High Speed, High Accuracy Labelling and Packaging Solution
The main challenge of this application was to eliminate the inaccuracy associated with the standard industry approach and to design a system which would allow labels to be repeatedly applied and wrapped around 370° on a cylindrical device. The typical accuracy achieved by standard solutions is within 0.5 mm and 5 degrees from reference features on the label, however in this application the accuracies required were within 0.1mm and with no visible overlap at 100ppm.
The devices were presented to the machine in trays, and loaded onto a Tooled Beckhoff XTS system, which was used to transfer the devices between labelling modules. Three labelling modules were built, each having three labelling heads.
Prior to a Nest reaching a labelling station, the label was peeled off and presented to a vacuum pad where it would be inspected by a vision system. The vision system would feedback the angular and linear displacement from datum edges write these parameters to the IPC controlling the system. Once the parameters were gathered a rotary servo motor connected to the vacuum pad would turn to compensate for the angle offset and the final Mover position was adjusted to cater for linear displacement. Once the label was rotated and the Mover positioned correctly, the vacuum pad would engage with the device, leaving the label behind.
Once applied, the label would be left with the ‘tails’ or ‘legs’ trailing and would require wrapping then overwrapping. This was achieved by using a roller connected to an elliptical cam which would engage and disengage the roller at points along a rotary move. A 48 Volt servo motor was used to drive this cam and through a reducing gearbox provided the torque and control to wrap the label in two directions in the short cycle time.
Due to the device requiring to be labelled on two opposite faces, three XTS systems were used with a re-orientate mechanism in between each system. Each of these pick/re-orientate/place modules was driven by a geared 48 Volt servo motor that gave sufficient acceleration and speed to transfer the parts in the required cycle time.
Once the third and final label was applied, the devices were loaded back in to the same batch of trays that they were originally unloaded from. The machine also automatically rejected parts and a buffer system was also used to cater for the shortfall due to rejects.
Label batch, and product data including inspections were recorded as the machine processed the devices through the system.
Using the XTS system allowed SP to overcome problems associated with standard labelling machines, by overcoming the inaccuracies in label reels/webs. The system also allowed us to have complete tracking of the device throughout the system, over the 3 interconnecting modules with a combined length of 15m.
Roy Henderson, Managing Director of SP Technology, commented, “Incorporating the XTS system into our solution allowed us to overcome a number of problems associated with traditional labelling and linear systems. Fast transfer between stations, controllable buffering, and the ability to position the device to suit the label has allowed us to provide a very flexible and configurable system. The construction also allowed us to fully integrate the XTS system into our concept, allowing us to optimise space and work around standard platforms”.