Packaging panels of expanded polystyrene used to be a problem: after wrapping the film around the product the heat in the shrink tunnel would cause the surface of the panels to wrinkle. Mac Due realized that packaging with two-reel machines required more heat for shrink wrapping as compared to packaging with machines featuring a tie-shaped wrapping system. Mac Due took on the challenge and was the first company to design a machine with tie-shaped wrapping system large enough to package panels.
Another interesting solution is the use of “Leister” units instead of shrink tunnel. In situations where “extreme” shrinking was not required, shrinking the film on the sides of the package with the use of these powerful industrial blow dryers was considered sufficient. During the shrinking process the heated air contained in the package would create air pockets, preventing the hot film from coming into contact with the polystyrene until the film was cooled.
Competing manufacturers built tie-shaped wrapping systems for panels, however the “ties” were so large that they encountered problems with the sliding of the film. These companies applied rollers to aid the insertion of the panels into the “tie” but this resulted in the disbanding of the stacks of products with some lightweight panels. MacDue met the problem by substituting the rollers with a mechanical pusher installed below. The solution guaranteed insertion into the tie-shaped wrapping system without disbanding the bundle, and allowed the machine to handle shorter products.
In 2005, Mac Due patented a new Centre-folding unit, to install in machines with tie-shaped wrapping systems. This was in response to difficulties in managing a very heavy centre-folded film reel in such large machines. Mac Due came up with an innovative solution that enabled the use of two reels of simple film, resulting in facilitated reel handling, doubling of the machine’s autonomy, and easier printing on film.