Heat shrink wrapping of bundles: techniques, solutions, comparisons and advantages of a packaging technology that has revolutionized industry and distribution alike. > Texts by Vincent Bandini, Massimo Beretta, Manuel Bolzoni, Giuseppe Buttazzi, Gabriele Folli OCME Competence Library >

Charles Darwin (synthesis of the thought expressed in The Origin of Species by Means of Natural SelectionӔ, 1859) ver recent years, the evolution of distribution platforms has triggered, on a global scale, a process of reciprocal interference between consumer habits and packaging technologies. This interaction is clearly seen in the dynamics of the composition of the retail pack. In fact many products, particularly in the drinks sector, are now available in multiple retail packs which are taken off the shelves and placed directly into the trolley. To enable the consumer to perform this simple...

Figure 3 Figure 2 Triple track fi lm outfeed wrapping area Film path diagram from the infeed reels to the heat shrink oven >

Two types of technology may be used to create a bundle using heat shrink fi lm: the sealing bar shrink wrapping machine or the continuous shrink wrapping machine. Sealing bar technology uses fi lm originating from two reels that is laminated and wrapped around a cluster of containers. Film sealing is carried out by a bar/counterbar sealing unit through which a resistor passes; when activated this resistor cuts and seals the fi lm around the pack. The pack then enters the oven where the fi lm is then heat shrunk. This type of technology has, however, limitations both as regards speed and as regards...

he cutting and continuous fi lm system is one of the two main components of the shrink wrap packer. OCME has adopted a cutting system that guarantees high reliability over time thanks to the combined blade and counter-blade action. This means less wear on the cutting blade does not require complicated adjustments, in contrast with the systems used by the majority of manufacturers, involving fi ne adjustments of the blade with respect to the counter-blade. The other component of the Vega shrink wrap packer on which Ocme has focused its R&D efforts over the years is the heat shrink oven which,...

Figure 4 The basic units of the machine are produced in series and then customized on the basis of the clients design >

OCME Secondary packaging he advent of the heat shrunk bundle revolutionized the approach of the consumer and of distributors to manyproducts. OCME has made its own contribution to this technology, launching its fi rst range of machines which offered fl exibility levels never experienced before. OCMEs spirit of innovation and its constant commitment to the development of avant-garde solutions have enabled OCME technology to become a reference point also in the fi eld of heat shrink wrapping systems. LetҒs look at the Vega in detail Today, the Vega line comprises numerous models destined for the...

Figure 6 Detail of film centring device Detail of antistatic bars for the removal of electrostatic charges from the film Figure 5 Figure 7 Detail of channelling with dual track and shaped guides specific for each product >

Figure 10 Detail of dancer with dual track configuration Figure 9 Dancer with film tensioner with easy and practical insertion Detail of reel holder expanding shaft Figure 8 Figura 11 Detail of splicing device of automatic reel changing system >

OCME Secondary packaging This system serves to cut the fi lm cleanly and precisely at the speed required, always repeating the operation at the desired point, especially when pre-printed fi lms are used. Depending on the speed, the Vega adopts different cut command systems. For up to 60 cycles/minute an electromagnetic clutch is used to activate cutting. The device controls the movement of the blade and counter- blade which, in order to reduce stress and wear on the mechanism, are fi tted on the elliptical pinions in order to ensure the smooth movement of the cutting cycle (initial speed low,...

Figure 14 Upper stabilizer belt at the oven infeed area, helps guarantee the stability of the products Figure 16 Resistor unit of heat shrink oven Figure 15 Film winding fl ight bar at adjustable height to suit all container heights >

1 2 3 4 > Cross-section of the heat shrink oven, schematically indicating the internal air flow. The different colour of the arrows empirically indicates the air temperature at that position Full page figure size="-1">

Phase 1 The product enters the heat shrink oven Phase 2 Due to the effect of the air coming from the side blowers the film swells Phase 3 Phase 4 Continuing along its path, increasingly more heat is applied to the film which starts to shrink The bundle takes on its final shape in the final stage of its path >

Tray feeding from pallets The capacity of the blank magazine can be extended by a robotic system that picks up the blank directly from the pallet. The pallet arriving from the paper mill simply needs to be positioned on the conveyor belt by the forklift truck driver who duly removes the strapping, after which the machine operates entirely automatically for prolonged periods (autonomy varies on the basis of the speed of the machine, the capacity of the pallet conveyor and the thickness of the blank). The operator does not, therefore, have to manually lift piles of blanks which by the end of a...

Size changeover Size changeover operations have been subjected to careful rationalization in an endeavour to adopt solutions that offer the best overall results. An electronic solution has therefore been develo- ped, with a view to simplifying machine opera- tion, reducing the number of components and eliminating potential problems. We decided to opt for a step-by-step guided procedure that can be carried out by a single person, even without special training (including temporary or seaso- nal workers) with easily identifiable parts and a colour coding system. Once automatic changeover has been...