parts. This problem occurs when the accumulated electrostatic charge is discharged and causes a larger current than normal to flow in the circuits, generating heat that destroys the electronic part. The three key points in preventing ESD damage are: suppressing electrostatic generation, eliminating static buildup and preventing electrostatic discharge. The specific solutions to these problems are grounding, adding conductivity and static elimination (ionizers). Notably, ionizers can be useful when grounding is unavailable. Damage to electronic parts can also be caused by electrostatic charge accumulated by the electronic part itself and discharging it elsewhere, causing destruction inside the electronic device. In such cases, the parts themselves must be neutralised, a task for which ionizers are effective.

Where static electricity is discharged, there is always electromagnetic noise. This electromagnetic noise can cause malfunctions in electronic equipment and devices. With such a malfunction, the problem is not the amount of electrostatic charge, but rather the electromagnetic noise generated the when the electrostatic charge is discharged. This means that it is important to prevent electrostatic discharge and electromagnetic noise generation. Specifically, grounding and static elimination (ionizers) can be used for these problems. For example, on a can manufacturing line, charged cans can discharge static, generating electromagnetic noise that ends up stopping the system. A static eliminator (ionizer) is used to prevent such malfunctions. As static eliminators (ionizers) can eliminate static without coming into contact with products, it is easy to add them onto existing production lines.

Application and marking problems are sometimes caused by forces described in Coulomb's Law. If the material to be painted is negatively charged before the application process, it is possible the paint, sealant, or whatever is to be applied, will be repelled. This is due to Coulomb's Law. Application and marking problems can be solved by making the Coulomb force disappear; more specifically, using an ionizer to remove the static charge. An ionizer used to prevent an application or marking problems can be installed so that the ionizer focuses on the intended area. A nozzle-type ionizer is suitable for installing in such narrow spaces.

The two commonly known causes of static electricity generation are:
• Objects rubbing against each other (friction)
• Peeling off closely bonded objects (peeling)
Basically, static electricity is generated when objects come into contact and there is a transfer of electrons. Static electricity generated by friction is part of static charge caused by contact and movement. Static electricity caused by peeling off closely bonded objects is caused by the removal of electrons. However, static electricity generated by friction is usually greater than that caused by peeling due to the rubbing at the interface increasing contact surface and the temperature rise in the surfaces caused by friction.

Dust and particle adherence to metal objects (conductive objects) is caused by charged dust and particles coming near the object and producing electrostatic induction inside the object. Electrostatic induction can also occur when an object is grounded and therefore taking direct anti-static measures for metal objects is not effective. For the above reason, it is important that you take anti-static measures against clinging dust and particles. However, static elimination of airborne dust and particles in the open air is realistically impossible. Therefore, the general way to do this is to neutralise the entire space, or in other words, create an environment that can be constantly be neutralised.

Usually, static mats, static flooring, grounding cables, or other methods are used to control static electricity while on the table or bench. As the PCBs leave the bench or table and are transferred into the plastic parts, static elimination can be performed. Ionization during the transfer is an effective method. Eliminating static from the entire room is the most effective for preventing ESD damage. Using an ionizer is one way to eliminate static from the environment.