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.