Eliminating Static On An Automatic Stretch Film Machine

Another recent application I’ve worked with from our Peruvian Distributor involved mitigating static on the outside of plastic shrink wrap. The customer manufactures a variety of different containers which after produced are then palletized for shipment to the end-users. They must ensure that the containers are adequately wrapped so that any dust/debris from the environment doesn’t come into contact with them and pose a contamination issue. This static charge would also at times cause the roll to jam up in the machine, and if left unnoticed for any length of time created quite a mess to untangle and fix. In addition, that static build-up that was occurring also manifested into painful shocks to the operators.

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Automatic Packaging Machine

To wrap them, they’re using an automatic plastic wrapping machine. They wanted some type of a solution that could be permanently affixed to the machine and eliminate the static on the film as it was unrolled. As two non-conductive layers of material are separated (in this case two layers of plastic wrap), a strong static charge is produced. Mounting an Ion Bar on the outside of the stretch film provided an excellent solution for them as they didn’t have to have an operator standing by keeping an eye on it. They weren’t concerned about static on the underside of the material as much as this also allowed for the plastic to adhere better to itself as its wrapped around the pallet. Typically, we’d recommend an Ion Bar or other Static Eliminator on either side of the material, but in this case the static charge there was wanted.

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Gen4 Ion Bars without compressed air requirement

Since we were able to mount the bar within 2” (50mm), it didn’t require a supply of compressed air to carry the ions to the surface of the plastic. As an extra layer of precaution, they also purchased an Ion Air Gun that was used to treat the outsides of the pallets again as they’re removed from the machine. Doing so has now prevented them from having to inspect and re-wrap pallets as needed. Since some runs may span over several days, there were times that they had to re-wrap products more than once as the dust build up was not acceptable to their customer. They estimated that 40-50% of the pallets had to be re-wrapped at least once, taking anywhere from 5-10 mins each after accounting for removing the old wrap, placing it back into the machine and re-wrapping.

With a wide variety of Static Eliminators available from stock, both with and without a compressed air requirement, EXAIR has a solution for your static problems. As we move into the cooler and dryer months of the year (If this hot summer ever ends), static becomes much more of an issue. Don’t wait until it becomes a serious problem and get in touch with an Application Engineer today!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exir.com
Twitter: @EXAIR_TD

Solving Static Problems with EXAIR Ion Bars

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This plastic film stretching machine needed a viable static elimination solution.

The relationship between humidity and static is something we’re very familiar with at EXAIR.  As temperatures drop and humidity decreases, the reduction in moisture content within the air translates to an increase in static .  This is because higher moisture content in the air creates a surface layer of moisture that dissipates accumulated static charges.  When this surface layer disappears, static forms quickly and easily.

Fortunately, we have a full line of static eliminating equipment suitable for use in removing static related process disturbances.  For example, the photo above shows a plastic stretch wrapping machine at its dispensing point.  As the plastic is pulled from the roll static builds up quickly and this customer needed an easy, reliable solution to remove the static.  Ideally, they wanted something that would not require compressed air, but could still mount closely to the machine and remove the static charge.

The solution for this application was a series of two 24” Ion Bars mounted on each side of the film.  As the plastic is unrolled it passes through the opening created by the Ion Bars, eliminating the static charge.  The machine required no significant downtime to install this solution, and nothing within the machine setup had to be modified.

This type of setup was ideal because it treated the static at the proper point within the process, used no compressed air (as requested by the customer), and it provided a simple installation to solve the problem.

Plastic sheets and films that are being separated after full contact can generate significant static charge.  If you have a film/sheet application, or another static related need, contact an EXAIR Application Engineer.  We’d love to help you find a solution.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

Stretch Wrap Static 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.

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Stretch Wrap Operation

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.

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Ionizing Bars Treating Top and Bottom Surfaces

The Ionizing Bar quickly dissipates a strong static charge as shown in the chart below.

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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.

Brian Bergmann
Application Engineer

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