Reason for static Control static can cause several problems in a production facility.
In the film, extrusion for static can cause edges to curl and jam machinery.
In injection molding, the problem tends to be the attraction of dirt caused by static charge onto the part. Thus, creating painting and packaging issues.
Today there are many ways to eliminate the static buildup on parts. More powerful AC static bars and DC systems that can work farther away from the target product eliminating static charge. Neither requires any air.
Small packaged blower systems with air can assist in static control for very slow-moving production. Because introducing blower air, tends to be turbulent. The “ions,” pushing further, also re-combine. Especially as the distance grows if the target moves too fast,. There is insufficient time to eliminate the static simply because the ion concentration weakens.
Using the laminar flow of a compressed air-operated air knife or an annular air amplifier will push the “ions,.” Their re-combination will slow, but it still will weaken over distance.
So it should be with great caution when you come across claims of removing static from a target many feet away. Specifically when no time frame is specified, as the time needed can be quite long.
Even a static bar with no air behind it, several feet from a highly charged target, will still remove the static “given enough time” – again, a long time.
And in any production line, that exposure time is severely limited for obvious reasons.
Reason for Static Control With Air Suggested Products
If the distance is significantly considerable from the target or the static charge is exceptionally high on the target, the only way to remove the static and clean the part of dust and debris in a production line is to use a fixed bar or pin ionizer strong enough.
Providing a firm Ion Pin with their Ion Blaster Beam being mounted to a plastic attachment. By avoiding grounding, which can weaken the static elimination pin.
They have a standard and an extra strong static bar (which produces more ions for static elimination when dealing with a fast-moving and highly charged target) with their Ion Air Blade Ionizers.
When considering static elimination, try to avoid using air, especially if the purpose is solely for removing static charge, even if you cannot get close to the target.
But if cleaning is necessary, then an air source,, will be required with the static-eliminating device.
But do not get fooled that air alone, no matter what the source, will extend the range of the static eliminating “ions” without weakening the effect, thereby extending the time necessary for exposure to remove the static charge.
The only effective way to ensure static removal is cleaning from a distance. With a stronger concentration of static elimination ions.
Nex Flow offers additional consultationin using air with static and can advise on the optimal solution for your facility.
Static electricity is an imbalance between positive and negative charges in materials. Most people have experienced it in everyday life whether it be with their laundry being “clingy,” making a balloon stick to a wall after rubbing it on your clothes, or when walking with socks on the carpet and getting a small shock from the doorknob. All objects are made up of atoms which have positive and negative charges, like charges repel each other (positive-positive, or negative-negative), while opposite attract each other (positive-negative).
Static attraction and Repulsion
Static electricity is a result of an imbalance between positive and negative charges when two objects or materials come into contact. The surface electrons (charges near the surface of the object) try to balance each other while the two surfaces are together. Let’s say there’s object A and object B. When object A and object B are touching, “A” gives up electrons and becomes more positively charged while “B” collects the extra electrons and becomes more negatively charged. When the two materials are separated, an imbalance occurs with the surface of “B” having a surplus of electrons and the surface of “A” having a shortage of electrons. These charges build up when they don’t have a direct path to the ground, and can eventually build up enough to cause a spark to a nearby grounded or less charged object in an attempt to balance the charge.
In various industries – this can cause issues with static charge knocking out sensitive electronics near the statically charged area, cause curling in plastic web processes that can cause jamming of machinery, or charged materials attracting dirt causing cleanliness issues in packaging, coating and painting operations. It can also be a nuisance and even a danger to personnel if being subjected constantly to static charges, especially if the charges are high.
Static charge is best eliminated just before the problem created by the plastic occurs. For example, if the problem is dirt on a part, it is best to eliminate the static “before” the dirt is attracted to the part. Sometimes it is not always possible to do that in which case the dust must then be removed. In such cases you can use an anti-static devices coupled with a compressed air operated air knife or air amplifier (ionizer bar in the case of an air knife and spot ionizer in the case of on amplifier). These products “ionizes” the air from the blow off units that bombard the statically charged surface with alternating positive and negative ions, which combines with the opposite charge on the surface of the part thereby eliminating the static charge. This makes it easier to blow off the dust. Nex Flow examples would be the Air Blade Ionizer and the Ion Blaster Beam. Normally dust can be blown off but if sticky, the force may not be enough and wiping may be necessary. Blower systems can also blow off dust but they need much higher volume and stronger ionizing systems due to turbulence. (Compressed air systems provides laminar flow and work better with ionizers).
When the problem is not dirt, and the anti-static device can be close to the problem area, no blow off or air is needed, only the anti-static device itself. Today the most common static removal technology is still AC technology. Normally, these static removing devices need to be very close to the part unless air is supplied which allows it to be a bit further away (and of course can also clean). Nex Flow also has an extra powerful AC ionizer for longer distance mounting and also if the static charge is extremely high for better static elimination. There are also now DC systems which operate farther away than AC systems from the target. They are also effective in blow off and cleaning of statically charged parts.
Two measurement devices are important when trying to control static electricity. One is a voltage measuring device such as the Multicheck which indicates if there is adequate voltage at the “pins” on the ionizer which generate the static removing ions. This will confirm if the static removal system is working. If the voltage is below the normal level it could be from either dirt buildup on the device and cleaning is necessary or there is damage somewhere in the system. The other is a static meter. Nex Flow has a lower cost and a more accurate higher cost version depending on the needs of the particular application. The static meters measure the static charge on the part before and after application of the static removal action. This will indicate if the system works as required.
Nex Flow has many years of experience in static control and can address any application where static may be causing issues in production, safety and/or cleanliness.
Static can be a major problem in manufacturing processes involving plastic. When producing, cutting or plastic materials and other types of insulating materials, static charge can build up. Even metals and conductive materials can have issues with dust and dirt (normally insulating materials). The issue is often because when these material has static charges, particulates like dirt will adhere to the surface of the object and become very difficult to remove.
One area of expertise for Nex Flow is the cleaning of material that may be statically charged or having to address dirt issues. Our product was recruited by a factory in Thailand for a very interesting application with plastic pipes. Despite the fact that South East Asia is a rather hot and often humid environment for much of the year, static can still build up and cause issues.
With the plastic pipe, the pipe is extruded and then cut. After cutting – small pieces of plastic waste generated from the cut “stick” to the inner walls of the pipe. The plastic cuttings stick primarily due to static charge and is therefore difficult to remove. At the time, our client was using an normal air gun which was tedious and time consuming to remove plastic scraps. Often the scraps were blown further into the pipe making it even more difficult to remove. Yet the pipe had to be cleaned on the inside prior to shipping.
Initially a Nex Flow 6” X-Stream Air Blade Ionizer – a 6” air knife attached to a static bar. This test was performed manually simply by holding the Air Blade Ionizer at one end of the pipe and blowing into the pipe towards the opposite end where the debris had built up. When the air flow from the unit was blown into one end of the pipe, despite the overall length being extremely long (several meters) the laminar flow exiting the air knife “hugged” the inside of the pipe and carried the “ionized” air flow till the opposite end where the particulate was stuck. The static eliminator bar instantly neutralized the static on the scrap that was stuck to the pipe and literally blew every single piece out that was in the path of the wide sweeping air flow. It was actually quite dramatic. The air flow covered over 50% of the inside of the pipe surface. The inside surface of the pipe is relatively smooth so the debris was not sticking due to any no other reason except static.
So while it worked in a manual test, the next step was to find a way to have this done in the production line automatically and to also have the “ionized air” cover the entire surface of the inside diameter of the piping. To meet both requirement, the Nex Flow Ion Blaster Beam was used. The device consists of a Nex Flow Model FX20 Air Amplifier that has a plastic attachment at the outlet end where “amplified” air flow exits. On this plastic attachment is an Ionizing Pin which makes an “ion cloud” that makes the air flow anti-static. This cloud of ionized air then exists the plastic attachment. The plastic is necessary because if the Pin was surrounded by metal, it will draw away too many ions through grounding, thereby weakening the ion cloud and reducing the overall effectiveness of static elimination by the time the air hits the debris at the opposite end of the pipe. The outlet air flow from the Ion Blaster Beam is conical. Just like the air knife, the air flow is laminar. Therefore when the conical air flow is blown into one end of the pipe, the flow profile of the existing air spreads and covers the entire inside diameter, then “hugs” the inside diameter covering the entire inside surface of the pipe, and continues to the end of the pipe with the plastic dust and dirt and all easily blown. The result is a pipe with the inner surface fully cleaned.
At this point one industry myth that needs to be addressed is often claims that an air knife or air amplifier can always eliminate static at distances like 20 feet (6 meters) instantly. It does not happen that way. As the ions, a mixture of positive and negative charges, travel with the air flow, some will recombine along the way. The weaker this “mixture” is, the more time it will take to reduce or eliminate static charges. If the static charge is high, or the target for removal of static is fast moving, a strong ionizing bar or pin would be needed. Nex Flow has stronger static technology available for such situations. The plastic attachment used in the Ion Blaster Beam, as well as a powerful ionizing pin, results in the speed of static elimination to be up to 30% faster than an air amplifier system that uses a metal attachment. This is significant in high speed or highly static applications. Learn more about static elimination here!
The Nex Flow Ion Blaster Beam comes with, so it can be easily mounted on the customer’s pipe processing machine. As the pipe is cut, it rolls in front of the Ion Blaster Beam, which is placed at the end of the pipe. Then the unit is turned on for a few seconds cleaning out the inside of the pipe. Regardless of which end it is placed, the air flow is powerful enough to remove all debris. The force can also be controlled with a pressure regulator. If the unit, for whatever reason requires more force, the air amplifier that comprises the Ion Blaster Beam has a gap controlled by a shim that can be opened to add more shims. Compressed air is conserved because it is only used for a short blast in every cleaning cycle. Overall very little energy is needed. After the cleaning blast, the pipe is rolled out of the way and a new one replaces it then the cleaning cycle repeats.
The Ion Blaster Beam was a very simple solution to eliminated the time needed to manually clean the pipes along with significantly improving the quality. It was easily installed and requires little maintenance (occasional cleaning of the ion pin), and was able to assure that the compressed air is clean and dry with proper filtration.
Both the Nex Flow Air Blade Ionizer and the Ion Blaster Beam are excellent for cleaning statically charged parts. Not just because they have good ionized air but because of the even coverage of the surface impinged upon by the ionized air. This air knife’s continuous gap (continuous flow) is what you do not get when using perhaps rows of nozzles or drilled pipe and the conical shape of the airflow from the amplifier with an ionizing pin covers a wider area evenly. Unlike what a few small holes can accomplish placed around an ionizing pin. So for class A surfaces in particular like you get in the automotive industry, such applications are much better suited for using air amplification technology along with quality static elimination technology.
Plastics, glass and other insulating materials generate a static charge when rubbed, cut, and stretched. Hot or warm plastics will generate a static charge as they cool. In many production processes this can cause any of the following problems:
Static charge will attract dirt particles. If the part needs to stay clean for further processing such as painting, coating or even just packaging, these particulates can be a major issue.
As the product moves along the manufacturing process, materials such as film may bend or warp due to static and cause jamming of machinery, and hence downtime.
If the static charge is high enough, it can cause sparks and discomfort or even harm to personnel working with the material that is statically charged.
For these reasons, static charge needs to be eliminated or at least reduced and controlled. So how does the static charge get generated in the first place? Static electricity is the result of an imbalance between negative and positive charges in an object. These charges can build up on the surface of an object until they find a way to be released or discharged.
The rubbing of certain materials against one another can transfer negative charges, or electrons. For example, if you rub your shoe on the carpet, your body collects extra electrons. The electrons cling to your body until they can be released. As you reach and touch your pet (which is being really mean!) or perhaps a door knob, you get a shock. This same process occurs in a production line.
There are two ways to address a static charge. One is with a passive static eliminator and the other is with an active static eliminator.
Passive Static Eliminator
Some Passive static eliminator examples include: Copper Tinsel, Nylon Brushes, Sharp Edged Metal Strips, Antistatic Flexible Rope and Anti-Static Spray. These passive devices usually only reduce the charge with the exception of antistatic spray. In some situations – a reduction in the static charge may be adequate, however there are limitation with these passive devices. For rope and tinsel, it can potentially be dangerous when they break off and also has the potential to fall onto the material being processed. Antistatic spray may not be used if the statically charged part cannot tolerate a liquid for any reason. Brushes are limited to slow moving and lower static charges – most commonly used with printers, fax machines, and elsewhere where static only needs to be reduced to avoid sticking of the sheets.
Using passive static control may help in preventing some machine jamming and address employee discomfort but because it does not eliminate static completely (except for antistatic spray) it will usually not be enough to address dirt problems caused by static. Sprays have the disadvantage of being an endless consumable and an on-going cost that can add up over time. If the charge is very high, a passive device may knock the charge down to an extent but still leave a very high static charge that needs to be further addressed. This is when active static elimination is needed.
Active Static Eliminator
Active static eliminators (static bars or ionizing bars) are electrically operated and can be either AC or DC systems. DC systems are designed to work farther away from the target but are usually more costly than AC systems. On the other hand, AC systems normally work close to the statically charged product to remove the static charges. That being said – a more powerful AC system such as the Haug VS bar offered by Nex Flow is available which works at a further distance depending on the speed of the target. Active systems essentially ionize the oxygen molecules of the surrounding air which get attracted to the charged surface, thereby neutralizing the charge that the air “sees” (come in contact with).
Active systems work by generating alternatively a negative and then a positive charged ion. Whatever the charge on the surface is, the oppositely charged ion will remove it. Active systems can remove almost, if not all the static charge from the surface of a statically charged part. There needs to be an adequate number of ions for the level of charge needed to be addressed as well as some dwell time over the charged area. The faster the target moves the less dwell time is available for the static eliminating ion to remove the static charges. So for fast moving materials, you need a more powerful static bar – either high powered AC system or a powerful DC bar. Keep in mind that the distance from the target also matters. The further the bar is positioned, the longer it takes for the ions produced to arrive at the target and as they travel some will recombine. The result is less concentrated eliminating ions reaching the target surface.
Combining an Air Knife to a Static Bar
One way to help make a static bar work further away is to push the ions with either low pressure compressed air or with blower air. There is a myth perpetrated by some companies that make air knives, claiming that you can remove static charge at a ridiculously large distance just by adding a compressed air operated air knife. This is not entirely accurate. It is true that compressed air operated air knife, being laminar will push the ions and have much less of a recombination of ions than pushing these ions with a turbulent flow, but some recombination will still occur. So the further away the static eliminator bar is placed from a statically charged target, more dwell time will be needed to remove the static charge.
The only way to address a very high static charge or a fast moving target at a great distance from the target is with a stronger static bar that produces more ions – not by just using a compressed air operated air knife. History has proven this. If a static bar works at a moderate distance to the statically charged surface, it will probably still work if the static bar is combined with an air knife, on a moderately charged surface and at moderate speed. But to truly eliminate static charge farther away or at high speed, you actually need a stronger AC bar or a DC bar, with or without an air knife.
The real purpose of an air knife, whether blower operated or compressed air operated is to clean the parts. Dirt particles that stick due to static charge cannot be blown off easily because they get attracted back to the surface, even if loosened by a blast of air. By combining a compressed air knife with a static bar (ion air knife), the ions that get pushed by the laminar air flow eliminate the static charge allowing the static particles to be easily removed. Once the static charge is gone, it takes very little energy to remove the particles, so the air pressure can be as low as 2 – 3 PSIG in many cases. Blowers combined with static bars also work but because of the nature of the air flow with blowers, they need stronger or double static bars to do the same job and should have a high mass flow. In many instances, if the air flow is intermittently used, the energy cost of a compressed air knife static systems to blower air knife static systems are about the same. The advantage of a compressed air versions is that it is much quieter, simpler, compact, and is less costly to install and maintain. Nex Flow offers compressed air operated air knife systems with standard as well as with extra powerful static bars.
Combining an Air Amplifier to a Static Bar
Another version combining compressed air with static control is using an annular compressed air amplifier with a point ionizer (spot ionizer). This produces a laminar cone of ionized compressed air to blow onto the charged surface. Some applications include neutralizing the inside of blow molded or injection molded containers to loosen and remove plastic pieces and strings inside due to cutting processes. Another application is to blow off plastic strings and pieces after a molding process form the mold itself. Again, all these particles stick due to static charge. Our Ion Blaster Beam is a point ionizer attached to a compressed air amplifier via a plastic attachment. The attachment should be plastic to avoid the grounding effect of metal that would reduce the effectiveness of the ions generated. This is one of the reason why our Ion Blaster Beam works up to 30% faster than competitive units of similar design but with metal attachment.
Manual Static Elimination
For manual static elimination, an anti-static air gun is best and for the same reason stated above. Dirt particles are not easily removed if they stick to the surface due to static. Only by removing the static charge can a surface be cleaned. As with air knives and with the annular amplifiers combined with a static eliminator, once the air from an anti-static air gun neutralizes the charge on the part, particles can be blown off with minimal pressure and minimal compressed air consumption.
In summary
There are passive and active static control systems. Active static control is the only means to eliminate static charge completely and not adversely affect the end product. If the static elimination system is far from the statically charged target, or if the target is fast moving, or has a very high static charge, you need to use a more powerful static eliminator or increase dwell time.
The main application for using compressed air knives and amplifiers with static eliminators is more so for cleaning the charged surface and less so for pushing the static eliminating ions. That said, compressed air knives and amplifiers with static eliminators can be used at very low pressures and, especially when used with on-off control the energy cost is comparable to using blower systems. The advantage is that compressed air operated static eliminators are low cost, compact, quiet, simple and easy to use with minimal maintenance.
For manual cleaning operations an anti-static air gun is ideal and can save a great deal of energy because you can clean with less pressure than using the air gun solely.
