Oscar-worthy (bubble) wrap
For its new bubble wrap production line, MS - Protective Solution Packaging has chosen a Torninova solution with twin screw extruder, designed by Sysmac of Omron. Performance, economy, versatility: these are the main properties of the system.
Along with cardboard and polystyrene, it is in all likelihood the most widely used packaging: pluriball, appreciated for its excellent combination of resistance and lightness and which, beyond its apparent simplicity, hides numerous properties resulting from increasingly sophisticated processing methods.
Torninova can legitimately consider itself among the innovators of the sector, given that its business relies on cutting edge technologies, often patented, capable of changing the face of both the process and the very composition of the material. Such is the case of the new solution developed for the Veneto-based MS Srl - Protective Solution Packaging, which Torninova supplied with a machine with twin screw extruder for the production of pluriball with a wide range of weights.
The project’s final objective: bring to the market rolls of bubble wrap with an excellent quality/price ratio, various formats and minimized waste.
The use of a Sysmac platform, as well as the integration of a series of Omron components (machine controller, motors and inverters) was the key to simplifying development operations and offering the end customer a completely adjustable solution, open to future upgrades.
A single environment to facilitate supervision
The Omron NJ machine controller represents the heart of an architecture developed in the spirit of maximum integration.
The inverters and drives (Omron G5 and Omron A1000 retrodriven by encoder) and the field signals and safety components (sensors, photocells, gates) were integrated into the Sysmac platform, guaranteeing a series of advantages in wiring, programming and remote control. In particular, the possibility of using a single bus (EtherCAT) enables gathering all I/Os in a single cable, thus reducing the possibility of errors in initialing. The integration of safety equipment enables not replicating signals within the network: each component is wired only once then transmitted to EtherCAT in order to share information with the rest of the platform.
All parameters and key functions of the machine can be remote controlled, including temperature (set point for temperature adjustment), alarms, anomalies, variable torques in extruder motors, pressures, speed of the motors working on the film in tension, weights (bolt circle), mixtures management. Supervision can also be performed parametrically: operators can edit the formula of a given product, archive it with a name and recall it when needed with one click.
«Such a level of detail represents a very significant advantage over the past» explains Riccardo Marsili, Chief Technical Support Officer at Torninova.
«While before the operator was obliged to set the various configurations on external components, such as an industrial chiller or a gravimetric doser, today all operations have been automated».
The rewinding section has been equipped with Omron Accurax G5 brushless motors. The configuration of the length sets regulates the reel changeover cycle: once a set threshold has been reached, the machine performs cutting and moves the film to a new chuck.
The rewinding requires no cardboard cores. In fact, a patented solution performs coreless rewinding, with no additional elements like cardboard, glues and hotmelt.
The advantage is twofold: on one hand it enables saving on material using a cleaner process, on the other it enhances the volume available, enabling wrapping film to the core.
Function blocks become libraries
Sysmac offers a set of instructions that simplify all programming operations, both in managing logics and for the motion component. In such a way, it is possible to streamline the passage from the various high level functions, leaving the user the freedom to perform adjustments even during operation. The possibility of managing user type libraries enables saving function blocks as models in the library that can be recovered again when needed.
«More than a technological evolution this represents a veritable cultural revolution» explains Stefano Allegrucci, technical manager at Elektron. «Sysmac suberts the rules of design with a practical and decidedly intuitive approach.
Just 5 minutes is enough to move an axis on the platform, regardless of the complexity of motion. All personalized blocks can be recovered for future projects without wasting time».
The presence of a simulator among the various software functions enables testing an application without installing any physical component on board. Specifically, this translates into the possibility of testing the motion of axes and cams in 3D even before purchasing the hardware.
«It’s a tool that safeguards investments» Marsili stresses.
«To have a graphic emulation of the machine capable of showing the motion of the axes without having them physically present in the system enables studying performance, speed, weights and many other parameters in a targeted and preventive approach».
In brief, the use of an open platform like Sysmac has proven decisive in harmonizing all hardware and software components used in the system.
«Opening Sysmac Studio immediately shows you how extensive the level of integration conceived by Omron is» concludes Allegrucci of Elektron. «Everything is within a single platform: logic, motion, safety, even third party masters and modules. It’s a different mental approach in contrast to automation based on discrete compartments: whereas before there was motion, heat regulation, the HMI, each with its own data structure, today thanks to Omron technology, there is a single database, in a single field bus. To go back would be unthinkable».
100 meters/min, reels over 3 meters wide
The machine with twin screw extruder developed by Torninova in partnership with Elektron, starting with a new automation concept based on Omron’s Sysmac platform.
La macchina con estrusore bivite adottata da MS è stata sviluppata da Torninova in collaborazione con Elektron, partendo da un nuovo concetto di automazione basato su piattaforma Sysmac di Omron.
The idea, the project leaders explain, was to take advantage of a single CPU - the Omron NJ machine controller’s - and a single us (EtherCAT) to combine all automation components, from logic to motion and safety.
The result is a machine capable of operation with widths up to 3.40 m at rate of approximately 100 m/min (on 24 hour cycles). «Speeds unthinkable up until 10 years ago, especially certain formats» states Enrico Marcadella, General Manager MS Srl Protective Solution Packaging.
The presence of a twin screw extruder enables working with a wider range of raw materials, from ordinary polyethylene compounds to polyamide and recyclable plastics, with a consistent cost advantage.
In particular, the system uses a co-extrusion process that creates a “sandwich” (two outer layers of polyethylene, two middle layers of tie polymer and a polyamide core). The pluriball is generated from the air and remains trapped between the two films deposited on a thermos-adjustable forming cylinder, connected to a vacuum pump: one fuses to the inside of preset holes, the other sticks above. The compound so formed arrives on the cooling cylinders and, from there, to a third layer unit, where surface lamination is made with polyethylene forms, paper, aluminium, high density sheets and other materials that guarantee additional packaging properties (isolation, reflection…). Finally, cutting and rewinding: the pluriball is re-wound in rolls of variable length according to the operator’s settings, from 50 up to 350-400 linear meters.
A different (and more efficient) way to produce
The system’s flexibility, the advantages in programming and the possibility of identifying and managing problems through tele-assistance have enabled Torninova and Elektron to fully satisfy customer requests.
«This machine - explains Marcadella - enables us to significantly reduce the weight of the pluriball, using a wider range of raw materials, from premium to regenerated, and to work with more useful widths. Furthermore, we employed a coreless rewinder to considerably reduce complexity, eliminating cardboard and glues from the process. From an economic standpoint, the advantage is clear: we can now offer a material that has the same properties of 50 g monoextruded using 40% less raw material. All this while operating at 1000 kg/h. We can say that we are finally able to offer all our customers, including small resellers, reels of any format without using a warehouse and minimizing waste material».
«Omron technology has changed the way to make pluriball» the manager adds. «Now the end customer has a machine that is clearly more flexible, fast and optimized for various product types. From the display panel the operator can order the desired reel type, to which the machine will adapt, performing any formula or format changeovers necessary, which is to say by adjusting the percentage of raw materials to use, both in the film and the width and length of the roll produced».
