Tag: static electricity

Static Electricity – What is it?

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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

Super Ion Air Knife Improve Cycle Rates in an Injection Molding Process

Published on by John BallLeave a comment

A die manufacturer created a 12” wide by 24” long (30.5cm X 61 cm) tool for an injection molding machine that contained 80 cavities for an automotive supplier. As contracted with their customer, the goal was to have 30 injection per minute to create 2400 parts every minute.  The tool was designed with 2 chambers, each containing 40 cavities to control production rates.  Also as part of the contract, the automotive supplier required a pre-production approval before signing off on the purchase order.  As they attached the tool to the injection molding machine for a trial run, they began to notice that some of the parts were sticking to the cavities.  In the first 30 minutes, they stopped the machine as they only averaged 16 injections per minute with only 50% of the parts falling out of the tool.  They did notice that they could feel the static electricity on their arms when they reached into the tool to remove the parts.  To try and improve the cycle rate, they attempted to mount a 12” (30.5 cm) pipe with drill holes above the tool. Many manufacturers attempt this because it is simple and easy to do; but, this style of blow-off is very inefficient and not very effective.  As they began the next trial, they did see a slight improvement.  It increased the cycle rate to 19 injection per minute and it was removing 75% of the parts.  It still was not good enough for the automotive supplier.

Super Ion Air Knife Kit includes Super Ion Air Knife, Power Supply, filter, regulator and shim set.
Super Ion Air Knife Kit includes Super Ion Air Knife, Power Supply, filter, regulator and shim set.

The die manufacturer was under pressure to find a solution as he did not want to redesign or rebuild the tool. He noticed that EXAIR was a leader in Static Eliminators and Blow-off equipment, so he contacted us.  In our discussion, he explained how he needed to remove the static and remove the parts quickly out of the tool.  I suggested our model 111212 Super Ion Air Knife Kit.  It is 12” (30.5 cm) long, and it can be mounted easily across the width of the tool.  With a 40:1 amplification ratio and both positive and negative ion streams, it can remove the static and push the parts very effectively.  Once they installed the Super Ion Air Knife, they began the operation once again.  They initially noticed that all the parts were being ejected from the tool.  When they measured the cycle rate, it was running at 33 injection per minute (exceeding the requirement).  The tool was approved and the die manufacture was very pleased.

When it comes to removing static and blowing parts, EXAIR has a great range of products. We can do it very efficiently, quietly, and effectively.  If you have any issues with injection molding, EXAIR may have the product to help you.  You can discuss your applications further by contacting one of our Application Engineers.

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

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

Super Ion Air Knife Assists Brewery with Can Filling Operation

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A small brewery called looking for a static removal solution for their can filling, conveyor line. The empty cans are fed from a stacked palletizer that raises up and then an arm pushes the cans over to a large feeder tray where they are then funneled down a chute that narrows until the cans are in a single row. They run 2 separate cans on the same line at different times. The first can is painted and seems to feed fine to the conveyor. The second can is shrink wrapped with a film label. As the wrapped cans are fed down the chute, they rub against the guide rails of the conveyor and each other generating a static charge, causing them to corral at the opening to the conveyor, 2 – 3 cans wide, which restricts the flow of the cans. The customer then has to halt production and manually clear the line and feed the conveyor.

The area where they are seeing the most problem is right at the narrow opening that takes the cans down to a single row. The width of this opening is roughly 8.5″ wide, so I recommended they mount a 9″ Super Ion Air Knife about 12″ above the opening, flooding the area with ionized air. The Super Ion Air Knife is our Super Air Knife with an Ionizing Bar attached to provide a laminar sheet of ionized airflow across the entire length of the knife. The customer was concerned that their compressed air supply was close to being at max capacity so I suggested they operate the unit at a lower supply pressure. This would not only reduce the air consumption but also control the output flow and velocity so the cans are not disrupted, while still allowing for effective static dissipation.

Super Ion Air Knife
Super Ion Air Knife – delivers a sheet of ionized air to eliminate surface static up to 20′ away.

Static electricity is a common nuisance in canning and bottling applications. If you are experiencing similar problems with your process, please contact one of our application engineers for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN