Starting from the dosing and packaging or filling of the product up to the palletizing of large packaging units, modern packaging lines integrate multiple work stations, whose specific tasks are fulfilled in a modular manner by separate machines.
Precision, speed and variability do not only distinguish the packaging systems, rather these aspects also define the requirements on the utilized drive technology. Coupled via a control, the respective drives of the individual axes must work in a highly precise manner in order to fulfill the packaging task as expected, also at a very high cycle speed. The quality of the utilized drive technology is therefore very important. Packaging machine manufacturers therefore trust the drive specialist and system partner Bonfiglioli.
When handling plastic bottles for cosmetics for fast and reliable packaging in boxes, the basic structure, for example, consists of three parts: An infeed unit for the bottles, one for the cardboard packaging and, as a connection element, a pick-and-place gantry robot. In the most simple case, the workflow of this machine functions as follows: The bottle infeed unit takes over the filled, labeled and checked bottles from production, counts them and then puts them into the specified order. The cardboard packaging infeed unit takes the individual box either from a pallet unit or from a conveyor, unfolds it and places it still without any adhesive on a conveyor belt for filling. The gantry robot grips the provided bottles and places them in the opened box. The delivery unit glues the box at the bottom and top with adhesive or adhesive strips.
Bottles in the box with servo technology
Ideally, every function is driven with electrical servo technology. Feeding, packaging and positioning of the bottles, feeding of the cardboard packaging, the pick-and-place of the bottles as well as the removal and closure of the filled boxes must all be well coordinated. The cycles run in fractions of a second. This places great requirements on the drives, especially as concerns acceleration torque, torsional rigidity and brief drive speeds of up to 6500 rpm. These characteristics are inherent to Bonfiglioli’s range of low-backlash planetary gears.
Sensors ensure the correct number and position of the bottles to be packaged. The box filling position is calculated by the corresponding sensor on the conveyor belt in connection with its speed and then transmitted to the axis control of the pick-and-place robot. In both these cases, the particular challenge lies in the dynamics of the start/stop operation and the correct detection of the position. In the case of the gantry robot, the combination of speed and precise positioning with a moving target is required. All machine functions are controlled and coordinated by a powerful PLC. It also provides the connection to upstream and downstream machines, so nothing stands in the way of integrating the packaging machine in a production line. In the direction of the drive, it is supported by the latest generation of inverters. Bonfiglioli Active Next Generation (ANG) inverter family also plays out its strengths here.
Unpacked in a matter of seconds
To make sure that the short cycle time of the central function of the packaging machines is guaranteed, they are driven by highly dynamic electrical drive technology. Also here the Active Next Generation inverter family satisfies the development goals of high dynamics and precise control. With their synchronous functions such as Cyclic Synchronous Position Mode and cycle times of even 1 millisecond, the devices in the Active Next Generation range are designed to meet these requirements. Simple implementation in the controls is possible due to the support of standard objects and standard functions for Motion Control according to CiA 402. This functionality is available with the CANopen and EtherCAT fieldbus systems, which are popular in packaging technology.
Toolless batch change
If batch changes must be performed frequently and the size of the cardboard packaging must be changed, then the speed of format change represents an important competitive advantage: With the electrical servo drives it is possible to change to new formats in a very short period of time. The feeds are reset in no time and all drives for the production process are provided with the current values via the control.
The industrial gear motors from the Bonfiglioli reduction unit product line are used for applications with low accuracy requirements. Normally proven worm gear motors are used for the most simple functions of a packaging machine. Upstream feeding takes place in continuous operation and is therefore predestined for the standard gear motors of Europe’s largest industrial gear manufacturer by volume. Bonfiglioli’s low-backlash planetary gear motors are used for drives that have positioning tasks. The newest BMS range in the combination of TQF gears with BMD motors is particularly compact, so that narrow installation space conditions no longer represent a limitation.
Precision and dynamics from a modular system
The requirements of the packaging machine application are a good fit with the solutions provided by Bonfiglioli. The low-backlash planetary gears permit precision within a fraction of a millimeter and the inverters provide the necessary dynamics and networking. Their use in a wide range of packaging machines demonstrates the variability of the product range. With main drives with a peak torque of several thousand Newton meters up to helper applications with less than 30 Nm, the requirements of a typical packaging machine are completely covered.
In addition to the flexibility of being able to benefit from using a modular kit from a single manufacturer, the guaranteed compliance with the clearance tolerances for the low-backlash planetary gears is very convincing. In pick-and-place robot applications, the lowest possible clearance with three angular minutes is required, whereas many applications permit more cost-efficient gears with a larger clearance of up to 15 angular minutes or even standard gears. The wide range of Bonfiglioli’s servo gear motors and the fact that they mutually supplement each other are well suited in combination with the appropriate inverter series of machine manufacturers. Bonfiglioli provides interested customers with the SERVOsoft design and optimization tool, which calculates and records the optimal combination of planetary gears, servo motor and controller.