A method for wrapping a load with a film uses a wrapping machine. The wrapping machine is provided with an unwinding apparatus including pre-stretching rollers, a return roller and a force sensor to measure a wrapping force of the film. The method includes rotating the unwinding apparatus and the load relative to one another with a rotation speed and unwinding the film, measuring an effective wrapping force of the film, filtering the effective wrapping force by a first filter, to obtain a filtered wrapping force, and calculating by a PID control algorithm an instant film length to be supplied per rotation based on the filtered wrapping force. The method also includes filtering the instant film length by a second filter, calculating an instant rotation speed of one pre-stretching roller based on the instant filtered film length and the rotation speed, and rotating the pre-stretching roller with the instant rotation speed.

A wrapping machine for wrapping material around a load includes a wrapping unit to wrap a portion of the material around the load and a supplying unit to supply the material portion to the wrapping unit. The wrapping unit includes wrapping device to unwind the material portion from the supplying unit and wrap it around the load. The wrapping unit includes a supporting ring, rotating around a wrapping axis and provided with a plurality of wrapping rollers, and an unwinding arm having a first end rotatably fixed to the support ring and a second end supporting at least one unwinding roller to abut and guide the portion of material towards the load during wrapping. The unwinding arm is movable to move the unwinding roller to/from the load during wrapping.

A wrapping machine for wrapping groups of products with an extensible plastic film to form bundles includes a conveyor for supporting and moving a group of products along an advancing direction inside the wrapping machine, a supporting device for supporting the group of products received from the conveyor, a wrapping unit for wrapping a portion of film around the group of products, supported by the supporting device, in order to form a bundle, and a supplying unit to supply the wrapping unit with the film portion separated from the film. The supporting device includes a gripping device that holds an initial flap of the film portion during the wrapping of the group of products, a containment device to abut against the group of products to guide the products when moved along the advancing direction through the wrapping unit and/or to support and restrain the group of products during wrapping.

Devices and method for accurately measuring the length of film feeding into a pre-stretch carriage from a supply roll and the length of film exiting after the pre-stretch carriage in order to accurately determine the actual percentage of film stretch occurring during the wrap cycle are provided. A first idler roller mounted on the frame of a pre-stretch carriage before the pre-stretching rollers and second idler roller mounted to the frame after the pre-stretching rollers are included. Optical rotary encoders are driven directly by idler roller shafts as stretch film passes around the shafts during film application. Systems including internet of things (HOT) devices can be fitted or retro fitted to a wide variety of stretch wrapping machines.

A method determines a wrapping configuration of a film wrapped around products to form a palletized load to be moved along a path. The method includes using a defined wrapping configuration, measuring physical quantities acting on the load as a result of movements and/or stresses when the load is moved along different test paths, obtaining a path as a suitable composition of base elementary path stretches, obtaining physical quantities acting on the load along the path as physical quantities associated to the base elementary path stretches, positioning the load on a motion platform, operating the motion platform based on the physical quantities to simulate movements and/or stresses acting on the load moved along the path, checking if the load has remained stable and/or compact, modifying the wrapping configuration if the load did not remain stable and/or compact, and repeating the steps.

A method, apparatus and program product implement top layer containment operations to optimize containment of various types of loads such as loads with top/slip sheets, ragged topographies, and/or inboard portions. Bidirectional control of the elevation of a web of packaging material may be performed within one or more revolutions between a load and a packaging material dispenser to selectively engage one or more corners of the load with a web of packaging material while passing the web of packaging material inwardly of one or more other corners of the load.

A method, apparatus and program product utilize a torque control algorithm constrained by a speed window to control the dispense rate of a packaging material dispenser when wrapping a non-cylindrical load with packaging material. In particular, a dispenser motor of the packaging material dispenser that is controlled by a VFD may be driven to maintain a substantially constant torque, while also constrained to operate within a speed window that is based at least in part on a rate of relative rotation between the packaging material dispenser and the load.

A method, apparatus and program product utilize curve fitting to control a dispense rate for a packaging material dispenser. Predicted demands at a plurality of rotational positions of a load relative to a packaging material dispenser may be used to generate one or more points to which a curve may be fit, such that dispense rates may be determined for rotational positions between those for which predicted demands have been determined using the curve.

A method, apparatus and program product implement top layer containment operations to optimize containment of various types of loads such as loads with top/slip sheets, ragged topographies, and/or inboard portions. Bidirectional control of the elevation of a web of packaging material may be performed within one or more revolutions between a load and a packaging material dispenser to selectively engage one or more corners of the load with a web of packaging material while passing the web of packaging material inwardly of one or more other corners of the load.

A method, apparatus and program product may evaluate a packaging material to determine various metrics associated with the packaging material. An apparatus may be used to sense flaws in packaging material, and in some instances, to accommodate such flaws by temporarily increasing a dispense rate of a packaging material dispenser.