Static Electricity – What is it?

Now that the air is cooling and the humidity is dropping, you may often experience the phenomena of static electricity, and the resultant shock when touching something metal. As a child, you may have learned about static electricity by rubbing a balloon on your head and then seeing it stick to the wall. What is the science behind static electricity?

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All materials are made up of atoms, which have a positively charged core called the nucleus surrounded by a cloud of negatively charged electrons.  Each material is different, and in some types of materials the positive nucleus has a very strong pull on the electrons while in other materials the pull is very weak.  If we were to put a strong  pull material in contact with a weaker pull material, atoms from the weak pull material will migrate, and when the materials are separated, additional electrons will remain with the strong pull material.  Due to the overall increase in electron quantity, the material becomes negatively charged and the other material becomes positively charged. If the materials are rubbed together, the opportunities for the electron migration increases, and thus more electrons are exchanged.

Electrons build up more easily in dry conditions. When the air has humidity, static build up is less common because a very thin layer of water molecules coat most surfaces, which allows the electrons to move more freely and make most materials conductive and static free.

In some cases, static electricity can be a good thing – laser printers and photocopiers use static electricity to transfer ink from the drum to the paper.  Also, some power plants and chemical factories use static electricity  to remove pollutants in a process that takes place within the smokestack.

But generally when EXAIR gets involved, it is because the static electricity is causing an unwanted build up of static charge that affects a manufacturing process. The results of a static charge imbalance can result in a shock to an operator, materials sticking together, poor print quality, sensor or counter malfunctions, bad surface finish, or any number of other problems.

EXAIR offers systems for total static control, such as the Super Ion Air Knife and Ionizing Bars for wide applications such as paper, film and plastic webs, the Super Ion Air Wipe for narrow, continuously moving materials such as wire, tube, or extrusions.  Also offered are the handheld Ion Air Gun for use on three dimensional parts prior to assembly, packaging painting or finishing. Other options include the Ion Air Cannon for limited space or remote mounting applications, Ion Air Jet for tight spaces and concentrated airflow, and the Ionizing Point to provide close distance and accurate static removal.

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Super Ion Air Wipe

To discuss your static elimination concerns , feel free to contact EXAIR and one our  Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Spark Photo Credit – Eric Skiff – via Creative Commons License

Why EXAIR Static Eliminators Are Better Than Passive Eliminators

The question comes up quite a bit around this time of year as to why an EXAIR Static Eliminator is better than using a passive static eliminator to eliminate the static.   To further the explanation of a passive static eliminator, it is typically called static tinsel and is found in a variety of forms. Passive eliminators are grounded wire or strap and must come in contact with the surface of a part in order to dissipate the static charge on only that surface.  This is generally found in the form of a bare wire or some type of conductive material (copper) that is strung across the path of your parts and must come into contact with the surface of your part.   A conductive material bar is shown below.

Passive Static Eliminating Bar
Passive Static Eliminating Bar

In order for this to eliminate the static on the part you must have the fabric actually contact the surface of your part.   There are several points that this can cause an issue, the first being this item drags across the surface of your product which can wear the conductive fibers down leading to the eliminators needing to be replaced.   Second, if you have a delicate, printed, or high gloss surface, you may not want anything to touch the surface and risk a blemish.   Third, these can collect dirt and debris which may become transferred to the product.   Last, complicated shapes cannot easily be met with the passive static eliminators, these are only going to work well with flat surfaces.

Active static eliminators, such as the Static Eliminators Product Line from EXAIR offers a variety of ways to actively eliminate the static on a surface without ever touching the product.   These are ideal for delicate surfaces, painted surfaces, complicated shapes, or even flat sheets.  The EXAIR line is available with or without compressed air assist which will not only utilize your compressed air efficiently while eliminating a static charge but also blow the debris or particulate off the part.   Units without compressed air operation can eliminate static charges up to 2″ away from a surface while a unit with compressed air will eliminate static up to 20′ away.

A Sample of EXAIR Static Eliminators
A Sample of EXAIR Static Eliminators

 

Because the units do not contact the parts there is no need for being concerned about contamination being transferred to the part, the eliminators will not wear down from dragging across a part or surface. EXAIR static eliminators are also low maintenance products.

To top it all off EXAIR will honor a 30 day guarantee to test the products in your facility.  As well as honor a 5 year built to last warranty on compressed air products and a 1 year warranty on any electrical component.

If you would like to eliminate your static problems, contact us. 

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Ion Bars Remove Static, Help Improve Labeling Quality

I worked with a customer recently who was experiencing a static issue when trying to apply a bar coded label to their cardboard box. The boxes travel down a conveyor then passes by a labeler that uses a mechanical arm with air vacuum to hold the label in place. As the box passes by a sensor, the arm applies the label to the corner (front and side) and then the box passes by an applicator brush that ensures the label is firmly applied.

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They were starting to see wrinkles in the label as it passed by the brush and were thinking the label was holding a static charge which was making it be rejected by the box during the process. They were experiencing this about every other box. When it would occur, they would need to stop the line and manually check to make sure the label was seated properly. As a result, this was negatively affecting their production time and increasing wasted labels.

Since they thought it was the label holding the static charge, they wanted to use one of our Ionizing Bars to remove the static from the label as it was attached to the arm. The Ionizing Bar produces a high concentration of positive and negative ions able to dissipate 5 kV in 0.30 seconds, 2” from the object’s surface. It is also UL listed for safety and RoHS compliant.

Ionizing Bars Work

The customer is local, so they asked if someone from EXAIR could visit their location and take a look at their process. I was able to make the appointment for the next morning and brought a few of our Static Eliminating products and a Static Meter to take some measurements. By measuring within 1” of the surface of the product, the Static Meter measures the voltage and polarity up to +/- 20 kV.

Upon arrival, I was directed to the labeler and took a measurement – I was only getting a reading of about 0.2 kV. I then decided to take a reading on the box itself as it traveled down the conveyor. Now I was getting a reading of 3 – 5 kV, which meant that it was the box and not the label that was holding the static charge.

Since the customer could get within 2” of the surface of the box, they were able to mount a 6” Ionizing Bar vertically to remove the static prior to the labeling process.  This helped to greatly reduce the downtime of the line.

If you have a similar issue or would like to discuss your particular application, please contact one of our Application Engineers at 1-800-903-9247.

Justin Nicholl
Application Engineer
JustinNicholl@EXAIR.com
@EXAIR_JN