motorised pre-stretch

The power pre-stretch is a special device which allows the best utilization of the stretch film quantity; moreover, it permits to wrap light and un steady pallets that couldn't be wrapped with different frictioning systems. To be called "power pre-strectch" - this film supply system must include at least a pair of covered rollers linked to each other by a transmission system in such a way that the first and the second roller turn at different speeds, and it must also include an electronically assisted motor that operates the rollers according to the stretch film delivery speed. Coming into contact with the surface of the two rollers, the film will then be stretched in a quantity equal to the speed difference of the two rollers, thus determining a relevant increase of the film length. To give an example, let us suppose that roller A is rotating at a speed which is double than that of roller B. As the film is obliged to adhere to the surface of the two rollers, at the exit of the supplying unit the film length will be double compared to the length initially wrapped in the spool. Think of the economic advantage of this device!: the quantity of film used to wrap a pallet through the power pre-stretch is exactly equal to the half of the quantity of film which is normally necessary when using traditional systems. That means a 50% saving on the stretch film cost! Moreover, the power pre-stretch device is indispensable when you need to wrap light or un steady pallets. Actually, a traditional film supplying system always causes the light loads to overturn, due to the strain of the film applied on the product to be wrapped. The power pre.stretch solves this problem thanks to the helped supply of the film. In fact, the stretch film is supplied in the right quantity by the rollers that are operated by a motor, which is in its turn controlled by an electronic system that measures the speed and keeps the film tension constant during its deposit on the whole pallet's surface. In this way the film is deposited on the load gently, thus preventing overturning. The stabilization of the pallet is possible due to the memory effect that "remembers" the flexibility of the previously stretched film inside the supplying device. This memory effect doesn't end with the wrapping; on the contrary, it persists for many hours, thus increasing the stabilization phenomenon progressively.