Tag: static electricity solution

The Generation of Static Electricity

Published on by John BallLeave a comment

EXAIR published a white paper, Basics of Static Electricity, explaining what causes static electricity; how it is generated; and steps to eliminate it. You can get this paper HERE and start removing static issues from within your plant or process.

In this blog, I would like to expand on the subject of how static can be generated.  On a molecular scale, the outer electrons that are orbiting the nucleus of an atom or molecule can be “stripped” and redistributed from one atom to another.  This will cause an electrical charge imbalance called static.  An additional electron will create negatively charged static, while atoms losing an electron will create positively charged static.  With non-conductive materials like plastic, paper, rubber, glass, etc., the electrons cannot move back to the original atom. There are three common methods of static generation that will cause this phenomenon to occur.  I will explain each one in brief detail below:

Contact

Contact: Whenever objects hit each other, electrons can be passed to or received from the surface of another object. The number of electrons being transferred is based on the type of triboelectric material.  But, with plastic bottles or trays bumping into each other on conveyor belts, static can be generated relatively easily.

Detachment

Detachment: When one material is separated from another by peeling, electrons may not be able to return to the original molecule.  Because of their larger surface areas, adhesive tape and protective films are common for generating static charges by detaching.  As an example; when the backing material is being removed from labels, the static will cause the labels to be misaligned or cause jams.

Friction

Frictional: This is one of the most common reasons for generating large static forces. It is caused by two non-conductive surfaces being rubbed together.  The amount of force being applied to the material as it slides back and forth will create higher static charges.   As an example, it is noticed when you rub a balloon on your hair.  The more times that you rub the balloon against your hair, the stronger the static forces, allowing the balloon to “stick” to the wall.  It is also noticed as sheets of material are stacked or run over rollers.

Static tends to propagate.  The more contact, detachment, and friction that occurs, the higher the static charge.  Even after the static charge is removed from the surface, it can regenerate using the same mechanisms described above.  So, controlling the static can be determined by the type of treatment as well as the location for removal.

Another variable that affects static generation is humidity.  Most process problems are noticed during the winter months as the ambient air is drier.  With a lower relative humidity, static electricity can develop easier and with greater strength.  We always refer to winter as “static season.”  You may even notice this when you walk across the carpet and get zapped by touching a door handle. 

EXAIR manufactures a large line of Gen4 Static Eliminators to remove this static nuisance.  From now until March 31st, 2024, EXAIR will be giving away a free AC Sensor, a $76.00 value, as a promotional item with a qualified purchase of the Gen4 Static Eliminators.  If you would like to discuss your application and potential static issues, you can contact an Application Engineer at EXAIR.  We will be happy to help.

John Ball
International Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

A Tale of Two Super Ion Air Knives

Published on by Russ BowmanLeave a comment

A manufacturer of plastic bottles had a problem with static charge. Right after the bottles are extruded and cooled, they have an apparatus that “unscrambles” them and places them, single file, onto a conveyor. It does so with some fabric belts and plastic rollers. If you know anything of static electricity, dear reader, you probably recognize that there aren’t too many better ways to generate a static charge than to rub plastic against plastic, or (even worse) plastic & fabric together.  Here’s a prime example of the kind of static charge you can get, just from unrolling plastic film.

The separation of the non-conductive surfaces (like when this plastic film is unrolled) is capable of generating an incredible amount of static charge.

Now, the bottle makers didn’t have a static meter, but they didn’t need one to know they had issues:  the bottles that the “unscrambler” was putting on the belt were still very much “scrambled.”  They installed a Model 112209 9″ GEN4 Super Ion Air Knife Kit, to blow ionized air up from under the bottles as they entered the belt conveyor, and they did see what they’d call an improvement, but not quite what they’d call a solution.

Unfortunately, dissipating the static from just about half of the surface area of the bottle was still leaving them with half a problem.  However, by adding a Model 112009 9″ GEN4 Super Ion Air Knife (the 112209 Kit’s Power Supply has two outlets, and its Filter Separator & Pressure Regulator are capable of handling the flow to two 9″ Air Knives,) they were able to blow ionized air down from the other side, and up from where the first one was installed.  A soft “breeze” was all it took…a stronger air flow would have worked against the “unscrambler” anyway…because even at very low supply pressures, the Super Ion Air Knives produce an extremely fast static dissipation rate.

Even with a 5psig supply…which makes for just a “whisper” of air flow, the EXAIR GEN4 Super Ion Air Knife eliminates a 5kV charge in under half a second.

If you’ve got problems with static charge, we’ve not only got improvements; we’ve got solutions. Give me a call to find out how we can help.

EXAIR Ionization Bar Eliminates Static in Printer

Published on by John BallLeave a comment

One of the big issues in winter many manufacturing and process industries experience is static.  An outside sales rep who was responsible for selling and servicing industrial laser printers contacted us after he started to receive more complaints about the quality of the print, especially with customers that used polyester sheets.  One of their customers was printing both sides of a 13” X 19” (33 X 48 cm) sheet, and they noticed that the print on the back side was blurry.  We discussed how static can cause issues like this in printing applications. A static charge can keep ink from landing in the proper location, it can cause ink to spiderweb, spread over defined boundaries or fail to penetrate its target.

Ionizing Bar
Low cost Ionizing Bars eliminate static cling.

Being that EXAIR Corporation is a leader in production and application of active Static Eliminators, we were able to discuss the issues and suggest some possible solutions. Laser printers are designed to use static to pick up toner onto a drum and to apply it to sheets of paper.  If the sheet of paper has a charge on it, that can affect the print quality because like charges repel each other.  In this application, we have two conditions that contributed to the increase in static charge on the polyester sheet, the dry air and the type of material.  Dry air in winter is pretty much a given as cold air cannot hold as much moisture as hot air can.  With a decrease in moisture levels, static fields can build to much higher levels causing discharges, the small “shocks” you experience when you touch a non-conductive material, another person or even a grounded machine.  The other static issue is material.  The type of materials involved in an application determine how they will share electrons when they rub together.  Some materials give up electrons readily and some materials tend to gain electrons.

Getting back to the application; inside the mentioned printer, a rubber roll was used to invert the paper to print on the back side.  If the paper was cellulose, it is harder to generate static as the rubber roll and cellulose are similar in sharing electrons. However, this sheet was made of polyester, it has a higher affinity to take electrons from the rubber roll. A static field would build which was enough to affect the transfer of toner from the drum causing a blurred image.

Our strategy for applying static elimination solutions is to determine the point of static generation and locate the static elimination equipment just downstream of the problem area.  In this instance, it was after the roller just before printing. The space was limited, so the customer went with model 7012 Ionizing bar with the 7901 power supply.  The positive and negative ions that are emitted from the Ionizing Bar will neutralize static fields of positive or negative polarity bringing the surface of the polyester material back to neutral.  The length of the bar was slightly shorter than the width of the sheet, however it still has plenty of capacity to neutralize the outside edges.  The end user mounted the Ionizing Bar in the center of the sheet about 0.5” (13mm) away from the surface.  After he plugged in the Ionization Bar, the static field was removed and the printing on the back side was now clear.  The end user was so impressed that he contacted the manufacturer of the laser printer to suggest they add effective static elimination as  an option for troublesome applications like his.

If you have static issues and you want to remove the pain they cause in the form of injury, lost production time and material waste, contact EXAIR and speak to one of our experienced Application Engineers.

John Ball, Application Engineer
E-mail: johnball@exair.com
Twitter: @EXAIR_jb