Packaging

Equipment that carries the roll safely from unwind to rewind on flexible packaging lines, unwinds it at the right tension and rewinds it cleanly.

In flexible packaging production, material travels in roll form from one end of the line to the other. Plastic film, paper, aluminium foil and laminated structures are unwound, pass through printing, laminating or slitting, and are rewound into a finished roll. At both ends of that cycle, the components that carry, drive and hold the roll directly affect final product quality.

Roll handling on a packaging line

A typical packaging line has three basic zones: the unwind, the process section and the rewind. At the unwind, the parent roll is held by its core and paid out against a controlled resistance. Through the process section the web has to hold its tension and its position on the line; if it does not, the result is print misregister, creasing or lamination defects. At the rewind, roll hardness and edge quality are what count. With frequent job changes, fast roll changes also matter for efficiency.

Which equipment goes where?

Air shaft: Grips the core from the inside, transmits torque without slipping and speeds up roll changes. Where operators handle shafts often, the low weight of an aluminium air shaft is a clear advantage.
Friction shaft: On the rewind side of a slitter, it lets each core sitting side by side on the shaft turn according to its own diameter. See the friction shaft and friction rings pages.
Safety chuck: Connects the shaft to the machine frame, transmits torque and lets the shaft be lifted in and out quickly. Depending on the frame design, an inside-frame or frame-mounted type is used.
Brake and tension control: At the unwind, a pneumatic brake provides the unwinding resistance, while a tension controller drives the brake or motor from load cell or dancer feedback to keep tension constant as the roll diameter changes.
Web guiding: A web guide controller follows the web edge or a printed line with a sensor and corrects lateral drift of the roll.

What to consider when selecting

The inside diameter and material of the core (board, plastic or steel) determine the type of grip the shaft needs.
Roll weight and width influence the shaft body material and the type of safety chuck.
As line speed rises, balance and runout become more critical.
If cores on a slitter rewind build up to different diameters, a friction shaft is worth considering.
Shaft journal dimensions should be checked against a drawing of the existing machine.

For size options see the technical dimensions page, or request a quote for your application through our contact page.