How Digital Pneumatics Add Fast Conversion Flexibility to Food-Packaging Systems
By Festo Canada
Coffee, sugar, salt, pepper, artificial sweeteners, non-dairy creamer, even spice mixes, nowadays, and more food items are packaged in small, low-cost sachets for take-out, delivery, or for airline and hospital meal trays.
There are a lot of dosing machinery on the market for filling flat pouches and sachets of different sizes with dry powders. The challenge for OEMs is distinguishing theirs from the competitions. One approach, taken by Syntegon, with its recently introduced flat pouch Sigpack VPF, was switching during the design process from conventional to digital pneumatics.
The Sigpack VPF and Festo Motion Terminal VTEM, the first integrated cyber-physical motion control platform for pneumatics, were under development during roughly the same timeframe. When the latter was offered to Syntegon engineers, they embraced it for the productivity enhancements made possible by that first commercial product in a new subfield of pneumatic automation.
The cyber-physical system (CPS) technology used by the Motion Terminal uncouples pneumatics from much of its mechanical hardware, instead, making motion control and other functions reliant on Motion Apps downloaded to the manifold. These apps command a single piezo valve type to provide complex movements, variable positioning, condition monitoring and many other “smart” functionalities. In other words, digital pneumatics. Along with its integrated intelligent sensors for control, diagnostics and self-learning, this platform eliminates the need for up to 50 additional hardware components downstream of the manifold, from flow control valves to a wide range of directional control valves.
The attributes of a good, flat-pouch dosing machine include the ability to change packaging formats or contents quickly and flexibly, and meter out quantities as tiny as a few grams with precision. That plays to arguably the biggest benefit of digital pneumatics: the ability to make exponentially faster product and format changeovers via software apps than one can with conventional pneumatics.
The Sigpack VPF, which the manufacturer presents as a freely scalable flat pouch machine, uses the fast changeover capability of digital pneumatics to provide operators with the flexibility to respond rapidly to changing market demand. The machine fills up to 1,800 sachets per minute, using 3-12 “lanes”. The filling mechanism is based on an auger dosing system, known for its high degree of accuracy. Intelligent trend control allows readjustment for more precise dosing.
“Conventional valve technology would have allowed us to have product feeding per lane with vacuum and compressed air supply while also having two-chamber separation, but this would have required additional cleaning components and a proportional valve for each lane,” said Maik Lamprecht, Project Manager for Platform Development, Syntegon.
Switching to digital pneumatics enabled process advantages, plus a reduction in the number of valve slices and peripherals, he added.
With its decentralized dispensing system, each lane of the Sigpack VPF has its own dosing chamber and stock of product, said Rolf Steinemann, the machine’s Product Manager: “Now, different products, such as salt and pepper, can be packaged at the same time on one machine.”
Digital pneumatics makes product feeding much easier, said Lamprecht, “It allowed every lane to be adjusted individually at the push of a button. We use only a third as many valve slices and the flat pouch machine has functions that we could only have otherwise achieved with much greater design effort.”
In the Sigpack VPF, the Motion App “Proportional Pressure Regulation” controls the product feeding for the multi-lane dosing process. With changing pouch sizes and powder consistencies, the Motion Terminal ensures reliable product distribution and a dependable feed process.
Other Motion Apps perform pressure and vacuum measurement for process monitoring, leakage monitoring for checking for valve contamination, as well as individual adjustment of the cleaning and drainage pressure per lane.
“The Festo Motion Terminal has given us a significant boost in terms of process reliability,”
The Motion Terminal also enables adjustable cleaning and ejection pulse. It monitors the filling process and the valve performance using pressure testing. By monitoring pressure and vacuum, wear and contamination can be detected at an early stage. Leakage control also ensures reproducible results. The cleaning and air jet pressure can be set individually for each lane.
Thanks to the fast activation of new functions via apps, only one basic version of the Sigpack VPF is necessary.
“We can then quickly and easily select apps and equip machines with different specifications in line with customer requirements,” said Steinemann.
Digital pneumatics also can perform proportional regulation, soft stop, leakage detection, pneumatic positioning tasks, even energy optimization. That, in turn, simplifies design and maintenance. The Motion Terminal can provide real-time status information like process monitoring for individual machines or entire production lines and processes lines, making the technology IIoT-compliant.