Overwrappers, are typically found on end-of-line packaging processes where finished product is collected and arranged in batches for shipping. Products such as bottles or cartons are sometimes first batched in a tray and finally, strong plastic film is shrink-wrapped over the entire package to secure the products for transportation and subsequent display at the point of sale.
With the many different product types that may require over-wrapping as an automated process, this is an ideal application area for motion control where the motion program can easily accommodate variables such as package size and height, and film length or speed, to easily allow and adjust for different products and package configurations to be batched – on the same line as a continuous process.
System overview
In this system configuration, a NextMove e100 multi-axis motion controller has three MotiFlex e100 servo drives connected over Ethernet POWERLINK controlling the horizontal and vertical wrap axes that combine to move an arm to spread the film, and the film feed roller mechanism. Some systems use a mechanical film wrap arm with linkages to generate both horizontal and vertical motion from one driven axis.
Film feed must initially advance before the product reaches the conveyor then synchronize in speed until the product passes beyond the film feed position. Film is then advanced rapidly to match the film arm as it passes over the product. Registration of any printed material and correct feed length is all managed by the motion controller.
In this system, a fourth ‘virtual axis’ is used within MINT to control the timing of film cutting which is triggered after the requisite amount of film material is fed. The machine also includes three product conveyors that are each controlled and powered by ABB ACS355 inverters that feed the products through the machine.
The central conveyor has an auxiliary encoder connected to the NextMove e100 to track position and speed. A registration sensor placed at the end of the first conveyor is triggered when the tray and bottles reach it. From these measured positions, the MINT program can initiate motion similar to a ‘flying shear’ that is used to feed the film over the moving bottles, cut the film to length and then retract the arm ready to start the process again when the next batch of bottles are presented. Once the bottles are wrapped they will move and trigger another sensor and NextMove e100 will turn the heater on and control its timing to shrink the wrap around the bottles.
Gated buffer systems - some machine types use gated conveyors to stack up a buffer of product waiting to be wrapped.
Stationary wrap - in this approach the wrap around the product takes place on a short conveyor of approximately the same length as the package, that remains stationary as material is passed over and around by a rotating arm.
Robot 'End of Line' Palletising
The next phase after over-wrapping and labelling is generally handled by a robot due to size, mass and demanding repetitive operation required to palletise the wrapped product.
ABB is a leading supplier of robotic solutions for end of line systems which can be easily integrated with our control systems including our new IRB 460 palletising robot.
In addition to our MINT solutions we can also offer IEC61131 PLCopen motion solutions with our AC500 PLC range using ProfiNet or EtherCAT to control ABB machinery and micro drives. Safety can be added directly to the PLC using the AC500-S safety processor.
Related motion features :
Homing to a datum (which can be avoided using motors with absolute feedback reducing start-up time)
Fast latch inputs feature on our drives and motion controllers and ensure precise registration of product and printed material
Smooth change of target position on the fly to correct final position of the film feed if print registration is required
CAM motion can be used for continuous smooth motion electronically geared to material feed. CAMs can be downloaded, stored, and modified on demand.
Electronic geared motion including CAM, virtual clutch, advance / retard corrections to synchronize axes as required
FLY segments provide constant acceleration geared motion segments and can be used for film feed motion geared to the main product conveyor with less data required than a CAM approach. 'S-ramp' acceleration can also be implemented to reduce film slip / stretch.
Possible system solutions for this machine type include:
NextMove e100, combined with MicroFlex e100 and/or MotiFlex e100 drives provides a real-time Ethernet based control solution for up to 16 axes of coordinated motion. Alternatively it can be used as a stepper / analog controller with Ethernet connection for factory networking.
1 to 16 axes of interpolated / coordinated motion
Mix stepper, analog and real-time Ethernet drives
Onboard digital and analog I/O which can be expanded by CANopen
High performance motion functionality with high-level Mint programming
Single point of programming and configuration / remote access via Ethernet
MINT application code can be ported between NextMove controllers and MINT module for MotiFlex e100 to provide scalable solutions.
For more information on our e100 real-time Ethernet products click here
Application notes:
The following application notes are relevant to this application:
