If you want to print on plastic, it’s challenging – most plastics are chemically inert and non-porous. That means you can apply all the ink you want; it’s not going to stick. In the 1950’s, a Danish engineer named Verner Eisby experimented with various techniques to overcome these challenges. He found that exposing the surface to be printed on to gas flame or sparks modified the surface to improve adhesion with the ink. It did so, though, in a crude & uneven manner, leaving imperfections & inconsistencies in the printed product. He then tried applying a high frequency corona discharge in a linear array. The plasma (gas in an ionized state) generated left a homogeneously treated surface on which to print, smoothly & evenly.
This has become the “industry standard” for many of the labels we see on commercial products, from shampoo & wine bottles on the grocery store shelf, to pennants & banners at public events. It also leaves the surface even more prone to picking up a static charge from rolling or unrolling, stacking, sliding, etc.
One of our customers makes a great many labels for all kinds of these commercial products, and uses an EXAIR Gen4 Ionizing Bar immediately prior to the printing operation:
The Gen4 Super Ion Air Knife is a powerful static eliminator that prevents jamming, tearing, shocks and dust build up by neutralizing static and blowing away the debris.
The Gen4 Super Ion Air Knife combines the quiet and efficient Super Air Knife with the compact design of the rugged Gen4 Ionizing Bar resulting in a total solution to remove static electricity from plastics, webs, sheet stock and other product surfaces. Removing the static helps reduce or eliminate the process issues that the static electric causes, allowing for greater production speeds, improved product quality and a cleaner product.
The Gen4 Super Ion Air Knife floods an area or surface with static eliminating ions. With a uniform airflow across its length, misalignment to critical surfaces like webs is avoided. The force can be adjusted from a light breeze, to a full out blast of air. The Gen4 Super Ion Air Knife is electrically powered, is shockless and has no moving parts.
How It Works
In the diagram above, compressed air flows through an inlet (1) into the plenum chamber of the Gen4 Super Ion Air Knife. The flow is directed to a precise, slotted orifice. As the primary airflow exits, it creates a uniform sheet of air across the entire length, pulling in in surrounding air (2). An electrically powered Gen4 Ionizing Bar (3) fills the curtain of air with positive and negative charges. The air stream delivers the static eliminating ions to the product surface (4) where it instantly neutralizes static and cleans off dust and other particulates.
The Gen4 Super Ion Air Knives are powerful tools, and very quickly dissipates 5kV of static even at low compressed air supply pressures. At 5 PSIG, only 3.7 SCFM (0.3 BAR, only 105 SLPM) of compressed air per foot of length is required!! Sound levels are also very low, resulting in quiet operation.
Added Features –
Compressed Air Inlets are provided on each end and the bottom of the Super Air Knife
Thicker shims can be installed easily if a harder air flow is needed
Emitter points are sharp, durable stainless steel
The high voltage cable is armored to resist cuts and abrasion, and has integral grounding. Threaded bayonet connector is fully assembled and ready to use
Gen4 Ionizing Bars and Power Supplies are UL Component Recognized to U.S and Canadian safety standards and are CE and RoHS compliant
Power Supplies are 115/230 VAC selectable and come with 2 or 4 outlets
Standard lengths from 3″ to 108″ (76mm to 2743mm) are offered, and custom lengths are available to meet your process needs
Successful applications include web cleaning, pre-paint dust removal, shrink wrapper machinery, printing equipment, package cleaning,and bag opening/filling operations.
If you have questions about Gen4 Super Ion Air Knives, other types of Static Elimination products, or any of the 16 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.
The video below provides details on the simple conversion to the new Gen4 style Super Ion Air Knife from the previous style or the addition of a Gen4 Ionizing Bar to an existing Super Air Knife to add static elimination to an existing blow off.
If you have questions about the Gen4 Super Ion Air Knife or any of the 16 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.
Here in the Northern Hemisphere, we are in the middle of winter and that means extremely dry air, and frequent shocks when reaching for a door knob after walking across a carpeted surface. While a shock is mildly uncomfortable and can be annoying to us, the presence of static electricity in an industrial manufacturing process can be much more problematic.
Problems that static cause range from operator discomfort to increased downtime to quality issues. Dust can cling to product, product can cling to itself, rollers, frames, or conveyors. Materials may tear, jam, curl and sheet fed items can stick and mis-feed. Hazardous sparks and shocks can occur, possibly damaging sensitive electronics.
EXAIR has put together a useful tool, the Basics of Static Electricity white paper with Interactive Regions to help a person learn more about static.
Topics covered include Electron Theory, Causes of Static Electricity, Triboelectric Series chart, and Types of Static Generation. Also, the white paper covers the areas of How to Control Static Charge Buildup, Determining the Source of the Static Buildup, Eliminating or Minimizing the Source Causing the Buildup, and Treating Static Buildup.
The Treating Static Buildup is a comprehensive review of the EXAIR Static Elimination products and how each technology is best applied to different processes and applications.
To receive your copy of the Basics of Static Electricity white paper, click the photo above or the link here.
If you would like to talk about static electricity or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
One of the best ways, in industry, to generate a static charge is to roll or unroll non-conductive materials such as polymer films, plastic sheet, etc. It’s common to see static charges well in excess of 10,000 volts in such operations, like the one I discussed with a customer recently.
One of the best ways, in industry, to dissipate a static charge is to use ionized air. There are different methods of doing this; one of the most popular is to effect a Corona discharge, via a high voltage, low amperage electric current. This is precisely what EXAIR’s Static Eliminators provide: a Corona discharge produces a bulk of both (+) and (-) ions in the enormous volume of high velocity air flow generated. When these (+) and (-) ions flow onto a surface charged with (-) and (+) ions, they cancel each other out, leaving a net neutral charge. Static, eliminated!
By combining an Ionizing Bar with a Super Air Knife, as Super Ion Air Knife provides rapid static elimination AND blow off of any dust, chips, or debris that was being statically held. The laminar curtain of ionized air not only maximizes the rate of static dissipation, but is also ideal for stripping/sweeping away any debris, leaving a clean, static-free surface. No more jamming, tearing, nuisance shocks to operators, dust attraction, or any of the other host of problems associated with static electricity.
The ionized air flow can be precisely regulated to whatever level it takes to get the job done. At 100psig, the powerful, high velocity blast will dissipate 5,000 volts of static charge in 0.18 seconds. If the material is fragile, or if that kind of air flow might disrupt the process, it’s not a big deal…even at 5psig supply pressure, that same 5,000 volts is dissipated in 0.40 seconds. That’s how it works on the plastic roll above – with just a whisper of ionized air flow from a Super Ion Air Knife, they consistently reduce the resultant static charge to less than 400 volts…far below the threshold for the nuisance shocks they wanted to avoid.
They’re on the shelf in lengths from 3 inches to 9 feet long, and we can make custom lengths in three days after receipt of an order. The 115/230VAC GEN4 Power Supplies are available with 2 or 4 outlets, to energize any 2 or 4 EXAIR GEN4 Static Eliminators.
Versatile. Efficient. Effective. Quiet. Safe. And, readily available. If you’d like to discuss a static problem, give me a call.
EXAIR offers meters to measure the level of physical parameters such as sound and static. Each meter has sensitive electrical circuitry and a periodic calibration is recommended to ensure the meter readings are tried and true.
The model 9104 Digital Sound Level Meter is an easy to use instrument that measures and monitors the sound level pressure in a wide variety of industrial environments. The source of loud noises can be quickly identified so that corrective measures can be taken to keep sound levels at or below OSHA maximum allowable exposure limits.
The sound meter comes from the factory with an NIST (National Institute of Standards and Technology) certificate of accuracy and calibration. As a good practice, EXAIR recommends a yearly calibration of the instrument, and we offer a service that calibrates the unit to the same NIST standards and provide a written report of the calibration.
The model 7905 Static Meter allows easy one-hand static measurements. It is useful in both locating sources of high static charge and checking the reduction of static after treatment with an EXAIR Static Elimination product. The unit is sensitive and responsive, and indicates the the surface polarity of objects up to +/- 20 kV when measured from 1″ away.
It is also recommended that the Static Meter be calibrated on a yearly basis. EXAIR offers (3) levels of calibration service. The first two provide calibration in accordance with MIL Standards using accepted procedures and standards traceable to NIST. The third calibration service conforms to the same Mil Standard, as well as ISO/IEC standards.
Annual calibration service of your EXAIR Digital Sound and Static Meter, along with proper care and storage, will keep your meter performing tried and true for many years, providing accurate and useful measurements.
To initiate a calibration service, give us a call and an Application Engineer will issue an Returned Good number, and provide instructions on how to ship the meter to EXAIR.
If you have questions regarding calibration services for your meters or would like to talk about any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
Recently a customer called in to EXAIR to discuss a static issue in a stretch wrap process in the plant. Stretch wrap is a highly stretchable plastic film. The elastic recovery keeps the wrapped load tightly bound. The most common stretch wrap material is a linear low-density polyethylene or LLDPE. The combination of the stretching of the plastic film and the sliding of the film on the cardboard boxes as it is being wrapped causes a build up of static. This static can cause serious havoc and issues in the process including personnel shocks, zapping counters and other sensors causing failures, and preventing marking systems from delivering good information on to the stratch wrap.
The discussion started with minimum and maximum load sizes and how to design a system that would work with all configurations and be as flexible as possible. We spoke of dimensions and where we could we could mount on 3 sides, and so forth.
Then came the question that we invariably get to and that is ‘what issue does the static cause and how does it affect the rest of the process?’ The answer here simple, ‘an operator has to write a code number on the side and affix a label, and in doing so, receives a shock.’ When it was determined that only a small section of one side of the load needed to be treated, the solution was simple. We proposed an 18″ Ionizing Bar and Power Supply. Because the machine had a fixed datum, all loads would pass within 1-2″ of a vertically installed Ionizing Bar, so no adjustment is needed for different load sizes.
The Ionizing Bar quickly dissipates a strong static charge as shown in the chart below.
EXAIR offers many systems for total static control. When static is a problem on moving webs, sheet stock, three dimensional parts, extrusions or packaging, EXAIR has a solution.
To discuss your application and how an EXAIR Static Eliminator would help out, feel free to contact EXAIR and one our Application Engineers can help you determine the best solution.